1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Copyright (C) 2011 STRATO. All rights reserved.
6 #ifndef BTRFS_BACKREF_H
7 #define BTRFS_BACKREF_H
9 #include <linux/btrfs.h>
12 #include "extent_io.h"
14 struct inode_fs_paths {
15 struct btrfs_path *btrfs_path;
16 struct btrfs_root *fs_root;
17 struct btrfs_data_container *fspath;
20 typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root,
23 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
24 struct btrfs_path *path, struct btrfs_key *found_key,
27 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
28 struct btrfs_key *key, struct btrfs_extent_item *ei,
29 u32 item_size, u64 *out_root, u8 *out_level);
31 int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
32 u64 extent_item_objectid,
33 u64 extent_offset, int search_commit_root,
34 iterate_extent_inodes_t *iterate, void *ctx,
37 int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
38 struct btrfs_path *path, void *ctx,
41 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
43 int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
44 struct btrfs_fs_info *fs_info, u64 bytenr,
45 u64 time_seq, struct ulist **leafs,
46 const u64 *extent_item_pos, bool ignore_offset);
47 int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
48 struct btrfs_fs_info *fs_info, u64 bytenr,
49 u64 time_seq, struct ulist **roots, bool ignore_offset);
50 char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
51 u32 name_len, unsigned long name_off,
52 struct extent_buffer *eb_in, u64 parent,
53 char *dest, u32 size);
55 struct btrfs_data_container *init_data_container(u32 total_bytes);
56 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
57 struct btrfs_path *path);
58 void free_ipath(struct inode_fs_paths *ipath);
60 int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
61 u64 start_off, struct btrfs_path *path,
62 struct btrfs_inode_extref **ret_extref,
64 int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
65 struct ulist *roots, struct ulist *tmp_ulist);
67 int __init btrfs_prelim_ref_init(void);
68 void __cold btrfs_prelim_ref_exit(void);
71 struct rb_node rbnode;
73 struct btrfs_key key_for_search;
76 struct extent_inode_elem *inode_list;
82 * Iterate backrefs of one extent.
84 * Now it only supports iteration of tree block in commit root.
86 struct btrfs_backref_iter {
88 struct btrfs_path *path;
89 struct btrfs_fs_info *fs_info;
90 struct btrfs_key cur_key;
96 struct btrfs_backref_iter *btrfs_backref_iter_alloc(
97 struct btrfs_fs_info *fs_info, gfp_t gfp_flag);
99 static inline void btrfs_backref_iter_free(struct btrfs_backref_iter *iter)
103 btrfs_free_path(iter->path);
107 static inline struct extent_buffer *btrfs_backref_get_eb(
108 struct btrfs_backref_iter *iter)
112 return iter->path->nodes[0];
116 * For metadata with EXTENT_ITEM key (non-skinny) case, the first inline data
117 * is btrfs_tree_block_info, without a btrfs_extent_inline_ref header.
119 * This helper determines if that's the case.
121 static inline bool btrfs_backref_has_tree_block_info(
122 struct btrfs_backref_iter *iter)
124 if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY &&
125 iter->cur_ptr - iter->item_ptr == sizeof(struct btrfs_extent_item))
130 int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr);
132 int btrfs_backref_iter_next(struct btrfs_backref_iter *iter);
134 static inline bool btrfs_backref_iter_is_inline_ref(
135 struct btrfs_backref_iter *iter)
137 if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY ||
138 iter->cur_key.type == BTRFS_METADATA_ITEM_KEY)
143 static inline void btrfs_backref_iter_release(struct btrfs_backref_iter *iter)
149 btrfs_release_path(iter->path);
150 memset(&iter->cur_key, 0, sizeof(iter->cur_key));
154 * Backref cache related structures
156 * The whole objective of backref_cache is to build a bi-directional map
157 * of tree blocks (represented by backref_node) and all their parents.
161 * Represent a tree block in the backref cache
163 struct btrfs_backref_node {
165 struct rb_node rb_node;
167 }; /* Use rb_simple_node for search/insert */
170 /* Objectid of tree block owner, can be not uptodate */
172 /* Link to pending, changed or detached list */
173 struct list_head list;
175 /* List of upper level edges, which link this node to its parents */
176 struct list_head upper;
177 /* List of lower level edges, which link this node to its children */
178 struct list_head lower;
180 /* NULL if this node is not tree root */
181 struct btrfs_root *root;
182 /* Extent buffer got by COWing the block */
183 struct extent_buffer *eb;
184 /* Level of the tree block */
185 unsigned int level:8;
186 /* Is the block in a non-shareable tree */
187 unsigned int cowonly:1;
188 /* 1 if no child node is in the cache */
189 unsigned int lowest:1;
190 /* Is the extent buffer locked */
191 unsigned int locked:1;
192 /* Has the block been processed */
193 unsigned int processed:1;
194 /* Have backrefs of this block been checked */
195 unsigned int checked:1;
197 * 1 if corresponding block has been COWed but some upper level block
198 * pointers may not point to the new location
200 unsigned int pending:1;
201 /* 1 if the backref node isn't connected to any other backref node */
202 unsigned int detached:1;
205 * For generic purpose backref cache, where we only care if it's a reloc
206 * root, doesn't care the source subvolid.
