[Cluster-devel] GFS2: don't hold s_umount over blkdev_put
Steven Whitehouse
swhiteho at redhat.com
Fri Dec 6 13:19:18 UTC 2013
>From babf8784061a4256b4c41073f9eabc0dd65f206a Mon Sep 17 00:00:00 2001
From: Steven Whitehouse <swhiteho at redhat.com>
Date: Fri, 6 Dec 2013 11:52:34 +0000
Subject: GFS2: don't hold s_umount over blkdev_put
This is a GFS2 version of Tejun's patch:
4f331f01b9c43bf001d3ffee578a97a1e0633eac
vfs: don't hold s_umount over close_bdev_exclusive() call
In this case its blkdev_put itself that is the issue and this
patch uses the same solution of dropping and retaking s_umount.
Reported-by: Tejun Heo <tj at kernel.org>
Reported-by: Al Viro <viro at ZenIV.linux.org.uk>
Signed-off-by: Steven Whitehouse <swhiteho at redhat.com>
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 82303b4..52fa883 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1366,8 +1366,18 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
if (IS_ERR(s))
goto error_bdev;
- if (s->s_root)
+ if (s->s_root) {
+ /*
+ * s_umount nests inside bd_mutex during
+ * __invalidate_device(). blkdev_put() acquires
+ * bd_mutex and can't be called under s_umount. Drop
+ * s_umount temporarily. This is safe as we're
+ * holding an active reference.
+ */
+ up_write(&s->s_umount);
blkdev_put(bdev, mode);
+ down_write(&s->s_umount);
+ }
memset(&args, 0, sizeof(args));
args.ar_quota = GFS2_QUOTA_DEFAULT;
--
1.8.3.1
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