/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_H
#define _BCACHEFS_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 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()).
*/
#undef pr_fmt
#ifdef __KERNEL__
#define pr_fmt(fmt) "bcachefs: %s() " fmt "\n", __func__
#else
#define pr_fmt(fmt) "%s() " fmt "\n", __func__
#endif
#include <linux/backing-dev-defs.h>
#include <linux/bug.h>
#include <linux/bio.h>
#include <linux/closure.h>
#include <linux/kobject.h>
#include <linux/list.h>
#include <linux/math64.h>
#include <linux/mutex.h>
#include <linux/percpu-refcount.h>
#include <linux/percpu-rwsem.h>
#include <linux/refcount.h>
#include <linux/rhashtable.h>
#include <linux/rwsem.h>
#include <linux/semaphore.h>
#include <linux/seqlock.h>
#include <linux/shrinker.h>
#include <linux/srcu.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/zstd.h>
#include "bcachefs_format.h"
#include "disk_accounting_types.h"
#include "errcode.h"
#include "fifo.h"
#include "nocow_locking_types.h"
#include "opts.h"
#include "recovery_passes_types.h"
#include "sb-errors_types.h"
#include "seqmutex.h"
#include "time_stats.h"
#include "util.h"
#ifdef CONFIG_BCACHEFS_DEBUG
#define BCH_WRITE_REF_DEBUG
#endif
#ifndef dynamic_fault
#define dynamic_fault(...) 0
#endif
#define race_fault(...) dynamic_fault("bcachefs:race")
#define count_event(_c, _name) this_cpu_inc((_c)->counters[BCH_COUNTER_##_name])
#define trace_and_count(_c, _name, ...) \
do { \
count_event(_c, _name); \
trace_##_name(__VA_ARGS__); \
} while (0)
#define bch2_fs_init_fault(name) \
dynamic_fault("bcachefs:bch_fs_init:" name)
#define bch2_meta_read_fault(name) \
dynamic_fault("bcachefs:meta:read:" name)
#define bch2_meta_write_fault(name) \
dynamic_fault("bcachefs:meta:write:" name)
#ifdef __KERNEL__
#define BCACHEFS_LOG_PREFIX
#endif
#ifdef BCACHEFS_LOG_PREFIX
#define bch2_log_msg(_c, fmt) "bcachefs (%s): " fmt, ((_c)->name)
#define bch2_fmt_dev(_ca, fmt) "bcachefs (%s): " fmt "\n", ((_ca)->name)
#define bch2_fmt_dev_offset(_ca, _offset, fmt) "bcachefs (%s sector %llu): " fmt "\n", ((_ca)->name), (_offset)
#define bch2_fmt_inum(_c, _inum, fmt) "bcachefs (%s inum %llu): " fmt "\n", ((_c)->name), (_inum)
#define bch2_fmt_inum_offset(_c, _inum, _offset, fmt) \
"bcachefs (%s inum %llu offset %llu): " fmt "\n", ((_c)->name), (_inum), (_offset)
#else
#define bch2_log_msg(_c, fmt) fmt
#define bch2_fmt_dev(_ca, fmt) "%s: " fmt "\n", ((_ca)->name)
#define bch2_fmt_dev_offset(_ca, _offset, fmt) "%s sector %llu: " fmt "\n", ((_ca)->name), (_offset)
#define bch2_fmt_inum(_c, _inum, fmt) "inum %llu: " fmt "\n", (_inum)
#define bch2_fmt_inum_offset(_c, _inum, _offset, fmt) \
"inum %llu offset %llu: " fmt "\n", (_inum), (_offset)
#endif
#define bch2_fmt(_c, fmt) bch2_log_msg(_c, fmt "\n")
void bch2_print_str(struct bch_fs *, const char *);
__printf(2, 3)
void bch2_print_opts(struct bch_opts *, const char *, ...);
__printf(2, 3)
void __bch2_print(struct bch_fs *c, const char *fmt, ...);
#define maybe_dev_to_fs(_c) _Generic((_c), \
struct bch_dev *: ((struct bch_dev *) (_c))->fs, \
struct bch_fs *: (_c))
#define bch2_print(_c, ...) __bch2_print(maybe_dev_to_fs(_c), __VA_ARGS__)
#define bch2_print_ratelimited(_c, ...) \
do { \
static DEFINE_RATELIMIT_STATE(_rs, \
DEFAULT_RATELIMIT_INTERVAL, \
DEFAULT_RATELIMIT_BURST); \
\
if (__ratelimit(&_rs)) \
bch2_print(_c, __VA_ARGS__); \
} while (0)
#define bch_info(c, fmt, ...) \
