linux/drivers/md/bcache/bcache.h
Kent Overstreet 749b61dab3 bcache: remove driver private bio splitting code
The bcache driver has always accepted arbitrarily large bios and split
them internally.  Now that every driver must accept arbitrarily large
bios this code isn't nessecary anymore.

Cc: linux-bcache@vger.kernel.org
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-13 12:31:40 -06:00

929 lines
28 KiB
C

#ifndef _BCACHE_H
#define _BCACHE_H
/*
* SOME HIGH LEVEL CODE DOCUMENTATION:
*
* Bcache mostly works with cache sets, cache devices, and backing devices.
*
* Support for multiple cache devices hasn't quite been finished off yet, but
* it's about 95% plumbed through. A cache set and its cache devices is sort of
* like a md raid array and its component devices. Most of the code doesn't care
* about individual cache devices, the main abstraction is the cache set.
*
* Multiple cache devices is intended to give us the ability to mirror dirty
* cached data and metadata, without mirroring clean cached data.
*
* Backing devices are different, in that they have a lifetime independent of a
* cache set. When you register a newly formatted backing device it'll come up
* in passthrough mode, and then you can attach and detach a backing device from
* a cache set at runtime - while it's mounted and in use. Detaching implicitly
* invalidates any cached data for that backing device.
*
* A cache set can have multiple (many) backing devices attached to it.
*
* There's also flash only volumes - this is the reason for the distinction
* between struct cached_dev and struct bcache_device. A flash only volume
* works much like a bcache device that has a backing device, except the
* "cached" data is always dirty. The end result is that we get thin
* provisioning with very little additional code.
*
* Flash only volumes work but they're not production ready because the moving
* garbage collector needs more work. More on that later.
*
* BUCKETS/ALLOCATION:
*
* Bcache is primarily designed for caching, which means that in normal
* operation all of our available space will be allocated. Thus, we need an
* efficient way of deleting things from the cache so we can write new things to
* it.
*
* To do this, we first divide the cache device up into buckets. A bucket is the
* unit of allocation; they're typically around 1 mb - anywhere from 128k to 2M+
* works efficiently.
*
* Each bucket has a 16 bit priority, and an 8 bit generation associated with
* it. The gens and priorities for all the buckets are stored contiguously and
* packed on disk (in a linked list of buckets - aside from the superblock, all
* of bcache's metadata is stored in buckets).
*
* The priority is used to implement an LRU. We reset a bucket's priority when
* we allocate it or on cache it, and every so often we decrement the priority
* of each bucket. It could be used to implement something more sophisticated,
* if anyone ever gets around to it.
*
* The generation is used for invalidating buckets. Each pointer also has an 8
* bit generation embedded in it; for a pointer to be considered valid, its gen
* must match the gen of the bucket it points into. Thus, to reuse a bucket all
* we have to do is increment its gen (and write its new gen to disk; we batch
* this up).
*
* Bcache is entirely COW - we never write twice to a bucket, even buckets that
* contain metadata (including btree nodes).
*
* THE BTREE:
*
* Bcache is in large part design around the btree.
*
* At a high level, the btree is just an index of key -> ptr tuples.
*
* Keys represent extents, and thus have a size field. Keys also have a variable
* number of pointers attached to them (potentially zero, which is handy for
* invalidating the cache).
*
* The key itself is an inode:offset pair. The inode number corresponds to a
* backing device or a flash only volume. The offset is the ending offset of the
* extent within the inode - not the starting offset; this makes lookups
* slightly more convenient.
*
* Pointers contain the cache device id, the offset on that device, and an 8 bit
* generation number. More on the gen later.
*
* Index lookups are not fully abstracted - cache lookups in particular are
* still somewhat mixed in with the btree code, but things are headed in that
* direction.
*
* Updates are fairly well abstracted, though. There are two different ways of
* updating the btree; insert and replace.
*
* BTREE_INSERT will just take a list of keys and insert them into the btree -
* overwriting (possibly only partially) any extents they overlap with. This is
* used to update the index after a write.
*
* BTREE_REPLACE is really cmpxchg(); it inserts a key into the btree iff it is
* overwriting a key that matches another given key. This is used for inserting
* data into the cache after a cache miss, and for background writeback, and for
* the moving garbage collector.
