/* 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;
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
*/ unsignedint search_for_split:1; /* Keep some upper locks as we walk down. */ unsignedint keep_locks:1; unsignedint skip_locking:1; unsignedint search_commit_root:1; unsignedint need_commit_sem:1; unsignedint 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).
*/ unsignedint search_for_extension:1; /* Stop search if any locks need to be taken (for read) */ unsignedint 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
*/
BTRFS_ROOT_IN_TRANS_SETUP,
/* * 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.
*/
BTRFS_ROOT_SHAREABLE,
BTRFS_ROOT_TRACK_DIRTY,
BTRFS_ROOT_IN_RADIX,
BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
BTRFS_ROOT_DEFRAG_RUNNING,
BTRFS_ROOT_FORCE_COW,
BTRFS_ROOT_MULTI_LOG_TASKS,
BTRFS_ROOT_DIRTY,
BTRFS_ROOT_DELETING,
/* * Reloc tree is orphan, only kept here for qgroup delayed subtree scan * * Set for the subvolume tree owning the reloc tree.
*/
BTRFS_ROOT_DEAD_RELOC_TREE, /* Mark dead root stored on device whose cleanup needs to be resumed */
BTRFS_ROOT_DEAD_TREE, /* The root has a log tree. Used for subvolume roots and the tree root. */
BTRFS_ROOT_HAS_LOG_TREE, /* Qgroup flushing is in progress */
BTRFS_ROOT_QGROUP_FLUSHING, /* We started the orphan cleanup for this root. */
BTRFS_ROOT_ORPHAN_CLEANUP, /* This root has a drop operation that was started previously. */
BTRFS_ROOT_UNFINISHED_DROP, /* This reloc root needs to have its buffers lockdep class reset. */
BTRFS_ROOT_RESET_LOCKDEP_CLASS,
};
/* * 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 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;
/* The dirty list is only used by non-shareable roots */ struct list_head dirty_list;
struct list_head root_list;
/* Xarray that keeps track of in-memory inodes. */ struct xarray inodes;
/* Xarray that keeps track of delayed nodes of every inode. */ 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;
staticinlinebool btrfs_root_readonly(conststruct 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;
}
staticinlinebool btrfs_root_dead(conststruct 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;
}
/* * Return the generation this root started with. * * Every normal root that is created with root->root_key.offset set to it's * originating generation. If it is a snapshot it is the generation when the * snapshot was created. * * However for TREE_RELOC roots root_key.offset is the objectid of the owning * tree root. Thankfully we copy the root item of the owning tree root, which * has it's last_snapshot set to what we would have root_key.offset set to, so * return that if this is a TREE_RELOC root.
*/ staticinline u64 btrfs_root_origin_generation(conststruct btrfs_root *root)
{ if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) return btrfs_root_last_snapshot(&root->root_item); return root->root_key.offset;
}
/* * 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;
};
/* * 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;
};
int __init btrfs_ctree_init(void); void __cold btrfs_ctree_exit(void);
int btrfs_bin_search(conststruct extent_buffer *eb, int first_slot, conststruct btrfs_key *key, int *slot);
int __pure btrfs_comp_cpu_keys(conststruct btrfs_key *k1, conststruct btrfs_key *k2);
#ifdef __LITTLE_ENDIAN
/* * Compare two keys, on little-endian the disk order is same as CPU order and * we can avoid the conversion.
*/ staticinlineint btrfs_comp_keys(conststruct btrfs_disk_key *disk_key, conststruct btrfs_key *k2)
{ conststruct btrfs_key *k1 = (conststruct btrfs_key *)disk_key;
return btrfs_comp_cpu_keys(k1, k2);
}
#else
/* Compare two keys in a memcmp fashion. */ staticinlineint btrfs_comp_keys(conststruct btrfs_disk_key *disk, conststruct btrfs_key *k2)
{ struct btrfs_key k1;
btrfs_disk_key_to_cpu(&k1, disk);
return btrfs_comp_cpu_keys(&k1, k2);
}
#endif
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, conststruct btrfs_path *path, conststruct 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);
/* * 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).
*/ conststruct 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;
};
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.
*/ staticinlineint btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
{ return btrfs_next_old_leaf(root, path, 0);
}
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