bch2_print(c, KERN_INFO bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_notice(c, fmt, ...) \
bch2_print(c, KERN_NOTICE bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_warn(c, fmt, ...) \
bch2_print(c, KERN_WARNING bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_warn_ratelimited(c, fmt, ...) \
bch2_print_ratelimited(c, KERN_WARNING bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_err(c, fmt, ...) \
bch2_print(c, KERN_ERR bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_err_dev(ca, fmt, ...) \
bch2_print(c, KERN_ERR bch2_fmt_dev(ca, fmt), ##__VA_ARGS__)
#define bch_err_dev_offset(ca, _offset, fmt, ...) \
bch2_print(c, KERN_ERR bch2_fmt_dev_offset(ca, _offset, fmt), ##__VA_ARGS__)
#define bch_err_inum(c, _inum, fmt, ...) \
bch2_print(c, KERN_ERR bch2_fmt_inum(c, _inum, fmt), ##__VA_ARGS__)
#define bch_err_inum_offset(c, _inum, _offset, fmt, ...) \
bch2_print(c, KERN_ERR bch2_fmt_inum_offset(c, _inum, _offset, fmt), ##__VA_ARGS__)
#define bch_err_ratelimited(c, fmt, ...) \
bch2_print_ratelimited(c, KERN_ERR bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_err_dev_ratelimited(ca, fmt, ...) \
bch2_print_ratelimited(ca, KERN_ERR bch2_fmt_dev(ca, fmt), ##__VA_ARGS__)
#define bch_err_dev_offset_ratelimited(ca, _offset, fmt, ...) \
bch2_print_ratelimited(ca, KERN_ERR bch2_fmt_dev_offset(ca, _offset, fmt), ##__VA_ARGS__)
#define bch_err_inum_ratelimited(c, _inum, fmt, ...) \
bch2_print_ratelimited(c, KERN_ERR bch2_fmt_inum(c, _inum, fmt), ##__VA_ARGS__)
#define bch_err_inum_offset_ratelimited(c, _inum, _offset, fmt, ...) \
bch2_print_ratelimited(c, KERN_ERR bch2_fmt_inum_offset(c, _inum, _offset, fmt), ##__VA_ARGS__)
static inline bool should_print_err(int err)
{
return err && !bch2_err_matches(err, BCH_ERR_transaction_restart);
}
#define bch_err_fn(_c, _ret) \
do { \
if (should_print_err(_ret)) \
bch_err(_c, "%s(): error %s", __func__, bch2_err_str(_ret));\
} while (0)
#define bch_err_fn_ratelimited(_c, _ret) \
do { \
if (should_print_err(_ret)) \
bch_err_ratelimited(_c, "%s(): error %s", __func__, bch2_err_str(_ret));\
} while (0)
#define bch_err_msg(_c, _ret, _msg, ...) \
do { \
if (should_print_err(_ret)) \
bch_err(_c, "%s(): error " _msg " %s", __func__, \
##__VA_ARGS__, bch2_err_str(_ret)); \
} while (0)
#define bch_verbose(c, fmt, ...) \
do { \
if ((c)->opts.verbose) \
bch_info(c, fmt, ##__VA_ARGS__); \
} while (0)
#define pr_verbose_init(opts, fmt, ...) \
do { \
if (opt_get(opts, verbose)) \
pr_info(fmt, ##__VA_ARGS__); \
} while (0)
/* Parameters that are useful for debugging, but should always be compiled in: */
#define BCH_DEBUG_PARAMS_ALWAYS() \
BCH_DEBUG_PARAM(key_merging_disabled, \
"Disables merging of extents") \
BCH_DEBUG_PARAM(btree_node_merging_disabled, \
"Disables merging of btree nodes") \
BCH_DEBUG_PARAM(btree_gc_always_rewrite, \
"Causes mark and sweep to compact and rewrite every " \
"btree node it traverses") \
BCH_DEBUG_PARAM(btree_gc_rewrite_disabled, \
"Disables rewriting of btree nodes during mark and sweep")\
BCH_DEBUG_PARAM(btree_shrinker_disabled, \
"Disables the shrinker callback for the btree node cache")\
BCH_DEBUG_PARAM(verify_btree_ondisk, \
"Reread btree nodes at various points to verify the " \
"mergesort in the read path against modifications " \
"done in memory") \
BCH_DEBUG_PARAM(verify_all_btree_replicas, \
"When reading btree nodes, read all replicas and " \
"compare them") \
BCH_DEBUG_PARAM(backpointers_no_use_write_buffer, \
