nfsd: Fix a memory leak of struct file_lock

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 61dfb33..84fb6eb 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3934,6 +3934,7 @@
 	if (!filp) {
 		/* We should always have a readable file here */
 		WARN_ON_ONCE(1);
+		locks_free_lock(fl);
 		return -EBADF;
 	}
 	fl->fl_file = filp;