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

[Jens Axboe <axboe@kernel.dk>]

On 12/19/25 4:55 PM, Damien Le Moal wrote:
> 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.

Agree, REQ_OP_ZONE_XXX means nothing in userspace.

-- 
Jens Axboe