"Don't use the write buffer for backpointers, enabling "\
"extra runtime checks")
/* Parameters that should only be compiled in debug mode: */
#define BCH_DEBUG_PARAMS_DEBUG() \
BCH_DEBUG_PARAM(expensive_debug_checks, \
"Enables various runtime debugging checks that " \
"significantly affect performance") \
BCH_DEBUG_PARAM(debug_check_iterators, \
"Enables extra verification for btree iterators") \
BCH_DEBUG_PARAM(debug_check_btree_accounting, \
"Verify btree accounting for keys within a node") \
BCH_DEBUG_PARAM(journal_seq_verify, \
"Store the journal sequence number in the version " \
"number of every btree key, and verify that btree " \
"update ordering is preserved during recovery") \
BCH_DEBUG_PARAM(inject_invalid_keys, \
"Store the journal sequence number in the version " \
"number of every btree key, and verify that btree " \
"update ordering is preserved during recovery") \
BCH_DEBUG_PARAM(test_alloc_startup, \
"Force allocator startup to use the slowpath where it" \
"can't find enough free buckets without invalidating" \
"cached data") \
BCH_DEBUG_PARAM(force_reconstruct_read, \
"Force reads to use the reconstruct path, when reading" \
"from erasure coded extents") \
BCH_DEBUG_PARAM(test_restart_gc, \
"Test restarting mark and sweep gc when bucket gens change")
#define BCH_DEBUG_PARAMS_ALL() BCH_DEBUG_PARAMS_ALWAYS() BCH_DEBUG_PARAMS_DEBUG()
#ifdef CONFIG_BCACHEFS_DEBUG
#define BCH_DEBUG_PARAMS() BCH_DEBUG_PARAMS_ALL()
#else
#define BCH_DEBUG_PARAMS() BCH_DEBUG_PARAMS_ALWAYS()
#endif
#define BCH_DEBUG_PARAM(name, description) extern bool bch2_##name;
BCH_DEBUG_PARAMS()
#undef BCH_DEBUG_PARAM
#ifndef CONFIG_BCACHEFS_DEBUG
#define BCH_DEBUG_PARAM(name, description) static const __maybe_unused bool bch2_##name;
BCH_DEBUG_PARAMS_DEBUG()
#undef BCH_DEBUG_PARAM
#endif
#define BCH_TIME_STATS() \
x(btree_node_mem_alloc) \
x(btree_node_split) \
x(btree_node_compact) \
x(btree_node_merge) \
x(btree_node_sort) \
x(btree_node_read) \
x(btree_node_read_done) \
x(btree_interior_update_foreground) \
x(btree_interior_update_total) \
x(btree_gc) \
x(data_write) \
x(data_read) \
x(data_promote) \
x(journal_flush_write) \
x(journal_noflush_write) \
x(journal_flush_seq) \
x(blocked_journal_low_on_space) \
x(blocked_journal_low_on_pin) \
x(blocked_journal_max_in_flight) \
x(blocked_key_cache_flush) \
x(blocked_allocate) \
x(blocked_allocate_open_bucket) \
x(blocked_write_buffer_full) \
x(nocow_lock_contended)
enum bch_time_stats {
#define x(name) BCH_TIME_##name,
BCH_TIME_STATS()
#undef x
BCH_TIME_STAT_NR
};
#include "alloc_types.h"
#include "btree_gc_types.h"
#include "btree_types.h"
#include "btree_node_scan_types.h"
#include "btree_write_buffer_types.h"
#include "buckets_types.h"
#include "buckets_waiting_for_journal_types.h"
#include "clock_types.h"
#include "disk_groups_types.h"
#include "ec_types.h"
#include "journal_types.h"
#include "keylist_types.h"
#include "quota_types.h"
#include "rebalance_types.h"
#include "replicas_types.h"
#include "sb-members_types.h"
#include "subvolume_types.h"
#include "super_types.h"
#include "thread_with_file_types.h"
/* Number of nodes btree coalesce will try to coalesce at once */
#define GC_MERGE_NODES 4U
/* Maximum number of nodes we might need to allocate atomically: */
#define BTREE_RESERVE_MAX (BTREE_MAX_DEPTH + (BTREE_MAX_DEPTH - 1))
/* Size of the freelist we allocate btree nodes from: */
#define BTREE_NODE_RESERVE (BTREE_RESERVE_MAX * 4)
