diff options
Diffstat (limited to 'fs/btrfs/backref.c')
| -rw-r--r-- | fs/btrfs/backref.c | 1660 |
1 files changed, 1103 insertions, 557 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index c9ee579bc5a6..78da47a3d00e 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -15,49 +15,77 @@ #include "locking.h" #include "misc.h" #include "tree-mod-log.h" +#include "fs.h" +#include "accessors.h" +#include "extent-tree.h" +#include "relocation.h" +#include "tree-checker.h" -/* Just an arbitrary number so we can be sure this happened */ -#define BACKREF_FOUND_SHARED 6 +/* Just arbitrary numbers so we can be sure one of these happened. */ +#define BACKREF_FOUND_SHARED 6 +#define BACKREF_FOUND_NOT_SHARED 7 struct extent_inode_elem { u64 inum; u64 offset; + u64 num_bytes; struct extent_inode_elem *next; }; -static int check_extent_in_eb(const struct btrfs_key *key, +static int check_extent_in_eb(struct btrfs_backref_walk_ctx *ctx, + const struct btrfs_key *key, const struct extent_buffer *eb, const struct btrfs_file_extent_item *fi, - u64 extent_item_pos, - struct extent_inode_elem **eie, - bool ignore_offset) + struct extent_inode_elem **eie) { - u64 offset = 0; + const u64 data_len = btrfs_file_extent_num_bytes(eb, fi); + u64 offset = key->offset; struct extent_inode_elem *e; + const u64 *root_ids; + int root_count; + bool cached; - if (!ignore_offset && + if (!ctx->ignore_extent_item_pos && !btrfs_file_extent_compression(eb, fi) && !btrfs_file_extent_encryption(eb, fi) && !btrfs_file_extent_other_encoding(eb, fi)) { u64 data_offset; - u64 data_len; data_offset = btrfs_file_extent_offset(eb, fi); - data_len = btrfs_file_extent_num_bytes(eb, fi); - if (extent_item_pos < data_offset || - extent_item_pos >= data_offset + data_len) + if (ctx->extent_item_pos < data_offset || + ctx->extent_item_pos >= data_offset + data_len) return 1; - offset = extent_item_pos - data_offset; + offset += ctx->extent_item_pos - data_offset; } + if (!ctx->indirect_ref_iterator || !ctx->cache_lookup) + goto add_inode_elem; + + cached = ctx->cache_lookup(eb->start, ctx->user_ctx, &root_ids, + &root_count); + if (!cached) + goto add_inode_elem; + + for (int i = 0; i < root_count; i++) { + int ret; + + ret = ctx->indirect_ref_iterator(key->objectid, offset, + data_len, root_ids[i], + ctx->user_ctx); + if (ret) + return ret; + } + +add_inode_elem: e = kmalloc(sizeof(*e), GFP_NOFS); if (!e) return -ENOMEM; e->next = *eie; e->inum = key->objectid; - e->offset = key->offset + offset; + e->offset = offset; + e->num_bytes = data_len; *eie = e; return 0; @@ -73,10 +101,9 @@ static void free_inode_elem_list(struct extent_inode_elem *eie) } } -static int find_extent_in_eb(const struct extent_buffer *eb, - u64 wanted_disk_byte, u64 extent_item_pos, - struct extent_inode_elem **eie, - bool ignore_offset) +static int find_extent_in_eb(struct btrfs_backref_walk_ctx *ctx, + const struct extent_buffer *eb, + struct extent_inode_elem **eie) { u64 disk_byte; struct btrfs_key key; @@ -102,11 +129,11 @@ static int find_extent_in_eb(const struct extent_buffer *eb, continue; /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */ disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); - if (disk_byte != wanted_disk_byte) + if (disk_byte != ctx->bytenr) continue; - ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie, ignore_offset); - if (ret < 0) + ret = check_extent_in_eb(ctx, &key, eb, fi, eie); + if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || ret < 0) return ret; } @@ -135,9 +162,30 @@ struct preftrees { * - decremented when a ref->count transitions to <1 */ struct share_check { - u64 root_objectid; + struct btrfs_backref_share_check_ctx *ctx; + struct btrfs_root *root; u64 inum; + u64 data_bytenr; + u64 data_extent_gen; + /* + * Counts number of inodes that refer to an extent (different inodes in + * the same root or different roots) that we could find. The sharedness + * check typically stops once this counter gets greater than 1, so it + * may not reflect the total number of inodes. + */ int share_count; + /* + * The number of times we found our inode refers to the data extent we + * are determining the sharedness. In other words, how many file extent + * items we could find for our inode that point to our target data + * extent. The value we get here after finishing the extent sharedness + * check may be smaller than reality, but if it ends up being greater + * than 1, then we know for sure the inode has multiple file extent + * items that point to our inode, and we can safely assume it's useful + * to cache the sharedness check result. + */ + int self_ref_count; + bool have_delayed_delete_refs; }; static inline int extent_is_shared(struct share_check *sc) @@ -150,10 +198,7 @@ static struct kmem_cache *btrfs_prelim_ref_cache; int __init btrfs_prelim_ref_init(void) { btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref", - sizeof(struct prelim_ref), - 0, - SLAB_MEM_SPREAD, - NULL); + sizeof(struct prelim_ref), 0, 0, NULL); if (!btrfs_prelim_ref_cache) return -ENOMEM; return 0; @@ -174,8 +219,8 @@ static void free_pref(struct prelim_ref *ref) * A -1 return indicates ref1 is a 'lower' block than ref2, while 1 * indicates a 'higher' block. */ -static int prelim_ref_compare(struct prelim_ref *ref1, - struct prelim_ref *ref2) +static int prelim_ref_compare(const struct prelim_ref *ref1, + const struct prelim_ref *ref2) { if (ref1->level < ref2->level) return -1; @@ -205,8 +250,23 @@ static int prelim_ref_compare(struct prelim_ref *ref1, return 0; } +static int prelim_ref_rb_add_cmp(const struct rb_node *new, + const struct rb_node *exist) +{ + const struct prelim_ref *ref_new = + rb_entry(new, struct prelim_ref, rbnode); + const struct prelim_ref *ref_exist = + rb_entry(exist, struct prelim_ref, rbnode); + + /* + * prelim_ref_compare() expects the first parameter as the existing one, + * different from the rb_find_add_cached() order. + */ + return prelim_ref_compare(ref_exist, ref_new); +} + static void update_share_count(struct share_check *sc, int oldcount, - int newcount) + int newcount, const struct prelim_ref *newref) { if ((!sc) || (oldcount == 0 && newcount < 1)) return; @@ -215,6 +275,11 @@ static void update_share_count(struct share_check *sc, int oldcount, sc->share_count--; else if (oldcount < 1 && newcount > 0) sc->share_count++; + + if (newref->root_id == btrfs_root_id(sc->root) && + newref->wanted_disk_byte == sc->data_bytenr && + newref->key_for_search.objectid == sc->inum) + sc->self_ref_count += newref->count; } /* @@ -228,55 +293,39 @@ static void prelim_ref_insert(const struct btrfs_fs_info *fs_info, struct share_check *sc) { struct rb_root_cached *root; - struct rb_node **p; - struct rb_node *parent = NULL; - struct prelim_ref *ref; - int result; - bool leftmost = true; + struct rb_node *exist; root = &preftree->root; - p = &root->rb_root.rb_node; + exist = rb_find_add_cached(&newref->rbnode, root, prelim_ref_rb_add_cmp); + if (exist) { + struct prelim_ref *ref = rb_entry(exist, struct prelim_ref, rbnode); + /* Identical refs, merge them and free @newref */ + struct extent_inode_elem *eie = ref->inode_list; - while (*p) { - parent = *p; - ref = rb_entry(parent, struct prelim_ref, rbnode); - result = prelim_ref_compare(ref, newref); - if (result < 0) { - p = &(*p)->rb_left; - } else if (result > 0) { - p = &(*p)->rb_right; - leftmost = false; - } else { - /* Identical refs, merge them and free @newref */ - struct extent_inode_elem *eie = ref->inode_list; + while (eie && eie->next) + eie = eie->next; - while (eie && eie->next) - eie = eie->next; - - if (!eie) - ref->inode_list = newref->inode_list; - else - eie->next = newref->inode_list; - trace_btrfs_prelim_ref_merge(fs_info, ref, newref, - preftree->count); - /* - * A delayed ref can have newref->count < 0. - * The ref->count is updated to follow any - * BTRFS_[ADD|DROP]_DELAYED_REF actions. - */ - update_share_count(sc, ref->count, - ref->count + newref->count); - ref->count += newref->count; - free_pref(newref); - return; - } + if (!eie) + ref->inode_list = newref->inode_list; + else + eie->next = newref->inode_list; + trace_btrfs_prelim_ref_merge(fs_info, ref, newref, + preftree->count); + /* + * A delayed ref can have newref->count < 0. + * The ref->count is updated to follow any + * BTRFS_[ADD|DROP]_DELAYED_REF actions. + */ + update_share_count(sc, ref->count, + ref->count + newref->count, newref); + ref->count += newref->count; + free_pref(newref); + return; } - update_share_count(sc, 0, newref->count); + update_share_count(sc, 0, newref->count, newref); preftree->count++; trace_btrfs_prelim_ref_insert(fs_info, newref, NULL, preftree->count); - rb_link_node(&newref->rbnode, parent, p); - rb_insert_color_cached(&newref->rbnode, root, leftmost); } /* @@ -288,8 +337,10 @@ static void prelim_release(struct preftree *preftree) struct prelim_ref *ref, *next_ref; rbtree_postorder_for_each_entry_safe(ref, next_ref, - &preftree->root.rb_root, rbnode) + &preftree->root.rb_root, rbnode) { + free_inode_elem_list(ref->inode_list); free_pref(ref); + } preftree->root = RB_ROOT_CACHED; preftree->count = 0; @@ -413,11 +464,11 @@ static int is_shared_data_backref(struct preftrees *preftrees, u64 bytenr) return 0; } -static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, +static int add_all_parents(struct btrfs_backref_walk_ctx *ctx, + struct btrfs_root *root, struct btrfs_path *path, struct ulist *parents, struct preftrees *preftrees, struct prelim_ref *ref, - int level, u64 time_seq, const u64 *extent_item_pos, - bool ignore_offset) + int level) { int ret = 0; int slot; @@ -430,6 +481,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, u64 wanted_disk_byte = ref->wanted_disk_byte; u64 count = 0; u64 data_offset; + u8 type; if (level != 0) { eb = path->nodes[level]; @@ -453,10 +505,10 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, if (path->slots[0] >= btrfs_header_nritems(eb) || is_shared_data_backref(preftrees, eb->start) || ref->root_id != btrfs_header_owner(eb)) { - if (time_seq == BTRFS_SEQ_LAST) + if (ctx->time_seq == BTRFS_SEQ_LAST) ret = btrfs_next_leaf(root, path); else - ret = btrfs_next_old_leaf(root, path, time_seq); + ret = btrfs_next_old_leaf(root, path, ctx->time_seq); } while (!ret && count < ref->count) { @@ -477,13 +529,16 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, if (slot == 0 && (is_shared_data_backref(preftrees, eb->start) || ref->root_id != btrfs_header_owner(eb))) { - if (time_seq == BTRFS_SEQ_LAST) + if (ctx->time_seq == BTRFS_SEQ_LAST) ret = btrfs_next_leaf(root, path); else - ret = btrfs_next_old_leaf(root, path, time_seq); + ret = btrfs_next_old_leaf(root, path, ctx->time_seq); continue; } fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); + type = btrfs_file_extent_type(eb, fi); + if (type == BTRFS_FILE_EXTENT_INLINE) + goto next; disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); data_offset = btrfs_file_extent_offset(eb, fi); @@ -494,11 +549,10 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, count++; else goto next; - if (extent_item_pos) { - ret = check_extent_in_eb(&key, eb, fi, - *extent_item_pos, - &eie, ignore_offset); - if (ret < 0) + if (!ctx->skip_inode_ref_list) { + ret = check_extent_in_eb(ctx, &key, eb, fi, &eie); + if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || + ret < 0) break; } if (ret > 0) @@ -507,7 +561,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, eie, (void **)&old, GFP_NOFS); if (ret < 0) break; - if (!ret && extent_item_pos) { + if (!ret && !ctx->skip_inode_ref_list) { while (old->next) old = old->next; old->next = eie; @@ -515,16 +569,17 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, eie = NULL; } next: - if (time_seq == BTRFS_SEQ_LAST) + if (ctx->time_seq == BTRFS_SEQ_LAST) ret = btrfs_next_item(root, path); else - ret = btrfs_next_old_item(root, path, time_seq); + ret = btrfs_next_old_item(root, path, ctx->time_seq); } - if (ret > 0) - ret = 0; - else if (ret < 0) + if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || ret < 0) free_inode_elem_list(eie); + else if (ret > 0) + ret = 0; + return ret; } @@ -532,11 +587,10 @@ next: * resolve an indirect backref in the form (root_id, key, level) * to a logical address */ -static int resolve_indirect_ref(struct btrfs_fs_info *fs_info, - struct btrfs_path *path, u64 time_seq, +static int resolve_indirect_ref(struct btrfs_backref_walk_ctx *ctx, + struct btrfs_path *path, struct preftrees *preftrees, - struct prelim_ref *ref, struct ulist *parents, - const u64 *extent_item_pos, bool ignore_offset) + struct prelim_ref *ref, struct ulist *parents) { struct btrfs_root *root; struct extent_buffer *eb; @@ -554,9 +608,9 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info, * here. */ if (path->search_commit_root) - root = btrfs_get_fs_root_commit_root(fs_info, path, ref->root_id); + root = btrfs_get_fs_root_commit_root(ctx->fs_info, path, ref->root_id); else - root = btrfs_get_fs_root(fs_info, ref->root_id, false); + root = btrfs_get_fs_root(ctx->fs_info, ref->root_id, false); if (IS_ERR(root)) { ret = PTR_ERR(root); goto out_free; @@ -568,17 +622,17 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info, goto out; } - if (btrfs_is_testing(fs_info)) { + if (btrfs_is_testing(ctx->fs_info)) { ret = -ENOENT; goto out; } if (path->search_commit_root) root_level = btrfs_header_level(root->commit_root); - else if (time_seq == BTRFS_SEQ_LAST) + else if (ctx->time_seq == BTRFS_SEQ_LAST) root_level = btrfs_header_level(root->node); else - root_level = btrfs_old_root_level(root, time_seq); + root_level = btrfs_old_root_level(root, ctx->time_seq); if (root_level + 1 == level) goto out; @@ -606,16 +660,15 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info, search_key.offset >= LLONG_MAX) search_key.offset = 0; path->lowest_level = level; - if (time_seq == BTRFS_SEQ_LAST) + if (ctx->time_seq == BTRFS_SEQ_LAST) ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); else - ret = btrfs_search_old_slot(root, &search_key, path, time_seq); + ret = btrfs_search_old_slot(root, &search_key, path, ctx->time_seq); - btrfs_debug(fs_info, - "search slot in root %llu (level %d, ref count %d) returned %d for key (%llu %u %llu)", - ref->root_id, level, ref->count, ret, - ref->key_for_search.objectid, ref->key_for_search.type, - ref->key_for_search.offset); + btrfs_debug(ctx->fs_info, +"search slot in root %llu (level %d, ref count %d) returned %d for key " BTRFS_KEY_FMT, + ref->root_id, level, ref->count, ret, + BTRFS_KEY_FMT_VALUE(&ref->key_for_search)); if (ret < 0) goto out; @@ -629,8 +682,7 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info, eb = path->nodes[level]; } - ret = add_all_parents(root, path, parents, preftrees, ref, level, - time_seq, extent_item_pos, ignore_offset); + ret = add_all_parents(ctx, root, path, parents, preftrees, ref, level); out: btrfs_put_root(root); out_free: @@ -647,6 +699,18 @@ unode_aux_to_inode_list(struct ulist_node *node) return (struct extent_inode_elem *)(uintptr_t)node->aux; } +static void free_leaf_list(struct ulist *ulist) +{ + struct ulist_node *node; + struct ulist_iterator uiter; + + ULIST_ITER_INIT(&uiter); + while ((node = ulist_next(ulist, &uiter))) + free_inode_elem_list(unode_aux_to_inode_list(node)); + + ulist_free(ulist); +} + /* * We maintain three separate rbtrees: one for direct refs, one for * indirect refs which have a key, and one for indirect refs which do not @@ -663,13 +727,11 @@ unode_aux_to_inode_list(struct ulist_node *node) * rbtree as they are encountered. The new backrefs are subsequently * resolved as above. */ -static int resolve_indirect_refs(struct btrfs_fs_info *fs_info, - struct btrfs_path *path, u64 time_seq, +static int resolve_indirect_refs(struct btrfs_backref_walk_ctx *ctx, + struct btrfs_path *path, struct preftrees *preftrees, - const u64 *extent_item_pos, - struct share_check *sc, bool ignore_offset) + struct share_check *sc) { - int err; int ret = 0; struct ulist *parents; struct ulist_node *node; @@ -688,6 +750,7 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info, */ while ((rnode = rb_first_cached(&preftrees->indirect.root))) { struct prelim_ref *ref; + int ret2; ref = rb_entry(rnode, struct prelim_ref, rbnode); if (WARN(ref->parent, @@ -704,26 +767,23 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info, continue; } - if (sc && sc->root_objectid && - ref->root_id != sc->root_objectid) { + if (sc && ref->root_id != btrfs_root_id(sc->root)) { free_pref(ref); ret = BACKREF_FOUND_SHARED; goto out; } - err = resolve_indirect_ref(fs_info, path, time_seq, preftrees, - ref, parents, extent_item_pos, - ignore_offset); + ret2 = resolve_indirect_ref(ctx, path, preftrees, ref, parents); /* * we can only tolerate ENOENT,otherwise,we should catch error * and return directly. */ - if (err == -ENOENT) { - prelim_ref_insert(fs_info, &preftrees->direct, ref, + if (ret2 == -ENOENT) { + prelim_ref_insert(ctx->fs_info, &preftrees->direct, ref, NULL); continue; - } else if (err) { + } else if (ret2) { free_pref(ref); - ret = err; + ret = ret2; goto out; } @@ -747,7 +807,7 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info, memcpy(new_ref, ref, sizeof(*ref)); new_ref->parent = node->val; new_ref->inode_list = unode_aux_to_inode_list(node); - prelim_ref_insert(fs_info, &preftrees->direct, + prelim_ref_insert(ctx->fs_info, &preftrees->direct, new_ref, NULL); } @@ -755,13 +815,17 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info, * Now it's a direct ref, put it in the direct tree. We must * do this last because the ref could be merged/freed here. */ - prelim_ref_insert(fs_info, &preftrees->direct, ref, NULL); + prelim_ref_insert(ctx->fs_info, &preftrees->direct, ref, NULL); ulist_reinit(parents); cond_resched(); } out: - ulist_free(parents); + /* + * We may have inode lists attached to refs in the parents ulist, so we + * must free them before freeing the ulist and its refs. + */ + free_leaf_list(parents); return ret; } @@ -777,6 +841,8 @@ static int add_missing_keys(struct btrfs_fs_info *fs_info, struct rb_node *node; while ((node = rb_first_cached(&tree->root))) { + struct btrfs_tree_parent_check check = { 0 }; + ref = rb_entry(node, struct prelim_ref, rbnode); rb_erase_cached(node, &tree->root); @@ -784,16 +850,20 @@ static int add_missing_keys(struct btrfs_fs_info *fs_info, BUG_ON(ref->key_for_search.type); BUG_ON(!ref->wanted_disk_byte); - eb = read_tree_block(fs_info, ref->wanted_disk_byte, - ref->root_id, 0, ref->level - 1, NULL); + check.level = ref->level - 1; + check.owner_root = ref->root_id; + + eb = read_tree_block(fs_info, ref->wanted_disk_byte, &check); if (IS_ERR(eb)) { free_pref(ref); return PTR_ERR(eb); - } else if (!extent_buffer_uptodate(eb)) { + } + if (unlikely(!extent_buffer_uptodate(eb))) { free_pref(ref); free_extent_buffer(eb); return -EIO; } + if (lock) btrfs_tree_read_lock(eb); if (btrfs_header_level(eb) == 0) @@ -818,16 +888,11 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info, struct preftrees *preftrees, struct share_check *sc) { struct btrfs_delayed_ref_node *node; - struct btrfs_delayed_extent_op *extent_op = head->extent_op; struct btrfs_key key; - struct btrfs_key tmp_op_key; struct rb_node *n; int count; int ret = 0; - if (extent_op && extent_op->update_key) - btrfs_disk_key_to_cpu(&tmp_op_key, &extent_op->key); - spin_lock(&head->lock); for (n = rb_first_cached(&head->ref_tree); n; n = rb_next(n)) { node = rb_entry(n, struct btrfs_delayed_ref_node, @@ -852,56 +917,65 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info, switch (node->type) { case BTRFS_TREE_BLOCK_REF_KEY: { /* NORMAL INDIRECT METADATA backref */ - struct btrfs_delayed_tree_ref *ref; + struct btrfs_key *key_ptr = NULL; + /* The owner of a tree block ref is the level. */ + int level = btrfs_delayed_ref_owner(node); - ref = btrfs_delayed_node_to_tree_ref(node); - ret = add_indirect_ref(fs_info, preftrees, ref->root, - &tmp_op_key, ref->level + 1, - node->bytenr, count, sc, - GFP_ATOMIC); + if (head->extent_op && head->extent_op->update_key) { + btrfs_disk_key_to_cpu(&key, &head->extent_op->key); + key_ptr = &key; + } + + ret = add_indirect_ref(fs_info, preftrees, node->ref_root, + key_ptr, level + 1, node->bytenr, + count, sc, GFP_ATOMIC); break; } case BTRFS_SHARED_BLOCK_REF_KEY: { - /* SHARED DIRECT METADATA backref */ - struct btrfs_delayed_tree_ref *ref; - - ref = btrfs_delayed_node_to_tree_ref(node); + /* + * SHARED DIRECT METADATA backref + * + * The owner of a tree block ref is the level. + */ + int level = btrfs_delayed_ref_owner(node); - ret = add_direct_ref(fs_info, preftrees, ref->level + 1, - ref->parent, node->bytenr, count, + ret = add_direct_ref(fs_info, preftrees, level + 1, + node->parent, node->bytenr, count, sc, GFP_ATOMIC); break; } case BTRFS_EXTENT_DATA_REF_KEY: { /* NORMAL INDIRECT DATA backref */ - struct btrfs_delayed_data_ref *ref; - ref = btrfs_delayed_node_to_data_ref(node); - - key.objectid = ref->objectid; + key.objectid = btrfs_delayed_ref_owner(node); key.type = BTRFS_EXTENT_DATA_KEY; - key.offset = ref->offset; + key.offset = btrfs_delayed_ref_offset(node); /* - * Found a inum that doesn't match our known inum, we - * know it's shared. + * If we have a share check context and a reference for + * another inode, we can't exit immediately. This is + * because even if this is a BTRFS_ADD_DELAYED_REF + * reference we may find next a BTRFS_DROP_DELAYED_REF + * which cancels out this ADD reference. + * + * If this is a DROP reference and there was no previous + * ADD reference, then we need to signal that when we + * process references from the extent tree (through + * add_inline_refs() and add_keyed_refs()), we should + * not exit early if we find a reference for another + * inode, because one of the delayed DROP references + * may cancel that reference in the extent tree. */ - if (sc && sc->inum && ref->objectid != sc->inum) { - ret = BACKREF_FOUND_SHARED; - goto out; - } + if (sc && count < 0) + sc->have_delayed_delete_refs = true; - ret = add_indirect_ref(fs_info, preftrees, ref->root, + ret = add_indirect_ref(fs_info, preftrees, node->ref_root, &key, 0, node->bytenr, count, sc, GFP_ATOMIC); break; } case BTRFS_SHARED_DATA_REF_KEY: { /* SHARED DIRECT FULL backref */ - struct btrfs_delayed_data_ref *ref; - - ref = btrfs_delayed_node_to_data_ref(node); - - ret = add_direct_ref(fs_info, preftrees, 0, ref->parent, + ret = add_direct_ref(fs_info, preftrees, 0, node->parent, node->bytenr, count, sc, GFP_ATOMIC); break; @@ -918,7 +992,7 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info, } if (!ret) ret = extent_is_shared(sc); -out: + spin_unlock(&head->lock); return ret; } @@ -928,8 +1002,8 @@ out: * * Returns 0 on success, <0 on error, or BACKREF_FOUND_SHARED. */ -static int add_inline_refs(const struct btrfs_fs_info *fs_info, - struct btrfs_path *path, u64 bytenr, +static int add_inline_refs(struct btrfs_backref_walk_ctx *ctx, + struct btrfs_path *path, int *info_level, struct preftrees *preftrees, struct share_check *sc) { @@ -951,9 +1025,14 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info, slot = path->slots[0]; item_size = btrfs_item_size(leaf, slot); - BUG_ON(item_size < sizeof(*ei)); - ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); + + if (ctx->check_extent_item) { + ret = ctx->check_extent_item(ctx->bytenr, ei, leaf, ctx->user_ctx); + if (ret) + return ret; + } + flags = btrfs_extent_flags(leaf, ei); btrfs_item_key_to_cpu(leaf, &found_key, slot); @@ -982,16 +1061,16 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info, iref = (struct btrfs_extent_inline_ref *)ptr; type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY); - if (type == BTRFS_REF_TYPE_INVALID) + if (unlikely(type == BTRFS_REF_TYPE_INVALID)) return -EUCLEAN; offset = btrfs_extent_inline_ref_offset(leaf, iref); switch (type) { case BTRFS_SHARED_BLOCK_REF_KEY: - ret = add_direct_ref(fs_info, preftrees, + ret = add_direct_ref(ctx->fs_info, preftrees, *info_level + 1, offset, - bytenr, 1, NULL, GFP_NOFS); + ctx->bytenr, 1, NULL, GFP_NOFS); break; case BTRFS_SHARED_DATA_REF_KEY: { struct btrfs_shared_data_ref *sdref; @@ -1000,14 +1079,14 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info, sdref = (struct btrfs_shared_data_ref *)(iref + 1); count = btrfs_shared_data_ref_count(leaf, sdref); - ret = add_direct_ref(fs_info, preftrees, 0, offset, - bytenr, count, sc, GFP_NOFS); + ret = add_direct_ref(ctx->fs_info, preftrees, 0, offset, + ctx->bytenr, count, sc, GFP_NOFS); break; } case BTRFS_TREE_BLOCK_REF_KEY: - ret = add_indirect_ref(fs_info, preftrees, offset, + ret = add_indirect_ref(ctx->fs_info, preftrees, offset, NULL, *info_level + 1, - bytenr, 1, NULL, GFP_NOFS); + ctx->bytenr, 1, NULL, GFP_NOFS); break; case BTRFS_EXTENT_DATA_REF_KEY: { struct btrfs_extent_data_ref *dref; @@ -1021,18 +1100,25 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info, key.type = BTRFS_EXTENT_DATA_KEY; key.offset = btrfs_extent_data_ref_offset(leaf, dref); - if (sc && sc->inum && key.objectid != sc->inum) { + if (sc && key.objectid != sc->inum && + !sc->have_delayed_delete_refs) { ret = BACKREF_FOUND_SHARED; break; } root = btrfs_extent_data_ref_root(leaf, dref); - ret = add_indirect_ref(fs_info, preftrees, root, - &key, 0, bytenr, count, - sc, GFP_NOFS); + if (!ctx->skip_data_ref || + !ctx->skip_data_ref(root, key.objectid, key.offset, + ctx->user_ctx)) + ret = add_indirect_ref(ctx->fs_info, preftrees, + root, &key, 0, ctx->bytenr, + count, sc, GFP_NOFS); break; } + case BTRFS_EXTENT_OWNER_REF_KEY: + ASSERT(btrfs_fs_incompat(ctx->fs_info, SIMPLE_QUOTA)); + break; default: WARN_ON(1); } @@ -1049,8 +1135,9 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info, * * Returns 0 on success, <0 on error, or BACKREF_FOUND_SHARED. */ -static int add_keyed_refs(struct btrfs_root *extent_root, - struct btrfs_path *path, u64 bytenr, +static int add_keyed_refs(struct btrfs_backref_walk_ctx *ctx, + struct btrfs_root *extent_root, + struct btrfs_path *path, int info_level, struct preftrees *preftrees, struct share_check *sc) { @@ -1073,7 +1160,7 @@ static int add_keyed_refs(struct btrfs_root *extent_root, leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, slot); - if (key.objectid != bytenr) + if (key.objectid != ctx->bytenr) break; if (key.type < BTRFS_TREE_BLOCK_REF_KEY) continue; @@ -1085,7 +1172,7 @@ static int add_keyed_refs(struct btrfs_root *extent_root, /* SHARED DIRECT METADATA backref */ ret = add_direct_ref(fs_info, preftrees, info_level + 1, key.offset, - bytenr, 1, NULL, GFP_NOFS); + ctx->bytenr, 1, NULL, GFP_NOFS); break; case BTRFS_SHARED_DATA_REF_KEY: { /* SHARED DIRECT FULL backref */ @@ -1096,14 +1183,14 @@ static int add_keyed_refs(struct btrfs_root *extent_root, struct btrfs_shared_data_ref); count = btrfs_shared_data_ref_count(leaf, sdref); ret = add_direct_ref(fs_info, preftrees, 0, - key.offset, bytenr, count, + key.offset, ctx->bytenr, count, sc, GFP_NOFS); break; } case BTRFS_TREE_BLOCK_REF_KEY: /* NORMAL INDIRECT METADATA backref */ ret = add_indirect_ref(fs_info, preftrees, key.offset, - NULL, info_level + 1, bytenr, + NULL, info_level + 1, ctx->bytenr, 1, NULL, GFP_NOFS); break; case BTRFS_EXTENT_DATA_REF_KEY: { @@ -1120,15 +1207,20 @@ static int add_keyed_refs(struct btrfs_root *extent_root, key.type = BTRFS_EXTENT_DATA_KEY; key.offset = btrfs_extent_data_ref_offset(leaf, dref); - if (sc && sc->inum && key.objectid != sc->inum) { + if (sc && key.objectid != sc->inum && + !sc->have_delayed_delete_refs) { ret = BACKREF_FOUND_SHARED; break; } root = btrfs_extent_data_ref_root(leaf, dref); - ret = add_indirect_ref(fs_info, preftrees, root, - &key, 0, bytenr, count, - sc, GFP_NOFS); + + if (!ctx->skip_data_ref || + !ctx->skip_data_ref(root, key.objectid, key.offset, + ctx->user_ctx)) + ret = add_indirect_ref(fs_info, preftrees, root, + &key, 0, ctx->bytenr, + count, sc, GFP_NOFS); break; } default: @@ -1143,34 +1235,149 @@ static int add_keyed_refs(struct btrfs_root *extent_root, } /* + * The caller has joined a transaction or is holding a read lock on the + * fs_info->commit_root_sem semaphore, so no need to worry about the root's last + * snapshot field changing while updating or checking the cache. + */ +static bool lookup_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx, + struct btrfs_root *root, + u64 bytenr, int level, bool *is_shared) +{ + const struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_backref_shared_cache_entry *entry; + + if (!current->journal_info) + lockdep_assert_held(&fs_info->commit_root_sem); + + if (!ctx->use_path_cache) + return false; + + if (WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL)) + return false; + + /* + * Level -1 is used for the data extent, which is not reliable to cache + * because its reference count can increase or decrease without us + * realizing. We cache results only for extent buffers that lead from + * the root node down to the leaf with the file extent item. + */ + ASSERT(level >= 0); + + entry = &ctx->path_cache_entries[level]; + + /* Unused cache entry or being used for some other extent buffer. */ + if (entry->bytenr != bytenr) + return false; + + /* + * We cached a false result, but the last snapshot generation of the + * root changed, so we now have a snapshot. Don't trust the result. + */ + if (!entry->is_shared && + entry->gen != btrfs_root_last_snapshot(&root->root_item)) + return false; + + /* + * If we cached a true result and the last generation used for dropping + * a root changed, we can not trust the result, because the dropped root + * could be a snapshot sharing this extent buffer. + */ + if (entry->is_shared && + entry->gen != btrfs_get_last_root_drop_gen(fs_info)) + return false; + + *is_shared = entry->is_shared; + /* + * If the node at this level is shared, than all nodes below are also + * shared. Currently some of the nodes below may be marked as not shared + * because we have just switched from one leaf to another, and switched + * also other nodes above the leaf and below the current level, so mark + * them as shared. + */ + if (*is_shared) { + for (int i = 0; i < level; i++) { + ctx->path_cache_entries[i].is_shared = true; + ctx->path_cache_entries[i].gen = entry->gen; + } + } + + return true; +} + +/* + * The caller has joined a transaction or is holding a read lock on the + * fs_info->commit_root_sem semaphore, so no need to worry about the root's last + * snapshot field changing while updating or checking the cache. + */ +static void store_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx, + struct btrfs_root *root, + u64 bytenr, int level, bool is_shared) +{ + const struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_backref_shared_cache_entry *entry; + u64 gen; + + if (!current->journal_info) + lockdep_assert_held(&fs_info->commit_root_sem); + + if (!ctx->use_path_cache) + return; + + if (WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL)) + return; + + /* + * Level -1 is used for the data extent, which is not reliable to cache + * because its reference count can increase or decrease without us + * realizing. We cache results only for extent buffers that lead from + * the root node down to the leaf with the file extent item. + */ + ASSERT(level >= 0); + + if (is_shared) + gen = btrfs_get_last_root_drop_gen(fs_info); + else + gen = btrfs_root_last_snapshot(&root->root_item); + + entry = &ctx->path_cache_entries[level]; + entry->bytenr = bytenr; + entry->is_shared = is_shared; + entry->gen = gen; + + /* + * If we found an extent buffer is shared, set the cache result