linux/fs/btrfs/raid56.c
Linus Torvalds 353767e4aa for-5.20-tag
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Merge tag 'for-5.20-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "This brings some long awaited changes, the send protocol bump,
  otherwise lots of small improvements and fixes. The main core part is
  reworking bio handling, cleaning up the submission and endio and
  improving error handling.

  There are some changes outside of btrfs adding helpers or updating
  API, listed at the end of the changelog.

  Features:

   - sysfs:
      - export chunk size, in debug mode add tunable for setting its size
      - show zoned among features (was only in debug mode)
      - show commit stats (number, last/max/total duration)

   - send protocol updated to 2
      - new commands:
         - ability write larger data chunks than 64K
         - send raw compressed extents (uses the encoded data ioctls),
           ie. no decompression on send side, no compression needed on
           receive side if supported
         - send 'otime' (inode creation time) among other timestamps
         - send file attributes (a.k.a file flags and xflags)
      - this is first version bump, backward compatibility on send and
        receive side is provided
      - there are still some known and wanted commands that will be
        implemented in the near future, another version bump will be
        needed, however we want to minimize that to avoid causing
        usability issues

   - print checksum type and implementation at mount time

   - don't print some messages at mount (mentioned as people asked about
     it), we want to print messages namely for new features so let's
     make some space for that
      - big metadata - this has been supported for a long time and is
        not a feature that's worth mentioning
      - skinny metadata - same reason, set by default by mkfs

  Performance improvements:

   - reduced amount of reserved metadata for delayed items
      - when inserted items can be batched into one leaf
      - when deleting batched directory index items
      - when deleting delayed items used for deletion
      - overall improved count of files/sec, decreased subvolume lock
        contention

   - metadata item access bounds checker micro-optimized, with a few
     percent of improved runtime for metadata-heavy operations

   - increase direct io limit for read to 256 sectors, improved
     throughput by 3x on sample workload

  Notable fixes:

   - raid56
      - reduce parity writes, skip sectors of stripe when there are no
        data updates
      - restore reading from on-disk data instead of using stripe cache,
        this reduces chances to damage correct data due to RMW cycle

   - refuse to replay log with unknown incompat read-only feature bit
     set

   - zoned
      - fix page locking when COW fails in the middle of allocation
      - improved tracking of active zones, ZNS drives may limit the
        number and there are ENOSPC errors due to that limit and not
        actual lack of space
      - adjust maximum extent size for zone append so it does not cause
        late ENOSPC due to underreservation

   - mirror reading error messages show the mirror number

   - don't fallback to buffered IO for NOWAIT direct IO writes, we don't
     have the NOWAIT semantics for buffered io yet

   - send, fix sending link commands for existing file paths when there
     are deleted and created hardlinks for same files

   - repair all mirrors for profiles with more than 1 copy (raid1c34)

   - fix repair of compressed extents, unify where error detection and
     repair happen

  Core changes:

   - bio completion cleanups
      - don't double defer compression bios
      - simplify endio workqueues
      - add more data to btrfs_bio to avoid allocation for read requests
      - rework bio error handling so it's same what block layer does,
        the submission works and errors are consumed in endio
      - when asynchronous bio offload fails fall back to synchronous
        checksum calculation to avoid errors under writeback or memory
        pressure

   - new trace points
      - raid56 events
      - ordered extent operations

   - super block log_root_transid deprecated (never used)

   - mixed_backref and big_metadata sysfs feature files removed, they've
     been default for sufficiently long time, there are no known users
     and mixed_backref could be confused with mixed_groups

  Non-btrfs changes, API updates:

   - minor highmem API update to cover const arguments

   - switch all kmap/kmap_atomic to kmap_local

   - remove redundant flush_dcache_page()

   - address_space_operations::writepage callback removed

   - add bdev_max_segments() helper"

* tag 'for-5.20-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (163 commits)
  btrfs: don't call btrfs_page_set_checked in finish_compressed_bio_read
  btrfs: fix repair of compressed extents
  btrfs: remove the start argument to check_data_csum and export
  btrfs: pass a btrfs_bio to btrfs_repair_one_sector
  btrfs: simplify the pending I/O counting in struct compressed_bio
  btrfs: repair all known bad mirrors
  btrfs: merge btrfs_dev_stat_print_on_error with its only caller
  btrfs: join running log transaction when logging new name
  btrfs: simplify error handling in btrfs_lookup_dentry
  btrfs: send: always use the rbtree based inode ref management infrastructure
  btrfs: send: fix sending link commands for existing file paths
  btrfs: send: introduce recorded_ref_alloc and recorded_ref_free
  btrfs: zoned: wait until zone is finished when allocation didn't progress
  btrfs: zoned: write out partially allocated region
  btrfs: zoned: activate necessary block group
  btrfs: zoned: activate metadata block group on flush_space
  btrfs: zoned: disable metadata overcommit for zoned
  btrfs: zoned: introduce space_info->active_total_bytes
  btrfs: zoned: finish least available block group on data bg allocation
  btrfs: let can_allocate_chunk return error
  ...
2022-08-03 14:54:52 -07:00

