Commit 58147d5a authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: don't do extra find_extent_buffer() in do_walk_down() 



We do find_extent_buffer(), and then if we don't find the eb in cache we
call btrfs_find_create_tree_block(), which calls find_extent_buffer()
first and then allocates the extent buffer.

The reason we're doing this is because if we don't find the extent
buffer in cache we set reada = 1.  However this doesn't matter, because
lower down we only trigger reada if !btrfs_buffer_uptodate(eb), which is
what the case would be if we didn't find the extent buffer in cache and
had to allocate it.

Clean this up to simply call btrfs_find_create_tree_block(), and then
use the fact that we're having to read the extent buffer off of disk to
go ahead and kick off readahead.

Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 45c4102f

fs/btrfs/extent-tree.c

+6 −10
Original line number Diff line number Diff line
@@ -5433,7 +5433,6 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans, 
	struct btrfs_key key;

	struct extent_buffer *next;

	int level = wc->level;

	int reada = 0;

	int ret = 0;

	bool need_account = false;
@@ -5459,14 +5458,11 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans, 
	btrfs_node_key_to_cpu(path->nodes[level], &check.first_key,

			      path->slots[level]);



	next = find_extent_buffer(fs_info, bytenr);

	if (!next) {

		next = btrfs_find_create_tree_block(fs_info, bytenr,

				btrfs_root_id(root), level - 1);

	next = btrfs_find_create_tree_block(fs_info, bytenr, btrfs_root_id(root),

					    level - 1);

	if (IS_ERR(next))

		return PTR_ERR(next);

		reada = 1;

	}



	btrfs_tree_lock(next);



	ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
@@ -5517,7 +5513,7 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans, 
	}



	if (!next) {

		if (reada && level == 1)

		if (level == 1)

			reada_walk_down(trans, root, wc, path);

		next = read_tree_block(fs_info, bytenr, &check);

		if (IS_ERR(next)) {