for all + * extent buffers below it to true. As nodes in the path are COWed, + * their sharedness is moved to their children, and if a leaf is COWed, + * then the sharedness of a data extent becomes direct, the refcount of + * data extent is increased in the extent item at the extent tree. + */ + if (is_shared) { + for (int i = 0; i < level; i++) { + entry = &ctx->path_cache_entries[i]; + entry->is_shared = is_shared; + entry->gen = gen; + } + } +} + +/* * this adds all existing backrefs (inline backrefs, backrefs and delayed * refs) for the given bytenr to the refs list, merges duplicates and resolves * indirect refs to their parent bytenr. * When roots are found, they're added to the roots list * - * If time_seq is set to BTRFS_SEQ_LAST, it will not search delayed_refs, and - * behave much like trans == NULL case, the difference only lies in it will not - * commit root. - * The special case is for qgroup to search roots in commit_transaction(). - * - * @sc - if !NULL, then immediately return BACKREF_FOUND_SHARED when a - * shared extent is detected. + * @ctx: Backref walking context object, must be not NULL. + * @sc: If !NULL, then immediately return BACKREF_FOUND_SHARED when a + * shared extent is detected. * * Otherwise this returns 0 for success and <0 for an error. * - * If ignore_offset is set to false, only extent refs whose offsets match - * extent_item_pos are returned. If true, every extent ref is returned - * and extent_item_pos is ignored. - * * FIXME some caching might speed things up */ -static int find_parent_nodes(struct btrfs_trans_handle *trans, - struct btrfs_fs_info *fs_info, u64 bytenr, - u64 time_seq, struct ulist *refs, - struct ulist *roots, const u64 *extent_item_pos, - struct share_check *sc, bool ignore_offset) +static int find_parent_nodes(struct btrfs_backref_walk_ctx *ctx, + struct share_check *sc) { - struct btrfs_root *root = btrfs_extent_root(fs_info, bytenr); + struct btrfs_root *root = btrfs_extent_root(ctx->fs_info, ctx->bytenr); struct btrfs_key key; struct btrfs_path *path; struct btrfs_delayed_ref_root *delayed_refs = NULL; @@ -1186,23 +1393,27 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans, .indirect_missing_keys = PREFTREE_INIT }; - key.objectid = bytenr; - key.offset = (u64)-1; - if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) + /* Roots ulist is not needed when using a sharedness check context. */ + if (sc) + ASSERT(ctx->roots == NULL); + + key.objectid = ctx->bytenr; + if (btrfs_fs_incompat(ctx->fs_info, SKINNY_METADATA)) key.type = BTRFS_METADATA_ITEM_KEY; else key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = (u64)-1; path = btrfs_alloc_path(); if (!path) return -ENOMEM; - if (!trans) { - path->search_commit_root = 1; - path->skip_locking = 1; + if (!ctx->trans) { + path->search_commit_root = true; + path->skip_locking = true; } - if (time_seq == BTRFS_SEQ_LAST) - path->skip_locking = 1; + if (ctx->time_seq == BTRFS_SEQ_LAST) + path->skip_locking = true; again: head = NULL; @@ -1210,24 +1421,27 @@ again: ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; - if (ret == 0) { - /* This shouldn't happen, indicates a bug or fs corruption. */ - ASSERT(ret != 0); + if (unlikely(ret == 0)) { + /* + * Key with offset -1 found, there would have to exist an extent + * item with such offset, but this is out of the valid range. + */ ret = -EUCLEAN; goto out; } - if (trans && likely(trans->type != __TRANS_DUMMY) && - time_seq != BTRFS_SEQ_LAST) { + if (ctx->trans && likely(ctx->trans->type != __TRANS_DUMMY) && + ctx->time_seq != BTRFS_SEQ_LAST) { /* * We have a specific time_seq we care about and trans which * means we have the path lock, we need to grab the ref head and * lock it so we have a consistent view of the refs at the given * time. */ - delayed_refs = &trans->transaction->delayed_refs; + delayed_refs = &ctx->trans->transaction->delayed_refs; spin_lock(&delayed_refs->lock); - head = btrfs_find_delayed_ref_head(delayed_refs, bytenr); + head = btrfs_find_delayed_ref_head(ctx->fs_info, delayed_refs, + ctx->bytenr); if (head) { if (!mutex_trylock(&head->mutex)) { refcount_inc(&head->refs); @@ -1245,7 +1459,7 @@ again: goto again; } spin_unlock(&delayed_refs->lock); - ret = add_delayed_refs(fs_info, head, time_seq, + ret = add_delayed_refs(ctx->fs_info, head, ctx->time_seq, &preftrees, sc); mutex_unlock(&head->mutex); if (ret) @@ -1263,30 +1477,96 @@ again: leaf = path->nodes[0]; slot = path->slots[0]; btrfs_item_key_to_cpu(leaf, &key, slot); - if (key.objectid == bytenr && + if (key.objectid == ctx->bytenr && (key.type == BTRFS_EXTENT_ITEM_KEY || key.type == BTRFS_METADATA_ITEM_KEY)) { - ret = add_inline_refs(fs_info, path, bytenr, - &info_level, &preftrees, sc); + ret = add_inline_refs(ctx, path, &info_level, + &preftrees, sc); if (ret) goto out; - ret = add_keyed_refs(root, path, bytenr, info_level, + ret = add_keyed_refs(ctx, root, path, info_level, &preftrees, sc); if (ret) goto out; } } + /* + * If we have a share context and we reached here, it means the extent + * is not directly shared (no multiple reference items for it), + * otherwise we would have exited earlier with a return value of + * BACKREF_FOUND_SHARED after processing delayed references or while + * processing inline or keyed references from the extent tree. + * The extent may however be indirectly shared through shared subtrees + * as a result from creating snapshots, so we determine below what is + * its parent node, in case we are dealing with a metadata extent, or + * what's the leaf (or leaves), from a fs tree, that has a file extent + * item pointing to it in case we are dealing with a data extent. + */ + ASSERT(extent_is_shared(sc) == 0); + + /* + * If we are here for a data extent and we have a share_check structure + * it means the data extent is not directly shared (does not have + * multiple reference items), so we have to check if a path in the fs + * tree (going from the root node down to the leaf that has the file + * extent item pointing to the data extent) is shared, that is, if any + * of the extent buffers in the path is referenced by other trees. + */ + if (sc && ctx->bytenr == sc->data_bytenr) { + /* + * If our data extent is from a generation more recent than the + * last generation used to snapshot the root, then we know that + * it can not be shared through subtrees, so we can skip + * resolving indirect references, there's no point in + * determining the extent buffers for the path from the fs tree + * root node down to the leaf that has the file extent item that + * points to the data extent. + */ + if (sc->data_extent_gen > + btrfs_root_last_snapshot(&sc->root->root_item)) { + ret = BACKREF_FOUND_NOT_SHARED; + goto out; + } + + /* + * If we are only determining if a data extent is shared or not + * and the corresponding file extent item is located in the same + * leaf as the previous file extent item, we can skip resolving + * indirect references for a data extent, since the fs tree path + * is the same (same leaf, so same path). We skip as long as the + * cached result for the leaf is valid and only if there's only + * one file extent item pointing to the data extent, because in + * the case of multiple file extent items, they may be located + * in different leaves and therefore we have multiple paths. + */ + if (sc->ctx->curr_leaf_bytenr == sc->ctx->prev_leaf_bytenr && + sc->self_ref_count == 1) { + bool cached; + bool is_shared; + + cached = lookup_backref_shared_cache(sc->ctx, sc->root, + sc->ctx->curr_leaf_bytenr, + 0, &is_shared); + if (cached) { + if (is_shared) + ret = BACKREF_FOUND_SHARED; + else + ret = BACKREF_FOUND_NOT_SHARED; + goto out; + } + } + } + btrfs_release_path(path); - ret = add_missing_keys(fs_info, &preftrees, path->skip_locking == 0); + ret = add_missing_keys(ctx->fs_info, &preftrees, !path->skip_locking); if (ret) goto out; WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect_missing_keys.root.rb_root)); - ret = resolve_indirect_refs(fs_info, path, time_seq, &preftrees, - extent_item_pos, sc, ignore_offset); + ret = resolve_indirect_refs(ctx, path, &preftrees, sc); if (ret) goto out; @@ -1313,29 +1593,27 @@ again: * e.g. different offsets would not be merged, * and would retain their original ref->count < 0. */ - if (roots && ref->count && ref->root_id && ref->parent == 0) { - if (sc && sc->root_objectid && - ref->root_id != sc->root_objectid) { - ret = BACKREF_FOUND_SHARED; - goto out; - } - + if (ctx->roots && ref->count && ref->root_id && ref->parent == 0) { /* no parent == root of tree */ - ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); + ret = ulist_add(ctx->roots, ref->root_id, 0, GFP_NOFS); if (ret < 0) goto out; } if (ref->count && ref->parent) { - if (extent_item_pos && !ref->inode_list && + if (!ctx->skip_inode_ref_list && !ref->inode_list && ref->level == 0) { + struct btrfs_tree_parent_check check = { 0 }; struct extent_buffer *eb; - eb = read_tree_block(fs_info, ref->parent, 0, - 0, ref->level, NULL); + check.level = ref->level; + + eb = read_tree_block(ctx->fs_info, ref->parent, + &check); if (IS_ERR(eb)) { ret = PTR_ERR(eb); goto out; - } else if (!extent_buffer_uptodate(eb)) { + } + if (unlikely(!extent_buffer_uptodate(eb))) { free_extent_buffer(eb); ret = -EIO; goto out; @@ -1343,21 +1621,27 @@ again: if (!path->skip_locking) btrfs_tree_read_lock(eb); - ret = find_extent_in_eb(eb, bytenr, - *extent_item_pos, &eie, ignore_offset); + ret = find_extent_in_eb(ctx, eb, &eie); if (!path->skip_locking) btrfs_tree_read_unlock(eb); free_extent_buffer(eb); - if (ret < 0) + if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || + ret < 0) goto out; ref->inode_list = eie; + /* + * We transferred the list ownership to the ref, + * so set to NULL to avoid a double free in case + * an error happens after this. + */ + eie = NULL; } - ret = ulist_add_merge_ptr(refs, ref->parent, + ret = ulist_add_merge_ptr(ctx->refs, ref->parent, ref->inode_list, (void **)&eie, GFP_NOFS); if (ret < 0) goto out; - if (!ret && extent_item_pos) { + if (!ret && !ctx->skip_inode_ref_list) { /* * We've recorded that parent, so we must extend * its inode list here. @@ -1367,7 +1651,7 @@ again: * case. */ ASSERT(eie); - if (!eie) { + if (unlikely(!eie)) { ret = -EUCLEAN; goto out; } @@ -1376,6 +1660,14 @@ again: eie->next = ref->inode_list; } eie = NULL; + /* + * We have transferred the inode list ownership from + * this ref to the ref we added to the 'refs' ulist. + * So set this ref's inode list to NULL to avoid + * use-after-free