On Fri 08-02-13 16:43:57, Zheng Liu wrote:
> From: Zheng Liu <wenqing.lz@xxxxxxxxxx>
>
> This commit refines the extent status tree code.
>
> 1) A prefix 'es_' is added to to the extent status tree structure
> members.
>
> 2) Refactored es_remove_extent() so that __es_remove_extent() can be
> used by es_insert_extent() to remove the old extent entry(-ies) before
> inserting a new one.
>
> 3) Rename extent_status_end() to ext4_es_end()
>
> 4) ext4_es_can_be_merged() is define to check whether two extents can
> be merged or not.
>
> 5) Update and clarified comments.
Just one minor comment below. Otherwise the patch looks good (although I
admit I didn't check all the renaming changes carefully. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
>
> Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
> Cc: "Theodore Ts'o" <tytso@xxxxxxx>
> Cc: Jan kara <jack@xxxxxxx>
> ---
> fs/ext4/extents.c | 21 +--
> fs/ext4/extents_status.c | 318 ++++++++++++++++++++++++--------------------
> fs/ext4/extents_status.h | 8 +-
> fs/ext4/file.c | 12 +-
> include/trace/events/ext4.h | 40 +++---
> 5 files changed, 217 insertions(+), 182 deletions(-)
>
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
...
> @@ -320,60 +352,39 @@ ext4_es_try_to_merge_right(struct ext4_es_tree *tree, struct extent_status *es)
> return es;
> }
>
> -static int __es_insert_extent(struct ext4_es_tree *tree, ext4_lblk_t offset,
> - ext4_lblk_t len)
> +static int __es_insert_extent(struct ext4_es_tree *tree,
> + struct extent_status *newes)
> {
> struct rb_node **p = &tree->root.rb_node;
> struct rb_node *parent = NULL;
> struct extent_status *es;
> - ext4_lblk_t end = offset + len - 1;
> -
> - BUG_ON(end < offset);
> - es = tree->cache_es;
> - if (es && offset == (extent_status_end(es) + 1)) {
> - es_debug("cached by [%u/%u)\n", es->start, es->len);
> - es->len += len;
> - es = ext4_es_try_to_merge_right(tree, es);
> - goto out;
> - } else if (es && es->start == end + 1) {
> - es_debug("cached by [%u/%u)\n", es->start, es->len);
> - es->start = offset;
> - es->len += len;
> - es = ext4_es_try_to_merge_left(tree, es);
> - goto out;
> - } else if (es && es->start <= offset &&
> - end <= extent_status_end(es)) {
> - es_debug("cached by [%u/%u)\n", es->start, es->len);
> - goto out;
> - }
>
> while (*p) {
> parent = *p;
> es = rb_entry(parent, struct extent_status, rb_node);
>
> - if (offset < es->start) {
> - if (es->start == end + 1) {
> - es->start = offset;
> - es->len += len;
> + if (newes->es_lblk < es->es_lblk) {
> + if (ext4_es_can_be_merged(newes, es)) {
> + es->es_lblk = newes->es_lblk;
> + es->es_len += newes->es_len;
This is wrong, isn't it? You cannot change es->es_lblk because that can
break ordering of elements in the tree... thinking ... ah, it's OK because
you have non-overlapping intervals. But it deserves a comment I guess.
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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