linux/drivers/md/dm-thin.c

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/*
* Copyright (C) 2011-2012 Red Hat UK.
*
* This file is released under the GPL.
*/
#include "dm-thin-metadata.h"
#include "dm-bio-prison-v1.h"
#include "dm.h"
#include <linux/device-mapper.h>
#include <linux/dm-io.h>
#include <linux/dm-kcopyd.h>
#include <linux/jiffies.h>
#include <linux/log2.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/sort.h>
#include <linux/rbtree.h>
#define DM_MSG_PREFIX "thin"
/*
* Tunable constants
*/
#define ENDIO_HOOK_POOL_SIZE 1024
#define MAPPING_POOL_SIZE 1024
#define COMMIT_PERIOD HZ
#define NO_SPACE_TIMEOUT_SECS 60
static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
"A percentage of time allocated for copy on write");
/*
* The block size of the device holding pool data must be
* between 64KB and 1GB.
*/
#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
/*
* Device id is restricted to 24 bits.
*/
#define MAX_DEV_ID ((1 << 24) - 1)
/*
* How do we handle breaking sharing of data blocks?
* =================================================
*
* We use a standard copy-on-write btree to store the mappings for the
* devices (note I'm talking about copy-on-write of the metadata here, not
* the data). When you take an internal snapshot you clone the root node
* of the origin btree. After this there is no concept of an origin or a
* snapshot. They are just two device trees that happen to point to the
* same data blocks.
*
* When we get a write in we decide if it's to a shared data block using
* some timestamp magic. If it is, we have to break sharing.
*
* Let's say we write to a shared block in what was the origin. The
* steps are:
*
* i) plug io further to this physical block. (see bio_prison code).
*
* ii) quiesce any read io to that shared data block. Obviously
* including all devices that share this block. (see dm_deferred_set code)
*
* iii) copy the data block to a newly allocate block. This step can be
* missed out if the io covers the block. (schedule_copy).
*
* iv) insert the new mapping into the origin's btree
* (process_prepared_mapping). This act of inserting breaks some
* sharing of btree nodes between the two devices. Breaking sharing only
* effects the btree of that specific device. Btrees for the other
* devices that share the block never change. The btree for the origin
* device as it was after the last commit is untouched, ie. we're using
* persistent data structures in the functional programming sense.
*
* v) unplug io to this physical block, including the io that triggered
* the breaking of sharing.
*
* Steps (ii) and (iii) occur in parallel.
*
* The metadata _doesn't_ need to be committed before the io continues. We
* get away with this because the io is always written to a _new_ block.
* If there's a crash, then:
*
* - The origin mapping will point to the old origin block (the shared
* one). This will contain the data as it was before the io that triggered
* the breaking of sharing came in.
*
* - The snap mapping still points to the old block. As it would after
* the commit.
*
* The downside of this scheme is the timestamp magic isn't perfect, and
* will continue to think that data block in the snapshot device is shared
* even after the write to the origin has broken sharing. I suspect data
* blocks will typically be shared by many different devices, so we're
* breaking sharing n + 1 times, rather than n, where n is the number of
* devices that reference this data block. At the moment I think the
* benefits far, far outweigh the disadvantages.
*/
/*----------------------------------------------------------------*/
/*
* Key building.
*/
enum lock_space {
VIRTUAL,
PHYSICAL
};
static void build_key(struct dm_thin_device *td, enum lock_space ls,
dm_block_t b, dm_block_t e, struct dm_cell_key *key)
{
key->virtual = (ls == VIRTUAL);
key->dev = dm_thin_dev_id(td);
key->block_begin = b;
key->block_end = e;
}
static void build_data_key(struct dm_thin_device *td, dm_block_t b,
struct dm_cell_key *key)
{
build_key(td, PHYSICAL, b, b + 1llu, key);
}
static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
struct dm_cell_key *key)
{
build_key(td, VIRTUAL, b, b + 1llu, key);
}
/*----------------------------------------------------------------*/
#define THROTTLE_THRESHOLD (1 * HZ)
struct throttle {
struct rw_semaphore lock;
unsigned long threshold;
bool throttle_applied;
};
static void throttle_init(struct throttle *t)
{
init_rwsem(&t->lock);
t->throttle_applied = false;
}
static void throttle_work_start(struct throttle *t)
{
t->threshold = jiffies + THROTTLE_THRESHOLD;
}
static void throttle_work_update(struct throttle *t)
{
if (!t->throttle_applied && jiffies > t->threshold) {
down_write(&t->lock);
t->throttle_applied = true;
}
}
static void throttle_work_complete(struct throttle *t)
{
if (t->throttle_applied) {
t->throttle_applied = false;
up_write(&t->lock);
}
}
static void throttle_lock(struct throttle *t)
{
down_read(&t->lock);
}
static void throttle_unlock(struct throttle *t)
{
up_read(&t->lock);
}
/*----------------------------------------------------------------*/
/*
* A pool device ties together a metadata device and a data device. It
* also provides the interface for creating and destroying internal
* devices.
*/
struct dm_thin_new_mapping;
/*
* The pool runs in 4 modes. Ordered in degraded order for comparisons.
*/
enum pool_mode {
PM_WRITE, /* metadata may be changed */
PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
PM_READ_ONLY, /* metadata may not be changed */
PM_FAIL, /* all I/O fails */
};
struct pool_features {
enum pool_mode mode;
bool zero_new_blocks:1;
bool discard_enabled:1;
bool discard_passdown:1;
bool error_if_no_space:1;
};
struct thin_c;
typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
#define CELL_SORT_ARRAY_SIZE 8192
struct pool {
struct list_head list;
struct dm_target *ti; /* Only set if a pool target is bound */
struct mapped_device *pool_md;
struct block_device *md_dev;
struct dm_pool_metadata *pmd;
dm_block_t low_water_blocks;
uint32_t sectors_per_block;
int sectors_per_block_shift;
struct pool_features pf;
bool low_water_triggered:1; /* A dm event has been sent */
bool suspended:1;
bool out_of_data_space:1;
struct dm_bio_prison *prison;
struct dm_kcopyd_client *copier;
struct workqueue_struct *wq;
struct throttle throttle;
struct work_struct worker;
struct delayed_work waker;
struct delayed_work no_space_timeout;
unsigned long last_commit_jiffies;
unsigned ref_count;
spinlock_t lock;
struct bio_list deferred_flush_bios;
struct list_head prepared_mappings;
struct list_head prepared_discards;
struct list_head prepared_discards_pt2;
struct list_head active_thins;
struct dm_deferred_set *shared_read_ds;
struct dm_deferred_set *all_io_ds;
struct dm_thin_new_mapping *next_mapping;
mempool_t mapping_pool;
process_bio_fn process_bio;
process_bio_fn process_discard;
process_cell_fn process_cell;
process_cell_fn process_discard_cell;
process_mapping_fn process_prepared_mapping;
process_mapping_fn process_prepared_discard;
process_mapping_fn process_prepared_discard_pt2;
struct dm_bio_prison_cell **cell_sort_array;
};
static enum pool_mode get_pool_mode(struct pool *pool);
static void metadata_operation_failed(struct pool *pool, const char *op, int r);
/*
* Target context for a pool.
*/
struct pool_c {
struct dm_target *ti;
struct pool *pool;
struct dm_dev *data_dev;
struct dm_dev *metadata_dev;
struct dm_target_callbacks callbacks;
dm_block_t low_water_blocks;
struct pool_features requested_pf; /* Features requested during table load */
struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
};
/*
* Target context for a thin.
*/
struct thin_c {
struct list_head list;
struct dm_dev *pool_dev;
struct dm_dev *origin_dev;
sector_t origin_size;
dm_thin_id dev_id;
struct pool *pool;
struct dm_thin_device *td;
struct mapped_device *thin_md;
bool requeue_mode:1;
spinlock_t lock;
struct list_head deferred_cells;
struct bio_list deferred_bio_list;
struct bio_list retry_on_resume_list;
struct rb_root sort_bio_list; /* sorted list of deferred bios */
dm thin: fix rcu_read_lock being held in code that can sleep Commit c140e1c4e23 ("dm thin: use per thin device deferred bio lists") introduced the use of an rculist for all active thin devices. The use of rcu_read_lock() in process_deferred_bios() can result in a BUG if a dm_bio_prison_cell must be allocated as a side-effect of bio_detain(): BUG: sleeping function called from invalid context at mm/mempool.c:203 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u8:0 3 locks held by kworker/u8:0/6: #0: ("dm-" "thin"){.+.+..}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #1: ((&pool->worker)){+.+...}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #2: (rcu_read_lock){.+.+..}, at: [<ffffffff816360b5>] do_worker+0x5/0x4d0 We can't process deferred bios with the rcu lock held, since dm_bio_prison_cell allocation may block if the bio-prison's cell mempool is exhausted. To fix: - Introduce a refcount and completion field to each thin_c - Add thin_get/put methods for adjusting the refcount. If the refcount hits zero then the completion is triggered. - Initialise refcount to 1 when creating thin_c - When iterating the active_thins list we thin_get() whilst the rcu lock is held. - After the rcu lock is dropped we process the deferred bios for that thin. - When destroying a thin_c we thin_put() and then wait for the completion -- to avoid a race between the worker thread iterating from that thin_c and destroying the thin_c. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-04-08 10:29:01 +00:00
/*
* Ensures the thin is not destroyed until the worker has finished
* iterating the active_thins list.
*/
atomic_t refcount;
struct completion can_destroy;
};
/*----------------------------------------------------------------*/
static bool block_size_is_power_of_two(struct pool *pool)
{
return pool->sectors_per_block_shift >= 0;
}
static sector_t block_to_sectors(struct pool *pool, dm_block_t b)
{
return block_size_is_power_of_two(pool) ?
(b << pool->sectors_per_block_shift) :
(b * pool->sectors_per_block);
}
/*----------------------------------------------------------------*/
struct discard_op {
struct thin_c *tc;
struct blk_plug plug;
struct bio *parent_bio;
struct bio *bio;
};
static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent)
{
BUG_ON(!parent);
op->tc = tc;
blk_start_plug(&op->plug);
op->parent_bio = parent;
op->bio = NULL;
}
static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e)
{
struct thin_c *tc = op->tc;
sector_t s = block_to_sectors(tc->pool, data_b);
sector_t len = block_to_sectors(tc->pool, data_e - data_b);
return __blkdev_issue_discard(tc->pool_dev->bdev, s, len,
GFP_NOWAIT, 0, &op->bio);
}
static void end_discard(struct discard_op *op, int r)
{
if (op->bio) {
/*
* Even if one of the calls to issue_discard failed, we
* need to wait for the chain to complete.
*/
bio_chain(op->bio, op->parent_bio);
bio_set_op_attrs(op->bio, REQ_OP_DISCARD, 0);
submit_bio(op->bio);
}
blk_finish_plug(&op->plug);
/*
* Even if r is set, there could be sub discards in flight that we
* need to wait for.
*/
if (r && !op->parent_bio->bi_status)
op->parent_bio->bi_status = errno_to_blk_status(r);
bio_endio(op->parent_bio);
}
/*----------------------------------------------------------------*/
/*
* wake_worker() is used when new work is queued and when pool_resume is
* ready to continue deferred IO processing.
*/
static void wake_worker(struct pool *pool)
{
queue_work(pool->wq, &pool->worker);
}
/*----------------------------------------------------------------*/
static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
struct dm_bio_prison_cell **cell_result)
{
int r;
struct dm_bio_prison_cell *cell_prealloc;
/*
* Allocate a cell from the prison's mempool.
* This might block but it can't fail.
*/
cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
if (r)
/*
* We reused an old cell; we can get rid of
* the new one.
*/
dm_bio_prison_free_cell(pool->prison, cell_prealloc);
return r;
}
static void cell_release(struct pool *pool,
struct dm_bio_prison_cell *cell,
struct bio_list *bios)
{
dm_cell_release(pool->prison, cell, bios);
dm_bio_prison_free_cell(pool->prison, cell);
}
static void cell_visit_release(struct pool *pool,
void (*fn)(void *, struct dm_bio_prison_cell *),
void *context,
struct dm_bio_prison_cell *cell)
{
dm_cell_visit_release(pool->prison, fn, context, cell);
dm_bio_prison_free_cell(pool->prison, cell);
}
static void cell_release_no_holder(struct pool *pool,
struct dm_bio_prison_cell *cell,
struct bio_list *bios)
{
dm_cell_release_no_holder(pool->prison, cell, bios);
dm_bio_prison_free_cell(pool->prison, cell);
}
static void cell_error_with_code(struct pool *pool,
struct dm_bio_prison_cell *cell, blk_status_t error_code)
{
dm_cell_error(pool->prison, cell, error_code);
dm_bio_prison_free_cell(pool->prison, cell);
}
static blk_status_t get_pool_io_error_code(struct pool *pool)
{
return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR;
}
static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
{
cell_error_with_code(pool, cell, get_pool_io_error_code(pool));
}
static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
{
cell_error_with_code(pool, cell, 0);
}
static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
{
cell_error_with_code(pool, cell, BLK_STS_DM_REQUEUE);
}
/*----------------------------------------------------------------*/
/*
* A global list of pools that uses a struct mapped_device as a key.
*/
static struct dm_thin_pool_table {
struct mutex mutex;
struct list_head pools;
} dm_thin_pool_table;
static void pool_table_init(void)
{
mutex_init(&dm_thin_pool_table.mutex);
INIT_LIST_HEAD(&dm_thin_pool_table.pools);
}
static void pool_table_exit(void)
{
mutex_destroy(&dm_thin_pool_table.mutex);
}
static void __pool_table_insert(struct pool *pool)
{
BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
list_add(&pool->list, &dm_thin_pool_table.pools);
}
static void __pool_table_remove(struct pool *pool)
{
BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
list_del(&pool->list);
}
static struct pool *__pool_table_lookup(struct mapped_device *md)
{
struct pool *pool = NULL, *tmp;
BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
if (tmp->pool_md == md) {
pool = tmp;
break;
}
}
return pool;
}
static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
{
struct pool *pool = NULL, *tmp;
BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
if (tmp->md_dev == md_dev) {
pool = tmp;
break;
}
}
return pool;
}
/*----------------------------------------------------------------*/
struct dm_thin_endio_hook {
struct thin_c *tc;
struct dm_deferred_entry *shared_read_entry;
struct dm_deferred_entry *all_io_entry;
struct dm_thin_new_mapping *overwrite_mapping;
struct rb_node rb_node;
struct dm_bio_prison_cell *cell;
};
static void __merge_bio_list(struct bio_list *bios, struct bio_list *master)
{
bio_list_merge(bios, master);
bio_list_init(master);
}
static void error_bio_list(struct bio_list *bios, blk_status_t error)
{
struct bio *bio;
while ((bio = bio_list_pop(bios))) {
bio->bi_status = error;
bio_endio(bio);
}
}
static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master,
blk_status_t error)
{
struct bio_list bios;
unsigned long flags;
bio_list_init(&bios);
spin_lock_irqsave(&tc->lock, flags);
__merge_bio_list(&bios, master);
spin_unlock_irqrestore(&tc->lock, flags);
error_bio_list(&bios, error);
}
static void requeue_deferred_cells(struct thin_c *tc)
{
struct pool *pool = tc->pool;
unsigned long flags;
struct list_head cells;
struct dm_bio_prison_cell *cell, *tmp;
INIT_LIST_HEAD(&cells);
spin_lock_irqsave(&tc->lock, flags);
list_splice_init(&tc->deferred_cells, &cells);
spin_unlock_irqrestore(&tc->lock, flags);
list_for_each_entry_safe(cell, tmp, &cells, user_list)
cell_requeue(pool, cell);
}
static void requeue_io(struct thin_c *tc)
{
struct bio_list bios;
unsigned long flags;
bio_list_init(&bios);
spin_lock_irqsave(&tc->lock, flags);
__merge_bio_list(&bios, &tc->deferred_bio_list);
__merge_bio_list(&bios, &tc->retry_on_resume_list);
spin_unlock_irqrestore(&tc->lock, flags);
error_bio_list(&bios, BLK_STS_DM_REQUEUE);
requeue_deferred_cells(tc);
}
static void error_retry_list_with_code(struct pool *pool, blk_status_t error)
{
struct thin_c *tc;
rcu_read_lock();
list_for_each_entry_rcu(tc, &pool->active_thins, list)
error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
rcu_read_unlock();
}
static void error_retry_list(struct pool *pool)
{
error_retry_list_with_code(pool, get_pool_io_error_code(pool));
}
/*
* This section of code contains the logic for processing a thin device's IO.
* Much of the code depends on pool object resources (lists, workqueues, etc)
* but most is exclusively called from the thin target rather than the thin-pool
* target.
*/
static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
{
struct pool *pool = tc->pool;
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
sector_t block_nr = bio->bi_iter.bi_sector;
if (block_size_is_power_of_two(pool))
block_nr >>= pool->sectors_per_block_shift;
else
(void) sector_div(block_nr, pool->sectors_per_block);
return block_nr;
}
/*
* Returns the _complete_ blocks that this bio covers.
*/
static void get_bio_block_range(struct thin_c *tc, struct bio *bio,
dm_block_t *begin, dm_block_t *end)
{
struct pool *pool = tc->pool;
sector_t b = bio->bi_iter.bi_sector;
sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT);
b += pool->sectors_per_block - 1ull; /* so we round up */
if (block_size_is_power_of_two(pool)) {
b >>= pool->sectors_per_block_shift;
e >>= pool->sectors_per_block_shift;
} else {
(void) sector_div(b, pool->sectors_per_block);
(void) sector_div(e, pool->sectors_per_block);
}
if (e < b)
/* Can happen if the bio is within a single block. */
e = b;
*begin = b;
*end = e;
}
static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
{
struct pool *pool = tc->pool;
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
sector_t bi_sector = bio->bi_iter.bi_sector;
bio_set_dev(bio, tc->pool_dev->bdev);
if (block_size_is_power_of_two(pool))
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
bio->bi_iter.bi_sector =
(block << pool->sectors_per_block_shift) |
(bi_sector & (pool->sectors_per_block - 1));
else
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
sector_div(bi_sector, pool->sectors_per_block);
}
static void remap_to_origin(struct thin_c *tc, struct bio *bio)
{
bio_set_dev(bio, tc->origin_dev->bdev);
}
static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
{
return op_is_flush(bio->bi_opf) &&
dm_thin_changed_this_transaction(tc->td);
}
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
static void inc_all_io_entry(struct pool *pool, struct bio *bio)
{
struct dm_thin_endio_hook *h;
if (bio_op(bio) == REQ_OP_DISCARD)
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
return;
h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
}
static void issue(struct thin_c *tc, struct bio *bio)
{
struct pool *pool = tc->pool;
unsigned long flags;
if (!bio_triggers_commit(tc, bio)) {
generic_make_request(bio);
return;
}
/*
* Complete bio with an error if earlier I/O caused changes to
* the metadata that can't be committed e.g, due to I/O errors
* on the metadata device.
*/
if (dm_thin_aborted_changes(tc->td)) {
bio_io_error(bio);
return;
}
/*
* Batch together any bios that trigger commits and then issue a
* single commit for them in process_deferred_bios().
*/
spin_lock_irqsave(&pool->lock, flags);
bio_list_add(&pool->deferred_flush_bios, bio);
spin_unlock_irqrestore(&pool->lock, flags);
}
static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
{
remap_to_origin(tc, bio);
issue(tc, bio);
}
static void remap_and_issue(struct thin_c *tc, struct bio *bio,
dm_block_t block)
{
remap(tc, bio, block);
issue(tc, bio);
}
/*----------------------------------------------------------------*/
/*
* Bio endio functions.
