[PATCH] NLM: Ensure we do not Oops in the case of an unlock

In theory, NLM specs assure us that the server will only reply LCK_GRANTED or
LCK_DENIED_GRACE_PERIOD to our NLM_UNLOCK request.

In practice, we should not assume this to be the case, and the code will
currently Oops if we do.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 220058d8616d..970b6a6aa337 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -662,12 +662,18 @@ nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
          * reclaimed while we're stuck in the unlock call. */
         fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
 
+        /*
+         * Note: the server is supposed to either grant us the unlock
+         * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
+         * case, we want to unlock.
+         */
+        do_vfs_lock(fl);
+
         if (req->a_flags & RPC_TASK_ASYNC) {
                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
                                         &nlmclnt_unlock_ops);
                 /* Hrmf... Do the unlock early since locks_remove_posix()
                  * really expects us to free the lock synchronously */
-                do_vfs_lock(fl);
                 if (status < 0) {
                         nlmclnt_release_lockargs(req);
                         kfree(req);
@@ -680,7 +686,6 @@ nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
         if (status < 0)
                 return status;
 
-        do_vfs_lock(fl);
         if (resp->status == NLM_LCK_GRANTED)
                 return 0;