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ctree.h
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ctree.h
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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#ifndef BTRFS_CTREE_H
#define BTRFS_CTREE_H
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/highmem.h>
#include <linux/fs.h>
#include <linux/rwsem.h>
#include <linux/semaphore.h>
#include <linux/completion.h>
#include <linux/backing-dev.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <trace/events/btrfs.h>
#include <asm/unaligned.h>
#include <linux/pagemap.h>
#include <linux/btrfs.h>
#include <linux/btrfs_tree.h>
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/sizes.h>
#include <linux/dynamic_debug.h>
#include <linux/refcount.h>
#include <linux/crc32c.h>
#include <linux/iomap.h>
#include "extent-io-tree.h"
#include "extent_io.h"
#include "extent_map.h"
#include "async-thread.h"
#include "block-rsv.h"
#include "locking.h"
struct btrfs_trans_handle;
struct btrfs_transaction;
struct btrfs_pending_snapshot;
struct btrfs_delayed_ref_root;
struct btrfs_space_info;
struct btrfs_block_group;
extern struct kmem_cache *btrfs_trans_handle_cachep;
extern struct kmem_cache *btrfs_bit_radix_cachep;
extern struct kmem_cache *btrfs_path_cachep;
extern struct kmem_cache *btrfs_free_space_cachep;
extern struct kmem_cache *btrfs_free_space_bitmap_cachep;
struct btrfs_ordered_sum;
struct btrfs_ref;
struct btrfs_bio;
struct btrfs_ioctl_encoded_io_args;
#define BTRFS_MAGIC 0x4D5F53665248425FULL /* ascii _BHRfS_M, no null */
/*
* Maximum number of mirrors that can be available for all profiles counting
* the target device of dev-replace as one. During an active device replace
* procedure, the target device of the copy operation is a mirror for the
* filesystem data as well that can be used to read data in order to repair
* read errors on other disks.
*
* Current value is derived from RAID1C4 with 4 copies.
*/
#define BTRFS_MAX_MIRRORS (4 + 1)
#define BTRFS_MAX_LEVEL 8
#define BTRFS_OLDEST_GENERATION 0ULL
/*
* we can actually store much bigger names, but lets not confuse the rest
* of linux
*/
#define BTRFS_NAME_LEN 255
/*
* Theoretical limit is larger, but we keep this down to a sane
* value. That should limit greatly the possibility of collisions on
* inode ref items.
*/
#define BTRFS_LINK_MAX 65535U
#define BTRFS_EMPTY_DIR_SIZE 0
/* ioprio of readahead is set to idle */
#define BTRFS_IOPRIO_READA (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0))
#define BTRFS_DIRTY_METADATA_THRESH SZ_32M
/*
* Use large batch size to reduce overhead of metadata updates. On the reader
* side, we only read it when we are close to ENOSPC and the read overhead is
* mostly related to the number of CPUs, so it is OK to use arbitrary large
* value here.
*/
#define BTRFS_TOTAL_BYTES_PINNED_BATCH SZ_128M
#define BTRFS_MAX_EXTENT_SIZE SZ_128M
/*
* Deltas are an effective way to populate global statistics. Give macro names
* to make it clear what we're doing. An example is discard_extents in
* btrfs_free_space_ctl.
