gfs2: jdata writepage fix

The ->writepage() and ->writepages() operations are supposed to write
entire pages.  However, on filesystems with a block size smaller than
PAGE_SIZE, __gfs2_jdata_writepage() only adds the first block to the
current transaction instead of adding the entire page.  Fix that.

Fixes: 18ec7d5c ("[GFS2] Make journaled data files identical to normal files on disk")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/aops.c

@@ -127,7 +127,6 @@ static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *w
 {
 	struct inode *inode = page->mapping->host;
 	struct gfs2_inode *ip = GFS2_I(inode);
-	struct gfs2_sbd *sdp = GFS2_SB(inode);
 
 	if (PageChecked(page)) {
 		ClearPageChecked(page);
@@ -135,7 +134,7 @@ static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *w
 			create_empty_buffers(page, inode->i_sb->s_blocksize,
 					     BIT(BH_Dirty)|BIT(BH_Uptodate));
 		}
-		gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize);
+		gfs2_page_add_databufs(ip, page, 0, PAGE_SIZE);
 	}
 	return gfs2_write_jdata_page(page, wbc);
 }