blob: c03c58246033bffda5bb714c6b4f900d9b2d67ee [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
* Copyright (C) 2007 Oracle. All rights reserved.
#include <linux/pagemap.h>
#include <linux/spinlock.h>
#include <linux/rbtree.h>
#include <linux/mutex.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/atomic.h>
#include <linux/xarray.h>
#include <linux/refcount.h>
#include <uapi/linux/btrfs_tree.h>
#include "locking.h"
#include "fs.h"
#include "accessors.h"
#include "extent-io-tree.h"
struct extent_buffer;
struct btrfs_block_rsv;
struct btrfs_trans_handle;
struct btrfs_block_group;
/* Read ahead values for struct btrfs_path.reada */
enum {
* 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.
* 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;
/* Stop search if any locks need to be taken (for read) */
unsigned int nowait:1;
* The state of btrfs root
enum {
* btrfs_record_root_in_trans is a multi-step process, and it can race
* with the balancing code. But the race is very small, and only the
* first time the root is added to each transaction. So IN_TRANS_SETUP
* is used to tell us when more checks are required
* Set if tree blocks of this root can be shared by other roots.
* Only subvolume trees and their reloc trees have this bit set.
* Conflicts with TRACK_DIRTY bit.
* This affects two things:
* - How balance works
* For shareable roots, we need to use reloc tree and do path
* replacement for balance, and need various pre/post hooks for
* snapshot creation to handle them.
* While for non-shareable trees, we just simply do a tree search
* with COW.
* - How dirty roots are tracked
* For shareable roots, btrfs_record_root_in_trans() is needed to
* track them, while non-subvolume roots have TRACK_DIRTY bit, they
* don't need to set this manually.
* Reloc tree is orphan, only kept here for qgroup delayed subtree scan
* Set for the subvolume tree owning the reloc tree.
/* Mark dead root stored on device whose cleanup needs to be resumed */
/* The root has a log tree. Used for subvolume roots and the tree root. */
/* Qgroup flushing is in progress */
/* We started the orphan cleanup for this root. */
/* This root has a drop operation that was started previously. */
/* This reloc root needs to have its buffers lockdep class reset. */
* Record swapped tree blocks of a subvolume tree for delayed subtree trace
* code. For detail check comment in fs/btrfs/qgroup.c.
struct btrfs_qgroup_swapped_blocks {
spinlock_t lock;
/* RM_EMPTY_ROOT() of above blocks[] */
bool swapped;
struct rb_root blocks[BTRFS_MAX_LEVEL];
* in ram representation of the tree. extent_root is used for all allocations
* and for the extent tree extent_root root.
struct btrfs_root {
struct rb_node rb_node;
struct extent_buffer *node;
struct extent_buffer *commit_root;
struct btrfs_root *log_root;
struct btrfs_root *reloc_root;
unsigned long state;
struct btrfs_root_item root_item;
struct btrfs_key root_key;
struct btrfs_fs_info *fs_info;
struct extent_io_tree dirty_log_pages;
struct mutex objectid_mutex;
spinlock_t accounting_lock;
struct btrfs_block_rsv *block_rsv;
struct mutex log_mutex;
wait_queue_head_t log_writer_wait;
wait_queue_head_t log_commit_wait[2];
struct list_head log_ctxs[2];
/* Used only for log trees of subvolumes, not for the log root tree */
atomic_t log_writers;
atomic_t log_commit[2];
/* Used only for log trees of subvolumes, not for the log root tree */
atomic_t log_batch;
* Protected by the 'log_mutex' lock but can be read without holding
* that lock to avoid unnecessary lock contention, in which case it
* should be read using btrfs_get_root_log_transid() except if it's a
* log tree in which case it can be directly accessed. Updates to this
* field should always use btrfs_set_root_log_transid(), except for log
* trees where the field can be updated directly.
int log_transid;
/* No matter the commit succeeds or not*/
int log_transid_committed;
* Just be updated when the commit succeeds. Use
* btrfs_get_root_last_log_commit() and btrfs_set_root_last_log_commit()
* to access this field.
int last_log_commit;
pid_t log_start_pid;
u64 last_trans;
u64 free_objectid;
struct btrfs_key defrag_progress;
struct btrfs_key defrag_max;
/* The dirty list is only used by non-shareable roots */
struct list_head dirty_list;
struct list_head root_list;
spinlock_t inode_lock;
/* red-black tree that keeps track of in-memory inodes */
struct rb_root inode_tree;
* Xarray that keeps track of delayed nodes of every inode, protected
* by @inode_lock.
