diff --git a/Documentation/filesystems/btrfs.rst b/Documentation/filesystems/btrfs.rst index 992eddb..a81db8f 100644 --- a/Documentation/filesystems/btrfs.rst +++ b/Documentation/filesystems/btrfs.rst @@ -37,7 +37,6 @@ For more information please refer to the documentation site or wiki https://btrfs.readthedocs.io - https://btrfs.wiki.kernel.org that maintains information about administration tasks, frequently asked questions, use cases, mount options, comprehensible changelogs, features, diff --git a/MAINTAINERS b/MAINTAINERS index 90f1328..79630b7 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4378,7 +4378,6 @@ M: David Sterba L: linux-btrfs@vger.kernel.org S: Maintained W: https://btrfs.readthedocs.io -W: https://btrfs.wiki.kernel.org/ Q: https://patchwork.kernel.org/project/linux-btrfs/list/ C: irc://irc.libera.chat/btrfs T: git git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig index 3282adc..a25c991 100644 --- a/fs/btrfs/Kconfig +++ b/fs/btrfs/Kconfig @@ -31,7 +31,7 @@ config BTRFS_FS continue to be mountable and usable by newer kernels. For more information, please see the web pages at - http://btrfs.wiki.kernel.org. + https://btrfs.readthedocs.io To compile this file system support as a module, choose M here. The module will be called btrfs. diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 0cb1dee..b2e5107 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -3028,8 +3028,16 @@ static int update_block_group_item(struct btrfs_trans_handle *trans, btrfs_mark_buffer_dirty(leaf); fail: btrfs_release_path(path); - /* We didn't update the block group item, need to revert @commit_used. */ - if (ret < 0) { + /* + * We didn't update the block group item, need to revert commit_used + * unless the block group item didn't exist yet - this is to prevent a + * race with a concurrent insertion of the block group item, with + * insert_block_group_item(), that happened just after we attempted to + * update. In that case we would reset commit_used to 0 just after the + * insertion set it to a value greater than 0 - if the block group later + * becomes with 0 used bytes, we would incorrectly skip its update. + */ + if (ret < 0 && ret != -ENOENT) { spin_lock(&cache->lock); cache->commit_used = old_commit_used; spin_unlock(&cache->lock); diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c index 53c1211..caf0bbd 100644 --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -412,6 +412,7 @@ static void finish_one_item(struct btrfs_delayed_root *delayed_root) static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item) { + struct btrfs_delayed_node *delayed_node = delayed_item->delayed_node; struct rb_root_cached *root; struct btrfs_delayed_root *delayed_root; @@ -419,18 +420,21 @@ static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item) if (RB_EMPTY_NODE(&delayed_item->rb_node)) return; - delayed_root = delayed_item->delayed_node->root->fs_info->delayed_root; + /* If it's in a rbtree, then we need to have delayed node locked. */ + lockdep_assert_held(&delayed_node->mutex); + + delayed_root = delayed_node->root->fs_info->delayed_root; BUG_ON(!delayed_root); if (delayed_item->type == BTRFS_DELAYED_INSERTION_ITEM) - root = &delayed_item->delayed_node->ins_root; + root = &delayed_node->ins_root; else - root = &delayed_item->delayed_node->del_root; + root = &delayed_node->del_root; rb_erase_cached(&delayed_item->rb_node, root); RB_CLEAR_NODE(&delayed_item->rb_node); - delayed_item->delayed_node->count--; + delayed_node->count--; finish_one_item(delayed_root); } @@ -1153,20 +1157,33 @@ static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr) ret = __btrfs_commit_inode_delayed_items(trans, path, curr_node); if (ret) { - btrfs_release_delayed_node(curr_node); - curr_node = NULL; btrfs_abort_transaction(trans, ret); break; } prev_node = curr_node; curr_node = btrfs_next_delayed_node(curr_node); + /* + * See the comment below about releasing path before releasing + * node. If the commit of delayed items was successful the path + * should always be released, but in case of an error, it may + * point to locked extent buffers (a leaf at the very least). + */ + ASSERT(path->nodes[0] == NULL); btrfs_release_delayed_node(prev_node); } + /* + * Release the path to avoid a potential deadlock and lockdep splat when + * releasing the delayed node, as that requires taking the delayed node's + * mutex. If another task starts running delayed items before we take + * the mutex, it will first