Re: [PATCH v2 07/11] fs/ext4: use rbtree postorder iteration helperinstead of opencoding

From: Jan Kara
Date: Thu Nov 07 2013 - 04:28:11 EST


On Wed 06-11-13 17:42:36, Cody P Schafer wrote:
> Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
> of opencoding an alternate postorder iteration that modifies the tree
The patch looks good. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

>
> Signed-off-by: Cody P Schafer <cody@xxxxxxxxxxxxxxxxxx>
> ---
> fs/ext4/block_validity.c | 33 ++++-----------------------------
> fs/ext4/dir.c | 35 +++++------------------------------
> 2 files changed, 9 insertions(+), 59 deletions(-)
>
> diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
> index 3f11656..41eb9dc 100644
> --- a/fs/ext4/block_validity.c
> +++ b/fs/ext4/block_validity.c
> @@ -180,37 +180,12 @@ int ext4_setup_system_zone(struct super_block *sb)
> /* Called when the filesystem is unmounted */
> void ext4_release_system_zone(struct super_block *sb)
> {
> - struct rb_node *n = EXT4_SB(sb)->system_blks.rb_node;
> - struct rb_node *parent;
> - struct ext4_system_zone *entry;
> + struct ext4_system_zone *entry, *n;
>
> - while (n) {
> - /* Do the node's children first */
> - if (n->rb_left) {
> - n = n->rb_left;
> - continue;
> - }
> - if (n->rb_right) {
> - n = n->rb_right;
> - continue;
> - }
> - /*
> - * The node has no children; free it, and then zero
> - * out parent's link to it. Finally go to the
> - * beginning of the loop and try to free the parent
> - * node.
> - */
> - parent = rb_parent(n);
> - entry = rb_entry(n, struct ext4_system_zone, node);
> + rbtree_postorder_for_each_entry_safe(entry, n,
> + &EXT4_SB(sb)->system_blks, node)
> kmem_cache_free(ext4_system_zone_cachep, entry);
> - if (!parent)
> - EXT4_SB(sb)->system_blks = RB_ROOT;
> - else if (parent->rb_left == n)
> - parent->rb_left = NULL;
> - else if (parent->rb_right == n)
> - parent->rb_right = NULL;
> - n = parent;
> - }
> +
> EXT4_SB(sb)->system_blks = RB_ROOT;
> }
>
> diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
> index 680bb33..d638c57 100644
> --- a/fs/ext4/dir.c
> +++ b/fs/ext4/dir.c
> @@ -353,41 +353,16 @@ struct fname {
> */
> static void free_rb_tree_fname(struct rb_root *root)
> {
> - struct rb_node *n = root->rb_node;
> - struct rb_node *parent;
> - struct fname *fname;
> -
> - while (n) {
> - /* Do the node's children first */
> - if (n->rb_left) {
> - n = n->rb_left;
> - continue;
> - }
> - if (n->rb_right) {
> - n = n->rb_right;
> - continue;
> - }
> - /*
> - * The node has no children; free it, and then zero
> - * out parent's link to it. Finally go to the
> - * beginning of the loop and try to free the parent
> - * node.
> - */
> - parent = rb_parent(n);
> - fname = rb_entry(n, struct fname, rb_hash);
> + struct fname *fname, *next;
> +
> + rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
> while (fname) {
> struct fname *old = fname;
> fname = fname->next;
> kfree(old);
> }
> - if (!parent)
> - *root = RB_ROOT;
> - else if (parent->rb_left == n)
> - parent->rb_left = NULL;
> - else if (parent->rb_right == n)
> - parent->rb_right = NULL;
> - n = parent;
> - }
> +
> + *root = RB_ROOT;
> }
>
>
> --
> 1.8.4.2
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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