#define BTREE_NODE_OPEN_BUCKET_RESERVE (BTREE_RESERVE_MAX * BCH_REPLICAS_MAX)
struct btree;
struct io_count {
u64 sectors[2][BCH_DATA_NR];
};
struct discard_in_flight {
bool in_progress:1;
u64 bucket:63;
};
struct bch_dev {
struct kobject kobj;
#ifdef CONFIG_BCACHEFS_DEBUG
atomic_long_t ref;
bool dying;
unsigned long last_put;
#else
struct percpu_ref ref;
#endif
struct completion ref_completion;
struct percpu_ref io_ref;
struct completion io_ref_completion;
struct bch_fs *fs;
u8 dev_idx;
/*
* Cached version of this device's member info from superblock
* Committed by bch2_write_super() -> bch_fs_mi_update()
*/
struct bch_member_cpu mi;
atomic64_t errors[BCH_MEMBER_ERROR_NR];
__uuid_t uuid;
char name[BDEVNAME_SIZE];
struct bch_sb_handle disk_sb;
struct bch_sb *sb_read_scratch;
int sb_write_error;
dev_t dev;
atomic_t flush_seq;
struct bch_devs_mask self;
/*
* Buckets:
* Per-bucket arrays are protected by c->mark_lock, bucket_lock and
* gc_gens_lock, for device resize - holding any is sufficient for
* access: Or rcu_read_lock(), but only for dev_ptr_stale():
*/
GENRADIX(struct bucket) buckets_gc;
struct bucket_gens __rcu *bucket_gens;
u8 *oldest_gen;
unsigned long *buckets_nouse;
struct rw_semaphore bucket_lock;
struct bch_dev_usage __percpu *usage;
/* Allocator: */
u64 new_fs_bucket_idx;
u64 alloc_cursor[3];
unsigned nr_open_buckets;
unsigned nr_btree_reserve;
size_t inc_gen_needs_gc;
size_t inc_gen_really_needs_gc;
size_t buckets_waiting_on_journal;
struct work_struct invalidate_work;
struct work_struct discard_work;
struct mutex discard_buckets_in_flight_lock;
DARRAY(struct discard_in_flight) discard_buckets_in_flight;
struct work_struct discard_fast_work;
atomic64_t rebalance_work;
struct journal_device journal;
u64 prev_journal_sector;
struct work_struct io_error_work;
/* The rest of this all shows up in sysfs */
atomic64_t cur_latency[2];
struct bch2_time_stats_quantiles io_latency[2];
#define CONGESTED_MAX 1024
atomic_t congested;
u64 congested_last;
struct io_count __percpu *io_done;
};
/*
* initial_gc_unfixed
* error
* topology error
*/
#define BCH_FS_FLAGS() \
x(new_fs) \
x(started) \
x(clean_recovery) \
x(btree_running) \
x(accounting_replay_done) \
x(may_go_rw) \
x(rw) \
x(was_rw) \
x(stopping) \
x(emergency_ro) \
x(going_ro) \
x(write_disable_complete) \
x(clean_shutdown) \
x(fsck_running) \
x(initial_gc_unfixed) \
x(need_delete_dead_snapshots) \
x(error) \
x(topology_error) \
x(errors_fixed) \
x(errors_not_fixed) \
x(no_invalid_checks)
enum bch_fs_flags {
#define x(n) BCH_FS_##n,
BCH_FS_FLAGS()
#undef x
};
struct btree_debug {
unsigned id;
};
#define BCH_TRANSACTIONS_NR 128
struct btree_transaction_stats {
struct bch2_time_stats duration;
struct bch2_time_stats lock_hold_times;
struct mutex lock;
unsigned nr_max_paths;
unsigned journal_entries_size;
unsigned max_mem;
char *max_paths_text;
};
struct bch_fs_pcpu {
u64 sectors_available;
};
struct journal_seq_blacklist_table {
size_t nr;
struct journal_seq_blacklist_table_entry {
u64 start;
u64 end;
bool dirty;
} entries[];
};
struct journal_keys {
/* must match layout in darray_types.h */
size_t nr, size;
struct journal_key {
u64 journal_seq;
u32 journal_offset;
enum btree_id btree_id:8;
unsigned level:8;
bool allocated;
bool overwritten;
struct bkey_i *k;
} *data;
/*
* Gap buffer: instead of all the empty space in the array being at the
* end of the buffer - from @nr to @size - the empty space is at @gap.
