Re: [PATCH 03/10] btrfs-progs: port block group cache tree insertion and lookup functions

Qu Wenruo
2019-12-05T07:30:07Z

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On 2019/12/5 下午12:29, damenly.su@gmail.com wrote:
> From: Su Yue <Damenly_Su@gmx.com>
>
> Simple copy and paste codes, remove useless lock operantions in progs.
> Th new coming lookup functions are named with suffix _kernel in
> temporary.
>
> Signed-off-by: Su Yue <Damenly_Su@gmx.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Just an extra hint, it would be much better if we backport this
functions to block-group.c.

Thanks,
Qu
> ---
> extent-tree.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 86 insertions(+)
>
> diff --git a/extent-tree.c b/extent-tree.c
> index 4a3db029e811..ab576f8732a2 100644
> --- a/extent-tree.c
> +++ b/extent-tree.c
> @@ -164,6 +164,92 @@ err:
> return 0;
> }
>
> +/*
> + * This adds the block group to the fs_info rb tree for the block group cache
> + */
> +static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
> + struct btrfs_block_group_cache *block_group)
> +{
> + struct rb_node **p;
> + struct rb_node *parent = NULL;
> + struct btrfs_block_group_cache *cache;
> +
> + p = &info->block_group_cache_tree.rb_node;
> +
> + while (*p) {
> + parent = *p;
> + cache = rb_entry(parent, struct btrfs_block_group_cache,
> + cache_node);
> + if (block_group->key.objectid < cache->key.objectid)
> + p = &(*p)->rb_left;
> + else if (block_group->key.objectid > cache->key.objectid)
> + p = &(*p)->rb_right;
> + else
> + return -EEXIST;
> + }
> +
> + rb_link_node(&block_group->cache_node, parent, p);
> + rb_insert_color(&block_group->cache_node,
> + &info->block_group_cache_tree);
> +
> + return 0;
> +}
> +
> +/*
> + * This will return the block group at or after bytenr if contains is 0, else
> + * it will return the block group that contains the bytenr
> + */
> +static struct btrfs_block_group_cache *block_group_cache_tree_search(
> + struct btrfs_fs_info *info, u64 bytenr, int contains)
> +{
> + struct btrfs_block_group_cache *cache, *ret = NULL;
> + struct rb_node *n;
> + u64 end, start;
> +
> + n = info->block_group_cache_tree.rb_node;
> +
> + while (n) {
> + cache = rb_entry(n, struct btrfs_block_group_cache,
> + cache_node);
> + end = cache->key.objectid + cache->key.offset - 1;
> + start = cache->key.objectid;
> +
> + if (bytenr < start) {
> + if (!contains && (!ret || start < ret->key.objectid))
> + ret = cache;
> + n = n->rb_left;
> + } else if (bytenr > start) {
> + if (contains && bytenr <= end) {
> + ret = cache;
> + break;
> + }
> + n = n->rb_right;
> + } else {
> + ret = cache;
> + break;
> + }
> + }
> + return ret;
> +}
> +
> +/*
> + * Return the block group that starts at or after bytenr
> + */
> +struct btrfs_block_group_cache *btrfs_lookup_first_block_group_kernel(
> + struct btrfs_fs_info *info, u64 bytenr)
> +{
> + return block_group_cache_tree_search(info, bytenr, 0);
> +}
> +
> +/*
> + * Return the block group that contains the given bytenr
> + */
> +struct btrfs_block_group_cache *btrfs_lookup_block_group_kernel(
> + struct btrfs_fs_info *info, u64 bytenr)
> +{
> + return block_group_cache_tree_search(info, bytenr, 1);
> +}
> +
> /*
> * Return the block group that contains @bytenr, otherwise return the next one
> * that starts after @bytenr
>

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