2789 lines
73 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 Fusion-io All rights reserved.
* Copyright (C) 2012 Intel Corp. All rights reserved.
*/
#include <linux/sched.h>
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/raid/pq.h>
#include <linux/hash.h>
#include <linux/list_sort.h>
#include <linux/raid/xor.h>
#include <linux/mm.h>
#include "misc.h"
#include "ctree.h"
#include "disk-io.h"
#include "volumes.h"
#include "raid56.h"
#include "async-thread.h"
/* set when additional merges to this rbio are not allowed */
#define RBIO_RMW_LOCKED_BIT 1
/*
* set when this rbio is sitting in the hash, but it is just a cache
* of past RMW
*/
#define RBIO_CACHE_BIT 2
/*
* set when it is safe to trust the stripe_pages for caching
*/
#define RBIO_CACHE_READY_BIT 3
#define RBIO_CACHE_SIZE 1024
#define BTRFS_STRIPE_HASH_TABLE_BITS 11
/* Used by the raid56 code to lock stripes for read/modify/write */
struct btrfs_stripe_hash {
struct list_head hash_list;
spinlock_t lock;
};
/* Used by the raid56 code to lock stripes for read/modify/write */
struct btrfs_stripe_hash_table {
struct list_head stripe_cache;
spinlock_t cache_lock;
int cache_size;
struct btrfs_stripe_hash table[];
};
/*
* A bvec like structure to present a sector inside a page.
*
* Unlike bvec we don't need bvlen, as it's fixed to sectorsize.
*/
struct sector_ptr {
struct page *page;
unsigned int pgoff:24;
unsigned int uptodate:8;
};
static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
static void rmw_work(struct work_struct *work);
static void read_rebuild_work(struct work_struct *work);
static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
static void __free_raid_bio(struct btrfs_raid_bio *rbio);
static void index_rbio_pages(struct btrfs_raid_bio *rbio);
static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
int need_check);
static void scrub_parity_work(struct work_struct *work);
static void start_async_work(struct btrfs_raid_bio *rbio, work_func_t work_func)
{
INIT_WORK(&rbio->work, work_func);
queue_work(rbio->bioc->fs_info->rmw_workers, &rbio->work);
}
/*
* the stripe hash table is used for locking, and to collect
* bios in hopes of making a full stripe
*/
int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
{
struct btrfs_stripe_hash_table *table;
struct btrfs_stripe_hash_table *x;
struct btrfs_stripe_hash *cur;
struct btrfs_stripe_hash *h;
int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
int i;
if (info->stripe_hash_table)
return 0;
/*
* The table is large, starting with order 4 and can go as high as
* order 7 in case lock debugging is turned on.
*
* Try harder to allocate and fallback to vmalloc to lower the chance
* of a failing mount.
*/
table = kvzalloc(struct_size(table, table, num_entries), GFP_KERNEL);
if (!table)
return -ENOMEM;
spin_lock_init(&table->cache_lock);
INIT_LIST_HEAD(&table->stripe_cache);
h = table->table;
for (i = 0; i < num_entries; i++) {
cur = h + i;
INIT_LIST_HEAD(&cur->hash_list);
spin_lock_init(&cur->lock);
}
x = cmpxchg(&info->stripe_hash_table, NULL, table);
kvfree(x);
return 0;
}
/*
* caching an rbio means to copy anything from the
* bio_sectors array into the stripe_pages array. We
* use the page uptodate bit in the stripe cache array
* to indicate if it has valid data
*
* once the caching is done, we set the cache ready
* bit.
*/
static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
{
int i;
int ret;
ret = alloc_rbio_pages(rbio);
if (ret)
return;
for (i = 0; i < rbio->nr_sectors; i++) {
/* Some range not covered by bio (partial write), skip it */
if (!rbio->bio_sectors[i].page)
continue;
ASSERT(rbio->stripe_sectors[i].page);
memcpy_page(rbio->stripe_sectors[i].page,
rbio->stripe_sectors[i].pgoff,
rbio->bio_sectors[i].page,
rbio->bio_sectors[i].pgoff,
rbio->bioc->fs_info->sectorsize);
rbio->stripe_sectors[i].uptodate = 1;
}
set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
}
/*
* we hash on the first logical address of the stripe
*/
static int rbio_bucket(struct btrfs_raid_bio *rbio)
{
u64 num = rbio->bioc->raid_map[0];
/*
* we shift down quite a bit. We're using byte
* addressing, and most of the lower bits are zeros.
* This tends to upset hash_64, and it consistently
* returns just one or two different values.
*
* shifting off the lower bits fixes things.
*/
return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
}
static bool full_page_sectors_uptodate(struct btrfs_raid_bio *rbio,
unsigned int page_nr)
{
const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
const u32 sectors_per_page = PAGE_SIZE / sectorsize;
int i;
ASSERT(page_nr < rbio->nr_pages);
for (i = sectors_per_page * page_nr;
i < sectors_per_page * page_nr + sectors_per_page;
i++) {
if (!rbio->stripe_sectors[i].uptodate)
return false;
}
return true;
}
/*
* Update the stripe_sectors[] array to use correct page and pgoff
*
* Should be called every time any page pointer in stripes_pages[] got modified.
*/
static void index_stripe_sectors(struct btrfs_raid_bio *rbio)
{
const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
u32 offset;
int i;
for (i = 0, offset = 0; i < rbio->nr_sectors; i++, offset += sectorsize) {
int page_index = offset >> PAGE_SHIFT;
ASSERT(page_index < rbio->nr_pages);
rbio->stripe_sectors[i].page = rbio->stripe_pages[page_index];
rbio->stripe_sectors[i].pgoff = offset_in_page(offset);
}
}
static void steal_rbio_page(struct btrfs_raid_bio *src,
struct btrfs_raid_bio *dest, int page_nr)
{
const u32 sectorsize = src->bioc->fs_info->sectorsize;
const u32 sectors_per_page = PAGE_SIZE / sectorsize;
int i;
if (dest->stripe_pages[page_nr])
__free_page(dest->stripe_pages[page_nr]);
dest->stripe_pages[page_nr] = src->stripe_pages[page_nr];
src->stripe_pages[page_nr] = NULL;
/* Also update the sector->uptodate bits. */
for (i = sectors_per_page * page_nr;
i < sectors_per_page * page_nr + sectors_per_page; i++)
dest->stripe_sectors[i].uptodate = true;
}
/*
* Stealing an rbio means taking all the uptodate pages from the stripe array
* in the source rbio and putting them into the destination rbio.
*
* This will also update the involved stripe_sectors[] which are referring to
* the old pages.
*/
static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
{
int i;
struct page *s;
if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
return;
for (i = 0; i < dest->nr_pages; i++) {
s = src->stripe_pages[i];
if (!s || !full_page_sectors_uptodate(src, i))
continue;
steal_rbio_page(src, dest, i);
}
index_stripe_sectors(dest);
index_stripe_sectors(src);
}
/*
* merging means we take the bio_list from the victim and
* splice it into the destination. The victim should
* be discarded afterwards.
*
* must be called with dest->rbio_list_lock held
*/
static void merge_rbio(struct btrfs_raid_bio *dest,
struct btrfs_raid_bio *victim)
{
bio_list_merge(&dest->bio_list, &victim->bio_list);
dest->bio_list_bytes += victim->bio_list_bytes;
/* Also inherit the bitmaps from @victim. */
bitmap_or(&dest->dbitmap, &victim->dbitmap, &dest->dbitmap,
dest->stripe_nsectors);
dest->generic_bio_cnt += victim->generic_bio_cnt;
bio_list_init(&victim->bio_list);
}
/*
* used to prune items that are in the cache. The caller
* must hold the hash table lock.
*/
static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
{
int bucket = rbio_bucket(rbio);
struct btrfs_stripe_hash_table *table;
struct btrfs_stripe_hash *h;
int freeit = 0;
/*
* check the bit again under the hash table lock.
*/
if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
return;
table = rbio->bioc->fs_info->stripe_hash_table;
h = table->table + bucket;
/* hold the lock for the bucket because we may be
* removing it from the hash table
*/
spin_lock(&h->lock);
/*
* hold the lock for the bio list because we need
* to make sure the bio list is empty
*/
spin_lock(&rbio->bio_list_lock);
if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
list_del_init(&rbio->stripe_cache);
table->cache_size -= 1;
freeit = 1;
/* if the bio list isn't empty, this rbio is
* still involved in an IO. We take it out
* of the cache list, and drop the ref that
* was held for the list.
*
* If the bio_list was empty, we also remove
* the rbio from the hash_table, and drop
* the corresponding ref
*/
if (bio_list_empty(&rbio->bio_list)) {
if (!list_empty(&rbio->hash_list)) {
list_del_init(&rbio->hash_list);
refcount_dec(&rbio->refs);
BUG_ON(!list_empty(&rbio->plug_list));
}
}
}
spin_unlock(&rbio->bio_list_lock);
spin_unlock(&h->lock);
if (freeit)
__free_raid_bio(rbio);
}
/*
* prune a given rbio from the cache
*/
static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
{
struct btrfs_stripe_hash_table *table;
unsigned long flags;
if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
return;
table = rbio->bioc->fs_info->stripe_hash_table;
spin_lock_irqsave(&table->cache_lock, flags);
__remove_rbio_from_cache(rbio);
spin_unlock_irqrestore(&table->cache_lock, flags);
}
/*
* remove everything in the cache
*/
static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
{
struct btrfs_stripe_hash_table *table;
unsigned long flags;
struct btrfs_raid_bio *rbio;
table = info->stripe_hash_table;
spin_lock_irqsave(&table->cache_lock, flags);
while (!list_empty(&table->stripe_cache)) {
rbio = list_entry(table->stripe_cache.next,
struct btrfs_raid_bio,
stripe_cache);
__remove_rbio_from_cache(rbio);
}
spin_unlock_irqrestore(&table->cache_lock, flags);
}
/*
* remove all cached entries and free the hash table
* used by unmount
*/
void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
{
if (!info->stripe_hash_table)
return;
btrfs_clear_rbio_cache(info);
kvfree(info->stripe_hash_table);
info->stripe_hash_table = NULL;
}
/*
* insert an rbio into the stripe cache. It
* must have already been prepared by calling
* cache_rbio_pages
*
* If this rbio was already cached, it gets
* moved to the front of the lru.
*
* If the size of the rbio cache is too big, we
* prune an item.
*/
