rbd: remove snapshot existence validation code
RBD_DEV_FLAG_EXISTS check in rbd_queue_workfn() is racy and leads to
inconsistent behaviour. If the object (or its snapshot) isn't there,
the OSD returns ENOENT. A read submitted before the snapshot removal
notification is processed would be zero-filled and ended with status
OK, while future reads would be failed with IOERR. It also doesn't
handle a case when an image that is mapped read-only is removed.
On top of this, because watch is no longer established for read-only
mappings, we no longer get notifications, so rbd_exists_validate() is
effectively dead code. While failing requests rather than returning
zeros is a good thing, RBD_DEV_FLAG_EXISTS is not it.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
1 file changed