ceph: flush release queue when handling caps for unknown inode

BugLink: https://bugs.launchpad.net/bugs/1881927

[ Upstream commit fb33c11 ]

It's possible for the VFS to completely forget about an inode, but for
it to still be sitting on the cap release queue. If the MDS sends the
client a cap message for such an inode, it just ignores it today, which
can lead to a stall of up to 5s until the cap release queue is flushed.

If we get a cap message for an inode that can't be located, then go
ahead and flush the cap release queue.

Cc: [email protected]
URL: https://tracker.ceph.com/issues/45532
Fixes: 1e9c2eb ("ceph: delete stale dentry when last reference is dropped")
Reported-and-Tested-by: Andrej Filipčič <[email protected]>
Suggested-by: Yan, Zheng <[email protected]>
Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Ilya Dryomov <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
Signed-off-by: Khalid Elmously <[email protected]>

Author: jtlayton

fs/ceph/caps.c

@@ -3938,7 +3938,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
 			__ceph_queue_cap_release(session, cap);
 			spin_unlock(&session->s_cap_lock);
 		}
-		goto done;
+		goto flush_cap_releases;
 	}
 
 	/* these will work even if we don't have a cap yet */