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linux/fs/bcachefs/bcachefs.h
Brian Foster 8bff9875a6 bcachefs: use dedicated workqueue for tasks holding write refs 
A workqueue resource deadlock has been observed when running fsck
on a filesystem with a full/stuck journal. fsck is not currently
able to repair the fs due to fairly rapid emergency shutdown, but
rather than exit gracefully the fsck process hangs during the
shutdown sequence. Fortunately this is easily recoverable from
userspace, but the root cause involves code shared between the
kernel and userspace and so should be addressed.

The deadlock scenario involves the main task in the bch2_fs_stop()
-> bch2_fs_read_only() path waiting on write references to drain
with the fs state lock held. A bch2_read_only_work() workqueue task
is scheduled on the system_long_wq, blocked on the state lock.
Finally, various other write ref holding workqueue tasks are
scheduled to run on the same workqueue and must complete in order to
release references that the initial task is waiting on.

To avoid this problem, we can split the dependent workqueue tasks
across different workqueues. It's a bit of a waste to create a
dedicated wq for the read-only worker, but there are several tasks
throughout the fs that follow the pattern of acquiring a write
reference and then scheduling to the system wq. Use a local wq
for such tasks to break the subtle dependency between these and the
read-only worker.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:58 -04:00

1145 lines
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/* 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/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 "errcode.h"
#include "fifo.h"
#include "nocow_locking_types.h"
#include "opts.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 trace_and_count(_c, _name, ...) \
do { \
this_cpu_inc((_c)->counters[BCH_COUNTER_##_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")
#define bch_info(c, fmt, ...) \
printk(KERN_INFO bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_notice(c, fmt, ...) \
printk(KERN_NOTICE bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_warn(c, fmt, ...) \
printk(KERN_WARNING bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_warn_ratelimited(c, fmt, ...) \
printk_ratelimited(KERN_WARNING bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_err(c, fmt, ...) \
printk(KERN_ERR bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_err_dev(ca, fmt, ...) \
printk(KERN_ERR bch2_fmt_dev(ca, fmt), ##__VA_ARGS__)
#define bch_err_dev_offset(ca, _offset, fmt, ...) \
printk(KERN_ERR bch2_fmt_dev_offset(ca, _offset, fmt), ##__VA_ARGS__)
#define bch_err_inum(c, _inum, fmt, ...) \
printk(KERN_ERR bch2_fmt_inum(c, _inum, fmt), ##__VA_ARGS__)
#define bch_err_inum_offset(c, _inum, _offset, fmt, ...) \
printk(KERN_ERR bch2_fmt_inum_offset(c, _inum, _offset, fmt), ##__VA_ARGS__)
#define bch_err_ratelimited(c, fmt, ...) \
printk_ratelimited(KERN_ERR bch2_fmt(c, fmt), ##__VA_ARGS__)
#define bch_err_dev_ratelimited(ca, fmt, ...) \
printk_ratelimited(KERN_ERR bch2_fmt_dev(ca, fmt), ##__VA_ARGS__)
#define bch_err_dev_offset_ratelimited(ca, _offset, fmt, ...) \
printk_ratelimited(KERN_ERR bch2_fmt_dev_offset(ca, _offset, fmt), ##__VA_ARGS__)
#define bch_err_inum_ratelimited(c, _inum, fmt, ...) \
printk_ratelimited(KERN_ERR bch2_fmt_inum(c, _inum, fmt), ##__VA_ARGS__)
#define bch_err_inum_offset_ratelimited(c, _inum, _offset, fmt, ...) \
printk_ratelimited(KERN_ERR bch2_fmt_inum_offset(c, _inum, _offset, fmt), ##__VA_ARGS__)
#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_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 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_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) \
x(blocked_allocate) \
