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: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/bmap.c

@@ -60,7 +60,7 @@ static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
 	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 @@ static int gfs2_block_truncate_page(struct address_space *mapping, loff_t from)
 	struct page *page;
 	int err;
 
-	page = grab_cache_page(mapping, index);
+	page = find_or_create_page(mapping, index, GFP_NOFS);
 	if (!page)
 		return 0;
 

fs/gfs2/quota.c

@@ -681,7 +681,7 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
 	ptr = qp;
 	nbytes = sizeof(struct gfs2_quota);
 get_a_page:
-	page = grab_cache_page(mapping, index);
+	page = find_or_create_page(mapping, index, GFP_NOFS);
 	if (!page)
 		return -ENOMEM;