lock the mutex and then it may try to lock + * the same btree path (leaf). + */ + btrfs_free_path(path); + if (curr_node) btrfs_release_delayed_node(curr_node); - btrfs_free_path(path); trans->block_rsv = block_rsv; return ret; @@ -1413,7 +1430,29 @@ void btrfs_balance_delayed_items(struct btrfs_fs_info *fs_info) btrfs_wq_run_delayed_node(delayed_root, fs_info, BTRFS_DELAYED_BATCH); } -/* Will return 0 or -ENOMEM */ +static void btrfs_release_dir_index_item_space(struct btrfs_trans_handle *trans) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, 1); + + if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) + return; + + /* + * Adding the new dir index item does not require touching another + * leaf, so we can release 1 unit of metadata that was previously + * reserved when starting the transaction. This applies only to + * the case where we had a transaction start and excludes the + * transaction join case (when replaying log trees). + */ + trace_btrfs_space_reservation(fs_info, "transaction", + trans->transid, bytes, 0); + btrfs_block_rsv_release(fs_info, trans->block_rsv, bytes, NULL); + ASSERT(trans->bytes_reserved >= bytes); + trans->bytes_reserved -= bytes; +} + +/* Will return 0, -ENOMEM or -EEXIST (index number collision, unexpected). */ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, const char *name, int name_len, struct btrfs_inode *dir, @@ -1455,6 +1494,27 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, mutex_lock(&delayed_node->mutex); + /* + * First attempt to insert the delayed item. This is to make the error + * handling path simpler in case we fail (-EEXIST). There's no risk of + * any other task coming in and running the delayed item before we do + * the metadata space reservation below, because we are holding the + * delayed node's mutex and that mutex must also be locked before the + * node's delayed items can be run. + */ + ret = __btrfs_add_delayed_item(delayed_node, delayed_item); + if (unlikely(ret)) { + btrfs_err(trans->fs_info, +"error adding delayed dir index item, name: %.*s, index: %llu, root: %llu, dir: %llu, dir->index_cnt: %llu, delayed_node->index_cnt: %llu, error: %d", + name_len, name, index, btrfs_root_id(delayed_node->root), + delayed_node->inode_id, dir->index_cnt, + delayed_node->index_cnt, ret); + btrfs_release_delayed_item(delayed_item); + btrfs_release_dir_index_item_space(trans); + mutex_unlock(&delayed_node->mutex); + goto release_node; + } + if (delayed_node->index_item_leaves == 0 || delayed_node->curr_index_batch_size + data_len > leaf_data_size) { delayed_node->curr_index_batch_size = data_len; @@ -1472,36 +1532,14 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, * impossible. */ if (WARN_ON(ret)) { - mutex_unlock(&delayed_node->mutex); btrfs_release_delayed_item(delayed_item); + mutex_unlock(&delayed_node->mutex); goto release_node; } delayed_node->index_item_leaves++; - } else if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) { - const u64 bytes = btrfs_calc_insert_metadata_size(fs_info, 1); - - /* - * Adding the new dir index item does not require touching another - * leaf, so we can release 1 unit of metadata that was previously - * reserved when starting the transaction. This applies only to - * the case where we had a transaction start and excludes the - * transaction join case (when replaying log trees). - */ - trace_btrfs_space_reservation(fs_info, "transaction", - trans->transid, bytes, 0); - btrfs_block_rsv_release(fs_info, trans->block_rsv, bytes, NULL); - ASSERT(trans->bytes_reserved >= bytes); - trans->bytes_reserved -= bytes; - } - - ret = __btrfs_add_delayed_item(delayed_node, delayed_item); - if (unlikely(ret)) { - btrfs_err(trans->fs_info, - "err add delayed dir index item(name: %.*s) into the insertion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)", - name_len, name, delayed_node->root->root_key.objectid, - delayed_node->inode_id, ret); - BUG(); + } else { + btrfs_release_dir_index_item_space(trans); } mutex_unlock(&delayed_node->mutex); diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 0a96ea8..68f60d5 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -520,6 +520,7 @@ static bool btree_dirty_folio(struct address_space *mapping, struct folio *folio) { struct btrfs_fs_info *fs_info = btrfs_sb(mapping->host->i_sb); + struct btrfs_subpage_info *spi = fs_info->subpage_info; struct btrfs_subpage *subpage; struct extent_buffer *eb; int cur_bit = 0; @@ -533,18 +534,19 @@ static bool btree_dirty_folio(struct address_space *mapping, btrfs_assert_tree_write_locked(eb); return filemap_dirty_folio(mapping, folio); } + + ASSERT(spi); subpage = folio_get_private(folio); - ASSERT(subpage->dirty_bitmap); - while (cur_bit < BTRFS_SUBPAGE_BITMAP_SIZE) { + for (cur_bit = spi->dirty_offset; + cur_bit < spi->dirty_offset + spi->bitmap_nr_bits; + cur_bit++) { unsigned long flags; u64 cur; - u16 tmp = (1 << cur_bit); spin_lock_irqsave(&subpage->lock, flags); - if (!