md-cluster: fix potential lock issue in add_new_disk

The add_new_disk returns with communication locked if
__sendmsg returns failure, fix it with call unlock_comm
before return.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
CC: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 7299ce2..03082e1 100644 (file)
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -1311,8 +1311,10 @@ static int add_new_disk(struct mddev *mddev, struct md_rdev *rdev)
        cmsg.raid_slot = cpu_to_le32(rdev->desc_nr);
        lock_comm(cinfo, 1);
        ret = __sendmsg(cinfo, &cmsg);
-       if (ret)
+       if (ret) {
+               unlock_comm(cinfo);
                return ret;
+       }
        cinfo->no_new_dev_lockres->flags |= DLM_LKF_NOQUEUE;
        ret = dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_EX);
        cinfo->no_new_dev_lockres->flags &= ~DLM_LKF_NOQUEUE;