On 5.09.2018 09:29, Qu Wenruo wrote:
> Introduce a new function, btrfs_next_sibling_tree_block(), which could
> find any sibling tree blocks at path->lowest_level, unlike level 0
> limited btrfs_next_leaf().
>
> Since this function is more generic than btrfs_next_leaf(), also make
> btrfs_next_leaf() a wrapper of btrfs_next_sibling_tree_block(), to keep
> the interface the same as kernel.
>
> This would provide the basis for later breadth-first search print-tree.
>
> Signed-off-by: Qu Wenruo <w...@suse.com>
Reviewed-by: Nikolay Borisov <nbori...@suse.com>
> ---
> ctree.c | 14 +++++++++-----
> ctree.h | 15 ++++++++++++++-
> 2 files changed, 23 insertions(+), 6 deletions(-)
>
> diff --git a/ctree.c b/ctree.c
> index 042fae19344d..43d47f19c9cd 100644
> --- a/ctree.c
> +++ b/ctree.c
> @@ -2875,18 +2875,22 @@ int btrfs_prev_leaf(struct btrfs_root *root, struct
> btrfs_path *path)
> }
>
> /*
> - * walk up the tree as far as required to find the next leaf.
> + * walk up the tree as far as required to find the next sibling tree block.
> + * more generic version of btrfs_next_leaf(), as it could find sibling nodes
> + * if @path->lowest_level is not 0.
> + *
> * returns 0 if it found something or 1 if there are no greater leaves.
> * returns < 0 on io errors.
> */
> -int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
> +int btrfs_next_sibling_tree_block(struct btrfs_fs_info *fs_info,
> + struct btrfs_path *path)
> {
> int slot;
> - int level = 1;
> + int level = path->lowest_level + 1;
> struct extent_buffer *c;
> struct extent_buffer *next = NULL;
> - struct btrfs_fs_info *fs_info = root->fs_info;
>
> + BUG_ON(path->lowest_level + 1 >= BTRFS_MAX_LEVEL);
> while(level < BTRFS_MAX_LEVEL) {
> if (!path->nodes[level])
> return 1;
> @@ -2915,7 +2919,7 @@ int btrfs_next_leaf(struct btrfs_root *root, struct
> btrfs_path *path)
> free_extent_buffer(c);
> path->nodes[level] = next;
> path->slots[level] = 0;
> - if (!level)
> + if (level == path->lowest_level)
> break;
> if (path->reada)
> reada_for_search(fs_info, path, level, 0, 0);
> diff --git a/ctree.h b/ctree.h
> index 6df6075865c2..939c584d0301 100644
> --- a/ctree.h
> +++ b/ctree.h
> @@ -2633,7 +2633,20 @@ static inline int btrfs_insert_empty_item(struct
> btrfs_trans_handle *trans,
> return btrfs_insert_empty_items(trans, root, path, key, &data_size, 1);
> }
>
> -int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
> +int btrfs_next_sibling_tree_block(struct btrfs_fs_info *fs_info,
> + struct btrfs_path *path);
> +/*
> + * walk up the tree as far as required to find the next leaf.
> + * returns 0 if it found something or 1 if there are no greater leaves.
> + * returns < 0 on io errors.
> + */
> +static inline int btrfs_next_leaf(struct btrfs_root *root,
> + struct btrfs_path *path)
> +{
> + path->lowest_level = 0;
> + return btrfs_next_sibling_tree_block(root->fs_info, path);
> +}
> +
> static inline int btrfs_next_item(struct btrfs_root *root,
> struct btrfs_path *p)
> {
>