*
* There is no "delete" operation; deleting things from the index is
* accomplished by either by invalidating pointers (by incrementing a bucket's
* gen) or by inserting a key with 0 pointers - which will overwrite anything
* previously present at that location in the index.
*
* This means that there are always stale/invalid keys in the btree. They're
* filtered out by the code that iterates through a btree node, and removed when
* a btree node is rewritten.
*
* BTREE NODES:
*
* Our unit of allocation is a bucket, and we we can't arbitrarily allocate and
* free smaller than a bucket - so, that's how big our btree nodes are.
*
* (If buckets are really big we'll only use part of the bucket for a btree node
* - no less than 1/4th - but a bucket still contains no more than a single
* btree node. I'd actually like to change this, but for now we rely on the
* bucket's gen for deleting btree nodes when we rewrite/split a node.)
*
* Anyways, btree nodes are big - big enough to be inefficient with a textbook
* btree implementation.
*
* The way this is solved is that btree nodes are internally log structured; we
* can append new keys to an existing btree node without rewriting it. This
* means each set of keys we write is sorted, but the node is not.
*
* We maintain this log structure in memory - keeping 1Mb of keys sorted would
* be expensive, and we have to distinguish between the keys we have written and
* the keys we haven't. So to do a lookup in a btree node, we have to search
* each sorted set. But we do merge written sets together lazily, so the cost of
* these extra searches is quite low (normally most of the keys in a btree node
* will be in one big set, and then there'll be one or two sets that are much
* smaller).
*
* This log structure makes bcache's btree more of a hybrid between a
* conventional btree and a compacting data structure, with some of the
* advantages of both.
*
* GARBAGE COLLECTION:
*
* We can't just invalidate any bucket - it might contain dirty data or
* metadata. If it once contained dirty data, other writes might overwrite it
* later, leaving no valid pointers into that bucket in the index.
*
* Thus, the primary purpose of garbage collection is to find buckets to reuse.
* It also counts how much valid data it each bucket currently contains, so that
* allocation can reuse buckets sooner when they've been mostly overwritten.
*
* It also does some things that are really internal to the btree
* implementation. If a btree node contains pointers that are stale by more than
* some threshold, it rewrites the btree node to avoid the bucket's generation
* wrapping around. It also merges adjacent btree nodes if they're empty enough.
*
* THE JOURNAL:
*
* Bcache's journal is not necessary for consistency; we always strictly
* order metadata writes so that the btree and everything else is consistent on
* disk in the event of an unclean shutdown, and in fact bcache had writeback
* caching (with recovery from unclean shutdown) before journalling was
* implemented.
*
* Rather, the journal is purely a performance optimization; we can't complete a
* write until we've updated the index on disk, otherwise the cache would be
* inconsistent in the event of an unclean shutdown. This means that without the
* journal, on random write workloads we constantly have to update all the leaf
* nodes in the btree, and those writes will be mostly empty (appending at most
* a few keys each) - highly inefficient in terms of amount of metadata writes,
* and it puts more strain on the various btree resorting/compacting code.
*
* The journal is just a log of keys we've inserted; on startup we just reinsert
* all the keys in the open journal entries. That means that when we're updating
* a node in the btree, we can wait until a 4k block of keys fills up before
* writing them out.
*
* For simplicity, we only journal updates to leaf nodes; updates to parent
* nodes are rare enough (since our leaf nodes are huge) that it wasn't worth
* the complexity to deal with journalling them (in particular, journal replay)
* - updates to non leaf nodes just happen synchronously (see btree_split()).
*/
#define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__
#include <linux/bcache.h>
#include <linux/bio.h>
#include <linux/kobject.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/rbtree.h>
#include <linux/rwsem.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include "bset.h"
#include "util.h"
#include "closure.h"
struct bucket {
atomic_t pin;
uint16_t prio;
uint8_t gen;
uint8_t last_gc; /* Most out of date gen in the btree */
uint16_t gc_mark; /* Bitfield used by GC. See below for field */
};
/*
* I'd use bitfields for these, but I don't trust the compiler not to screw me
* as multiple threads touch struct bucket without locking
*/
BITMASK(GC_MARK, struct bucket, gc_mark, 0, 2);
#define GC_MARK_RECLAIMABLE 1
#define GC_MARK_DIRTY 2
#define GC_MARK_METADATA 3
#define GC_SECTORS_USED_SIZE 13
#define MAX_GC_SECTORS_USED (~(~0ULL << GC_SECTORS_USED_SIZE))
BITMASK(GC_SECTORS_USED, struct bucket, gc_mark, 2, GC_SECTORS_USED_SIZE);
BITMASK(GC_MOVE, struct bucket, gc_mark, 15, 1);
#include "journal.h"
#include "stats.h"
struct search;
struct btree;
struct keybuf;
struct keybuf_key {
struct rb_node node;
BKEY_PADDED(key);
void *private;
};
struct keybuf {
struct bkey last_scanned;
spinlock_t lock;
/*
* Beginning and end of range in rb tree - so that we can skip taking
* lock and checking the rb tree when we need to check for overlapping
* keys.
