staging/lustre/llite: make sure we do cl_page_clip on the last page

When we are doing a partial IO on both first and last page,
the logic currently only call cl_page_clip on the first page, which
will end up with a incorrect i_size.
Signed-off-by: Li Dongyang <dongyang.li@anu.edu.au>
Reviewed-on: http://review.whamcloud.com/11630
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5552Reviewed-by: Ian Costello <costello.ian@gmail.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Li Xi <pkuelelixi@gmail.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/vvp_io.c

@@ -599,12 +599,14 @@ static int vvp_io_commit_sync(const struct lu_env *env, struct cl_io *io,
 		page = cl_page_list_first(plist);
 		if (plist->pl_nr == 1) {
 			cl_page_clip(env, page, from, to);
-		} else if (from > 0) {
-			cl_page_clip(env, page, from, PAGE_SIZE);
 		} else {
-		page = cl_page_list_last(plist);
-		cl_page_clip(env, page, 0, to);
-	}
+			if (from > 0)
+				cl_page_clip(env, page, from, PAGE_SIZE);
+			if (to != PAGE_SIZE) {
+				page = cl_page_list_last(plist);
+				cl_page_clip(env, page, 0, to);
+			}
+		}
 	}
 
 	cl_2queue_init(queue);