Btrfs: remove rcu_barrier in btrfs_close_devices

It was introduced because btrfs used to do blkdev_put in a deferred
work, now that btrfs has blkdev_put in place, this rcu_barrier can be
removed.

modprobe -r btrfs will do btrfs_cleanup_fs_uuids(), where it cleanup
every %fs_devices on the list, but when we do btrfs_close_devices(), we
have replaced the devices on the list with dummy ones which only have
the same name and uuid, so modprobe -r btrfs will free those instead of
what we were using, this change won't cause a problem for it.

Signed-off-by: Liu Bo <[email protected]>
Reviewed-by: Anand Jain <[email protected]>
Reviewed-by: David Sterba <[email protected]>
[ copied 2nd paragraph from mailinglist discussion ]
Signed-off-by: David Sterba <[email protected]>

0 files changed, 0 insertions, 0 deletions