Re: [PATCH] xfs_io: v7 add the lseek() SEEK_DATA/SEEK_HOLE support

Eric Sandeen
2013-08-23T15:39:33Z

On 8/23/13 10:18 AM, Mark Tinguely wrote:
> On 08/23/13 10:07, Eric Sandeen wrote:
>> On 8/23/13 9:57 AM, Mark Tinguely wrote:
>>> On 08/23/13 08:34, Eric Sandeen wrote:
>>>> On Aug 23, 2013, at 8:26 AM, Mark Tinguely<tinguely@sgi.com> wrote:
>>>>
>>>>> On 08/22/13 17:45, Eric Sandeen wrote:
>>>>>> On 8/22/13 4:31 PM, Mark Tinguely wrote:
>>>>>>
>>>>>>> Add the lseek SEEK_DATA/SEEK_HOLE support into xfs_io.
>>>>>>> The result from the lseek() call will be printed to the output.
>>>>>>> For example:
>>>>>>>
>>>>>>> xfs_io> seek -h 609k
>>>>>>> HOLE 630784
>>>>>>>
>>>>>>> Signed-off-by: Mark Tinguely<tinguely@sgi.com>
>>>>>>> ---
>>>>>>> version 7 or 8 - Eric what number is this?
>>>>>>
>>>>>> Go for 13, for luck!
>>>>>>
>>>>>> I think this looks ok, I won't torture you any longer. If there's anything
>>>>>> to fix up when it really gets used in earnest we can do it then.
>>>>>>
>>>>>> (it crossed my mind that for the "-r" and "-a" invocations it might be good to print
>>>>>> out the offset which was sent for each SEEK_* "whence," but *shrug*)
>>>>>>
>>>>>> Thanks for all the iterations,
>>>>>>
>>>>>> Reviewed-by: Eric Sandeen<sandeen@redhat.com>
>>>>>
>>>>> Rich, hold off on commit, I can quickly add the whence. We can see how she sails.
>>>>>
>>>> Was just an idle thought... See if it makes sense I guess...
>>>>
>>>> Thanks,
>>>> Eric
>>>
>>>
>>> without whence:
>>> xfs_io> seek -ar 0
>>> HOLE 0
>>> DATA 528384
>>> HOLE 532480
>>> DATA 819200
>>> HOLE 823296
>>>
>>> xfs_io> seek -dh 512k
>>> HOLE 524288
>>> DATA 528384
>>>
>>> xfs_io> seek -rd 0
>>> DATA 528384
>>> DATA 819200
>>>
>>> ============
>>>
>>> after with whence:
>>
>> Don't hate me, but if you do this, now I think it needs a header ;)
>
> I was looking at the output and knew you were going to suggest it.
>
>> I dunno, what do you think, does it have value in general?
>>
>
> for -ar no because we are alternating data and hole - the last result is the new input. But for all the holes and all the data it is an improvement.
>
> The question is should we print the starting offset in only the "-r" option or for all cases to be consistent?

I'd say either make it consistent across all outputs, or add a "-w" to explicitly print the whence, and skip it otherwise.

-Eric