fs/btrfs/backref.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003  * Copyright (C) 2011 STRATO.  All rights reserved.
0004  */
0005
0006 #ifndef BTRFS_BACKREF_H
0007 #define BTRFS_BACKREF_H
0008
0009 #include <linux/btrfs.h>
0010 #include "ulist.h"
0011 #include "disk-io.h"
0012 #include "extent_io.h"
0013
0014 struct inode_fs_paths {
0015     struct btrfs_path       *btrfs_path;
0016     struct btrfs_root       *fs_root;
0017     struct btrfs_data_container *fspath;
0018 };
0019
0020 typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root,
0021         void *ctx);
0022
0023 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
0024             struct btrfs_path *path, struct btrfs_key *found_key,
0025             u64 *flags);
0026
0027 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
0028                 struct btrfs_key *key, struct btrfs_extent_item *ei,
0029                 u32 item_size, u64 *out_root, u8 *out_level);
0030
0031 int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
0032                 u64 extent_item_objectid,
0033                 u64 extent_offset, int search_commit_root,
0034                 iterate_extent_inodes_t *iterate, void *ctx,
0035                 bool ignore_offset);
0036
0037 int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
0038                 struct btrfs_path *path, void *ctx,
0039                 bool ignore_offset);
0040
0041 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
0042
0043 int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
0044              struct btrfs_fs_info *fs_info, u64 bytenr,
0045              u64 time_seq, struct ulist **leafs,
0046              const u64 *extent_item_pos, bool ignore_offset);
0047 int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
0048              struct btrfs_fs_info *fs_info, u64 bytenr,
0049              u64 time_seq, struct ulist **roots,
0050              bool skip_commit_root_sem);
0051 char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
0052             u32 name_len, unsigned long name_off,
0053             struct extent_buffer *eb_in, u64 parent,
0054             char *dest, u32 size);
0055
0056 struct btrfs_data_container *init_data_container(u32 total_bytes);
0057 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
0058                     struct btrfs_path *path);
0059 void free_ipath(struct inode_fs_paths *ipath);
0060
0061 int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
0062               u64 start_off, struct btrfs_path *path,
0063               struct btrfs_inode_extref **ret_extref,
0064               u64 *found_off);
0065 int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
0066         struct ulist *roots, struct ulist *tmp_ulist);
0067
0068 int __init btrfs_prelim_ref_init(void);
0069 void __cold btrfs_prelim_ref_exit(void);
0070
0071 struct prelim_ref {
0072     struct rb_node rbnode;
0073     u64 root_id;
0074     struct btrfs_key key_for_search;
0075     int level;
0076     int count;
0077     struct extent_inode_elem *inode_list;
0078     u64 parent;
0079     u64 wanted_disk_byte;
0080 };
0081
0082 /*
0083  * Iterate backrefs of one extent.
0084  *
0085  * Now it only supports iteration of tree block in commit root.
0086  */
0087 struct btrfs_backref_iter {
0088     u64 bytenr;
0089     struct btrfs_path *path;
0090     struct btrfs_fs_info *fs_info;
0091     struct btrfs_key cur_key;
0092     u32 item_ptr;
0093     u32 cur_ptr;
0094     u32 end_ptr;
0095 };
0096
0097 struct btrfs_backref_iter *btrfs_backref_iter_alloc(
0098         struct btrfs_fs_info *fs_info, gfp_t gfp_flag);
0099
0100 static inline void btrfs_backref_iter_free(struct btrfs_backref_iter *iter)
0101 {
0102     if (!iter)
0103         return;
0104     btrfs_free_path(iter->path);
0105     kfree(iter);
0106 }
0107
0108 static inline struct extent_buffer *btrfs_backref_get_eb(
0109         struct btrfs_backref_iter *iter)
0110 {
0111     if (!iter)
0112         return NULL;
0113     return iter->path->nodes[0];
0114 }
0115
0116 /*
0117  * For metadata with EXTENT_ITEM key (non-skinny) case, the first inline data
0118  * is btrfs_tree_block_info, without a btrfs_extent_inline_ref header.
0119  *
0120  * This helper determines if that's the case.
