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/* SPDX-License-Identifier: GPL-2.0 */
* Copyright (C) 2011 STRATO. All rights reserved.
#include <linux/btrfs.h>
#include "ulist.h"
#include "disk-io.h"
#include "extent_io.h"
struct inode_fs_paths {
struct btrfs_path *btrfs_path;
struct btrfs_root *fs_root;
struct btrfs_data_container *fspath;
typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root,
void *ctx);
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
struct btrfs_path *path, struct btrfs_key *found_key,
u64 *flags);
int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
struct btrfs_key *key, struct btrfs_extent_item *ei,
u32 item_size, u64 *out_root, u8 *out_level);
int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
u64 extent_item_objectid,
u64 extent_offset, int search_commit_root,
iterate_extent_inodes_t *iterate, void *ctx,
bool ignore_offset);
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
iterate_extent_inodes_t *iterate, void *ctx,
bool ignore_offset);
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **leafs,
const u64 *extent_item_pos, bool ignore_offset);
int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **roots,
bool skip_commit_root_sem);
char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
u32 name_len, unsigned long name_off,
struct extent_buffer *eb_in, u64 parent,
char *dest, u32 size);
struct btrfs_data_container *init_data_container(u32 total_bytes);
struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
struct btrfs_path *path);
void free_ipath(struct inode_fs_paths *ipath);
int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
u64 start_off, struct btrfs_path *path,
struct btrfs_inode_extref **ret_extref,
u64 *found_off);
int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
struct ulist *roots, struct ulist *tmp_ulist);
int __init btrfs_prelim_ref_init(void);
void __cold btrfs_prelim_ref_exit(void);
struct prelim_ref {
struct rb_node rbnode;
u64 root_id;
struct btrfs_key key_for_search;
int level;
int count;
struct extent_inode_elem *inode_list;
u64 parent;
u64 wanted_disk_byte;
* Iterate backrefs of one extent.
* Now it only supports iteration of tree block in commit root.
struct btrfs_backref_iter {
u64 bytenr;
struct btrfs_path *path;
struct btrfs_fs_info *fs_info;
struct btrfs_key cur_key;
u32 item_ptr;
u32 cur_ptr;
u32 end_ptr;
struct btrfs_backref_iter *btrfs_backref_iter_alloc(
struct btrfs_fs_info *fs_info, gfp_t gfp_flag);
static inline void btrfs_backref_iter_free(struct btrfs_backref_iter *iter)
if (!iter)
static inline struct extent_buffer *btrfs_backref_get_eb(
struct btrfs_backref_iter *iter)
if (!iter)
return NULL;
return iter->path->nodes[0];
* For metadata with EXTENT_ITEM key (non-skinny) case, the first inline data
* is btrfs_tree_block_info, without a btrfs_extent_inline_ref header.
* This helper determines if that's the case.
static inline bool btrfs_backref_has_tree_block_info(
struct btrfs_backref_iter *iter)
if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY &&
iter->cur_ptr - iter->item_ptr == sizeof(struct btrfs_extent_item))
return true;
return false;
int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr);
int btrfs_backref_iter_next(struct btrfs_backref_iter *iter);
static inline bool btrfs_backref_iter_is_inline_ref(
struct btrfs_backref_iter *iter)
if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY ||
iter->cur_key.type == BTRFS_METADATA_ITEM_KEY)
return true;
return false;
static inline void btrfs_backref_iter_release(struct btrfs_backref_iter *iter)
iter->bytenr = 0;
iter->item_ptr = 0;
iter->cur_ptr = 0;
iter->end_ptr = 0;
memset(&iter->cur_key, 0, sizeof(iter->cur_key));
* Backref cache related structures
* The whole objective of backref_cache is to build a bi-directional map
* of tree blocks (represented by backref_node) and all their parents.
* Represent a tree block in the backref cache
struct btrfs_backref_node {
struct {
struct rb_node rb_node;
u64 bytenr;
}; /* Use rb_simple_node for search/insert */
u64 new_bytenr;
/* Objectid of tree block owner, can be not uptodate */
u64 owner;
/* Link to pending, changed or detached list */
struct list_head list;
/* List of upper level edges, which link this node to its parents */
struct list_head upper;
/* List of lower level edges, which link this node to its children */
struct list_head lower;
/* NULL if this node is not tree root */
struct btrfs_root *root;
/* Extent buffer got by COWing the block */
struct extent_buffer *eb;
/* Level of the tree block */
unsigned int level:8;
/* Is the block in a non-shareable tree */
unsigned int cowonly:1;
/* 1 if no child node is in the cache */
unsigned int lowest:1;
/* Is the extent buffer locked */
unsigned int locked:1;
/* Has the block been processed */
unsigned int processed:1;
/* Have backrefs of this block been checked */
unsigned int checked:1;
* 1 if corresponding block has been COWed but some upper level block
* pointers may not point to the new location
unsigned int pending:1;
/* 1 if the backref node isn't connected to any other backref node */
unsigned int detached:1;
* For generic purpose backref cache, where we only care if it's a reloc
* root, doesn't care the source subvolid.