when our caller uses it or double + * frees in case an error happens before we return. + */ + ref->inode_list = NULL; } cond_resched(); } @@ -1387,52 +1679,36 @@ out: prelim_release(&preftrees.indirect); prelim_release(&preftrees.indirect_missing_keys); - if (ret < 0) + if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || ret < 0) free_inode_elem_list(eie); return ret; } -static void free_leaf_list(struct ulist *blocks) -{ - struct ulist_node *node = NULL; - struct extent_inode_elem *eie; - struct ulist_iterator uiter; - - ULIST_ITER_INIT(&uiter); - while ((node = ulist_next(blocks, &uiter))) { - if (!node->aux) - continue; - eie = unode_aux_to_inode_list(node); - free_inode_elem_list(eie); - node->aux = 0; - } - - ulist_free(blocks); -} - /* - * Finds all leafs with a reference to the specified combination of bytenr and - * offset. key_list_head will point to a list of corresponding keys (caller must - * free each list element). The leafs will be stored in the leafs ulist, which - * must be freed with ulist_free. + * Finds all leaves with a reference to the specified combination of + * @ctx->bytenr and @ctx->extent_item_pos. The bytenr of the found leaves are + * added to the ulist at @ctx->refs, and that ulist is allocated by this + * function. The caller should free the ulist with free_leaf_list() if + * @ctx->ignore_extent_item_pos is false, otherwise a simple ulist_free() is + * enough. * - * returns 0 on success, <0 on error + * Returns 0 on success and < 0 on error. On error @ctx->refs is not allocated. */ -int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, - struct btrfs_fs_info *fs_info, u64 bytenr, - u64 time_seq, struct ulist **leafs, - const u64 *extent_item_pos, bool ignore_offset) +int btrfs_find_all_leafs(struct btrfs_backref_walk_ctx *ctx) { int ret; - *leafs = ulist_alloc(GFP_NOFS); - if (!*leafs) + ASSERT(ctx->refs == NULL); + + ctx->refs = ulist_alloc(GFP_NOFS); + if (!ctx->refs) return -ENOMEM; - ret = find_parent_nodes(trans, fs_info, bytenr, time_seq, - *leafs, NULL, extent_item_pos, NULL, ignore_offset); - if (ret < 0 && ret != -ENOENT) { - free_leaf_list(*leafs); + ret = find_parent_nodes(ctx, NULL); + if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP || + (ret < 0 && ret != -ENOENT)) { + free_leaf_list(ctx->refs); + ctx->refs = NULL; return ret; } @@ -1440,7 +1716,7 @@ int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, } /* - * walk all backrefs for a given extent to find all roots that reference this + * Walk all backrefs for a given extent to find all roots that reference this * extent. Walking a backref means finding all extents that reference this * extent and in turn walk the backrefs of those, too. Naturally this is a * recursive process, but here it is implemented in an iterative fashion: We @@ -1448,76 +1724,115 @@ int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, * list. In turn, we find all referencing extents for those, further appending * to the list. The way we iterate the list allows adding more elements after * the current while iterating. The process stops when we reach the end of the - * list. Found roots are added to the roots list. + * list. * - * returns 0 on success, < 0 on error. + * Found roots are added to @ctx->roots, which is allocated by this function if + * it points to NULL, in which case the caller is responsible for freeing it + * after it's not needed anymore. + * This function requires @ctx->refs to be NULL, as it uses it for allocating a + * ulist to do temporary work, and frees it before returning. + * + * Returns 0 on success, < 0 on error. */ -static int btrfs_find_all_roots_safe(struct btrfs_trans_handle *trans, - struct btrfs_fs_info *fs_info, u64 bytenr, - u64 time_seq, struct ulist **roots, - bool ignore_offset) +static int btrfs_find_all_roots_safe(struct btrfs_backref_walk_ctx *ctx) { - struct ulist *tmp; - struct ulist_node *node = NULL; + const u64 orig_bytenr = ctx->bytenr; + const bool orig_skip_inode_ref_list = ctx->skip_inode_ref_list; + bool roots_ulist_allocated = false; struct ulist_iterator uiter; - int ret; + int ret = 0; - tmp = ulist_alloc(GFP_NOFS); - if (!tmp) - return -ENOMEM; - *roots = ulist_alloc(GFP_NOFS); - if (!*roots) { - ulist_free(tmp); + ASSERT(ctx->refs == NULL); + + ctx->refs = ulist_alloc(GFP_NOFS); + if (!ctx->refs) return -ENOMEM; + + if (!ctx->roots) { + ctx->roots = ulist_alloc(GFP_NOFS); + if (!ctx->roots) { + ulist_free(ctx->refs); + ctx->refs = NULL; + return -ENOMEM; + } + roots_ulist_allocated = true; } + ctx->skip_inode_ref_list = true; + ULIST_ITER_INIT(&uiter); while (1) { - ret = find_parent_nodes(trans, fs_info, bytenr, time_seq, - tmp, *roots, NULL, NULL, ignore_offset); + struct ulist_node *node; + + ret = find_parent_nodes(ctx, NULL); if (ret < 0 && ret != -ENOENT) { - ulist_free(tmp); - ulist_free(*roots); - *roots = NULL; - return ret; + if (roots_ulist_allocated) { + ulist_free(ctx->roots); + ctx->roots = NULL; + } + break; } - node = ulist_next(tmp, &uiter); + ret = 0; + node = ulist_next(ctx->refs, &uiter); if (!node) break; - bytenr = node->val; + ctx->bytenr = node->val; cond_resched(); } - ulist_free(tmp); - return 0; + ulist_free(ctx->refs); + ctx->refs = NULL; + ctx->bytenr = orig_bytenr; + ctx->skip_inode_ref_list = orig_skip_inode_ref_list; + + return ret; } -int btrfs_find_all_roots(struct btrfs_trans_handle *trans, - struct btrfs_fs_info *fs_info, u64 bytenr, - u64 time_seq, struct ulist **roots, +int btrfs_find_all_roots(struct btrfs_backref_walk_ctx *ctx, bool skip_commit_root_sem) { int ret; - if (!trans && !skip_commit_root_sem) - down_read(&fs_info->commit_root_sem); - ret = btrfs_find_all_roots_safe(trans, fs_info, bytenr, - time_seq, roots, false); - if (!trans && !skip_commit_root_sem) - up_read(&fs_info->commit_root_sem); + if (!ctx->trans && !skip_commit_root_sem) + down_read(&ctx->fs_info->commit_root_sem); + ret = btrfs_find_all_roots_safe(ctx); + if (!ctx->trans && !skip_commit_root_sem) + up_read(&ctx->fs_info->commit_root_sem); return ret; } -/** - * Check if an extent is shared or not +struct btrfs_backref_share_check_ctx *btrfs_alloc_backref_share_check_ctx(void) +{ + struct btrfs_backref_share_check_ctx *ctx; + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return NULL; + + ulist_init(&ctx->refs); + + return ctx; +} + +void btrfs_free_backref_share_ctx(struct btrfs_backref_share_check_ctx *ctx) +{ + if (!ctx) + return; + + ulist_release(&ctx->refs); + kfree(ctx); +} + +/* + * Check if a data extent is shared or not. * - * @root: root inode belongs to - * @inum: inode number of the inode whose extent we are checking - * @bytenr: logical bytenr of the extent we are checking - * @roots: list of roots this extent is shared among - * @tmp: temporary list used for iteration + * @inode: The inode whose extent we are checking. + * @bytenr: Logical bytenr of the extent we are checking. + * @extent_gen: Generation of the extent (file extent item) or 0 if it is + * not known. + * @ctx: A backref sharedness check context. * - * btrfs_check_shared uses the backref walking code but will short + * btrfs_is_data_extent_shared uses the backref walking code but will short * circuit as soon as it finds a root or inode that doesn't match the * one passed in. This provides a significant performance benefit for * callers (such as fiemap) which want to know whether the extent is @@ -1528,9 +1843,12 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans, * * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error. */ -int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr, - struct ulist *roots, struct ulist *tmp) +int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr, + u64 extent_gen, + struct btrfs_backref_share_check_ctx *ctx) { + struct btrfs_backref_walk_ctx walk_ctx = { 0 }; + struct btrfs_root *root = inode->root; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_trans_handle *trans; struct ulist_iterator uiter; @@ -1538,13 +1856,25 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr, struct btrfs_seq_list elem = BTRFS_SEQ_LIST_INIT(elem); int ret = 0; struct share_check shared = { - .root_objectid = root->root_key.objectid, - .inum = inum, + .ctx = ctx, + .root = root, + .inum = btrfs_ino(inode), + .data_bytenr = bytenr, + .data_extent_gen = extent_gen, .share_count = 0, + .self_ref_count = 0, + .have_delayed_delete_refs = false, }; + int level; + bool leaf_cached; + bool leaf_is_shared; + + for (int i = 0; i < BTRFS_BACKREF_CTX_PREV_EXTENTS_SIZE; i++) { + if (ctx->prev_extents_cache[i].bytenr == bytenr) + return ctx->prev_extents_cache[i].is_shared; + } - ulist_init(roots); - ulist_init(tmp); + ulist_init(&ctx->refs); trans = btrfs_join_transaction_nostart(root); if (IS_ERR(trans)) { @@ -1556,28 +1886,146 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr, down_read(&fs_info->commit_root_sem); } else { btrfs_get_tree_mod_seq(fs_info, &elem); + walk_ctx.time_seq = elem.seq; } + ctx->use_path_cache = true; + + /* + * We may have previously determined that the current leaf is shared. + * If it is, then we have a data extent that is shared due to a shared + * subtree (caused by snapshotting) and we don't need to check for data + * backrefs. If the leaf is not shared, then we must do backref walking + * to determine if the data extent is shared through reflinks. + */ + leaf_cached = lookup_backref_shared_cache(ctx, root, + ctx->curr_leaf_bytenr, 0, + &leaf_is_shared); + if (leaf_cached && leaf_is_shared) { + ret = 1; + goto out_trans; + } + + walk_ctx.skip_inode_ref_list = true; + walk_ctx.trans = trans; + walk_ctx.fs_info = fs_info; + walk_ctx.refs = &ctx->refs; + + /* -1 means we are in the bytenr of the data extent. */ + level = -1; ULIST_ITER_INIT(&uiter); while (1) { - ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp, - roots, NULL, &shared, false); - if (ret == BACKREF_FOUND_SHARED) { - /* this is the only condition under which we return 1 */ - ret = 1; + const unsigned long prev_ref_count = ctx->refs.nnodes; + + walk_ctx.bytenr = bytenr; + ret = find_parent_nodes(&walk_ctx, &shared); + if (ret == BACKREF_FOUND_SHARED || + ret == BACKREF_FOUND_NOT_SHARED) { + /* If shared must return 1, otherwise return 0. */ + ret = (ret == BACKREF_FOUND_SHARED) ? 