0121  */
0122 static inline bool btrfs_backref_has_tree_block_info(
0123         struct btrfs_backref_iter *iter)
0124 {
0125     if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY &&
0126         iter->cur_ptr - iter->item_ptr == sizeof(struct btrfs_extent_item))
0127         return true;
0128     return false;
0129 }
0130
0131 int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr);
0132
0133 int btrfs_backref_iter_next(struct btrfs_backref_iter *iter);
0134
0135 static inline bool btrfs_backref_iter_is_inline_ref(
0136         struct btrfs_backref_iter *iter)
0137 {
0138     if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY ||
0139         iter->cur_key.type == BTRFS_METADATA_ITEM_KEY)
0140         return true;
0141     return false;
0142 }
0143
0144 static inline void btrfs_backref_iter_release(struct btrfs_backref_iter *iter)
0145 {
0146     iter->bytenr = 0;
0147     iter->item_ptr = 0;
0148     iter->cur_ptr = 0;
0149     iter->end_ptr = 0;
0150     btrfs_release_path(iter->path);
0151     memset(&iter->cur_key, 0, sizeof(iter->cur_key));
0152 }
0153
0154 /*
0155  * Backref cache related structures
0156  *
0157  * The whole objective of backref_cache is to build a bi-directional map
0158  * of tree blocks (represented by backref_node) and all their parents.
0159  */
0160
0161 /*
0162  * Represent a tree block in the backref cache
0163  */
0164 struct btrfs_backref_node {
0165     struct {
0166         struct rb_node rb_node;
0167         u64 bytenr;
0168     }; /* Use rb_simple_node for search/insert */
0169
0170     u64 new_bytenr;
0171     /* Objectid of tree block owner, can be not uptodate */
0172     u64 owner;
0173     /* Link to pending, changed or detached list */
0174     struct list_head list;
0175
0176     /* List of upper level edges, which link this node to its parents */
0177     struct list_head upper;
0178     /* List of lower level edges, which link this node to its children */
0179     struct list_head lower;
0180
0181     /* NULL if this node is not tree root */
0182     struct btrfs_root *root;
0183     /* Extent buffer got by COWing the block */
0184     struct extent_buffer *eb;
0185     /* Level of the tree block */
0186     unsigned int level:8;
0187     /* Is the block in a non-shareable tree */
0188     unsigned int cowonly:1;
0189     /* 1 if no child node is in the cache */
0190     unsigned int lowest:1;
0191     /* Is the extent buffer locked */
0192     unsigned int locked:1;
0193     /* Has the block been processed */
0194     unsigned int processed:1;
0195     /* Have backrefs of this block been checked */
0196     unsigned int checked:1;
0197     /*
0198      * 1 if corresponding block has been COWed but some upper level block
0199      * pointers may not point to the new location
0200      */
0201     unsigned int pending:1;
0202     /* 1 if the backref node isn't connected to any other backref node */
0203     unsigned int detached:1;
0204
0205     /*
0206      * For generic purpose backref cache, where we only care if it's a reloc
0207      * root, doesn't care the source subvolid.
0208      */
0209     unsigned int is_reloc_root:1;
0210 };
0211
0212 #define LOWER   0
0213 #define UPPER   1
0214
0215 /*
0216  * Represent an edge connecting upper and lower backref nodes.
0217  */
0218 struct btrfs_backref_edge {
0219     /*
0220      * list[LOWER] is linked to btrfs_backref_node::upper of lower level
0221      * node, and list[UPPER] is linked to btrfs_backref_node::lower of
0222      * upper level node.
0223      *
0224      * Also, build_backref_tree() uses list[UPPER] for pending edges, before
0225      * linking list[UPPER] to its upper level nodes.
0226      */
0227     struct list_head list[2];
0228
0229     /* Two related nodes */
0230     struct btrfs_backref_node *node[2];
0231 };
0232
0233 struct btrfs_backref_cache {
0234     /* Red black tree of all backref nodes in the cache */
0235     struct rb_root rb_root;
0236     /* For passing backref nodes to btrfs_reloc_cow_block */
0237     struct btrfs_backref_node *path[BTRFS_MAX_LEVEL];
0238     /*
0239      * List of blocks that have been COWed but some block pointers in upper
0240      * level blocks may not reflect the new location
0241      */
0242     struct list_head pending[BTRFS_MAX_LEVEL];
0243     /* List of backref nodes with no child node */
0244     struct list_head leaves;
0245     /* List of blocks that have been COWed in current transaction */
0246     struct list_head changed;
0247     /* List of detached backref node. */
0248     struct list_head detached;
0249
0250     u64 last_trans;
0251
0252     int nr_nodes;
0253     int nr_edges;
0254
0255     /* List of unchecked backref edges during backref cache build */
0256     struct list_head pending_edge;
0257
0258     /* List of useless backref nodes during backref cache build */
0259     struct list_head useless_node;
0260
0261     struct btrfs_fs_info *fs_info;
0262
0263     /*
0264      * Whether this cache is for relocation
0265      *
0266      * Reloction backref cache require more info for reloc root compared
0267      * to generic backref cache.
