On 2014-10-01 18:58, Jens Axboe wrote:
> On 2014-10-01 17:52, Elliott, Robert (Server Storage) wrote:
>>
>>
>>> -----Original Message-----
>>> From: Jens Axboe [mailto:axboe@kernel.dk]
>>> Sent: Tuesday, 30 September, 2014 10:43 PM
>>> To: Elliott, Robert (Server Storage); fio@vger.kernel.org
>>> Cc: Sitsofe Wheeler; Jon Tango
>>> Subject: Re: linux /dev and normal files
>>>
>>> On 2014-09-30 19:17, Jens Axboe wrote:
>>>> On 2014-09-30 19:12, Elliott, Robert (Server Storage) wrote:
>>>>>
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Jens Axboe [mailto:axboe@kernel.dk]
>>>>> ...
>>>>>> I'd much rather keep fio ignorant of any "special" directories,
>>>>>> even if
>>>>>> it means that sometimes you do potentially run into issues like the
>>>>>> above, where you specify a block device that does not exist.
>>>>>
>>>>> How about an option in the script:
>>>>> direct=2   file must exist and be a block device, otherwise skip it
>>>>
>>>> Might be a bit nasty to overload direct= like that. But I'd be open to
>>>> adding an option that says must_be_bdev or something, which can be a
>>>> bool as well.
>>>
>>> Totally untested patch attached (it compiles). There's a new option,
>>> filetype. If not set, if will allow any file type. Can be set to:
>>>
>>> any        default, allow any file type
>>> file       regular file
>>> bdev       block device
>>> chardev    character device
>>> pipe       pipe
>>>
>>> So for your case, you'd set
>>>
>>> filetype=bdev
>>>
>>> and you'd avoid the issue. Note that it only works for files specified
>>> with filename=. Any other way of adding a file (blktrace replay,
>>> opendir=, or fio added files when no filename= given) will ignore the
>>> filetype setting.
>>
>> Tested with 16 devices sdr to sdag, where sdaf and sdag are
>> offline.
>>
>> It prints a message about sdaf and exits, and does not
>> create a normal file in that location:
>> parse    11480 [drive_af]
>> parse    11480 Parsing section [drive_af]
>> file     11480 dup files: 0
>> parse    11480 filename=/dev/sdaf
>> parse    11480
>> parse    11480 [drive_ag]
>> parse    11480 handle_option=filename, ptr=/dev/sdaf
>> parse    11480 __handle_option=filename, type=5, ptr=/dev/sdaf
>> file     11480 add file /dev/sdaf
>> file     11480 resize file array to 1 files
>> fio: dropping file '/dev/sdaf' of wrong type
>> fio: wanted bdev, got file
>> fio: failed parsing filename=/dev/sdaf
>> fio: job drive_af dropped
>> parse    11480 free options
>> parse    11480 free options
>> io       11480 ioengine cpuio unregistered
>> io       11480 ioengine mmap unregistered
>> io       11480 ioengine sync unregistered
>> ...
>>
>> compared to a bdev that exists:
>> parse    11480 handle_option=filename, ptr=/dev/sdae
>> parse    11480 __handle_option=filename, type=5, ptr=/dev/sdae
>> file     11480 add file /dev/sdae
>> file     11480 resize file array to 1 files
>> file     11480 file 0x7f7903703a90 "/dev/sdae" added at 0
>> io       11480 load ioengine libaio
>> parse    11480 init options
>> drive_ae: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio,
>> iodepth=96
>> file     11480 dup files: 1
>> io       11480 load ioengine libaio
>>
>> That is because the do {} while (!ret) loop in
>> __parse_jobs_ini gives up on the first add_job failure.
>> add_job calls parse_options which calls handle_option
>> which fails.
>>
>> It might be better to continue to attempt to run the
>> other jobs.
>
> We should just go for the simpler create/nocreate solution, I prefer
> that. This is too involved, and it's hard to get all the cases right
> since there are a bunch of different ways that files are added. Which
> was why this patch only focused on filename=, since that is the one that
> is the most interesting. But it still isn't pretty. If we add the
> allow_file_create option, it's basically a two-liner change in a few
> places to not use O_CREAT.

That took roughly 4 minutes... Does this work? Set allow_file_create=0 
to disallow creating new files.

-- 
Jens Axboe