208 unsigned int is_reloc_root:1;
215 * Represent an edge connecting upper and lower backref nodes.
217 struct btrfs_backref_edge {
219 * list[LOWER] is linked to btrfs_backref_node::upper of lower level
220 * node, and list[UPPER] is linked to btrfs_backref_node::lower of
223 * Also, build_backref_tree() uses list[UPPER] for pending edges, before
224 * linking list[UPPER] to its upper level nodes.
226 struct list_head list[2];
228 /* Two related nodes */
229 struct btrfs_backref_node *node[2];
232 struct btrfs_backref_cache {
233 /* Red black tree of all backref nodes in the cache */
234 struct rb_root rb_root;
235 /* For passing backref nodes to btrfs_reloc_cow_block */
236 struct btrfs_backref_node *path[BTRFS_MAX_LEVEL];
238 * List of blocks that have been COWed but some block pointers in upper
239 * level blocks may not reflect the new location
241 struct list_head pending[BTRFS_MAX_LEVEL];
242 /* List of backref nodes with no child node */
243 struct list_head leaves;
244 /* List of blocks that have been COWed in current transaction */
245 struct list_head changed;
246 /* List of detached backref node. */
247 struct list_head detached;
254 /* List of unchecked backref edges during backref cache build */
255 struct list_head pending_edge;
257 /* List of useless backref nodes during backref cache build */
258 struct list_head useless_node;
260 struct btrfs_fs_info *fs_info;
263 * Whether this cache is for relocation
265 * Reloction backref cache require more info for reloc root compared
266 * to generic backref cache.
268 unsigned int is_reloc;
271 void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
272 struct btrfs_backref_cache *cache, int is_reloc);
273 struct btrfs_backref_node *btrfs_backref_alloc_node(
274 struct btrfs_backref_cache *cache, u64 bytenr, int level);
275 struct btrfs_backref_edge *btrfs_backref_alloc_edge(
276 struct btrfs_backref_cache *cache);
278 #define LINK_LOWER (1 << 0)
279 #define LINK_UPPER (1 << 1)
280 static inline void btrfs_backref_link_edge(struct btrfs_backref_edge *edge,
281 struct btrfs_backref_node *lower,
282 struct btrfs_backref_node *upper,
285 ASSERT(upper && lower && upper->level == lower->level + 1);
286 edge->node[LOWER] = lower;
287 edge->node[UPPER] = upper;
288 if (link_which & LINK_LOWER)
289 list_add_tail(&edge->list[LOWER], &lower->upper);
290 if (link_which & LINK_UPPER)
291 list_add_tail(&edge->list[UPPER], &upper->lower);
294 static inline void btrfs_backref_free_node(struct btrfs_backref_cache *cache,
295 struct btrfs_backref_node *node)
298 ASSERT(list_empty(&node->list));
299 ASSERT(list_empty(&node->lower));
300 ASSERT(node->eb == NULL);
302 btrfs_put_root(node->root);
307 static inline void btrfs_backref_free_edge(struct btrfs_backref_cache *cache,
308 struct btrfs_backref_edge *edge)
316 static inline void btrfs_backref_unlock_node_buffer(
317 struct btrfs_backref_node *node)
320 btrfs_tree_unlock(node->eb);
325 static inline void btrfs_backref_drop_node_buffer(
326 struct btrfs_backref_node *node)
329 btrfs_backref_unlock_node_buffer(node);
330 free_extent_buffer(node->eb);
336 * Drop the backref node from cache without cleaning up its children
339 * This can only be called on node without parent edges.
340 * The children edges are still kept as is.
342 static inline void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
343 struct btrfs_backref_node *node)
345 ASSERT(list_empty(&node->upper));
347 btrfs_backref_drop_node_buffer(node);
348 list_del_init(&node->list);
349 list_del_init(&node->lower);
350 if (!RB_EMPTY_NODE(&node->rb_node))
351 rb_erase(&node->rb_node, &tree->rb_root);
352 btrfs_backref_free_node(tree, node);
355 void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
356 struct btrfs_backref_node *node);
358 void btrfs_backref_release_cache(struct btrfs_backref_cache *cache);
360 static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
361 u64 bytenr, int errno)
363 btrfs_panic(fs_info, errno,
364 "Inconsistency in backref cache found at offset %llu",
368 int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
369 struct btrfs_path *path,
370 struct btrfs_backref_iter *iter,
371 struct btrfs_key *node_key,
372 struct btrfs_backref_node *cur);
374 int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
375 struct btrfs_backref_node *start);
377 void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
378 struct btrfs_backref_node *node);