x(blocked_allocate_open_bucket) \
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_types.h"
#include "btree_write_buffer_types.h"
#include "buckets_types.h"
#include "buckets_waiting_for_journal_types.h"
#include "clock_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 "subvolume_types.h"
#include "super_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;
enum gc_phase {
GC_PHASE_NOT_RUNNING,
GC_PHASE_START,
GC_PHASE_SB,
GC_PHASE_BTREE_stripes,
GC_PHASE_BTREE_extents,
GC_PHASE_BTREE_inodes,
GC_PHASE_BTREE_dirents,
GC_PHASE_BTREE_xattrs,
GC_PHASE_BTREE_alloc,
GC_PHASE_BTREE_quotas,
GC_PHASE_BTREE_reflink,
GC_PHASE_BTREE_subvolumes,
GC_PHASE_BTREE_snapshots,
GC_PHASE_BTREE_lru,
GC_PHASE_BTREE_freespace,
GC_PHASE_BTREE_need_discard,
GC_PHASE_BTREE_backpointers,
GC_PHASE_BTREE_bucket_gens,
GC_PHASE_PENDING_DELETE,
};
struct gc_pos {
enum gc_phase phase;
struct bpos pos;
unsigned level;
};
struct reflink_gc {
u64 offset;
u32 size;
u32 refcount;
};
typedef GENRADIX(struct reflink_gc) reflink_gc_table;
struct io_count {
u64 sectors[2][BCH_DATA_NR];
};
struct bch_dev {
struct kobject kobj;
struct percpu_ref ref;
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;
__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;
/* biosets used in cloned bios for writing multiple replicas */
struct bio_set replica_set;
/*
* Buckets:
* Per-bucket arrays are protected by c->mark_lock, bucket_lock and
* gc_lock, for device resize - holding any is sufficient for access:
* Or rcu_read_lock(), but only for ptr_stale():
*/
struct bucket_array __rcu *buckets_gc;
struct bucket_gens __rcu *bucket_gens;
u8 *oldest_gen;
unsigned long *buckets_nouse;
struct rw_semaphore bucket_lock;
struct bch_dev_usage *usage_base;
struct bch_dev_usage __percpu *usage[JOURNAL_BUF_NR];
struct bch_dev_usage __percpu *usage_gc;
/* Allocator: */
u64 new_fs_bucket_idx;
u64 alloc_cursor;
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;
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 io_latency[2];
#define CONGESTED_MAX 1024
atomic_t congested;
u64 congested_last;
struct io_count __percpu *io_done;
};
enum {
/* startup: */
BCH_FS_STARTED,
BCH_FS_MAY_GO_RW,
BCH_FS_RW,
BCH_FS_WAS_RW,
/* shutdown: */
BCH_FS_STOPPING,
BCH_FS_EMERGENCY_RO,
BCH_FS_GOING_RO,
BCH_FS_WRITE_DISABLE_COMPLETE,
BCH_FS_CLEAN_SHUTDOWN,
/* fsck passes: */
BCH_FS_TOPOLOGY_REPAIR_DONE,
BCH_FS_INITIAL_GC_DONE, /* kill when we enumerate fsck passes */
BCH_FS_CHECK_ALLOC_DONE,
BCH_FS_CHECK_LRUS_DONE,
BCH_FS_CHECK_BACKPOINTERS_DONE,
BCH_FS_CHECK_ALLOC_TO_LRU_REFS_DONE,
BCH_FS_FSCK_DONE,
BCH_FS_INITIAL_GC_UNFIXED, /* kill when we enumerate fsck errors */
BCH_FS_NEED_ANOTHER_GC,
BCH_FS_HAVE_DELETED_SNAPSHOTS,
/* errors: */
BCH_FS_ERROR,
BCH_FS_TOPOLOGY_ERROR,
BCH_FS_ERRORS_FIXED,
BCH_FS_ERRORS_NOT_FIXED,
};
struct btree_debug {
unsigned id;
};
#define BCH_TRANSACTIONS_NR 128
struct btree_transaction_stats {
struct bch2_time_stats lock_hold_times;
struct mutex lock;
unsigned nr_max_paths;
unsigned wb_updates_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[0];
};
struct journal_keys {
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;
} *d;
/*
* 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;
size_t nr;
size_t size;
};
struct btree_path_buf {
struct btree_path *path;
};
#define REPLICAS_DELTA_LIST_MAX (1U << 16)
struct snapshot_t {
u32 parent;
u32 children[2];
u32 subvol; /* Nonzero only if a subvolume points to this node: */
u32 equiv;
};
typedef struct {
u32 subvol;
u64 inum;
} subvol_inum;
#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(discard) \
x(invalidate) \
x(delete_dead_snapshots) \
x(snapshot_delete_pagecache) \
x(sysfs)
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];
/* 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
struct work_struct read_only_work;
