[SRU] [Xenial] [PATCH 1/1] Btrfs: fix extent map leak during fallocate error path

[Andrea Righi]

From: Filipe Manana <fdmanana at suse.com>

BugLink: https://bugs.launchpad.net/bugs/1822579

If the call to btrfs_qgroup_reserve_data() failed, we were leaking an
extent map structure. The failure can happen either due to an -ENOMEM
condition or, when quotas are enabled, due to -EDQUOT for example.

Signed-off-by: Filipe Manana <fdmanana at suse.com>
Reviewed-by: David Sterba <dsterba at suse.com>
(backported from commit be2d253cc98244765323a7c94cc1ac5cd5a17072)
Signed-off-by: Andrea Righi <andrea.righi at canonical.com>
---
 fs/btrfs/file.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 751fcc6..743ad5e 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2763,8 +2763,10 @@ static long btrfs_fallocate(struct file *file, int mode,
 			}
 			ret = btrfs_qgroup_reserve_data(inode, cur_offset,
 					last_byte - cur_offset);
-			if (ret < 0)
+			if (ret < 0) {
+				free_extent_map(em);
 				break;
+			}
 		}
 		free_extent_map(em);
 		cur_offset = last_byte;
-- 
2.7.4