static void cache_rbio(struct btrfs_raid_bio *rbio)
{
struct btrfs_stripe_hash_table *table;
unsigned long flags;
if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
return;
table = rbio->bioc->fs_info->stripe_hash_table;
spin_lock_irqsave(&table->cache_lock, flags);
spin_lock(&rbio->bio_list_lock);
/* bump our ref if we were not in the list before */
if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
refcount_inc(&rbio->refs);
if (!list_empty(&rbio->stripe_cache)){
list_move(&rbio->stripe_cache, &table->stripe_cache);
} else {
list_add(&rbio->stripe_cache, &table->stripe_cache);
table->cache_size += 1;
}
spin_unlock(&rbio->bio_list_lock);
if (table->cache_size > RBIO_CACHE_SIZE) {
struct btrfs_raid_bio *found;
found = list_entry(table->stripe_cache.prev,
struct btrfs_raid_bio,
stripe_cache);
if (found != rbio)
__remove_rbio_from_cache(found);
}
spin_unlock_irqrestore(&table->cache_lock, flags);
}
/*
* helper function to run the xor_blocks api. It is only
* able to do MAX_XOR_BLOCKS at a time, so we need to
* loop through.
*/
static void run_xor(void **pages, int src_cnt, ssize_t len)
{
int src_off = 0;
int xor_src_cnt = 0;
void *dest = pages[src_cnt];
while(src_cnt > 0) {
xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
xor_blocks(xor_src_cnt, len, dest, pages + src_off);
src_cnt -= xor_src_cnt;
src_off += xor_src_cnt;
}
}
/*
* Returns true if the bio list inside this rbio covers an entire stripe (no
* rmw required).
*/
static int rbio_is_full(struct btrfs_raid_bio *rbio)
{
unsigned long flags;
unsigned long size = rbio->bio_list_bytes;
int ret = 1;
spin_lock_irqsave(&rbio->bio_list_lock, flags);
if (size != rbio->nr_data * BTRFS_STRIPE_LEN)
ret = 0;
BUG_ON(size > rbio->nr_data * BTRFS_STRIPE_LEN);
spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
return ret;
}
/*
* returns 1 if it is safe to merge two rbios together.
* The merging is safe if the two rbios correspond to
* the same stripe and if they are both going in the same
* direction (read vs write), and if neither one is
* locked for final IO
*
* The caller is responsible for locking such that
* rmw_locked is safe to test
*/
static int rbio_can_merge(struct btrfs_raid_bio *last,
struct btrfs_raid_bio *cur)
{
if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
return 0;
/*
* we can't merge with cached rbios, since the
* idea is that when we merge the destination
* rbio is going to run our IO for us. We can
* steal from cached rbios though, other functions
* handle that.
*/
if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
test_bit(RBIO_CACHE_BIT, &cur->flags))
return 0;
if (last->bioc->raid_map[0] != cur->bioc->raid_map[0])
return 0;
/* we can't merge with different operations */
if (last->operation != cur->operation)
return 0;
/*
* We've need read the full stripe from the drive.
* check and repair the parity and write the new results.
*
* We're not allowed to add any new bios to the
* bio list here, anyone else that wants to
* change this stripe needs to do their own rmw.
*/
if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
return 0;
if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
return 0;
if (last->operation == BTRFS_RBIO_READ_REBUILD) {
int fa = last->faila;
int fb = last->failb;
int cur_fa = cur->faila;
int cur_fb = cur->failb;
if (last->faila >= last->failb) {
fa = last->failb;
fb = last->faila;
}
if (cur->faila >= cur->failb) {
cur_fa = cur->failb;
cur_fb = cur->faila;
}
if (fa != cur_fa || fb != cur_fb)
return 0;
}
return 1;
}
static unsigned int rbio_stripe_sector_index(const struct btrfs_raid_bio *rbio,
unsigned int stripe_nr,
unsigned int sector_nr)
{
ASSERT(stripe_nr < rbio->real_stripes);
ASSERT(sector_nr < rbio->stripe_nsectors);
return stripe_nr * rbio->stripe_nsectors + sector_nr;
}
/* Return a sector from rbio->stripe_sectors, not from the bio list */
static struct sector_ptr *rbio_stripe_sector(const struct btrfs_raid_bio *rbio,
unsigned int stripe_nr,
unsigned int sector_nr)
{
return &rbio->stripe_sectors[rbio_stripe_sector_index(rbio, stripe_nr,
sector_nr)];
}
/* Grab a sector inside P stripe */
static struct sector_ptr *rbio_pstripe_sector(const struct btrfs_raid_bio *rbio,
unsigned int sector_nr)
{
return rbio_stripe_sector(rbio, rbio->nr_data, sector_nr);
}
/* Grab a sector inside Q stripe, return NULL if not RAID6 */
static struct sector_ptr *rbio_qstripe_sector(const struct btrfs_raid_bio *rbio,
unsigned int sector_nr)
{
if (rbio->nr_data + 1 == rbio->real_stripes)
return NULL;
return rbio_stripe_sector(rbio, rbio->nr_data + 1, sector_nr);
}
/*
* The first stripe in the table for a logical address
* has the lock. rbios are added in one of three ways:
*
* 1) Nobody has the stripe locked yet. The rbio is given
* the lock and 0 is returned. The caller must start the IO
* themselves.
*
* 2) Someone has the stripe locked, but we're able to merge
* with the lock owner. The rbio is freed and the IO will
* start automatically along with the existing rbio. 1 is returned.
*
* 3) Someone has the stripe locked, but we're not able to merge.
* The rbio is added to the lock owner's plug list, or merged into
* an rbio already on the plug list. When the lock owner unlocks,
* the next rbio on the list is run and the IO is started automatically.
* 1 is returned
*
* If we return 0, the caller still owns the rbio and must continue with
* IO submission. If we return 1, the caller must assume the rbio has
* already been freed.
*/
static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
{
struct btrfs_stripe_hash *h;
struct btrfs_raid_bio *cur;
struct btrfs_raid_bio *pending;
unsigned long flags;
struct btrfs_raid_bio *freeit = NULL;
struct btrfs_raid_bio *cache_drop = NULL;
int ret = 0;
h = rbio->bioc->fs_info->stripe_hash_table->table + rbio_bucket(rbio);
spin_lock_irqsave(&h->lock, flags);
list_for_each_entry(cur, &h->hash_list, hash_list) {
if (cur->bioc->raid_map[0] != rbio->bioc->raid_map[0])
continue;
spin_lock(&cur->bio_list_lock);
/* Can we steal this cached rbio's pages? */
if (bio_list_empty(&cur->bio_list) &&
list_empty(&cur->plug_list) &&
test_bit(RBIO_CACHE_BIT, &cur->flags) &&
!test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
list_del_init(&cur->hash_list);
refcount_dec(&cur->refs);
steal_rbio(cur, rbio);
cache_drop = cur;
spin_unlock(&cur->bio_list_lock);
goto lockit;
}
/* Can we merge into the lock owner? */
if (rbio_can_merge(cur, rbio)) {
merge_rbio(cur, rbio);
spin_unlock(&cur->bio_list_lock);
freeit = rbio;
ret = 1;
goto out;
}
/*
* We couldn't merge with the running rbio, see if we can merge
* with the pending ones. We don't have to check for rmw_locked
* because there is no way they are inside finish_rmw right now
*/
list_for_each_entry(pending, &cur->plug_list, plug_list) {
if (rbio_can_merge(pending, rbio)) {
merge_rbio(pending, rbio);
spin_unlock(&cur->bio_list_lock);
freeit = rbio;
ret = 1;
goto out;
}
}
/*
* No merging, put us on the tail of the plug list, our rbio
* will be started with the currently running rbio unlocks
*/
list_add_tail(&rbio->plug_list, &cur->plug_list);
spin_unlock(&cur->bio_list_lock);
ret = 1;
goto out;
}
lockit:
refcount_inc(&rbio->refs);
list_add(&rbio->hash_list, &h->hash_list);
out:
spin_unlock_irqrestore(&h->lock, flags);
if (cache_drop)
remove_rbio_from_cache(cache_drop);
if (freeit)
__free_raid_bio(freeit);
return ret;
}
/*
* called as rmw or parity rebuild is completed. If the plug list has more
* rbios waiting for this stripe, the next one on the list will be started
*/
static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
{
int bucket;
struct btrfs_stripe_hash *h;
unsigned long flags;
int keep_cache = 0;
bucket = rbio_bucket(rbio);
h = rbio->bioc->fs_info->stripe_hash_table->table + bucket;
if (list_empty(&rbio->plug_list))
cache_rbio(rbio);
spin_lock_irqsave(&h->lock, flags);
spin_lock(&rbio->bio_list_lock);
if (!list_empty(&rbio->hash_list)) {
/*
* if we're still cached and there is no other IO
* to perform, just leave this rbio here for others
* to steal from later
*/
if (list_empty(&rbio->plug_list) &&
test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
keep_cache = 1;
clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
BUG_ON(!bio_list_empty(&rbio->bio_list));
goto done;
}
list_del_init(&rbio->hash_list);
refcount_dec(&rbio->refs);
/*
* we use the plug list to hold all the rbios
* waiting for the chance to lock this stripe.
* hand the lock over to one of them.
*/
if (!list_empty(&rbio->plug_list)) {
struct btrfs_raid_bio *next;
struct list_head *head = rbio->plug_list.next;
next = list_entry(head, struct btrfs_raid_bio,
plug_list);
list_del_init(&rbio->plug_list);
list_add(&next->hash_list, &h->hash_list);
refcount_inc(&next->refs);
spin_unlock(&rbio->bio_list_lock);
spin_unlock_irqrestore(&h->lock, flags);
if (next->operation == BTRFS_RBIO_READ_REBUILD)
start_async_work(next, read_rebuild_work);
else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
steal_rbio(rbio, next);
start_async_work(next, read_rebuild_work);
} else if (next->operation == BTRFS_RBIO_WRITE) {
steal_rbio(rbio, next);
start_async_work(next, rmw_work);
} else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
steal_rbio(rbio, next);
start_async_work(next, scrub_parity_work);
}
goto done_nolock;
}
}
done:
spin_unlock(&rbio->bio_list_lock);
spin_unlock_irqrestore(&h->lock, flags);
done_nolock:
if (!keep_cache)
remove_rbio_from_cache(rbio);
}
static void __free_raid_bio(struct btrfs_raid_bio *rbio)
{
int i;
if (!refcount_dec_and_test(&rbio->refs))
return;
WARN_ON(!list_empty(&rbio->stripe_cache));
WARN_ON(!list_empty(&rbio->hash_list));
WARN_ON(!bio_list_empty(&rbio->bio_list));
for (i = 0; i < rbio->nr_pages; i++) {
if (rbio->stripe_pages[i]) {
__free_page(rbio->stripe_pages[i]);
rbio->stripe_pages[i] = NULL;
}
}
btrfs_put_bioc(rbio->bioc);
kfree(rbio);
}
static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
{
struct bio *next;
while (cur) {
