ksmbd: fix infinite loop when client send search patten

MacOS send search patten in smb2 query_dir. If there is no file that
matched with search patten, d_info.num_entry is zero. This causes it
to retry iterate_dir(), which leads to an infinite loop.

Signed-off-by: Namjae Jeon <[email protected]>

smb2pdu.c

@@ -4664,6 +4664,7 @@ int smb2_query_dir(struct ksmbd_work *work)
 	set_ctx_actor(&dir_fp->readdir_data.ctx, __query_dir);
 
 again:
+	d_info.num_scan = 0;
 	rc = iterate_dir(dir_fp->filp, &dir_fp->readdir_data.ctx);
 	/*
 	 * num_entry can be 0 if the directory iteration stops before reaching