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