[PATCH 4.4 35/41] btrfs: block-group: Fix a memory leak due to missing btrfs_put_block_group()

[Greg Kroah-Hartman]

From: Qu Wenruo <wqu@xxxxxxxx>

commit 4b654acdae850f48b8250b9a578a4eaa518c7a6f upstream.

In btrfs_read_block_groups(), if we have an invalid block group which
has mixed type (DATA|METADATA) while the fs doesn't have MIXED_GROUPS
feature, we error out without freeing the block group cache.

This patch will add the missing btrfs_put_block_group() to prevent
memory leak.

Note for stable backports: the file to patch in versions <= 5.3 is
fs/btrfs/extent-tree.c

Fixes: 49303381f19a ("Btrfs: bail out if block group has different mixed flag")
CC: stable@xxxxxxxxxxxxxxx # 4.9+
Reviewed-by: Anand Jain <anand.jain@xxxxxxxxxx>
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/btrfs/extent-tree.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9905,6 +9905,7 @@ int btrfs_read_block_groups(struct btrfs
 			btrfs_err(info,
 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
 				  cache->key.objectid);
+			btrfs_put_block_group(cache);
 			ret = -EINVAL;
 			goto error;
 		}