*/
#define BTRFS_STAT_NR_ENTRIES 2
#define BTRFS_STAT_CURR 0
#define BTRFS_STAT_PREV 1
/*
* Count how many BTRFS_MAX_EXTENT_SIZE cover the @size
*/
static inline u32 count_max_extents(u64 size)
{
return div_u64(size + BTRFS_MAX_EXTENT_SIZE - 1, BTRFS_MAX_EXTENT_SIZE);
}
static inline unsigned long btrfs_chunk_item_size(int num_stripes)
{
BUG_ON(num_stripes == 0);
return sizeof(struct btrfs_chunk) +
sizeof(struct btrfs_stripe) * (num_stripes - 1);
}
/*
* Runtime (in-memory) states of filesystem
*/
enum {
/* Global indicator of serious filesystem errors */
BTRFS_FS_STATE_ERROR,
/*
* Filesystem is being remounted, allow to skip some operations, like
* defrag
*/
BTRFS_FS_STATE_REMOUNTING,
/* Filesystem in RO mode */
BTRFS_FS_STATE_RO,
/* Track if a transaction abort has been reported on this filesystem */
BTRFS_FS_STATE_TRANS_ABORTED,
/*
* Bio operations should be blocked on this filesystem because a source
* or target device is being destroyed as part of a device replace
*/
BTRFS_FS_STATE_DEV_REPLACING,
/* The btrfs_fs_info created for self-tests */
BTRFS_FS_STATE_DUMMY_FS_INFO,
BTRFS_FS_STATE_NO_CSUMS,
/* Indicates there was an error cleaning up a log tree. */
BTRFS_FS_STATE_LOG_CLEANUP_ERROR,
BTRFS_FS_STATE_COUNT
};
#define BTRFS_BACKREF_REV_MAX 256
#define BTRFS_BACKREF_REV_SHIFT 56
#define BTRFS_BACKREF_REV_MASK (((u64)BTRFS_BACKREF_REV_MAX - 1) << \
BTRFS_BACKREF_REV_SHIFT)
#define BTRFS_OLD_BACKREF_REV 0
#define BTRFS_MIXED_BACKREF_REV 1
/*
* every tree block (leaf or node) starts with this header.
*/
struct btrfs_header {
/* these first four must match the super block */
u8 csum[BTRFS_CSUM_SIZE];
u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
__le64 bytenr; /* which block this node is supposed to live in */
__le64 flags;
/* allowed to be different from the super from here on down */
u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
__le64 generation;
__le64 owner;
__le32 nritems;
u8 level;
} __attribute__ ((__packed__));
/*
* this is a very generous portion of the super block, giving us
* room to translate 14 chunks with 3 stripes each.
*/
#define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048
/*
* just in case we somehow lose the roots and are not able to mount,
* we store an array of the roots from previous transactions
* in the super.
*/
#define BTRFS_NUM_BACKUP_ROOTS 4
struct btrfs_root_backup {
__le64 tree_root;
__le64 tree_root_gen;
__le64 chunk_root;
__le64 chunk_root_gen;
__le64 extent_root;
__le64 extent_root_gen;
__le64 fs_root;
__le64 fs_root_gen;
__le64 dev_root;
__le64 dev_root_gen;
__le64 csum_root;
__le64 csum_root_gen;
__le64 total_bytes;
__le64 bytes_used;
__le64 num_devices;
/* future */
__le64 unused_64[4];
u8 tree_root_level;
u8 chunk_root_level;
u8 extent_root_level;
u8 fs_root_level;
u8 dev_root_level;
u8 csum_root_level;
/* future and to align */
u8 unused_8[10];
} __attribute__ ((__packed__));
#define BTRFS_SUPER_INFO_OFFSET SZ_64K
#define BTRFS_SUPER_INFO_SIZE 4096
/*
* The reserved space at the beginning of each device.
* It covers the primary super block and leaves space for potential use by other
* tools like bootloaders or to lower potential damage of accidental overwrite.
*/
#define BTRFS_DEVICE_RANGE_RESERVED (SZ_1M)
/*
* the super block basically lists the main trees of the FS
* it currently lacks any block count etc etc
*/
struct btrfs_super_block {
/* the first 4 fields must match struct btrfs_header */
u8 csum[BTRFS_CSUM_SIZE];
/* FS specific UUID, visible to user */
u8 fsid[BTRFS_FSID_SIZE];
__le64 bytenr; /* this block number */
__le64 flags;
/* allowed to be different from the btrfs_header from here own down */
__le64 magic;
__le64 generation;
__le64 root;
__le64 chunk_root;
__le64 log_root;
/*
* This member has never been utilized since the very beginning, thus
* it's always 0 regardless of kernel version. We always use
* generation + 1 to read log tree root. So here we mark it deprecated.
