Reason for this is that btrfs_shrink_device adds the resized device to
the fs_devices::resized_devices after it has called the last commit
transaction.
So the list fs_devices::resized_devices is not empty when
btrfs_shrink_device returns. Now the parent function
btrfs_rm_device calls:
and then does the transactio ncommit. It goes through the
fs_devices::resized_devices in btrfs_update_commit_device_size and
leads to use-after-free.
Fix this by making sure btrfs_shrink_device calls the last needed
btrfs_commit_transaction before the return. This is consistent with what
the grow counterpart does and this makes sure the on-disk state is
persistent when the function returns.
Reported-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> Tested-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>