diff options
Diffstat (limited to 'fs/btrfs/extent-tree.c')
| -rw-r--r-- | fs/btrfs/extent-tree.c | 685 |
1 files changed, 423 insertions, 262 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 3774c191e36d..d77498e7671c 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -104,10 +104,7 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, struct btrfs_delayed_ref_head *head; struct btrfs_delayed_ref_root *delayed_refs; struct btrfs_path *path; - struct btrfs_extent_item *ei; - struct extent_buffer *leaf; struct btrfs_key key; - u32 item_size; u64 num_refs; u64 extent_flags; u64 owner = 0; @@ -126,11 +123,6 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, if (!path) return -ENOMEM; - if (!trans) { - path->skip_locking = 1; - path->search_commit_root = 1; - } - search_again: key.objectid = bytenr; key.offset = offset; @@ -144,7 +136,7 @@ search_again: if (ret < 0) goto out_free; - if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) { + if (ret > 0 && key.type == BTRFS_METADATA_ITEM_KEY) { if (path->slots[0]) { path->slots[0]--; btrfs_item_key_to_cpu(path->nodes[0], &key, @@ -157,38 +149,37 @@ search_again: } if (ret == 0) { - leaf = path->nodes[0]; - item_size = btrfs_item_size(leaf, path->slots[0]); - if (item_size >= sizeof(*ei)) { - ei = btrfs_item_ptr(leaf, path->slots[0], - struct btrfs_extent_item); - num_refs = btrfs_extent_refs(leaf, ei); - extent_flags = btrfs_extent_flags(leaf, ei); - owner = btrfs_get_extent_owner_root(fs_info, leaf, - path->slots[0]); - } else { + struct extent_buffer *leaf = path->nodes[0]; + struct btrfs_extent_item *ei; + const u32 item_size = btrfs_item_size(leaf, path->slots[0]); + + if (unlikely(item_size < sizeof(*ei))) { ret = -EUCLEAN; btrfs_err(fs_info, "unexpected extent item size, has %u expect >= %zu", item_size, sizeof(*ei)); - if (trans) - btrfs_abort_transaction(trans, ret); - else - btrfs_handle_fs_error(fs_info, ret, NULL); - + btrfs_abort_transaction(trans, ret); goto out_free; } - BUG_ON(num_refs == 0); + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); + num_refs = btrfs_extent_refs(leaf, ei); + if (unlikely(num_refs == 0)) { + ret = -EUCLEAN; + btrfs_err(fs_info, + "unexpected zero reference count for extent item (%llu %u %llu)", + key.objectid, key.type, key.offset); + btrfs_abort_transaction(trans, ret); + goto out_free; + } + extent_flags = btrfs_extent_flags(leaf, ei); + owner = btrfs_get_extent_owner_root(fs_info, leaf, path->slots[0]); } else { num_refs = 0; extent_flags = 0; ret = 0; } - if (!trans) - goto out; - delayed_refs = &trans->transaction->delayed_refs; spin_lock(&delayed_refs->lock); head = btrfs_find_delayed_ref_head(delayed_refs, bytenr); @@ -211,15 +202,13 @@ search_again: spin_lock(&head->lock); if (head->extent_op && head->extent_op->update_flags) extent_flags |= head->extent_op->flags_to_set; - else - BUG_ON(num_refs == 0); num_refs += head->ref_mod; spin_unlock(&head->lock); mutex_unlock(&head->mutex); } spin_unlock(&delayed_refs->lock); -out: + WARN_ON(num_refs == 0); if (refs) *refs = num_refs; @@ -1632,7 +1621,7 @@ static int run_delayed_extent_op(struct btrfs_trans_handle *trans, if (metadata) { key.type = BTRFS_METADATA_ITEM_KEY; - key.offset = extent_op->level; + key.offset = head->level; } else { key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = head->num_bytes; @@ -1667,7 +1656,7 @@ again: ret = -EUCLEAN; btrfs_err(fs_info, "missing extent item for extent %llu num_bytes %llu level %d", - head->bytenr, head->num_bytes, extent_op->level); + head->bytenr, head->num_bytes, head->level); goto out; } } @@ -1726,7 +1715,6 @@ static int run_delayed_tree_ref(struct btrfs_trans_handle *trans, .generation = trans->transid, }; - BUG_ON(!extent_op || !extent_op->update_flags); ret = alloc_reserved_tree_block(trans, node, extent_op); if (!ret) btrfs_record_squota_delta(fs_info, &delta); @@ -2233,7 +2221,6 @@ int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans, struct extent_buffer *eb, u64 flags) { struct btrfs_delayed_extent_op *extent_op; - int level = btrfs_header_level(eb); int ret; extent_op = btrfs_alloc_delayed_extent_op(); @@ -2243,9 +2230,9 @@ int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans, extent_op->flags_to_set = flags; extent_op->update_flags = true; extent_op->update_key = false; - extent_op->level = level; - ret = btrfs_add_delayed_extent_op(trans, eb->start, eb->len, extent_op); + ret = btrfs_add_delayed_extent_op(trans, eb->start, eb->len, + btrfs_header_level(eb), extent_op); if (ret) btrfs_free_delayed_extent_op(extent_op); return ret; @@ -3419,10 +3406,10 @@ out_delayed_unlock: return 0; } -void btrfs_free_tree_block(struct btrfs_trans_handle *trans, - u64 root_id, - struct extent_buffer *buf, - u64 parent, int last_ref) +int btrfs_free_tree_block(struct btrfs_trans_handle *trans, + u64 root_id, + struct extent_buffer *buf, + u64 parent, int last_ref) { struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_block_group *bg; @@ -3449,11 +3436,12 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans, btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf), 0, false); btrfs_ref_tree_mod(fs_info, &generic_ref); ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL); - BUG_ON(ret); /* -ENOMEM */ + if (ret < 0) + return ret; } if (!last_ref) - return; + return 0; if (btrfs_header_generation(buf) != trans->transid) goto out; @@ -3510,6 +3498,7 @@ out: * matter anymore. */ clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags); + return 0; } /* Can return -ENOMEM */ @@ -4864,7 +4853,7 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans, struct btrfs_path *path; struct extent_buffer *leaf; u32 size = sizeof(*extent_item) + sizeof(*iref); - u64 flags = extent_op->flags_to_set; + const u64 flags = (extent_op ? extent_op->flags_to_set : 0); /* The owner of a tree block is the level. */ int level = btrfs_delayed_ref_owner(node); bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA); @@ -5121,7 +5110,6 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, struct btrfs_key ins; struct btrfs_block_rsv *block_rsv; struct extent_buffer *buf; - struct btrfs_delayed_extent_op *extent_op; u64 flags = 0; int ret; u32 blocksize = fs_info->nodesize; @@ -5164,6 +5152,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, BUG_ON(parent > 0); if (root_objectid != BTRFS_TREE_LOG_OBJECTID) { + struct btrfs_delayed_extent_op *extent_op; struct btrfs_ref generic_ref = { .action = BTRFS_ADD_DELAYED_EXTENT, .bytenr = ins.objectid, @@ -5172,30 +5161,34 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, .owning_root = owning_root, .ref_root = root_objectid, }; - extent_op = btrfs_alloc_delayed_extent_op(); - if (!extent_op) { - ret = -ENOMEM; - goto out_free_buf; + + if (!skinny_metadata || flags != 0) { + extent_op = btrfs_alloc_delayed_extent_op(); + if (!extent_op) { + ret = -ENOMEM; + goto out_free_buf; + } + if (key) + memcpy(&extent_op->key, key, sizeof(extent_op->key)); + else + memset(&extent_op->key, 0, sizeof(extent_op->key)); + extent_op->flags_to_set = flags; + extent_op->update_key = (skinny_metadata ? false : true); + extent_op->update_flags = (flags != 0); + } else { + extent_op = NULL; } - if (key) - memcpy(&extent_op->key, key, sizeof(extent_op->key)); - else - memset(&extent_op->key, 0, sizeof(extent_op->key)); - extent_op->flags_to_set = flags; - extent_op->update_key = skinny_metadata ? false : true; - extent_op->update_flags = true; - extent_op->level = level; btrfs_init_tree_ref(&generic_ref, level, btrfs_root_id(root), false); btrfs_ref_tree_mod(fs_info, &generic_ref); ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, extent_op); - if (ret) - goto out_free_delayed; + if (ret) { + btrfs_free_delayed_extent_op(extent_op); + goto out_free_buf; + } } return buf; -out_free_delayed: - btrfs_free_delayed_extent_op(extent_op); out_free_buf: btrfs_tree_unlock(buf); free_extent_buffer(buf); @@ -5220,11 +5213,99 @@ struct walk_control { int reada_slot; int reada_count; int restarted; + /* Indicate that extent info needs to be looked up when walking the tree. */ + int lookup_info; }; +/* + * This is our normal stage. We are traversing blocks the current snapshot owns + * and we are dropping any of our references to any children we are able to, and + * then freeing the block once we've processed all of the children. + */ #define DROP_REFERENCE 1 + +/* + * We enter this stage when we have to walk into a child block (meaning we can't + * simply drop our reference to it from our current parent node) and there are + * more than one reference on it. If we are the owner of any of the children + * blocks from the current parent node then we have to do the FULL_BACKREF dance + * on them in order to drop our normal ref and add the shared ref. + */ #define UPDATE_BACKREF 2 +/* + * Decide if we need to walk down into this node to adjust the references. + * + * @root: the root we are currently deleting + * @wc: the walk control for this deletion + * @eb: the parent eb that we're currently visiting + * @refs: the number of refs for wc->level - 1 + * @flags: the flags for wc->level - 1 + * @slot: the slot in the eb that we're currently checking + * + * This is meant to be called when we're evaluating if a node we point to at + * wc->level should be read and walked into, or if we can simply delete our + * reference to it. We return true if we should walk into the node, false if we + * can skip it. + * + * We have assertions in here to make sure this is called correctly. We assume + * that sanity checking on the blocks read to this point has been done, so any + * corrupted file systems must have been caught before calling this function. + */ +static bool visit_node_for_delete(struct btrfs_root *root, struct walk_control *wc, + struct extent_buffer *eb, u64 refs, u64 flags, int slot) +{ + struct btrfs_key key; + u64 generation; + int level = wc->level; + + ASSERT(level > 0); + ASSERT(wc->refs[level - 1] > 0); + + /* + * The update backref stage we only want to skip if we already have + * FULL_BACKREF set, otherwise we need to read. + */ + if (wc->stage == UPDATE_BACKREF) { + if (level == 1 && flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) + return false; + return true; + } + + /* + * We're the last ref on this block, we must walk into it and process + * any refs it's pointing at. + */ + if (wc->refs[level - 1] == 1) + return true; + + /* + * If we're already FULL_BACKREF then we know we can just drop our + * current reference. + */ + if (level == 1 && flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) + return false; + + /* + * This block is older than our creation generation, we can drop our + * reference to it. + */ + generation = btrfs_node_ptr_generation(eb, slot); + if (!wc->update_ref || generation <= root->root_key.offset) + return false; + + /* + * This block was processed from a previous snapshot deletion run, we + * can skip it. + */ + btrfs_node_key_to_cpu(eb, &key, slot); + if (btrfs_comp_cpu_keys(&key, &wc->update_progress) < 0) + return false; + + /* All other cases we need to wander into the node. */ + return true; +} + static noinline void reada_walk_down(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct walk_control *wc, @@ -5236,7 +5317,6 @@ static noinline void reada_walk_down(struct btrfs_trans_handle *trans, u64 refs; u64 flags; u32 nritems; - struct btrfs_key key; struct extent_buffer *eb; int ret; int slot; @@ -5276,28 +5356,19 @@ static noinline void reada_walk_down(struct btrfs_trans_handle *trans, /* We don't care about errors in readahead. */ if (ret < 0) continue; - BUG_ON(refs == 0); - if (wc->stage == DROP_REFERENCE) { - if (refs == 1) - goto reada; + /* + * This could be racey, it's conceivable that we raced and end + * up with a bogus refs count, if that's the case just skip, if + * we are actually corrupt we will notice when we look up + * everything again with our locks. + */ + if (refs == 0) + continue; - if (wc->level == 1 && - (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) - continue; - if (!wc->update_ref || - generation <= root->root_key.offset) - continue; - btrfs_node_key_to_cpu(eb, &key, slot); - ret = btrfs_comp_cpu_keys(&key, - &wc->update_progress); - if (ret < 0) - continue; - } else { - if (wc->level == 1 && - (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) - continue; - } + /* If we don't need to visit this node don't reada. */ + if (!visit_node_for_delete(root, wc, eb, refs, flags, slot)) + continue; reada: btrfs_readahead_node_child(eb, slot); nread++; @@ -5316,7 +5387,7 @@ reada: static noinline int walk_down_proc(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, - struct walk_control *wc, int lookup_info) + struct walk_control *wc) { struct btrfs_fs_info *fs_info = root->fs_info; int level = wc->level; @@ -5331,19 +5402,22 @@ static noinline int walk_down_proc(struct btrfs_trans_handle *trans, * when reference count of tree block is 1, it won't increase * again. once full backref flag is set, we never clear it. */ - if (lookup_info && + if (wc->lookup_info && ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) || (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) { - BUG_ON(!path->locks[level]); + ASSERT(path->locks[level]); ret = btrfs_lookup_extent_info(trans, fs_info, eb->start, level, 1, &wc->refs[level], &wc->flags[level], NULL); - BUG_ON(ret == -ENOMEM); if (ret) return ret; - BUG_ON(wc->refs[level] == 0); + if (unlikely(wc->refs[level] == 0)) { + btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0", + eb->start); + return -EUCLEAN; + } } if (wc->stage == DROP_REFERENCE) { @@ -5359,13 +5433,22 @@ static noinline int walk_down_proc(struct btrfs_trans_handle *trans, /* wc->stage == UPDATE_BACKREF */ if (!(wc->flags[level] & flag)) { - BUG_ON(!path->locks[level]); + ASSERT(path->locks[level]); ret = btrfs_inc_ref(trans, root, eb, 1); - BUG_ON(ret); /* -ENOMEM */ + if (ret) { + btrfs_abort_transaction(trans, ret); + return ret; + } ret = btrfs_dec_ref(trans, root, eb, 0); - BUG_ON(ret); /* -ENOMEM */ + if (ret) { + btrfs_abort_transaction(trans, ret); + return ret; + } ret = btrfs_set_disk_extent_flags(trans, eb, flag); - BUG_ON(ret); /* -ENOMEM */ + if (ret) { + btrfs_abort_transaction(trans, ret); + return ret; + } wc->flags[level] |= flag; } @@ -5408,6 +5491,132 @@ static int check_ref_exists(struct btrfs_trans_handle *trans, } /* + * We may not have an uptodate block, so if we are going to walk down into this + * block we need to drop the lock, read it off of the disk, re-lock it and + * return to continue dropping the snapshot. + */ +static int check_next_block_uptodate(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct walk_control *wc, + struct extent_buffer *next) +{ + struct btrfs_tree_parent_check check = { 0 }; + u64 generation; + int level = wc->level; + int ret; + + btrfs_assert_tree_write_locked(next); + + generation = btrfs_node_ptr_generation(path->nodes[level], path->slots[level]); + + if (btrfs_buffer_uptodate(next, generation, 0)) + return 0; + + check.level = level - 1; + check.transid = generation; + check.owner_root = btrfs_root_id(root); + check.has_first_key = true; + btrfs_node_key_to_cpu(path->nodes[level], &check.first_key, path->slots[level]); + + btrfs_tree_unlock(next); + if (level == 1) + reada_walk_down(trans, root, wc, path); + ret = btrfs_read_extent_buffer(next, &check); + if (ret) { + free_extent_buffer(next); + return ret; + } + btrfs_tree_lock(next); + wc->lookup_info = 1; + return 0; +} + +/* + * If we determine that we don't have to visit wc->level - 1 then we need to + * determine if we can drop our reference. + * + * If we are UPDATE_BACKREF then we will not, we need to update our backrefs. + * + * If we are DROP_REFERENCE this will figure out if we need to drop our current + * reference, skipping it if we dropped it from a previous incompleted drop, or + * dropping it if we still have a reference to it. + */ +static int maybe_drop_reference(struct btrfs_trans_handle *trans, struct btrfs_root *root, + struct btrfs_path *path, struct walk_control *wc, + struct extent_buffer *next, u64 owner_root) +{ + struct btrfs_ref ref = { + .action = BTRFS_DROP_DELAYED_REF, + .bytenr = next->start, + .num_bytes = root->fs_info->nodesize, + .owning_root = owner_root, + .ref_root = btrfs_root_id(root), + }; + int level = wc->level; + int ret; + + /* We are UPDATE_BACKREF, we're not dropping anything. */ + if (wc->stage == UPDATE_BACKREF) + return 0; + + if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) { + ref.parent = path->nodes[level]->start; + } else { + ASSERT(btrfs_root_id(root) == btrfs_header_owner(path->nodes[level])); + if (btrfs_root_id(root) != btrfs_header_owner(path->nodes[level])) { + btrfs_err(root->fs_info, "mismatched