Patch "Revert "libceph: clear r_req_lru_item in __unregister_linger_request()"" has been added to the 4.0-stable tree

This is a note to let you know that I've just added the patch titled

Revert "libceph: clear r_req_lru_item in __unregister_linger_request()"

to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
revert-libceph-clear-r_req_lru_item-in-__unregister_linger_request.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ilya Dryomov <[email protected]>
Date: Mon, 11 May 2015 17:53:34 +0300
Subject: Revert "libceph: clear r_req_lru_item in __unregister_linger_request()"

From: Ilya Dryomov <[email protected]>

commit 521a04d06a729e5971cdee7f84080387ed320527 upstream.

This reverts commit ba9d114ec5578e6e99a4dfa37ff8ae688040fd64.

.. which introduced a regression that prevented all lingering requests requeued in kick_requests() from ever being sent to the OSDs, resulting in a lot of missed notifies. In retrospect it's pretty obvious that r_req_lru_item item in the case of lingering requests can be used not only for notarget, but also for unsent linkage due to how tightly actual map and enqueue operations are coupled in __map_request().

The assertion that was being silenced is taken care of in the previous ("libceph: request a new osdmap if lingering request maps to no osd")
commit: by always kicking homeless lingering requests we ensure that none of them ends up on the notarget list outside of the critical section guarded by request_mutex.

---
 net/ceph/osd_client.c |    2 --
 1 file changed, 2 deletions(-)

@@ -1306,8 +1306,6 @@ static void __unregister_linger_request(
 		if (list_empty(&req->r_osd_item))
 			req->r_osd = NULL;
 	}
-
-	list_del_init(&req->r_req_lru_item); /* can be on notarget */
 	ceph_osdc_put_request(req);
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.0/libceph-request-a-new-osdmap-if-lingering-request-maps-to-no-osd.patch queue-4.0/revert-libceph-clear-r_req_lru_item-in-__unregister_linger_request.patch