next = cur->bi_next;
cur->bi_next = NULL;
cur->bi_status = err;
bio_endio(cur);
cur = next;
}
}
/*
* this frees the rbio and runs through all the bios in the
* bio_list and calls end_io on them
*/
static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
{
struct bio *cur = bio_list_get(&rbio->bio_list);
struct bio *extra;
if (rbio->generic_bio_cnt)
btrfs_bio_counter_sub(rbio->bioc->fs_info, rbio->generic_bio_cnt);
/*
* Clear the data bitmap, as the rbio may be cached for later usage.
* do this before before unlock_stripe() so there will be no new bio
* for this bio.
*/
bitmap_clear(&rbio->dbitmap, 0, rbio->stripe_nsectors);
/*
* At this moment, rbio->bio_list is empty, however since rbio does not
* always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
* hash list, rbio may be merged with others so that rbio->bio_list
* becomes non-empty.
* Once unlock_stripe() is done, rbio->bio_list will not be updated any
* more and we can call bio_endio() on all queued bios.
*/
unlock_stripe(rbio);
extra = bio_list_get(&rbio->bio_list);
__free_raid_bio(rbio);
rbio_endio_bio_list(cur, err);
if (extra)
rbio_endio_bio_list(extra, err);
}
/*
* end io function used by finish_rmw. When we finally
* get here, we've written a full stripe
*/
static void raid_write_end_io(struct bio *bio)
{
struct btrfs_raid_bio *rbio = bio->bi_private;
blk_status_t err = bio->bi_status;
int max_errors;
if (err)
fail_bio_stripe(rbio, bio);
bio_put(bio);
if (!atomic_dec_and_test(&rbio->stripes_pending))
return;
err = BLK_STS_OK;
/* OK, we have read all the stripes we need to. */
max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ?
0 : rbio->bioc->max_errors;
if (atomic_read(&rbio->error) > max_errors)
err = BLK_STS_IOERR;
rbio_orig_end_io(rbio, err);
}
/**
* Get a sector pointer specified by its @stripe_nr and @sector_nr
*
* @rbio: The raid bio
* @stripe_nr: Stripe number, valid range [0, real_stripe)
* @sector_nr: Sector number inside the stripe,
* valid range [0, stripe_nsectors)
* @bio_list_only: Whether to use sectors inside the bio list only.
*
* The read/modify/write code wants to reuse the original bio page as much
* as possible, and only use stripe_sectors as fallback.
*/
static struct sector_ptr *sector_in_rbio(struct btrfs_raid_bio *rbio,
int stripe_nr, int sector_nr,
bool bio_list_only)
{
struct sector_ptr *sector;
int index;
ASSERT(stripe_nr >= 0 && stripe_nr < rbio->real_stripes);
ASSERT(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors);
index = stripe_nr * rbio->stripe_nsectors + sector_nr;
ASSERT(index >= 0 && index < rbio->nr_sectors);
spin_lock_irq(&rbio->bio_list_lock);
sector = &rbio->bio_sectors[index];
if (sector->page || bio_list_only) {
/* Don't return sector without a valid page pointer */
if (!sector->page)
sector = NULL;
spin_unlock_irq(&rbio->bio_list_lock);
return sector;
}
spin_unlock_irq(&rbio->bio_list_lock);
return &rbio->stripe_sectors[index];
}
/*
* allocation and initial setup for the btrfs_raid_bio. Not
* this does not allocate any pages for rbio->pages.
*/
static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
struct btrfs_io_context *bioc)
{
const unsigned int real_stripes = bioc->num_stripes - bioc->num_tgtdevs;
const unsigned int stripe_npages = BTRFS_STRIPE_LEN >> PAGE_SHIFT;
const unsigned int num_pages = stripe_npages * real_stripes;
const unsigned int stripe_nsectors =
BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits;
const unsigned int num_sectors = stripe_nsectors * real_stripes;
struct btrfs_raid_bio *rbio;
void *p;
/* PAGE_SIZE must also be aligned to sectorsize for subpage support */
ASSERT(IS_ALIGNED(PAGE_SIZE, fs_info->sectorsize));
/*
* Our current stripe len should be fixed to 64k thus stripe_nsectors
* (at most 16) should be no larger than BITS_PER_LONG.
*/
ASSERT(stripe_nsectors <= BITS_PER_LONG);
rbio = kzalloc(sizeof(*rbio) +
sizeof(*rbio->stripe_pages) * num_pages +
sizeof(*rbio->bio_sectors) * num_sectors +
sizeof(*rbio->stripe_sectors) * num_sectors +
sizeof(*rbio->finish_pointers) * real_stripes,
GFP_NOFS);
if (!rbio)
return ERR_PTR(-ENOMEM);
bio_list_init(&rbio->bio_list);
INIT_LIST_HEAD(&rbio->plug_list);
spin_lock_init(&rbio->bio_list_lock);
INIT_LIST_HEAD(&rbio->stripe_cache);
INIT_LIST_HEAD(&rbio->hash_list);
rbio->bioc = bioc;
rbio->nr_pages = num_pages;
rbio->nr_sectors = num_sectors;
rbio->real_stripes = real_stripes;
rbio->stripe_npages = stripe_npages;
rbio->stripe_nsectors = stripe_nsectors;
rbio->faila = -1;
rbio->failb = -1;
refcount_set(&rbio->refs, 1);
atomic_set(&rbio->error, 0);
atomic_set(&rbio->stripes_pending, 0);
/*
* The stripe_pages, bio_sectors, etc arrays point to the extra memory
* we allocated past the end of the rbio.
*/
p = rbio + 1;
#define CONSUME_ALLOC(ptr, count) do { \
ptr = p; \
p = (unsigned char *)p + sizeof(*(ptr)) * (count); \
} while (0)
CONSUME_ALLOC(rbio->stripe_pages, num_pages);
CONSUME_ALLOC(rbio->bio_sectors, num_sectors);
CONSUME_ALLOC(rbio->stripe_sectors, num_sectors);
CONSUME_ALLOC(rbio->finish_pointers, real_stripes);
#undef CONSUME_ALLOC
ASSERT(btrfs_nr_parity_stripes(bioc->map_type));
rbio->nr_data = real_stripes - btrfs_nr_parity_stripes(bioc->map_type);
return rbio;
}
/* allocate pages for all the stripes in the bio, including parity */
static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
{
int ret;
ret = btrfs_alloc_page_array(rbio->nr_pages, rbio->stripe_pages);
if (ret < 0)
return ret;
/* Mapping all sectors */
index_stripe_sectors(rbio);
return 0;
}
/* only allocate pages for p/q stripes */
static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
{
const int data_pages = rbio->nr_data * rbio->stripe_npages;
int ret;
ret = btrfs_alloc_page_array(rbio->nr_pages - data_pages,
rbio->stripe_pages + data_pages);
if (ret < 0)
return ret;
index_stripe_sectors(rbio);
return 0;
}
/*
* Add a single sector @sector into our list of bios for IO.
*
* Return 0 if everything went well.
* Return <0 for error.
*/
static int rbio_add_io_sector(struct btrfs_raid_bio *rbio,
struct bio_list *bio_list,
struct sector_ptr *sector,
unsigned int stripe_nr,
unsigned int sector_nr,
enum req_op op)
{
const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
struct bio *last = bio_list->tail;
int ret;
struct bio *bio;
struct btrfs_io_stripe *stripe;
u64 disk_start;
/*
* Note: here stripe_nr has taken device replace into consideration,
* thus it can be larger than rbio->real_stripe.
* So here we check against bioc->num_stripes, not rbio->real_stripes.
*/
ASSERT(stripe_nr >= 0 && stripe_nr < rbio->bioc->num_stripes);
ASSERT(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors);
ASSERT(sector->page);
stripe = &rbio->bioc->stripes[stripe_nr];
disk_start = stripe->physical + sector_nr * sectorsize;
/* if the device is missing, just fail this stripe */
if (!stripe->dev->bdev)
return fail_rbio_index(rbio, stripe_nr);
/* see if we can add this page onto our existing bio */
if (last) {
u64 last_end = last->bi_iter.bi_sector << 9;
last_end += last->bi_iter.bi_size;
/*
* we can't merge these if they are from different
* devices or if they are not contiguous
*/
if (last_end == disk_start && !last->bi_status &&
last->bi_bdev == stripe->dev->bdev) {
ret = bio_add_page(last, sector->page, sectorsize,
sector->pgoff);
if (ret == sectorsize)
return 0;
}
}
/* put a new bio on the list */
bio = bio_alloc(stripe->dev->bdev,
max(BTRFS_STRIPE_LEN >> PAGE_SHIFT, 1),
op, GFP_NOFS);
bio->bi_iter.bi_sector = disk_start >> 9;
bio->bi_private = rbio;
bio_add_page(bio, sector->page, sectorsize, sector->pgoff);
bio_list_add(bio_list, bio);
return 0;
}
/*
* while we're doing the read/modify/write cycle, we could
* have errors in reading pages off the disk. This checks
* for errors and if we're not able to read the page it'll
* trigger parity reconstruction. The rmw will be finished
* after we've reconstructed the failed stripes
*/
static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
{
if (rbio->faila >= 0 || rbio->failb >= 0) {
BUG_ON(rbio->faila == rbio->real_stripes - 1);
__raid56_parity_recover(rbio);
} else {
finish_rmw(rbio);
}
}
static void index_one_bio(struct btrfs_raid_bio *rbio, struct bio *bio)
{
const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
struct bio_vec bvec;
struct bvec_iter iter;
u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
rbio->bioc->raid_map[0];
bio_for_each_segment(bvec, bio, iter) {
u32 bvec_offset;
for (bvec_offset = 0; bvec_offset < bvec.bv_len;
bvec_offset += sectorsize, offset += sectorsize) {
int index = offset / sectorsize;
struct sector_ptr *sector = &rbio->bio_sectors[index];
sector->page = bvec.bv_page;
sector->pgoff = bvec.bv_offset + bvec_offset;
ASSERT(sector->pgoff < PAGE_SIZE);
}
}
}
/*
* helper function to walk our bio list and populate the bio_pages array with
* the result. This seems expensive, but it is faster than constantly
* searching through the bio list as we setup the IO in finish_rmw or stripe
* reconstruction.
*
* This must be called before you trust the answers from page_in_rbio
*/
static void index_rbio_pages(struct btrfs_raid_bio *rbio)
{
struct bio *bio;
spin_lock_irq(&rbio->bio_list_lock);
bio_list_for_each(bio, &rbio->bio_list)
index_one_bio(rbio, bio);
spin_unlock_irq(&rbio->bio_list_lock);
}
static void bio_get_trace_info(struct btrfs_raid_bio *rbio, struct bio *bio,
struct raid56_bio_trace_info *trace_info)
{
const struct btrfs_io_context *bioc = rbio->bioc;
int i;
ASSERT(bioc);
/* We rely on bio->bi_bdev to find the stripe number. */
if (!bio->bi_bdev)
goto not_found;
for (i = 0; i < bioc->num_stripes; i++) {
if (bio->bi_bdev != bioc->stripes[i].dev->bdev)
continue;
trace_info->stripe_nr = i;
trace_info->devid = bioc->stripes[i].dev->devid;
trace_info->offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
bioc->stripes[i].physical;
return;
}
not_found:
trace_info->devid = -1;
trace_info->offset = -1;
trace_info->stripe_nr = -1;
}
/*