*/
struct dm_thin_new_mapping {
struct list_head list;
bool pass_discard:1;
bool maybe_shared:1;
/*
* Track quiescing, copying and zeroing preparation actions. When this
* counter hits zero the block is prepared and can be inserted into the
* btree.
*/
atomic_t prepare_actions;
blk_status_t status;
struct thin_c *tc;
dm_block_t virt_begin, virt_end;
dm_block_t data_block;
struct dm_bio_prison_cell *cell;
/*
* If the bio covers the whole area of a block then we can avoid
* zeroing or copying. Instead this bio is hooked. The bio will
* still be in the cell, so care has to be taken to avoid issuing
* the bio twice.
*/
struct bio *bio;
bio_end_io_t *saved_bi_end_io;
};
static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
{
struct pool *pool = m->tc->pool;
if (atomic_dec_and_test(&m->prepare_actions)) {
list_add_tail(&m->list, &pool->prepared_mappings);
wake_worker(pool);
}
}
static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
{
unsigned long flags;
struct pool *pool = m->tc->pool;
spin_lock_irqsave(&pool->lock, flags);
__complete_mapping_preparation(m);
spin_unlock_irqrestore(&pool->lock, flags);
}
static void copy_complete(int read_err, unsigned long write_err, void *context)
{
struct dm_thin_new_mapping *m = context;
m->status = read_err || write_err ? BLK_STS_IOERR : 0;
complete_mapping_preparation(m);
}
static void overwrite_endio(struct bio *bio)
{
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
struct dm_thin_new_mapping *m = h->overwrite_mapping;
bio->bi_end_io = m->saved_bi_end_io;
m->status = bio->bi_status;
complete_mapping_preparation(m);
}
/*----------------------------------------------------------------*/
/*
* Workqueue.
*/
/*
* Prepared mapping jobs.
*/
/*
* This sends the bios in the cell, except the original holder, back
* to the deferred_bios list.
*/
static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
{
struct pool *pool = tc->pool;
unsigned long flags;
spin_lock_irqsave(&tc->lock, flags);
cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
spin_unlock_irqrestore(&tc->lock, flags);
wake_worker(pool);
}
static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
struct remap_info {
struct thin_c *tc;
struct bio_list defer_bios;
struct bio_list issue_bios;
};
static void __inc_remap_and_issue_cell(void *context,
struct dm_bio_prison_cell *cell)
{
struct remap_info *info = context;
struct bio *bio;
while ((bio = bio_list_pop(&cell->bios))) {
if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD)
bio_list_add(&info->defer_bios, bio);
else {
inc_all_io_entry(info->tc->pool, bio);
/*
* We can't issue the bios with the bio prison lock
* held, so we add them to a list to issue on
* return from this function.
*/
bio_list_add(&info->issue_bios, bio);
}
}
}
static void inc_remap_and_issue_cell(struct thin_c *tc,
struct dm_bio_prison_cell *cell,
dm_block_t block)
{
struct bio *bio;
struct remap_info info;
info.tc = tc;
bio_list_init(&info.defer_bios);
bio_list_init(&info.issue_bios);
/*
* We have to be careful to inc any bios we're about to issue
* before the cell is released, and avoid a race with new bios
* being added to the cell.
*/
cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
&info, cell);
while ((bio = bio_list_pop(&info.defer_bios)))
thin_defer_bio(tc, bio);
while ((bio = bio_list_pop(&info.issue_bios)))
remap_and_issue(info.tc, bio, block);
}
static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
{
cell_error(m->tc->pool, m->cell);
list_del(&m->list);
mempool_free(m, &m->tc->pool->mapping_pool);
}
static void process_prepared_mapping(struct dm_thin_new_mapping *m)
{
struct thin_c *tc = m->tc;
struct pool *pool = tc->pool;
struct bio *bio = m->bio;
int r;
if (m->status) {
cell_error(pool, m->cell);
goto out;
}
/*
* Commit the prepared block into the mapping btree.
* Any I/O for this block arriving after this point will get
* remapped to it directly.
*/
r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block);
if (r) {
metadata_operation_failed(pool, "dm_thin_insert_block", r);
cell_error(pool, m->cell);
goto out;
}
/*
* Release any bios held while the block was being provisioned.
* If we are processing a write bio that completely covers the block,
* we already processed it so can ignore it now when processing
* the bios in the cell.
*/
if (bio) {
inc_remap_and_issue_cell(tc, m->cell, m->data_block);
bio_endio(bio);
} else {
inc_all_io_entry(tc->pool, m->cell->holder);
remap_and_issue(tc, m->cell->holder, m->data_block);
inc_remap_and_issue_cell(tc, m->cell, m->data_block);
}
out:
list_del(&m->list);
mempool_free(m, &pool->mapping_pool);
}
/*----------------------------------------------------------------*/
static void free_discard_mapping(struct dm_thin_new_mapping *m)
{
struct thin_c *tc = m->tc;
if (m->cell)
cell_defer_no_holder(tc, m->cell);
mempool_free(m, &tc->pool->mapping_pool);
}
static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
{
bio_io_error(m->bio);
free_discard_mapping(m);
}
static void process_prepared_discard_success(struct dm_thin_new_mapping *m)
{
bio_endio(m->bio);
free_discard_mapping(m);
}
static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m)
{
int r;
struct thin_c *tc = m->tc;
r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end);
if (r) {
metadata_operation_failed(tc->pool, "dm_thin_remove_range", r);
bio_io_error(m->bio);
} else
bio_endio(m->bio);
cell_defer_no_holder(tc, m->cell);
mempool_free(m, &tc->pool->mapping_pool);
}
/*----------------------------------------------------------------*/
static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m,
struct bio *discard_parent)
{
/*
* We've already unmapped this range of blocks, but before we
* passdown we have to check that these blocks are now unused.
*/
int r = 0;
bool used = true;
struct thin_c *tc = m->tc;
struct pool *pool = tc->pool;
dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
struct discard_op op;
begin_discard(&op, tc, discard_parent);
while (b != end) {
/* find start of unmapped run */
for (; b < end; b++) {
r = dm_pool_block_is_used(pool->pmd, b, &used);
if (r)
goto out;
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
if (!used)
break;
}
if (b == end)
break;
/* find end of run */
for (e = b + 1; e != end; e++) {
r = dm_pool_block_is_used(pool->pmd, e, &used);
if (r)
goto out;
if (used)
break;
}
r = issue_discard(&op, b, e);
if (r)
goto out;
b = e;
}
out:
end_discard(&op, r);
}
static void queue_passdown_pt2(struct dm_thin_new_mapping *m)
{
unsigned long flags;
struct pool *pool = m->tc->pool;
spin_lock_irqsave(&pool->lock, flags);
list_add_tail(&m->list, &pool->prepared_discards_pt2);
spin_unlock_irqrestore(&pool->lock, flags);
wake_worker(pool);
}
static void passdown_endio(struct bio *bio)
{
/*
* It doesn't matter if the passdown discard failed, we still want
* to unmap (we ignore err).
*/
queue_passdown_pt2(bio->bi_private);
dm thin: fix a memory leak when passing discard bio down dm-thin does not free the discard_parent bio after all chained sub bios finished. The following kmemleak report could be observed after pool with discard_passdown option processes discard bios in linux v4.11-rc7. To fix this, we drop the discard_parent bio reference when its endio (passdown_endio) called. unreferenced object 0xffff8803d6b29700 (size 256): comm "kworker/u8:0", pid 30349, jiffies 4379504020 (age 143002.776s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 01 00 00 00 00 00 00 f0 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff81a5efd9>] kmemleak_alloc+0x49/0xa0 [<ffffffff8114ec34>] kmem_cache_alloc+0xb4/0x100 [<ffffffff8110eec0>] mempool_alloc_slab+0x10/0x20 [<ffffffff8110efa5>] mempool_alloc+0x55/0x150 [<ffffffff81374939>] bio_alloc_bioset+0xb9/0x260 [<ffffffffa018fd20>] process_prepared_discard_passdown_pt1+0x40/0x1c0 [dm_thin_pool] [<ffffffffa018b409>] break_up_discard_bio+0x1a9/0x200 [dm_thin_pool] [<ffffffffa018b484>] process_discard_cell_passdown+0x24/0x40 [dm_thin_pool] [<ffffffffa018b24d>] process_discard_bio+0xdd/0xf0 [dm_thin_pool] [<ffffffffa018ecf6>] do_worker+0xa76/0xd50 [dm_thin_pool] [<ffffffff81086239>] process_one_work+0x139/0x370 [<ffffffff810867b1>] worker_thread+0x61/0x450 [<ffffffff8108b316>] kthread+0xd6/0xf0 [<ffffffff81a6cd1f>] ret_from_fork+0x3f/0x70 [<ffffffffffffffff>] 0xffffffffffffffff Cc: stable@vger.kernel.org Signed-off-by: Dennis Yang <dennisyang@qnap.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-04-18 07:27:06 +00:00
bio_put(bio);
}
static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m)
{
int r;
struct thin_c *tc = m->tc;
struct pool *pool = tc->pool;
struct bio *discard_parent;
dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin);
/*
* Only this thread allocates blocks, so we can be sure that the
* newly unmapped blocks will not be allocated before the end of
* the function.
*/
r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end);
if (r) {
metadata_operation_failed(pool, "dm_thin_remove_range", r);
bio_io_error(m->bio);
cell_defer_no_holder(tc, m->cell);
mempool_free(m, &pool->mapping_pool);
return;
}
dm thin: do not queue freed thin mapping for next stage processing process_prepared_discard_passdown_pt1() should cleanup dm_thin_new_mapping in cases of error. dm_pool_inc_data_range() can fail trying to get a block reference: metadata operation 'dm_pool_inc_data_range' failed: error = -61 When dm_pool_inc_data_range() fails, dm thin aborts current metadata transaction and marks pool as PM_READ_ONLY. Memory for thin mapping is released as well. However, current thin mapping will be queued onto next stage as part of queue_passdown_pt2() or passdown_endio(). This dangling thin mapping memory when processed and accessed in next stage will lead to device mapper crashing. Code flow without fix: -> process_prepared_discard_passdown_pt1(m) -> dm_thin_remove_range() -> discard passdown --> passdown_endio(m) queues m onto next stage -> dm_pool_inc_data_range() fails, frees memory m but does not remove it from next stage queue -> process_prepared_discard_passdown_pt2(m) -> processes freed memory m and crashes One such stack: Call Trace: [<ffffffffa037a46f>] dm_cell_release_no_holder+0x2f/0x70 [dm_bio_prison] [<ffffffffa039b6dc>] cell_defer_no_holder+0x3c/0x80 [dm_thin_pool] [<ffffffffa039b88b>] process_prepared_discard_passdown_pt2+0x4b/0x90 [dm_thin_pool] [<ffffffffa0399611>] process_prepared+0x81/0xa0 [dm_thin_pool] [<ffffffffa039e735>] do_worker+0xc5/0x820 [dm_thin_pool] [<ffffffff8152bf54>] ? __schedule+0x244/0x680 [<ffffffff81087e72>] ? pwq_activate_delayed_work+0x42/0xb0 [<ffffffff81089f53>] process_one_work+0x153/0x3f0 [<ffffffff8108a71b>] worker_thread+0x12b/0x4b0 [<ffffffff8108a5f0>] ? rescuer_thread+0x350/0x350 [<ffffffff8108fd6a>] kthread+0xca/0xe0 [<ffffffff8108fca0>] ? kthread_park+0x60/0x60 [<ffffffff81530b45>] ret_from_fork+0x25/0x30 The fix is to first take the block ref count for discarded block and then do a passdown discard of this block. If block ref count fails, then bail out aborting current metadata transaction, mark pool as PM_READ_ONLY and also free current thin mapping memory (existing error handling code) without queueing this thin mapping onto next stage of processing. If block ref count succeeds, then passdown discard of this block. Discard callback of passdown_endio() will queue this thin mapping onto next stage of processing. Code flow with fix: -> process_prepared_discard_passdown_pt1(m) -> dm_thin_remove_range() -> dm_pool_inc_data_range() --> if fails, free memory m and bail out -> discard passdown --> passdown_endio(m) queues m onto next stage Cc: stable <stable@vger.kernel.org> # v4.9+ Reviewed-by: Eduardo Valentin <eduval@amazon.com> Reviewed-by: Cristian Gafton <gafton@amazon.com> Reviewed-by: Anchal Agarwal <anchalag@amazon.com> Signed-off-by: Vallish Vaidyeshwara <vallish@amazon.com> Reviewed-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-06-23 18:53:06 +00:00
/*
* Increment the unmapped blocks. This prevents a race between the
* passdown io and reallocation of freed blocks.
*/
r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
if (r) {
metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
bio_io_error(m->bio);
cell_defer_no_holder(tc, m->cell);
mempool_free(m, &pool->mapping_pool);
dm thin: do not queue freed thin mapping for next stage processing process_prepared_discard_passdown_pt1() should cleanup dm_thin_new_mapping in cases of error. dm_pool_inc_data_range() can fail trying to get a block reference: metadata operation 'dm_pool_inc_data_range' failed: error = -61 When dm_pool_inc_data_range() fails, dm thin aborts current metadata transaction and marks pool as PM_READ_ONLY. Memory for thin mapping is released as well. However, current thin mapping will be queued onto next stage as part of queue_passdown_pt2() or passdown_endio(). This dangling thin mapping memory when processed and accessed in next stage will lead to device mapper crashing. Code flow without fix: -> process_prepared_discard_passdown_pt1(m) -> dm_thin_remove_range() -> discard passdown --> passdown_endio(m) queues m onto next stage -> dm_pool_inc_data_range() fails, frees memory m but does not remove it from next stage queue -> process_prepared_discard_passdown_pt2(m) -> processes freed memory m and crashes One such stack: Call Trace: [<ffffffffa037a46f>] dm_cell_release_no_holder+0x2f/0x70 [dm_bio_prison] [<ffffffffa039b6dc>] cell_defer_no_holder+0x3c/0x80 [dm_thin_pool] [<ffffffffa039b88b>] process_prepared_discard_passdown_pt2+0x4b/0x90 [dm_thin_pool] [<ffffffffa0399611>] process_prepared+0x81/0xa0 [dm_thin_pool] [<ffffffffa039e735>] do_worker+0xc5/0x820 [dm_thin_pool] [<ffffffff8152bf54>] ? __schedule+0x244/0x680 [<ffffffff81087e72>] ? pwq_activate_delayed_work+0x42/0xb0 [<ffffffff81089f53>] process_one_work+0x153/0x3f0 [<ffffffff8108a71b>] worker_thread+0x12b/0x4b0 [<ffffffff8108a5f0>] ? rescuer_thread+0x350/0x350 [<ffffffff8108fd6a>] kthread+0xca/0xe0 [<ffffffff8108fca0>] ? kthread_park+0x60/0x60 [<ffffffff81530b45>] ret_from_fork+0x25/0x30 The fix is to first take the block ref count for discarded block and then do a passdown discard of this block. If block ref count fails, then bail out aborting current metadata transaction, mark pool as PM_READ_ONLY and also free current thin mapping memory (existing error handling code) without queueing this thin mapping onto next stage of processing. If block ref count succeeds, then passdown discard of this block. Discard callback of passdown_endio() will queue this thin mapping onto next stage of processing. Code flow with fix: -> process_prepared_discard_passdown_pt1(m) -> dm_thin_remove_range() -> dm_pool_inc_data_range() --> if fails, free memory m and bail out -> discard passdown --> passdown_endio(m) queues m onto next stage Cc: stable <stable@vger.kernel.org> # v4.9+ Reviewed-by: Eduardo Valentin <eduval@amazon.com> Reviewed-by: Cristian Gafton <gafton@amazon.com> Reviewed-by: Anchal Agarwal <anchalag@amazon.com> Signed-off-by: Vallish Vaidyeshwara <vallish@amazon.com> Reviewed-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-06-23 18:53:06 +00:00
return;
}
discard_parent = bio_alloc(GFP_NOIO, 1);
if (!discard_parent) {
DMWARN("%s: unable to allocate top level discard bio for passdown. Skipping passdown.",
dm_device_name(tc->pool->pool_md));
queue_passdown_pt2(m);
} else {
discard_parent->bi_end_io = passdown_endio;
discard_parent->bi_private = m;
if (m->maybe_shared)
passdown_double_checking_shared_status(m, discard_parent);
else {
struct discard_op op;
begin_discard(&op, tc, discard_parent);
r = issue_discard(&op, m->data_block, data_end);
end_discard(&op, r);
}
}
}
static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m)
{
int r;
struct thin_c *tc = m->tc;
struct pool *pool = tc->pool;
/*
* The passdown has completed, so now we can decrement all those
* unmapped blocks.
*/
r = dm_pool_dec_data_range(pool->pmd, m->data_block,
m->data_block + (m->virt_end - m->virt_begin));
if (r) {
metadata_operation_failed(pool, "dm_pool_dec_data_range", r);
bio_io_error(m->bio);
} else
bio_endio(m->bio);
cell_defer_no_holder(tc, m->cell);
mempool_free(m, &pool->mapping_pool);
}
static void process_prepared(struct pool *pool, struct list_head *head,
process_mapping_fn *fn)
{
unsigned long flags;
struct list_head maps;
struct dm_thin_new_mapping *m, *tmp;
INIT_LIST_HEAD(&maps);
spin_lock_irqsave(&pool->lock, flags);
list_splice_init(head, &maps);
spin_unlock_irqrestore(&pool->lock, flags);
list_for_each_entry_safe(m, tmp, &maps, list)
(*fn)(m);
}
/*
* Deferred bio jobs.
*/
static int io_overlaps_block(struct pool *pool, struct bio *bio)
{
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
return bio->bi_iter.bi_size ==
(pool->sectors_per_block << SECTOR_SHIFT);
}
static int io_overwrites_block(struct pool *pool, struct bio *bio)
{
return (bio_data_dir(bio) == WRITE) &&
io_overlaps_block(pool, bio);
}
static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
bio_end_io_t *fn)
{
*save = bio->bi_end_io;
bio->bi_end_io = fn;
}
static int ensure_next_mapping(struct pool *pool)
{
if (pool->next_mapping)
return 0;
pool->next_mapping = mempool_alloc(&pool->mapping_pool, GFP_ATOMIC);
return pool->next_mapping ? 0 : -ENOMEM;
}
static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
{
struct dm_thin_new_mapping *m = pool->next_mapping;
BUG_ON(!pool->next_mapping);
memset(m, 0, sizeof(struct dm_thin_new_mapping));
INIT_LIST_HEAD(&m->list);
m->bio = NULL;
pool->next_mapping = NULL;
return m;
}
static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
sector_t begin, sector_t end)
{
int r;
struct dm_io_region to;
to.bdev = tc->pool_dev->bdev;
to.sector = begin;
to.count = end - begin;
r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
if (r < 0) {
DMERR_LIMIT("dm_kcopyd_zero() failed");
copy_complete(1, 1, m);
}
}
static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
dm_block_t data_begin,
struct dm_thin_new_mapping *m)
{
struct pool *pool = tc->pool;
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
h->overwrite_mapping = m;
m->bio = bio;
save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
inc_all_io_entry(pool, bio);
remap_and_issue(tc, bio, data_begin);
}
/*
* A partial copy also needs to zero the uncopied region.
