New function insert_data_ranges() will insert non-overlap reserve ranges into reserve map.
It provides the basis for later qgroup reserve map implement. Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com> --- fs/btrfs/qgroup.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index fc24fc3..a4e3af4 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2577,6 +2577,130 @@ find_reserve_range(struct btrfs_qgroup_data_rsv_map *map, u64 start) } /* + * Insert one data range + * [start,len) here won't overflap with each other. + * + * Return 0 if range is inserted and tmp is not used. + * Return > 0 if range is inserted and tmp is used. + * No catchable error case. Only possible error will cause BUG_ON() as + * that's logical error. + */ +static int insert_data_range(struct btrfs_qgroup_data_rsv_map *map, + struct data_rsv_range *tmp, + u64 start, u64 len) +{ + struct rb_node **p = &map->root.rb_node; + struct rb_node *parent = NULL; + struct rb_node *tmp_node = NULL; + struct data_rsv_range *range = NULL; + struct data_rsv_range *prev_range = NULL; + struct data_rsv_range *next_range = NULL; + int prev_merged = 0; + int next_merged = 0; + int ret = 0; + + while (*p) { + parent = *p; + range = rb_entry(parent, struct data_rsv_range, node); + if (range->start < start) + p = &(*p)->rb_right; + else if (range->start > start) + p = &(*p)->rb_left; + else + BUG_ON(1); + } + + /* Empty tree, goto isolated case */ + if (!range) + goto insert_isolated; + + /* get adjusted ranges */ + if (range->start < start) { + prev_range = range; + tmp_node = rb_next(parent); + if (tmp) + next_range = rb_entry(tmp_node, struct data_rsv_range, + node); + } else { + next_range = range; + tmp_node = rb_prev(parent); + if (tmp) + prev_range = rb_entry(tmp_node, struct data_rsv_range, + node); + } + + /* try to merge with previous and next ranges */ + if (prev_range && prev_range->start + prev_range->len == start) { + prev_merged = 1; + prev_range->len += len; + } + if (next_range && start + len == next_range->start) { + next_merged = 1; + + /* + * the range can be merged with adjusted two ranges into one, + * remove the tailing range. + */ + if (prev_merged) { + prev_range->len += next_range->len; + rb_erase(&next_range->node, &map->root); + kfree(next_range); + } else { + next_range->start = start; + next_range->len += len; + } + } + +insert_isolated: + /* isolated case, need to insert range now */ + if (!next_merged && !prev_merged) { + BUG_ON(!tmp); + + tmp->start = start; + tmp->len = len; + rb_link_node(&tmp->node, parent, p); + rb_insert_color(&tmp->node, &map->root); + ret = 1; + } + return ret; +} + +/* + * insert reserve range and merge them if possible + * + * Return 0 if all inserted and tmp not used + * Return > 0 if all inserted and tmp used + * No catchable error return value. + */ +static int insert_data_ranges(struct btrfs_qgroup_data_rsv_map *map, + struct data_rsv_range *tmp, + struct ulist *insert_list) +{ + struct ulist_node *unode; + struct ulist_iterator uiter; + int tmp_used = 0; + int ret = 0; + + ULIST_ITER_INIT(&uiter); + while ((unode = ulist_next(insert_list, &uiter))) { + ret = insert_data_range(map, tmp, unode->val, unode->aux); + + /* + * insert_data_range() won't return error return value, + * no need to hanle <0 case. + * + * Also tmp should be used at most one time, so clear it to + * NULL to cooperate with sanity check in insert_data_range(). + */ + if (ret > 0) { + tmp_used = 1; + tmp = NULL; + } + } + return tmp_used; +} + +/* * Init data_rsv_map for a given inode. * * This is needed at write time as quota can be disabled and then enabled -- 2.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html