+/* Since the DIO code tries to lock a wide area we need to look for any ordered
+ * extents that exist in the range, rather than just the start of the range.
+ */
+struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
+ u64 file_offset,
+ u64 len)
+{
+ struct btrfs_ordered_inode_tree *tree;
+ struct rb_node *node;
+ struct btrfs_ordered_extent *entry = NULL;
+
+ tree = &BTRFS_I(inode)->ordered_tree;
+ spin_lock(&tree->lock);
+ node = tree_search(tree, file_offset);
+ if (!node) {
+ node = tree_search(tree, file_offset + len);
+ if (!node)
+ goto out;
+ }
+
+ while (1) {
+ entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+ if (range_overlaps(entry, file_offset, len))
+ break;
+
+ if (entry->file_offset >= file_offset + len) {
+ entry = NULL;
+ break;
+ }
+ entry = NULL;
+ node = rb_next(node);
+ if (!node)
+ break;
+ }
+out:
+ if (entry)
+ atomic_inc(&entry->refs);
+ spin_unlock(&tree->lock);
+ return entry;
+}
+