*/
static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
struct dm_dev *origin, dm_block_t data_origin,
dm_block_t data_dest,
struct dm_bio_prison_cell *cell, struct bio *bio,
sector_t len)
{
int r;
struct pool *pool = tc->pool;
struct dm_thin_new_mapping *m = get_next_mapping(pool);
m->tc = tc;
m->virt_begin = virt_block;
m->virt_end = virt_block + 1u;
m->data_block = data_dest;
m->cell = cell;
/*
* quiesce action + copy action + an extra reference held for the
* duration of this function (we may need to inc later for a
* partial zero).
*/
atomic_set(&m->prepare_actions, 3);
if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
complete_mapping_preparation(m); /* already quiesced */
/*
* IO to pool_dev remaps to the pool target's data_dev.
*
* If the whole block of data is being overwritten, we can issue the
* bio immediately. Otherwise we use kcopyd to clone the data first.
*/
if (io_overwrites_block(pool, bio))
remap_and_issue_overwrite(tc, bio, data_dest, m);
else {
struct dm_io_region from, to;
from.bdev = origin->bdev;
from.sector = data_origin * pool->sectors_per_block;
from.count = len;
to.bdev = tc->pool_dev->bdev;
to.sector = data_dest * pool->sectors_per_block;
to.count = len;
r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
0, copy_complete, m);
if (r < 0) {
DMERR_LIMIT("dm_kcopyd_copy() failed");
copy_complete(1, 1, m);
/*
* We allow the zero to be issued, to simplify the
* error path. Otherwise we'd need to start
* worrying about decrementing the prepare_actions
* counter.
*/
}
/*
* Do we need to zero a tail region?
*/
if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
atomic_inc(&m->prepare_actions);
ll_zero(tc, m,
data_dest * pool->sectors_per_block + len,
(data_dest + 1) * pool->sectors_per_block);
}
}
complete_mapping_preparation(m); /* drop our ref */
}
static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
dm_block_t data_origin, dm_block_t data_dest,
struct dm_bio_prison_cell *cell, struct bio *bio)
{
schedule_copy(tc, virt_block, tc->pool_dev,
data_origin, data_dest, cell, bio,
tc->pool->sectors_per_block);
}
static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
dm_block_t data_block, struct dm_bio_prison_cell *cell,
struct bio *bio)
{
struct pool *pool = tc->pool;
struct dm_thin_new_mapping *m = get_next_mapping(pool);
atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
m->tc = tc;
m->virt_begin = virt_block;
m->virt_end = virt_block + 1u;
m->data_block = data_block;
m->cell = cell;
/*
* If the whole block of data is being overwritten or we are not
* zeroing pre-existing data, we can issue the bio immediately.
* Otherwise we use kcopyd to zero the data first.
*/
if (pool->pf.zero_new_blocks) {
if (io_overwrites_block(pool, bio))
remap_and_issue_overwrite(tc, bio, data_block, m);
else
ll_zero(tc, m, data_block * pool->sectors_per_block,
(data_block + 1) * pool->sectors_per_block);
} else
process_prepared_mapping(m);
}
static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
dm_block_t data_dest,
struct dm_bio_prison_cell *cell, struct bio *bio)
{
struct pool *pool = tc->pool;
sector_t virt_block_begin = virt_block * pool->sectors_per_block;
sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
if (virt_block_end <= tc->origin_size)
schedule_copy(tc, virt_block, tc->origin_dev,
virt_block, data_dest, cell, bio,
pool->sectors_per_block);
else if (virt_block_begin < tc->origin_size)
schedule_copy(tc, virt_block, tc->origin_dev,
virt_block, data_dest, cell, bio,
tc->origin_size - virt_block_begin);
else
schedule_zero(tc, virt_block, data_dest, cell, bio);
}
static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
static void check_for_space(struct pool *pool)
{
int r;
dm_block_t nr_free;
if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
return;
r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
if (r)
return;
if (nr_free)
set_pool_mode(pool, PM_WRITE);
}
/*
* A non-zero return indicates read_only or fail_io mode.
* Many callers don't care about the return value.
*/
static int commit(struct pool *pool)
{
int r;
if (get_pool_mode(pool) >= PM_READ_ONLY)
return -EINVAL;
r = dm_pool_commit_metadata(pool->pmd);
if (r)
metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
else
check_for_space(pool);
return r;
}
static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
{
unsigned long flags;
if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
DMWARN("%s: reached low water mark for data device: sending event.",
dm_device_name(pool->pool_md));
spin_lock_irqsave(&pool->lock, flags);
pool->low_water_triggered = true;
spin_unlock_irqrestore(&pool->lock, flags);
dm_table_event(pool->ti->table);
}
}
static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
{
int r;
dm_block_t free_blocks;
struct pool *pool = tc->pool;
if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
return -EINVAL;
r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
if (r) {
metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
return r;
}
check_low_water_mark(pool, free_blocks);
if (!free_blocks) {
/*
* Try to commit to see if that will free up some
* more space.
*/
r = commit(pool);
if (r)
return r;
r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
if (r) {
metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
return r;
}
if (!free_blocks) {
set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
return -ENOSPC;
}
}
r = dm_pool_alloc_data_block(pool->pmd, result);
dm thin: switch to read-only mode if metadata space is exhausted Switch the thin pool to read-only mode in alloc_data_block() if dm_pool_alloc_data_block() fails because the pool's metadata space is exhausted. Differentiate between data and metadata space in messages about no free space available. This issue was noticed with the device-mapper-test-suite using: dmtest run --suite thin-provisioning -n /exhausting_metadata_space_causes_fail_mode/ The quantity of errors logged in this case must be reduced. before patch: device-mapper: thin: 253:4: reached low water mark for metadata device: sending event. device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed <snip ... these repeat for a _very_ long while ... > device-mapper: space map metadata: unable to allocate new metadata block device-mapper: thin: 253:4: commit failed: error = -28 device-mapper: thin: 253:4: switching pool to read-only mode after patch: device-mapper: thin: 253:4: reached low water mark for metadata device: sending event. device-mapper: space map metadata: unable to allocate new metadata block device-mapper: thin: 253:4: no free metadata space available. device-mapper: thin: 253:4: switching pool to read-only mode Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Cc: stable@vger.kernel.org
2013-12-03 17:20:57 +00:00
if (r) {
metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
return r;
dm thin: switch to read-only mode if metadata space is exhausted Switch the thin pool to read-only mode in alloc_data_block() if dm_pool_alloc_data_block() fails because the pool's metadata space is exhausted. Differentiate between data and metadata space in messages about no free space available. This issue was noticed with the device-mapper-test-suite using: dmtest run --suite thin-provisioning -n /exhausting_metadata_space_causes_fail_mode/ The quantity of errors logged in this case must be reduced. before patch: device-mapper: thin: 253:4: reached low water mark for metadata device: sending event. device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed device-mapper: space map metadata: unable to allocate new metadata block device-mapper: space map common: dm_tm_shadow_block() failed <snip ... these repeat for a _very_ long while ... > device-mapper: space map metadata: unable to allocate new metadata block device-mapper: thin: 253:4: commit failed: error = -28 device-mapper: thin: 253:4: switching pool to read-only mode after patch: device-mapper: thin: 253:4: reached low water mark for metadata device: sending event. device-mapper: space map metadata: unable to allocate new metadata block device-mapper: thin: 253:4: no free metadata space available. device-mapper: thin: 253:4: switching pool to read-only mode Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Cc: stable@vger.kernel.org
2013-12-03 17:20:57 +00:00
}
return 0;
}
/*
* If we have run out of space, queue bios until the device is
* resumed, presumably after having been reloaded with more space.
*/
static void retry_on_resume(struct bio *bio)
{
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
struct thin_c *tc = h->tc;
unsigned long flags;
spin_lock_irqsave(&tc->lock, flags);
bio_list_add(&tc->retry_on_resume_list, bio);
spin_unlock_irqrestore(&tc->lock, flags);
}
static blk_status_t should_error_unserviceable_bio(struct pool *pool)
{
enum pool_mode m = get_pool_mode(pool);
switch (m) {
case PM_WRITE:
/* Shouldn't get here */
DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
return BLK_STS_IOERR;
case PM_OUT_OF_DATA_SPACE:
return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0;
case PM_READ_ONLY:
case PM_FAIL:
return BLK_STS_IOERR;
default:
/* Shouldn't get here */
DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
return BLK_STS_IOERR;
}
}
static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
{
blk_status_t error = should_error_unserviceable_bio(pool);
if (error) {
bio->bi_status = error;
bio_endio(bio);
} else
retry_on_resume(bio);
}
static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
{
struct bio *bio;
struct bio_list bios;
blk_status_t error;
error = should_error_unserviceable_bio(pool);
if (error) {
cell_error_with_code(pool, cell, error);
return;
}
bio_list_init(&bios);
cell_release(pool, cell, &bios);
while ((bio = bio_list_pop(&bios)))
retry_on_resume(bio);
}
static void process_discard_cell_no_passdown(struct thin_c *tc,
struct dm_bio_prison_cell *virt_cell)
{
struct pool *pool = tc->pool;
struct dm_thin_new_mapping *m = get_next_mapping(pool);
/*
* We don't need to lock the data blocks, since there's no
* passdown. We only lock data blocks for allocation and breaking sharing.
*/
m->tc = tc;
m->virt_begin = virt_cell->key.block_begin;
m->virt_end = virt_cell->key.block_end;
m->cell = virt_cell;
m->bio = virt_cell->holder;
if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
pool->process_prepared_discard(m);
}
static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end,
struct bio *bio)
{
struct pool *pool = tc->pool;
int r;
bool maybe_shared;
struct dm_cell_key data_key;
struct dm_bio_prison_cell *data_cell;
struct dm_thin_new_mapping *m;
dm_block_t virt_begin, virt_end, data_begin;
while (begin != end) {
r = ensure_next_mapping(pool);
if (r)
/* we did our best */
return;
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end,
&data_begin, &maybe_shared);
if (r)
/*
* Silently fail, letting any mappings we've
* created complete.
*/
break;
build_key(tc->td, PHYSICAL, data_begin, data_begin + (virt_end - virt_begin), &data_key);
if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) {
/* contention, we'll give up with this range */
begin = virt_end;
continue;
}
/*
* IO may still be going to the destination block. We must
* quiesce before we can do the removal.
*/
m = get_next_mapping(pool);
m->tc = tc;
m->maybe_shared = maybe_shared;
m->virt_begin = virt_begin;
m->virt_end = virt_end;
m->data_block = data_begin;
m->cell = data_cell;
m->bio = bio;
/*
* The parent bio must not complete before sub discard bios are
* chained to it (see end_discard's bio_chain)!
*
* This per-mapping bi_remaining increment is paired with
* the implicit decrement that occurs via bio_endio() in
* end_discard().
*/
bio_inc_remaining(bio);
if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
pool->process_prepared_discard(m);
begin = virt_end;
}
}
static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell)
{
struct bio *bio = virt_cell->holder;
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
/*
* The virt_cell will only get freed once the origin bio completes.
* This means it will remain locked while all the individual
* passdown bios are in flight.
*/
h->cell = virt_cell;
break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio);
/*
* We complete the bio now, knowing that the bi_remaining field
* will prevent completion until the sub range discards have
* completed.
*/
bio_endio(bio);
}
static void process_discard_bio(struct thin_c *tc, struct bio *bio)
{
dm_block_t begin, end;
struct dm_cell_key virt_key;
struct dm_bio_prison_cell *virt_cell;
get_bio_block_range(tc, bio, &begin, &end);
if (begin == end) {
/*
* The discard covers less than a block.
*/
bio_endio(bio);
return;
}
build_key(tc->td, VIRTUAL, begin, end, &virt_key);
if (bio_detain(tc->pool, &virt_key, bio, &virt_cell))
/*
* Potential starvation issue: We're relying on the
* fs/application being well behaved, and not trying to
* send IO to a region at the same time as discarding it.
* If they do this persistently then it's possible this
* cell will never be granted.
*/
return;
tc->pool->process_discard_cell(tc, virt_cell);
}
static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
struct dm_cell_key *key,
struct dm_thin_lookup_result *lookup_result,
struct dm_bio_prison_cell *cell)
{
int r;
dm_block_t data_block;
struct pool *pool = tc->pool;
r = alloc_data_block(tc, &data_block);
switch (r) {
case 0:
schedule_internal_copy(tc, block, lookup_result->block,
data_block, cell, bio);
break;
case -ENOSPC:
retry_bios_on_resume(pool, cell);
break;
default:
DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
__func__, r);
cell_error(pool, cell);
break;
}
}
static void __remap_and_issue_shared_cell(void *context,
struct dm_bio_prison_cell *cell)
{
struct remap_info *info = context;
struct bio *bio;
while ((bio = bio_list_pop(&cell->bios))) {
if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) ||
bio_op(bio) == REQ_OP_DISCARD)
bio_list_add(&info->defer_bios, bio);
else {
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
inc_all_io_entry(info->tc->pool, bio);
bio_list_add(&info->issue_bios, bio);
}
}
}
static void remap_and_issue_shared_cell(struct thin_c *tc,
struct dm_bio_prison_cell *cell,
dm_block_t block)
{
struct bio *bio;
struct remap_info info;
info.tc = tc;
bio_list_init(&info.defer_bios);
bio_list_init(&info.issue_bios);
cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
&info, cell);
while ((bio = bio_list_pop(&info.defer_bios)))
thin_defer_bio(tc, bio);
while ((bio = bio_list_pop(&info.issue_bios)))
remap_and_issue(tc, bio, block);
}
static void process_shared_bio(struct thin_c *tc, struct bio *bio,
dm_block_t block,
struct dm_thin_lookup_result *lookup_result,
struct dm_bio_prison_cell *virt_cell)
{
struct dm_bio_prison_cell *data_cell;
struct pool *pool = tc->pool;
struct dm_cell_key key;
/*
* If cell is already occupied, then sharing is already in the process
* of being broken so we have nothing further to do here.
*/
build_data_key(tc->td, lookup_result->block, &key);
if (bio_detain(pool, &key, bio, &data_cell)) {
cell_defer_no_holder(tc, virt_cell);
return;
}
if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
break_sharing(tc, bio, block, &key, lookup_result, data_cell);
cell_defer_no_holder(tc, virt_cell);
} else {
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
inc_all_io_entry(pool, bio);
remap_and_issue(tc, bio, lookup_result->block);
remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
}
}
static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
struct dm_bio_prison_cell *cell)
{
int r;
dm_block_t data_block;
struct pool *pool = tc->pool;
/*
* Remap empty bios (flushes) immediately, without provisioning.
*/
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
if (!bio->bi_iter.bi_size) {
inc_all_io_entry(pool, bio);
cell_defer_no_holder(tc, cell);
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
remap_and_issue(tc, bio, 0);
return;
}
/*
* Fill read bios with zeroes and complete them immediately.
*/
if (bio_data_dir(bio) == READ) {
zero_fill_bio(bio);
cell_defer_no_holder(tc, cell);
bio_endio(bio);
return;
}
r = alloc_data_block(tc, &data_block);
switch (r) {
case 0:
if (tc->origin_dev)
schedule_external_copy(tc, block, data_block, cell, bio);
else
schedule_zero(tc, block, data_block, cell, bio);
break;
case -ENOSPC:
retry_bios_on_resume(pool, cell);
break;
default:
DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
__func__, r);
cell_error(pool, cell);
break;
}
}
static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
{
int r;
struct pool *pool = tc->pool;
struct bio *bio = cell->holder;
dm_block_t block = get_bio_block(tc, bio);
struct dm_thin_lookup_result lookup_result;
if (tc->requeue_mode) {
cell_requeue(pool, cell);
return;
}
r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
switch (r) {
case 0:
if (lookup_result.shared)
process_shared_bio(tc, bio, block, &lookup_result, cell);
else {
inc_all_io_entry(pool, bio);
remap_and_issue(tc, bio, lookup_result.block);
inc_remap_and_issue_cell(tc, cell, lookup_result.block);
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
}
break;
case -ENODATA:
if (bio_data_dir(bio) == READ && tc->origin_dev) {
inc_all_io_entry(pool, bio);
cell_defer_no_holder(tc, cell);
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
if (bio_end_sector(bio) <= tc->origin_size)
remap_to_origin_and_issue(tc, bio);
else if (bio->bi_iter.bi_sector < tc->origin_size) {
zero_fill_bio(bio);
bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
remap_to_origin_and_issue(tc, bio);
} else {
zero_fill_bio(bio);
bio_endio(bio);
}
} else
provision_block(tc, bio, block, cell);
break;
default:
DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
__func__, r);
cell_defer_no_holder(tc, cell);
bio_io_error(bio);
break;
}
}
static void process_bio(struct thin_c *tc, struct bio *bio)
{
struct pool *pool = tc->pool;
dm_block_t block = get_bio_block(tc, bio);
struct dm_bio_prison_cell *cell;
struct dm_cell_key key;
/*
* If cell is already occupied, then the block is already
* being provisioned so we have nothing further to do here.
*/
build_virtual_key(tc->td, block, &key);
if (bio_detain(pool, &key, bio, &cell))
return;
process_cell(tc, cell);
}
static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
struct dm_bio_prison_cell *cell)
{
int r;
int rw = bio_data_dir(bio);
dm_block_t block = get_bio_block(tc, bio);
struct dm_thin_lookup_result lookup_result;
r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
switch (r) {
case 0:
if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
handle_unserviceable_bio(tc->pool, bio);
if (cell)
cell_defer_no_holder(tc, cell);
} else {
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
inc_all_io_entry(tc->pool, bio);
remap_and_issue(tc, bio, lookup_result.block);
if (cell)
inc_remap_and_issue_cell(tc, cell, lookup_result.block);
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
}
break;
case -ENODATA:
if (cell)
cell_defer_no_holder(tc, cell);
if (rw != READ) {
handle_unserviceable_bio(tc->pool, bio);
break;
}
if (tc->origin_dev) {
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
inc_all_io_entry(tc->pool, bio);
remap_to_origin_and_issue(tc, bio);
break;
}
zero_fill_bio(bio);
bio_endio(bio);
break;
default:
DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
__func__, r);
if (cell)
cell_defer_no_holder(tc, cell);
bio_io_error(bio);
break;
}
}
static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
{
__process_bio_read_only(tc, bio, NULL);
}
static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
{
__process_bio_read_only(tc, cell->holder, cell);
}
static void process_bio_success(struct thin_c *tc, struct bio *bio)
{
bio_endio(bio);
}
static void process_bio_fail(struct thin_c *tc, struct bio *bio)
{
bio_io_error(bio);
}
static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
{
cell_success(tc->pool, cell);
}
static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
{
cell_error(tc->pool, cell);
}
/*
* FIXME: should we also commit due to size of transaction, measured in
* metadata blocks?
*/
static int need_commit_due_to_time(struct pool *pool)
{
return !time_in_range(jiffies, pool->last_commit_jiffies,
pool->last_commit_jiffies + COMMIT_PERIOD);
}
#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
{
struct rb_node **rbp, *parent;
struct dm_thin_endio_hook *pbd;
sector_t bi_sector = bio->bi_iter.bi_sector;
rbp = &tc->sort_bio_list.rb_node;
parent = NULL;
while (*rbp) {
parent = *rbp;
pbd = thin_pbd(parent);
if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
rbp = &(*rbp)->rb_left;
else
rbp = &(*rbp)->rb_right;
}
pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
rb_link_node(&pbd->rb_node, parent, rbp);
rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
}
static void __extract_sorted_bios(struct thin_c *tc)
{
struct rb_node *node;
struct dm_thin_endio_hook *pbd;
struct bio *bio;
for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
pbd = thin_pbd(node);
bio = thin_bio(pbd);
bio_list_add(&tc->deferred_bio_list, bio);
rb_erase(&pbd->rb_node, &tc->sort_bio_list);
}
WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
}
static void __sort_thin_deferred_bios(struct thin_c *tc)
{
struct bio *bio;
struct bio_list bios;
bio_list_init(&bios);
bio_list_merge(&bios, &tc->deferred_bio_list);
bio_list_init(&tc->deferred_bio_list);
/* Sort deferred_bio_list using rb-tree */
while ((bio = bio_list_pop(&bios)))
__thin_bio_rb_add(tc, bio);
/*
* Transfer the sorted bios in sort_bio_list back to
* deferred_bio_list to allow lockless submission of
* all bios.
