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); 116 117 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 } 124 125 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 */ 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); 151 152 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 } 160 161 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) 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 } 311 312 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 } 324 325 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 } 333 334 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 } 342 343 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 */ 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); 377 378 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