linux-kernel - [PATCH 1/3] GFS2: force a log flush when invalidating the rindex glock

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Date:	Thu, 14 Jul 2011 09:21:54 +0100
From:	Steven Whitehouse <swhiteho@...hat.com>
To:	linux-kernel@...r.kernel.org, cluster-devel@...hat.com
Cc:	Benjamin Marzinski <bmarzins@...hat.com>,
	Steven Whitehouse <swhiteho@...hat.com>
Subject: [PATCH 1/3] GFS2: force a log flush when invalidating the rindex glock

From: Benjamin Marzinski <bmarzins@...hat.com>

Right now, there is nothing that forces the log to get flushed when a node
drops its rindex glock so that another node can grow the filesystem. If the
log doesn't get flushed, GFS2 can corrupt the sd_log_le_rg list in the
following way.

A node puts an rgd on the list in rg_lo_add(), and then the rindex glock is
dropped so the other node can grow the filesystem. When the node reacquires the
rindex glock, that rgd gets deleted in clear_rgrpdi() before ever being
removed from the list by gfs2_log_flush().

This code simply forces a log flush when the rindex glock is invalidated,
solving the problem.

Signed-off-by: Benjamin Marzinski <bmarzins@...hat.com>
Signed-off-by: Steven Whitehouse <swhiteho@...hat.com>

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 8ef70f4..712b722 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -221,8 +221,10 @@ static void inode_go_inval(struct gfs2_glock *gl, int flags)
 		}
 	}

-	if (ip == GFS2_I(gl->gl_sbd->sd_rindex))
+	if (ip == GFS2_I(gl->gl_sbd->sd_rindex)) {
+		gfs2_log_flush(gl->gl_sbd, NULL);
 		gl->gl_sbd->sd_rindex_uptodate = 0;
+	}
 	if (ip && S_ISREG(ip->i_inode.i_mode))
 		truncate_inode_pages(ip->i_inode.i_mapping, 0);
 }
-- 
1.7.4

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