1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2011 STRATO. All rights reserved.
4 */
5
6 #ifndef BTRFS_BACKREF_H
7 #define BTRFS_BACKREF_H
8
9 #include <linux/btrfs.h>
10 #include "ulist.h"
11 #include "disk-io.h"
12 #include "extent_io.h"
13
14 struct inode_fs_paths {
15 struct btrfs_path *btrfs_path;
16 struct btrfs_root *fs_root;
17 struct btrfs_data_container *fspath;
18 };
19
20 struct btrfs_backref_shared_cache_entry {
21 u64 bytenr;
22 u64 gen;
23 bool is_shared;
24 };
25
26 struct btrfs_backref_shared_cache {
27 /*
28 * A path from a root to a leaf that has a file extent item pointing to
29 * a given data extent should never exceed the maximum b+tree height.
30 */
31 struct btrfs_backref_shared_cache_entry entries[BTRFS_MAX_LEVEL];
32 bool use_cache;
33 };
34
35 typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root,
36 void *ctx);
37
38 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
39 struct btrfs_path *path, struct btrfs_key *found_key,
40 u64 *flags);
41
42 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
43 struct btrfs_key *key, struct btrfs_extent_item *ei,
44 u32 item_size, u64 *out_root, u8 *out_level);
45
46 int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
47 u64 extent_item_objectid,
48 u64 extent_offset, int search_commit_root,
49 iterate_extent_inodes_t *iterate, void *ctx,
50 bool ignore_offset);
51
52 int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
53 struct btrfs_path *path, void *ctx,
54 bool ignore_offset);
55
56 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
57
58 int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
59 struct btrfs_fs_info *fs_info, u64 bytenr,
60 u64 time_seq, struct ulist **leafs,
61 const u64 *extent_item_pos, bool ignore_offset);
62 int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
63 struct btrfs_fs_info *fs_info, u64 bytenr,
64 u64 time_seq, struct ulist **roots,
65 bool skip_commit_root_sem);
66 char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
67 u32 name_len, unsigned long name_off,
68 struct extent_buffer *eb_in, u64 parent,
69 char *dest, u32 size);
70
71 struct btrfs_data_container *init_data_container(u32 total_bytes);
72 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
73 struct btrfs_path *path);
74 void free_ipath(struct inode_fs_paths *ipath);
75
76 int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
77 u64 start_off, struct btrfs_path *path,
78 struct btrfs_inode_extref **ret_extref,
79 u64 *found_off);
80 int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
81 u64 extent_gen,
82 struct ulist *roots, struct ulist *tmp,
83 struct btrfs_backref_shared_cache *cache);
84
85 int __init btrfs_prelim_ref_init(void);
86 void __cold btrfs_prelim_ref_exit(void);
87
88 struct prelim_ref {
89 struct rb_node rbnode;
90 u64 root_id;
91 struct btrfs_key key_for_search;
92 int level;
93 int count;
94 struct extent_inode_elem *inode_list;
95 u64 parent;
96 u64 wanted_disk_byte;
97 };
98
99 /*
100 * Iterate backrefs of one extent.
101 *
102 * Now it only supports iteration of tree block in commit root.
103 */
104 struct btrfs_backref_iter {
105 u64 bytenr;
106 struct btrfs_path *path;
107 struct btrfs_fs_info *fs_info;
108 struct btrfs_key cur_key;
109 u32 item_ptr;
110 u32 cur_ptr;
111 u32 end_ptr;
112 };
113
114 struct btrfs_backref_iter *btrfs_backref_iter_alloc(
115 struct btrfs_fs_info *fs_info, gfp_t gfp_flag);
116
btrfs_backref_iter_free(struct btrfs_backref_iter * iter)117 static inline void btrfs_backref_iter_free(struct btrfs_backref_iter *iter)
118 {
119 if (!iter)
120 return;
121 btrfs_free_path(iter->path);
122 kfree(iter);
123 }
124
btrfs_backref_get_eb(struct btrfs_backref_iter * iter)125 static inline struct extent_buffer *btrfs_backref_get_eb(
126 struct btrfs_backref_iter *iter)
127 {
128 if (!iter)
129 return NULL;
130 return iter->path->nodes[0];
131 }
132
133 /*
134 * For metadata with EXTENT_ITEM key (non-skinny) case, the first inline data
135 * is btrfs_tree_block_info, without a btrfs_extent_inline_ref header.
136 *
137 * This helper determines if that's the case.