(tmp & subpage->dirty_bitmap)) { + if (!test_bit(cur_bit, subpage->bitmaps)) { spin_unlock_irqrestore(&subpage->lock, flags); - cur_bit++; continue; } spin_unlock_irqrestore(&subpage->lock, flags); @@ -557,7 +559,7 @@ static bool btree_dirty_folio(struct address_space *mapping, btrfs_assert_tree_write_locked(eb); free_extent_buffer(eb); - cur_bit += (fs_info->nodesize >> fs_info->sectorsize_bits); + cur_bit += (fs_info->nodesize >> fs_info->sectorsize_bits) - 1; } return filemap_dirty_folio(mapping, folio); } @@ -1547,7 +1549,7 @@ static int transaction_kthread(void *arg) delta = ktime_get_seconds() - cur->start_time; if (!test_and_clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags) && - cur->state < TRANS_STATE_COMMIT_START && + cur->state < TRANS_STATE_COMMIT_PREP && delta < fs_info->commit_interval) { spin_unlock(&fs_info->trans_lock); delay -= msecs_to_jiffies((delta - 1) * 1000); @@ -2682,8 +2684,8 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info) btrfs_lockdep_init_map(fs_info, btrfs_trans_num_extwriters); btrfs_lockdep_init_map(fs_info, btrfs_trans_pending_ordered); btrfs_lockdep_init_map(fs_info, btrfs_ordered_extent); - btrfs_state_lockdep_init_map(fs_info, btrfs_trans_commit_start, - BTRFS_LOCKDEP_TRANS_COMMIT_START); + btrfs_state_lockdep_init_map(fs_info, btrfs_trans_commit_prep, + BTRFS_LOCKDEP_TRANS_COMMIT_PREP); btrfs_state_lockdep_init_map(fs_info, btrfs_trans_unblocked, BTRFS_LOCKDEP_TRANS_UNBLOCKED); btrfs_state_lockdep_init_map(fs_info, btrfs_trans_super_committed, @@ -4870,7 +4872,7 @@ static int btrfs_cleanup_transaction(struct btrfs_fs_info *fs_info) while (!list_empty(&fs_info->trans_list)) { t = list_first_entry(&fs_info->trans_list, struct btrfs_transaction, list); - if (t->state >= TRANS_STATE_COMMIT_START) { + if (t->state >= TRANS_STATE_COMMIT_PREP) { refcount_inc(&t->use_count); spin_unlock(&fs_info->trans_lock); btrfs_wait_for_commit(fs_info, t->transid); diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index a18ee7b..75ab766 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1958,6 +1958,13 @@ static int btrfs_search_path_in_tree_user(struct mnt_idmap *idmap, goto out_put; } + /* + * We don't need the path anymore, so release it and + * avoid deadlocks and lockdep warnings in case + * btrfs_iget() needs to lookup the inode from its root + * btree and lock the same leaf. + */ + btrfs_release_path(path); temp_inode = btrfs_iget(sb, key2.objectid, root); if (IS_ERR(temp_inode)) { ret = PTR_ERR(temp_inode); @@ -1978,7 +1985,6 @@ static int btrfs_search_path_in_tree_user(struct mnt_idmap *idmap, goto out_put; } - btrfs_release_path(path); key.objectid = key.offset; key.offset = (u64)-1; dirid = key.objectid; diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h index edb9b4a..7d6ee1e 100644 --- a/fs/btrfs/locking.h +++ b/fs/btrfs/locking.h @@ -79,7 +79,7 @@ enum btrfs_lock_nesting { }; enum btrfs_lockdep_trans_states { - BTRFS_LOCKDEP_TRANS_COMMIT_START, + BTRFS_LOCKDEP_TRANS_COMMIT_PREP, BTRFS_LOCKDEP_TRANS_UNBLOCKED, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED, BTRFS_LOCKDEP_TRANS_COMPLETED, diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index b46ab34..345c449 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -639,7 +639,7 @@ void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode, refcount_inc(&trans->use_count); spin_unlock(&fs_info->trans_lock); - ASSERT(trans); + ASSERT(trans || BTRFS_FS_ERROR(fs_info)); if (trans) { if (atomic_dec_and_test(&trans->pending_ordered)) wake_up(&trans->pending_wait); diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 874e439..0bf42dc 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -56,12 +56,17 @@ static struct kmem_cache *btrfs_trans_handle_cachep; * | Call btrfs_commit_transaction() on any trans handle attached to * | transaction N * V - * Transaction N [[TRANS_STATE_COMMIT_START]] + * Transaction N [[TRANS_STATE_COMMIT_PREP]] + * | + * | If there are simultaneous calls to btrfs_commit_transaction() one will win + * | the race and the rest will wait for the winner to commit the transaction. + * | + * | The winner will wait for previous running transaction to completely finish + * | if there is one. * | - * | Will wait for previous running transaction to completely finish if there - * | is one + * Transaction N [[TRANS_STATE_COMMIT_START]] * | - * | Then one of the following happes: + * | Then one of the following happens: * | - Wait for all other trans handle holders to release. * | The btrfs_commit_transaction() caller will do the commit work. * | - Wait for current transaction to be committed by others. @@ -112,6 +117,7 @@ static struct kmem_cache *btrfs_trans_handle_cachep; */ static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { [TRANS_STATE_RUNNING] = 0U, + [TRANS_STATE_COMMIT_PREP] = 0U, [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH), [TRANS_STATE_COMMIT_DOING] = (__TRANS_START | __TRANS_ATTACH | @@ -1982,7 +1988,7 @@ void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans) * Wait for the current transaction commit to start and block * subsequent transaction joins */ - btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START); + btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); wait_event(fs_info->transaction_blocked_wait, cur_trans->state >= TRANS_STATE_COMMIT_START || TRANS_ABORTED(cur_trans)); @@ -2129,7 +2135,7 @@ static void add_pending_snapshot(struct btrfs_trans_handle *trans) return; lockdep_assert_held(&trans->fs_info->trans_lock); - ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_START); + ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_PREP); list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots); } @@ -2153,7 +2159,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) ktime_t interval; ASSERT(refcount_read(&trans->use_count) == 1); - btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START); + btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags); @@ -2213,7 +2219,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) } spin_lock(&fs_info->trans_lock); - if (cur_trans->state >= TRANS_STATE_COMMIT_START) { + if (cur_trans->state >= TRANS_STATE_COMMIT_PREP) { enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; add_pending_snapshot(trans); @@ -2225,7 +2231,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) want_state = TRANS_STATE_SUPER_COMMITTED; btrfs_trans_state_lockdep_release(fs_info, - BTRFS_LOCKDEP_TRANS_COMMIT_START); + BTRFS_LOCKDEP_TRANS_COMMIT_PREP); ret = btrfs_end_transaction(trans); wait_for_commit(cur_trans, want_state); @@ -2237,9 +2243,9 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) return ret; } - cur_trans->state = TRANS_STATE_COMMIT_START; + cur_trans->state = TRANS_STATE_COMMIT_PREP; wake_up(&fs_info->transaction_blocked_wait); - btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START); + btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); if (cur_trans->list.prev != &fs_info->trans_list) { enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; @@ -2260,11 +2266,9 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) btrfs_put_transaction(prev_trans); if (ret) goto lockdep_release; - } else { - spin_unlock(&fs_info->trans_lock); + spin_lock(&fs_info->trans_lock); } } else { - spin_unlock(&fs_info->trans_lock); /* * The previous transaction was aborted and was already removed * from the list of transactions at fs_info->trans_list. So we @@ -2272,11 +2276,16 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) * corrupt state (pointing to trees with unwritten nodes/leafs). */ if (BTRFS_FS_ERROR(fs_info)) { + spin_unlock(&fs_info->trans_lock); ret = -EROFS; goto lockdep_release; } } + cur_trans->state = TRANS_STATE_COMMIT_START; + wake_up(&fs_info->transaction_blocked_wait); + spin_unlock(&fs_info->trans_lock); + /* * Get the time spent on the work done by the commit thread and not * the time spent waiting on a previous commit @@ -2586,7 +2595,7 @@ lockdep_release: goto cleanup_transaction; lockdep_trans_commit_start_release: - btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START); + btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP); btrfs_end_transaction(trans); return ret; } diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index 8e9fa23..6b309f8 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -14,6 +14,7 @@ enum btrfs_trans_state { TRANS_STATE_RUNNING, + TRANS_STATE_COMMIT_PREP, TRANS_STATE_COMMIT_START, TRANS_STATE_COMMIT_DOING, TRANS_STATE_UNBLOCKED,