*/
__le64 __unused_log_root_transid;
__le64 total_bytes;
__le64 bytes_used;
__le64 root_dir_objectid;
__le64 num_devices;
__le32 sectorsize;
__le32 nodesize;
__le32 __unused_leafsize;
__le32 stripesize;
__le32 sys_chunk_array_size;
__le64 chunk_root_generation;
__le64 compat_flags;
__le64 compat_ro_flags;
__le64 incompat_flags;
__le16 csum_type;
u8 root_level;
u8 chunk_root_level;
u8 log_root_level;
struct btrfs_dev_item dev_item;
char label[BTRFS_LABEL_SIZE];
__le64 cache_generation;
__le64 uuid_tree_generation;
/* the UUID written into btree blocks */
u8 metadata_uuid[BTRFS_FSID_SIZE];
/* Extent tree v2 */
__le64 block_group_root;
__le64 block_group_root_generation;
u8 block_group_root_level;
/* future expansion */
u8 reserved8[7];
__le64 reserved[25];
u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
/* Padded to 4096 bytes */
u8 padding[565];
} __attribute__ ((__packed__));
static_assert(sizeof(struct btrfs_super_block) == BTRFS_SUPER_INFO_SIZE);
/*
* Compat flags that we support. If any incompat flags are set other than the
* ones specified below then we will fail to mount
*/
#define BTRFS_FEATURE_COMPAT_SUPP 0ULL
#define BTRFS_FEATURE_COMPAT_SAFE_SET 0ULL
#define BTRFS_FEATURE_COMPAT_SAFE_CLEAR 0ULL
#define BTRFS_FEATURE_COMPAT_RO_SUPP \
(BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE | \
BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID | \
BTRFS_FEATURE_COMPAT_RO_VERITY)
#define BTRFS_FEATURE_COMPAT_RO_SAFE_SET 0ULL
#define BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR 0ULL
#ifdef CONFIG_BTRFS_DEBUG
/*
* Extent tree v2 supported only with CONFIG_BTRFS_DEBUG
*/
#define BTRFS_FEATURE_INCOMPAT_SUPP \
(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF | \
BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL | \
BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS | \
BTRFS_FEATURE_INCOMPAT_BIG_METADATA | \
BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO | \
BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD | \
BTRFS_FEATURE_INCOMPAT_RAID56 | \
BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF | \
BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA | \
BTRFS_FEATURE_INCOMPAT_NO_HOLES | \
BTRFS_FEATURE_INCOMPAT_METADATA_UUID | \
BTRFS_FEATURE_INCOMPAT_RAID1C34 | \
BTRFS_FEATURE_INCOMPAT_ZONED | \
BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2)
#else
#define BTRFS_FEATURE_INCOMPAT_SUPP \
(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF | \
BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL | \
BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS | \
BTRFS_FEATURE_INCOMPAT_BIG_METADATA | \
BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO | \
BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD | \
BTRFS_FEATURE_INCOMPAT_RAID56 | \
BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF | \
BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA | \
BTRFS_FEATURE_INCOMPAT_NO_HOLES | \
BTRFS_FEATURE_INCOMPAT_METADATA_UUID | \
BTRFS_FEATURE_INCOMPAT_RAID1C34 | \
BTRFS_FEATURE_INCOMPAT_ZONED)
#endif
#define BTRFS_FEATURE_INCOMPAT_SAFE_SET \
(BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
#define BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR 0ULL
/*
* A leaf is full of items. offset and size tell us where to find
* the item in the leaf (relative to the start of the data area)
*/
struct btrfs_item {
struct btrfs_disk_key key;
__le32 offset;
__le32 size;
} __attribute__ ((__packed__));
/*
* leaves have an item area and a data area:
* [item0, item1....itemN] [free space] [dataN...data1, data0]
*
* The data is separate from the items to get the keys closer together
* during searches.