0268      */
0269     unsigned int is_reloc;
0270 };
0271
0272 void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
0273                   struct btrfs_backref_cache *cache, int is_reloc);
0274 struct btrfs_backref_node *btrfs_backref_alloc_node(
0275         struct btrfs_backref_cache *cache, u64 bytenr, int level);
0276 struct btrfs_backref_edge *btrfs_backref_alloc_edge(
0277         struct btrfs_backref_cache *cache);
0278
0279 #define     LINK_LOWER  (1 << 0)
0280 #define     LINK_UPPER  (1 << 1)
0281 static inline void btrfs_backref_link_edge(struct btrfs_backref_edge *edge,
0282                        struct btrfs_backref_node *lower,
0283                        struct btrfs_backref_node *upper,
0284                        int link_which)
0285 {
0286     ASSERT(upper && lower && upper->level == lower->level + 1);
0287     edge->node[LOWER] = lower;
0288     edge->node[UPPER] = upper;
0289     if (link_which & LINK_LOWER)
0290         list_add_tail(&edge->list[LOWER], &lower->upper);
0291     if (link_which & LINK_UPPER)
0292         list_add_tail(&edge->list[UPPER], &upper->lower);
0293 }
0294
0295 static inline void btrfs_backref_free_node(struct btrfs_backref_cache *cache,
0296                        struct btrfs_backref_node *node)
0297 {
0298     if (node) {
0299         ASSERT(list_empty(&node->list));
0300         ASSERT(list_empty(&node->lower));
0301         ASSERT(node->eb == NULL);
0302         cache->nr_nodes--;
0303         btrfs_put_root(node->root);
0304         kfree(node);
0305     }
0306 }
0307
0308 static inline void btrfs_backref_free_edge(struct btrfs_backref_cache *cache,
0309                        struct btrfs_backref_edge *edge)
0310 {
0311     if (edge) {
0312         cache->nr_edges--;
0313         kfree(edge);
0314     }
0315 }
0316
0317 static inline void btrfs_backref_unlock_node_buffer(
0318         struct btrfs_backref_node *node)
0319 {
0320     if (node->locked) {
0321         btrfs_tree_unlock(node->eb);
0322         node->locked = 0;
0323     }
0324 }
0325
0326 static inline void btrfs_backref_drop_node_buffer(
0327         struct btrfs_backref_node *node)
0328 {
0329     if (node->eb) {
0330         btrfs_backref_unlock_node_buffer(node);
0331         free_extent_buffer(node->eb);
0332         node->eb = NULL;
0333     }
0334 }
0335
0336 /*
0337  * Drop the backref node from cache without cleaning up its children
0338  * edges.
0339  *
0340  * This can only be called on node without parent edges.
0341  * The children edges are still kept as is.
0342  */
0343 static inline void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
0344                        struct btrfs_backref_node *node)
0345 {
0346     ASSERT(list_empty(&node->upper));
0347
0348     btrfs_backref_drop_node_buffer(node);
0349     list_del_init(&node->list);
0350     list_del_init(&node->lower);
0351     if (!RB_EMPTY_NODE(&node->rb_node))
0352         rb_erase(&node->rb_node, &tree->rb_root);
0353     btrfs_backref_free_node(tree, node);
0354 }
0355
0356 void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
0357                 struct btrfs_backref_node *node);
0358
0359 void btrfs_backref_release_cache(struct btrfs_backref_cache *cache);
0360
0361 static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
0362                        u64 bytenr, int errno)
0363 {
0364     btrfs_panic(fs_info, errno,
0365             "Inconsistency in backref cache found at offset %llu",
0366             bytenr);
0367 }
0368
0369 int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
0370                 struct btrfs_path *path,
0371                 struct btrfs_backref_iter *iter,
0372                 struct btrfs_key *node_key,
0373                 struct btrfs_backref_node *cur);
0374
0375 int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
0376                      struct btrfs_backref_node *start);
0377
0378 void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
0379                  struct btrfs_backref_node *node);
0380
0381 #endif