[3.19.y-ckt stable] Patch "Revert "libceph: clear r_req_lru_item in __unregister_linger_request()"" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    Revert "libceph: clear r_req_lru_item in __unregister_linger_request()"

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 13dfd6deaee43bc203e03b99fb4409a78442a405 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov at gmail.com>
Date: Mon, 11 May 2015 17:53:34 +0300
Subject: Revert "libceph: clear r_req_lru_item in
 __unregister_linger_request()"

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.

Signed-off-by: Ilya Dryomov <idryomov at gmail.com>
Reviewed-by: Sage Weil <sage at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/ceph/osd_client.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 4d4be9b..9871411 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -1305,8 +1305,6 @@ static void __unregister_linger_request(struct ceph_osd_client *osdc,
 		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);
 }

--
1.9.1