From: David Teigland <teigland@redhat.com>
Date: Wed, 4 Apr 2012 14:49:15 +0000 (-0500)
Subject: dlm: fix QUECVT when convert queue is empty
X-Git-Tag: firefly_0821_release~3680^2~3015^2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=53ad1c980d4fb450722a575ca17c188808939340;p=firefly-linux-kernel-4.4.55.git

dlm: fix QUECVT when convert queue is empty

The QUECVT flag should not prevent conversions from
being granted immediately when the convert queue is
empty.

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

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index fa5c07d51dcc..4c58d4a3adc4 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1736,6 +1736,18 @@ static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
 	if (now && conv && !(lkb->lkb_exflags & DLM_LKF_QUECVT))
 		return 1;
 
+	/*
+	 * Even if the convert is compat with all granted locks,
+	 * QUECVT forces it behind other locks on the convert queue.
+	 */
+
+	if (now && conv && (lkb->lkb_exflags & DLM_LKF_QUECVT)) {
+		if (list_empty(&r->res_convertqueue))
+			return 1;
+		else
+			goto out;
+	}
+
 	/*
 	 * The NOORDER flag is set to avoid the standard vms rules on grant
 	 * order.