NLM,NFSv4: Wait on local locks before we put RPC calls on the wire

Use FL_ACCESS flag to test and/or wait for local locks before we try
requesting a lock from the server

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

1 files changed, 24 insertions, 11 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 8bdfe3ff7925..e6ee97f19d81 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3489,29 +3489,42 @@ static int nfs4_lock_expired(struct nfs4_state *state, struct file_lock *request
 static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
 {
         struct nfs4_client *clp = state->owner->so_client;
+        unsigned char fl_flags = request->fl_flags;
         int status;
 
         /* Is this a delegated open? */
-        if (NFS_I(state->inode)->delegation_state != 0) {
-                /* Yes: cache locks! */
-                status = do_vfs_lock(request->fl_file, request);
-                /* ...but avoid races with delegation recall... */
-                if (status < 0 || test_bit(NFS_DELEGATED_STATE, &state->flags))
-                        return status;
-        }
-        down_read(&clp->cl_sem);
         status = nfs4_set_lock_state(state, request);
         if (status != 0)
                 goto out;
+        request->fl_flags |= FL_ACCESS;
+        status = do_vfs_lock(request->fl_file, request);
+        if (status < 0)
+                goto out;
+        down_read(&clp->cl_sem);
+        if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
+                struct nfs_inode *nfsi = NFS_I(state->inode);
+                /* Yes: cache locks! */
+                down_read(&nfsi->rwsem);
+                /* ...but avoid races with delegation recall... */
+                if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
+                        request->fl_flags = fl_flags & ~FL_SLEEP;
+                        status = do_vfs_lock(request->fl_file, request);
+                        up_read(&nfsi->rwsem);
+                        goto out_unlock;
+                }
+                up_read(&nfsi->rwsem);
+        }
         status = _nfs4_do_setlk(state, cmd, request, 0);
         if (status != 0)
-                goto out;
+                goto out_unlock;
         /* Note: we always want to sleep here! */
-        request->fl_flags |= FL_SLEEP;
+        request->fl_flags = fl_flags | FL_SLEEP;
         if (do_vfs_lock(request->fl_file, request) < 0)
                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
-out:
+out_unlock:
         up_read(&clp->cl_sem);
+out:
+        request->fl_flags = fl_flags;
         return status;
 }