*/
struct bkey start;
struct bkey end;
struct rb_root keys;
#define KEYBUF_NR 500
DECLARE_ARRAY_ALLOCATOR(struct keybuf_key, freelist, KEYBUF_NR);
};
struct bcache_device {
struct closure cl;
struct kobject kobj;
struct cache_set *c;
unsigned id;
#define BCACHEDEVNAME_SIZE 12
char name[BCACHEDEVNAME_SIZE];
struct gendisk *disk;
unsigned long flags;
#define BCACHE_DEV_CLOSING 0
#define BCACHE_DEV_DETACHING 1
#define BCACHE_DEV_UNLINK_DONE 2
unsigned nr_stripes;
unsigned stripe_size;
atomic_t *stripe_sectors_dirty;
unsigned long *full_dirty_stripes;
unsigned long sectors_dirty_last;
long sectors_dirty_derivative;
struct bio_set *bio_split;
unsigned data_csum:1;
int (*cache_miss)(struct btree *, struct search *,
struct bio *, unsigned);
int (*ioctl) (struct bcache_device *, fmode_t, unsigned, unsigned long);
};
struct io {
/* Used to track sequential IO so it can be skipped */
struct hlist_node hash;
struct list_head lru;
unsigned long jiffies;
unsigned sequential;
sector_t last;
};
struct cached_dev {
struct list_head list;
struct bcache_device disk;
struct block_device *bdev;
struct cache_sb sb;
struct bio sb_bio;
struct bio_vec sb_bv[1];
struct closure sb_write;
struct semaphore sb_write_mutex;
/* Refcount on the cache set. Always nonzero when we're caching. */
atomic_t count;
struct work_struct detach;
/*
* Device might not be running if it's dirty and the cache set hasn't
* showed up yet.
*/
atomic_t running;
/*
* Writes take a shared lock from start to finish; scanning for dirty
* data to refill the rb tree requires an exclusive lock.
*/
struct rw_semaphore writeback_lock;
/*
* Nonzero, and writeback has a refcount (d->count), iff there is dirty
* data in the cache. Protected by writeback_lock; must have an
* shared lock to set and exclusive lock to clear.
*/
atomic_t has_dirty;
struct bch_ratelimit writeback_rate;
struct delayed_work writeback_rate_update;
/*
* Internal to the writeback code, so read_dirty() can keep track of
* where it's at.
*/
sector_t last_read;
/* Limit number of writeback bios in flight */
struct semaphore in_flight;
struct task_struct *writeback_thread;
struct keybuf writeback_keys;
/* For tracking sequential IO */
#define RECENT_IO_BITS 7
#define RECENT_IO (1 << RECENT_IO_BITS)
struct io io[RECENT_IO];
struct hlist_head io_hash[RECENT_IO + 1];
struct list_head io_lru;
spinlock_t io_lock;
struct cache_accounting accounting;
/* The rest of this all shows up in sysfs */
unsigned sequential_cutoff;
unsigned readahead;
unsigned verify:1;
unsigned bypass_torture_test:1;
unsigned partial_stripes_expensive:1;
unsigned writeback_metadata:1;
unsigned writeback_running:1;
unsigned char writeback_percent;
unsigned writeback_delay;
uint64_t writeback_rate_target;
int64_t writeback_rate_proportional;
int64_t writeback_rate_derivative;
int64_t writeback_rate_change;
unsigned writeback_rate_update_seconds;
unsigned writeback_rate_d_term;
unsigned writeback_rate_p_term_inverse;
};
enum alloc_reserve {
RESERVE_BTREE,
RESERVE_PRIO,
RESERVE_MOVINGGC,
RESERVE_NONE,
RESERVE_NR,
};
struct cache {
struct cache_set *set;
struct cache_sb sb;
struct bio sb_bio;
struct bio_vec sb_bv[1];
struct kobject kobj;
struct block_device *bdev;
struct task_struct *alloc_thread;
struct closure prio;
struct prio_set *disk_buckets;
/*
* When allocating new buckets, prio_write() gets first dibs - since we
* may not be allocate at all without writing priorities and gens.
