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,
  51                          bool skip_commit_root_sem);
  52 char *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
  57 struct btrfs_data_container *init_data_container(u32 total_bytes);
  58 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
  59                                         struct btrfs_path *path);
  60 void free_ipath(struct inode_fs_paths *ipath);
  61
  62 int 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);
  66 int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
  67                 struct ulist *roots, struct ulist *tmp_ulist);
  68
  69 int __init btrfs_prelim_ref_init(void);
  70 void __cold btrfs_prelim_ref_exit(void);
  71
  72 struct 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  */
  88 struct 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
  98 struct btrfs_backref_iter *btrfs_backref_iter_alloc(
  99                 struct btrfs_fs_info *fs_info, gfp_t gfp_flag);
 100
 101 static 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
 109 static 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  */
 123 static 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
 132 int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr);
 133
 134 int btrfs_backref_iter_next(struct btrfs_backref_iter *iter);
 135
 136 static 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
 145 static 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  */
 165 struct 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  */
 219 struct 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
 234 struct 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
 273 void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
 274                               struct btrfs_backref_cache *cache, int is_reloc);
 275 struct btrfs_backref_node *btrfs_backref_alloc_node(
 276                 struct btrfs_backref_cache *cache, u64 bytenr, int level);
 277 struct 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)
 282 static 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
 296 static 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
 309 static 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
 318 static 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
 327 static 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  */
 344 static 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
 357 void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
 358                                 struct btrfs_backref_node *node);
 359
 360 void btrfs_backref_release_cache(struct btrfs_backref_cache *cache);
 361
 362 static 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
 370 int 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
 376 int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
 377                                      struct btrfs_backref_node *start);
 378
 379 void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
 380                                  struct btrfs_backref_node *node);
 381
 382 #endif