138 */
btrfs_backref_has_tree_block_info(struct btrfs_backref_iter * iter)139 static inline bool btrfs_backref_has_tree_block_info(
140 struct btrfs_backref_iter *iter)
141 {
142 if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY &&
143 iter->cur_ptr - iter->item_ptr == sizeof(struct btrfs_extent_item))
144 return true;
145 return false;
146 }
147
148 int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr);
149
150 int btrfs_backref_iter_next(struct btrfs_backref_iter *iter);
151
btrfs_backref_iter_is_inline_ref(struct btrfs_backref_iter * iter)152 static inline bool btrfs_backref_iter_is_inline_ref(
153 struct btrfs_backref_iter *iter)
154 {
155 if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY ||
156 iter->cur_key.type == BTRFS_METADATA_ITEM_KEY)
157 return true;
158 return false;
159 }
160
btrfs_backref_iter_release(struct btrfs_backref_iter * iter)161 static inline void btrfs_backref_iter_release(struct btrfs_backref_iter *iter)
162 {
163 iter->bytenr = 0;
164 iter->item_ptr = 0;
165 iter->cur_ptr = 0;
166 iter->end_ptr = 0;
167 btrfs_release_path(iter->path);
168 memset(&iter->cur_key, 0, sizeof(iter->cur_key));
169 }
170
171 /*
172 * Backref cache related structures
173 *
174 * The whole objective of backref_cache is to build a bi-directional map
175 * of tree blocks (represented by backref_node) and all their parents.
176 */
177
178 /*
179 * Represent a tree block in the backref cache
180 */
181 struct btrfs_backref_node {
182 struct {
183 struct rb_node rb_node;
184 u64 bytenr;
185 }; /* Use rb_simple_node for search/insert */
186
187 u64 new_bytenr;
188 /* Objectid of tree block owner, can be not uptodate */
189 u64 owner;
190 /* Link to pending, changed or detached list */
191 struct list_head list;
192
193 /* List of upper level edges, which link this node to its parents */
194 struct list_head upper;
195 /* List of lower level edges, which link this node to its children */
196 struct list_head lower;
197
198 /* NULL if this node is not tree root */
199 struct btrfs_root *root;
200 /* Extent buffer got by COWing the block */
201 struct extent_buffer *eb;
202 /* Level of the tree block */
203 unsigned int level:8;
204 /* Is the block in a non-shareable tree */
205 unsigned int cowonly:1;
206 /* 1 if no child node is in the cache */
207 unsigned int lowest:1;
208 /* Is the extent buffer locked */
209 unsigned int locked:1;
210 /* Has the block been processed */
211 unsigned int processed:1;
212 /* Have backrefs of this block been checked */
213 unsigned int checked:1;
214 /*
215 * 1 if corresponding block has been COWed but some upper level block
216 * pointers may not point to the new location
217 */
218 unsigned int pending:1;
219 /* 1 if the backref node isn't connected to any other backref node */
220 unsigned int detached:1;
221
222 /*
223 * For generic purpose backref cache, where we only care if it's a reloc
224 * root, doesn't care the source subvolid.
225 */
226 unsigned int is_reloc_root:1;
227 };
228
229 #define LOWER 0
230 #define UPPER 1
231
232 /*
233 * Represent an edge connecting upper and lower backref nodes.
234 */
235 struct btrfs_backref_edge {
236 /*
237 * list[LOWER] is linked to btrfs_backref_node::upper of lower level
238 * node, and list[UPPER] is linked to btrfs_backref_node::lower of
239 * upper level node.
240 *
241 * Also, build_backref_tree() uses list[UPPER] for pending edges, before
242 * linking list[UPPER] to its upper level nodes.
243 */
244 struct list_head list[2];
245
246 /* Two related nodes */
247 struct btrfs_backref_node *node[2];
248 };
249
250 struct btrfs_backref_cache {
251 /* Red black tree of all backref nodes in the cache */
252 struct rb_root rb_root;
253 /* For passing backref nodes to btrfs_reloc_cow_block */
254 struct btrfs_backref_node *path[BTRFS_MAX_LEVEL];
255 /*
256 * List of blocks that have been COWed but some block pointers in upper
257 * level blocks may not reflect the new location
258 */
259 struct list_head pending[BTRFS_MAX_LEVEL];
260 /* List of backref nodes with no child node */
261 struct list_head leaves;
262 /* List of blocks that have been COWed in current transaction */
263 struct list_head changed;
264 /* List of detached backref node. */
265 struct list_head detached;
266
267 u64 last_trans;
268
269 int nr_nodes;
270 int nr_edges;
271
272 /* List of unchecked backref edges during backref cache build */
273 struct list_head pending_edge;
274
275 /* List of useless backref nodes during backref cache build */
276 struct list_head useless_node;
277
278 struct btrfs_fs_info *fs_info;
279
280 /*
281 * Whether this cache is for relocation
282 *
283 * Reloction backref cache require more info for reloc root compared
284 * to generic backref cache.