* this is called from one of two situations. We either
* have a full stripe from the higher layers, or we've read all
* the missing bits off disk.
*
* This will calculate the parity and then send down any
* changed blocks.
*/
static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
{
struct btrfs_io_context *bioc = rbio->bioc;
const u32 sectorsize = bioc->fs_info->sectorsize;
void **pointers = rbio->finish_pointers;
int nr_data = rbio->nr_data;
/* The total sector number inside the full stripe. */
int total_sector_nr;
int stripe;
/* Sector number inside a stripe. */
int sectornr;
bool has_qstripe;
struct bio_list bio_list;
struct bio *bio;
int ret;
bio_list_init(&bio_list);
if (rbio->real_stripes - rbio->nr_data == 1)
has_qstripe = false;
else if (rbio->real_stripes - rbio->nr_data == 2)
has_qstripe = true;
else
BUG();
/* We should have at least one data sector. */
ASSERT(bitmap_weight(&rbio->dbitmap, rbio->stripe_nsectors));
/* at this point we either have a full stripe,
* or we've read the full stripe from the drive.
* recalculate the parity and write the new results.
*
* We're not allowed to add any new bios to the
* bio list here, anyone else that wants to
* change this stripe needs to do their own rmw.
*/
spin_lock_irq(&rbio->bio_list_lock);
set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
spin_unlock_irq(&rbio->bio_list_lock);
atomic_set(&rbio->error, 0);
/*
* now that we've set rmw_locked, run through the
* bio list one last time and map the page pointers
*
* We don't cache full rbios because we're assuming
* the higher layers are unlikely to use this area of
* the disk again soon. If they do use it again,
* hopefully they will send another full bio.
*/
index_rbio_pages(rbio);
if (!rbio_is_full(rbio))
cache_rbio_pages(rbio);
else
clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
struct sector_ptr *sector;
/* First collect one sector from each data stripe */
for (stripe = 0; stripe < nr_data; stripe++) {
sector = sector_in_rbio(rbio, stripe, sectornr, 0);
pointers[stripe] = kmap_local_page(sector->page) +
sector->pgoff;
}
/* Then add the parity stripe */
sector = rbio_pstripe_sector(rbio, sectornr);
sector->uptodate = 1;
pointers[stripe++] = kmap_local_page(sector->page) + sector->pgoff;
if (has_qstripe) {
/*
* RAID6, add the qstripe and call the library function
* to fill in our p/q
*/
sector = rbio_qstripe_sector(rbio, sectornr);
sector->uptodate = 1;
pointers[stripe++] = kmap_local_page(sector->page) +
sector->pgoff;
raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,
pointers);
} else {
/* raid5 */
memcpy(pointers[nr_data], pointers[0], sectorsize);
run_xor(pointers + 1, nr_data - 1, sectorsize);
}
for (stripe = stripe - 1; stripe >= 0; stripe--)
kunmap_local(pointers[stripe]);
}
/*
* Start writing. Make bios for everything from the higher layers (the
* bio_list in our rbio) and our P/Q. Ignore everything else.
*/
for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
total_sector_nr++) {
struct sector_ptr *sector;
stripe = total_sector_nr / rbio->stripe_nsectors;
sectornr = total_sector_nr % rbio->stripe_nsectors;
/* This vertical stripe has no data, skip it. */
if (!test_bit(sectornr, &rbio->dbitmap))
continue;
if (stripe < rbio->nr_data) {
sector = sector_in_rbio(rbio, stripe, sectornr, 1);
if (!sector)
continue;
} else {
sector = rbio_stripe_sector(rbio, stripe, sectornr);
}
ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,
sectornr, REQ_OP_WRITE);
if (ret)
goto cleanup;
}
if (likely(!bioc->num_tgtdevs))
goto write_data;
for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
total_sector_nr++) {
struct sector_ptr *sector;
stripe = total_sector_nr / rbio->stripe_nsectors;
sectornr = total_sector_nr % rbio->stripe_nsectors;
if (!bioc->tgtdev_map[stripe]) {
/*
* We can skip the whole stripe completely, note
* total_sector_nr will be increased by one anyway.
*/
ASSERT(sectornr == 0);
total_sector_nr += rbio->stripe_nsectors - 1;
continue;
}
/* This vertical stripe has no data, skip it. */
if (!test_bit(sectornr, &rbio->dbitmap))
continue;
if (stripe < rbio->nr_data) {
sector = sector_in_rbio(rbio, stripe, sectornr, 1);
if (!sector)
continue;
} else {
sector = rbio_stripe_sector(rbio, stripe, sectornr);
}
ret = rbio_add_io_sector(rbio, &bio_list, sector,
rbio->bioc->tgtdev_map[stripe],
sectornr, REQ_OP_WRITE);
if (ret)
goto cleanup;
}
write_data:
atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list));
BUG_ON(atomic_read(&rbio->stripes_pending) == 0);
while ((bio = bio_list_pop(&bio_list))) {
bio->bi_end_io = raid_write_end_io;
if (trace_raid56_write_stripe_enabled()) {
struct raid56_bio_trace_info trace_info = { 0 };
bio_get_trace_info(rbio, bio, &trace_info);
trace_raid56_write_stripe(rbio, bio, &trace_info);
}
submit_bio(bio);
}
return;
cleanup:
rbio_orig_end_io(rbio, BLK_STS_IOERR);
while ((bio = bio_list_pop(&bio_list)))
bio_put(bio);
}
/*
* helper to find the stripe number for a given bio. Used to figure out which
* stripe has failed. This expects the bio to correspond to a physical disk,
* so it looks up based on physical sector numbers.
*/
static int find_bio_stripe(struct btrfs_raid_bio *rbio,
struct bio *bio)
{
u64 physical = bio->bi_iter.bi_sector;
int i;
struct btrfs_io_stripe *stripe;
physical <<= 9;
for (i = 0; i < rbio->bioc->num_stripes; i++) {
stripe = &rbio->bioc->stripes[i];
if (in_range(physical, stripe->physical, BTRFS_STRIPE_LEN) &&
stripe->dev->bdev && bio->bi_bdev == stripe->dev->bdev) {
return i;
}
}
return -1;
}
/*
* helper to find the stripe number for a given
* bio (before mapping). Used to figure out which stripe has
* failed. This looks up based on logical block numbers.
*/
static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
struct bio *bio)
{
u64 logical = bio->bi_iter.bi_sector << 9;
int i;
for (i = 0; i < rbio->nr_data; i++) {
u64 stripe_start = rbio->bioc->raid_map[i];
if (in_range(logical, stripe_start, BTRFS_STRIPE_LEN))
return i;
}
return -1;
}
/*
* returns -EIO if we had too many failures
*/
static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&rbio->bio_list_lock, flags);
/* we already know this stripe is bad, move on */
if (rbio->faila == failed || rbio->failb == failed)
goto out;
if (rbio->faila == -1) {
/* first failure on this rbio */
rbio->faila = failed;
atomic_inc(&rbio->error);
} else if (rbio->failb == -1) {
/* second failure on this rbio */
rbio->failb = failed;
atomic_inc(&rbio->error);
} else {
ret = -EIO;
}
out:
spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
return ret;
}
/*
* helper to fail a stripe based on a physical disk
* bio.
*/
static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
struct bio *bio)
{
int failed = find_bio_stripe(rbio, bio);
if (failed < 0)
return -EIO;
return fail_rbio_index(rbio, failed);
}
/*
* For subpage case, we can no longer set page Uptodate directly for
* stripe_pages[], thus we need to locate the sector.
*/
static struct sector_ptr *find_stripe_sector(struct btrfs_raid_bio *rbio,
struct page *page,
unsigned int pgoff)
{
int i;
for (i = 0; i < rbio->nr_sectors; i++) {
struct sector_ptr *sector = &rbio->stripe_sectors[i];
if (sector->page == page && sector->pgoff == pgoff)
return sector;
}
return NULL;
}
/*
* this sets each page in the bio uptodate. It should only be used on private
* rbio pages, nothing that comes in from the higher layers
*/
static void set_bio_pages_uptodate(struct btrfs_raid_bio *rbio, struct bio *bio)
{
const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
struct bio_vec *bvec;
struct bvec_iter_all iter_all;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_segment_all(bvec, bio, iter_all) {
struct sector_ptr *sector;
int pgoff;
for (pgoff = bvec->bv_offset; pgoff - bvec->bv_offset < bvec->bv_len;
pgoff += sectorsize) {
sector = find_stripe_sector(rbio, bvec->bv_page, pgoff);
ASSERT(sector);
if (sector)
sector->uptodate = 1;
}
}
}
static void raid56_bio_end_io(struct bio *bio)
{
struct btrfs_raid_bio *rbio = bio->bi_private;
if (bio->bi_status)
fail_bio_stripe(rbio, bio);
else
set_bio_pages_uptodate(rbio, bio);
bio_put(bio);
if (atomic_dec_and_test(&rbio->stripes_pending))
queue_work(rbio->bioc->fs_info->endio_raid56_workers,
&rbio->end_io_work);
}
/*
* End io handler for the read phase of the RMW cycle. All the bios here are
* physical stripe bios we've read from the disk so we can recalculate the
* parity of the stripe.
*
* This will usually kick off finish_rmw once all the bios are read in, but it
* may trigger parity reconstruction if we had any errors along the way
*/
static void raid56_rmw_end_io_work(struct work_struct *work)
{
struct btrfs_raid_bio *rbio =
container_of(work, struct btrfs_raid_bio, end_io_work);
if (atomic_read(&rbio->error) > rbio->bioc->max_errors) {
rbio_orig_end_io(rbio, BLK_STS_IOERR);
return;
}
/*
* This will normally call finish_rmw to start our write but if there
* are any failed stripes we'll reconstruct from parity first.
*/
validate_rbio_for_rmw(rbio);
}
/*
* the stripe must be locked by the caller. It will
* unlock after all the writes are done
*/
static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
{
int bios_to_read = 0;
struct bio_list bio_list;
const int nr_data_sectors = rbio->stripe_nsectors * rbio->nr_data;
int ret;
int total_sector_nr;
struct bio *bio;
bio_list_init(&bio_list);
ret = alloc_rbio_pages(rbio);
if (ret)
goto cleanup;
index_rbio_pages(rbio);
atomic_set(&rbio->error, 0);
/* Build a list of bios to read all the missing data sectors. */
for (total_sector_nr = 0; total_sector_nr < nr_data_sectors;
total_sector_nr++) {
struct sector_ptr *sector;
int stripe = total_sector_nr / rbio->stripe_nsectors;
int sectornr = total_sector_nr % rbio->stripe_nsectors;
/*
* We want to find all the sectors missing from the rbio and
* read them from the disk. If sector_in_rbio() finds a page
* in the bio list we don't need to read it off the stripe.
*/
sector = sector_in_rbio(rbio, stripe, sectornr, 1);
