From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:35910 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750780AbcGLSVd (ORCPT ); Tue, 12 Jul 2016 14:21:33 -0400 From: Liu Bo To: linux-btrfs@vger.kernel.org Cc: David Sterba , Chris Mason , Filipe Manana Subject: [PATCH v3] Btrfs: fix unexpected balance crash due to BUG_ON Date: Tue, 12 Jul 2016 11:24:21 -0700 Message-Id: <1468347861-16930-1-git-send-email-bo.li.liu@oracle.com> In-Reply-To: <1468257695-22445-1-git-send-email-bo.li.liu@oracle.com> References: <1468257695-22445-1-git-send-email-bo.li.liu@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: Mounting a btrfs can resume previous balance operations asynchronously. An user got a crash when one drive has some corrupt sectors. Since balance can cancel itself in case of any error, we can gracefully return errors to upper layers and let balance do the cancel job. Reported-by: sash Signed-off-by: Liu Bo --- v2: - Initialize path with NULL. - Show more information when we bail out. v3: - Fix typo - Use rcu version btrfs_info - Remove __func__ and __LINE__ fs/btrfs/volumes.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 589f128..6040c26 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -3421,7 +3421,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) u64 size_to_free; u64 chunk_type; struct btrfs_chunk *chunk; - struct btrfs_path *path; + struct btrfs_path *path = NULL; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_trans_handle *trans; @@ -3455,13 +3455,33 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) ret = btrfs_shrink_device(device, old_size - size_to_free); if (ret == -ENOSPC) break; - BUG_ON(ret); + if (ret) { + /* btrfs_shrink_device never returns ret > 0 */ + WARN_ON(ret > 0); + goto error; + } trans = btrfs_start_transaction(dev_root, 0); - BUG_ON(IS_ERR(trans)); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + btrfs_info_in_rcu(fs_info, + "resize: unable to start transaction after shrinking device %s (error %d), old size %llu, new size %llu", + rcu_str_deref(device->name), ret, + old_size, old_size - size_to_free); + goto error; + } ret = btrfs_grow_device(trans, device, old_size); - BUG_ON(ret); + if (ret) { + btrfs_end_transaction(trans, dev_root); + /* btrfs_grow_device never returns ret > 0 */ + WARN_ON(ret > 0); + btrfs_info_in_rcu(fs_info, + "resize: unable to grow device after shrinking device %s (error %d), old size %llu, new size %llu", + rcu_str_deref(device->name), ret, + old_size, old_size - size_to_free); + goto error; + } btrfs_end_transaction(trans, dev_root); } -- 2.5.5