Re: [PATCH 0/2] mmc: rtsx_pci: Enable support for erase/discard/trim requests

[Mauro Santos <registo.mailling@gmail.com>]

On 27-07-2016 23:02, Ulf Hansson wrote:
> On 27 July 2016 at 22:35, Mauro Santos <registo.mailling@gmail.com> wrote:
>> On 27-07-2016 13:45, Ulf Hansson wrote:
>>> Mauro, I have applied this for my next branch (based on 4.7), to allow
>>> it to be easily tested.
>>>
>>> Just clone my tree below and build/replace your kernel.
>>> git://git.linaro.org/people/ulf.hansson/mmc.git next
>>>
>>> Running fstrim and checking blkdiscard should be sufficient as test cases.
>>>
>>> Don't hesitate to ask if problems occurs!
>>>
>>> Kind regards
>>> Uffe
>>>
>>
>> I've tested both blkdiscard and fstrim (on ext4) and they both worked.
>>
>> I haven't noticed any errors or warnings on dmesg or complaints from
>> blkdiscard/fstrim.
>>
>> If there are any more specific tests you would like me to do let me know.
> 
> Perhaps just run some dd operation to read and write some data to the
> card, then I am happy. :)
> 

Maybe I should have mentioned in my previous email, I have used the ext4
formatted fs to write some files, if you want me to still test with dd
let me know.

I have tested it like this:

- Filesystem was not mounted with the discard option.
- Almost fill the card with files, determine md5sum for all files and
reboot to make sure there are no cached files in ram
- Delete half of the files, fstrim -v (trimmed space looks about right),
check md5sum of remaining files - no problems here.
- fsck -f filesystem - no problems detected.

After this I have written more data to the card and checked the md5sums,
but I already forgot the exact sequence, I was looking for any sign that
using fstrim would delete more than it should have or that writing new
files might for some reason corrupt the old files.

I have confirmed that blkdiscard does work, the card returns zeros for
the few sectors I've checked, but I haven't confirmed that fstrim is
doing what it is supposed to do, the same applies to the case where the
filesystem is mounted with the discard option (quick google search
didn't return recipe for going from file->lba/sector or inode->lba/sector).

That said, given that blkdiscard works I'm assuming fstrim (and the
discard option) also work. I can check that if you want, but I would
need some pointers on how to do it. I could also check fstrim on a well
used f2fs formatted card where data should be all over the place by now.

> Thanks a lot for your help in testing, I will apply a tested-by tag
> from you, unless you object.
> 

No objections.

> Kind regards
> Uffe
> 

Regards,
Mauro Santos