btrfs: avoid double put of block group when emptying cluster

It's wrong calling btrfs_put_block_group in
__btrfs_return_cluster_to_free_space if the block group passed is
different than the block group the cluster represents. As this means the
cluster doesn't have a reference to the passed block group. This results
in double put and a use-after-free bug.

Fix this by simply bailing if the block group we passed in does not
match the block group on the cluster.

Fixes: fa9c0d795f7b ("Btrfs: rework allocation clustering")
CC: [email protected] # 4.4+
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
[ update changelog ]
Signed-off-by: David Sterba <[email protected]>

0 files changed, 0 insertions, 0 deletions