2023-12-05 12:50:07

by Thorsten Leemhuis

[permalink] [raw]
Subject: Re: [regressions] ntfs3: empty file on update without forced cache drop

[adding a bunch of people and two lists to the recipients, as Konstantin
apparently hasn't sent any mail to any lists archived on lore for ~six
weeks; maybe someone knows what's up or is willing to help out]

On 27.11.23 07:18, Thorsten Leemhuis wrote:
> Hi, Thorsten here, the Linux kernel's regression tracker.
>
> Konstantin, I noticed a regression report in bugzilla.kernel.org.
> Apparently it's cause by a change of yours.
>
> As many (most?) kernel developers don't keep an eye on bugzilla, I
> decided to forward it by mail. Note, you have to use bugzilla to reach
> the reporter, as I sadly[1] can not CCed them in mails like this.
>
> Quoting from https://bugzilla.kernel.org/show_bug.cgi?id=218180 :

Konstantin, are you still around? Would be great if you could look into
this regression, as this sounds somewhat worrying.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

#regzbot poke

>> The problem I am facing is the following:
>> 1. I mount an NTFS partition via NTFS3
>> 2. I create a file
>> 3. I write to the file
>> 4. The file is empty
>> 5. I remount the partition
>> 6. The file has the changes I made before the remount
>>
>> I can avoid the remount by doing:
>> sudo sysctl vm.drop_caches=3
>
> See the ticket for more details. It according to the report happens
> still happens with 6.7-rc2, but not with 6.1.y. The reporter bisected
> the problem to ad26a9c84510af ("fs/ntfs3: Fixing wrong logic in
> attr_set_size and ntfs_fallocate") [v6.2-rc1].
>
> Side note: while briefly checking lore for existing problems caused by
> that change I noticed two syzbot reports about it that apparently nobody
> looked into:
>
> https://lore.kernel.org/all/[email protected]/
> https://lore.kernel.org/all/[email protected]/
>
> [TLDR for the rest of this mail: I'm adding this report to the list of
> tracked Linux kernel regressions; the text you find below is based on a
> few templates paragraphs you might have encountered already in similar
> form.]
>
> BTW, let me use this mail to also add the report to the list of tracked
> regressions to ensure it's doesn't fall through the cracks:
>
> #regzbot introduced: ad26a9c84510af
> https://bugzilla.kernel.org/show_bug.cgi?id=218180
> #regzbot title: ntfs3: empty file on update without forced cache drop
> #regzbot ignore-activity
>
> This isn't a regression? This issue or a fix for it are already
> discussed somewhere else? It was fixed already? You want to clarify when
> the regression started to happen? Or point out I got the title or
> something else totally wrong? Then just reply and tell me -- ideally
> while also telling regzbot about it, as explained by the page listed in
> the footer of this mail.
>
> Developers: When fixing the issue, remember to add 'Link:' tags pointing
> to the report (e.g. the buzgzilla ticket and maybe this mail as well, if
> this thread sees some discussion). See page linked in footer for details.
>
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> --
> Everything you wanna know about Linux kernel regression tracking:
> https://linux-regtracking.leemhuis.info/about/#tldr
> If I did something stupid, please tell me, as explained on that page.
>
> [1] because bugzilla.kernel.org tells users upon registration their
> "email address will never be displayed to logged out users"
>
>


2024-01-21 09:14:30

by Thorsten Leemhuis

[permalink] [raw]
Subject: Re: [regressions] ntfs3: empty file on update without forced cache drop

On 05.12.23 13:49, Linux regression tracking (Thorsten Leemhuis) wrote:
> [adding a bunch of people and two lists to the recipients, as Konstantin
> apparently hasn't sent any mail to any lists archived on lore for ~six
> weeks; maybe someone knows what's up or is willing to help out]

[CCing Linus now as well]

JFYI for the VFS maintainers and everyone else who might care:

Konstantin afaics still did not look into below regression. Neither did
anyone else afaics.

But Konstantin is still around, as he recently showed up to post a patch
for review:
https://lore.kernel.org/all/[email protected]/

I replied to it in the hope of catch his attention and make him look at
this regression, but that did not work out.