struct bch_dev __rcu *devs[BCH_SB_MEMBERS_MAX];
struct bch_replicas_cpu replicas;
struct bch_replicas_cpu replicas_gc;
struct mutex replicas_gc_lock;
mempool_t replicas_delta_pool;
struct journal_entry_res btree_root_journal_res;
struct journal_entry_res replicas_journal_res;
struct journal_entry_res clock_journal_res;
struct journal_entry_res dev_usage_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;
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;
} 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: */
GENRADIX(struct snapshot_t) snapshots;
struct bch_snapshot_table __rcu *snapshot_table;
struct mutex snapshot_table_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 *io_complete_wq;
struct btree_root btree_roots[BTREE_ID_NR];
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 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 mutex btree_trans_lock;
struct list_head btree_trans_list;
mempool_t btree_paths_pool;
mempool_t btree_trans_mem_pool;
struct btree_path_buf __percpu *btree_paths_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];
u64 capacity; /* 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 *usage_base;
struct bch_fs_usage __percpu *usage[JOURNAL_BUF_NR];
struct bch_fs_usage __percpu *usage_gc;
u64 __percpu *online_reserved;
/* single element mempool: */
struct mutex usage_scratch_lock;
struct bch_fs_usage_online *usage_scratch;
struct io_clock io_clock[2];
/* JOURNAL SEQ BLACKLIST */
struct journal_seq_blacklist_table *
journal_seq_blacklist_table;
struct work_struct journal_seq_blacklist_gc_work;
/* ALLOCATOR */
spinlock_t freelist_lock;
struct closure_waitlist freelist_wait;
u64 blocked_allocate;
u64 blocked_allocate_open_bucket;
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;
struct work_struct discard_work;
struct work_struct invalidate_work;
/* GARBAGE COLLECTION */
struct task_struct *gc_thread;
atomic_t kick_gc;
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 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;
ZSTD_parameters zstd_params;
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;
struct list_head data_progress_list;
struct mutex data_progress_lock;
/* REBALANCE */
struct bch_fs_rebalance rebalance;
/* COPYGC */
struct task_struct *copygc_thread;
struct write_point copygc_write_point;
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 */
u64 reflink_hint;
reflink_gc_table reflink_gc_table;
size_t reflink_gc_nr;
/* fs.c */
struct list_head vfs_inodes_list;
struct mutex vfs_inodes_lock;
/* 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;
/* ERRORS */
struct list_head fsck_errors;
struct mutex fsck_error_lock;
bool fsck_alloc_err;
/* QUOTAS */
struct bch_memquota_type quotas[QTYP_NR];
/* 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;
u64 last_bucket_seq_cleanup;
u64 counters_on_mount[BCH_COUNTER_NR];
u64 __percpu *counters;
unsigned btree_gc_periodic:1;
unsigned copy_gc_enabled:1;
bool promote_whole_extents;
struct bch2_time_stats times[BCH_TIME_STAT_NR];
struct btree_transaction_stats btree_transaction_stats[BCH_TRANSACTIONS_NR];
};
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_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 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 size_t btree_sectors(const struct bch_fs *c)
{
return c->opts.btree_node_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;
s32 rem;
time += c->sb.time_base_lo;
t.tv_sec = div_s64_rem(time, c->sb.time_units_per_sec, &rem);
t.tv_nsec = rem * 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 bool bch2_dev_exists2(const struct bch_fs *c, unsigned dev)
{
return dev < c->sb.nr_devices && c->devs[dev];
}
#define BKEY_PADDED_ONSTACK(key, pad) \
struct { struct bkey_i key; __u64 key ## _pad[pad]; }
#endif /* _BCACHEFS_H */
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