From 1b60d2ec982a35c2953d81d035e1d7fc7c89f42a Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 23 Mar 2020 16:08:34 +0800 Subject: btrfs: backref: rename and move handle_one_tree_block() This function is the major part of backref cache build process, move it to backref.c so we can reuse it later. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/backref.c | 365 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 365 insertions(+) (limited to 'fs/btrfs/backref.c') diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 44808a0b480f..832071bbb8c9 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -13,6 +13,7 @@ #include "transaction.h" #include "delayed-ref.h" #include "locking.h" +#include "misc.h" /* Just an arbitrary number so we can be sure this happened */ #define BACKREF_FOUND_SHARED 6 @@ -2592,3 +2593,367 @@ void btrfs_backref_release_cache(struct btrfs_backref_cache *cache) ASSERT(!cache->nr_nodes); ASSERT(!cache->nr_edges); } + +/* + * Handle direct tree backref + * + * Direct tree backref means, the backref item shows its parent bytenr + * directly. This is for SHARED_BLOCK_REF backref (keyed or inlined). + * + * @ref_key: The converted backref key. + * For keyed backref, it's the item key. + * For inlined backref, objectid is the bytenr, + * type is btrfs_inline_ref_type, offset is + * btrfs_inline_ref_offset. + */ +static int handle_direct_tree_backref(struct btrfs_backref_cache *cache, + struct btrfs_key *ref_key, + struct btrfs_backref_node *cur) +{ + struct btrfs_backref_edge *edge; + struct btrfs_backref_node *upper; + struct rb_node *rb_node; + + ASSERT(ref_key->type == BTRFS_SHARED_BLOCK_REF_KEY); + + /* Only reloc root uses backref pointing to itself */ + if (ref_key->objectid == ref_key->offset) { + struct btrfs_root *root; + + cur->is_reloc_root = 1; + /* Only reloc backref cache cares about a specific root */ + if (cache->is_reloc) { + root = find_reloc_root(cache->fs_info, cur->bytenr); + if (WARN_ON(!root)) + return -ENOENT; + cur->root = root; + } else { + /* + * For generic purpose backref cache, reloc root node + * is useless. + */ + list_add(&cur->list, &cache->useless_node); + } + return 0; + } + + edge = btrfs_backref_alloc_edge(cache); + if (!edge) + return -ENOMEM; + + rb_node = rb_simple_search(&cache->rb_root, ref_key->offset); + if (!rb_node) { + /* Parent node not yet cached */ + upper = btrfs_backref_alloc_node(cache, ref_key->offset, + cur->level + 1); + if (!upper) { + btrfs_backref_free_edge(cache, edge); + return -ENOMEM; + } + + /* + * Backrefs for the upper level block isn't cached, add the + * block to pending list + */ + list_add_tail(&edge->list[UPPER], &cache->pending_edge); + } else { + /* Parent node already cached */ + upper = rb_entry(rb_node, struct btrfs_backref_node, rb_node); + ASSERT(upper->checked); + INIT_LIST_HEAD(&edge->list[UPPER]); + } + btrfs_backref_link_edge(edge, cur, upper, LINK_LOWER); + return 0; +} + +/* + * Handle indirect tree backref + * + * Indirect tree backref means, we only know which tree the node belongs to. + * We still need to do a tree search to find out the parents. This is for + * TREE_BLOCK_REF backref (keyed or inlined). + * + * @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 everytime + * the function get called. + */ +static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, + struct btrfs_path *path, + struct btrfs_key *ref_key, + struct btrfs_key *tree_key, + struct btrfs_backref_node *cur) +{ + struct btrfs_fs_info *fs_info = cache->fs_info; + struct btrfs_backref_node *upper; + struct btrfs_backref_node *lower; + struct btrfs_backref_edge *edge; + struct extent_buffer *eb; + struct btrfs_root *root; + struct btrfs_key root_key; + struct rb_node *rb_node; + int level; + bool need_check = true; + int ret; + + root_key.objectid = ref_key->offset; + root_key.type = BTRFS_ROOT_ITEM_KEY; + root_key.offset = (u64)-1; + root = btrfs_get_fs_root(fs_info, &root_key, false); + if (IS_ERR(root)) + return PTR_ERR(root); + if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) + cur->cowonly = 1; + + if (btrfs_root_level(&root->root_item) == cur->level) { + /* Tree root */ + ASSERT(btrfs_root_bytenr(&root->root_item) == cur->bytenr); + if (btrfs_should_ignore_reloc_root(root)) { + btrfs_put_root(root); + list_add(&cur->list, &cache->useless_node); + } else { + cur->root = root; + } + return 0; + } + + 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->lowest_level = level; + ret = btrfs_search_slot(NULL, root, tree_key, path, 0, 0); + path->lowest_level = 0; + if (ret < 0) { + btrfs_put_root(root); + return ret; + } + if (ret > 0 && path->slots[level] > 0) + path->slots[level]--; + + 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); + btrfs_put_root(root); + ret = -ENOENT; + goto out; + } + lower = cur; + + /* Add all nodes and edges in the path */ + for (; level < BTRFS_MAX_LEVEL; level++) { + if (!path->nodes[level]) { + ASSERT(btrfs_root_bytenr(&root->root_item) == + lower->bytenr); + if (btrfs_should_ignore_reloc_root(root)) { + btrfs_put_root(root); + list_add(&lower->list, &cache->useless_node); + } else { + lower->root = root; + } + break; + } + + edge = btrfs_backref_alloc_edge(cache); + if (!edge) { + btrfs_put_root(root); + ret = -ENOMEM; + goto out; + } + + eb = path->nodes[level]; + rb_node = rb_simple_search(&cache->rb_root, eb->start); + if (!rb_node) { + upper = btrfs_backref_alloc_node(cache, eb->start, + lower->level + 1); + if (!upper) { + btrfs_put_root(root); + btrfs_backref_free_edge(cache, edge); + ret = -ENOMEM; + goto out; + } + upper->owner = btrfs_header_owner(eb); + if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) + upper->cowonly = 1; + + /* + * If we know the block isn't shared we can avoid + * checking its backrefs. + */ + if (btrfs_block_can_be_shared(root, eb)) + upper->checked = 0; + else + upper->checked = 1; + + /* + * Add the block to pending list if we need to check its + * backrefs, we only do this once while walking up a + * tree as we will catch anything else later on. + */ + if (!upper->checked && need_check) { + need_check = false; + list_add_tail(&edge->list[UPPER], + &cache->pending_edge); + } else { + if (upper->checked) + need_check = true; + INIT_LIST_HEAD(&edge->list[UPPER]); + } + } else { + upper = rb_entry(rb_node, struct btrfs_backref_node, + rb_node); + ASSERT(upper->checked); + INIT_LIST_HEAD(&edge->list[UPPER]); + if (!upper->owner) + upper->owner = btrfs_header_owner(eb); + } + btrfs_backref_link_edge(edge, lower, upper, LINK_LOWER); + + if (rb_node) { + btrfs_put_root(root); + break; + } + lower = upper; + upper = NULL; + } +out: + btrfs_release_path(path); + return ret; +} + +/* + * Add backref node @cur into @cache. + * + * NOTE: Even if the function returned 0, @cur is not yet cached as its upper + * links aren't yet bi-directional. Needs to finish such links. + * + * @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, + 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; + + ret = btrfs_backref_iter_start(iter, cur->bytenr); + if (ret < 0) + return ret; + /* + * We skip the first btrfs_tree_block_info, as we don't use the key + * stored in it, but fetch it from the tree block + */ + if (btrfs_backref_has_tree_block_info(iter)) { + ret = btrfs_backref_iter_next(iter); + if (ret < 0) + goto out; + /* No extra backref? This means the tree block is corrupted */ + if (ret > 0) { + ret = -EUCLEAN; + goto out; + } + } + WARN_ON(cur->checked); + if (!list_empty(&cur->upper)) { + /* + * The backref was added previously when processing backref of + * type BTRFS_TREE_BLOCK_REF_KEY + */ + ASSERT(list_is_singular(&cur->upper)); + edge = list_entry(cur->upper.next, struct btrfs_backref_edge, + list[LOWER]); + ASSERT(list_empty(&edge->list[UPPER])); + exist = edge->node[UPPER]; + /* + * Add the upper level block to pending list if we need check + * its backrefs + */ + if (!exist->checked) + list_add_tail(&edge->list[UPPER], &cache->pending_edge); + } else { + exist = NULL; + } + + for (; ret == 0; ret = btrfs_backref_iter_next(iter)) { + struct extent_buffer *eb; + struct btrfs_key key; + int type; + + cond_resched(); + eb = btrfs_backref_get_eb(iter); + + key.objectid = iter->bytenr; + if (btrfs_backref_iter_is_inline_ref(iter)) { + struct btrfs_extent_inline_ref *iref; + + /* Update key for inline backref */ + iref = (struct btrfs_extent_inline_ref *) + ((unsigned long)iter->cur_ptr); + type = btrfs_get_extent_inline_ref_type(eb, iref, + BTRFS_REF_TYPE_BLOCK); + if (type == BTRFS_REF_TYPE_INVALID) { + ret = -EUCLEAN; + goto out; + } + key.type = type; + key.offset = btrfs_extent_inline_ref_offset(eb, iref); + } else { + key.type = iter->cur_key.type; + key.offset = iter->cur_key.offset; + } + + /* + * Parent node found and matches current inline ref, no need to + * rebuild this node for this inline ref + */ + if (exist && + ((key.type == BTRFS_TREE_BLOCK_REF_KEY && + exist->owner == key.offset) || + (key.type == BTRFS_SHARED_BLOCK_REF_KEY && + exist->bytenr == key.offset))) { + exist = NULL; + continue; + } + + /* SHARED_BLOCK_REF means key.offset is the parent bytenr */ + if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) { + 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; + } + + /* + * 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(cache, path, &key, node_key, + cur); + if (ret < 0) + goto out; + } + ret = 0; + cur->checked = 1; + WARN_ON(exist); +out: + btrfs_backref_iter_release(iter); + return ret; +} -- cgit v1.2.3