* prio_buckets[] contains the last buckets we wrote priorities to (so
* gc can mark them as metadata), prio_next[] contains the buckets
* allocated for the next prio write.
*/
uint64_t *prio_buckets;
uint64_t *prio_last_buckets;
/*
* free: Buckets that are ready to be used
*
* free_inc: Incoming buckets - these are buckets that currently have
* cached data in them, and we can't reuse them until after we write
* their new gen to disk. After prio_write() finishes writing the new
* gens/prios, they'll be moved to the free list (and possibly discarded
* in the process)
*/
DECLARE_FIFO(long, free)[RESERVE_NR];
DECLARE_FIFO(long, free_inc);
size_t fifo_last_bucket;
/* Allocation stuff: */
struct bucket *buckets;
DECLARE_HEAP(struct bucket *, heap);
/*
* If nonzero, we know we aren't going to find any buckets to invalidate
* until a gc finishes - otherwise we could pointlessly burn a ton of
* cpu
*/
unsigned invalidate_needs_gc:1;
bool discard; /* Get rid of? */
struct journal_device journal;
/* The rest of this all shows up in sysfs */
#define IO_ERROR_SHIFT 20
atomic_t io_errors;
atomic_t io_count;
atomic_long_t meta_sectors_written;
atomic_long_t btree_sectors_written;
atomic_long_t sectors_written;
};
struct gc_stat {
size_t nodes;
size_t key_bytes;
size_t nkeys;
uint64_t data; /* sectors */
unsigned in_use; /* percent */
};
/*
* Flag bits, for how the cache set is shutting down, and what phase it's at:
*
* CACHE_SET_UNREGISTERING means we're not just shutting down, we're detaching
* all the backing devices first (their cached data gets invalidated, and they
* won't automatically reattach).
*
* CACHE_SET_STOPPING always gets set first when we're closing down a cache set;
* we'll continue to run normally for awhile with CACHE_SET_STOPPING set (i.e.
* flushing dirty data).
*
* CACHE_SET_RUNNING means all cache devices have been registered and journal
* replay is complete.
*/
#define CACHE_SET_UNREGISTERING 0
#define CACHE_SET_STOPPING 1
#define CACHE_SET_RUNNING 2
struct cache_set {
struct closure cl;
struct list_head list;
struct kobject kobj;
struct kobject internal;
struct dentry *debug;
struct cache_accounting accounting;
unsigned long flags;
struct cache_sb sb;
struct cache *cache[MAX_CACHES_PER_SET];
struct cache *cache_by_alloc[MAX_CACHES_PER_SET];
int caches_loaded;
struct bcache_device **devices;
struct list_head cached_devs;
uint64_t cached_dev_sectors;
struct closure caching;
struct closure sb_write;
struct semaphore sb_write_mutex;
mempool_t *search;
mempool_t *bio_meta;
struct bio_set *bio_split;
/* For the btree cache */
struct shrinker shrink;
/* For the btree cache and anything allocation related */
struct mutex bucket_lock;
/* log2(bucket_size), in sectors */
unsigned short bucket_bits;
/* log2(block_size), in sectors */
unsigned short block_bits;
/*
* Default number of pages for a new btree node - may be less than a
* full bucket
*/
unsigned btree_pages;
/*
* Lists of struct btrees; lru is the list for structs that have memory
* allocated for actual btree node, freed is for structs that do not.
*
* We never free a struct btree, except on shutdown - we just put it on
* the btree_cache_freed list and reuse it later. This simplifies the
* code, and it doesn't cost us much memory as the memory usage is
* dominated by buffers that hold the actual btree node data and those
* can be freed - and the number of struct btrees allocated is
* effectively bounded.
