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From: Miklos Szeredi <miklos@szeredi.hu>
To: Hao Peng <flyingpenghao@gmail.com>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] fuse: fix possible write position calculation error
Date: Wed, 10 Nov 2021 11:40:00 +0100	[thread overview]
Message-ID: <CAJfpegusBqc7AsJK3+bT6Mp08UB3UN-oBn5K1yuzpgAC237DXg@mail.gmail.com> (raw)
In-Reply-To: <CAPm50a+pu0hB0WwjSkaz+F=BJEhD5mEjFfe019cZ7AGdO0t2Ow@mail.gmail.com>

On Fri, 5 Nov 2021 at 08:44, Hao Peng <flyingpenghao@gmail.com> wrote:
>
> On Thu, Nov 4, 2021 at 8:18 PM Miklos Szeredi <miklos@szeredi.hu> wrote:
> >
> > On Wed, 3 Nov 2021 at 02:15, Peng Hao <flyingpenghao@gmail.com> wrote:
> > >
> > > The 'written' that generic_file_direct_write return through
> > > filemap_write_and_wait_range is not necessarily sequential,
> > > and its iocb->ki_pos has not been updated.
> >
> > I don't see the bug, but maybe I'm missing something.  Can you please
> > explain in detail?
> >
> I think we shouldn't add "written" to variable pos.
> generic_file_direct_write:
>                 ....
>                 written = filemap_write_and_wait_range(mapping, pos,
>                                                         pos + write_len - 1);
>                 if (written)  //the number of writes here reflects the
> amount of writeback data

No.  It's actually an error code in this case.

It is confusing, though, so I guess cleaning this up (e.g. rename
"written" to "retval") would make sense.

Thanks,
Miklos

  reply	other threads:[~2021-11-10 10:40 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-03  1:15 [PATCH] fuse: fix possible write position calculation error Peng Hao
2021-11-04 12:17 ` Miklos Szeredi
2021-11-05  7:43   ` Hao Peng
2021-11-10 10:40     ` Miklos Szeredi [this message]
2021-11-11  1:40       ` Hao Peng
  -- strict thread matches above, loose matches on Subject: below --
2021-10-26  2:34 Peng Hao

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