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