*
* btree_cache_freeable effectively is a small cache - we use it because
* high order page allocations can be rather expensive, and it's quite
* common to delete and allocate btree nodes in quick succession. It
* should never grow past ~2-3 nodes in practice.
*/
struct list_head btree_cache;
struct list_head btree_cache_freeable;
struct list_head btree_cache_freed;
/* Number of elements in btree_cache + btree_cache_freeable lists */
unsigned btree_cache_used;
/*
* If we need to allocate memory for a new btree node and that
* allocation fails, we can cannibalize another node in the btree cache
* to satisfy the allocation - lock to guarantee only one thread does
* this at a time:
*/
wait_queue_head_t btree_cache_wait;
struct task_struct *btree_cache_alloc_lock;
/*
* When we free a btree node, we increment the gen of the bucket the
* node is in - but we can't rewrite the prios and gens until we
* finished whatever it is we were doing, otherwise after a crash the
* btree node would be freed but for say a split, we might not have the
* pointers to the new nodes inserted into the btree yet.
*
* This is a refcount that blocks prio_write() until the new keys are
* written.
*/
atomic_t prio_blocked;
wait_queue_head_t bucket_wait;
/*
* For any bio we don't skip we subtract the number of sectors from
* rescale; when it hits 0 we rescale all the bucket priorities.
*/
atomic_t rescale;
/*
* When we invalidate buckets, we use both the priority and the amount
* of good data to determine which buckets to reuse first - to weight
* those together consistently we keep track of the smallest nonzero
* priority of any bucket.
*/
uint16_t min_prio;
/*
* max(gen - last_gc) for all buckets. When it gets too big we have to gc
* to keep gens from wrapping around.
*/
uint8_t need_gc;
struct gc_stat gc_stats;
size_t nbuckets;
struct task_struct *gc_thread;
/* Where in the btree gc currently is */
struct bkey gc_done;
/*
* The allocation code needs gc_mark in struct bucket to be correct, but
* it's not while a gc is in progress. Protected by bucket_lock.
*/
int gc_mark_valid;
/* Counts how many sectors bio_insert has added to the cache */
atomic_t sectors_to_gc;
wait_queue_head_t moving_gc_wait;
struct keybuf moving_gc_keys;
/* Number of moving GC bios in flight */
struct semaphore moving_in_flight;
struct workqueue_struct *moving_gc_wq;
struct btree *root;
#ifdef CONFIG_BCACHE_DEBUG
struct btree *verify_data;
struct bset *verify_ondisk;
struct mutex verify_lock;
#endif
unsigned nr_uuids;
struct uuid_entry *uuids;
BKEY_PADDED(uuid_bucket);
struct closure uuid_write;
struct semaphore uuid_write_mutex;
/*
* A btree node on disk could have too many bsets for an iterator to fit
* on the stack - have to dynamically allocate them
*/
mempool_t *fill_iter;
struct bset_sort_state sort;
/* List of buckets we're currently writing data to */
struct list_head data_buckets;
spinlock_t data_bucket_lock;
struct journal journal;
#define CONGESTED_MAX 1024
unsigned congested_last_us;
atomic_t congested;
/* The rest of this all shows up in sysfs */
unsigned congested_read_threshold_us;
unsigned congested_write_threshold_us;
struct time_stats btree_gc_time;
struct time_stats btree_split_time;
struct time_stats btree_read_time;
atomic_long_t cache_read_races;
atomic_long_t writeback_keys_done;
atomic_long_t writeback_keys_failed;
enum {
ON_ERROR_UNREGISTER,
ON_ERROR_PANIC,
} on_error;
unsigned error_limit;
unsigned error_decay;
unsigned short journal_delay_ms;
bool expensive_debug_checks;
unsigned verify:1;
unsigned key_merging_disabled:1;
unsigned gc_always_rewrite:1;
unsigned shrinker_disabled:1;
unsigned copy_gc_enabled:1;
#define BUCKET_HASH_BITS 12
struct hlist_head bucket_hash[1 << BUCKET_HASH_BITS];
};
struct bbio {
unsigned submit_time_us;
union {
struct bkey key;
uint64_t _pad[3];
/*
* We only need pad = 3 here because we only ever carry around a
* single pointer - i.e. the pointer we're doing io to/from.