*/
__extract_sorted_bios(tc);
}
static void process_thin_deferred_bios(struct thin_c *tc)
{
struct pool *pool = tc->pool;
unsigned long flags;
struct bio *bio;
struct bio_list bios;
struct blk_plug plug;
unsigned count = 0;
if (tc->requeue_mode) {
error_thin_bio_list(tc, &tc->deferred_bio_list,
BLK_STS_DM_REQUEUE);
return;
}
bio_list_init(&bios);
spin_lock_irqsave(&tc->lock, flags);
if (bio_list_empty(&tc->deferred_bio_list)) {
spin_unlock_irqrestore(&tc->lock, flags);
return;
}
__sort_thin_deferred_bios(tc);
bio_list_merge(&bios, &tc->deferred_bio_list);
bio_list_init(&tc->deferred_bio_list);
spin_unlock_irqrestore(&tc->lock, flags);
blk_start_plug(&plug);
while ((bio = bio_list_pop(&bios))) {
/*
* If we've got no free new_mapping structs, and processing
* this bio might require one, we pause until there are some
* prepared mappings to process.
*/
if (ensure_next_mapping(pool)) {
spin_lock_irqsave(&tc->lock, flags);
bio_list_add(&tc->deferred_bio_list, bio);
bio_list_merge(&tc->deferred_bio_list, &bios);
spin_unlock_irqrestore(&tc->lock, flags);
break;
}
if (bio_op(bio) == REQ_OP_DISCARD)
pool->process_discard(tc, bio);
else
pool->process_bio(tc, bio);
if ((count++ & 127) == 0) {
throttle_work_update(&pool->throttle);
dm_pool_issue_prefetches(pool->pmd);
}
}
blk_finish_plug(&plug);
}
static int cmp_cells(const void *lhs, const void *rhs)
{
struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
BUG_ON(!lhs_cell->holder);
BUG_ON(!rhs_cell->holder);
if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
return -1;
if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
return 1;
return 0;
}
static unsigned sort_cells(struct pool *pool, struct list_head *cells)
{
unsigned count = 0;
struct dm_bio_prison_cell *cell, *tmp;
list_for_each_entry_safe(cell, tmp, cells, user_list) {
if (count >= CELL_SORT_ARRAY_SIZE)
break;
pool->cell_sort_array[count++] = cell;
list_del(&cell->user_list);
}
sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
return count;
}
static void process_thin_deferred_cells(struct thin_c *tc)
{
struct pool *pool = tc->pool;
unsigned long flags;
struct list_head cells;
struct dm_bio_prison_cell *cell;
unsigned i, j, count;
INIT_LIST_HEAD(&cells);
spin_lock_irqsave(&tc->lock, flags);
list_splice_init(&tc->deferred_cells, &cells);
spin_unlock_irqrestore(&tc->lock, flags);
if (list_empty(&cells))
return;
do {
count = sort_cells(tc->pool, &cells);
for (i = 0; i < count; i++) {
cell = pool->cell_sort_array[i];
BUG_ON(!cell->holder);
/*
* If we've got no free new_mapping structs, and processing
* this bio might require one, we pause until there are some
* prepared mappings to process.
*/
if (ensure_next_mapping(pool)) {
for (j = i; j < count; j++)
list_add(&pool->cell_sort_array[j]->user_list, &cells);
spin_lock_irqsave(&tc->lock, flags);
list_splice(&cells, &tc->deferred_cells);
spin_unlock_irqrestore(&tc->lock, flags);
return;
}
if (bio_op(cell->holder) == REQ_OP_DISCARD)
pool->process_discard_cell(tc, cell);
else
pool->process_cell(tc, cell);
}
} while (!list_empty(&cells));
}
dm thin: fix rcu_read_lock being held in code that can sleep Commit c140e1c4e23 ("dm thin: use per thin device deferred bio lists") introduced the use of an rculist for all active thin devices. The use of rcu_read_lock() in process_deferred_bios() can result in a BUG if a dm_bio_prison_cell must be allocated as a side-effect of bio_detain(): BUG: sleeping function called from invalid context at mm/mempool.c:203 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u8:0 3 locks held by kworker/u8:0/6: #0: ("dm-" "thin"){.+.+..}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #1: ((&pool->worker)){+.+...}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #2: (rcu_read_lock){.+.+..}, at: [<ffffffff816360b5>] do_worker+0x5/0x4d0 We can't process deferred bios with the rcu lock held, since dm_bio_prison_cell allocation may block if the bio-prison's cell mempool is exhausted. To fix: - Introduce a refcount and completion field to each thin_c - Add thin_get/put methods for adjusting the refcount. If the refcount hits zero then the completion is triggered. - Initialise refcount to 1 when creating thin_c - When iterating the active_thins list we thin_get() whilst the rcu lock is held. - After the rcu lock is dropped we process the deferred bios for that thin. - When destroying a thin_c we thin_put() and then wait for the completion -- to avoid a race between the worker thread iterating from that thin_c and destroying the thin_c. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-04-08 10:29:01 +00:00
static void thin_get(struct thin_c *tc);
static void thin_put(struct thin_c *tc);
/*
* We can't hold rcu_read_lock() around code that can block. So we
* find a thin with the rcu lock held; bump a refcount; then drop
* the lock.
*/
static struct thin_c *get_first_thin(struct pool *pool)
{
struct thin_c *tc = NULL;
rcu_read_lock();
if (!list_empty(&pool->active_thins)) {
tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
thin_get(tc);
}
rcu_read_unlock();
return tc;
}
static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
{
struct thin_c *old_tc = tc;
rcu_read_lock();
list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
thin_get(tc);
thin_put(old_tc);
rcu_read_unlock();
return tc;
}
thin_put(old_tc);
rcu_read_unlock();
return NULL;
}
static void process_deferred_bios(struct pool *pool)
{
unsigned long flags;
struct bio *bio;
struct bio_list bios;
struct thin_c *tc;
dm thin: fix rcu_read_lock being held in code that can sleep Commit c140e1c4e23 ("dm thin: use per thin device deferred bio lists") introduced the use of an rculist for all active thin devices. The use of rcu_read_lock() in process_deferred_bios() can result in a BUG if a dm_bio_prison_cell must be allocated as a side-effect of bio_detain(): BUG: sleeping function called from invalid context at mm/mempool.c:203 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u8:0 3 locks held by kworker/u8:0/6: #0: ("dm-" "thin"){.+.+..}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #1: ((&pool->worker)){+.+...}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #2: (rcu_read_lock){.+.+..}, at: [<ffffffff816360b5>] do_worker+0x5/0x4d0 We can't process deferred bios with the rcu lock held, since dm_bio_prison_cell allocation may block if the bio-prison's cell mempool is exhausted. To fix: - Introduce a refcount and completion field to each thin_c - Add thin_get/put methods for adjusting the refcount. If the refcount hits zero then the completion is triggered. - Initialise refcount to 1 when creating thin_c - When iterating the active_thins list we thin_get() whilst the rcu lock is held. - After the rcu lock is dropped we process the deferred bios for that thin. - When destroying a thin_c we thin_put() and then wait for the completion -- to avoid a race between the worker thread iterating from that thin_c and destroying the thin_c. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-04-08 10:29:01 +00:00
tc = get_first_thin(pool);
while (tc) {
process_thin_deferred_cells(tc);
process_thin_deferred_bios(tc);
dm thin: fix rcu_read_lock being held in code that can sleep Commit c140e1c4e23 ("dm thin: use per thin device deferred bio lists") introduced the use of an rculist for all active thin devices. The use of rcu_read_lock() in process_deferred_bios() can result in a BUG if a dm_bio_prison_cell must be allocated as a side-effect of bio_detain(): BUG: sleeping function called from invalid context at mm/mempool.c:203 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u8:0 3 locks held by kworker/u8:0/6: #0: ("dm-" "thin"){.+.+..}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #1: ((&pool->worker)){+.+...}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #2: (rcu_read_lock){.+.+..}, at: [<ffffffff816360b5>] do_worker+0x5/0x4d0 We can't process deferred bios with the rcu lock held, since dm_bio_prison_cell allocation may block if the bio-prison's cell mempool is exhausted. To fix: - Introduce a refcount and completion field to each thin_c - Add thin_get/put methods for adjusting the refcount. If the refcount hits zero then the completion is triggered. - Initialise refcount to 1 when creating thin_c - When iterating the active_thins list we thin_get() whilst the rcu lock is held. - After the rcu lock is dropped we process the deferred bios for that thin. - When destroying a thin_c we thin_put() and then wait for the completion -- to avoid a race between the worker thread iterating from that thin_c and destroying the thin_c. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-04-08 10:29:01 +00:00
tc = get_next_thin(pool, tc);
}
/*
* If there are any deferred flush bios, we must commit
* the metadata before issuing them.
*/
bio_list_init(&bios);
spin_lock_irqsave(&pool->lock, flags);
bio_list_merge(&bios, &pool->deferred_flush_bios);
bio_list_init(&pool->deferred_flush_bios);
spin_unlock_irqrestore(&pool->lock, flags);
if (bio_list_empty(&bios) &&
!(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
return;
if (commit(pool)) {
while ((bio = bio_list_pop(&bios)))
bio_io_error(bio);
return;
}
pool->last_commit_jiffies = jiffies;
while ((bio = bio_list_pop(&bios)))
generic_make_request(bio);
}
static void do_worker(struct work_struct *ws)
{
struct pool *pool = container_of(ws, struct pool, worker);
throttle_work_start(&pool->throttle);
dm_pool_issue_prefetches(pool->pmd);
throttle_work_update(&pool->throttle);
process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
throttle_work_update(&pool->throttle);
process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
throttle_work_update(&pool->throttle);
process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2);
throttle_work_update(&pool->throttle);
process_deferred_bios(pool);
throttle_work_complete(&pool->throttle);
}
/*
* We want to commit periodically so that not too much
* unwritten data builds up.
*/
static void do_waker(struct work_struct *ws)
{
struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
wake_worker(pool);
queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
}
static void notify_of_pool_mode_change_to_oods(struct pool *pool);
/*
* We're holding onto IO to allow userland time to react. After the
* timeout either the pool will have been resized (and thus back in
* PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space.
*/
static void do_no_space_timeout(struct work_struct *ws)
{
struct pool *pool = container_of(to_delayed_work(ws), struct pool,
no_space_timeout);
if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
pool->pf.error_if_no_space = true;
notify_of_pool_mode_change_to_oods(pool);
error_retry_list_with_code(pool, BLK_STS_NOSPC);
}
}
/*----------------------------------------------------------------*/
struct pool_work {
struct work_struct worker;
struct completion complete;
};
static struct pool_work *to_pool_work(struct work_struct *ws)
{
return container_of(ws, struct pool_work, worker);
}
static void pool_work_complete(struct pool_work *pw)
{
complete(&pw->complete);
}
static void pool_work_wait(struct pool_work *pw, struct pool *pool,
void (*fn)(struct work_struct *))
{
INIT_WORK_ONSTACK(&pw->worker, fn);
init_completion(&pw->complete);
queue_work(pool->wq, &pw->worker);
wait_for_completion(&pw->complete);
}
/*----------------------------------------------------------------*/
struct noflush_work {
struct pool_work pw;
struct thin_c *tc;
};
static struct noflush_work *to_noflush(struct work_struct *ws)
{
return container_of(to_pool_work(ws), struct noflush_work, pw);
}
static void do_noflush_start(struct work_struct *ws)
{
struct noflush_work *w = to_noflush(ws);
w->tc->requeue_mode = true;
requeue_io(w->tc);
pool_work_complete(&w->pw);
}
static void do_noflush_stop(struct work_struct *ws)
{
struct noflush_work *w = to_noflush(ws);
w->tc->requeue_mode = false;
pool_work_complete(&w->pw);
}
static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
{
struct noflush_work w;
w.tc = tc;
pool_work_wait(&w.pw, tc->pool, fn);
}
/*----------------------------------------------------------------*/
static enum pool_mode get_pool_mode(struct pool *pool)
{
return pool->pf.mode;
}
static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
{
dm_table_event(pool->ti->table);
DMINFO("%s: switching pool to %s mode",
dm_device_name(pool->pool_md), new_mode);
}
static void notify_of_pool_mode_change_to_oods(struct pool *pool)
{
if (!pool->pf.error_if_no_space)
notify_of_pool_mode_change(pool, "out-of-data-space (queue IO)");
else
notify_of_pool_mode_change(pool, "out-of-data-space (error IO)");
}
static bool passdown_enabled(struct pool_c *pt)
{
return pt->adjusted_pf.discard_passdown;
}
static void set_discard_callbacks(struct pool *pool)
{
struct pool_c *pt = pool->ti->private;
if (passdown_enabled(pt)) {
pool->process_discard_cell = process_discard_cell_passdown;
pool->process_prepared_discard = process_prepared_discard_passdown_pt1;
pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2;
} else {
pool->process_discard_cell = process_discard_cell_no_passdown;
pool->process_prepared_discard = process_prepared_discard_no_passdown;
}
}
dm thin: fix set_pool_mode exposed pool operation races The pool mode must not be switched until after the corresponding pool process_* methods have been established. Otherwise, because set_pool_mode() isn't interlocked with the IO path for performance reasons, the IO path can end up executing process_* operations that don't match the mode. This patch eliminates problems like the following (as seen on really fast PCIe SSD storage when transitioning the pool's mode from PM_READ_ONLY to PM_WRITE): kernel: device-mapper: thin: 253:2: reached low water mark for data device: sending event. kernel: device-mapper: thin: 253:2: no free data space available. kernel: device-mapper: thin: 253:2: switching pool to read-only mode kernel: device-mapper: thin: 253:2: switching pool to write mode kernel: ------------[ cut here ]------------ kernel: WARNING: CPU: 11 PID: 7564 at drivers/md/dm-thin.c:995 handle_unserviceable_bio+0x146/0x160 [dm_thin_pool]() ... kernel: Workqueue: dm-thin do_worker [dm_thin_pool] kernel: 00000000000003e3 ffff880308831cc8 ffffffff8152ebcb 00000000000003e3 kernel: 0000000000000000 ffff880308831d08 ffffffff8104c46c ffff88032502a800 kernel: ffff880036409000 ffff88030ec7ce00 0000000000000001 00000000ffffffc3 kernel: Call Trace: kernel: [<ffffffff8152ebcb>] dump_stack+0x49/0x5e kernel: [<ffffffff8104c46c>] warn_slowpath_common+0x8c/0xc0 kernel: [<ffffffff8104c4ba>] warn_slowpath_null+0x1a/0x20 kernel: [<ffffffffa001e2c6>] handle_unserviceable_bio+0x146/0x160 [dm_thin_pool] kernel: [<ffffffffa001f276>] process_bio_read_only+0x136/0x180 [dm_thin_pool] kernel: [<ffffffffa0020b75>] process_deferred_bios+0xc5/0x230 [dm_thin_pool] kernel: [<ffffffffa0020d31>] do_worker+0x51/0x60 [dm_thin_pool] kernel: [<ffffffff81067823>] process_one_work+0x183/0x490 kernel: [<ffffffff81068c70>] worker_thread+0x120/0x3a0 kernel: [<ffffffff81068b50>] ? manage_workers+0x160/0x160 kernel: [<ffffffff8106e86e>] kthread+0xce/0xf0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: [<ffffffff8153b3ec>] ret_from_fork+0x7c/0xb0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: ---[ end trace 3f00528e08ffa55c ]--- kernel: device-mapper: thin: pool mode is PM_WRITE not PM_READ_ONLY like expected!? dm-thin.c:995 was the WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY); at the top of handle_unserviceable_bio(). And as the additional debugging I had conveys: the pool mode was _not_ PM_READ_ONLY like expected, it was already PM_WRITE, yet pool->process_bio was still set to process_bio_read_only(). Also, while fixing this up, reduce logging of redundant pool mode transitions by checking new_mode is different from old_mode. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2013-12-20 19:27:28 +00:00
static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
{
struct pool_c *pt = pool->ti->private;
bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
enum pool_mode old_mode = get_pool_mode(pool);
locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-23 21:07:29 +00:00
unsigned long no_space_timeout = READ_ONCE(no_space_timeout_secs) * HZ;
/*
* Never allow the pool to transition to PM_WRITE mode if user
* intervention is required to verify metadata and data consistency.
*/
if (new_mode == PM_WRITE && needs_check) {
DMERR("%s: unable to switch pool to write mode until repaired.",
dm_device_name(pool->pool_md));
if (old_mode != new_mode)
new_mode = old_mode;
else
new_mode = PM_READ_ONLY;
}
/*
* If we were in PM_FAIL mode, rollback of metadata failed. We're
* not going to recover without a thin_repair. So we never let the
* pool move out of the old mode.