So it seems we sadly are kinda stuck here. :-/

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

> On 27.11.23 07:18, Thorsten Leemhuis wrote:
>> Hi, Thorsten here, the Linux kernel's regression tracker.
>>
>> Konstantin, I noticed a regression report in bugzilla.kernel.org.
>> Apparently it's cause by a change of yours.
>>
>> As many (most?) kernel developers don't keep an eye on bugzilla, I
>> decided to forward it by mail. Note, you have to use bugzilla to reach
>> the reporter, as I sadly[1] can not CCed them in mails like this.
>>
>> Quoting from https://bugzilla.kernel.org/show_bug.cgi?id=218180 :
>
> Konstantin, are you still around? Would be great if you could look into
> this regression, as this sounds somewhat worrying.
>
>>> The problem I am facing is the following:
>>> 1. I mount an NTFS partition via NTFS3
>>> 2. I create a file
>>> 3. I write to the file
>>> 4. The file is empty
>>> 5. I remount the partition
>>> 6. The file has the changes I made before the remount
>>>
>>> I can avoid the remount by doing:
>>> sudo sysctl vm.drop_caches=3
>>
>> See the ticket for more details. It according to the report happens
>> still happens with 6.7-rc2, but not with 6.1.y. The reporter bisected
>> the problem to ad26a9c84510af ("fs/ntfs3: Fixing wrong logic in
>> attr_set_size and ntfs_fallocate") [v6.2-rc1].
>>
>> Side note: while briefly checking lore for existing problems caused by
>> that change I noticed two syzbot reports about it that apparently nobody
>> looked into:
>>
>> https://lore.kernel.org/all/[email protected]/
>> https://lore.kernel.org/all/[email protected]/
>> [...]
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

#regzbot poke

2024-01-26 13:29:36

by Konstantin Komarov

[permalink] [raw]
Subject: Re: [regressions] ntfs3: empty file on update without forced cache drop

On 21.01.2024 12:14, Thorsten Leemhuis wrote:
> On 05.12.23 13:49, Linux regression tracking (Thorsten Leemhuis) wrote:
>> [adding a bunch of people and two lists to the recipients, as Konstantin
>> apparently hasn't sent any mail to any lists archived on lore for ~six
>> weeks; maybe someone knows what's up or is willing to help out]
> [CCing Linus now as well]
>
> JFYI for the VFS maintainers and everyone else who might care:
>
> Konstantin afaics still did not look into below regression. Neither did
> anyone else afaics.
>
> But Konstantin is still around, as he recently showed up to post a patch
> for review:
> https://lore.kernel.org/all/[email protected]/
>
> I replied to it in the hope of catch his attention and make him look at
> this regression, but that did not work out.
>
> So it seems we sadly are kinda stuck here. :-/
>
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
>
>> On 27.11.23 07:18, Thorsten Leemhuis wrote:
>>> Hi, Thorsten here, the Linux kernel's regression tracker.
>>>
>>> Konstantin, I noticed a regression report in bugzilla.kernel.org.
>>> Apparently it's cause by a change of yours.
>>>
>>> As many (most?) kernel developers don't keep an eye on bugzilla, I
>>> decided to forward it by mail. Note, you have to use bugzilla to reach
>>> the reporter, as I sadly[1] can not CCed them in mails like this.
>>>
>>> Quoting from https://bugzilla.kernel.org/show_bug.cgi?id=218180 :
>> Konstantin, are you still around? Would be great if you could look into
>> this regression, as this sounds somewhat worrying.
>>
>>>> The problem I am facing is the following:
>>>> 1. I mount an NTFS partition via NTFS3
>>>> 2. I create a file
>>>> 3. I write to the file
>>>> 4. The file is empty
>>>> 5. I remount the partition
>>>> 6. The file has the changes I made before the remount
>>>>
>>>> I can avoid the remount by doing:
>>>> sudo sysctl vm.drop_caches=3
>>> See the ticket for more details. It according to the report happens
>>> still happens with 6.7-rc2, but not with 6.1.y. The reporter bisected
>>> the problem to ad26a9c84510af ("fs/ntfs3: Fixing wrong logic in
>>> attr_set_size and ntfs_fallocate") [v6.2-rc1].
>>>
>>> Side note: while briefly checking lore for existing problems caused by
>>> that change I noticed two syzbot reports about it that apparently nobody
>>> looked into:
>>>
>>> https://lore.kernel.org/all/[email protected]/
>>> https://lore.kernel.org/all/[email protected]/
>>> [...]
> --
> Everything you wanna know about Linux kernel regression tracking:
> https://linux-regtracking.leemhuis.info/about/#tldr
> If I did something stupid, please tell me, as explained on that page.
>
> #regzbot poke
Hello Thorsten,

I apologize for the horrible delay in responding to the bug. I was able
to reproduce it in a scenario involving a compressed file. The patch
will be ready within the next few days (the response in Bugzilla will
also follow).

Best regards,
Konstantin