*/
struct btrfs_leaf {
struct btrfs_header header;
struct btrfs_item items[];
} __attribute__ ((__packed__));
/*
* all non-leaf blocks are nodes, they hold only keys and pointers to
* other blocks
*/
struct btrfs_key_ptr {
struct btrfs_disk_key key;
__le64 blockptr;
__le64 generation;
} __attribute__ ((__packed__));
struct btrfs_node {
struct btrfs_header header;
struct btrfs_key_ptr ptrs[];
} __attribute__ ((__packed__));
/* Read ahead values for struct btrfs_path.reada */
enum {
READA_NONE,
READA_BACK,
READA_FORWARD,
/*
* Similar to READA_FORWARD but unlike it:
*
* 1) It will trigger readahead even for leaves that are not close to
* each other on disk;
* 2) It also triggers readahead for nodes;
* 3) During a search, even when a node or leaf is already in memory, it
* will still trigger readahead for other nodes and leaves that follow
* it.
*
* This is meant to be used only when we know we are iterating over the
* entire tree or a very large part of it.
*/
READA_FORWARD_ALWAYS,
};
/*
* btrfs_paths remember the path taken from the root down to the leaf.
* level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
* to any other levels that are present.
*
* The slots array records the index of the item or block pointer
* used while walking the tree.
*/
struct btrfs_path {
struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
int slots[BTRFS_MAX_LEVEL];
/* if there is real range locking, this locks field will change */
u8 locks[BTRFS_MAX_LEVEL];
u8 reada;
/* keep some upper locks as we walk down */
u8 lowest_level;
/*
* set by btrfs_split_item, tells search_slot to keep all locks
* and to force calls to keep space in the nodes
*/
unsigned int search_for_split:1;
unsigned int keep_locks:1;
unsigned int skip_locking:1;
unsigned int search_commit_root:1;
unsigned int need_commit_sem:1;
unsigned int skip_release_on_error:1;
/*
* Indicate that new item (btrfs_search_slot) is extending already
* existing item and ins_len contains only the data size and not item
* header (ie. sizeof(struct btrfs_item) is not included).
*/
unsigned int search_for_extension:1;
};
#define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r->fs_info) >> 4) - \
sizeof(struct btrfs_item))
struct btrfs_dev_replace {
u64 replace_state; /* see #define above */
time64_t time_started; /* seconds since 1-Jan-1970 */
time64_t time_stopped; /* seconds since 1-Jan-1970 */
atomic64_t num_write_errors;
atomic64_t num_uncorrectable_read_errors;
u64 cursor_left;
u64 committed_cursor_left;
u64 cursor_left_last_write_of_item;
u64 cursor_right;
u64 cont_reading_from_srcdev_mode; /* see #define above */
int is_valid;
int item_needs_writeback;
struct btrfs_device *srcdev;
struct btrfs_device *tgtdev;
struct mutex lock_finishing_cancel_unmount;
struct rw_semaphore rwsem;
struct btrfs_scrub_progress scrub_progress;
struct percpu_counter bio_counter;
wait_queue_head_t replace_wait;
};
/*
* free clusters are used to claim free space in relatively large chunks,
* allowing us to do less seeky writes. They are used for all metadata
* allocations. In ssd_spread mode they are also used for data allocations.
*/
struct btrfs_free_cluster {
spinlock_t lock;
spinlock_t refill_lock;
struct rb_root root;
/* largest extent in this cluster */
u64 max_size;
/* first extent starting offset */
u64 window_start;
/* We did a full search and couldn't create a cluster */
bool fragmented;
struct btrfs_block_group *block_group;
/*
* when a cluster is allocated from a block group, we put the
* cluster onto a list in the block group so that it can
* be freed before the block group is freed.