struct xarray delayed_nodes;
* right now this just gets used so that a root has its own devid
* for stat. It may be used for more later
dev_t anon_dev;
spinlock_t root_item_lock;
refcount_t refs;
struct mutex delalloc_mutex;
spinlock_t delalloc_lock;
* all of the inodes that have delalloc bytes. It is possible for
* this list to be empty even when there is still dirty data=ordered
* extents waiting to finish IO.
struct list_head delalloc_inodes;
struct list_head delalloc_root;
u64 nr_delalloc_inodes;
struct mutex ordered_extent_mutex;
* this is used by the balancing code to wait for all the pending
* ordered extents
spinlock_t ordered_extent_lock;
* all of the data=ordered extents pending writeback
* these can span multiple transactions and basically include
* every dirty data page that isn't from nodatacow
struct list_head ordered_extents;
struct list_head ordered_root;
u64 nr_ordered_extents;
* Not empty if this subvolume root has gone through tree block swap
* (relocation)
* Will be used by reloc_control::dirty_subvol_roots.
struct list_head reloc_dirty_list;
* Number of currently running SEND ioctls to prevent
* manipulation with the read-only status via SUBVOL_SETFLAGS
int send_in_progress;
* Number of currently running deduplication operations that have a
* destination inode belonging to this root. Protected by the lock
* root_item_lock.
int dedupe_in_progress;
/* For exclusion of snapshot creation and nocow writes */
struct btrfs_drew_lock snapshot_lock;
atomic_t snapshot_force_cow;
/* For qgroup metadata reserved space */
spinlock_t qgroup_meta_rsv_lock;
u64 qgroup_meta_rsv_pertrans;
u64 qgroup_meta_rsv_prealloc;
wait_queue_head_t qgroup_flush_wait;
/* Number of active swapfiles */
atomic_t nr_swapfiles;
/* Record pairs of swapped blocks for qgroup */
struct btrfs_qgroup_swapped_blocks swapped_blocks;
/* Used only by log trees, when logging csum items */
struct extent_io_tree log_csum_range;
/* Used in simple quotas, track root during relocation. */
u64 relocation_src_root;
u64 alloc_bytenr;
struct list_head leak_list;
static inline bool btrfs_root_readonly(const struct btrfs_root *root)
/* Byte-swap the constant at compile time, root_item::flags is LE */
return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
static inline bool btrfs_root_dead(const struct btrfs_root *root)
/* Byte-swap the constant at compile time, root_item::flags is LE */
return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
static inline u64 btrfs_root_id(const struct btrfs_root *root)
return root->root_key.objectid;
static inline int btrfs_get_root_log_transid(const struct btrfs_root *root)
return READ_ONCE(root->log_transid);
static inline void btrfs_set_root_log_transid(struct btrfs_root *root, int log_transid)
WRITE_ONCE(root->log_transid, log_transid);
static inline int btrfs_get_root_last_log_commit(const struct btrfs_root *root)
return READ_ONCE(root->last_log_commit);
static inline void btrfs_set_root_last_log_commit(struct btrfs_root *root, int commit_id)
WRITE_ONCE(root->last_log_commit, commit_id);
* Structure that conveys information about an extent that is going to replace
* all the extents in a file range.
struct btrfs_replace_extent_info {
u64 disk_offset;
u64 disk_len;
u64 data_offset;
u64 data_len;
u64 file_offset;
/* Pointer to a file extent item of type regular or prealloc. */
char *extent_buf;
* Set to true when attempting to replace a file range with a new extent
* described by this structure, set to false when attempting to clone an
* existing extent into a file range.
bool is_new_extent;
/* Indicate if we should update the inode's mtime and ctime. */
bool update_times;
/* Meaningful only if is_new_extent is true. */
int qgroup_reserved;
* Meaningful only if is_new_extent is true.
* Used to track how many extent items we have already inserted in a
* subvolume tree that refer to the extent described by this structure,
* so that we know when to create a new delayed ref or update an existing
* one.
int insertions;
/* Arguments for btrfs_drop_extents() */
struct btrfs_drop_extents_args {
/* Input parameters */
* If NULL, btrfs_drop_extents() will allocate and free its own path.
* If 'replace_extent' is true, this must not be NULL. Also the path
* is always released except if 'replace_extent' is true and
* btrfs_drop_extents() sets 'extent_inserted' to true, in which case
* the path is kept locked.
struct btrfs_path *path;
/* Start offset of the range to drop extents from */
u64 start;
/* End (exclusive, last byte + 1) of the range to drop extents from */
u64 end;
/* If true drop all the extent maps in the range */
bool drop_cache;
* If true it means we want to insert a new extent after dropping all
* the extents in the range. If this is true, the 'extent_item_size'
* parameter must be set as well and the 'extent_inserted' field will
* be set to true by btrfs_drop_extents() if it could insert the new
* extent.