1 : 0; + if (level >= 0) + store_backref_shared_cache(ctx, root, bytenr, + level, ret == 1); break; } if (ret < 0 && ret != -ENOENT) break; ret = 0; - node = ulist_next(tmp, &uiter); + + /* + * More than one extent buffer (bytenr) may have been added to + * the ctx->refs ulist, in which case we have to check multiple + * tree paths in case the first one is not shared, so we can not + * use the path cache which is made for a single path. Multiple + * extent buffers at the current level happen when: + * + * 1) level -1, the data extent: If our data extent was not + * directly shared (without multiple reference items), then + * it might have a single reference item with a count > 1 for + * the same offset, which means there are 2 (or more) file + * extent items that point to the data extent - this happens + * when a file extent item needs to be split and then one + * item gets moved to another leaf due to a b+tree leaf split + * when inserting some item. In this case the file extent + * items may be located in different leaves and therefore + * some of the leaves may be referenced through shared + * subtrees while others are not. Since our extent buffer + * cache only works for a single path (by far the most common + * case and simpler to deal with), we can not use it if we + * have multiple leaves (which implies multiple paths). + * + * 2) level >= 0, a tree node/leaf: We can have a mix of direct + * and indirect references on a b+tree node/leaf, so we have + * to check multiple paths, and the extent buffer (the + * current bytenr) may be shared or not. One example is + * during relocation as we may get a shared tree block ref + * (direct ref) and a non-shared tree block ref (indirect + * ref) for the same node/leaf. + */ + if ((ctx->refs.nnodes - prev_ref_count) > 1) + ctx->use_path_cache = false; + + if (level >= 0) + store_backref_shared_cache(ctx, root, bytenr, + level, false); + node = ulist_next(&ctx->refs, &uiter); if (!node) break; bytenr = node->val; + if (ctx->use_path_cache) { + bool is_shared; + bool cached; + + level++; + cached = lookup_backref_shared_cache(ctx, root, bytenr, + level, &is_shared); + if (cached) { + ret = (is_shared ? 1 : 0); + break; + } + } shared.share_count = 0; + shared.have_delayed_delete_refs = false; cond_resched(); } + /* + * If the path cache is disabled, then it means at some tree level we + * got multiple parents due to a mix of direct and indirect backrefs or + * multiple leaves with file extent items pointing to the same data + * extent. We have to invalidate the cache and cache only the sharedness + * result for the levels where we got only one node/reference. + */ + if (!ctx->use_path_cache) { + int i = 0; + + level--; + if (ret >= 0 && level >= 0) { + bytenr = ctx->path_cache_entries[level].bytenr; + ctx->use_path_cache = true; + store_backref_shared_cache(ctx, root, bytenr, level, ret); + i = level + 1; + } + + for ( ; i < BTRFS_MAX_LEVEL; i++) + ctx->path_cache_entries[i].bytenr = 0; + } + + /* + * Cache the sharedness result for the data extent if we know our inode + * has more than 1 file extent item that refers to the data extent. + */ + if (ret >= 0 && shared.self_ref_count > 1) { + int slot = ctx->prev_extents_cache_slot; + + ctx->prev_extents_cache[slot].bytenr = shared.data_bytenr; + ctx->prev_extents_cache[slot].is_shared = (ret == 1); + + slot = (slot + 1) % BTRFS_BACKREF_CTX_PREV_EXTENTS_SIZE; + ctx->prev_extents_cache_slot = slot; + } + +out_trans: if (trans) { btrfs_put_tree_mod_seq(fs_info, &elem); btrfs_end_transaction(trans); @@ -1585,8 +2033,9 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr, up_read(&fs_info->commit_root_sem); } out: - ulist_release(roots); - ulist_release(tmp); + ulist_release(&ctx->refs); + ctx->prev_leaf_bytenr = ctx->curr_leaf_bytenr; + return ret; } @@ -1751,21 +2200,27 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, int ret; u64 flags; u64 size = 0; - u32 item_size; const struct extent_buffer *eb; struct btrfs_extent_item *ei; struct btrfs_key key; + key.objectid = logical; if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) key.type = BTRFS_METADATA_ITEM_KEY; else key.type = BTRFS_EXTENT_ITEM_KEY; - key.objectid = logical; key.offset = (u64)-1; ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0); if (ret < 0) return ret; + if (unlikely(ret == 0)) { + /* + * Key with offset -1 found, there would have to exist an extent + * item with such offset, but this is out of the valid range. + */ + return -EUCLEAN; + } ret = btrfs_previous_extent_item(extent_root, path, 0); if (ret) { @@ -1787,8 +2242,6 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, } eb = path->nodes[0]; - item_size = btrfs_item_size(eb, path->slots[0]); - BUG_ON(item_size < sizeof(*ei)); ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); flags = btrfs_extent_flags(eb, ei); @@ -1796,7 +2249,7 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, btrfs_debug(fs_info, "logical %llu is at position %llu within the extent (%llu EXTENT_ITEM %llu) flags %#llx size %u", logical, logical - found_key->objectid, found_key->objectid, - found_key->offset, flags, item_size); + found_key->offset, flags, btrfs_item_size(eb, path->slots[0])); WARN_ON(!flags_ret); if (flags_ret) { @@ -1858,7 +2311,7 @@ static int get_extent_inline_ref(unsigned long *ptr, *out_eiref = (struct btrfs_extent_inline_ref *)(*ptr); *out_type = btrfs_get_extent_inline_ref_type(eb, *out_eiref, BTRFS_REF_TYPE_ANY); - if (*out_type == BTRFS_REF_TYPE_INVALID) + if (unlikely(*out_type == BTRFS_REF_TYPE_INVALID)) return -EUCLEAN; *ptr += btrfs_extent_inline_ref_size(*out_type); @@ -1933,7 +2386,7 @@ static int iterate_leaf_refs(struct btrfs_fs_info *fs_info, "ref for %llu resolved, key (%llu EXTEND_DATA %llu), root %llu", extent_item_objectid, eie->inum, eie->offset, root); - ret = iterate(eie->inum, eie->offset, root, ctx); + ret = iterate(eie->inum, eie->offset, eie->num_bytes, root, ctx); if (ret) { btrfs_debug(fs_info, "stopping iteration for %llu due to ret=%d", @@ -1950,113 +2403,181 @@ static int iterate_leaf_refs(struct btrfs_fs_info *fs_info, * the given parameters. * when the iterator function returns a non-zero value, iteration stops. */ -int iterate_extent_inodes(struct btrfs_fs_info *fs_info, - u64 extent_item_objectid, u64 extent_item_pos, - int search_commit_root, - iterate_extent_inodes_t *iterate, void *ctx, - bool ignore_offset) +int iterate_extent_inodes(struct btrfs_backref_walk_ctx *ctx, + bool search_commit_root, + iterate_extent_inodes_t *iterate, void *user_ctx) { int ret; - struct btrfs_trans_handle *trans = NULL; - struct ulist *refs = NULL; - struct ulist *roots = NULL; - struct ulist_node *ref_node = NULL; - struct ulist_node *root_node = NULL; + struct ulist *refs; + struct ulist_node *ref_node; struct btrfs_seq_list seq_elem = BTRFS_SEQ_LIST_INIT(seq_elem); struct ulist_iterator ref_uiter; - struct ulist_iterator root_uiter; - btrfs_debug(fs_info, "resolving all inodes for extent %llu", - extent_item_objectid); + btrfs_debug(ctx->fs_info, "resolving all inodes for extent %llu", + ctx->bytenr); + + ASSERT(ctx->trans == NULL); + ASSERT(ctx->roots == NULL); if (!search_commit_root) { - trans = btrfs_attach_transaction(fs_info->tree_root); + struct btrfs_trans_handle *trans; + + trans = btrfs_attach_transaction(ctx->fs_info->tree_root); if (IS_ERR(trans)) { if (PTR_ERR(trans) != -ENOENT && PTR_ERR(trans) != -EROFS) return PTR_ERR(trans); trans = NULL; } + ctx->trans = trans; } - if (trans) - btrfs_get_tree_mod_seq(fs_info, &seq_elem); - else - down_read(&fs_info->commit_root_sem); + if (ctx->trans) { + btrfs_get_tree_mod_seq(ctx->fs_info, &seq_elem); + ctx->time_seq = seq_elem.seq; + } else { + down_read(&ctx->fs_info->commit_root_sem); + } - ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, - seq_elem.seq, &refs, - &extent_item_pos, ignore_offset); + ret = btrfs_find_all_leafs(ctx); if (ret) goto out; + refs = ctx->refs; + ctx->refs = NULL; ULIST_ITER_INIT(&ref_uiter); while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) { - ret = btrfs_find_all_roots_safe(trans, fs_info, ref_node->val, - seq_elem.seq, &roots, - ignore_offset); + const u64 leaf_bytenr = ref_node->val; + struct ulist_node *root_node; + struct ulist_iterator root_uiter; + struct extent_inode_elem *inode_list; + + inode_list = (struct extent_inode_elem *)(uintptr_t)ref_node->aux; + + if (ctx->cache_lookup) { + const u64 *root_ids; + int root_count; + bool cached; + + cached = ctx->cache_lookup(leaf_bytenr, ctx->user_ctx, + &root_ids, &root_count); + if (cached) { + for (int i = 0; i < root_count; i++) { + ret = iterate_leaf_refs(ctx->fs_info, + inode_list, + root_ids[i], + leaf_bytenr, + iterate, + user_ctx); + if (ret) + break; + } + continue; + } + } + + if (!ctx->roots) { + ctx->roots = ulist_alloc(GFP_NOFS); + if (!ctx->roots) { + ret = -ENOMEM; + break; + } + } + + ctx->bytenr = leaf_bytenr; + ret = btrfs_find_all_roots_safe(ctx); if (ret) break; + + if (ctx->cache_store) + ctx->cache_store(leaf_bytenr, ctx->roots, ctx->user_ctx); + ULIST_ITER_INIT(&root_uiter); - while (!ret && (root_node = ulist_next(roots, &root_uiter))) { - btrfs_debug(fs_info, + while (!ret && (root_node = ulist_next(ctx->roots, &root_uiter))) { + btrfs_debug(ctx->fs_info, "root %llu references leaf %llu, data list %#llx", root_node->val, ref_node->val, ref_node->aux); - ret = iterate_leaf_refs(fs_info, - (struct extent_inode_elem *) - (uintptr_t)ref_node->aux, - root_node->val, - extent_item_objectid, - iterate, ctx); + ret = iterate_leaf_refs(ctx->fs_info, inode_list, + root_node->val, ctx->bytenr, + iterate, user_ctx); } - ulist_free(roots); + ulist_reinit(ctx->roots); } free_leaf_list(refs); out: - if (trans) { - btrfs_put_tree_mod_seq(fs_info, &seq_elem); - btrfs_end_transaction(trans); + if (ctx->trans) { + btrfs_put_tree_mod_seq(ctx->fs_info, &seq_elem); + btrfs_end_transaction(ctx->trans); + ctx->trans = NULL; } else { - up_read(&fs_info->commit_root_sem); + up_read(&ctx->fs_info->commit_root_sem); } + ulist_free(ctx->roots); + ctx->roots = NULL; + + if (ret == BTRFS_ITERATE_EXTENT_INODES_STOP) + ret = 0; + return ret; } +static int build_ino_list(u64 inum, u64 offset, u64 num_bytes, u64 root, void *ctx) +{ + struct btrfs_data_container *inodes = ctx; + const size_t c = 3 * sizeof(u64); + + if (inodes->bytes_left >= c) { + inodes->bytes_left -= c; + inodes->val[inodes->elem_cnt] = inum; + inodes->val[inodes->elem_cnt + 1] = offset; + inodes->val[inodes->elem_cnt + 2] = root; + inodes->elem_cnt += 3; + } else { + inodes->bytes_missing += c - inodes->bytes_left; + inodes->bytes_left = 0; + inodes->elem_missed += 3; + } + + return 0; +} + int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, - struct btrfs_path *path, - iterate_extent_inodes_t *iterate, void *ctx, - bool ignore_offset) + void *ctx, bool ignore_offset) { + struct btrfs_backref_walk_ctx walk_ctx = { 0 }; int ret; - u64 extent_item_pos; u64 flags = 0; struct btrfs_key found_key; - int search_commit_root = path->search_commit_root; + struct btrfs_path *path; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; ret = extent_from_logical(fs_info, logical, path, &found_key, &flags); - btrfs_release_path(path); + btrfs_free_path(path); if (ret < 0) return ret; if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) return -EINVAL; - extent_item_pos = logical - found_key.objectid; - ret = iterate_extent_inodes(fs_info, found_key.objectid, - extent_item_pos, search_commit_root, - iterate, ctx, ignore_offset); + walk_ctx.bytenr = found_key.objectid; + if (ignore_offset) + walk_ctx.ignore_extent_item_pos = true; + else + walk_ctx.extent_item_pos = logical - found_key.objectid; + walk_ctx.fs_info = fs_info; - return ret; + return iterate_extent_inodes(&walk_ctx, false, build_ino_list, ctx); } -typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off, - struct extent_buffer *eb, void *ctx); +static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off, + struct extent_buffer *eb, struct inode_fs_paths *ipath); -static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root, - struct btrfs_path *path, - iterate_irefs_t *iterate, void *ctx) +static int iterate_inode_refs(u64 inum, struct inode_fs_paths *ipath) { int ret = 0; int slot; @@ -2065,6 +2586,8 @@ static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root, u32 name_len; u64 parent = 0; int found = 0; + struct btrfs_root *fs_root = ipath->fs_root; + struct btrfs_path *path = ipath->btrfs_path; struct extent_buffer *eb; struct btrfs_inode_ref *iref; struct btrfs_key found_key; @@ -2099,9 +2622,9 @@ static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root, btrfs_debug(fs_root->fs_info, "following ref at offset %u for inode %llu in tree %llu", cur, found_key.objectid, - fs_root->root_key.objectid); - ret = iterate(parent, name_len, - (unsigned long)(iref + 1), eb, ctx); + btrfs_root_id(fs_root)); + ret = inode_to_path(parent, name_len, + (unsigned long)(iref + 1), eb, ipath); if (ret) break; len = sizeof(*iref) + name_len; @@ -2115,15 +2638,15 @@ static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root, return ret; } -static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, - struct btrfs_path *path, - iterate_irefs_t *iterate, void *ctx) +static int iterate_inode_extrefs(u64 inum, struct inode_fs_paths *ipath) { int ret; int slot; u64 offset = 0; u64 parent; int found = 0; + struct btrfs_root *fs_root = ipath->fs_root; + struct btrfs_path *path = ipath->btrfs_path; struct extent_buffer *eb; struct btrfs_inode_extref *extref; u32 item_size; @@ -2159,8 +2682,8 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, extref = (struct btrfs_inode_extref *)(ptr + cur_offset); parent = btrfs_inode_extref_parent(eb, extref); name_len = btrfs_inode_extref_name_len(eb, extref); - ret = iterate(parent, name_len, - (unsigned long)&extref->name, eb, ctx); + ret = inode_to_path(parent, name_len, + (unsigned long)&extref->name, eb, ipath); if (ret) break; @@ -2177,34 +2700,13 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, return ret; } -static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, - struct btrfs_path *path, iterate_irefs_t *iterate, - void *ctx) -{ - int ret; - int found_refs = 0; - - ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx); - if (!ret) - ++found_refs; - else if (ret != -ENOENT) - return ret; - - ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx); - if (ret == -ENOENT && found_refs) - return 0; - - return ret; -} - /* * returns 0 if the path could be dumped (probably truncated) * returns <0 in case of an error */ static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off, - struct extent_buffer *eb, void *ctx) + struct extent_buffer *eb, struct inode_fs_paths *ipath) { - struct inode_fs_paths *ipath = ctx; char *fspath; char *fspath_min; int i = ipath->fspath->elem_cnt; @@ -2245,8 +2747,20 @@ static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off, */ int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) { - return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, - inode_to_path, ipath); + int ret; + int found_refs = 0; + + ret = iterate_inode_refs(inum, ipath); + if (!ret) + ++found_refs; + else if (ret != -ENOENT) + return ret; + + ret = iterate_inode_extrefs(inum, ipath); + if (ret == -ENOENT && found_refs) + return 0; + + return ret; } struct btrfs_data_container *init_data_container(u32 total_bytes) @@ -2255,20 +2769,14 @@ struct btrfs_data_container *init_data_container(u32 total_bytes) size_t alloc_bytes; alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); - data = kvmalloc(alloc_bytes, GFP_KERNEL); + data = kvzalloc(alloc_bytes, GFP_KERNEL); if (!data) return ERR_PTR(-ENOMEM); - if (total_bytes >= sizeof(*data)) { + if (total_bytes >= sizeof(*data)) data->bytes_left = total_bytes - sizeof(*data); - data->bytes_missing = 0; - } else { + else data->bytes_missing = sizeof(*data) - total_bytes; - data->bytes_left = 0; - } - - data->elem_cnt = 0; - data->elem_missed = 0; return data; } @@ -2277,7 +2785,7 @@ struct btrfs_data_container *init_data_container(u32 total_bytes) * allocates space to return multiple file system paths for an inode. * total_bytes to allocate are passed, note that space usable for actual path * information will be total_bytes - sizeof(struct inode_fs_paths). - * the returned pointer must be freed with free_ipath() in the end. + * the returned pointer must be freed with __free_inode_fs_paths() in the end. */ struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, struct btrfs_path *path) @@ -2302,20 +2810,11 @@ struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, return ifp; } -void free_ipath(struct inode_fs_paths *ipath) -{ - if (!ipath) - return; - kvfree(ipath->fspath); - kfree(ipath); -} - -struct btrfs_backref_iter *btrfs_backref_iter_alloc( - struct btrfs_fs_info *fs_info, gfp_t gfp_flag) +struct btrfs_backref_iter *btrfs_backref_iter_alloc(struct btrfs_fs_info *fs_info) { struct btrfs_backref_iter *ret; - ret = kzalloc(sizeof(*ret), gfp_flag); + ret = kzalloc(sizeof(*ret), GFP_NOFS); if (!ret) return NULL; @@ -2326,13 +2825,23 @@ struct btrfs_backref_iter *btrfs_backref_iter_alloc( } /* Current backref iterator only supports iteration in commit root */ - ret->path->search_commit_root = 1; - ret->path->skip_locking = 1; + ret->path->search_commit_root = true; + ret->path->skip_locking = true; ret->fs_info = fs_info; return ret; } +static void btrfs_backref_iter_release(struct btrfs_backref_iter *iter) +{ + iter->bytenr = 0; + iter->item_ptr = 0; + iter->cur_ptr = 0; + iter->end_ptr = 0; + btrfs_release_path(iter->path); + memset(&iter->cur_key, 0, sizeof(iter->cur_key)); +} + int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr) { struct btrfs_fs_info *fs_info = iter->fs_info; @@ -2350,12 +2859,16 @@ int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr) ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0); if (ret < 0) return ret; - if (ret == 0) { + if (unlikely(ret == 0)) { + /* + * Key with offset -1 found, there would have to exist an extent + * item with such offset, but this is out of the valid range. + */ ret = -EUCLEAN; goto release; } - if (path->slots[0] == 0) { - WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG)); + if (unlikely(path->slots[0] == 0)) { + DEBUG_WARN(); ret = -EUCLEAN; goto release; } @@ -2421,6 +2934,14 @@ release: return ret; } +static bool btrfs_backref_iter_is_inline_ref(struct btrfs_backref_iter *iter) +{ + if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY || + iter->cur_key.type == BTRFS_METADATA_ITEM_KEY) + return true; + return false; +} + /* * Go to the next backref item of current bytenr, can be either inlined or * keyed. @@ -2433,7 +2954,7 @@ release: */ int btrfs_backref_iter_next(struct btrfs_backref_iter *iter) { - struct extent_buffer *eb = btrfs_backref_get_eb(iter); + struct extent_buffer *eb = iter->path->nodes[0]; struct btrfs_root *extent_root; struct btrfs_path *path = iter->path; struct btrfs_extent_inline_ref *iref; @@ -2484,16 +3005,13 @@ int btrfs_backref_iter_next(struct btrfs_backref_iter *iter) } void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info, - struct btrfs_backref_cache *cache, int is_reloc) + struct btrfs_backref_cache *cache, bool is_reloc) { int i; cache->rb_root = RB_ROOT; for (i = 0; i < BTRFS_MAX_LEVEL; i++) INIT_LIST_HEAD(&cache->pending[i]); - INIT_LIST_HEAD(&cache->changed); - INIT_LIST_HEAD(&cache->detached); - INIT_LIST_HEAD(&cache->leaves); INIT_LIST_HEAD(&cache->pending_edge); INIT_LIST_HEAD(&cache->useless_node); cache->fs_info = fs_info; @@ -2521,6 +3039,19 @@ struct btrfs_backref_node *btrfs_backref_alloc_node( return node; } +void btrfs_backref_free_node(struct btrfs_backref_cache *cache, + struct btrfs_backref_node *node) +{ + if (node) { + ASSERT(list_empty(&node->list)); + ASSERT(list_empty(&node->lower)); + ASSERT(node->eb == NULL); + cache->nr_nodes--; + btrfs_put_root(node->root); + kfree(node); + } +} + struct btrfs_backref_edge *btrfs_backref_alloc_edge( struct btrfs_backref_cache *cache) { @@ -2532,6 +3063,52 @@ struct btrfs_backref_edge *btrfs_backref_alloc_edge( return edge; } +void btrfs_backref_free_edge(struct btrfs_backref_cache *cache, + struct btrfs_backref_edge *edge) +{ + if (edge) { + cache->nr_edges--; + kfree(edge); + } +} + +void btrfs_backref_unlock_node_buffer(struct btrfs_backref_node *node) +{ + if (node->locked) { + btrfs_tree_unlock(node->eb); + node->locked = 0; + } +} + +void btrfs_backref_drop_node_buffer(struct btrfs_backref_node *node) +{ + if (node->eb) { + btrfs_backref_unlock_node_buffer(node); + free_extent_buffer(node->eb); + node->eb = NULL; + } +} + +/* + * Drop the backref node from cache without cleaning up its children + * edges. + * + * This can only be called on node without parent edges. + * The children edges are still kept as is. + */ +void btrfs_backref_drop_node(struct btrfs_backref_cache *tree, + struct btrfs_backref_node *node) +{ + ASSERT(list_empty(&node->upper)); + + btrfs_backref_drop_node_buffer(node); + list_del_init(&node->list); + list_del_init(&node->lower); + if (!RB_EMPTY_NODE(&node->rb_node)) + rb_erase(&node->rb_node, &tree->rb_root); + btrfs_backref_free_node(tree, node); +} + /* * Drop the backref node from cache, also cleaning up all its * upper