*/
struct list_head block_group_list;
};
enum btrfs_caching_type {
BTRFS_CACHE_NO,
BTRFS_CACHE_STARTED,
BTRFS_CACHE_FAST,
BTRFS_CACHE_FINISHED,
BTRFS_CACHE_ERROR,
};
/*
* Tree to record all locked full stripes of a RAID5/6 block group
*/
struct btrfs_full_stripe_locks_tree {
struct rb_root root;
struct mutex lock;
};
/* Discard control. */
/*
* Async discard uses multiple lists to differentiate the discard filter
* parameters. Index 0 is for completely free block groups where we need to
* ensure the entire block group is trimmed without being lossy. Indices
* afterwards represent monotonically decreasing discard filter sizes to
* prioritize what should be discarded next.
*/
#define BTRFS_NR_DISCARD_LISTS 3
#define BTRFS_DISCARD_INDEX_UNUSED 0
#define BTRFS_DISCARD_INDEX_START 1
struct btrfs_discard_ctl {
struct workqueue_struct *discard_workers;
struct delayed_work work;
spinlock_t lock;
struct btrfs_block_group *block_group;
struct list_head discard_list[BTRFS_NR_DISCARD_LISTS];
u64 prev_discard;
u64 prev_discard_time;
atomic_t discardable_extents;
atomic64_t discardable_bytes;
u64 max_discard_size;
u64 delay_ms;
u32 iops_limit;
u32 kbps_limit;
u64 discard_extent_bytes;
u64 discard_bitmap_bytes;
atomic64_t discard_bytes_saved;
};
void btrfs_init_async_reclaim_work(struct btrfs_fs_info *fs_info);
/* fs_info */
struct reloc_control;
struct btrfs_device;
struct btrfs_fs_devices;
struct btrfs_balance_control;
struct btrfs_delayed_root;
/*
* Block group or device which contains an active swapfile. Used for preventing
* unsafe operations while a swapfile is active.
*
* These are sorted on (ptr, inode) (note that a block group or device can
* contain more than one swapfile). We compare the pointer values because we
* don't actually care what the object is, we just need a quick check whether
* the object exists in the rbtree.
*/
struct btrfs_swapfile_pin {
struct rb_node node;
void *ptr;
struct inode *inode;
/*
* If true, ptr points to a struct btrfs_block_group. Otherwise, ptr
* points to a struct btrfs_device.
*/
bool is_block_group;
/*
* Only used when 'is_block_group' is true and it is the number of
* extents used by a swapfile for this block group ('ptr' field).
*/
int bg_extent_count;
};
bool btrfs_pinned_by_swapfile(struct btrfs_fs_info *fs_info, void *ptr);
enum {
BTRFS_FS_CLOSING_START,
BTRFS_FS_CLOSING_DONE,
BTRFS_FS_LOG_RECOVERING,
BTRFS_FS_OPEN,
BTRFS_FS_QUOTA_ENABLED,
BTRFS_FS_UPDATE_UUID_TREE_GEN,
BTRFS_FS_CREATING_FREE_SPACE_TREE,
BTRFS_FS_BTREE_ERR,
BTRFS_FS_LOG1_ERR,
BTRFS_FS_LOG2_ERR,
BTRFS_FS_QUOTA_OVERRIDE,
/* Used to record internally whether fs has been frozen */
BTRFS_FS_FROZEN,
/*
* Indicate that balance has been set up from the ioctl and is in the
* main phase. The fs_info::balance_ctl is initialized.
*/
BTRFS_FS_BALANCE_RUNNING,
/*
* Indicate that relocation of a chunk has started, it's set per chunk
* and is toggled between chunks.
*/
BTRFS_FS_RELOC_RUNNING,
/* Indicate that the cleaner thread is awake and doing something. */
BTRFS_FS_CLEANER_RUNNING,
/*
* The checksumming has an optimized version and is considered fast,
* so we don't need to offload checksums to workqueues.
