From: Filipe Manana fdmanana@suse.com
commit 72bd2323ec87722c115a5906bc6a1b31d11e8f54 upstream.
Currently when we fail to COW a path at btrfs_update_root() we end up always aborting the transaction. However all the current callers of btrfs_update_root() are able to deal with errors returned from it, many do end up aborting the transaction themselves (directly or not, such as the transaction commit path), other BUG_ON() or just gracefully cancel whatever they were doing.
When syncing the fsync log, we call btrfs_update_root() through tree-log.c:update_log_root(), and if it returns an -ENOSPC error, the log sync code does not abort the transaction, instead it gracefully handles the error and returns -EAGAIN to the fsync handler, so that it falls back to a transaction commit. Any other error different from -ENOSPC, makes the log sync code abort the transaction.
So remove the transaction abort from btrfs_update_log() when we fail to COW a path to update the root item, so that if an -ENOSPC failure happens we avoid aborting the current transaction and have a chance of the fsync succeeding after falling back to a transaction commit.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203413 Fixes: 79787eaab46121 ("btrfs: replace many BUG_ONs with proper error handling") Cc: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana fdmanana@suse.com Reviewed-by: Anand Jain anand.jain@oracle.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/root-tree.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/fs/btrfs/root-tree.c +++ b/fs/btrfs/root-tree.c @@ -132,10 +132,8 @@ int btrfs_update_root(struct btrfs_trans return -ENOMEM;
ret = btrfs_search_slot(trans, root, key, path, 0, 1); - if (ret < 0) { - btrfs_abort_transaction(trans, ret); + if (ret < 0) goto out; - }
if (ret != 0) { btrfs_print_leaf(path->nodes[0]);