From: Abhijith Das <adas@redhat.com>
Date: Wed, 8 Sep 2010 21:56:46 -0400
Subject: [fs] dlm: fix try 1cb failure, part 2
Message-id: <23768002.1683941283983006115.JavaMail.root@zmail05.collab.prod.int.phx2.redhat.com>
Patchwork-id: 28182
O-Subject: Re: [RHEL5.6 PATCH] dlm: Don't send callback to node making lock
	request when "try 1cb" fails
Bugzilla: 504188
RH-Acked-by: Steven Whitehouse <swhiteho@redhat.com>
RH-Acked-by: Robert S Peterson <rpeterso@redhat.com>

part2 patch to bz 504188

dlm: Don't send callback to node making lock request when "try 1cb" fails

The patch introduces a new glock flag called the queued flag. This is set any
time a holder is queued on a glock. It is reset upon a state change which does
not involve the UN state occurs, and only then if there are no queued holders
at the time.

If the flag is not set, then the minimum hold time will not be obeyed. Instead
the demote will be scheduled immediately. If the flag is set, then the min hold
time will be obeyed as usual.

This patch combined with the dlm patch posted by Dave Teigland earlier improves
gfs2 performance for the test case in the bz greatly.

Resolves: rhbz#504188
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Tested-by: Abhi Das <adas@redhat.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 888d648..444fb3d 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -497,6 +497,8 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state)
 		else
 			gfs2_glock_put_nolock(gl);
 	}
+	if (held1 && held2 && list_empty(&gl->gl_holders))
+		clear_bit(GLF_QUEUED, &gl->gl_flags);
 
 	gl->gl_state = new_state;
 	gl->gl_tchange = jiffies;
@@ -1049,6 +1051,7 @@ fail:
 		if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
 			insert_pt = &gh2->gh_list;
 	}
+	set_bit(GLF_QUEUED, &gl->gl_flags);
 	if (likely(insert_pt == NULL)) {
 		list_add_tail(&gh->gh_list, &gl->gl_holders);
 		if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
@@ -1397,10 +1400,12 @@ static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
 		return;
 
 	holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
-	if (time_before(now, holdtime))
-		delay = holdtime - now;
-	if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
-		delay = gl->gl_ops->go_min_hold_time;
+	if (test_bit(GLF_QUEUED, &gl->gl_flags)) {
+		if (time_before(now, holdtime))
+			delay = holdtime - now;
+		if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
+			delay = gl->gl_ops->go_min_hold_time;
+	}
 
 	spin_lock(&gl->gl_spin);
 	handle_callback(gl, state, delay);
@@ -1729,6 +1734,8 @@ static const char *gflags2str(char *buf, const unsigned long *gflags)
 		*p++ = 'i';
 	if (test_bit(GLF_REPLY_PENDING, gflags))
 		*p++ = 'r';
+	if (test_bit(GLF_QUEUED, gflags))
+		*p++ = 'q';
 	*p = 0;
 	return buf;
 }
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index c62e974..1e5f8d8 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -164,6 +164,7 @@ enum {
 	GLF_LFLUSH			= 7,
 	GLF_INVALIDATE_IN_PROGRESS	= 8,
 	GLF_REPLY_PENDING		= 9,
+	GLF_QUEUED			= 12,
 };
 
 struct gfs2_glock {