*/
if (old_mode == PM_FAIL)
new_mode = old_mode;
dm thin: fix set_pool_mode exposed pool operation races The pool mode must not be switched until after the corresponding pool process_* methods have been established. Otherwise, because set_pool_mode() isn't interlocked with the IO path for performance reasons, the IO path can end up executing process_* operations that don't match the mode. This patch eliminates problems like the following (as seen on really fast PCIe SSD storage when transitioning the pool's mode from PM_READ_ONLY to PM_WRITE): kernel: device-mapper: thin: 253:2: reached low water mark for data device: sending event. kernel: device-mapper: thin: 253:2: no free data space available. kernel: device-mapper: thin: 253:2: switching pool to read-only mode kernel: device-mapper: thin: 253:2: switching pool to write mode kernel: ------------[ cut here ]------------ kernel: WARNING: CPU: 11 PID: 7564 at drivers/md/dm-thin.c:995 handle_unserviceable_bio+0x146/0x160 [dm_thin_pool]() ... kernel: Workqueue: dm-thin do_worker [dm_thin_pool] kernel: 00000000000003e3 ffff880308831cc8 ffffffff8152ebcb 00000000000003e3 kernel: 0000000000000000 ffff880308831d08 ffffffff8104c46c ffff88032502a800 kernel: ffff880036409000 ffff88030ec7ce00 0000000000000001 00000000ffffffc3 kernel: Call Trace: kernel: [<ffffffff8152ebcb>] dump_stack+0x49/0x5e kernel: [<ffffffff8104c46c>] warn_slowpath_common+0x8c/0xc0 kernel: [<ffffffff8104c4ba>] warn_slowpath_null+0x1a/0x20 kernel: [<ffffffffa001e2c6>] handle_unserviceable_bio+0x146/0x160 [dm_thin_pool] kernel: [<ffffffffa001f276>] process_bio_read_only+0x136/0x180 [dm_thin_pool] kernel: [<ffffffffa0020b75>] process_deferred_bios+0xc5/0x230 [dm_thin_pool] kernel: [<ffffffffa0020d31>] do_worker+0x51/0x60 [dm_thin_pool] kernel: [<ffffffff81067823>] process_one_work+0x183/0x490 kernel: [<ffffffff81068c70>] worker_thread+0x120/0x3a0 kernel: [<ffffffff81068b50>] ? manage_workers+0x160/0x160 kernel: [<ffffffff8106e86e>] kthread+0xce/0xf0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: [<ffffffff8153b3ec>] ret_from_fork+0x7c/0xb0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: ---[ end trace 3f00528e08ffa55c ]--- kernel: device-mapper: thin: pool mode is PM_WRITE not PM_READ_ONLY like expected!? dm-thin.c:995 was the WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY); at the top of handle_unserviceable_bio(). And as the additional debugging I had conveys: the pool mode was _not_ PM_READ_ONLY like expected, it was already PM_WRITE, yet pool->process_bio was still set to process_bio_read_only(). Also, while fixing this up, reduce logging of redundant pool mode transitions by checking new_mode is different from old_mode. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2013-12-20 19:27:28 +00:00
switch (new_mode) {
case PM_FAIL:
dm thin: fix set_pool_mode exposed pool operation races The pool mode must not be switched until after the corresponding pool process_* methods have been established. Otherwise, because set_pool_mode() isn't interlocked with the IO path for performance reasons, the IO path can end up executing process_* operations that don't match the mode. This patch eliminates problems like the following (as seen on really fast PCIe SSD storage when transitioning the pool's mode from PM_READ_ONLY to PM_WRITE): kernel: device-mapper: thin: 253:2: reached low water mark for data device: sending event. kernel: device-mapper: thin: 253:2: no free data space available. kernel: device-mapper: thin: 253:2: switching pool to read-only mode kernel: device-mapper: thin: 253:2: switching pool to write mode kernel: ------------[ cut here ]------------ kernel: WARNING: CPU: 11 PID: 7564 at drivers/md/dm-thin.c:995 handle_unserviceable_bio+0x146/0x160 [dm_thin_pool]() ... kernel: Workqueue: dm-thin do_worker [dm_thin_pool] kernel: 00000000000003e3 ffff880308831cc8 ffffffff8152ebcb 00000000000003e3 kernel: 0000000000000000 ffff880308831d08 ffffffff8104c46c ffff88032502a800 kernel: ffff880036409000 ffff88030ec7ce00 0000000000000001 00000000ffffffc3 kernel: Call Trace: kernel: [<ffffffff8152ebcb>] dump_stack+0x49/0x5e kernel: [<ffffffff8104c46c>] warn_slowpath_common+0x8c/0xc0 kernel: [<ffffffff8104c4ba>] warn_slowpath_null+0x1a/0x20 kernel: [<ffffffffa001e2c6>] handle_unserviceable_bio+0x146/0x160 [dm_thin_pool] kernel: [<ffffffffa001f276>] process_bio_read_only+0x136/0x180 [dm_thin_pool] kernel: [<ffffffffa0020b75>] process_deferred_bios+0xc5/0x230 [dm_thin_pool] kernel: [<ffffffffa0020d31>] do_worker+0x51/0x60 [dm_thin_pool] kernel: [<ffffffff81067823>] process_one_work+0x183/0x490 kernel: [<ffffffff81068c70>] worker_thread+0x120/0x3a0 kernel: [<ffffffff81068b50>] ? manage_workers+0x160/0x160 kernel: [<ffffffff8106e86e>] kthread+0xce/0xf0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: [<ffffffff8153b3ec>] ret_from_fork+0x7c/0xb0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: ---[ end trace 3f00528e08ffa55c ]--- kernel: device-mapper: thin: pool mode is PM_WRITE not PM_READ_ONLY like expected!? dm-thin.c:995 was the WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY); at the top of handle_unserviceable_bio(). And as the additional debugging I had conveys: the pool mode was _not_ PM_READ_ONLY like expected, it was already PM_WRITE, yet pool->process_bio was still set to process_bio_read_only(). Also, while fixing this up, reduce logging of redundant pool mode transitions by checking new_mode is different from old_mode. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2013-12-20 19:27:28 +00:00
if (old_mode != new_mode)
notify_of_pool_mode_change(pool, "failure");
dm_pool_metadata_read_only(pool->pmd);
pool->process_bio = process_bio_fail;
pool->process_discard = process_bio_fail;
pool->process_cell = process_cell_fail;
pool->process_discard_cell = process_cell_fail;
pool->process_prepared_mapping = process_prepared_mapping_fail;
pool->process_prepared_discard = process_prepared_discard_fail;
error_retry_list(pool);
break;
case PM_READ_ONLY:
dm thin: fix set_pool_mode exposed pool operation races The pool mode must not be switched until after the corresponding pool process_* methods have been established. Otherwise, because set_pool_mode() isn't interlocked with the IO path for performance reasons, the IO path can end up executing process_* operations that don't match the mode. This patch eliminates problems like the following (as seen on really fast PCIe SSD storage when transitioning the pool's mode from PM_READ_ONLY to PM_WRITE): kernel: device-mapper: thin: 253:2: reached low water mark for data device: sending event. kernel: device-mapper: thin: 253:2: no free data space available. kernel: device-mapper: thin: 253:2: switching pool to read-only mode kernel: device-mapper: thin: 253:2: switching pool to write mode kernel: ------------[ cut here ]------------ kernel: WARNING: CPU: 11 PID: 7564 at drivers/md/dm-thin.c:995 handle_unserviceable_bio+0x146/0x160 [dm_thin_pool]() ... kernel: Workqueue: dm-thin do_worker [dm_thin_pool] kernel: 00000000000003e3 ffff880308831cc8 ffffffff8152ebcb 00000000000003e3 kernel: 0000000000000000 ffff880308831d08 ffffffff8104c46c ffff88032502a800 kernel: ffff880036409000 ffff88030ec7ce00 0000000000000001 00000000ffffffc3 kernel: Call Trace: kernel: [<ffffffff8152ebcb>] dump_stack+0x49/0x5e kernel: [<ffffffff8104c46c>] warn_slowpath_common+0x8c/0xc0 kernel: [<ffffffff8104c4ba>] warn_slowpath_null+0x1a/0x20 kernel: [<ffffffffa001e2c6>] handle_unserviceable_bio+0x146/0x160 [dm_thin_pool] kernel: [<ffffffffa001f276>] process_bio_read_only+0x136/0x180 [dm_thin_pool] kernel: [<ffffffffa0020b75>] process_deferred_bios+0xc5/0x230 [dm_thin_pool] kernel: [<ffffffffa0020d31>] do_worker+0x51/0x60 [dm_thin_pool] kernel: [<ffffffff81067823>] process_one_work+0x183/0x490 kernel: [<ffffffff81068c70>] worker_thread+0x120/0x3a0 kernel: [<ffffffff81068b50>] ? manage_workers+0x160/0x160 kernel: [<ffffffff8106e86e>] kthread+0xce/0xf0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: [<ffffffff8153b3ec>] ret_from_fork+0x7c/0xb0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: ---[ end trace 3f00528e08ffa55c ]--- kernel: device-mapper: thin: pool mode is PM_WRITE not PM_READ_ONLY like expected!? dm-thin.c:995 was the WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY); at the top of handle_unserviceable_bio(). And as the additional debugging I had conveys: the pool mode was _not_ PM_READ_ONLY like expected, it was already PM_WRITE, yet pool->process_bio was still set to process_bio_read_only(). Also, while fixing this up, reduce logging of redundant pool mode transitions by checking new_mode is different from old_mode. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2013-12-20 19:27:28 +00:00
if (old_mode != new_mode)
notify_of_pool_mode_change(pool, "read-only");
dm_pool_metadata_read_only(pool->pmd);
pool->process_bio = process_bio_read_only;
pool->process_discard = process_bio_success;
pool->process_cell = process_cell_read_only;
pool->process_discard_cell = process_cell_success;
pool->process_prepared_mapping = process_prepared_mapping_fail;
pool->process_prepared_discard = process_prepared_discard_success;
error_retry_list(pool);
break;
case PM_OUT_OF_DATA_SPACE:
/*
* Ideally we'd never hit this state; the low water mark
* would trigger userland to extend the pool before we
* completely run out of data space. However, many small
* IOs to unprovisioned space can consume data space at an
* alarming rate. Adjust your low water mark if you're
* frequently seeing this mode.
*/
if (old_mode != new_mode)
notify_of_pool_mode_change_to_oods(pool);
pool->out_of_data_space = true;
pool->process_bio = process_bio_read_only;
pool->process_discard = process_discard_bio;
pool->process_cell = process_cell_read_only;
pool->process_prepared_mapping = process_prepared_mapping;
set_discard_callbacks(pool);
if (!pool->pf.error_if_no_space && no_space_timeout)
queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
break;
case PM_WRITE:
dm thin: fix set_pool_mode exposed pool operation races The pool mode must not be switched until after the corresponding pool process_* methods have been established. Otherwise, because set_pool_mode() isn't interlocked with the IO path for performance reasons, the IO path can end up executing process_* operations that don't match the mode. This patch eliminates problems like the following (as seen on really fast PCIe SSD storage when transitioning the pool's mode from PM_READ_ONLY to PM_WRITE): kernel: device-mapper: thin: 253:2: reached low water mark for data device: sending event. kernel: device-mapper: thin: 253:2: no free data space available. kernel: device-mapper: thin: 253:2: switching pool to read-only mode kernel: device-mapper: thin: 253:2: switching pool to write mode kernel: ------------[ cut here ]------------ kernel: WARNING: CPU: 11 PID: 7564 at drivers/md/dm-thin.c:995 handle_unserviceable_bio+0x146/0x160 [dm_thin_pool]() ... kernel: Workqueue: dm-thin do_worker [dm_thin_pool] kernel: 00000000000003e3 ffff880308831cc8 ffffffff8152ebcb 00000000000003e3 kernel: 0000000000000000 ffff880308831d08 ffffffff8104c46c ffff88032502a800 kernel: ffff880036409000 ffff88030ec7ce00 0000000000000001 00000000ffffffc3 kernel: Call Trace: kernel: [<ffffffff8152ebcb>] dump_stack+0x49/0x5e kernel: [<ffffffff8104c46c>] warn_slowpath_common+0x8c/0xc0 kernel: [<ffffffff8104c4ba>] warn_slowpath_null+0x1a/0x20 kernel: [<ffffffffa001e2c6>] handle_unserviceable_bio+0x146/0x160 [dm_thin_pool] kernel: [<ffffffffa001f276>] process_bio_read_only+0x136/0x180 [dm_thin_pool] kernel: [<ffffffffa0020b75>] process_deferred_bios+0xc5/0x230 [dm_thin_pool] kernel: [<ffffffffa0020d31>] do_worker+0x51/0x60 [dm_thin_pool] kernel: [<ffffffff81067823>] process_one_work+0x183/0x490 kernel: [<ffffffff81068c70>] worker_thread+0x120/0x3a0 kernel: [<ffffffff81068b50>] ? manage_workers+0x160/0x160 kernel: [<ffffffff8106e86e>] kthread+0xce/0xf0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: [<ffffffff8153b3ec>] ret_from_fork+0x7c/0xb0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: ---[ end trace 3f00528e08ffa55c ]--- kernel: device-mapper: thin: pool mode is PM_WRITE not PM_READ_ONLY like expected!? dm-thin.c:995 was the WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY); at the top of handle_unserviceable_bio(). And as the additional debugging I had conveys: the pool mode was _not_ PM_READ_ONLY like expected, it was already PM_WRITE, yet pool->process_bio was still set to process_bio_read_only(). Also, while fixing this up, reduce logging of redundant pool mode transitions by checking new_mode is different from old_mode. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2013-12-20 19:27:28 +00:00
if (old_mode != new_mode)
notify_of_pool_mode_change(pool, "write");
pool->out_of_data_space = false;
pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
dm_pool_metadata_read_write(pool->pmd);
pool->process_bio = process_bio;
pool->process_discard = process_discard_bio;
pool->process_cell = process_cell;
pool->process_prepared_mapping = process_prepared_mapping;
set_discard_callbacks(pool);
break;
}
dm thin: fix set_pool_mode exposed pool operation races The pool mode must not be switched until after the corresponding pool process_* methods have been established. Otherwise, because set_pool_mode() isn't interlocked with the IO path for performance reasons, the IO path can end up executing process_* operations that don't match the mode. This patch eliminates problems like the following (as seen on really fast PCIe SSD storage when transitioning the pool's mode from PM_READ_ONLY to PM_WRITE): kernel: device-mapper: thin: 253:2: reached low water mark for data device: sending event. kernel: device-mapper: thin: 253:2: no free data space available. kernel: device-mapper: thin: 253:2: switching pool to read-only mode kernel: device-mapper: thin: 253:2: switching pool to write mode kernel: ------------[ cut here ]------------ kernel: WARNING: CPU: 11 PID: 7564 at drivers/md/dm-thin.c:995 handle_unserviceable_bio+0x146/0x160 [dm_thin_pool]() ... kernel: Workqueue: dm-thin do_worker [dm_thin_pool] kernel: 00000000000003e3 ffff880308831cc8 ffffffff8152ebcb 00000000000003e3 kernel: 0000000000000000 ffff880308831d08 ffffffff8104c46c ffff88032502a800 kernel: ffff880036409000 ffff88030ec7ce00 0000000000000001 00000000ffffffc3 kernel: Call Trace: kernel: [<ffffffff8152ebcb>] dump_stack+0x49/0x5e kernel: [<ffffffff8104c46c>] warn_slowpath_common+0x8c/0xc0 kernel: [<ffffffff8104c4ba>] warn_slowpath_null+0x1a/0x20 kernel: [<ffffffffa001e2c6>] handle_unserviceable_bio+0x146/0x160 [dm_thin_pool] kernel: [<ffffffffa001f276>] process_bio_read_only+0x136/0x180 [dm_thin_pool] kernel: [<ffffffffa0020b75>] process_deferred_bios+0xc5/0x230 [dm_thin_pool] kernel: [<ffffffffa0020d31>] do_worker+0x51/0x60 [dm_thin_pool] kernel: [<ffffffff81067823>] process_one_work+0x183/0x490 kernel: [<ffffffff81068c70>] worker_thread+0x120/0x3a0 kernel: [<ffffffff81068b50>] ? manage_workers+0x160/0x160 kernel: [<ffffffff8106e86e>] kthread+0xce/0xf0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: [<ffffffff8153b3ec>] ret_from_fork+0x7c/0xb0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: ---[ end trace 3f00528e08ffa55c ]--- kernel: device-mapper: thin: pool mode is PM_WRITE not PM_READ_ONLY like expected!? dm-thin.c:995 was the WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY); at the top of handle_unserviceable_bio(). And as the additional debugging I had conveys: the pool mode was _not_ PM_READ_ONLY like expected, it was already PM_WRITE, yet pool->process_bio was still set to process_bio_read_only(). Also, while fixing this up, reduce logging of redundant pool mode transitions by checking new_mode is different from old_mode. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2013-12-20 19:27:28 +00:00
pool->pf.mode = new_mode;
/*
* The pool mode may have changed, sync it so bind_control_target()
* doesn't cause an unexpected mode transition on resume.
*/
pt->adjusted_pf.mode = new_mode;
}
static void abort_transaction(struct pool *pool)
{
const char *dev_name = dm_device_name(pool->pool_md);
DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
if (dm_pool_abort_metadata(pool->pmd)) {
DMERR("%s: failed to abort metadata transaction", dev_name);
set_pool_mode(pool, PM_FAIL);
}
if (dm_pool_metadata_set_needs_check(pool->pmd)) {
DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
set_pool_mode(pool, PM_FAIL);
}
}
static void metadata_operation_failed(struct pool *pool, const char *op, int r)
{
DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
dm_device_name(pool->pool_md), op, r);
abort_transaction(pool);
set_pool_mode(pool, PM_READ_ONLY);
}
/*----------------------------------------------------------------*/
/*
* Mapping functions.
*/
/*
* Called only while mapping a thin bio to hand it over to the workqueue.
*/
static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
{
unsigned long flags;
struct pool *pool = tc->pool;
spin_lock_irqsave(&tc->lock, flags);
bio_list_add(&tc->deferred_bio_list, bio);
spin_unlock_irqrestore(&tc->lock, flags);
wake_worker(pool);
}
static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
{
struct pool *pool = tc->pool;
throttle_lock(&pool->throttle);
thin_defer_bio(tc, bio);
throttle_unlock(&pool->throttle);
}
static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
{
unsigned long flags;
struct pool *pool = tc->pool;
throttle_lock(&pool->throttle);
spin_lock_irqsave(&tc->lock, flags);
list_add_tail(&cell->user_list, &tc->deferred_cells);
spin_unlock_irqrestore(&tc->lock, flags);
throttle_unlock(&pool->throttle);
wake_worker(pool);
}
static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
{
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
h->tc = tc;
h->shared_read_entry = NULL;
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
h->all_io_entry = NULL;
h->overwrite_mapping = NULL;
h->cell = NULL;
}
/*
* Non-blocking function called from the thin target's map function.
*/
static int thin_bio_map(struct dm_target *ti, struct bio *bio)
{
int r;
struct thin_c *tc = ti->private;
dm_block_t block = get_bio_block(tc, bio);
struct dm_thin_device *td = tc->td;
struct dm_thin_lookup_result result;
struct dm_bio_prison_cell *virt_cell, *data_cell;
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
struct dm_cell_key key;
thin_hook_bio(tc, bio);
if (tc->requeue_mode) {
bio->bi_status = BLK_STS_DM_REQUEUE;
bio_endio(bio);
return DM_MAPIO_SUBMITTED;
}
if (get_pool_mode(tc->pool) == PM_FAIL) {
bio_io_error(bio);
return DM_MAPIO_SUBMITTED;
}
if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) {
thin_defer_bio_with_throttle(tc, bio);
return DM_MAPIO_SUBMITTED;
}
/*
* We must hold the virtual cell before doing the lookup, otherwise
* there's a race with discard.
*/
build_virtual_key(tc->td, block, &key);
if (bio_detain(tc->pool, &key, bio, &virt_cell))
return DM_MAPIO_SUBMITTED;
r = dm_thin_find_block(td, block, 0, &result);
/*
* Note that we defer readahead too.
*/
switch (r) {
case 0:
if (unlikely(result.shared)) {
/*
* We have a race condition here between the
* result.shared value returned by the lookup and
* snapshot creation, which may cause new
* sharing.
*
* To avoid this always quiesce the origin before
* taking the snap. You want to do this anyway to
* ensure a consistent application view
* (i.e. lockfs).
*
* More distant ancestors are irrelevant. The
* shared flag will be set in their case.
