linux-kernel - [PATCH 28/51] [GFS2] Patch to protect sd_log_num

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Message-Id: <11914878422398-git-send-email-swhiteho@redhat.com>
Date:	Thu,  4 Oct 2007 09:49:21 +0100
From:	swhiteho@...hat.com
To:	linux-kernel@...r.kernel.org, cluster-devel@...hat.com
Cc:	Bob Peterson <rpeterso@...hat.com>,
	Steven Whitehouse <swhiteho@...hat.com>
Subject: [PATCH 28/51] [GFS2] Patch to protect sd_log_num_jdata

From: Bob Peterson <rpeterso@...hat.com>

This is a patch to GFS2 to protect sd_log_num_jdata with the
gfs2_log_lock.  Without this patch, there is a timing window
where you can get hit the following assert from function
gfs2_log_flush():

gfs2_assert_withdraw(sdp,
			sdp->sd_log_num_buf + sdp->sd_log_num_jdata ==
			sdp->sd_log_commited_buf +
			sdp->sd_log_commited_databuf);

I've tested it on my roth cluster and it fixes the problem.

Signed-off-by: Bob Peterson <rpeterso@...hat.com>
Signed-off-by: Steven Whitehouse <swhiteho@...hat.com>

diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index a0371f8..7ef3356 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -492,11 +492,12 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
 
 	gfs2_trans_add_gl(bd->bd_gl);
 	if (gfs2_is_jdata(ip)) {
-		sdp->sd_log_num_jdata++;
 		gfs2_pin(sdp, bd->bd_bh);
 		tr->tr_num_databuf_new++;
 	}
 	gfs2_log_lock(sdp);
+	if (gfs2_is_jdata(ip))
+		sdp->sd_log_num_jdata++;
 	sdp->sd_log_num_databuf++;
 	list_add(&le->le_list, &sdp->sd_log_le_databuf);
 	gfs2_log_unlock(sdp);
-- 
1.5.1.2

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