[PATCH 4.9 078/177] Btrfs: fix extent map leak during fallocate error path

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Filipe Manana <fdmanana@xxxxxxxx>


[ Upstream commit be2d253cc98244765323a7c94cc1ac5cd5a17072 ]

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@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/btrfs/file.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2817,8 +2817,10 @@ static long btrfs_fallocate(struct file
 			}
 			ret = btrfs_qgroup_reserve_data(inode, cur_offset,
 					last_byte - cur_offset);
-			if (ret < 0)
+			if (ret < 0) {
+				free_extent_map(em);
 				break;
+			}
 		} else {
 			/*
 			 * Do not need to reserve unwritten extent for this