285 */
286 unsigned int is_reloc;
287 };
288
289 void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
290 struct btrfs_backref_cache *cache, int is_reloc);
291 struct btrfs_backref_node *btrfs_backref_alloc_node(
292 struct btrfs_backref_cache *cache, u64 bytenr, int level);
293 struct btrfs_backref_edge *btrfs_backref_alloc_edge(
294 struct btrfs_backref_cache *cache);
295
296 #define LINK_LOWER (1 << 0)
297 #define LINK_UPPER (1 << 1)
btrfs_backref_link_edge(struct btrfs_backref_edge * edge,struct btrfs_backref_node * lower,struct btrfs_backref_node * upper,int link_which)298 static inline void btrfs_backref_link_edge(struct btrfs_backref_edge *edge,
299 struct btrfs_backref_node *lower,
300 struct btrfs_backref_node *upper,
301 int link_which)
302 {
303 ASSERT(upper && lower && upper->level == lower->level + 1);
304 edge->node[LOWER] = lower;
305 edge->node[UPPER] = upper;
306 if (link_which & LINK_LOWER)
307 list_add_tail(&edge->list[LOWER], &lower->upper);
308 if (link_which & LINK_UPPER)
309 list_add_tail(&edge->list[UPPER], &upper->lower);
310 }
311
btrfs_backref_free_node(struct btrfs_backref_cache * cache,struct btrfs_backref_node * node)312 static inline void btrfs_backref_free_node(struct btrfs_backref_cache *cache,
313 struct btrfs_backref_node *node)
314 {
315 if (node) {
316 ASSERT(list_empty(&node->list));
317 ASSERT(list_empty(&node->lower));
318 ASSERT(node->eb == NULL);
319 cache->nr_nodes--;
320 btrfs_put_root(node->root);
321 kfree(node);
322 }
323 }
324
btrfs_backref_free_edge(struct btrfs_backref_cache * cache,struct btrfs_backref_edge * edge)325 static inline void btrfs_backref_free_edge(struct btrfs_backref_cache *cache,
326 struct btrfs_backref_edge *edge)
327 {
328 if (edge) {
329 cache->nr_edges--;
330 kfree(edge);
331 }
332 }
333
btrfs_backref_unlock_node_buffer(struct btrfs_backref_node * node)334 static inline void btrfs_backref_unlock_node_buffer(
335 struct btrfs_backref_node *node)
336 {
337 if (node->locked) {
338 btrfs_tree_unlock(node->eb);
339 node->locked = 0;
340 }
341 }
342
btrfs_backref_drop_node_buffer(struct btrfs_backref_node * node)343 static inline void btrfs_backref_drop_node_buffer(
344 struct btrfs_backref_node *node)
345 {
346 if (node->eb) {
347 btrfs_backref_unlock_node_buffer(node);
348 free_extent_buffer(node->eb);
349 node->eb = NULL;
350 }
351 }
352
353 /*
354 * Drop the backref node from cache without cleaning up its children
355 * edges.
356 *
357 * This can only be called on node without parent edges.
358 * The children edges are still kept as is.
359 */
btrfs_backref_drop_node(struct btrfs_backref_cache * tree,struct btrfs_backref_node * node)360 static inline void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
361 struct btrfs_backref_node *node)
362 {
363 ASSERT(list_empty(&node->upper));
364
365 btrfs_backref_drop_node_buffer(node);
366 list_del_init(&node->list);
367 list_del_init(&node->lower);
368 if (!RB_EMPTY_NODE(&node->rb_node))
369 rb_erase(&node->rb_node, &tree->rb_root);
370 btrfs_backref_free_node(tree, node);
371 }
372
373 void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
374 struct btrfs_backref_node *node);
375
376 void btrfs_backref_release_cache(struct btrfs_backref_cache *cache);
377
btrfs_backref_panic(struct btrfs_fs_info * fs_info,u64 bytenr,int errno)378 static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
379 u64 bytenr, int errno)
380 {
381 btrfs_panic(fs_info, errno,
382 "Inconsistency in backref cache found at offset %llu",
383 bytenr);
384 }
385
386 int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
387 struct btrfs_path *path,
388 struct btrfs_backref_iter *iter,
389 struct btrfs_key *node_key,
390 struct btrfs_backref_node *cur);
391
392 int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
393 struct btrfs_backref_node *start);
394
395 void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
396 struct btrfs_backref_node *node);
397
398 #endif
399