*/
BTRFS_FS_CSUM_IMPL_FAST,
/* Indicate that the discard workqueue can service discards. */
BTRFS_FS_DISCARD_RUNNING,
/* Indicate that we need to cleanup space cache v1 */
BTRFS_FS_CLEANUP_SPACE_CACHE_V1,
/* Indicate that we can't trust the free space tree for caching yet */
BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED,
/* Indicate whether there are any tree modification log users */
BTRFS_FS_TREE_MOD_LOG_USERS,
/* Indicate that we want the transaction kthread to commit right now. */
BTRFS_FS_COMMIT_TRANS,
/* Indicate we have half completed snapshot deletions pending. */
BTRFS_FS_UNFINISHED_DROPS,
#if BITS_PER_LONG == 32
/* Indicate if we have error/warn message printed on 32bit systems */
BTRFS_FS_32BIT_ERROR,
BTRFS_FS_32BIT_WARN,
#endif
};
/*
* Exclusive operations (device replace, resize, device add/remove, balance)
*/
enum btrfs_exclusive_operation {
BTRFS_EXCLOP_NONE,
BTRFS_EXCLOP_BALANCE_PAUSED,
BTRFS_EXCLOP_BALANCE,
BTRFS_EXCLOP_DEV_ADD,
BTRFS_EXCLOP_DEV_REMOVE,
BTRFS_EXCLOP_DEV_REPLACE,
BTRFS_EXCLOP_RESIZE,
BTRFS_EXCLOP_SWAP_ACTIVATE,
};
/* Store data about transaction commits, exported via sysfs. */
struct btrfs_commit_stats {
/* Total number of commits */
u64 commit_count;
/* The maximum commit duration so far in ns */
u64 max_commit_dur;
/* The last commit duration in ns */
u64 last_commit_dur;
/* The total commit duration in ns */
u64 total_commit_dur;
};
struct btrfs_fs_info {
u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
unsigned long flags;
struct btrfs_root *tree_root;
struct btrfs_root *chunk_root;
struct btrfs_root *dev_root;
struct btrfs_root *fs_root;
struct btrfs_root *quota_root;
struct btrfs_root *uuid_root;
struct btrfs_root *data_reloc_root;
struct btrfs_root *block_group_root;
/* the log root tree is a directory of all the other log roots */
struct btrfs_root *log_root_tree;
/* The tree that holds the global roots (csum, extent, etc) */
rwlock_t global_root_lock;
struct rb_root global_root_tree;
spinlock_t fs_roots_radix_lock;
struct radix_tree_root fs_roots_radix;
/* block group cache stuff */
rwlock_t block_group_cache_lock;
struct rb_root_cached block_group_cache_tree;
/* keep track of unallocated space */
atomic64_t free_chunk_space;
/* Track ranges which are used by log trees blocks/logged data extents */
struct extent_io_tree excluded_extents;
/* logical->physical extent mapping */
struct extent_map_tree mapping_tree;
/*
* block reservation for extent, checksum, root tree and
* delayed dir index item
*/
struct btrfs_block_rsv global_block_rsv;
/* block reservation for metadata operations */
struct btrfs_block_rsv trans_block_rsv;
/* block reservation for chunk tree */
struct btrfs_block_rsv chunk_block_rsv;
/* block reservation for delayed operations */
struct btrfs_block_rsv delayed_block_rsv;
/* block reservation for delayed refs */
struct btrfs_block_rsv delayed_refs_rsv;
struct btrfs_block_rsv empty_block_rsv;
u64 generation;
u64 last_trans_committed;
/*
* Generation of the last transaction used for block group relocation
* since the filesystem was last mounted (or 0 if none happened yet).
* Must be written and read while holding btrfs_fs_info::commit_root_sem.