* This means that sequential insertions are O(n) instead of O(n^2).
*/
size_t gap;
atomic_t ref;
bool initial_ref_held;
};
struct btree_trans_buf {
struct btree_trans *trans;
};
#define BCACHEFS_ROOT_SUBVOL_INUM \
((subvol_inum) { BCACHEFS_ROOT_SUBVOL, BCACHEFS_ROOT_INO })
#define BCH_WRITE_REFS() \
x(trans) \
x(write) \
x(promote) \
x(node_rewrite) \
x(stripe_create) \
x(stripe_delete) \
x(reflink) \
x(fallocate) \
x(fsync) \
x(dio_write) \
x(discard) \
x(discard_fast) \
x(invalidate) \
x(delete_dead_snapshots) \
x(gc_gens) \
x(snapshot_delete_pagecache) \
x(sysfs) \
x(btree_write_buffer)
enum bch_write_ref {
#define x(n) BCH_WRITE_REF_##n,
BCH_WRITE_REFS()
#undef x
BCH_WRITE_REF_NR,
};
struct bch_fs {
struct closure cl;
struct list_head list;
struct kobject kobj;
struct kobject counters_kobj;
struct kobject internal;
struct kobject opts_dir;
struct kobject time_stats;
unsigned long flags;
int minor;
struct device *chardev;
struct super_block *vfs_sb;
dev_t dev;
char name[40];
struct stdio_redirect *stdio;
struct task_struct *stdio_filter;
/* ro/rw, add/remove/resize devices: */
struct rw_semaphore state_lock;
/* Counts outstanding writes, for clean transition to read-only */
#ifdef BCH_WRITE_REF_DEBUG
atomic_long_t writes[BCH_WRITE_REF_NR];
#else
struct percpu_ref writes;
#endif
/*
* Analagous to c->writes, for asynchronous ops that don't necessarily
* need fs to be read-write
*/
refcount_t ro_ref;
wait_queue_head_t ro_ref_wait;
struct work_struct read_only_work;
struct bch_dev __rcu *devs[BCH_SB_MEMBERS_MAX];
struct bch_accounting_mem accounting;
struct bch_replicas_cpu replicas;
struct bch_replicas_cpu replicas_gc;
struct mutex replicas_gc_lock;
struct journal_entry_res btree_root_journal_res;
struct journal_entry_res clock_journal_res;
struct bch_disk_groups_cpu __rcu *disk_groups;
struct bch_opts opts;
/* Updated by bch2_sb_update():*/
struct {
__uuid_t uuid;
__uuid_t user_uuid;
u16 version;
u16 version_min;
u16 version_upgrade_complete;
u8 nr_devices;
u8 clean;
u8 encryption_type;
u64 time_base_lo;
u32 time_base_hi;
unsigned time_units_per_sec;
unsigned nsec_per_time_unit;
u64 features;
u64 compat;
unsigned long errors_silent[BITS_TO_LONGS(BCH_FSCK_ERR_MAX)];
u64 btrees_lost_data;
} sb;
struct bch_sb_handle disk_sb;
unsigned short block_bits; /* ilog2(block_size) */
u16 btree_foreground_merge_threshold;
struct closure sb_write;
struct mutex sb_lock;
/* snapshot.c: */
struct snapshot_table __rcu *snapshots;
struct mutex snapshot_table_lock;
struct rw_semaphore snapshot_create_lock;
struct work_struct snapshot_delete_work;
struct work_struct snapshot_wait_for_pagecache_and_delete_work;
snapshot_id_list snapshots_unlinked;
struct mutex snapshots_unlinked_lock;
/* BTREE CACHE */
struct bio_set btree_bio;
struct workqueue_struct *btree_read_complete_wq;
struct workqueue_struct *btree_write_submit_wq;
struct btree_root btree_roots_known[BTREE_ID_NR];
DARRAY(struct btree_root) btree_roots_extra;
struct mutex btree_root_lock;
struct btree_cache btree_cache;
/*
* Cache of allocated btree nodes - if we allocate a btree node and
* don't use it, if we free it that space can't be reused until going
* _all_ the way through the allocator (which exposes us to a livelock
* when allocating btree reserves fail halfway through) - instead, we
* can stick them here:
*/
struct btree_alloc btree_reserve_cache[BTREE_NODE_RESERVE * 2];
unsigned btree_reserve_cache_nr;
struct mutex btree_reserve_cache_lock;
