lockd: server should unlock lock if client rejects the grant

Currently lockd just dequeues the block and ignores it if the client
sends a GRANT_RES with a status of nlm_lck_denied. That status is an
indicator that the client has rejected the lock, so the right thing to
do is to unlock the lock we were trying to grant.

Reported-by: Yongcheng Yang <yoyang@redhat.com>
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2063818
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 4e30f3c50970127ea0a5197ed03b310f2409e3eb..c43ccdf28ed9117547a349eb3436ce9484d6b7b0 100644 (file)
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -954,19 +954,32 @@ void
 nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
 {
        struct nlm_block        *block;
+       struct file_lock        *fl;
+       int                     error;
 
        dprintk("grant_reply: looking for cookie %x, s=%d \n",
                *(unsigned int *)(cookie->data), status);
        if (!(block = nlmsvc_find_block(cookie)))
                return;
 
-       if (status == nlm_lck_denied_grace_period) {
+       switch (status) {
+       case nlm_lck_denied_grace_period:
                /* Try again in a couple of seconds */
                nlmsvc_insert_block(block, 10 * HZ);
-       } else {
+               break;
+       case nlm_lck_denied:
+               /* Client doesn't want it, just unlock it */
+               nlmsvc_unlink_block(block);
+               fl = &block->b_call->a_args.lock.fl;
+               fl->fl_type = F_UNLCK;
+               error = vfs_lock_file(fl->fl_file, F_SETLK, fl, NULL);
+               if (error)
+                       pr_warn("lockd: unable to unlock lock rejected by client!\n");
+               break;
+       default:
                /*
-                * Lock is now held by client, or has been rejected.
-                * In both cases, the block should be removed.
+                * Either it was accepted or the status makes no sense
+                * just unlink it either way.
                 */
                nlmsvc_unlink_block(block);
        }