Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <CAJDTihz-rFb2SGaxZsQnXGnee_2qW_ynhPe=tZ4yzQBSV_KQ1g@mail.gmail.com>
 <20180904075347.GH11854@BitWizard.nl> <CAJDTihzqn3whQ47uUOxGYk4Je4S10ehNEQCtfb=j--iCsdDqgQ@mail.gmail.com>
 <20180904092938.GJ11854@BitWizard.nl>
In-Reply-To: <20180904092938.GJ11854@BitWizard.nl>
From:   =?UTF-8?B?54Sm5pmT5Yas?= <milestonejxd@gmail.com>
Date:   Tue, 4 Sep 2018 18:45:54 +0800
Message-ID: <CAJDTihyhA7Q_O=DhdPxLquReY1CO=3y3XgZtZ5pA5kY+DTAvMg@mail.gmail.com>
Subject: Re: POSIX violation by writeback error
To:     R.E.Wolff@bitwizard.nl
Cc:     jlayton@redhat.com, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Sep 4, 2018 at 5:29 PM Rogier Wolff <R.E.Wolff@bitwizard.nl> wrote:
>
> On Tue, Sep 04, 2018 at 04:58:59PM +0800, =E7=84=A6=E6=99=93=E5=86=AC wro=
te:
>
> > As for suggestion, maybe the error flag of inode/mapping, or the entire=
 inode
> > should not be evicted if there was an error. That hopefully won't take =
much
> > memory. On extreme conditions, where too much error inode requires stay=
ing
> > in memory, maybe we should panic rather then spread the error.
>
> Again you are hoping it will fit in memory. In an extreme case it
> won't fit in memory. Tyring to come up with heuristics about when to
> remember and when to forget such things from the past is very
> difficult.

The key point is to report errors, not to hide it from user space to
prevent further errors/damage,
and that is also what POSIX wants.

And, storing inode/mapping/error_flag in memory is quite different
from storing the data itself.
They are tiny and only increase per inode rather than per error page.
>
> Think of my comments as: "it's harder than you think", not as "can't
> be done".
>
>         Roger.
>
> --
> ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 *=
*
> **    Delftechpark 26 2628 XH  Delft, The Netherlands. KVK: 27239233    *=
*
> *-- BitWizard writes Linux device drivers for any device you may have! --=
*
> The plan was simple, like my brother-in-law Phil. But unlike
> Phil, this plan just might work.