*/
u64 last_reloc_trans;
u64 avg_delayed_ref_runtime;
/*
* this is updated to the current trans every time a full commit
* is required instead of the faster short fsync log commits
*/
u64 last_trans_log_full_commit;
unsigned long mount_opt;
/*
* Track requests for actions that need to be done during transaction
* commit (like for some mount options).
*/
unsigned long pending_changes;
unsigned long compress_type:4;
unsigned int compress_level;
u32 commit_interval;
/*
* It is a suggestive number, the read side is safe even it gets a
* wrong number because we will write out the data into a regular
* extent. The write side(mount/remount) is under ->s_umount lock,
* so it is also safe.
*/
u64 max_inline;
struct btrfs_transaction *running_transaction;
wait_queue_head_t transaction_throttle;
wait_queue_head_t transaction_wait;
wait_queue_head_t transaction_blocked_wait;
wait_queue_head_t async_submit_wait;
/*
* Used to protect the incompat_flags, compat_flags, compat_ro_flags
* when they are updated.
*
* Because we do not clear the flags for ever, so we needn't use
* the lock on the read side.
*
* We also needn't use the lock when we mount the fs, because
* there is no other task which will update the flag.
*/
spinlock_t super_lock;
struct btrfs_super_block *super_copy;
struct btrfs_super_block *super_for_commit;
struct super_block *sb;
struct inode *btree_inode;
struct mutex tree_log_mutex;
struct mutex transaction_kthread_mutex;
struct mutex cleaner_mutex;
struct mutex chunk_mutex;
/*
* this is taken to make sure we don't set block groups ro after
* the free space cache has been allocated on them
*/
struct mutex ro_block_group_mutex;
/* this is used during read/modify/write to make sure
* no two ios are trying to mod the same stripe at the same
* time
*/
struct btrfs_stripe_hash_table *stripe_hash_table;
/*
* this protects the ordered operations list only while we are
* processing all of the entries on it. This way we make
* sure the commit code doesn't find the list temporarily empty
* because another function happens to be doing non-waiting preflush
* before jumping into the main commit.
*/
struct mutex ordered_operations_mutex;
struct rw_semaphore commit_root_sem;
struct rw_semaphore cleanup_work_sem;
struct rw_semaphore subvol_sem;
spinlock_t trans_lock;
/*
* the reloc mutex goes with the trans lock, it is taken
* during commit to protect us from the relocation code
*/
struct mutex reloc_mutex;
struct list_head trans_list;
struct list_head dead_roots;
struct list_head caching_block_groups;
spinlock_t delayed_iput_lock;
struct list_head delayed_iputs;
atomic_t nr_delayed_iputs;
wait_queue_head_t delayed_iputs_wait;
atomic64_t tree_mod_seq;
/* this protects tree_mod_log and tree_mod_seq_list */
rwlock_t tree_mod_log_lock;
struct rb_root tree_mod_log;
struct list_head tree_mod_seq_list;
atomic_t async_delalloc_pages;
/*
* this is used to protect the following list -- ordered_roots.
*/
spinlock_t ordered_root_lock;
/*
* all fs/file tree roots in which there are data=ordered extents
* pending writeback are added into this list.
*
* these can span multiple transactions and basically include
* every dirty data page that isn't from nodatacow
*/
struct list_head ordered_roots;
struct mutex delalloc_root_mutex;
spinlock_t delalloc_root_lock;
/* all fs/file tree roots that have delalloc inodes. */
struct list_head delalloc_roots;
/*
* there is a pool of worker threads for checksumming during writes
* and a pool for checksumming after reads. This is because readers
* can run with FS locks held, and the writers may be waiting for
* those locks. We don't want ordering in the pending list to cause
* deadlocks, and so the two are serviced separately.