mempool_t btree_interior_update_pool;
struct list_head btree_interior_update_list;
struct list_head btree_interior_updates_unwritten;
struct mutex btree_interior_update_lock;
struct closure_waitlist btree_interior_update_wait;
struct workqueue_struct *btree_interior_update_worker;
struct work_struct btree_interior_update_work;
struct workqueue_struct *btree_node_rewrite_worker;
struct list_head pending_node_rewrites;
struct mutex pending_node_rewrites_lock;
/* btree_io.c: */
spinlock_t btree_write_error_lock;
struct btree_write_stats {
atomic64_t nr;
atomic64_t bytes;
} btree_write_stats[BTREE_WRITE_TYPE_NR];
/* btree_iter.c: */
struct seqmutex btree_trans_lock;
struct list_head btree_trans_list;
mempool_t btree_trans_pool;
mempool_t btree_trans_mem_pool;
struct btree_trans_buf __percpu *btree_trans_bufs;
struct srcu_struct btree_trans_barrier;
bool btree_trans_barrier_initialized;
struct btree_key_cache btree_key_cache;
unsigned btree_key_cache_btrees;
struct btree_write_buffer btree_write_buffer;
struct workqueue_struct *btree_update_wq;
struct workqueue_struct *btree_io_complete_wq;
/* copygc needs its own workqueue for index updates.. */
struct workqueue_struct *copygc_wq;
/*
* Use a dedicated wq for write ref holder tasks. Required to avoid
* dependency problems with other wq tasks that can block on ref
* draining, such as read-only transition.
*/
struct workqueue_struct *write_ref_wq;
/* ALLOCATION */
struct bch_devs_mask rw_devs[BCH_DATA_NR];
unsigned long rw_devs_change_count;
u64 capacity; /* sectors */
u64 reserved; /* sectors */
/*
* When capacity _decreases_ (due to a disk being removed), we
* increment capacity_gen - this invalidates outstanding reservations
* and forces them to be revalidated
*/
u32 capacity_gen;
unsigned bucket_size_max;
atomic64_t sectors_available;
struct mutex sectors_available_lock;
struct bch_fs_pcpu __percpu *pcpu;
struct percpu_rw_semaphore mark_lock;
seqcount_t usage_lock;
struct bch_fs_usage_base __percpu *usage;
u64 __percpu *online_reserved;
unsigned long allocator_last_stuck;
struct io_clock io_clock[2];
/* JOURNAL SEQ BLACKLIST */
struct journal_seq_blacklist_table *
journal_seq_blacklist_table;
/* ALLOCATOR */
spinlock_t freelist_lock;
struct closure_waitlist freelist_wait;
open_bucket_idx_t open_buckets_freelist;
open_bucket_idx_t open_buckets_nr_free;
struct closure_waitlist open_buckets_wait;
struct open_bucket open_buckets[OPEN_BUCKETS_COUNT];
open_bucket_idx_t open_buckets_hash[OPEN_BUCKETS_COUNT];
open_bucket_idx_t open_buckets_partial[OPEN_BUCKETS_COUNT];
open_bucket_idx_t open_buckets_partial_nr;
struct write_point btree_write_point;
struct write_point rebalance_write_point;
struct write_point write_points[WRITE_POINT_MAX];
struct hlist_head write_points_hash[WRITE_POINT_HASH_NR];
struct mutex write_points_hash_lock;
unsigned write_points_nr;
struct buckets_waiting_for_journal buckets_waiting_for_journal;
/* GARBAGE COLLECTION */
struct work_struct gc_gens_work;
unsigned long gc_count;
enum btree_id gc_gens_btree;
struct bpos gc_gens_pos;
/*
* Tracks GC's progress - everything in the range [ZERO_KEY..gc_cur_pos]
* has been marked by GC.
*
* gc_cur_phase is a superset of btree_ids (BTREE_ID_extents etc.)
*
* Protected by gc_pos_lock. Only written to by GC thread, so GC thread
* can read without a lock.
*/
seqcount_t gc_pos_lock;
struct gc_pos gc_pos;
/*
* The allocation code needs gc_mark in struct bucket to be correct, but
* it's not while a gc is in progress.
