+ io_tree = &BTRFS_I(inode)->io_tree;
+
+ lock_extent_bits(io_tree, lockstart, lockend, 0, &cached_state);
+ ordered = btrfs_lookup_ordered_range(inode, lockstart, len);
+ if (ordered) {
+ btrfs_put_ordered_extent(ordered);
+ goto out_unlock;
+ }
+
+ em = btrfs_get_extent(inode, NULL, 0, lockstart, len, 0);
+ if (IS_ERR(em)) {
+ ret = PTR_ERR(em);
+ goto out_unlock;
+ }
+
+ /*
+ * This extent does not actually cover the logical extent anymore,
+ * move on to the next inode.
+ */
+ if (em->block_start > nocow_ctx->logical ||
+ em->block_start + em->block_len < nocow_ctx->logical + len) {
+ free_extent_map(em);
+ goto out_unlock;
+ }
+ free_extent_map(em);
+