31.10.2018 14:34, Anton Nefedov wrote:
> This adds some protection from accounting unitialized cookie.
uninitialized
> That is, block_acct_failed/done without previous block_acct_start;
> in that case, cookie probably holds values from previous operation.
>
> (Note: it might also be unitialized holding garbage value and there is
and here.
> still "< BLOCK_MAX_IOTYPE" assertion for that.
> So block_acct_failed/done without previous block_acct_start should be used
> with caution.)
>
> Currently this is particularly useful in ide code where it's hard to
> keep track whether the request started accounting or not. For example,
> trim requests do the accounting separately.
so, is it an existing bug? Could you please give an example in the code of such
wrong (before the patch) accounting?
>
> Signed-off-by: Anton Nefedov <anton.nefe...@virtuozzo.com>
> ---
> include/block/accounting.h | 1 +
> block/accounting.c | 6 ++++++
> 2 files changed, 7 insertions(+)
>
> diff --git a/include/block/accounting.h b/include/block/accounting.h
> index ba8b04d572..878b4c3581 100644
> --- a/include/block/accounting.h
> +++ b/include/block/accounting.h
> @@ -33,6 +33,7 @@ typedef struct BlockAcctTimedStats BlockAcctTimedStats;
> typedef struct BlockAcctStats BlockAcctStats;
>
> enum BlockAcctType {
> + BLOCK_ACCT_NONE = 0,
> BLOCK_ACCT_READ,
> BLOCK_ACCT_WRITE,
> BLOCK_ACCT_FLUSH,
> diff --git a/block/accounting.c b/block/accounting.c
> index 70a3d9a426..8d41c8a83a 100644
> --- a/block/accounting.c
> +++ b/block/accounting.c
> @@ -195,6 +195,10 @@ static void block_account_one_io(BlockAcctStats *stats,
> BlockAcctCookie *cookie,
>
> assert(cookie->type < BLOCK_MAX_IOTYPE);
>
> + if (cookie->type == BLOCK_ACCT_NONE) {
> + return;
> + }
> +
> qemu_mutex_lock(&stats->lock);
>
> if (failed) {
> @@ -217,6 +221,8 @@ static void block_account_one_io(BlockAcctStats *stats,
> BlockAcctCookie *cookie,
> }
>
> qemu_mutex_unlock(&stats->lock);
> +
> + cookie->type = BLOCK_ACCT_NONE;
> }
>
> void block_acct_done(BlockAcctStats *stats, BlockAcctCookie *cookie)
>
--
Best regards,
Vladimir