*/
};
struct bio bio;
};
#define BTREE_PRIO USHRT_MAX
#define INITIAL_PRIO 32768U
#define btree_bytes(c) ((c)->btree_pages * PAGE_SIZE)
#define btree_blocks(b) \
((unsigned) (KEY_SIZE(&b->key) >> (b)->c->block_bits))
#define btree_default_blocks(c) \
((unsigned) ((PAGE_SECTORS * (c)->btree_pages) >> (c)->block_bits))
#define bucket_pages(c) ((c)->sb.bucket_size / PAGE_SECTORS)
#define bucket_bytes(c) ((c)->sb.bucket_size << 9)
#define block_bytes(c) ((c)->sb.block_size << 9)
#define prios_per_bucket(c) \
((bucket_bytes(c) - sizeof(struct prio_set)) / \
sizeof(struct bucket_disk))
#define prio_buckets(c) \
DIV_ROUND_UP((size_t) (c)->sb.nbuckets, prios_per_bucket(c))
static inline size_t sector_to_bucket(struct cache_set *c, sector_t s)
{
return s >> c->bucket_bits;
}
static inline sector_t bucket_to_sector(struct cache_set *c, size_t b)
{
return ((sector_t) b) << c->bucket_bits;
}
static inline sector_t bucket_remainder(struct cache_set *c, sector_t s)
{
return s & (c->sb.bucket_size - 1);
}
static inline struct cache *PTR_CACHE(struct cache_set *c,
const struct bkey *k,
unsigned ptr)
{
return c->cache[PTR_DEV(k, ptr)];
}
static inline size_t PTR_BUCKET_NR(struct cache_set *c,
const struct bkey *k,
unsigned ptr)
{
return sector_to_bucket(c, PTR_OFFSET(k, ptr));
}
static inline struct bucket *PTR_BUCKET(struct cache_set *c,
const struct bkey *k,
unsigned ptr)
{
return PTR_CACHE(c, k, ptr)->buckets + PTR_BUCKET_NR(c, k, ptr);
}
static inline uint8_t gen_after(uint8_t a, uint8_t b)
{
uint8_t r = a - b;
return r > 128U ? 0 : r;
}
static inline uint8_t ptr_stale(struct cache_set *c, const struct bkey *k,
unsigned i)
{
return gen_after(PTR_BUCKET(c, k, i)->gen, PTR_GEN(k, i));
}
static inline bool ptr_available(struct cache_set *c, const struct bkey *k,
unsigned i)
{
return (PTR_DEV(k, i) < MAX_CACHES_PER_SET) && PTR_CACHE(c, k, i);
}
/* Btree key macros */
/*
* This is used for various on disk data structures - cache_sb, prio_set, bset,
* jset: The checksum is _always_ the first 8 bytes of these structs
*/
#define csum_set(i) \
bch_crc64(((void *) (i)) + sizeof(uint64_t), \
((void *) bset_bkey_last(i)) - \
(((void *) (i)) + sizeof(uint64_t)))
/* Error handling macros */
#define btree_bug(b, ...) \
do { \
if (bch_cache_set_error((b)->c, __VA_ARGS__)) \
dump_stack(); \
} while (0)
#define cache_bug(c, ...) \
do { \
if (bch_cache_set_error(c, __VA_ARGS__)) \
dump_stack(); \
} while (0)
#define btree_bug_on(cond, b, ...) \
do { \
if (cond) \
btree_bug(b, __VA_ARGS__); \
} while (0)
#define cache_bug_on(cond, c, ...) \
do { \
if (cond) \
cache_bug(c, __VA_ARGS__); \
} while (0)
#define cache_set_err_on(cond, c, ...) \
do { \
if (cond) \
bch_cache_set_error(c, __VA_ARGS__); \
} while (0)
/* Looping macros */
#define for_each_cache(ca, cs, iter) \
for (iter = 0; ca = cs->cache[iter], iter < (cs)->sb.nr_in_set; iter++)
#define for_each_bucket(b, ca) \
for (b = (ca)->buckets + (ca)->sb.first_bucket; \
b < (ca)->buckets + (ca)->sb.nbuckets; b++)
static inline void cached_dev_put(struct cached_dev *dc)
{
if (atomic_dec_and_test(&dc->count))
schedule_work(&dc->detach);
}
static inline bool cached_dev_get(struct cached_dev *dc)
{
if (!atomic_inc_not_zero(&dc->count))
return false;
/* Paired with the mb in cached_dev_attach */
smp_mb__after_atomic();
return true;
}
/*
* bucket_gc_gen() returns the difference between the bucket's current gen and
* the oldest gen of any pointer into that bucket in the btree (last_gc).
