ocfs2: correctly check the return value of ocfs2_search_extent_list

ocfs2_search_extent_list may return -1, so we should check the return
value in ocfs2_split_and_insert, otherwise it may cause array index out of
bound.

And ocfs2_search_extent_list can only return value less than
el->l_next_free_rec, so check if it is equal or larger than
le16_to_cpu(el->l_next_free_rec) is meaningless.

Signed-off-by: Yingtai Xie <xieyingtai@huawei.com>
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/alloc.c

@@ -4961,6 +4961,15 @@ leftright:
 
 		el = path_leaf_el(path);
 		split_index = ocfs2_search_extent_list(el, cpos);
+		if (split_index == -1) {
+			ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
+					"Owner %llu has an extent at cpos %u "
+					"which can no longer be found.\n",
+					(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
+					cpos);
+			ret = -EROFS;
+			goto out;
+		}
 		goto leftright;
 	}
 out:
@@ -5135,7 +5144,7 @@ int ocfs2_change_extent_flag(handle_t *handle,
 	el = path_leaf_el(left_path);
 
 	index = ocfs2_search_extent_list(el, cpos);
-	if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+	if (index == -1) {
 		ocfs2_error(sb,
 			    "Owner %llu has an extent at cpos %u which can no "
 			    "longer be found.\n",
@@ -5491,7 +5500,7 @@ int ocfs2_remove_extent(handle_t *handle,
 
 	el = path_leaf_el(path);
 	index = ocfs2_search_extent_list(el, cpos);
-	if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+	if (index == -1) {
 		ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
 			    "Owner %llu has an extent at cpos %u which can no "
 			    "longer be found.\n",
@@ -5557,7 +5566,7 @@ int ocfs2_remove_extent(handle_t *handle,
 
 		el = path_leaf_el(path);
 		index = ocfs2_search_extent_list(el, cpos);
-		if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+		if (index == -1) {
 			ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
 				    "Owner %llu: split at cpos %u lost record.",
 				    (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),

fs/ocfs2/move_extents.c

@@ -98,7 +98,7 @@ static int __ocfs2_move_extent(handle_t *handle,
 	el = path_leaf_el(path);
 
 	index = ocfs2_search_extent_list(el, cpos);
-	if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+	if (index == -1) {
 		ocfs2_error(inode->i_sb,
 			    "Inode %llu has an extent at cpos %u which can no "
 			    "longer be found.\n",

fs/ocfs2/refcounttree.c

@@ -3109,7 +3109,7 @@ static int ocfs2_clear_ext_refcount(handle_t *handle,
 	el = path_leaf_el(path);
 
 	index = ocfs2_search_extent_list(el, cpos);
-	if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+	if (index == -1) {
 		ocfs2_error(sb,
 			    "Inode %llu has an extent at cpos %u which can no "
 			    "longer be found.\n",