block owner"); + return -EIO; + } + } + + /* + * If we had a drop_progress we need to verify the refs are set as + * expected. If we find our ref then we know that from here on out + * everything should be correct, and we can clear the + * ->restarted flag. + */ + if (wc->restarted) { + ret = check_ref_exists(trans, root, next->start, ref.parent, + level - 1); + if (ret <= 0) + return ret; + ret = 0; + wc->restarted = 0; + } + + /* + * Reloc tree doesn't contribute to qgroup numbers, and we have already + * accounted them at merge time (replace_path), thus we could skip + * expensive subtree trace here. + */ + if (btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID && + wc->refs[level - 1] > 1) { + u64 generation = btrfs_node_ptr_generation(path->nodes[level], + path->slots[level]); + + ret = btrfs_qgroup_trace_subtree(trans, next, generation, level - 1); + if (ret) { + btrfs_err_rl(root->fs_info, +"error %d accounting shared subtree, quota is out of sync, rescan required", + ret); + } + } + + /* + * We need to update the next key in our walk control so we can update + * the drop_progress key accordingly. We don't care if find_next_key + * doesn't find a key because that means we're at the end and are going + * to clean up now. + */ + wc->drop_level = level; + find_next_key(path, level, &wc->drop_progress); + + btrfs_init_tree_ref(&ref, level - 1, 0, false); + return btrfs_free_extent(trans, &ref); +} + +/* * helper to process tree block pointer. * * when wc->stage == DROP_REFERENCE, this function checks @@ -5423,19 +5632,15 @@ static int check_ref_exists(struct btrfs_trans_handle *trans, static noinline int do_walk_down(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, - struct walk_control *wc, int *lookup_info) + struct walk_control *wc) { struct btrfs_fs_info *fs_info = root->fs_info; u64 bytenr; u64 generation; u64 owner_root = 0; - struct btrfs_tree_parent_check check = { 0 }; - struct btrfs_key key; struct extent_buffer *next; int level = wc->level; - int reada = 0; int ret = 0; - bool need_account = false; generation = btrfs_node_ptr_generation(path->nodes[level], path->slots[level]); @@ -5446,27 +5651,17 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans, */ if (wc->stage == UPDATE_BACKREF && generation <= root->root_key.offset) { - *lookup_info = 1; + wc->lookup_info = 1; return 1; } bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]); - check.level = level - 1; - check.transid = generation; - check.owner_root = btrfs_root_id(root); - check.has_first_key = true; - btrfs_node_key_to_cpu(path->nodes[level], &check.first_key, - path->slots[level]); + next = btrfs_find_create_tree_block(fs_info, bytenr, btrfs_root_id(root), + level - 1); + if (IS_ERR(next)) + return PTR_ERR(next); - next = find_extent_buffer(fs_info, bytenr); - if (!next) { - next = btrfs_find_create_tree_block(fs_info, bytenr, - btrfs_root_id(root), level - 1); - if (IS_ERR(next)) - return PTR_ERR(next); - reada = 1; - } btrfs_tree_lock(next); ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1, @@ -5477,57 +5672,32 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans, goto out_unlock; if (unlikely(wc->refs[level - 1] == 0)) { - btrfs_err(fs_info, "Missing references."); - ret = -EIO; + btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0", + bytenr); + ret = -EUCLEAN; goto out_unlock; } - *lookup_info = 0; + wc->lookup_info = 0; - if (wc->stage == DROP_REFERENCE) { - if (wc->refs[level - 1] > 1) { - need_account = true; - if (level == 1 && - (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF)) - goto skip; - - if (!wc->update_ref || - generation <= root->root_key.offset) - goto skip; - - btrfs_node_key_to_cpu(path->nodes[level], &key, - path->slots[level]); - ret = btrfs_comp_cpu_keys(&key, &wc->update_progress); - if (ret < 0) - goto skip; + /* If we don't have to walk into this node skip it. */ + if (!visit_node_for_delete(root, wc, path->nodes[level], + wc->refs[level - 1], wc->flags[level - 1], + path->slots[level])) + goto skip; - wc->stage = UPDATE_BACKREF; - wc->shared_level = level - 1; - } - } else { - if (level == 1 && - (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF)) - goto skip; + /* + * We have to walk down into this node, and if we're currently at the + * DROP_REFERNCE stage and this block is shared then we need to switch + * to the UPDATE_BACKREF stage in order to convert to FULL_BACKREF. + */ + if (wc->stage == DROP_REFERENCE && wc->refs[level - 1] > 1) { + wc->stage = UPDATE_BACKREF; + wc->shared_level = level - 1; } - if (!btrfs_buffer_uptodate(next, generation, 0)) { - btrfs_tree_unlock(next); - free_extent_buffer(next); - next = NULL; - *lookup_info = 1; - } - - if (!next) { - if (reada && level == 1) - reada_walk_down(trans, root, wc, path); - next = read_tree_block(fs_info, bytenr, &check); - if (IS_ERR(next)) { - return PTR_ERR(next); - } else if (!extent_buffer_uptodate(next)) { - free_extent_buffer(next); - return -EIO; - } - btrfs_tree_lock(next); - } + ret = check_next_block_uptodate(trans, root, path, wc, next); + if (ret) + return ret; level--; ASSERT(level == btrfs_header_level(next)); @@ -5544,78 +5714,12 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans, wc->reada_slot = 0; return 0; skip: + ret = maybe_drop_reference(trans, root, path, wc, next, owner_root); + if (ret) + goto out_unlock; wc->refs[level - 1] = 0; wc->flags[level - 1] = 0; - if (wc->stage == DROP_REFERENCE) { - struct btrfs_ref ref = { - .action = BTRFS_DROP_DELAYED_REF, - .bytenr = bytenr, - .num_bytes = fs_info->nodesize, - .owning_root = owner_root, - .ref_root = btrfs_root_id(root), - }; - if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) { - ref.parent = path->nodes[level]->start; - } else { - ASSERT(btrfs_root_id(root) == - btrfs_header_owner(path->nodes[level])); - if (btrfs_root_id(root) != - btrfs_header_owner(path->nodes[level])) { - btrfs_err(root->fs_info, - "mismatched block owner"); - ret = -EIO; - goto out_unlock; - } - } - - /* - * If we had a drop_progress we need to verify the refs are set - * as expected. If we find our ref then we know that from here - * on out everything should be correct, and we can clear the - * ->restarted flag. - */ - if (wc->restarted) { - ret = check_ref_exists(trans, root, bytenr, ref.parent, - level - 1); - if (ret < 0) - goto out_unlock; - if (ret == 0) - goto no_delete; - ret = 0; - wc->restarted = 0; - } - - /* - * Reloc tree doesn't contribute to qgroup numbers, and we have - * already accounted them at merge time (replace_path), - * thus we could skip expensive subtree trace here. - */ - if (btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID && need_account) { - ret = btrfs_qgroup_trace_subtree(trans, next, - generation, level - 1); - if (ret) { - btrfs_err_rl(fs_info, - "Error %d accounting shared subtree. Quota is out of sync, rescan required.", - ret); - } - } - - /* - * We need to update the next key in our walk control so we can - * update the drop_progress key accordingly. We don't care if - * find_next_key doesn't find a key because that means we're at - * the end and are going to clean up now. - */ - wc->drop_level = level; - find_next_key(path, level, &wc->drop_progress); - - btrfs_init_tree_ref(&ref, level - 1, 0, false); - ret = btrfs_free_extent(trans, &ref); - if (ret) - goto out_unlock; - } -no_delete: - *lookup_info = 1; + wc->lookup_info = 1; ret = 1; out_unlock: @@ -5643,13 +5747,13 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans, struct walk_control *wc) { struct btrfs_fs_info *fs_info = root->fs_info; - int ret; + int ret = 0; int level = wc->level; struct extent_buffer *eb = path->nodes[level]; u64 parent = 0; if (wc->stage == UPDATE_BACKREF) { - BUG_ON(wc->shared_level < level); + ASSERT(wc->shared_level >= level); if (level < wc->shared_level) goto out; @@ -5667,7 +5771,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans, * count is one. */ if (!path->locks[level]) { - BUG_ON(level == 0); + ASSERT(level > 0); btrfs_tree_lock(eb); path->locks[level] = BTRFS_WRITE_LOCK; @@ -5681,7 +5785,12 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans, path->locks[level] = 0; return ret; } - BUG_ON(wc->refs[level] == 0); + if (unlikely(wc->refs[level] == 0)) { + btrfs_tree_unlock_rw(eb, path->locks[level]); + btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0", + eb->start); + return -EUCLEAN; + } if (wc->refs[level] == 1) { btrfs_tree_unlock_rw(eb, path->locks[level]); path->locks[level] = 0; @@ -5691,7 +5800,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans, } /* wc->stage == DROP_REFERENCE */ - BUG_ON(wc->refs[level] > 1 && !path->locks[level]); + ASSERT(path->locks[level] || wc->refs[level] == 1); if (wc->refs[level] == 1) { if (level == 0) { @@ -5699,7 +5808,10 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans, ret = btrfs_dec_ref(trans, root, eb, 1); else ret = btrfs_dec_ref(trans, root, eb, 0); - BUG_ON(ret); /* -ENOMEM */ + if (ret) { + btrfs_abort_transaction(trans, ret); + return ret; + } if (is_fstree(btrfs_root_id(root))) { ret = btrfs_qgroup_trace_leaf_items(trans, eb); if (ret) { @@ -5730,12 +5842,14 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans, goto owner_mismatch; } - btrfs_free_tree_block(trans, btrfs_root_id(root), eb, parent, - wc->refs[level] == 1); + ret = btrfs_free_tree_block(trans, btrfs_root_id(root), eb, parent, + wc->refs[level] == 1); + if (ret < 0) + btrfs_abort_transaction(trans, ret); out: wc->refs[level] = 0; wc->flags[level] = 0; - return 0; + return ret; owner_mismatch: btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu", @@ -5743,17 +5857,38 @@ owner_mismatch: return -EUCLEAN; } +/* + * walk_down_tree consists of two steps. + * + * walk_down_proc(). Look up the reference count and reference of our current + * wc->level. At this point path->nodes[wc->level] should be populated and + * uptodate, and in most cases should already be locked. If we are in + * DROP_REFERENCE and our refcount is > 1 then we've entered a shared node and + * we can walk back up the tree. If we are UPDATE_BACKREF we have to set + * FULL_BACKREF on this node if it's not already set, and then do the + * FULL_BACKREF conversion dance, which is to drop the root reference and add + * the shared reference to all of this nodes children. + * + * do_walk_down(). This is where we actually start iterating on the children of + * our current path->nodes[wc->level]. For DROP_REFERENCE that means dropping + * our reference to the children that return false from visit_node_for_delete(), + * which has various conditions where we know we can just drop our reference + * without visiting the node. For UPDATE_BACKREF we will skip any children that + * visit_node_for_delete() returns false for, only walking down when necessary. + * The bulk of the work for UPDATE_BACKREF occurs in the walk_up_tree() part of + * snapshot deletion. + */ static noinline int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct walk_control *wc) { int level = wc->level; - int lookup_info = 1; int ret = 0; + wc->lookup_info = 1; while (level >= 0) { - ret = walk_down_proc(trans, root, path, wc, lookup_info); + ret = walk_down_proc(trans, root, path, wc); if (ret) break; @@ -5764,7 +5899,7 @@ static noinline int walk_down_tree(struct btrfs_trans_handle *trans, btrfs_header_nritems(path->nodes[level])) break; - ret = do_walk_down(trans, root, path, wc, &lookup_info); + ret = do_walk_down(trans, root, path, wc); if (ret > 0) { path->slots[level]++; continue; @@ -5775,6 +5910,23 @@ static noinline int walk_down_tree(struct btrfs_trans_handle *trans, return (ret == 1) ? 0 : ret; } +/* + * walk_up_tree() is responsible for making sure we visit every slot on our + * current node, and if we're at the end of that node then we call + * walk_up_proc() on our current node which will do one of a few things based on + * our stage. + * + * UPDATE_BACKREF. If we wc->level is currently less than our wc->shared_level + * then we need to walk back up the tree, and then going back down into the + * other slots via walk_down_tree to update any other children from our original + * wc->shared_level. Once we're at or above our wc->shared_level we can switch + * back to DROP_REFERENCE, lookup the current nodes refs and flags, and carry on. + * + * DROP_REFERENCE. If our refs == 1 then we're going to free this tree block. + * If we're level 0 then we need to btrfs_dec_ref() on all of the data extents + * in our current leaf. After that we call