On 21.09.2018 10:20, Qu Wenruo wrote:
> And add one line comment explaining what we're doing for each loop.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
> ---
Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
> changelog:
> v2:
> Use rbtree_postorder_for_each_entry_safe() to replace for() loop.
> ---
> fs/btrfs/relocation.c | 24 +++++++++---------------
> 1 file changed, 9 insertions(+), 15 deletions(-)
>
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 8783a1776540..94aa148ccde6 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -2987,7 +2987,7 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans,
> struct backref_node *node;
> struct btrfs_path *path;
> struct tree_block *block;
> - struct rb_node *rb_node;
> + struct tree_block *next;
> int ret;
> int err = 0;
>
> @@ -2997,29 +2997,23 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans,
> goto out_free_blocks;
> }
>
> - rb_node = rb_first(blocks);
> - while (rb_node) {
> - block = rb_entry(rb_node, struct tree_block, rb_node);
> + /* Kick in readahead for tree blocks with missing keys */
> + rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
> if (!block->key_ready)
> readahead_tree_block(fs_info, block->bytenr);
> - rb_node = rb_next(rb_node);
> }
>
> - rb_node = rb_first(blocks);
> - while (rb_node) {
> - block = rb_entry(rb_node, struct tree_block, rb_node);
> + /* Get first keys */
> + rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
> if (!block->key_ready) {
> err = get_tree_block_key(fs_info, block);
> if (err)
> goto out_free_path;
> }
> - rb_node = rb_next(rb_node);
> }
>
> - rb_node = rb_first(blocks);
> - while (rb_node) {
> - block = rb_entry(rb_node, struct tree_block, rb_node);
> -
> + /* Do tree relocation */
> + rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
> node = build_backref_tree(rc, &block->key,
> block->level, block->bytenr);
> if (IS_ERR(node)) {
> @@ -3030,11 +3024,11 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans,
> ret = relocate_tree_block(trans, rc, node, &block->key,
> path);
> if (ret < 0) {
> - if (ret != -EAGAIN || rb_node == rb_first(blocks))
> + if (ret != -EAGAIN || &block->rb_node ==
> + rb_first(blocks))
> err = ret;
> goto out;
> }
> - rb_node = rb_next(rb_node);
> }
> out:
> err = finish_pending_nodes(trans, rc, path, err);
>