if (sector)
continue;
sector = rbio_stripe_sector(rbio, stripe, sectornr);
/*
* The bio cache may have handed us an uptodate page. If so,
* use it.
*/
if (sector->uptodate)
continue;
ret = rbio_add_io_sector(rbio, &bio_list, sector,
stripe, sectornr, REQ_OP_READ);
if (ret)
goto cleanup;
}
bios_to_read = bio_list_size(&bio_list);
if (!bios_to_read) {
/*
* this can happen if others have merged with
* us, it means there is nothing left to read.
* But if there are missing devices it may not be
* safe to do the full stripe write yet.
*/
goto finish;
}
/*
* The bioc may be freed once we submit the last bio. Make sure not to
* touch it after that.
*/
atomic_set(&rbio->stripes_pending, bios_to_read);
INIT_WORK(&rbio->end_io_work, raid56_rmw_end_io_work);
while ((bio = bio_list_pop(&bio_list))) {
bio->bi_end_io = raid56_bio_end_io;
if (trace_raid56_read_partial_enabled()) {
struct raid56_bio_trace_info trace_info = { 0 };
bio_get_trace_info(rbio, bio, &trace_info);
trace_raid56_read_partial(rbio, bio, &trace_info);
}
submit_bio(bio);
}
/* the actual write will happen once the reads are done */
return 0;
cleanup:
rbio_orig_end_io(rbio, BLK_STS_IOERR);
while ((bio = bio_list_pop(&bio_list)))
bio_put(bio);
return -EIO;
finish:
validate_rbio_for_rmw(rbio);
return 0;
}
/*
* if the upper layers pass in a full stripe, we thank them by only allocating
* enough pages to hold the parity, and sending it all down quickly.
*/
static int full_stripe_write(struct btrfs_raid_bio *rbio)
{
int ret;
ret = alloc_rbio_parity_pages(rbio);
if (ret) {
__free_raid_bio(rbio);
return ret;
}
ret = lock_stripe_add(rbio);
if (ret == 0)
finish_rmw(rbio);
return 0;
}
/*
* partial stripe writes get handed over to async helpers.
* We're really hoping to merge a few more writes into this
* rbio before calculating new parity
*/
static int partial_stripe_write(struct btrfs_raid_bio *rbio)
{
int ret;
ret = lock_stripe_add(rbio);
if (ret == 0)
start_async_work(rbio, rmw_work);
return 0;
}
/*
* sometimes while we were reading from the drive to
* recalculate parity, enough new bios come into create
* a full stripe. So we do a check here to see if we can
* go directly to finish_rmw
*/
static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
{
/* head off into rmw land if we don't have a full stripe */
if (!rbio_is_full(rbio))
return partial_stripe_write(rbio);
return full_stripe_write(rbio);
}
/*
* We use plugging call backs to collect full stripes.
* Any time we get a partial stripe write while plugged
* we collect it into a list. When the unplug comes down,
* we sort the list by logical block number and merge
* everything we can into the same rbios
*/
struct btrfs_plug_cb {
struct blk_plug_cb cb;
struct btrfs_fs_info *info;
struct list_head rbio_list;
struct work_struct work;
};
/*
* rbios on the plug list are sorted for easier merging.
*/
static int plug_cmp(void *priv, const struct list_head *a,
const struct list_head *b)
{
const struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
plug_list);
const struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
plug_list);
u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
if (a_sector < b_sector)
return -1;
if (a_sector > b_sector)
return 1;
return 0;
}
static void run_plug(struct btrfs_plug_cb *plug)
{
struct btrfs_raid_bio *cur;
struct btrfs_raid_bio *last = NULL;
/*
* sort our plug list then try to merge
* everything we can in hopes of creating full
* stripes.
*/
list_sort(NULL, &plug->rbio_list, plug_cmp);
while (!list_empty(&plug->rbio_list)) {
cur = list_entry(plug->rbio_list.next,
struct btrfs_raid_bio, plug_list);
list_del_init(&cur->plug_list);
if (rbio_is_full(cur)) {
int ret;
/* we have a full stripe, send it down */
ret = full_stripe_write(cur);
BUG_ON(ret);
continue;
}
if (last) {
if (rbio_can_merge(last, cur)) {
merge_rbio(last, cur);
__free_raid_bio(cur);
continue;
}
__raid56_parity_write(last);
}
last = cur;
}
if (last) {
__raid56_parity_write(last);
}
kfree(plug);
}
/*
* if the unplug comes from schedule, we have to push the
* work off to a helper thread
*/
static void unplug_work(struct work_struct *work)
{
struct btrfs_plug_cb *plug;
plug = container_of(work, struct btrfs_plug_cb, work);
run_plug(plug);
}
static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
{
struct btrfs_plug_cb *plug;
plug = container_of(cb, struct btrfs_plug_cb, cb);
if (from_schedule) {
INIT_WORK(&plug->work, unplug_work);
queue_work(plug->info->rmw_workers, &plug->work);
return;
}
run_plug(plug);
}
/* Add the original bio into rbio->bio_list, and update rbio::dbitmap. */
static void rbio_add_bio(struct btrfs_raid_bio *rbio, struct bio *orig_bio)
{
const struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
const u64 orig_logical = orig_bio->bi_iter.bi_sector << SECTOR_SHIFT;
const u64 full_stripe_start = rbio->bioc->raid_map[0];
const u32 orig_len = orig_bio->bi_iter.bi_size;
const u32 sectorsize = fs_info->sectorsize;
u64 cur_logical;
ASSERT(orig_logical >= full_stripe_start &&
orig_logical + orig_len <= full_stripe_start +
rbio->nr_data * BTRFS_STRIPE_LEN);
bio_list_add(&rbio->bio_list, orig_bio);
rbio->bio_list_bytes += orig_bio->bi_iter.bi_size;
/* Update the dbitmap. */
for (cur_logical = orig_logical; cur_logical < orig_logical + orig_len;
cur_logical += sectorsize) {
int bit = ((u32)(cur_logical - full_stripe_start) >>
fs_info->sectorsize_bits) % rbio->stripe_nsectors;
set_bit(bit, &rbio->dbitmap);
}
}
/*
* our main entry point for writes from the rest of the FS.
*/
void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
{
struct btrfs_fs_info *fs_info = bioc->fs_info;
struct btrfs_raid_bio *rbio;
struct btrfs_plug_cb *plug = NULL;
struct blk_plug_cb *cb;
int ret = 0;
rbio = alloc_rbio(fs_info, bioc);
if (IS_ERR(rbio)) {
btrfs_put_bioc(bioc);
ret = PTR_ERR(rbio);
goto out_dec_counter;
}
rbio->operation = BTRFS_RBIO_WRITE;
rbio_add_bio(rbio, bio);
rbio->generic_bio_cnt = 1;
/*
* don't plug on full rbios, just get them out the door
* as quickly as we can
*/
if (rbio_is_full(rbio)) {
ret = full_stripe_write(rbio);
if (ret)
goto out_dec_counter;
return;
}
cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug));
if (cb) {
plug = container_of(cb, struct btrfs_plug_cb, cb);
if (!plug->info) {
plug->info = fs_info;
INIT_LIST_HEAD(&plug->rbio_list);
}
list_add_tail(&rbio->plug_list, &plug->rbio_list);
} else {
ret = __raid56_parity_write(rbio);
if (ret)
goto out_dec_counter;
}
return;
out_dec_counter:
btrfs_bio_counter_dec(fs_info);
bio->bi_status = errno_to_blk_status(ret);
bio_endio(bio);
}
/*
* all parity reconstruction happens here. We've read in everything
* we can find from the drives and this does the heavy lifting of
* sorting the good from the bad.
*/
static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
{
const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
int sectornr, stripe;
void **pointers;
void **unmap_array;
int faila = -1, failb = -1;
blk_status_t err;
int i;
/*
* This array stores the pointer for each sector, thus it has the extra
* pgoff value added from each sector
*/
pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
if (!pointers) {
err = BLK_STS_RESOURCE;
goto cleanup_io;
}
/*
* Store copy of pointers that does not get reordered during
* reconstruction so that kunmap_local works.
*/
unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
if (!unmap_array) {
err = BLK_STS_RESOURCE;
goto cleanup_pointers;
}
faila = rbio->faila;
failb = rbio->failb;
if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
spin_lock_irq(&rbio->bio_list_lock);
set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
spin_unlock_irq(&rbio->bio_list_lock);
}
index_rbio_pages(rbio);
for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
struct sector_ptr *sector;
/*
* Now we just use bitmap to mark the horizontal stripes in
* which we have data when doing parity scrub.
*/
if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
!test_bit(sectornr, &rbio->dbitmap))
continue;
/*
* Setup our array of pointers with sectors from each stripe
*
* NOTE: store a duplicate array of pointers to preserve the
* pointer order
*/
for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
/*
* If we're rebuilding a read, we have to use
* pages from the bio list
*/
if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
(stripe == faila || stripe == failb)) {
sector = sector_in_rbio(rbio, stripe, sectornr, 0);
} else {
sector = rbio_stripe_sector(rbio, stripe, sectornr);
}
ASSERT(sector->page);
pointers[stripe] = kmap_local_page(sector->page) +
sector->pgoff;
unmap_array[stripe] = pointers[stripe];
}
/* All raid6 handling here */
if (rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6) {
/* Single failure, rebuild from parity raid5 style */
if (failb < 0) {
if (faila == rbio->nr_data) {
/*
* Just the P stripe has failed, without
* a bad data or Q stripe.
* TODO, we should redo the xor here.
*/
err = BLK_STS_IOERR;
goto cleanup;
}
/*
* a single failure in raid6 is rebuilt
* in the pstripe code below
*/
goto pstripe;
}
/* make sure our ps and qs are in order */
if (faila > failb)
swap(faila, failb);
/* if the q stripe is failed, do a pstripe reconstruction
* from the xors.
* If both the q stripe and the P stripe are failed, we're
* here due to a crc mismatch and we can't give them the
* data they want
*/
if (rbio->bioc->raid_map[failb] == RAID6_Q_STRIPE) {
if (rbio->bioc->raid_map[faila] ==
RAID5_P_STRIPE) {
err = BLK_STS_IOERR;
goto cleanup;
}
/*
* otherwise we have one bad data stripe and
* a good P stripe. raid5!
*/
goto pstripe;
}
if (rbio->bioc->raid_map[failb] == RAID5_P_STRIPE) {
raid6_datap_recov(rbio->real_stripes,
sectorsize, faila, pointers);
} else {
raid6_2data_recov(rbio->real_stripes,
sectorsize, faila, failb,
pointers);
}
} else {
void *p;
/* rebuild from P stripe here (raid5 or raid6) */
BUG_ON(failb != -1);
pstripe:
/* Copy parity block into failed block to start with */