unsigned int is_reloc_root:1;
#define LOWER 0
#define UPPER 1
* Represent an edge connecting upper and lower backref nodes.
struct btrfs_backref_edge {
* list[LOWER] is linked to btrfs_backref_node::upper of lower level
* node, and list[UPPER] is linked to btrfs_backref_node::lower of
* upper level node.
* Also, build_backref_tree() uses list[UPPER] for pending edges, before
* linking list[UPPER] to its upper level nodes.
struct list_head list[2];
/* Two related nodes */
struct btrfs_backref_node *node[2];
struct btrfs_backref_cache {
/* Red black tree of all backref nodes in the cache */
struct rb_root rb_root;
/* For passing backref nodes to btrfs_reloc_cow_block */
struct btrfs_backref_node *path[BTRFS_MAX_LEVEL];
* List of blocks that have been COWed but some block pointers in upper
* level blocks may not reflect the new location
struct list_head pending[BTRFS_MAX_LEVEL];
/* List of backref nodes with no child node */
struct list_head leaves;
/* List of blocks that have been COWed in current transaction */
struct list_head changed;
/* List of detached backref node. */
struct list_head detached;
u64 last_trans;
int nr_nodes;
int nr_edges;
/* List of unchecked backref edges during backref cache build */
struct list_head pending_edge;
/* List of useless backref nodes during backref cache build */
struct list_head useless_node;
struct btrfs_fs_info *fs_info;
* Whether this cache is for relocation
* Reloction backref cache require more info for reloc root compared
* to generic backref cache.
unsigned int is_reloc;
void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
struct btrfs_backref_cache *cache, int is_reloc);
struct btrfs_backref_node *btrfs_backref_alloc_node(
struct btrfs_backref_cache *cache, u64 bytenr, int level);
struct btrfs_backref_edge *btrfs_backref_alloc_edge(
struct btrfs_backref_cache *cache);
#define LINK_LOWER (1 << 0)
#define LINK_UPPER (1 << 1)
static inline void btrfs_backref_link_edge(struct btrfs_backref_edge *edge,
struct btrfs_backref_node *lower,
struct btrfs_backref_node *upper,
int link_which)
ASSERT(upper && lower && upper->level == lower->level + 1);
edge->node[LOWER] = lower;
edge->node[UPPER] = upper;
if (link_which & LINK_LOWER)
list_add_tail(&edge->list[LOWER], &lower->upper);
if (link_which & LINK_UPPER)
list_add_tail(&edge->list[UPPER], &upper->lower);
static inline void btrfs_backref_free_node(struct btrfs_backref_cache *cache,
struct btrfs_backref_node *node)
if (node) {
ASSERT(node->eb == NULL);
static inline void btrfs_backref_free_edge(struct btrfs_backref_cache *cache,
struct btrfs_backref_edge *edge)
if (edge) {
static inline void btrfs_backref_unlock_node_buffer(
struct btrfs_backref_node *node)
if (node->locked) {
node->locked = 0;
static inline void btrfs_backref_drop_node_buffer(
struct btrfs_backref_node *node)
if (node->eb) {
node->eb = NULL;
* Drop the backref node from cache without cleaning up its children
* edges.
* This can only be called on node without parent edges.
* The children edges are still kept as is.
static inline void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
struct btrfs_backref_node *node)
if (!RB_EMPTY_NODE(&node->rb_node))
rb_erase(&node->rb_node, &tree->rb_root);
btrfs_backref_free_node(tree, node);
void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
struct btrfs_backref_node *node);
void btrfs_backref_release_cache(struct btrfs_backref_cache *cache);
static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
u64 bytenr, int errno)
btrfs_panic(fs_info, errno,
"Inconsistency in backref cache found at offset %llu",
int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_backref_iter *iter,
struct btrfs_key *node_key,
struct btrfs_backref_node *cur);
int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
struct btrfs_backref_node *start);
void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
struct btrfs_backref_node *node);