*/
struct rw_semaphore gc_lock;
struct mutex gc_gens_lock;
/* IO PATH */
struct semaphore io_in_flight;
struct bio_set bio_read;
struct bio_set bio_read_split;
struct bio_set bio_write;
struct bio_set replica_set;
struct mutex bio_bounce_pages_lock;
mempool_t bio_bounce_pages;
struct bucket_nocow_lock_table
nocow_locks;
struct rhashtable promote_table;
mempool_t compression_bounce[2];
mempool_t compress_workspace[BCH_COMPRESSION_TYPE_NR];
mempool_t decompress_workspace;
size_t zstd_workspace_size;
struct crypto_shash *sha256;
struct crypto_sync_skcipher *chacha20;
struct crypto_shash *poly1305;
atomic64_t key_version;
mempool_t large_bkey_pool;
/* MOVE.C */
struct list_head moving_context_list;
struct mutex moving_context_lock;
/* REBALANCE */
struct bch_fs_rebalance rebalance;
/* COPYGC */
struct task_struct *copygc_thread;
struct write_point copygc_write_point;
s64 copygc_wait_at;
s64 copygc_wait;
bool copygc_running;
wait_queue_head_t copygc_running_wq;
/* STRIPES: */
GENRADIX(struct stripe) stripes;
GENRADIX(struct gc_stripe) gc_stripes;
struct hlist_head ec_stripes_new[32];
spinlock_t ec_stripes_new_lock;
ec_stripes_heap ec_stripes_heap;
struct mutex ec_stripes_heap_lock;
/* ERASURE CODING */
struct list_head ec_stripe_head_list;
struct mutex ec_stripe_head_lock;
struct list_head ec_stripe_new_list;
struct mutex ec_stripe_new_lock;
wait_queue_head_t ec_stripe_new_wait;
struct work_struct ec_stripe_create_work;
u64 ec_stripe_hint;
struct work_struct ec_stripe_delete_work;
struct bio_set ec_bioset;
/* REFLINK */
reflink_gc_table reflink_gc_table;
size_t reflink_gc_nr;
/* fs.c */
struct list_head vfs_inodes_list;
struct mutex vfs_inodes_lock;
struct rhashtable vfs_inodes_table;
/* VFS IO PATH - fs-io.c */
struct bio_set writepage_bioset;
struct bio_set dio_write_bioset;
struct bio_set dio_read_bioset;
struct bio_set nocow_flush_bioset;
/* QUOTAS */
struct bch_memquota_type quotas[QTYP_NR];
/* RECOVERY */
u64 journal_replay_seq_start;
u64 journal_replay_seq_end;
/*
* Two different uses:
* "Has this fsck pass?" - i.e. should this type of error be an
* emergency read-only
* And, in certain situations fsck will rewind to an earlier pass: used
* for signaling to the toplevel code which pass we want to run now.
*/
enum bch_recovery_pass curr_recovery_pass;
/* bitmask of recovery passes that we actually ran */
u64 recovery_passes_complete;
/* never rewinds version of curr_recovery_pass */
enum bch_recovery_pass recovery_pass_done;
struct semaphore online_fsck_mutex;
/* DEBUG JUNK */
struct dentry *fs_debug_dir;
struct dentry *btree_debug_dir;
struct btree_debug btree_debug[BTREE_ID_NR];
struct btree *verify_data;
struct btree_node *verify_ondisk;
struct mutex verify_lock;
u64 *unused_inode_hints;
unsigned inode_shard_bits;
/*
* 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;
mempool_t btree_bounce_pool;
struct journal journal;
GENRADIX(struct journal_replay *) journal_entries;
u64 journal_entries_base_seq;
struct journal_keys journal_keys;
struct list_head journal_iters;
struct find_btree_nodes found_btree_nodes;
u64 last_bucket_seq_cleanup;
u64 counters_on_mount[BCH_COUNTER_NR];
u64 __percpu *counters;
unsigned copy_gc_enabled:1;
struct bch2_time_stats times[BCH_TIME_STAT_NR];
struct btree_transaction_stats btree_transaction_stats[BCH_TRANSACTIONS_NR];
/* ERRORS */
struct list_head fsck_error_msgs;
struct mutex fsck_error_msgs_lock;
bool fsck_alloc_msgs_err;
bch_sb_errors_cpu fsck_error_counts;
struct mutex fsck_error_counts_lock;
