GFS2: Change truncate page allocation to be GFP_NOFS

This patch changes the page allocation in gfs2_block_truncate_page
and two others to GFP_NOFS to avoid deadlock in low-memory conditions.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 14a7040..197c5c4 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -60,7 +60,7 @@
 	int release = 0;
 
 	if (!page || page->index) {
-		page = grab_cache_page(inode->i_mapping, 0);
+		page = find_or_create_page(inode->i_mapping, 0, GFP_NOFS);
 		if (!page)
 			return -ENOMEM;
 		release = 1;
@@ -930,7 +930,7 @@
 	struct page *page;
 	int err;
 
-	page = grab_cache_page(mapping, index);
+	page = find_or_create_page(mapping, index, GFP_NOFS);
 	if (!page)
 		return 0;