btrfs: don't use set/get token in leaf_space_used (a31356b9) · Commits · 戴 / test

The token is supposed to cache the last page used by the set/get helpers. In leaf_space_used the first and last items are accessed, it's not likely they'd be on the same page so there's some overhead caused updating the token address but not using it. Reviewed-by:

Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by:

David Sterba <dsterba@suse.com>

fs/btrfs/ctree.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -3507,19 +3507,17 @@ static int leaf_space_used(struct extent_buffer *l, int start, int nr)
		{
		struct btrfs_item *start_item;
		struct btrfs_item *end_item;
		struct btrfs_map_token token;
		int data_len;
		int nritems = btrfs_header_nritems(l);
		int end = min(nritems, start + nr) - 1;

		if (!nr)
		return 0;
		btrfs_init_map_token(&token, l);
		start_item = btrfs_item_nr(start);
		end_item = btrfs_item_nr(end);
		data_len = btrfs_token_item_offset(&token, start_item) +
		btrfs_token_item_size(&token, start_item);
		data_len = data_len - btrfs_token_item_offset(&token, end_item);
		data_len = btrfs_item_offset(l, start_item) +
		btrfs_item_size(l, start_item);
		data_len = data_len - btrfs_item_offset(l, end_item);
		data_len += sizeof(struct btrfs_item) * nr;
		WARN_ON(data_len < 0);
		return data_len;

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