JFFS2: Return early when file read not necessary

If a destination is not provided, jffs2_1pass_read_inode() only
returns the length of the file. In this case, avoid reading all
the data nodes, and return as soon as the length of the file is
known.

Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
diff --git a/fs/jffs2/jffs2_1pass.c b/fs/jffs2/jffs2_1pass.c
index b1d6470..2e569ff 100644
--- a/fs/jffs2/jffs2_1pass.c
+++ b/fs/jffs2/jffs2_1pass.c
@@ -719,6 +719,12 @@
 		}
 		put_fl_mem(jNode, pL->readbuf);
 	}
+	/*
+	 * If no destination is provided, we are done.
+	 * Just return the total size.
+	 */
+	if (!dest)
+		return totalSize;
 #endif
 
 	for (b = pL->frag.listHead; b != NULL; b = b->next) {