From: Steven Whitehouse Date: Fri, 6 Dec 2013 11:52:34 +0000 (+0000) Subject: GFS2: don't hold s_umount over blkdev_put X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=21b6291b88c534d8c6018ad483e232abab63f644;p=linux-edison.git GFS2: don't hold s_umount over blkdev_put 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 Reported-by: Al Viro Signed-off-by: Steven Whitehouse Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index 60ede2a0f43..f7dd3b4f8ab 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -1317,8 +1317,18 @@ 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;