*/
thin_defer_cell(tc, virt_cell);
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
return DM_MAPIO_SUBMITTED;
}
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
build_data_key(tc->td, result.block, &key);
if (bio_detain(tc->pool, &key, bio, &data_cell)) {
cell_defer_no_holder(tc, virt_cell);
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
return DM_MAPIO_SUBMITTED;
}
inc_all_io_entry(tc->pool, bio);
cell_defer_no_holder(tc, data_cell);
cell_defer_no_holder(tc, virt_cell);
dm thin: fix race between simultaneous io and discards to same block There is a race when discard bios and non-discard bios are issued simultaneously to the same block. Discard support is expensive for all thin devices precisely because you have to be careful to quiesce the area you're discarding. DM thin must handle this conflicting IO pattern (simultaneous non-discard vs discard) even though a sane application shouldn't be issuing such IO. The race manifests as follows: 1. A non-discard bio is mapped in thin_bio_map. This doesn't lock out parallel activity to the same block. 2. A discard bio is issued to the same block as the non-discard bio. 3. The discard bio is locked in a dm_bio_prison_cell in process_discard to lock out parallel activity against the same block. 4. The non-discard bio's mapping continues and its all_io_entry is incremented so the bio is accounted for in the thin pool's all_io_ds which is a dm_deferred_set used to track time locality of non-discard IO. 5. The non-discard bio is finally locked in a dm_bio_prison_cell in process_bio. The race can result in deadlock, leaving the block layer hanging waiting for completion of a discard bio that never completes, e.g.: INFO: task ruby:15354 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ruby D ffffffff8160f0e0 0 15354 15314 0x00000000 ffff8802fb08bc58 0000000000000082 ffff8802fb08bfd8 0000000000012900 ffff8802fb08a010 0000000000012900 0000000000012900 0000000000012900 ffff8802fb08bfd8 0000000000012900 ffff8803324b9480 ffff88032c6f14c0 Call Trace: [<ffffffff814e5a19>] schedule+0x29/0x70 [<ffffffff814e3d85>] schedule_timeout+0x195/0x220 [<ffffffffa06b9bc1>] ? _dm_request+0x111/0x160 [dm_mod] [<ffffffff814e589e>] wait_for_common+0x11e/0x190 [<ffffffff8107a170>] ? try_to_wake_up+0x2b0/0x2b0 [<ffffffff814e59ed>] wait_for_completion+0x1d/0x20 [<ffffffff81233289>] blkdev_issue_discard+0x219/0x260 [<ffffffff81233e79>] blkdev_ioctl+0x6e9/0x7b0 [<ffffffff8119a65c>] block_ioctl+0x3c/0x40 [<ffffffff8117539c>] do_vfs_ioctl+0x8c/0x340 [<ffffffff8119a547>] ? block_llseek+0x67/0xb0 [<ffffffff811756f1>] sys_ioctl+0xa1/0xb0 [<ffffffff810561f6>] ? sys_rt_sigprocmask+0x86/0xd0 [<ffffffff814ef099>] system_call_fastpath+0x16/0x1b The thinp-test-suite's test_discard_random_sectors reliably hits this deadlock on fast SSD storage. The fix for this race is that the all_io_entry for a bio must be incremented whilst the dm_bio_prison_cell is held for the bio's associated virtual and physical blocks. That cell locking wasn't occurring early enough in thin_bio_map. This patch fixes this. Care is taken to always call the new function inc_all_io_entry() with the relevant cells locked, but they are generally unlocked before calling issue() to try to avoid holding the cells locked across generic_submit_request. Also, now that thin_bio_map may lock bios in a cell, process_bio() is no longer the only thread that will do so. Because of this we must be sure to use cell_defer_except() to release all non-holder entries, that were added by the other thread, because they must be deferred. This patch depends on "dm thin: replace dm_cell_release_singleton with cell_defer_except". Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: stable@vger.kernel.org
2012-12-21 20:23:31 +00:00
remap(tc, bio, result.block);
return DM_MAPIO_REMAPPED;
case -ENODATA:
case -EWOULDBLOCK:
thin_defer_cell(tc, virt_cell);
return DM_MAPIO_SUBMITTED;
default:
/*
* Must always call bio_io_error on failure.
* dm_thin_find_block can fail with -EINVAL if the
* pool is switched to fail-io mode.
*/
bio_io_error(bio);
cell_defer_no_holder(tc, virt_cell);
return DM_MAPIO_SUBMITTED;
}
}
static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
{
struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
struct request_queue *q;
if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
return 1;
q = bdev_get_queue(pt->data_dev->bdev);
return bdi_congested(q->backing_dev_info, bdi_bits);
}
static void requeue_bios(struct pool *pool)
{
unsigned long flags;
struct thin_c *tc;
rcu_read_lock();
list_for_each_entry_rcu(tc, &pool->active_thins, list) {
spin_lock_irqsave(&tc->lock, flags);
bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
bio_list_init(&tc->retry_on_resume_list);
spin_unlock_irqrestore(&tc->lock, flags);
}
rcu_read_unlock();
}
/*----------------------------------------------------------------
* Binding of control targets to a pool object
*--------------------------------------------------------------*/
static bool data_dev_supports_discard(struct pool_c *pt)
{
struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
return q && blk_queue_discard(q);
}
static bool is_factor(sector_t block_size, uint32_t n)
{
return !sector_div(block_size, n);
}
/*
* If discard_passdown was enabled verify that the data device
* supports discards. Disable discard_passdown if not.
*/
static void disable_passdown_if_not_supported(struct pool_c *pt)
{
struct pool *pool = pt->pool;
struct block_device *data_bdev = pt->data_dev->bdev;
struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
const char *reason = NULL;
char buf[BDEVNAME_SIZE];
if (!pt->adjusted_pf.discard_passdown)
return;
if (!data_dev_supports_discard(pt))
reason = "discard unsupported";
else if (data_limits->max_discard_sectors < pool->sectors_per_block)
reason = "max discard sectors smaller than a block";
if (reason) {
DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
pt->adjusted_pf.discard_passdown = false;
}
}
static int bind_control_target(struct pool *pool, struct dm_target *ti)
{
struct pool_c *pt = ti->private;
/*
* We want to make sure that a pool in PM_FAIL mode is never upgraded.
*/
enum pool_mode old_mode = get_pool_mode(pool);
enum pool_mode new_mode = pt->adjusted_pf.mode;
dm thin: fix set_pool_mode exposed pool operation races The pool mode must not be switched until after the corresponding pool process_* methods have been established. Otherwise, because set_pool_mode() isn't interlocked with the IO path for performance reasons, the IO path can end up executing process_* operations that don't match the mode. This patch eliminates problems like the following (as seen on really fast PCIe SSD storage when transitioning the pool's mode from PM_READ_ONLY to PM_WRITE): kernel: device-mapper: thin: 253:2: reached low water mark for data device: sending event. kernel: device-mapper: thin: 253:2: no free data space available. kernel: device-mapper: thin: 253:2: switching pool to read-only mode kernel: device-mapper: thin: 253:2: switching pool to write mode kernel: ------------[ cut here ]------------ kernel: WARNING: CPU: 11 PID: 7564 at drivers/md/dm-thin.c:995 handle_unserviceable_bio+0x146/0x160 [dm_thin_pool]() ... kernel: Workqueue: dm-thin do_worker [dm_thin_pool] kernel: 00000000000003e3 ffff880308831cc8 ffffffff8152ebcb 00000000000003e3 kernel: 0000000000000000 ffff880308831d08 ffffffff8104c46c ffff88032502a800 kernel: ffff880036409000 ffff88030ec7ce00 0000000000000001 00000000ffffffc3 kernel: Call Trace: kernel: [<ffffffff8152ebcb>] dump_stack+0x49/0x5e kernel: [<ffffffff8104c46c>] warn_slowpath_common+0x8c/0xc0 kernel: [<ffffffff8104c4ba>] warn_slowpath_null+0x1a/0x20 kernel: [<ffffffffa001e2c6>] handle_unserviceable_bio+0x146/0x160 [dm_thin_pool] kernel: [<ffffffffa001f276>] process_bio_read_only+0x136/0x180 [dm_thin_pool] kernel: [<ffffffffa0020b75>] process_deferred_bios+0xc5/0x230 [dm_thin_pool] kernel: [<ffffffffa0020d31>] do_worker+0x51/0x60 [dm_thin_pool] kernel: [<ffffffff81067823>] process_one_work+0x183/0x490 kernel: [<ffffffff81068c70>] worker_thread+0x120/0x3a0 kernel: [<ffffffff81068b50>] ? manage_workers+0x160/0x160 kernel: [<ffffffff8106e86e>] kthread+0xce/0xf0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: [<ffffffff8153b3ec>] ret_from_fork+0x7c/0xb0 kernel: [<ffffffff8106e7a0>] ? kthread_freezable_should_stop+0x70/0x70 kernel: ---[ end trace 3f00528e08ffa55c ]--- kernel: device-mapper: thin: pool mode is PM_WRITE not PM_READ_ONLY like expected!? dm-thin.c:995 was the WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY); at the top of handle_unserviceable_bio(). And as the additional debugging I had conveys: the pool mode was _not_ PM_READ_ONLY like expected, it was already PM_WRITE, yet pool->process_bio was still set to process_bio_read_only(). Also, while fixing this up, reduce logging of redundant pool mode transitions by checking new_mode is different from old_mode. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2013-12-20 19:27:28 +00:00
/*
* Don't change the pool's mode until set_pool_mode() below.
* Otherwise the pool's process_* function pointers may
* not match the desired pool mode.
*/
pt->adjusted_pf.mode = old_mode;
pool->ti = ti;
pool->pf = pt->adjusted_pf;
pool->low_water_blocks = pt->low_water_blocks;
set_pool_mode(pool, new_mode);
return 0;
}
static void unbind_control_target(struct pool *pool, struct dm_target *ti)
{
if (pool->ti == ti)
pool->ti = NULL;
}
/*----------------------------------------------------------------
* Pool creation
*--------------------------------------------------------------*/
/* Initialize pool features. */
static void pool_features_init(struct pool_features *pf)
{
pf->mode = PM_WRITE;
pf->zero_new_blocks = true;
pf->discard_enabled = true;
pf->discard_passdown = true;
pf->error_if_no_space = false;
}
static void __pool_destroy(struct pool *pool)
{
__pool_table_remove(pool);
vfree(pool->cell_sort_array);
if (dm_pool_metadata_close(pool->pmd) < 0)
DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
dm_bio_prison_destroy(pool->prison);
dm_kcopyd_client_destroy(pool->copier);
if (pool->wq)
destroy_workqueue(pool->wq);
if (pool->next_mapping)
mempool_free(pool->next_mapping, &pool->mapping_pool);
mempool_exit(&pool->mapping_pool);
dm_deferred_set_destroy(pool->shared_read_ds);
dm_deferred_set_destroy(pool->all_io_ds);
kfree(pool);
}
static struct kmem_cache *_new_mapping_cache;
static struct pool *pool_create(struct mapped_device *pool_md,
struct block_device *metadata_dev,
unsigned long block_size,
int read_only, char **error)
{
int r;
void *err_p;
struct pool *pool;
struct dm_pool_metadata *pmd;
bool format_device = read_only ? false : true;
pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
if (IS_ERR(pmd)) {
*error = "Error creating metadata object";
return (struct pool *)pmd;
}
pool = kzalloc(sizeof(*pool), GFP_KERNEL);
if (!pool) {
*error = "Error allocating memory for pool";
err_p = ERR_PTR(-ENOMEM);
goto bad_pool;
}
pool->pmd = pmd;
pool->sectors_per_block = block_size;
if (block_size & (block_size - 1))
pool->sectors_per_block_shift = -1;
else
pool->sectors_per_block_shift = __ffs(block_size);
pool->low_water_blocks = 0;
pool_features_init(&pool->pf);
pool->prison = dm_bio_prison_create();
if (!pool->prison) {
*error = "Error creating pool's bio prison";
err_p = ERR_PTR(-ENOMEM);
goto bad_prison;
}
pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
if (IS_ERR(pool->copier)) {
r = PTR_ERR(pool->copier);
*error = "Error creating pool's kcopyd client";
err_p = ERR_PTR(r);
goto bad_kcopyd_client;
}
/*
* Create singlethreaded workqueue that will service all devices
* that use this metadata.
*/
pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
if (!pool->wq) {
*error = "Error creating pool's workqueue";
err_p = ERR_PTR(-ENOMEM);
goto bad_wq;
}
throttle_init(&pool->throttle);
INIT_WORK(&pool->worker, do_worker);
INIT_DELAYED_WORK(&pool->waker, do_waker);
INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
spin_lock_init(&pool->lock);
bio_list_init(&pool->deferred_flush_bios);
INIT_LIST_HEAD(&pool->prepared_mappings);
INIT_LIST_HEAD(&pool->prepared_discards);
INIT_LIST_HEAD(&pool->prepared_discards_pt2);
INIT_LIST_HEAD(&pool->active_thins);
pool->low_water_triggered = false;
pool->suspended = true;
pool->out_of_data_space = false;
pool->shared_read_ds = dm_deferred_set_create();
if (!pool->shared_read_ds) {
*error = "Error creating pool's shared read deferred set";
err_p = ERR_PTR(-ENOMEM);
goto bad_shared_read_ds;
}
pool->all_io_ds = dm_deferred_set_create();
if (!pool->all_io_ds) {
*error = "Error creating pool's all io deferred set";
err_p = ERR_PTR(-ENOMEM);
goto bad_all_io_ds;
}
pool->next_mapping = NULL;
r = mempool_init_slab_pool(&pool->mapping_pool, MAPPING_POOL_SIZE,
_new_mapping_cache);
if (r) {
*error = "Error creating pool's mapping mempool";
err_p = ERR_PTR(r);
goto bad_mapping_pool;
}
pool->cell_sort_array = vmalloc(sizeof(*pool->cell_sort_array) * CELL_SORT_ARRAY_SIZE);
if (!pool->cell_sort_array) {
*error = "Error allocating cell sort array";
err_p = ERR_PTR(-ENOMEM);
goto bad_sort_array;
}
pool->ref_count = 1;
pool->last_commit_jiffies = jiffies;
pool->pool_md = pool_md;
pool->md_dev = metadata_dev;
__pool_table_insert(pool);
return pool;
bad_sort_array:
mempool_exit(&pool->mapping_pool);
bad_mapping_pool:
dm_deferred_set_destroy(pool->all_io_ds);
bad_all_io_ds:
dm_deferred_set_destroy(pool->shared_read_ds);
bad_shared_read_ds:
destroy_workqueue(pool->wq);
bad_wq:
dm_kcopyd_client_destroy(pool->copier);
bad_kcopyd_client:
dm_bio_prison_destroy(pool->prison);
bad_prison:
kfree(pool);
bad_pool:
if (dm_pool_metadata_close(pmd))
DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
return err_p;
}
static void __pool_inc(struct pool *pool)
{
BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
pool->ref_count++;
}
static void __pool_dec(struct pool *pool)
{
BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
BUG_ON(!pool->ref_count);
if (!--pool->ref_count)
__pool_destroy(pool);
}
static struct pool *__pool_find(struct mapped_device *pool_md,
struct block_device *metadata_dev,
unsigned long block_size, int read_only,
char **error, int *created)
{
struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
if (pool) {
if (pool->pool_md != pool_md) {
*error = "metadata device already in use by a pool";
return ERR_PTR(-EBUSY);
}
__pool_inc(pool);
} else {
pool = __pool_table_lookup(pool_md);
if (pool) {
if (pool->md_dev != metadata_dev) {
*error = "different pool cannot replace a pool";
return ERR_PTR(-EINVAL);
}
__pool_inc(pool);
} else {
pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
*created = 1;
}
}
return pool;
}
/*----------------------------------------------------------------
* Pool target methods
*--------------------------------------------------------------*/
static void pool_dtr(struct dm_target *ti)
{
struct pool_c *pt = ti->private;
mutex_lock(&dm_thin_pool_table.mutex);
unbind_control_target(pt->pool, ti);
__pool_dec(pt->pool);
dm_put_device(ti, pt->metadata_dev);
dm_put_device(ti, pt->data_dev);
kfree(pt);
mutex_unlock(&dm_thin_pool_table.mutex);
}
static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
struct dm_target *ti)
{
int r;
unsigned argc;
const char *arg_name;
static const struct dm_arg _args[] = {
{0, 4, "Invalid number of pool feature arguments"},
};
/*
* No feature arguments supplied.
*/
if (!as->argc)
return 0;
r = dm_read_arg_group(_args, as, &argc, &ti->error);
if (r)
return -EINVAL;
while (argc && !r) {
arg_name = dm_shift_arg(as);
argc--;
if (!strcasecmp(arg_name, "skip_block_zeroing"))
pf->zero_new_blocks = false;
else if (!strcasecmp(arg_name, "ignore_discard"))
pf->discard_enabled = false;
else if (!strcasecmp(arg_name, "no_discard_passdown"))
pf->discard_passdown = false;
else if (!strcasecmp(arg_name, "read_only"))
pf->mode = PM_READ_ONLY;
else if (!strcasecmp(arg_name, "error_if_no_space"))
pf->error_if_no_space = true;
else {
ti->error = "Unrecognised pool feature requested";
r = -EINVAL;
break;
}
}
return r;
}
static void metadata_low_callback(void *context)
{
struct pool *pool = context;
DMWARN("%s: reached low water mark for metadata device: sending event.",
dm_device_name(pool->pool_md));
dm_table_event(pool->ti->table);
}
dm thin: allow metadata space larger than supported to go unused It was always intended that a user could provide a thin metadata device that is larger than the max supported by the on-disk format. The extra space would just go unused. Unfortunately that never worked. If the user attempted to use a larger metadata device on creation they would get an error like the following: device-mapper: space map common: space map too large device-mapper: transaction manager: couldn't create metadata space map device-mapper: thin metadata: tm_create_with_sm failed device-mapper: table: 252:17: thin-pool: Error creating metadata object device-mapper: ioctl: error adding target to table Fix this by allowing the initial metadata space map creation to cap its size at the max number of blocks supported (DM_SM_METADATA_MAX_BLOCKS). get_metadata_dev_size() must also impose DM_SM_METADATA_MAX_BLOCKS (via THIN_METADATA_MAX_SECTORS), otherwise extending metadata would cap at THIN_METADATA_MAX_SECTORS_WARNING (which is larger than supported). Also, the calculation for THIN_METADATA_MAX_SECTORS didn't account for the sizeof the disk_bitmap_header. So the supported maximum metadata size is a bit smaller (reduced from 33423360 to 33292800 sectors). Lastly, remove the "excess space will not be used" warning message from get_metadata_dev_size(); it resulted in printing the warning multiple times. Factor out warn_if_metadata_device_too_big(), call it from pool_ctr() and maybe_resize_metadata_dev(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-02-13 04:58:15 +00:00
static sector_t get_dev_size(struct block_device *bdev)
{
return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
}
static void warn_if_metadata_device_too_big(struct block_device *bdev)
{
dm thin: allow metadata space larger than supported to go unused It was always intended that a user could provide a thin metadata device that is larger than the max supported by the on-disk format. The extra space would just go unused. Unfortunately that never worked. If the user attempted to use a larger metadata device on creation they would get an error like the following: device-mapper: space map common: space map too large device-mapper: transaction manager: couldn't create metadata space map device-mapper: thin metadata: tm_create_with_sm failed device-mapper: table: 252:17: thin-pool: Error creating metadata object device-mapper: ioctl: error adding target to table Fix this by allowing the initial metadata space map creation to cap its size at the max number of blocks supported (DM_SM_METADATA_MAX_BLOCKS). get_metadata_dev_size() must also impose DM_SM_METADATA_MAX_BLOCKS (via THIN_METADATA_MAX_SECTORS), otherwise extending metadata would cap at THIN_METADATA_MAX_SECTORS_WARNING (which is larger than supported). Also, the calculation for THIN_METADATA_MAX_SECTORS didn't account for the sizeof the disk_bitmap_header. So the supported maximum metadata size is a bit smaller (reduced from 33423360 to 33292800 sectors). Lastly, remove the "excess space will not be used" warning message from get_metadata_dev_size(); it resulted in printing the warning multiple times. Factor out warn_if_metadata_device_too_big(), call it from pool_ctr() and maybe_resize_metadata_dev(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-02-13 04:58:15 +00:00
sector_t metadata_dev_size = get_dev_size(bdev);
char buffer[BDEVNAME_SIZE];
dm thin: allow metadata space larger than supported to go unused It was always intended that a user could provide a thin metadata device that is larger than the max supported by the on-disk format. The extra space would just go unused. Unfortunately that never worked. If the user attempted to use a larger metadata device on creation they would get an error like the following: device-mapper: space map common: space map too large device-mapper: transaction manager: couldn't create metadata space map device-mapper: thin metadata: tm_create_with_sm failed device-mapper: table: 252:17: thin-pool: Error creating metadata object device-mapper: ioctl: error adding target to table Fix this by allowing the initial metadata space map creation to cap its size at the max number of blocks supported (DM_SM_METADATA_MAX_BLOCKS). get_metadata_dev_size() must also impose DM_SM_METADATA_MAX_BLOCKS (via THIN_METADATA_MAX_SECTORS), otherwise extending metadata would cap at THIN_METADATA_MAX_SECTORS_WARNING (which is larger than supported). Also, the calculation for THIN_METADATA_MAX_SECTORS didn't account for the sizeof the disk_bitmap_header. So the supported maximum metadata size is a bit smaller (reduced from 33423360 to 33292800 sectors). Lastly, remove the "excess space will not be used" warning message from get_metadata_dev_size(); it resulted in printing the warning multiple times. Factor out warn_if_metadata_device_too_big(), call it from pool_ctr() and maybe_resize_metadata_dev(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-02-13 04:58:15 +00:00
if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
dm thin: allow metadata space larger than supported to go unused It was always intended that a user could provide a thin metadata device that is larger than the max supported by the on-disk format. The extra space would just go unused. Unfortunately that never worked. If the user attempted to use a larger metadata device on creation they would get an error like the following: device-mapper: space map common: space map too large device-mapper: transaction manager: couldn't create metadata space map device-mapper: thin metadata: tm_create_with_sm failed device-mapper: table: 252:17: thin-pool: Error creating metadata object device-mapper: ioctl: error adding target to table Fix this by allowing the initial metadata space map creation to cap its size at the max number of blocks supported (DM_SM_METADATA_MAX_BLOCKS). get_metadata_dev_size() must also impose DM_SM_METADATA_MAX_BLOCKS (via THIN_METADATA_MAX_SECTORS), otherwise extending metadata would cap at THIN_METADATA_MAX_SECTORS_WARNING (which is larger than supported). Also, the calculation for THIN_METADATA_MAX_SECTORS didn't account for the sizeof the disk_bitmap_header. So the supported maximum metadata size is a bit smaller (reduced from 33423360 to 33292800 sectors). Lastly, remove the "excess space will not be used" warning message from get_metadata_dev_size(); it resulted in printing the warning multiple times. Factor out warn_if_metadata_device_too_big(), call it from pool_ctr() and maybe_resize_metadata_dev(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-02-13 04:58:15 +00:00
}
static sector_t get_metadata_dev_size(struct block_device *bdev)
{
sector_t metadata_dev_size = get_dev_size(bdev);
if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
metadata_dev_size = THIN_METADATA_MAX_SECTORS;
return metadata_dev_size;
}
static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
{
sector_t metadata_dev_size = get_metadata_dev_size(bdev);
dm thin: allow metadata space larger than supported to go unused It was always intended that a user could provide a thin metadata device that is larger than the max supported by the on-disk format. The extra space would just go unused. Unfortunately that never worked. If the user attempted to use a larger metadata device on creation they would get an error like the following: device-mapper: space map common: space map too large device-mapper: transaction manager: couldn't create metadata space map device-mapper: thin metadata: tm_create_with_sm failed device-mapper: table: 252:17: thin-pool: Error creating metadata object device-mapper: ioctl: error adding target to table Fix this by allowing the initial metadata space map creation to cap its size at the max number of blocks supported (DM_SM_METADATA_MAX_BLOCKS). get_metadata_dev_size() must also impose DM_SM_METADATA_MAX_BLOCKS (via THIN_METADATA_MAX_SECTORS), otherwise extending metadata would cap at THIN_METADATA_MAX_SECTORS_WARNING (which is larger than supported). Also, the calculation for THIN_METADATA_MAX_SECTORS didn't account for the sizeof the disk_bitmap_header. So the supported maximum metadata size is a bit smaller (reduced from 33423360 to 33292800 sectors). Lastly, remove the "excess space will not be used" warning message from get_metadata_dev_size(); it resulted in printing the warning multiple times. Factor out warn_if_metadata_device_too_big(), call it from pool_ctr() and maybe_resize_metadata_dev(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-02-13 04:58:15 +00:00
sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
return metadata_dev_size;
}
/*
* When a metadata threshold is crossed a dm event is triggered, and
* userland should respond by growing the metadata device. We could let
* userland set the threshold, like we do with the data threshold, but I'm
* not sure they know enough to do this well.
