-/* Find next extent map of a given extent map, caller needs to ensure locks */
-static struct extent_map *next_extent_map(struct extent_map *em)
-{
- struct rb_node *next;
-
- next = rb_next(&em->rb_node);
- if (!next)
- return NULL;
- return container_of(next, struct extent_map, rb_node);
-}
-
-static struct extent_map *prev_extent_map(struct extent_map *em)
-{
- struct rb_node *prev;
-
- prev = rb_prev(&em->rb_node);
- if (!prev)
- return NULL;
- return container_of(prev, struct extent_map, rb_node);
-}
-
-/* helper for btfs_get_extent. Given an existing extent in the tree,
- * the existing extent is the nearest extent to map_start,
- * and an extent that you want to insert, deal with overlap and insert
- * the best fitted new extent into the tree.
- */
-static int merge_extent_mapping(struct extent_map_tree *em_tree,
- struct extent_map *existing,
- struct extent_map *em,
- u64 map_start)
-{
- struct extent_map *prev;
- struct extent_map *next;
- u64 start;
- u64 end;
- u64 start_diff;
-
- BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
-
- if (existing->start > map_start) {
- next = existing;
- prev = prev_extent_map(next);
- } else {
- prev = existing;
- next = next_extent_map(prev);
- }
-
- start = prev ? extent_map_end(prev) : em->start;
- start = max_t(u64, start, em->start);
- end = next ? next->start : extent_map_end(em);
- end = min_t(u64, end, extent_map_end(em));
- start_diff = start - em->start;
- em->start = start;
- em->len = end - start;
- if (em->block_start < EXTENT_MAP_LAST_BYTE &&
- !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
- em->block_start += start_diff;
- em->block_len -= start_diff;
- }
- return add_extent_mapping(em_tree, em, 0);
-}
-