Hi,

Thanks for pointing out this issue. I'm not sure how that got missed,
except that this code is used only for a debugging interface and so far
the focus has been on other glock types. Either way we should fix it,
and the following patch should solve the issue,

Steve.



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>From 134669854e3a680d8aad9a4047891c653715f4c0 Mon Sep 17 00:00:00 2001
From: Steven Whitehouse <swhiteho@redhat.com>
Date: Wed, 6 Oct 2010 09:58:44 +0100
Subject: [PATCH] GFS2: Fix type mapping for demote_rq interface

Mostly the glock operations follow the type of the glock. The
one exception is the transaction glock, so we need to check for
that directly.

Reported-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 621d80e..0d149dc 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -452,7 +452,6 @@ const struct gfs2_glock_operations *gfs2_glops_list[] = {
[LM_TYPE_META] = &gfs2_meta_glops,
[LM_TYPE_INODE] = &gfs2_inode_glops,
[LM_TYPE_RGRP] = &gfs2_rgrp_glops,
- [LM_TYPE_NONDISK] = &gfs2_trans_glops,
[LM_TYPE_IOPEN] = &gfs2_iopen_glops,
[LM_TYPE_FLOCK] = &gfs2_flock_glops,
[LM_TYPE_NONDISK] = &gfs2_nondisk_glops,
diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c
index 64082a5..748ccb5 100644
--- a/fs/gfs2/sys.c
+++ b/fs/gfs2/sys.c
@@ -230,7 +230,10 @@ static ssize_t demote_rq_store(struct gfs2_sbd *sdp, const char *buf, size_t len

if (gltype > LM_TYPE_JOURNAL)
return -EINVAL;
- glops = gfs2_glops_list[gltype];
+ if (gltype == LM_TYPE_NONDISK && glnum == GFS2_TRANS_LOCK)
+ glops = &gfs2_trans_glops;
+ else
+ glops = gfs2_glops_list[gltype];
if (glops == NULL)
return -EINVAL;
if (!test_and_set_bit(SDF_DEMOTE, &sdp->sd_flags))
--
1.7.1.1