Re: [PATCH V2] blktrace: log dropped REQ_OP_ZONE_XXX events ver1

[Damien Le Moal <dlemoal@kernel.org>]

On 10/29/25 02:32, Chaitanya Kulkarni wrote:
> Add informational messages during blktrace setup when version 1 tools
> are used on kernels with CONFIG_BLK_DEV_ZONED enabled. This alerts users
> that REQ_OP_ZONE_* events will be dropped and suggests upgrading to
> blktrace tools version 2 or later.
> 
> The warning is printed once during trace setup to inform users about
> the limitation without spamming the logs during tracing operations.
> Version 2 blktrace tools properly handle zone management operations
> (zone reset, zone open, zone close, zone finish, zone append) that
> were added for zoned block devices.
> 
> Example output:
> 
> blktests (master) # ./check blktrace
> blktrace/001 (blktrace zone management command tracing)      [passed]
>     runtime  0.110s  ...  3.917s
> blktrace/002 (blktrace ftrace corruption with sysfs trace)   [passed]
>     runtime  0.333s  ...  0.608s
> blktests (master) # dmesg -c
> [   57.610592] blktrace: nullb0: blktrace events for REQ_OP_ZONE_XXX will be dropped
> [   57.610603] blktrace: use blktrace tools version >= 2 to track REQ_OP_ZONE_XXX
> 
> This helps users understand why zone operation traces may be missing
> when using older blktrace tool versions with modern kernels that
> support REQ_OP_ZONE_XXX in blktrace.
> 
> Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
> ---
> v1->v2 :-
> 
> Remove the extra () around IS_ENABLED(CONFIG_BLK_DEV_ZONED). (Jens)
> Add a space after device name in first pr_info(). (Jens)
> 
> ---
>  kernel/trace/blktrace.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index e4f26ddb7ee2..4a37d9aa0481 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -739,6 +739,12 @@ static void blk_trace_setup_finalize(struct request_queue *q,
>  	 */
>  	strreplace(buts->name, '/', '_');
>  
> +	if (version == 1 && IS_ENABLED(CONFIG_BLK_DEV_ZONED)) {
> +		pr_info("%s: blktrace events for REQ_OP_ZONE_XXX will be dropped\n",
> +				name);
> +		pr_info("use blktrace tools version >= 2 to track REQ_OP_ZONE_XXX\n");

Please change REQ_OP_ZONE_XXX to "zone operations" in these messages. That is a
little more general, so better I think since we also trace zone write
plug/unplug events, which are not REQ_OP_ZONE_XXX.

With that done,

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

> +	}
> +
>  	bt->version = version;
>  	bt->act_mask = buts->act_mask;
>  	if (!bt->act_mask)


-- 
Damien Le Moal
Western Digital Research