staging: lustre: llite: check ret of ll_prep_md_op_data in ll_dir_filler

ll_dir_filler() now checks the returned pointer from
ll_prep_md_op_data() using IS_ERR()
Signed-off-by: Swapnil Pimpale <spimpale@ddn.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4082
Reviewed-on: http://review.whamcloud.com/8073Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/dir.c

@@ -163,6 +163,11 @@ static int ll_dir_filler(void *_hash, struct page *page0)
 
 	LASSERT(max_pages > 0 && max_pages <= MD_MAX_BRW_PAGES);
 
+	op_data = ll_prep_md_op_data(NULL, inode, NULL, NULL, 0, 0,
+				     LUSTRE_OPC_ANY, NULL);
+	if (IS_ERR(op_data))
+		return PTR_ERR(op_data);
+
 	page_pool = kcalloc(max_pages, sizeof(page), GFP_NOFS);
 	if (page_pool) {
 		page_pool[0] = page0;
@@ -177,8 +182,6 @@ static int ll_dir_filler(void *_hash, struct page *page0)
 		page_pool[npages] = page;
 	}
 
-	op_data = ll_prep_md_op_data(NULL, inode, NULL, NULL, 0, 0,
-				     LUSTRE_OPC_ANY, NULL);
 	op_data->op_npages = npages;
 	op_data->op_offset = hash;
 	rc = md_readpage(exp, op_data, page_pool, &request);