memcpy(pointers[faila], pointers[rbio->nr_data], sectorsize);
/* rearrange the pointer array */
p = pointers[faila];
for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
pointers[stripe] = pointers[stripe + 1];
pointers[rbio->nr_data - 1] = p;
/* xor in the rest */
run_xor(pointers, rbio->nr_data - 1, sectorsize);
}
/* if we're doing this rebuild as part of an rmw, go through
* and set all of our private rbio pages in the
* failed stripes as uptodate. This way finish_rmw will
* know they can be trusted. If this was a read reconstruction,
* other endio functions will fiddle the uptodate bits
*/
if (rbio->operation == BTRFS_RBIO_WRITE) {
for (i = 0; i < rbio->stripe_nsectors; i++) {
if (faila != -1) {
sector = rbio_stripe_sector(rbio, faila, i);
sector->uptodate = 1;
}
if (failb != -1) {
sector = rbio_stripe_sector(rbio, failb, i);
sector->uptodate = 1;
}
}
}
for (stripe = rbio->real_stripes - 1; stripe >= 0; stripe--)
kunmap_local(unmap_array[stripe]);
}
err = BLK_STS_OK;
cleanup:
kfree(unmap_array);
cleanup_pointers:
kfree(pointers);
cleanup_io:
/*
* Similar to READ_REBUILD, REBUILD_MISSING at this point also has a
* valid rbio which is consistent with ondisk content, thus such a
* valid rbio can be cached to avoid further disk reads.
*/
if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
/*
* - In case of two failures, where rbio->failb != -1:
*
* Do not cache this rbio since the above read reconstruction
* (raid6_datap_recov() or raid6_2data_recov()) may have
* changed some content of stripes which are not identical to
* on-disk content any more, otherwise, a later write/recover
* may steal stripe_pages from this rbio and end up with
* corruptions or rebuild failures.
*
* - In case of single failure, where rbio->failb == -1:
*
* Cache this rbio iff the above read reconstruction is
* executed without problems.
*/
if (err == BLK_STS_OK && rbio->failb < 0)
cache_rbio_pages(rbio);
else
clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
rbio_orig_end_io(rbio, err);
} else if (err == BLK_STS_OK) {
rbio->faila = -1;
rbio->failb = -1;
if (rbio->operation == BTRFS_RBIO_WRITE)
finish_rmw(rbio);
else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB)
finish_parity_scrub(rbio, 0);
else
BUG();
} else {
rbio_orig_end_io(rbio, err);
}
}
/*
* This is called only for stripes we've read from disk to reconstruct the
* parity.
*/
static void raid_recover_end_io_work(struct work_struct *work)
{
struct btrfs_raid_bio *rbio =
container_of(work, struct btrfs_raid_bio, end_io_work);
if (atomic_read(&rbio->error) > rbio->bioc->max_errors)
rbio_orig_end_io(rbio, BLK_STS_IOERR);
else
__raid_recover_end_io(rbio);
}
/*
* reads everything we need off the disk to reconstruct
* the parity. endio handlers trigger final reconstruction
* when the IO is done.
*
* This is used both for reads from the higher layers and for
* parity construction required to finish a rmw cycle.
*/
static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
{
int bios_to_read = 0;
struct bio_list bio_list;
int ret;
int total_sector_nr;
struct bio *bio;
bio_list_init(&bio_list);
ret = alloc_rbio_pages(rbio);
if (ret)
goto cleanup;
atomic_set(&rbio->error, 0);
/*
* Read everything that hasn't failed. However this time we will
* not trust any cached sector.
* As we may read out some stale data but higher layer is not reading
* that stale part.
*
* So here we always re-read everything in recovery path.
*/
for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
total_sector_nr++) {
int stripe = total_sector_nr / rbio->stripe_nsectors;
int sectornr = total_sector_nr % rbio->stripe_nsectors;
struct sector_ptr *sector;
if (rbio->faila == stripe || rbio->failb == stripe) {
atomic_inc(&rbio->error);
/* Skip the current stripe. */
ASSERT(sectornr == 0);
total_sector_nr += rbio->stripe_nsectors - 1;
continue;
}
sector = rbio_stripe_sector(rbio, stripe, sectornr);
ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,
sectornr, REQ_OP_READ);
if (ret < 0)
goto cleanup;
}
bios_to_read = bio_list_size(&bio_list);
if (!bios_to_read) {
/*
* we might have no bios to read just because the pages
* were up to date, or we might have no bios to read because
* the devices were gone.
*/
if (atomic_read(&rbio->error) <= rbio->bioc->max_errors) {
__raid_recover_end_io(rbio);
return 0;
} else {
goto cleanup;
}
}
/*
* The bioc may be freed once we submit the last bio. Make sure not to
* touch it after that.
*/
atomic_set(&rbio->stripes_pending, bios_to_read);
INIT_WORK(&rbio->end_io_work, raid_recover_end_io_work);
while ((bio = bio_list_pop(&bio_list))) {
bio->bi_end_io = raid56_bio_end_io;
if (trace_raid56_scrub_read_recover_enabled()) {
struct raid56_bio_trace_info trace_info = { 0 };
bio_get_trace_info(rbio, bio, &trace_info);
trace_raid56_scrub_read_recover(rbio, bio, &trace_info);
}
submit_bio(bio);
}
return 0;
cleanup:
if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
rbio->operation == BTRFS_RBIO_REBUILD_MISSING)
rbio_orig_end_io(rbio, BLK_STS_IOERR);
while ((bio = bio_list_pop(&bio_list)))
bio_put(bio);
return -EIO;
}
/*
* the main entry point for reads from the higher layers. This
* is really only called when the normal read path had a failure,
* so we assume the bio they send down corresponds to a failed part
* of the drive.
*/
void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
int mirror_num, bool generic_io)
{
struct btrfs_fs_info *fs_info = bioc->fs_info;
struct btrfs_raid_bio *rbio;
if (generic_io) {
ASSERT(bioc->mirror_num == mirror_num);
btrfs_bio(bio)->mirror_num = mirror_num;
} else {
btrfs_get_bioc(bioc);
}
rbio = alloc_rbio(fs_info, bioc);
if (IS_ERR(rbio)) {
bio->bi_status = errno_to_blk_status(PTR_ERR(rbio));
goto out_end_bio;
}
rbio->operation = BTRFS_RBIO_READ_REBUILD;
rbio_add_bio(rbio, bio);
rbio->faila = find_logical_bio_stripe(rbio, bio);
if (rbio->faila == -1) {
btrfs_warn(fs_info,
"%s could not find the bad stripe in raid56 so that we cannot recover any more (bio has logical %llu len %llu, bioc has map_type %llu)",
__func__, bio->bi_iter.bi_sector << 9,
(u64)bio->bi_iter.bi_size, bioc->map_type);
kfree(rbio);
bio->bi_status = BLK_STS_IOERR;
goto out_end_bio;
}
if (generic_io)
rbio->generic_bio_cnt = 1;
/*
* Loop retry:
* for 'mirror == 2', reconstruct from all other stripes.
* for 'mirror_num > 2', select a stripe to fail on every retry.
*/
if (mirror_num > 2) {
/*
* 'mirror == 3' is to fail the p stripe and
* reconstruct from the q stripe. 'mirror > 3' is to
* fail a data stripe and reconstruct from p+q stripe.
*/
rbio->failb = rbio->real_stripes - (mirror_num - 1);
ASSERT(rbio->failb > 0);
if (rbio->failb <= rbio->faila)
rbio->failb--;
}
if (lock_stripe_add(rbio))
return;
/*
* This adds our rbio to the list of rbios that will be handled after
* the current lock owner is done.
*/
__raid56_parity_recover(rbio);
return;
out_end_bio:
btrfs_bio_counter_dec(fs_info);
btrfs_put_bioc(bioc);
bio_endio(bio);
}
static void rmw_work(struct work_struct *work)
{
struct btrfs_raid_bio *rbio;
rbio = container_of(work, struct btrfs_raid_bio, work);
raid56_rmw_stripe(rbio);
}
static void read_rebuild_work(struct work_struct *work)
{
struct btrfs_raid_bio *rbio;
rbio = container_of(work, struct btrfs_raid_bio, work);
__raid56_parity_recover(rbio);
}
/*
* The following code is used to scrub/replace the parity stripe
*
* Caller must have already increased bio_counter for getting @bioc.
*
* Note: We need make sure all the pages that add into the scrub/replace
* raid bio are correct and not be changed during the scrub/replace. That
* is those pages just hold metadata or file data with checksum.
*/
struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
struct btrfs_io_context *bioc,
struct btrfs_device *scrub_dev,
unsigned long *dbitmap, int stripe_nsectors)
{
struct btrfs_fs_info *fs_info = bioc->fs_info;
struct btrfs_raid_bio *rbio;
int i;
rbio = alloc_rbio(fs_info, bioc);
if (IS_ERR(rbio))
return NULL;
bio_list_add(&rbio->bio_list, bio);
/*
* This is a special bio which is used to hold the completion handler
* and make the scrub rbio is similar to the other types
*/
ASSERT(!bio->bi_iter.bi_size);
rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
/*
* After mapping bioc with BTRFS_MAP_WRITE, parities have been sorted
* to the end position, so this search can start from the first parity
* stripe.
*/
for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
if (bioc->stripes[i].dev == scrub_dev) {
rbio->scrubp = i;
break;
}
}
ASSERT(i < rbio->real_stripes);
bitmap_copy(&rbio->dbitmap, dbitmap, stripe_nsectors);
/*
* We have already increased bio_counter when getting bioc, record it
* so we can free it at rbio_orig_end_io().
*/
rbio->generic_bio_cnt = 1;
return rbio;
}
/* Used for both parity scrub and missing. */
void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
unsigned int pgoff, u64 logical)
{
const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
int stripe_offset;
int index;
ASSERT(logical >= rbio->bioc->raid_map[0]);
ASSERT(logical + sectorsize <= rbio->bioc->raid_map[0] +
BTRFS_STRIPE_LEN * rbio->nr_data);
stripe_offset = (int)(logical - rbio->bioc->raid_map[0]);
index = stripe_offset / sectorsize;
rbio->bio_sectors[index].page = page;
rbio->bio_sectors[index].pgoff = pgoff;
}
/*
* We just scrub the parity that we have correct data on the same horizontal,
* so we needn't allocate all pages for all the stripes.
*/
static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
{
const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
int total_sector_nr;
for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
total_sector_nr++) {
struct page *page;
int sectornr = total_sector_nr % rbio->stripe_nsectors;
int index = (total_sector_nr * sectorsize) >> PAGE_SHIFT;
if (!test_bit(sectornr, &rbio->dbitmap))
continue;
if (rbio->stripe_pages[index])
continue;
page = alloc_page(GFP_NOFS);
if (!page)
return -ENOMEM;