*/
static dm_block_t calc_metadata_threshold(struct pool_c *pt)
{
/*
* 4M is ample for all ops with the possible exception of thin
* device deletion which is harmless if it fails (just retry the
* delete after you've grown the device).
*/
dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
return min((dm_block_t)1024ULL /* 4M */, quarter);
}
/*
* thin-pool <metadata dev> <data dev>
* <data block size (sectors)>
* <low water mark (blocks)>
* [<#feature args> [<arg>]*]
*
* Optional feature arguments are:
* skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
* ignore_discard: disable discard
* no_discard_passdown: don't pass discards down to the data device
* read_only: Don't allow any changes to be made to the pool metadata.
* error_if_no_space: error IOs, instead of queueing, if no space.
*/
static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
int r, pool_created = 0;
struct pool_c *pt;
struct pool *pool;
struct pool_features pf;
struct dm_arg_set as;
struct dm_dev *data_dev;
unsigned long block_size;
dm_block_t low_water_blocks;
struct dm_dev *metadata_dev;
fmode_t metadata_mode;
/*
* FIXME Remove validation from scope of lock.
*/
mutex_lock(&dm_thin_pool_table.mutex);
if (argc < 4) {
ti->error = "Invalid argument count";
r = -EINVAL;
goto out_unlock;
}
as.argc = argc;
as.argv = argv;
/*
* Set default pool features.
*/
pool_features_init(&pf);
dm_consume_args(&as, 4);
r = parse_pool_features(&as, &pf, ti);
if (r)
goto out_unlock;
metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
if (r) {
ti->error = "Error opening metadata block device";
goto out_unlock;
}
dm thin: allow metadata space larger than supported to go unused It was always intended that a user could provide a thin metadata device that is larger than the max supported by the on-disk format. The extra space would just go unused. Unfortunately that never worked. If the user attempted to use a larger metadata device on creation they would get an error like the following: device-mapper: space map common: space map too large device-mapper: transaction manager: couldn't create metadata space map device-mapper: thin metadata: tm_create_with_sm failed device-mapper: table: 252:17: thin-pool: Error creating metadata object device-mapper: ioctl: error adding target to table Fix this by allowing the initial metadata space map creation to cap its size at the max number of blocks supported (DM_SM_METADATA_MAX_BLOCKS). get_metadata_dev_size() must also impose DM_SM_METADATA_MAX_BLOCKS (via THIN_METADATA_MAX_SECTORS), otherwise extending metadata would cap at THIN_METADATA_MAX_SECTORS_WARNING (which is larger than supported). Also, the calculation for THIN_METADATA_MAX_SECTORS didn't account for the sizeof the disk_bitmap_header. So the supported maximum metadata size is a bit smaller (reduced from 33423360 to 33292800 sectors). Lastly, remove the "excess space will not be used" warning message from get_metadata_dev_size(); it resulted in printing the warning multiple times. Factor out warn_if_metadata_device_too_big(), call it from pool_ctr() and maybe_resize_metadata_dev(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-02-13 04:58:15 +00:00
warn_if_metadata_device_too_big(metadata_dev->bdev);
r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
if (r) {
ti->error = "Error getting data device";
goto out_metadata;
}
if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
ti->error = "Invalid block size";
r = -EINVAL;
goto out;
}
if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
ti->error = "Invalid low water mark";
r = -EINVAL;
goto out;
}
pt = kzalloc(sizeof(*pt), GFP_KERNEL);
if (!pt) {
r = -ENOMEM;
goto out;
}
pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
if (IS_ERR(pool)) {
r = PTR_ERR(pool);
goto out_free_pt;
}
/*
* 'pool_created' reflects whether this is the first table load.
* Top level discard support is not allowed to be changed after
* initial load. This would require a pool reload to trigger thin
* device changes.
*/
if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
ti->error = "Discard support cannot be disabled once enabled";
r = -EINVAL;
goto out_flags_changed;
}
pt->pool = pool;
pt->ti = ti;
pt->metadata_dev = metadata_dev;
pt->data_dev = data_dev;
pt->low_water_blocks = low_water_blocks;
pt->adjusted_pf = pt->requested_pf = pf;
ti->num_flush_bios = 1;
/*
* Only need to enable discards if the pool should pass
* them down to the data device. The thin device's discard
* processing will cause mappings to be removed from the btree.
*/
if (pf.discard_enabled && pf.discard_passdown) {
ti->num_discard_bios = 1;
/*
* Setting 'discards_supported' circumvents the normal
* stacking of discard limits (this keeps the pool and
* thin devices' discard limits consistent).
*/
ti->discards_supported = true;
}
ti->private = pt;
r = dm_pool_register_metadata_threshold(pt->pool->pmd,
calc_metadata_threshold(pt),
metadata_low_callback,
pool);
if (r)
goto out_flags_changed;
pt->callbacks.congested_fn = pool_is_congested;
dm_table_add_target_callbacks(ti->table, &pt->callbacks);
mutex_unlock(&dm_thin_pool_table.mutex);
return 0;
out_flags_changed:
__pool_dec(pool);
out_free_pt:
kfree(pt);
out:
dm_put_device(ti, data_dev);
out_metadata:
dm_put_device(ti, metadata_dev);
out_unlock:
mutex_unlock(&dm_thin_pool_table.mutex);
return r;
}
static int pool_map(struct dm_target *ti, struct bio *bio)
{
int r;
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
unsigned long flags;
/*
* As this is a singleton target, ti->begin is always zero.
*/
spin_lock_irqsave(&pool->lock, flags);
bio_set_dev(bio, pt->data_dev->bdev);
r = DM_MAPIO_REMAPPED;
spin_unlock_irqrestore(&pool->lock, flags);
return r;
}
static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
{
int r;
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
sector_t data_size = ti->len;
dm_block_t sb_data_size;
*need_commit = false;
(void) sector_div(data_size, pool->sectors_per_block);
r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
if (r) {
DMERR("%s: failed to retrieve data device size",
dm_device_name(pool->pool_md));
return r;
}
if (data_size < sb_data_size) {
DMERR("%s: pool target (%llu blocks) too small: expected %llu",
dm_device_name(pool->pool_md),
(unsigned long long)data_size, sb_data_size);
return -EINVAL;
} else if (data_size > sb_data_size) {
if (dm_pool_metadata_needs_check(pool->pmd)) {
DMERR("%s: unable to grow the data device until repaired.",
dm_device_name(pool->pool_md));
return 0;
}
if (sb_data_size)
DMINFO("%s: growing the data device from %llu to %llu blocks",
dm_device_name(pool->pool_md),
sb_data_size, (unsigned long long)data_size);
r = dm_pool_resize_data_dev(pool->pmd, data_size);
if (r) {
metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
return r;
}
*need_commit = true;
}
return 0;
}
static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
{
int r;
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
dm_block_t metadata_dev_size, sb_metadata_dev_size;
*need_commit = false;
metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
if (r) {
DMERR("%s: failed to retrieve metadata device size",
dm_device_name(pool->pool_md));
return r;
}
if (metadata_dev_size < sb_metadata_dev_size) {
DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
dm_device_name(pool->pool_md),
metadata_dev_size, sb_metadata_dev_size);
return -EINVAL;
} else if (metadata_dev_size > sb_metadata_dev_size) {
if (dm_pool_metadata_needs_check(pool->pmd)) {
DMERR("%s: unable to grow the metadata device until repaired.",
dm_device_name(pool->pool_md));
return 0;
}
dm thin: allow metadata space larger than supported to go unused It was always intended that a user could provide a thin metadata device that is larger than the max supported by the on-disk format. The extra space would just go unused. Unfortunately that never worked. If the user attempted to use a larger metadata device on creation they would get an error like the following: device-mapper: space map common: space map too large device-mapper: transaction manager: couldn't create metadata space map device-mapper: thin metadata: tm_create_with_sm failed device-mapper: table: 252:17: thin-pool: Error creating metadata object device-mapper: ioctl: error adding target to table Fix this by allowing the initial metadata space map creation to cap its size at the max number of blocks supported (DM_SM_METADATA_MAX_BLOCKS). get_metadata_dev_size() must also impose DM_SM_METADATA_MAX_BLOCKS (via THIN_METADATA_MAX_SECTORS), otherwise extending metadata would cap at THIN_METADATA_MAX_SECTORS_WARNING (which is larger than supported). Also, the calculation for THIN_METADATA_MAX_SECTORS didn't account for the sizeof the disk_bitmap_header. So the supported maximum metadata size is a bit smaller (reduced from 33423360 to 33292800 sectors). Lastly, remove the "excess space will not be used" warning message from get_metadata_dev_size(); it resulted in printing the warning multiple times. Factor out warn_if_metadata_device_too_big(), call it from pool_ctr() and maybe_resize_metadata_dev(). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-02-13 04:58:15 +00:00
warn_if_metadata_device_too_big(pool->md_dev);
DMINFO("%s: growing the metadata device from %llu to %llu blocks",
dm_device_name(pool->pool_md),
sb_metadata_dev_size, metadata_dev_size);
r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
if (r) {
metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
return r;
}
*need_commit = true;
}
return 0;
}
/*
* Retrieves the number of blocks of the data device from
* the superblock and compares it to the actual device size,
* thus resizing the data device in case it has grown.
*
* This both copes with opening preallocated data devices in the ctr
* being followed by a resume
* -and-
* calling the resume method individually after userspace has
* grown the data device in reaction to a table event.
*/
static int pool_preresume(struct dm_target *ti)
{
int r;
bool need_commit1, need_commit2;
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
/*
* Take control of the pool object.
*/
r = bind_control_target(pool, ti);
if (r)
return r;
r = maybe_resize_data_dev(ti, &need_commit1);
if (r)
return r;
r = maybe_resize_metadata_dev(ti, &need_commit2);
if (r)
return r;
if (need_commit1 || need_commit2)
(void) commit(pool);
return 0;
}
static void pool_suspend_active_thins(struct pool *pool)
{
struct thin_c *tc;
/* Suspend all active thin devices */
tc = get_first_thin(pool);
while (tc) {
dm_internal_suspend_noflush(tc->thin_md);
tc = get_next_thin(pool, tc);
}
}
static void pool_resume_active_thins(struct pool *pool)
{
struct thin_c *tc;
/* Resume all active thin devices */
tc = get_first_thin(pool);
while (tc) {
dm_internal_resume(tc->thin_md);
tc = get_next_thin(pool, tc);
}
}
static void pool_resume(struct dm_target *ti)
{
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
unsigned long flags;
/*
* Must requeue active_thins' bios and then resume
* active_thins _before_ clearing 'suspend' flag.
*/
requeue_bios(pool);
pool_resume_active_thins(pool);
spin_lock_irqsave(&pool->lock, flags);
pool->low_water_triggered = false;
pool->suspended = false;
spin_unlock_irqrestore(&pool->lock, flags);
do_waker(&pool->waker.work);
}
static void pool_presuspend(struct dm_target *ti)
{
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
unsigned long flags;
spin_lock_irqsave(&pool->lock, flags);
pool->suspended = true;
spin_unlock_irqrestore(&pool->lock, flags);
pool_suspend_active_thins(pool);
}
static void pool_presuspend_undo(struct dm_target *ti)
{
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
unsigned long flags;
pool_resume_active_thins(pool);
spin_lock_irqsave(&pool->lock, flags);
pool->suspended = false;
spin_unlock_irqrestore(&pool->lock, flags);
}
static void pool_postsuspend(struct dm_target *ti)
{
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
cancel_delayed_work_sync(&pool->waker);
cancel_delayed_work_sync(&pool->no_space_timeout);
flush_workqueue(pool->wq);
(void) commit(pool);
}
static int check_arg_count(unsigned argc, unsigned args_required)
{
if (argc != args_required) {
DMWARN("Message received with %u arguments instead of %u.",
argc, args_required);
return -EINVAL;
}
return 0;
}
static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
{
if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
*dev_id <= MAX_DEV_ID)
return 0;
if (warning)
DMWARN("Message received with invalid device id: %s", arg);
return -EINVAL;
}
static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
{
dm_thin_id dev_id;
int r;
r = check_arg_count(argc, 2);
if (r)
return r;
r = read_dev_id(argv[1], &dev_id, 1);
if (r)
return r;
r = dm_pool_create_thin(pool->pmd, dev_id);
if (r) {
DMWARN("Creation of new thinly-provisioned device with id %s failed.",
argv[1]);
return r;
}
return 0;
}
static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
{
dm_thin_id dev_id;
dm_thin_id origin_dev_id;
int r;
r = check_arg_count(argc, 3);
if (r)
return r;
r = read_dev_id(argv[1], &dev_id, 1);
if (r)
return r;
r = read_dev_id(argv[2], &origin_dev_id, 1);
if (r)
return r;
r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
if (r) {
DMWARN("Creation of new snapshot %s of device %s failed.",
argv[1], argv[2]);
return r;
}
return 0;
}
static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
{
dm_thin_id dev_id;
int r;
r = check_arg_count(argc, 2);
if (r)
return r;
r = read_dev_id(argv[1], &dev_id, 1);
if (r)
return r;
r = dm_pool_delete_thin_device(pool->pmd, dev_id);
if (r)
DMWARN("Deletion of thin device %s failed.", argv[1]);
return r;
}
static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
{
dm_thin_id old_id, new_id;
int r;
r = check_arg_count(argc, 3);
if (r)
return r;
if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
return -EINVAL;
}
if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
return -EINVAL;
}
r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
if (r) {
DMWARN("Failed to change transaction id from %s to %s.",
argv[1], argv[2]);
return r;
}
return 0;
}
static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
{
int r;
r = check_arg_count(argc, 1);
if (r)
return r;
(void) commit(pool);
r = dm_pool_reserve_metadata_snap(pool->pmd);
if (r)
DMWARN("reserve_metadata_snap message failed.");
return r;
}
static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
{
int r;
r = check_arg_count(argc, 1);
if (r)
return r;
r = dm_pool_release_metadata_snap(pool->pmd);
if (r)
DMWARN("release_metadata_snap message failed.");
return r;
}
/*
* Messages supported:
* create_thin <dev_id>
* create_snap <dev_id> <origin_id>
* delete <dev_id>
* set_transaction_id <current_trans_id> <new_trans_id>
* reserve_metadata_snap
* release_metadata_snap
*/
static int pool_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
int r = -EINVAL;
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
if (get_pool_mode(pool) >= PM_READ_ONLY) {
DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
dm_device_name(pool->pool_md));
return -EOPNOTSUPP;
}
if (!strcasecmp(argv[0], "create_thin"))
r = process_create_thin_mesg(argc, argv, pool);
else if (!strcasecmp(argv[0], "create_snap"))
r = process_create_snap_mesg(argc, argv, pool);
else if (!strcasecmp(argv[0], "delete"))
r = process_delete_mesg(argc, argv, pool);
else if (!strcasecmp(argv[0], "set_transaction_id"))
r = process_set_transaction_id_mesg(argc, argv, pool);
else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
r = process_reserve_metadata_snap_mesg(argc, argv, pool);
else if (!strcasecmp(argv[0], "release_metadata_snap"))
r = process_release_metadata_snap_mesg(argc, argv, pool);
else
DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
if (!r)
(void) commit(pool);
return r;
}
static void emit_flags(struct pool_features *pf, char *result,
unsigned sz, unsigned maxlen)
{
unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
!pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
pf->error_if_no_space;
DMEMIT("%u ", count);
if (!pf->zero_new_blocks)
DMEMIT("skip_block_zeroing ");
if (!pf->discard_enabled)
DMEMIT("ignore_discard ");
if (!pf->discard_passdown)
DMEMIT("no_discard_passdown ");
if (pf->mode == PM_READ_ONLY)
DMEMIT("read_only ");
if (pf->error_if_no_space)
DMEMIT("error_if_no_space ");
}
/*
* Status line is:
* <transaction id> <used metadata sectors>/<total metadata sectors>
* <used data sectors>/<total data sectors> <held metadata root>
* <pool mode> <discard config> <no space config> <needs_check>
*/
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
static void pool_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
int r;
unsigned sz = 0;
uint64_t transaction_id;
dm_block_t nr_free_blocks_data;
dm_block_t nr_free_blocks_metadata;
dm_block_t nr_blocks_data;
dm_block_t nr_blocks_metadata;
dm_block_t held_root;
char buf[BDEVNAME_SIZE];
char buf2[BDEVNAME_SIZE];
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
switch (type) {
case STATUSTYPE_INFO:
if (get_pool_mode(pool) == PM_FAIL) {
DMEMIT("Fail");
break;
}
/* Commit to ensure statistics aren't out-of-date */
if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
(void) commit(pool);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
if (r) {
DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
dm_device_name(pool->pool_md), r);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
goto err;
}
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
if (r) {
DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
dm_device_name(pool->pool_md), r);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
goto err;
}
r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
if (r) {
DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
dm_device_name(pool->pool_md), r);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
goto err;
}
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
if (r) {
DMERR("%s: dm_pool_get_free_block_count returned %d",
dm_device_name(pool->pool_md), r);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
goto err;
}
r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
if (r) {
DMERR("%s: dm_pool_get_data_dev_size returned %d",
dm_device_name(pool->pool_md), r);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
goto err;
}
r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
if (r) {
DMERR("%s: dm_pool_get_metadata_snap returned %d",
dm_device_name(pool->pool_md), r);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
goto err;
}
DMEMIT("%llu %llu/%llu %llu/%llu ",
(unsigned long long)transaction_id,
(unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
(unsigned long long)nr_blocks_metadata,
(unsigned long long)(nr_blocks_data - nr_free_blocks_data),
(unsigned long long)nr_blocks_data);
if (held_root)
DMEMIT("%llu ", held_root);
else
DMEMIT("- ");
if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
DMEMIT("out_of_data_space ");
else if (pool->pf.mode == PM_READ_ONLY)
DMEMIT("ro ");
else
DMEMIT("rw ");
if (!pool->pf.discard_enabled)
DMEMIT("ignore_discard ");
else if (pool->pf.discard_passdown)
DMEMIT("discard_passdown ");
else
DMEMIT("no_discard_passdown ");
if (pool->pf.error_if_no_space)
DMEMIT("error_if_no_space ");
else
DMEMIT("queue_if_no_space ");
if (dm_pool_metadata_needs_check(pool->pmd))
DMEMIT("needs_check ");
else
DMEMIT("- ");
break;
case STATUSTYPE_TABLE:
DMEMIT("%s %s %lu %llu ",
format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
(unsigned long)pool->sectors_per_block,
(unsigned long long)pt->low_water_blocks);
emit_flags(&pt->requested_pf, result, sz, maxlen);
break;
}
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
return;
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
err:
DMEMIT("Error");
}
static int pool_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
struct pool_c *pt = ti->private;
return fn(ti, pt->data_dev, 0, ti->len, data);
}
static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct pool_c *pt = ti->private;
struct pool *pool = pt->pool;
sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
/*
* If max_sectors is smaller than pool->sectors_per_block adjust it
* to the highest possible power-of-2 factor of pool->sectors_per_block.