edges and any uncached nodes in the path. @@ -2542,29 +3119,17 @@ struct btrfs_backref_edge *btrfs_backref_alloc_edge( void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache, struct btrfs_backref_node *node) { - struct btrfs_backref_node *upper; struct btrfs_backref_edge *edge; if (!node) return; - BUG_ON(!node->lowest && !node->detached); while (!list_empty(&node->upper)) { - edge = list_entry(node->upper.next, struct btrfs_backref_edge, - list[LOWER]); - upper = edge->node[UPPER]; + edge = list_first_entry(&node->upper, struct btrfs_backref_edge, + list[LOWER]); list_del(&edge->list[LOWER]); list_del(&edge->list[UPPER]); btrfs_backref_free_edge(cache, edge); - - /* - * Add the node to leaf node list if no other child block - * cached. - */ - if (list_empty(&upper->lower)) { - list_add_tail(&upper->lower, &cache->leaves); - upper->lowest = 1; - } } btrfs_backref_drop_node(cache, node); @@ -2576,33 +3141,26 @@ void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache, void btrfs_backref_release_cache(struct btrfs_backref_cache *cache) { struct btrfs_backref_node *node; - int i; - while (!list_empty(&cache->detached)) { - node = list_entry(cache->detached.next, - struct btrfs_backref_node, list); + while ((node = rb_entry_safe(rb_first(&cache->rb_root), + struct btrfs_backref_node, rb_node))) btrfs_backref_cleanup_node(cache, node); - } - - while (!list_empty(&cache->leaves)) { - node = list_entry(cache->leaves.next, - struct btrfs_backref_node, lower); - btrfs_backref_cleanup_node(cache, node); - } - - cache->last_trans = 0; - for (i = 0; i < BTRFS_MAX_LEVEL; i++) - ASSERT(list_empty(&cache->pending[i])); ASSERT(list_empty(&cache->pending_edge)); ASSERT(list_empty(&cache->useless_node)); - ASSERT(list_empty(&cache->changed)); - ASSERT(list_empty(&cache->detached)); - ASSERT(RB_EMPTY_ROOT(&cache->rb_root)); ASSERT(!cache->nr_nodes); ASSERT(!cache->nr_edges); } +static void btrfs_backref_link_edge(struct btrfs_backref_edge *edge, + struct btrfs_backref_node *lower, + struct btrfs_backref_node *upper) +{ + ASSERT(upper && lower && upper->level == lower->level + 1); + edge->node[LOWER] = lower; + edge->node[UPPER] = upper; + list_add_tail(&edge->list[LOWER], &lower->upper); +} /* * Handle direct tree backref * @@ -2671,7 +3229,7 @@ static int handle_direct_tree_backref(struct btrfs_backref_cache *cache, ASSERT(upper->checked); INIT_LIST_HEAD(&edge->list[UPPER]); } - btrfs_backref_link_edge(edge, cur, upper, LINK_LOWER); + btrfs_backref_link_edge(edge, cur, upper); return 0; } @@ -2682,12 +3240,14 @@ static int handle_direct_tree_backref(struct btrfs_backref_cache *cache, * We still need to do a tree search to find out the parents. This is for * TREE_BLOCK_REF backref (keyed or inlined). * + * @trans: Transaction handle. * @ref_key: The same as @ref_key in handle_direct_tree_backref() * @tree_key: The first key of this tree block. * @path: A clean (released) path, to avoid allocating path every time * the function get called. */ -static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, +static int handle_indirect_tree_backref(struct btrfs_trans_handle *trans, + struct btrfs_backref_cache *cache, struct btrfs_path *path, struct btrfs_key *ref_key, struct btrfs_key *tree_key, @@ -2707,8 +3267,12 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, root = btrfs_get_fs_root(fs_info, ref_key->offset, false); if (IS_ERR(root)) return PTR_ERR(root); - if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) - cur->cowonly = 1; + + /* We shouldn't be using backref cache for non-shareable roots. */ + if (unlikely(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))) { + btrfs_put_root(root); + return -EUCLEAN; + } if (btrfs_root_level(&root->root_item) == cur->level) { /* Tree root */ @@ -2735,8 +3299,8 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, level = cur->level + 1; /* Search the tree to find parent blocks referring to the block */ - path->search_commit_root = 1; - path->skip_locking = 1; + path->search_commit_root = true; + path->skip_locking = true; path->lowest_level = level; ret = btrfs_search_slot(NULL, root, tree_key, path, 0, 0); path->lowest_level = 0; @@ -2750,9 +3314,9 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, eb = path->nodes[level]; if (btrfs_node_blockptr(eb, path->slots[level]) != cur->bytenr) { btrfs_err(fs_info, -"couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)", - cur->bytenr, level - 1, root->root_key.objectid, - tree_key->objectid, tree_key->type, tree_key->offset); +"couldn't find block (%llu) (level %d) in tree (%llu) with key " BTRFS_KEY_FMT, + cur->bytenr, level - 1, btrfs_root_id(root), + BTRFS_KEY_FMT_VALUE(tree_key)); btrfs_put_root(root); ret = -ENOENT; goto out; @@ -2794,14 +3358,21 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, goto out; } upper->owner = btrfs_header_owner(eb); - if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) - upper->cowonly = 1; + + /* We shouldn't be using backref cache for non shareable roots. */ + if (unlikely(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))) { + btrfs_put_root(root); + btrfs_backref_free_edge(cache, edge); + btrfs_backref_free_node(cache, upper); + ret = -EUCLEAN; + goto out; + } /* * If we know the block isn't shared we can avoid * checking its backrefs. */ - if (btrfs_block_can_be_shared(root, eb)) + if (btrfs_block_can_be_shared(trans, root, eb)) upper->checked = 0; else upper->checked = 1; @@ -2828,7 +3399,7 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, if (!upper->owner) upper->owner = btrfs_header_owner(eb); } - btrfs_backref_link_edge(edge, lower, upper, LINK_LOWER); + btrfs_backref_link_edge(edge, lower, upper); if (rb_node) { btrfs_put_root(root); @@ -2849,17 +3420,18 @@ out: * links aren't yet bi-directional. Needs to finish such links. * Use btrfs_backref_finish_upper_links() to finish such linkage. * + * @trans: Transaction handle. * @path: Released path for indirect tree backref lookup * @iter: Released backref iter for extent tree search * @node_key: The first key of the tree block */ -int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache, +int btrfs_backref_add_tree_node(struct btrfs_trans_handle *trans, + struct btrfs_backref_cache *cache, struct btrfs_path *path, struct btrfs_backref_iter *iter, struct btrfs_key *node_key, struct btrfs_backref_node *cur) { - struct btrfs_fs_info *fs_info = cache->fs_info; struct btrfs_backref_edge *edge; struct btrfs_backref_node *exist; int ret; @@ -2876,7 +3448,7 @@ int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache, if (ret < 0) goto out; /* No extra backref? This means the tree block is corrupted */ - if (ret > 0) { + if (unlikely(ret > 0)) { ret = -EUCLEAN; goto out; } @@ -2888,8 +3460,8 @@ int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache, * type BTRFS_TREE_BLOCK_REF_KEY */ ASSERT(list_is_singular(&cur->upper)); - edge = list_entry(cur->upper.next, struct btrfs_backref_edge, - list[LOWER]); + edge = list_first_entry(&cur->upper, struct btrfs_backref_edge, + list[LOWER]); ASSERT(list_empty(&edge->list[UPPER])); exist = edge->node[UPPER]; /* @@ -2908,7 +3480,7 @@ int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache, int type; cond_resched(); - eb = btrfs_backref_get_eb(iter); + eb = iter->path->nodes[0]; key.objectid = iter->bytenr; if (btrfs_backref_iter_is_inline_ref(iter)) { @@ -2919,7 +3491,7 @@ int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache, ((unsigned long)iter->cur_ptr); type = btrfs_get_extent_inline_ref_type(eb, iref, BTRFS_REF_TYPE_BLOCK); - if (type == BTRFS_REF_TYPE_INVALID) { + if (unlikely(type == BTRFS_REF_TYPE_INVALID)) { ret = -EUCLEAN; goto out; } @@ -2948,25 +3520,21 @@ int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache, ret = handle_direct_tree_backref(cache, &key, cur); if (ret < 0) goto out; - continue; - } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) { - ret = -EINVAL; - btrfs_print_v0_err(fs_info); - btrfs_handle_fs_error(fs_info, ret, NULL); - goto out; - } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) { - continue; + } else if (key.type == BTRFS_TREE_BLOCK_REF_KEY) { + /* + * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref + * offset means the root objectid. We need to search + * the tree to get its parent bytenr. + */ + ret = handle_indirect_tree_backref(trans, cache, path, + &key, node_key, cur); + if (ret < 0) + goto out; } - /* - * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset - * means the root objectid. We need to search the tree to get - * its parent bytenr. + * Unrecognized tree backref items (if it can pass tree-checker) + * would be ignored. */ - ret = handle_indirect_tree_backref(cache, path, &key, node_key, - cur); - if (ret < 0) - goto out; } ret = 0; cur->checked = 1; @@ -2989,15 +3557,9 @@ int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache, ASSERT(start->checked); - /* Insert this node to cache if it's not COW-only */ - if (!start->cowonly) { - rb_node = rb_simple_insert(&cache->rb_root, start->bytenr, - &start->rb_node); - if (rb_node) - btrfs_backref_panic(cache->fs_info, start->bytenr, - -EEXIST); - list_add_tail(&start->lower, &cache->leaves); - } + rb_node = rb_simple_insert(&cache->rb_root, &start->simple_node); + if (rb_node) + btrfs_backref_panic(cache->fs_info, start->bytenr, -EEXIST); /* * Use breadth first search to iterate all related edges. @@ -3036,38 +3598,22 @@ int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache, * parents have already been linked. */ if (!RB_EMPTY_NODE(&upper->rb_node)) { - if (upper->lowest) { - list_del_init(&upper->lower); - upper->lowest = 0; - } - list_add_tail(&edge->list[UPPER], &upper->lower); continue; } /* Sanity check, we shouldn't have any unchecked nodes */ - if (!upper->checked) { - ASSERT(0); + if (unlikely(!upper->checked)) { + DEBUG_WARN("we should not have any unchecked nodes"); return -EUCLEAN; } - /* Sanity check, COW-only node has non-COW-only parent */ - if (start->cowonly != upper->cowonly) { - ASSERT(0); + rb_node = rb_simple_insert(&cache->rb_root, &upper->simple_node); + if (unlikely(rb_node)) { + btrfs_backref_panic(cache->fs_info, upper->bytenr, -EEXIST); return -EUCLEAN; } - /* Only cache non-COW-only (subvolume trees) tree blocks */ - if (!upper->cowonly) { - rb_node = rb_simple_insert(&cache->rb_root, upper->bytenr, - &upper->rb_node); - if (rb_node) { - btrfs_backref_panic(cache->fs_info, - upper->bytenr, -EEXIST); - return -EUCLEAN; - } - } - list_add_tail(&edge->list[UPPER], &upper->lower); /* |