NLM,NFSv4: Don't put UNLOCK requests on the wire unless we hold a lock

Use the new behaviour of {flock,posix}_file_lock(F_UNLCK) to determine if
we held a lock, and only send the RPC request to the server if this was the
case.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 22 insertions, 27 deletions

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 5980c45998cc..24c691f5480e 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -454,7 +454,7 @@ static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *ho
         fl->fl_ops = &nlmclnt_lock_ops;
 }
 
-static void do_vfs_lock(struct file_lock *fl)
+static int do_vfs_lock(struct file_lock *fl)
 {
         int res = 0;
         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
@@ -467,9 +467,7 @@ static void do_vfs_lock(struct file_lock *fl)
                 default:
                         BUG();
         }
-        if (res < 0)
-                printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
-                                __FUNCTION__);
+        return res;
 }
 
 /*
@@ -541,7 +539,8 @@ again:
                 }
                 fl->fl_flags |= FL_SLEEP;
                 /* Ensure the resulting lock will get added to granted list */
-                do_vfs_lock(fl);
+                if (do_vfs_lock(fl) < 0)
+                        printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
                 up_read(&host->h_rwsem);
         }
         status = nlm_stat_to_errno(resp->status);
@@ -606,15 +605,19 @@ nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 {
         struct nlm_host *host = req->a_host;
         struct nlm_res  *resp = &req->a_res;
-        int             status;
+        int status = 0;
 
         /*
          * 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.
          */
+        fl->fl_flags |= FL_EXISTS;
         down_read(&host->h_rwsem);
-        do_vfs_lock(fl);
+        if (do_vfs_lock(fl) == -ENOENT) {
+                up_read(&host->h_rwsem);
+                goto out;
+        }
         up_read(&host->h_rwsem);
 
         if (req->a_flags & RPC_TASK_ASYNC)
@@ -624,7 +627,6 @@ nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
         if (status < 0)
                 goto out;
 
-        status = 0;
         if (resp->status == NLM_LCK_GRANTED)
                 goto out;
 
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index b4916b092194..b8c63757f039 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3144,9 +3144,6 @@ static int do_vfs_lock(struct file *file, struct file_lock *fl)
                 default:
                         BUG();
         }
-        if (res < 0)
-                printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
-                                __FUNCTION__);
         return res;
 }
 
@@ -3258,8 +3255,6 @@ static struct rpc_task *nfs4_do_unlck(struct file_lock *fl,
                 return ERR_PTR(-ENOMEM);
         }
 
-        /* Unlock _before_ we do the RPC call */
-        do_vfs_lock(fl->fl_file, fl);
         return rpc_run_task(NFS_CLIENT(lsp->ls_state->inode), RPC_TASK_ASYNC, &nfs4_locku_ops, data);
 }
 
@@ -3270,30 +3265,28 @@ static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *
         struct rpc_task *task;
         int status = 0;
 
-        /* Is this a delegated lock? */
-        if (test_bit(NFS_DELEGATED_STATE, &state->flags))
-                goto out_unlock;
-        /* Is this open_owner holding any locks on the server? */
-        if (test_bit(LK_STATE_IN_USE, &state->flags) == 0)
-                goto out_unlock;
-
         status = nfs4_set_lock_state(state, request);
+        /* Unlock _before_ we do the RPC call */
+        request->fl_flags |= FL_EXISTS;
+        if (do_vfs_lock(request->fl_file, request) == -ENOENT)
+                goto out;
         if (status != 0)
-                goto out_unlock;
+                goto out;
+        /* Is this a delegated lock? */
+        if (test_bit(NFS_DELEGATED_STATE, &state->flags))
+                goto out;
         lsp = request->fl_u.nfs4_fl.owner;
-        status = -ENOMEM;
         seqid = nfs_alloc_seqid(&lsp->ls_seqid);
+        status = -ENOMEM;
         if (seqid == NULL)
-                goto out_unlock;
+                goto out;
         task = nfs4_do_unlck(request, request->fl_file->private_data, lsp, seqid);
         status = PTR_ERR(task);
         if (IS_ERR(task))
-                goto out_unlock;
+                goto out;
         status = nfs4_wait_for_completion_rpc_task(task);
         rpc_release_task(task);
-        return status;
-out_unlock:
-        do_vfs_lock(request->fl_file, request);
+out:
         return status;
 }