* This is especially beneficial when the pool's data device is a RAID
* device that has a full stripe width that matches pool->sectors_per_block
* -- because even though partial RAID stripe-sized IOs will be issued to a
* single RAID stripe; when aggregated they will end on a full RAID stripe
* boundary.. which avoids additional partial RAID stripe writes cascading
*/
if (limits->max_sectors < pool->sectors_per_block) {
while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
limits->max_sectors--;
limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
}
}
/*
* If the system-determined stacked limits are compatible with the
* pool's blocksize (io_opt is a factor) do not override them.
*/
if (io_opt_sectors < pool->sectors_per_block ||
!is_factor(io_opt_sectors, pool->sectors_per_block)) {
if (is_factor(pool->sectors_per_block, limits->max_sectors))
blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
else
blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
}
/*
* pt->adjusted_pf is a staging area for the actual features to use.
* They get transferred to the live pool in bind_control_target()
* called from pool_preresume().
*/
if (!pt->adjusted_pf.discard_enabled) {
/*
* Must explicitly disallow stacking discard limits otherwise the
* block layer will stack them if pool's data device has support.
* QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
* user to see that, so make sure to set all discard limits to 0.
*/
limits->discard_granularity = 0;
return;
}
disable_passdown_if_not_supported(pt);
/*
* The pool uses the same discard limits as the underlying data
* device. DM core has already set this up.
*/
}
static struct target_type pool_target = {
.name = "thin-pool",
.features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
DM_TARGET_IMMUTABLE,
.version = {1, 19, 0},
.module = THIS_MODULE,
.ctr = pool_ctr,
.dtr = pool_dtr,
.map = pool_map,
.presuspend = pool_presuspend,
.presuspend_undo = pool_presuspend_undo,
.postsuspend = pool_postsuspend,
.preresume = pool_preresume,
.resume = pool_resume,
.message = pool_message,
.status = pool_status,
.iterate_devices = pool_iterate_devices,
.io_hints = pool_io_hints,
};
/*----------------------------------------------------------------
* Thin target methods
*--------------------------------------------------------------*/
dm thin: fix rcu_read_lock being held in code that can sleep Commit c140e1c4e23 ("dm thin: use per thin device deferred bio lists") introduced the use of an rculist for all active thin devices. The use of rcu_read_lock() in process_deferred_bios() can result in a BUG if a dm_bio_prison_cell must be allocated as a side-effect of bio_detain(): BUG: sleeping function called from invalid context at mm/mempool.c:203 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u8:0 3 locks held by kworker/u8:0/6: #0: ("dm-" "thin"){.+.+..}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #1: ((&pool->worker)){+.+...}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550 #2: (rcu_read_lock){.+.+..}, at: [<ffffffff816360b5>] do_worker+0x5/0x4d0 We can't process deferred bios with the rcu lock held, since dm_bio_prison_cell allocation may block if the bio-prison's cell mempool is exhausted. To fix: - Introduce a refcount and completion field to each thin_c - Add thin_get/put methods for adjusting the refcount. If the refcount hits zero then the completion is triggered. - Initialise refcount to 1 when creating thin_c - When iterating the active_thins list we thin_get() whilst the rcu lock is held. - After the rcu lock is dropped we process the deferred bios for that thin. - When destroying a thin_c we thin_put() and then wait for the completion -- to avoid a race between the worker thread iterating from that thin_c and destroying the thin_c. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-04-08 10:29:01 +00:00
static void thin_get(struct thin_c *tc)
{
atomic_inc(&tc->refcount);
}
static void thin_put(struct thin_c *tc)
{
if (atomic_dec_and_test(&tc->refcount))
complete(&tc->can_destroy);
}
static void thin_dtr(struct dm_target *ti)
{
struct thin_c *tc = ti->private;
unsigned long flags;
spin_lock_irqsave(&tc->pool->lock, flags);
list_del_rcu(&tc->list);
spin_unlock_irqrestore(&tc->pool->lock, flags);
synchronize_rcu();
thin_put(tc);
wait_for_completion(&tc->can_destroy);
mutex_lock(&dm_thin_pool_table.mutex);
__pool_dec(tc->pool);
dm_pool_close_thin_device(tc->td);
dm_put_device(ti, tc->pool_dev);
if (tc->origin_dev)
dm_put_device(ti, tc->origin_dev);
kfree(tc);
mutex_unlock(&dm_thin_pool_table.mutex);
}
/*
* Thin target parameters:
*
* <pool_dev> <dev_id> [origin_dev]
*
* pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
* dev_id: the internal device identifier
* origin_dev: a device external to the pool that should act as the origin
*
* If the pool device has discards disabled, they get disabled for the thin
* device as well.
*/
static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
int r;
struct thin_c *tc;
struct dm_dev *pool_dev, *origin_dev;
struct mapped_device *pool_md;
unsigned long flags;
mutex_lock(&dm_thin_pool_table.mutex);
if (argc != 2 && argc != 3) {
ti->error = "Invalid argument count";
r = -EINVAL;
goto out_unlock;
}
tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
if (!tc) {
ti->error = "Out of memory";
r = -ENOMEM;
goto out_unlock;
}
tc->thin_md = dm_table_get_md(ti->table);
spin_lock_init(&tc->lock);
INIT_LIST_HEAD(&tc->deferred_cells);
bio_list_init(&tc->deferred_bio_list);
bio_list_init(&tc->retry_on_resume_list);
tc->sort_bio_list = RB_ROOT;
if (argc == 3) {
r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
if (r) {
ti->error = "Error opening origin device";
goto bad_origin_dev;
}
tc->origin_dev = origin_dev;
}
r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
if (r) {
ti->error = "Error opening pool device";
goto bad_pool_dev;
}
tc->pool_dev = pool_dev;
if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
ti->error = "Invalid device id";
r = -EINVAL;
goto bad_common;
}
pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
if (!pool_md) {
ti->error = "Couldn't get pool mapped device";
r = -EINVAL;
goto bad_common;
}
tc->pool = __pool_table_lookup(pool_md);
if (!tc->pool) {
ti->error = "Couldn't find pool object";
r = -EINVAL;
goto bad_pool_lookup;
}
__pool_inc(tc->pool);
if (get_pool_mode(tc->pool) == PM_FAIL) {
ti->error = "Couldn't open thin device, Pool is in fail mode";
r = -EINVAL;
goto bad_pool;
}
r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
if (r) {
ti->error = "Couldn't open thin internal device";
goto bad_pool;
}
r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
if (r)
goto bad;
ti->num_flush_bios = 1;
ti->flush_supported = true;
ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
/* In case the pool supports discards, pass them on. */
if (tc->pool->pf.discard_enabled) {
ti->discards_supported = true;
ti->num_discard_bios = 1;
ti->split_discard_bios = false;
}
mutex_unlock(&dm_thin_pool_table.mutex);
spin_lock_irqsave(&tc->pool->lock, flags);
if (tc->pool->suspended) {
spin_unlock_irqrestore(&tc->pool->lock, flags);
mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
ti->error = "Unable to activate thin device while pool is suspended";
r = -EINVAL;
goto bad;
}
dm thin: fix crash by initializing thin device's refcount and completion earlier Commit 80e96c5484be ("dm thin: do not allow thin device activation while pool is suspended") delayed the initialization of a new thin device's refcount and completion until after this new thin was added to the pool's active_thins list and the pool lock is released. This opens a race with a worker thread that walks the list and calls thin_get/put, noticing that the refcount goes to 0 and calling complete, freezing up the system and giving the oops below: kernel: BUG: unable to handle kernel NULL pointer dereference at (null) kernel: IP: [<ffffffff810d360b>] __wake_up_common+0x2b/0x90 kernel: Call Trace: kernel: [<ffffffff810d3683>] __wake_up_locked+0x13/0x20 kernel: [<ffffffff810d3dc7>] complete+0x37/0x50 kernel: [<ffffffffa0595c50>] thin_put+0x20/0x30 [dm_thin_pool] kernel: [<ffffffffa059aab7>] do_worker+0x667/0x870 [dm_thin_pool] kernel: [<ffffffff816a8a4c>] ? __schedule+0x3ac/0x9a0 kernel: [<ffffffff810b1aef>] process_one_work+0x14f/0x400 kernel: [<ffffffff810b206b>] worker_thread+0x6b/0x490 kernel: [<ffffffff810b2000>] ? rescuer_thread+0x260/0x260 kernel: [<ffffffff810b6a7b>] kthread+0xdb/0x100 kernel: [<ffffffff810b69a0>] ? kthread_create_on_node+0x170/0x170 kernel: [<ffffffff816ad7ec>] ret_from_fork+0x7c/0xb0 kernel: [<ffffffff810b69a0>] ? kthread_create_on_node+0x170/0x170 Set the thin device's initial refcount and initialize the completion before adding it to the pool's active_thins list in thin_ctr(). Signed-off-by: Marc Dionne <marc.dionne@your-file-system.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-12-17 12:59:59 +00:00
atomic_set(&tc->refcount, 1);
init_completion(&tc->can_destroy);
list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
spin_unlock_irqrestore(&tc->pool->lock, flags);
/*
* This synchronize_rcu() call is needed here otherwise we risk a
* wake_worker() call finding no bios to process (because the newly
* added tc isn't yet visible). So this reduces latency since we
* aren't then dependent on the periodic commit to wake_worker().
*/
synchronize_rcu();
dm_put(pool_md);
return 0;
bad:
dm_pool_close_thin_device(tc->td);
bad_pool:
__pool_dec(tc->pool);
bad_pool_lookup:
dm_put(pool_md);
bad_common:
dm_put_device(ti, tc->pool_dev);
bad_pool_dev:
if (tc->origin_dev)
dm_put_device(ti, tc->origin_dev);
bad_origin_dev:
kfree(tc);
out_unlock:
mutex_unlock(&dm_thin_pool_table.mutex);
return r;
}
static int thin_map(struct dm_target *ti, struct bio *bio)
{
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
return thin_bio_map(ti, bio);
}
static int thin_endio(struct dm_target *ti, struct bio *bio,
blk_status_t *err)
{
unsigned long flags;
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
struct list_head work;
struct dm_thin_new_mapping *m, *tmp;
struct pool *pool = h->tc->pool;
if (h->shared_read_entry) {
INIT_LIST_HEAD(&work);
dm_deferred_entry_dec(h->shared_read_entry, &work);
spin_lock_irqsave(&pool->lock, flags);
list_for_each_entry_safe(m, tmp, &work, list) {
list_del(&m->list);
__complete_mapping_preparation(m);
}
spin_unlock_irqrestore(&pool->lock, flags);
}
if (h->all_io_entry) {
INIT_LIST_HEAD(&work);
dm_deferred_entry_dec(h->all_io_entry, &work);
if (!list_empty(&work)) {
spin_lock_irqsave(&pool->lock, flags);
list_for_each_entry_safe(m, tmp, &work, list)
list_add_tail(&m->list, &pool->prepared_discards);
spin_unlock_irqrestore(&pool->lock, flags);
wake_worker(pool);
}
}
if (h->cell)
cell_defer_no_holder(h->tc, h->cell);
return DM_ENDIO_DONE;
}
static void thin_presuspend(struct dm_target *ti)
{
struct thin_c *tc = ti->private;
if (dm_noflush_suspending(ti))
noflush_work(tc, do_noflush_start);
}
static void thin_postsuspend(struct dm_target *ti)
{
struct thin_c *tc = ti->private;
/*
* The dm_noflush_suspending flag has been cleared by now, so
* unfortunately we must always run this.
*/
noflush_work(tc, do_noflush_stop);
}
static int thin_preresume(struct dm_target *ti)
{
struct thin_c *tc = ti->private;
if (tc->origin_dev)
tc->origin_size = get_dev_size(tc->origin_dev->bdev);
return 0;
}
/*
* <nr mapped sectors> <highest mapped sector>
*/
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
static void thin_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
int r;
ssize_t sz = 0;
dm_block_t mapped, highest;
char buf[BDEVNAME_SIZE];
struct thin_c *tc = ti->private;
if (get_pool_mode(tc->pool) == PM_FAIL) {
DMEMIT("Fail");
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
return;
}
if (!tc->td)
DMEMIT("-");
else {
switch (type) {
case STATUSTYPE_INFO:
r = dm_thin_get_mapped_count(tc->td, &mapped);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
if (r) {
DMERR("dm_thin_get_mapped_count returned %d", r);
goto err;
}
r = dm_thin_get_highest_mapped_block(tc->td, &highest);
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
if (r < 0) {
DMERR("dm_thin_get_highest_mapped_block returned %d", r);
goto err;
}
DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
if (r)
DMEMIT("%llu", ((highest + 1) *
tc->pool->sectors_per_block) - 1);
else
DMEMIT("-");
break;
case STATUSTYPE_TABLE:
DMEMIT("%s %lu",
format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
(unsigned long) tc->dev_id);
if (tc->origin_dev)
DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
break;
}
}
dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:44 +00:00
return;
err:
DMEMIT("Error");
}
static int thin_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
sector_t blocks;
struct thin_c *tc = ti->private;
struct pool *pool = tc->pool;
/*
* We can't call dm_pool_get_data_dev_size() since that blocks. So
* we follow a more convoluted path through to the pool's target.
*/
if (!pool->ti)
return 0; /* nothing is bound */
blocks = pool->ti->len;
(void) sector_div(blocks, pool->sectors_per_block);
if (blocks)
return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
return 0;
}
static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct thin_c *tc = ti->private;
struct pool *pool = tc->pool;
if (!pool->pf.discard_enabled)
return;
limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */
}
static struct target_type thin_target = {
.name = "thin",
.version = {1, 19, 0},
.module = THIS_MODULE,
.ctr = thin_ctr,
.dtr = thin_dtr,
.map = thin_map,
.end_io = thin_endio,
.preresume = thin_preresume,
.presuspend = thin_presuspend,
.postsuspend = thin_postsuspend,
.status = thin_status,
.iterate_devices = thin_iterate_devices,
.io_hints = thin_io_hints,
};
/*----------------------------------------------------------------*/
static int __init dm_thin_init(void)
{
dm: fix various targets to dm_register_target after module __init resources created A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>" processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Cc: stable@vger.kernel.org Signed-off-by: monty <monty_pavel@sina.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-24 17:43:50 +00:00
int r = -ENOMEM;
pool_table_init();
dm: fix various targets to dm_register_target after module __init resources created A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>" processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Cc: stable@vger.kernel.org Signed-off-by: monty <monty_pavel@sina.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-24 17:43:50 +00:00
_new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
if (!_new_mapping_cache)
return r;
r = dm_register_target(&thin_target);
if (r)
dm: fix various targets to dm_register_target after module __init resources created A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>" processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Cc: stable@vger.kernel.org Signed-off-by: monty <monty_pavel@sina.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-24 17:43:50 +00:00
goto bad_new_mapping_cache;
r = dm_register_target(&pool_target);
if (r)
dm: fix various targets to dm_register_target after module __init resources created A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>" processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Cc: stable@vger.kernel.org Signed-off-by: monty <monty_pavel@sina.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-24 17:43:50 +00:00
goto bad_thin_target;
return 0;
dm: fix various targets to dm_register_target after module __init resources created A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>" processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Cc: stable@vger.kernel.org Signed-off-by: monty <monty_pavel@sina.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-24 17:43:50 +00:00
bad_thin_target:
dm_unregister_target(&thin_target);
dm: fix various targets to dm_register_target after module __init resources created A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>" processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Cc: stable@vger.kernel.org Signed-off-by: monty <monty_pavel@sina.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-24 17:43:50 +00:00
bad_new_mapping_cache:
kmem_cache_destroy(_new_mapping_cache);
return r;
}
static void dm_thin_exit(void)
{
dm_unregister_target(&thin_target);
dm_unregister_target(&pool_target);
kmem_cache_destroy(_new_mapping_cache);
pool_table_exit();
}
module_init(dm_thin_init);
module_exit(dm_thin_exit);
module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");