On 2019/8/6 8:13 下午, Shenghui Wang wrote:
> commit 2a285686c1098 ("bcache: btree locking rework") introduced
> bch_btree_init_next(), and moved the sort logic into the function.
> Before the commit introduced, __bch_btree_node_write() will do sort
> first, then do possible verify. After the change, the verify will
> run before any sort/change sets of btree node, and no verify will
> run after sort done in bch_btree_init_next().
>
> Move the verify code into bch_btree_init_next(), right after sort done.
>
Hi Shenghui,
What is the benefit of this change ?
Thanks.
Coly Li
> Signed-off-by: Shenghui Wang <shhuiw@xxxxxxxxxxx>
> ---
> drivers/md/bcache/btree.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
> index ba434d9ac720..b15878334a29 100644
> --- a/drivers/md/bcache/btree.c
> +++ b/drivers/md/bcache/btree.c
> @@ -167,16 +167,24 @@ static inline struct bset *write_block(struct btree *b)
>
> static void bch_btree_init_next(struct btree *b)
> {
> + unsigned int nsets = b->keys.nsets;
> +
> /* If not a leaf node, always sort */
> if (b->level && b->keys.nsets)
> bch_btree_sort(&b->keys, &b->c->sort);
> else
> bch_btree_sort_lazy(&b->keys, &b->c->sort);
>
> + /*
> + * do verify if there was more than one set initially (i.e. we did a
> + * sort) and we sorted down to a single set:
> + */
> + if (nsets && !b->keys.nsets)
> + bch_btree_verify(b);
> +
> if (b->written < btree_blocks(b))
> bch_bset_init_next(&b->keys, write_block(b),
> bset_magic(&b->c->sb));
> -
> }
>
> /* Btree key manipulation */
> @@ -489,19 +497,9 @@ void __bch_btree_node_write(struct btree *b, struct closure *parent)
>
> void bch_btree_node_write(struct btree *b, struct closure *parent)
> {
> - unsigned int nsets = b->keys.nsets;
> -
> lockdep_assert_held(&b->lock);
>
> __bch_btree_node_write(b, parent);
> -
> - /*
> - * do verify if there was more than one set initially (i.e. we did a
> - * sort) and we sorted down to a single set:
> - */
> - if (nsets && !b->keys.nsets)
> - bch_btree_verify(b);
> -
> bch_btree_init_next(b);
> }
>
>
--
Coly Li
