From: David Teigland <teigland@redhat.com>
Date: Thu, 5 Jun 2008 14:10:57 -0500
Subject: [dlm] fix basts for granted CW waiting PR/CW
Message-id: 20080605191057.GQ18635@redhat.com
O-Subject: [RHEL5.3 PATCH 17/18] dlm: fix basts for granted CW waiting PR/CW
Bugzilla: 450137
RH-Acked-by: Bob Peterson <rpeterso@redhat.com>

bz 450137  dlm: fix basts for granted CW waiting PR/CW

brew build including this patch
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1344633

upstream commit in linux-next, merge pending for 2.6.27:

>From: David Teigland <teigland@redhat.com>
>Date: Tue, 20 May 2008 12:18:10 -0500
>Subject: [PATCH] dlm: fix basts for granted CW waiting PR/CW

The fix in commit 3650925893469ccb03dbcc6a440c5d363350f591 was addressing
the case of a granted PR lock with waiting PR and CW locks.  It's a
special case that requires forcing a CW bast.  However, that forced CW
bast was incorrectly applying to a second condition where the granted
lock was CW.  So, the holder of a CW lock could receive an extraneous CW
bast instead of a PR bast.  This fix narrows the original special case to
what was intended.

Signed-off-by: David Teigland <teigland@redhat.com>

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index ea6a136..cd2b2cf 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1777,7 +1777,8 @@ static void grant_pending_locks(struct dlm_rsb *r)
 
 	list_for_each_entry_safe(lkb, s, &r->res_grantqueue, lkb_statequeue) {
 		if (lkb->lkb_bastaddr && lock_requires_bast(lkb, high, cw)) {
-			if (cw && high == DLM_LOCK_PR)
+			if (cw && high == DLM_LOCK_PR &&
+			    lkb->lkb_grmode == DLM_LOCK_PR)
 				queue_bast(r, lkb, DLM_LOCK_CW);
 			else
 				queue_bast(r, lkb, high);