GFS2: recovery stuck on transaction lock

Hi,

This patch fixes bugzilla bug #590878: GFS2: recovery stuck on transaction lock. We set the frozen flag on the glock when we receive a completion that cannot be delivered due to blocked locks. At that point we check to see whether the first waiting holder has the noexp flag set. If the noexp lock is queued later, then we need to unfreeze the glock at that point in time, namely, in the glock work function.

This patch was originally written by Steve Whitehouse, but since he's on holiday, I'm submitting it. It's been well tested with a complex recovery test called revolver.

Regards,

Bob Peterson
Red Hat GFS

Signed-off-by Steve Whitehouse <[email protected]>

Signed-off-by Bob Peterson <[email protected]>

--

fs/gfs2/glock.c +10 -0

index ddcdbf4..dbab3fd 100644
@@ -706,8 +706,18 @@ static void glock_work_func(struct work_struct *work)
 {
 	unsigned long delay = 0;
 	struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
+	struct gfs2_holder *gh;
 	int drop_ref = 0;
 
+	if (unlikely(test_bit(GLF_FROZEN, &gl->gl_flags))) {
+		spin_lock(&gl->gl_spin);
+		gh = find_first_waiter(gl);
+		if (gh && (gh->gh_flags & LM_FLAG_NOEXP) &&
+		    test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
+			set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
+		spin_unlock(&gl->gl_spin);
+	}
+
 	if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
 		finish_xmote(gl, gl->gl_reply);
 		drop_ref = 1;