*/
static inline uint8_t bucket_gc_gen(struct bucket *b)
{
return b->gen - b->last_gc;
}
#define BUCKET_GC_GEN_MAX 96U
#define kobj_attribute_write(n, fn) \
static struct kobj_attribute ksysfs_##n = __ATTR(n, S_IWUSR, NULL, fn)
#define kobj_attribute_rw(n, show, store) \
static struct kobj_attribute ksysfs_##n = \
__ATTR(n, S_IWUSR|S_IRUSR, show, store)
static inline void wake_up_allocators(struct cache_set *c)
{
struct cache *ca;
unsigned i;
for_each_cache(ca, c, i)
wake_up_process(ca->alloc_thread);
}
/* Forward declarations */
void bch_count_io_errors(struct cache *, int, const char *);
void bch_bbio_count_io_errors(struct cache_set *, struct bio *,
int, const char *);
void bch_bbio_endio(struct cache_set *, struct bio *, int, const char *);
void bch_bbio_free(struct bio *, struct cache_set *);
struct bio *bch_bbio_alloc(struct cache_set *);
void __bch_submit_bbio(struct bio *, struct cache_set *);
void bch_submit_bbio(struct bio *, struct cache_set *, struct bkey *, unsigned);
uint8_t bch_inc_gen(struct cache *, struct bucket *);
void bch_rescale_priorities(struct cache_set *, int);
bool bch_can_invalidate_bucket(struct cache *, struct bucket *);
void __bch_invalidate_one_bucket(struct cache *, struct bucket *);
void __bch_bucket_free(struct cache *, struct bucket *);
void bch_bucket_free(struct cache_set *, struct bkey *);
long bch_bucket_alloc(struct cache *, unsigned, bool);
int __bch_bucket_alloc_set(struct cache_set *, unsigned,
struct bkey *, int, bool);
int bch_bucket_alloc_set(struct cache_set *, unsigned,
struct bkey *, int, bool);
bool bch_alloc_sectors(struct cache_set *, struct bkey *, unsigned,
unsigned, unsigned, bool);
__printf(2, 3)
bool bch_cache_set_error(struct cache_set *, const char *, ...);
void bch_prio_write(struct cache *);
void bch_write_bdev_super(struct cached_dev *, struct closure *);
extern struct workqueue_struct *bcache_wq;
extern const char * const bch_cache_modes[];
extern struct mutex bch_register_lock;
extern struct list_head bch_cache_sets;
extern struct kobj_type bch_cached_dev_ktype;
extern struct kobj_type bch_flash_dev_ktype;
extern struct kobj_type bch_cache_set_ktype;
extern struct kobj_type bch_cache_set_internal_ktype;
extern struct kobj_type bch_cache_ktype;
void bch_cached_dev_release(struct kobject *);
void bch_flash_dev_release(struct kobject *);
void bch_cache_set_release(struct kobject *);
void bch_cache_release(struct kobject *);
int bch_uuid_write(struct cache_set *);
void bcache_write_super(struct cache_set *);
int bch_flash_dev_create(struct cache_set *c, uint64_t size);
int bch_cached_dev_attach(struct cached_dev *, struct cache_set *);
void bch_cached_dev_detach(struct cached_dev *);
void bch_cached_dev_run(struct cached_dev *);
void bcache_device_stop(struct bcache_device *);
void bch_cache_set_unregister(struct cache_set *);
void bch_cache_set_stop(struct cache_set *);
struct cache_set *bch_cache_set_alloc(struct cache_sb *);
void bch_btree_cache_free(struct cache_set *);
int bch_btree_cache_alloc(struct cache_set *);
void bch_moving_init_cache_set(struct cache_set *);
int bch_open_buckets_alloc(struct cache_set *);
void bch_open_buckets_free(struct cache_set *);
int bch_cache_allocator_start(struct cache *ca);
void bch_debug_exit(void);
int bch_debug_init(struct kobject *);
void bch_request_exit(void);
int bch_request_init(void);
#endif /* _BCACHE_H */