* Note: when this is set to true the path must not be NULL.
bool replace_extent;
* Used if 'replace_extent' is true. Size of the file extent item to
* insert after dropping all existing extents in the range
u32 extent_item_size;
/* Output parameters */
* Set to the minimum between the input parameter 'end' and the end
* (exclusive, last byte + 1) of the last dropped extent. This is always
* set even if btrfs_drop_extents() returns an error.
u64 drop_end;
* The number of allocated bytes found in the range. This can be smaller
* than the range's length when there are holes in the range.
u64 bytes_found;
* Only set if 'replace_extent' is true. Set to true if we were able
* to insert a replacement extent after dropping all extents in the
* range, otherwise set to false by btrfs_drop_extents().
* Also, if btrfs_drop_extents() has set this to true it means it
* returned with the path locked, otherwise if it has set this to
* false it has returned with the path released.
bool extent_inserted;
struct btrfs_file_private {
void *filldir_buf;
u64 last_index;
struct extent_state *llseek_cached_state;
static inline u32 BTRFS_LEAF_DATA_SIZE(const struct btrfs_fs_info *info)
return info->nodesize - sizeof(struct btrfs_header);
static inline u32 BTRFS_MAX_ITEM_SIZE(const struct btrfs_fs_info *info)
return BTRFS_LEAF_DATA_SIZE(info) - sizeof(struct btrfs_item);
static inline u32 BTRFS_NODEPTRS_PER_BLOCK(const struct btrfs_fs_info *info)
return BTRFS_LEAF_DATA_SIZE(info) / sizeof(struct btrfs_key_ptr);
static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
return BTRFS_MAX_ITEM_SIZE(info) - sizeof(struct btrfs_dir_item);
#define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \
((bytes) >> (fs_info)->sectorsize_bits)
static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
return mapping_gfp_constraint(mapping, ~__GFP_FS);
void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end);
int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
u64 num_bytes, u64 *actual_bytes);
int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range);
/* ctree.c */
int __init btrfs_ctree_init(void);
void __cold btrfs_ctree_exit(void);
int btrfs_bin_search(struct extent_buffer *eb, int first_slot,
const struct btrfs_key *key, int *slot);
int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);
* Compare two keys, on little-endian the disk order is same as CPU order and
* we can avoid the conversion.
static inline int btrfs_comp_keys(const struct btrfs_disk_key *disk_key,
const struct btrfs_key *k2)
const struct btrfs_key *k1 = (const struct btrfs_key *)disk_key;
return btrfs_comp_cpu_keys(k1, k2);
/* Compare two keys in a memcmp fashion. */
static inline int btrfs_comp_keys(const struct btrfs_disk_key *disk,
const struct btrfs_key *k2)
struct btrfs_key k1;
btrfs_disk_key_to_cpu(&k1, disk);
return btrfs_comp_cpu_keys(&k1, k2);
int btrfs_previous_item(struct btrfs_root *root,
struct btrfs_path *path, u64 min_objectid,
int type);
int btrfs_previous_extent_item(struct btrfs_root *root,
struct btrfs_path *path, u64 min_objectid);
void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
const struct btrfs_key *new_key);
struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *key, int lowest_level,
u64 min_trans);
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
struct btrfs_path *path,
u64 min_trans);
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
int slot);
int btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret,
enum btrfs_lock_nesting nest);
int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret,
u64 search_start, u64 empty_size,
enum btrfs_lock_nesting nest);
int btrfs_copy_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer **cow_ret, u64 new_root_objectid);
bool btrfs_block_can_be_shared(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf);
int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot);
void btrfs_extend_item(struct btrfs_trans_handle *trans,
struct btrfs_path *path, u32 data_size);
void btrfs_truncate_item(struct btrfs_trans_handle *trans,
struct btrfs_path *path, u32 new_size, int from_end);
int btrfs_split_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
const struct btrfs_key *new_key,
unsigned long split_offset);
int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
const struct btrfs_key *new_key);
int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
u64 inum, u64 ioff, u8 key_type, struct btrfs_key *found_key);
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
const struct btrfs_key *key, struct btrfs_path *p,
int ins_len, int cow);
int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
struct btrfs_path *p, u64 time_seq);
int btrfs_search_slot_for_read(struct btrfs_root *root,
const struct btrfs_key *key,
struct btrfs_path *p, int find_higher,
int return_any);
void btrfs_release_path(struct btrfs_path *p);
struct btrfs_path *btrfs_alloc_path(void);
void btrfs_free_path(struct btrfs_path *p);
int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int slot, int nr);
static inline int btrfs_del_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path)
return btrfs_del_items(trans, root, path, path->slots[0], 1);
* Describes a batch of items to insert in a btree. This is used by
* btrfs_insert_empty_items().