rbio->stripe_pages[index] = page;
}
index_stripe_sectors(rbio);
return 0;
}
static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
int need_check)
{
struct btrfs_io_context *bioc = rbio->bioc;
const u32 sectorsize = bioc->fs_info->sectorsize;
void **pointers = rbio->finish_pointers;
unsigned long *pbitmap = &rbio->finish_pbitmap;
int nr_data = rbio->nr_data;
int stripe;
int sectornr;
bool has_qstripe;
struct sector_ptr p_sector = { 0 };
struct sector_ptr q_sector = { 0 };
struct bio_list bio_list;
struct bio *bio;
int is_replace = 0;
int ret;
bio_list_init(&bio_list);
if (rbio->real_stripes - rbio->nr_data == 1)
has_qstripe = false;
else if (rbio->real_stripes - rbio->nr_data == 2)
has_qstripe = true;
else
BUG();
if (bioc->num_tgtdevs && bioc->tgtdev_map[rbio->scrubp]) {
is_replace = 1;
bitmap_copy(pbitmap, &rbio->dbitmap, rbio->stripe_nsectors);
}
/*
* Because the higher layers(scrubber) are unlikely to
* use this area of the disk again soon, so don't cache
* it.
*/
clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
if (!need_check)
goto writeback;
p_sector.page = alloc_page(GFP_NOFS);
if (!p_sector.page)
goto cleanup;
p_sector.pgoff = 0;
p_sector.uptodate = 1;
if (has_qstripe) {
/* RAID6, allocate and map temp space for the Q stripe */
q_sector.page = alloc_page(GFP_NOFS);
if (!q_sector.page) {
__free_page(p_sector.page);
p_sector.page = NULL;
goto cleanup;
}
q_sector.pgoff = 0;
q_sector.uptodate = 1;
pointers[rbio->real_stripes - 1] = kmap_local_page(q_sector.page);
}
atomic_set(&rbio->error, 0);
/* Map the parity stripe just once */
pointers[nr_data] = kmap_local_page(p_sector.page);
for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {
struct sector_ptr *sector;
void *parity;
/* first collect one page from each data stripe */
for (stripe = 0; stripe < nr_data; stripe++) {
sector = sector_in_rbio(rbio, stripe, sectornr, 0);
pointers[stripe] = kmap_local_page(sector->page) +
sector->pgoff;
}
if (has_qstripe) {
/* RAID6, call the library function to fill in our P/Q */
raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,
pointers);
} else {
/* raid5 */
memcpy(pointers[nr_data], pointers[0], sectorsize);
run_xor(pointers + 1, nr_data - 1, sectorsize);
}
/* Check scrubbing parity and repair it */
sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
parity = kmap_local_page(sector->page) + sector->pgoff;
if (memcmp(parity, pointers[rbio->scrubp], sectorsize) != 0)
memcpy(parity, pointers[rbio->scrubp], sectorsize);
else
/* Parity is right, needn't writeback */
bitmap_clear(&rbio->dbitmap, sectornr, 1);
kunmap_local(parity);
for (stripe = nr_data - 1; stripe >= 0; stripe--)
kunmap_local(pointers[stripe]);
}
kunmap_local(pointers[nr_data]);
__free_page(p_sector.page);
p_sector.page = NULL;
if (q_sector.page) {
kunmap_local(pointers[rbio->real_stripes - 1]);
__free_page(q_sector.page);
q_sector.page = NULL;
}
writeback:
/*
* time to start writing. Make bios for everything from the
* higher layers (the bio_list in our rbio) and our p/q. Ignore
* everything else.
*/
for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {
struct sector_ptr *sector;
sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
ret = rbio_add_io_sector(rbio, &bio_list, sector, rbio->scrubp,
sectornr, REQ_OP_WRITE);
if (ret)
goto cleanup;
}
if (!is_replace)
goto submit_write;
for_each_set_bit(sectornr, pbitmap, rbio->stripe_nsectors) {
struct sector_ptr *sector;
sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
ret = rbio_add_io_sector(rbio, &bio_list, sector,
bioc->tgtdev_map[rbio->scrubp],
sectornr, REQ_OP_WRITE);
if (ret)
goto cleanup;
}
submit_write:
nr_data = bio_list_size(&bio_list);
if (!nr_data) {
/* Every parity is right */
rbio_orig_end_io(rbio, BLK_STS_OK);
return;
}
atomic_set(&rbio->stripes_pending, nr_data);
while ((bio = bio_list_pop(&bio_list))) {
bio->bi_end_io = raid_write_end_io;
if (trace_raid56_scrub_write_stripe_enabled()) {
struct raid56_bio_trace_info trace_info = { 0 };
bio_get_trace_info(rbio, bio, &trace_info);
trace_raid56_scrub_write_stripe(rbio, bio, &trace_info);
}
submit_bio(bio);
}
return;
cleanup:
rbio_orig_end_io(rbio, BLK_STS_IOERR);
while ((bio = bio_list_pop(&bio_list)))
bio_put(bio);
}
static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
{
if (stripe >= 0 && stripe < rbio->nr_data)
return 1;
return 0;
}
/*
* While we're doing the parity check and repair, we could have errors
* in reading pages off the disk. This checks for errors and if we're
* not able to read the page it'll trigger parity reconstruction. The
* parity scrub will be finished after we've reconstructed the failed
* stripes
*/
static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio)
{
if (atomic_read(&rbio->error) > rbio->bioc->max_errors)
goto cleanup;
if (rbio->faila >= 0 || rbio->failb >= 0) {
int dfail = 0, failp = -1;
if (is_data_stripe(rbio, rbio->faila))
dfail++;
else if (is_parity_stripe(rbio->faila))
failp = rbio->faila;
if (is_data_stripe(rbio, rbio->failb))
dfail++;
else if (is_parity_stripe(rbio->failb))
failp = rbio->failb;
/*
* Because we can not use a scrubbing parity to repair
* the data, so the capability of the repair is declined.
* (In the case of RAID5, we can not repair anything)
*/
if (dfail > rbio->bioc->max_errors - 1)
goto cleanup;
/*
* If all data is good, only parity is correctly, just
* repair the parity.
*/
if (dfail == 0) {
finish_parity_scrub(rbio, 0);
return;
}
/*
* Here means we got one corrupted data stripe and one
* corrupted parity on RAID6, if the corrupted parity
* is scrubbing parity, luckily, use the other one to repair
* the data, or we can not repair the data stripe.
*/
if (failp != rbio->scrubp)
goto cleanup;
__raid_recover_end_io(rbio);
} else {
finish_parity_scrub(rbio, 1);
}
return;
cleanup:
rbio_orig_end_io(rbio, BLK_STS_IOERR);
}
/*
* end io for the read phase of the rmw cycle. All the bios here are physical
* stripe bios we've read from the disk so we can recalculate the parity of the
* stripe.
*
* This will usually kick off finish_rmw once all the bios are read in, but it
* may trigger parity reconstruction if we had any errors along the way
*/
static void raid56_parity_scrub_end_io_work(struct work_struct *work)
{
struct btrfs_raid_bio *rbio =
container_of(work, struct btrfs_raid_bio, end_io_work);
/*
* This will normally call finish_rmw to start our write, but if there
* are any failed stripes we'll reconstruct from parity first
*/
validate_rbio_for_parity_scrub(rbio);
}
static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
{
int bios_to_read = 0;
struct bio_list bio_list;
int ret;
int total_sector_nr;
struct bio *bio;
bio_list_init(&bio_list);
ret = alloc_rbio_essential_pages(rbio);
if (ret)
goto cleanup;
atomic_set(&rbio->error, 0);
/* Build a list of bios to read all the missing parts. */
for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
total_sector_nr++) {
int sectornr = total_sector_nr % rbio->stripe_nsectors;
int stripe = total_sector_nr / rbio->stripe_nsectors;
struct sector_ptr *sector;
/* No data in the vertical stripe, no need to read. */
if (!test_bit(sectornr, &rbio->dbitmap))
continue;
/*
* We want to find all the sectors missing from the rbio and
* read them from the disk. If sector_in_rbio() finds a sector
* in the bio list we don't need to read it off the stripe.
*/
sector = sector_in_rbio(rbio, stripe, sectornr, 1);
if (sector)
continue;
sector = rbio_stripe_sector(rbio, stripe, sectornr);
/*
* The bio cache may have handed us an uptodate sector. If so,
* use it.
*/
if (sector->uptodate)
continue;
ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,
sectornr, REQ_OP_READ);
if (ret)
goto cleanup;
}
bios_to_read = bio_list_size(&bio_list);
if (!bios_to_read) {
/*
* this can happen if others have merged with
* us, it means there is nothing left to read.
* But if there are missing devices it may not be
* safe to do the full stripe write yet.
*/
goto finish;
}
/*
* The bioc may be freed once we submit the last bio. Make sure not to
* touch it after that.
*/
atomic_set(&rbio->stripes_pending, bios_to_read);
INIT_WORK(&rbio->end_io_work, raid56_parity_scrub_end_io_work);
while ((bio = bio_list_pop(&bio_list))) {
bio->bi_end_io = raid56_bio_end_io;
if (trace_raid56_scrub_read_enabled()) {
struct raid56_bio_trace_info trace_info = { 0 };
bio_get_trace_info(rbio, bio, &trace_info);
trace_raid56_scrub_read(rbio, bio, &trace_info);
}
submit_bio(bio);
}
/* the actual write will happen once the reads are done */
return;
cleanup:
rbio_orig_end_io(rbio, BLK_STS_IOERR);
while ((bio = bio_list_pop(&bio_list)))
bio_put(bio);
return;
finish:
validate_rbio_for_parity_scrub(rbio);
}
static void scrub_parity_work(struct work_struct *work)
{
struct btrfs_raid_bio *rbio;
rbio = container_of(work, struct btrfs_raid_bio, work);
raid56_parity_scrub_stripe(rbio);
}
void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
{
if (!lock_stripe_add(rbio))
start_async_work(rbio, scrub_parity_work);
}
/* The following code is used for dev replace of a missing RAID 5/6 device. */
struct btrfs_raid_bio *
raid56_alloc_missing_rbio(struct bio *bio, struct btrfs_io_context *bioc)
{
struct btrfs_fs_info *fs_info = bioc->fs_info;
struct btrfs_raid_bio *rbio;
rbio = alloc_rbio(fs_info, bioc);
if (IS_ERR(rbio))
return NULL;
rbio->operation = BTRFS_RBIO_REBUILD_MISSING;
bio_list_add(&rbio->bio_list, bio);
/*
* This is a special bio which is used to hold the completion handler
* and make the scrub rbio is similar to the other types
*/
ASSERT(!bio->bi_iter.bi_size);
rbio->faila = find_logical_bio_stripe(rbio, bio);
if (rbio->faila == -1) {
BUG();
kfree(rbio);
return NULL;
}
/*
* When we get bioc, we have already increased bio_counter, record it
* so we can free it at rbio_orig_end_io()
*/
rbio->generic_bio_cnt = 1;
return rbio;
}
void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
{
if (!lock_stripe_add(rbio))
start_async_work(rbio, read_rebuild_work);
}