};
extern struct wait_queue_head bch2_read_only_wait;
static inline void bch2_write_ref_get(struct bch_fs *c, enum bch_write_ref ref)
{
#ifdef BCH_WRITE_REF_DEBUG
atomic_long_inc(&c->writes[ref]);
#else
percpu_ref_get(&c->writes);
#endif
}
static inline bool __bch2_write_ref_tryget(struct bch_fs *c, enum bch_write_ref ref)
{
#ifdef BCH_WRITE_REF_DEBUG
return !test_bit(BCH_FS_going_ro, &c->flags) &&
atomic_long_inc_not_zero(&c->writes[ref]);
#else
return percpu_ref_tryget(&c->writes);
#endif
}
static inline bool bch2_write_ref_tryget(struct bch_fs *c, enum bch_write_ref ref)
{
#ifdef BCH_WRITE_REF_DEBUG
return !test_bit(BCH_FS_going_ro, &c->flags) &&
atomic_long_inc_not_zero(&c->writes[ref]);
#else
return percpu_ref_tryget_live(&c->writes);
#endif
}
static inline void bch2_write_ref_put(struct bch_fs *c, enum bch_write_ref ref)
{
#ifdef BCH_WRITE_REF_DEBUG
long v = atomic_long_dec_return(&c->writes[ref]);
BUG_ON(v < 0);
if (v)
return;
for (unsigned i = 0; i < BCH_WRITE_REF_NR; i++)
if (atomic_long_read(&c->writes[i]))
return;
set_bit(BCH_FS_write_disable_complete, &c->flags);
wake_up(&bch2_read_only_wait);
#else
percpu_ref_put(&c->writes);
#endif
}
static inline bool bch2_ro_ref_tryget(struct bch_fs *c)
{
if (test_bit(BCH_FS_stopping, &c->flags))
return false;
return refcount_inc_not_zero(&c->ro_ref);
}
static inline void bch2_ro_ref_put(struct bch_fs *c)
{
if (refcount_dec_and_test(&c->ro_ref))
wake_up(&c->ro_ref_wait);
}
static inline void bch2_set_ra_pages(struct bch_fs *c, unsigned ra_pages)
{
#ifndef NO_BCACHEFS_FS
if (c->vfs_sb)
c->vfs_sb->s_bdi->ra_pages = ra_pages;
#endif
}
static inline unsigned bucket_bytes(const struct bch_dev *ca)
{
return ca->mi.bucket_size << 9;
}
static inline unsigned block_bytes(const struct bch_fs *c)
{
return c->opts.block_size;
}
static inline unsigned block_sectors(const struct bch_fs *c)
{
return c->opts.block_size >> 9;
}
static inline bool btree_id_cached(const struct bch_fs *c, enum btree_id btree)
{
return c->btree_key_cache_btrees & (1U << btree);
}
static inline struct timespec64 bch2_time_to_timespec(const struct bch_fs *c, s64 time)
{
struct timespec64 t;
s64 sec;
s32 rem;
time += c->sb.time_base_lo;
sec = div_s64_rem(time, c->sb.time_units_per_sec, &rem);
set_normalized_timespec64(&t, sec, rem * (s64)c->sb.nsec_per_time_unit);
return t;
}
static inline s64 timespec_to_bch2_time(const struct bch_fs *c, struct timespec64 ts)
{
return (ts.tv_sec * c->sb.time_units_per_sec +
(int) ts.tv_nsec / c->sb.nsec_per_time_unit) - c->sb.time_base_lo;
}
static inline s64 bch2_current_time(const struct bch_fs *c)
{
struct timespec64 now;
ktime_get_coarse_real_ts64(&now);
return timespec_to_bch2_time(c, now);
}
static inline u64 bch2_current_io_time(const struct bch_fs *c, int rw)
{
return max(1ULL, (u64) atomic64_read(&c->io_clock[rw].now) & LRU_TIME_MAX);
}
static inline struct stdio_redirect *bch2_fs_stdio_redirect(struct bch_fs *c)
{
struct stdio_redirect *stdio = c->stdio;
if (c->stdio_filter && c->stdio_filter != current)
stdio = NULL;
return stdio;
}
static inline unsigned metadata_replicas_required(struct bch_fs *c)
{
return min(c->opts.metadata_replicas,
c->opts.metadata_replicas_required);
}
static inline unsigned data_replicas_required(struct bch_fs *c)
{
return min(c->opts.data_replicas,
c->opts.data_replicas_required);
}
#define BKEY_PADDED_ONSTACK(key, pad) \
struct { struct bkey_i key; __u64 key ## _pad[pad]; }
#endif /* _BCACHEFS_H */
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