*
* A third pool does submit_bio to avoid deadlocking with the other
* two
*/
struct btrfs_workqueue *workers;
struct btrfs_workqueue *hipri_workers;
struct btrfs_workqueue *delalloc_workers;
struct btrfs_workqueue *flush_workers;
struct workqueue_struct *endio_workers;
struct workqueue_struct *endio_meta_workers;
struct workqueue_struct *endio_raid56_workers;
struct workqueue_struct *rmw_workers;
struct workqueue_struct *compressed_write_workers;
struct btrfs_workqueue *endio_write_workers;
struct btrfs_workqueue *endio_freespace_worker;
struct btrfs_workqueue *caching_workers;
/*
* fixup workers take dirty pages that didn't properly go through
* the cow mechanism and make them safe to write. It happens
* for the sys_munmap function call path
*/
struct btrfs_workqueue *fixup_workers;
struct btrfs_workqueue *delayed_workers;
struct task_struct *transaction_kthread;
struct task_struct *cleaner_kthread;
u32 thread_pool_size;
struct kobject *space_info_kobj;
struct kobject *qgroups_kobj;
/* used to keep from writing metadata until there is a nice batch */
struct percpu_counter dirty_metadata_bytes;
struct percpu_counter delalloc_bytes;
struct percpu_counter ordered_bytes;
s32 dirty_metadata_batch;
s32 delalloc_batch;
struct list_head dirty_cowonly_roots;
struct btrfs_fs_devices *fs_devices;
/*
* The space_info list is effectively read only after initial
* setup. It is populated at mount time and cleaned up after
* all block groups are removed. RCU is used to protect it.
*/
struct list_head space_info;
struct btrfs_space_info *data_sinfo;
struct reloc_control *reloc_ctl;
/* data_alloc_cluster is only used in ssd_spread mode */
struct btrfs_free_cluster data_alloc_cluster;
/* all metadata allocations go through this cluster */
struct btrfs_free_cluster meta_alloc_cluster;
/* auto defrag inodes go here */
spinlock_t defrag_inodes_lock;
struct rb_root defrag_inodes;
atomic_t defrag_running;
/* Used to protect avail_{data, metadata, system}_alloc_bits */
seqlock_t profiles_lock;
/*
* these three are in extended format (availability of single
* chunks is denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE bit, other
* types are denoted by corresponding BTRFS_BLOCK_GROUP_* bits)
*/
u64 avail_data_alloc_bits;
u64 avail_metadata_alloc_bits;
u64 avail_system_alloc_bits;
/* restriper state */
spinlock_t balance_lock;
struct mutex balance_mutex;
atomic_t balance_pause_req;
atomic_t balance_cancel_req;
struct btrfs_balance_control *balance_ctl;
wait_queue_head_t balance_wait_q;
/* Cancellation requests for chunk relocation */
atomic_t reloc_cancel_req;
u32 data_chunk_allocations;
u32 metadata_ratio;
void *bdev_holder;
/* private scrub information */
struct mutex scrub_lock;
atomic_t scrubs_running;
atomic_t scrub_pause_req;
atomic_t scrubs_paused;
atomic_t scrub_cancel_req;
wait_queue_head_t scrub_pause_wait;
/*
* The worker pointers are NULL iff the refcount is 0, ie. scrub is not
* running.
*/
refcount_t scrub_workers_refcnt;
struct workqueue_struct *scrub_workers;
struct workqueue_struct *scrub_wr_completion_workers;
struct workqueue_struct *scrub_parity_workers;
struct btrfs_subpage_info *subpage_info;
struct btrfs_discard_ctl discard_ctl;
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
u32 check_integrity_print_mask;
#endif
/* is qgroup tracking in a consistent state? */
u64 qgroup_flags;
/* holds configuration and tracking. Protected by qgroup_lock */
struct rb_root qgroup_tree;
spinlock_t qgroup_lock;
/*
* used to avoid frequently calling ulist_alloc()/ulist_free()
* when doing qgroup accounting, it must be protected by qgroup_lock.
*/
struct ulist *qgroup_ulist;
/*
* Protect user change for quota operations. If a transaction is needed,
* it must be started before locking this lock.
*/
struct mutex qgroup_ioctl_lock;