fs/btrfs/backref.h

   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
 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
 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  */
 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
 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
 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)
 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
 295 static inline void btrfs_backref_free_node(struct btrfs_backref_cache *cache,
 296                                            struct btrfs_backref_node *node)
 297 {
 298         if (node) {
 299                 cache->nr_nodes--;
 300                 btrfs_put_root(node->root);
 301                 kfree(node);
 302         }
 303 }
 304
 305 static inline void btrfs_backref_free_edge(struct btrfs_backref_cache *cache,
 306                                            struct btrfs_backref_edge *edge)
 307 {
 308         if (edge) {
 309                 cache->nr_edges--;
 310                 kfree(edge);
 311         }
 312 }
 313
 314 static inline void btrfs_backref_unlock_node_buffer(
 315                 struct btrfs_backref_node *node)
 316 {
 317         if (node->locked) {
 318                 btrfs_tree_unlock(node->eb);
 319                 node->locked = 0;
 320         }
 321 }
 322
 323 static inline void btrfs_backref_drop_node_buffer(
 324                 struct btrfs_backref_node *node)
 325 {
 326         if (node->eb) {
 327                 btrfs_backref_unlock_node_buffer(node);
 328                 free_extent_buffer(node->eb);
 329                 node->eb = NULL;
 330         }
 331 }
 332
 333 /*
 334  * Drop the backref node from cache without cleaning up its children
 335  * edges.
 336  *
 337  * This can only be called on node without parent edges.
 338  * The children edges are still kept as is.
 339  */
 340 static inline void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
 341                                            struct btrfs_backref_node *node)
 342 {
 343         BUG_ON(!list_empty(&node->upper));
 344
 345         btrfs_backref_drop_node_buffer(node);
 346         list_del(&node->list);
 347         list_del(&node->lower);
 348         if (!RB_EMPTY_NODE(&node->rb_node))
 349                 rb_erase(&node->rb_node, &tree->rb_root);
 350         btrfs_backref_free_node(tree, node);
 351 }
 352
 353 void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
 354                                 struct btrfs_backref_node *node);
 355
 356 void btrfs_backref_release_cache(struct btrfs_backref_cache *cache);
 357
 358 static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
 359                                        u64 bytenr, int errno)
 360 {
 361         btrfs_panic(fs_info, errno,
 362                     "Inconsistency in backref cache found at offset %llu",
 363                     bytenr);
 364 }
 365
 366 int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
 367                                 struct btrfs_path *path,
 368                                 struct btrfs_backref_iter *iter,
 369                                 struct btrfs_key *node_key,
 370                                 struct btrfs_backref_node *cur);
 371
 372 int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
 373                                      struct btrfs_backref_node *start);
 374
 375 void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
 376                                  struct btrfs_backref_node *node);
 377
 378 #endif