NFS: do_setlk(): don't flush caches when we have a delegation

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 7ac89a8..0213c21 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -602,7 +602,8 @@
 	 * This makes locking act as a cache coherency point.
 	 */
 	nfs_sync_mapping(filp->f_mapping);
-	nfs_zap_caches(inode);
+	if (!nfs_have_delegation(inode, FMODE_READ))
+		nfs_zap_caches(inode);
 out:
 	return status;
 }