struct btrfs_item_batch {
* Pointer to an array containing the keys of the items to insert (in
* sorted order).
const struct btrfs_key *keys;
/* Pointer to an array containing the data size for each item to insert. */
const u32 *data_sizes;
* The sum of data sizes for all items. The caller can compute this while
* setting up the data_sizes array, so it ends up being more efficient
* than having btrfs_insert_empty_items() or setup_item_for_insert()
* doing it, as it would avoid an extra loop over a potentially large
* array, and in the case of setup_item_for_insert(), we would be doing
* it while holding a write lock on a leaf and often on upper level nodes
* too, unnecessarily increasing the size of a critical section.
u32 total_data_size;
/* Size of the keys and data_sizes arrays (number of items in the batch). */
int nr;
void btrfs_setup_item_for_insert(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
const struct btrfs_key *key,
u32 data_size);
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
const struct btrfs_key *key, void *data, u32 data_size);
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
const struct btrfs_item_batch *batch);
static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
const struct btrfs_key *key,
u32 data_size)
struct btrfs_item_batch batch;
batch.keys = key;
batch.data_sizes = &data_size;
batch.total_data_size = data_size; = 1;
return btrfs_insert_empty_items(trans, root, path, &batch);
int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
u64 time_seq);
int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key,
struct btrfs_path *path);
int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key,
struct btrfs_path *path);
* Search in @root for a given @key, and store the slot found in @found_key.
* @root: The root node of the tree.
* @key: The key we are looking for.
* @found_key: Will hold the found item.
* @path: Holds the current slot/leaf.
* @iter_ret: Contains the value returned from btrfs_search_slot or
* btrfs_get_next_valid_item, whichever was executed last.
* The @iter_ret is an output variable that will contain the return value of
* btrfs_search_slot, if it encountered an error, or the value returned from
* btrfs_get_next_valid_item otherwise. That return value can be 0, if a valid
* slot was found, 1 if there were no more leaves, and <0 if there was an error.
* It's recommended to use a separate variable for iter_ret and then use it to
* set the function return value so there's no confusion of the 0/1/errno
* values stemming from btrfs_search_slot.
#define btrfs_for_each_slot(root, key, found_key, path, iter_ret) \
for (iter_ret = btrfs_search_slot(NULL, (root), (key), (path), 0, 0); \
(iter_ret) >= 0 && \
(iter_ret = btrfs_get_next_valid_item((root), (found_key), (path))) == 0; \
(path)->slots[0]++ \
int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *path, u64 time_seq);
* Search the tree again to find a leaf with greater keys.
* Returns 0 if it found something or 1 if there are no greater leaves.
* Returns < 0 on error.
static inline int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
return btrfs_next_old_leaf(root, path, 0);
static inline int btrfs_next_item(struct btrfs_root *root, struct btrfs_path *p)
return btrfs_next_old_item(root, p, 0);
int btrfs_leaf_free_space(const struct extent_buffer *leaf);
static inline int is_fstree(u64 rootid)
if (rootid == BTRFS_FS_TREE_OBJECTID ||
((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID &&
return 1;
return 0;
static inline bool btrfs_is_data_reloc_root(const struct btrfs_root *root)
return root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID;
u16 btrfs_csum_type_size(u16 type);
int btrfs_super_csum_size(const struct btrfs_super_block *s);
const char *btrfs_super_csum_name(u16 csum_type);
const char *btrfs_super_csum_driver(u16 csum_type);
size_t __attribute_const__ btrfs_get_num_csums(void);
* We use page status Private2 to indicate there is an ordered extent with
* unfinished IO.
* Rename the Private2 accessors to Ordered, to improve readability.
#define PageOrdered(page) PagePrivate2(page)
#define SetPageOrdered(page) SetPagePrivate2(page)
#define ClearPageOrdered(page) ClearPagePrivate2(page)
#define folio_test_ordered(folio) folio_test_private_2(folio)
#define folio_set_ordered(folio) folio_set_private_2(folio)
#define folio_clear_ordered(folio) folio_clear_private_2(folio)