btrfs_free_tree_block() on the + * current node and walk up to the next node to walk down the next slot. + */ static noinline int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, @@ -5833,8 +5985,8 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) struct btrfs_root_item *root_item = &root->root_item; struct walk_control *wc; struct btrfs_key key; - int err = 0; - int ret; + const u64 rootid = btrfs_root_id(root); + int ret = 0; int level; bool root_dropped = false; bool unfinished_drop = false; @@ -5843,14 +5995,14 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) path = btrfs_alloc_path(); if (!path) { - err = -ENOMEM; + ret = -ENOMEM; goto out; } wc = kzalloc(sizeof(*wc), GFP_NOFS); if (!wc) { btrfs_free_path(path); - err = -ENOMEM; + ret = -ENOMEM; goto out; } @@ -5863,12 +6015,12 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) else trans = btrfs_start_transaction(tree_root, 0); if (IS_ERR(trans)) { - err = PTR_ERR(trans); + ret = PTR_ERR(trans); goto out_free; } - err = btrfs_run_delayed_items(trans); - if (err) + ret = btrfs_run_delayed_items(trans); + if (ret) goto out_end_trans; /* @@ -5899,11 +6051,11 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) path->lowest_level = level; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); path->lowest_level = 0; - if (ret < 0) { - err = ret; + if (ret < 0) goto out_end_trans; - } + WARN_ON(ret > 0); + ret = 0; /* * unlock our path, this is safe because only this @@ -5916,14 +6068,17 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) btrfs_tree_lock(path->nodes[level]); path->locks[level] = BTRFS_WRITE_LOCK; + /* + * btrfs_lookup_extent_info() returns 0 for success, + * or < 0 for error. + */ ret = btrfs_lookup_extent_info(trans, fs_info, path->nodes[level]->start, level, 1, &wc->refs[level], &wc->flags[level], NULL); - if (ret < 0) { - err = ret; + if (ret < 0) goto out_end_trans; - } + BUG_ON(wc->refs[level] == 0); if (level == btrfs_root_drop_level(root_item)) @@ -5949,19 +6104,18 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) ret = walk_down_tree(trans, root, path, wc); if (ret < 0) { btrfs_abort_transaction(trans, ret); - err = ret; break; } ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL); if (ret < 0) { btrfs_abort_transaction(trans, ret); - err = ret; break; } if (ret > 0) { BUG_ON(wc->stage != DROP_REFERENCE); + ret = 0; break; } @@ -5983,7 +6137,6 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) root_item); if (ret) { btrfs_abort_transaction(trans, ret); - err = ret; goto out_end_trans; } @@ -5994,7 +6147,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) { btrfs_debug(fs_info, "drop snapshot early exit"); - err = -EAGAIN; + ret = -EAGAIN; goto out_free; } @@ -6008,19 +6161,18 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) else trans = btrfs_start_transaction(tree_root, 0); if (IS_ERR(trans)) { - err = PTR_ERR(trans); + ret = PTR_ERR(trans); goto out_free; } } } btrfs_release_path(path); - if (err) + if (ret) goto out_end_trans; ret = btrfs_del_root(trans, &root->root_key); if (ret) { btrfs_abort_transaction(trans, ret); - err = ret; goto out_end_trans; } @@ -6029,10 +6181,11 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) NULL, NULL); if (ret < 0) { btrfs_abort_transaction(trans, ret); - err = ret; goto out_end_trans; } else if (ret > 0) { - /* if we fail to delete the orphan item this time + ret = 0; + /* + * If we fail to delete the orphan item this time * around, it'll get picked up the next time. * * The most common failure here is just -ENOENT. @@ -6063,11 +6216,19 @@ out_free: kfree(wc); btrfs_free_path(path); out: + if (!ret && root_dropped) { + ret = btrfs_qgroup_cleanup_dropped_subvolume(fs_info, rootid); + if (ret < 0) + btrfs_warn_rl(fs_info, + "failed to cleanup qgroup 0/%llu: %d", + rootid, ret); + ret = 0; + } /* * We were an unfinished drop root, check to see if there are any * pending, and if not clear and wake up any waiters. */ - if (!err && unfinished_drop) + if (!ret && unfinished_drop) btrfs_maybe_wake_unfinished_drop(fs_info); /* @@ -6079,7 +6240,7 @@ out: */ if (!for_reloc && !root_dropped) btrfs_add_dead_root(root); - return err; + return ret; } /* |