| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 125/144] GFS2: dont hold s_umount over blkdev_put | Date | Mon, 6 Jan 2014 14:38:06 -0800 |
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3.12-stable review patch. If anyone has any objections, please let me know.
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From: Steven Whitehouse <swhiteho@redhat.com>
commit dfe5b9ad83a63180f358b27d1018649a27b394a9 upstream.
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@kernel.org> Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/gfs2/ops_fstype.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
--- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -1366,8 +1366,18 @@ static struct dentry *gfs2_mount(struct 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;
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