From: Gao Xiang <hsiangkao@aol.com>
To: Jerome Glisse <jglisse@redhat.com>
Cc: lsf-pc@lists.linux-foundation.org,
Andrea Arcangeli <aarcange@redhat.com>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [LSF/MM/BPF TOPIC] Generic page write protection
Date: Wed, 22 Jan 2020 14:21:36 +0800 [thread overview]
Message-ID: <20200122062122.GA10893@hsiangkao-HP-ZHAN-66-Pro-G1> (raw)
In-Reply-To: <20200122060951.GA77704@redhat.com>
On Tue, Jan 21, 2020 at 10:09:51PM -0800, Jerome Glisse wrote:
> On Wed, Jan 22, 2020 at 01:52:26PM +0800, Gao Xiang wrote:
> > On Tue, Jan 21, 2020 at 09:21:18PM -0800, Jerome Glisse wrote:
> >
> > <snip>
> >
> > >
> > > The block device code only need the mapping on io error and they are
> > > different strategy depending on individual fs. fs using buffer_head
> > > can easily be updated. For other they are different solution and they
> > > can be updated one at a time with tailor solution.
> >
> > If I did't misunderstand, how about post-processing fs code without
> > some buffer_head but page->private used as another way rather than
> > a pointer? (Yes, some alternative ways exist such as hacking struct
> > bio_vec...)
>
> The ultimate answer is that page write protection will not be allow
> for some filesystem (that's how the patchset is designed in fact so
> that things can be merge piecemeal). But they are many way to solve
> the io error reporting and that's one of the thing i would like to get
> input on.
>
> >
> > I wonder the final plan on this from the community, learn new rule
> > and adapt my code anyway.. But in my opinion, such reserve way
> > (page->mapping likewise) is helpful in many respects, I'm not sure
> > we could totally get around all cases without it elegantly...
>
> I still need to go read what it is you are trying to achieve. But i
> do not see any reason to remove page->mapping
I could say it's a huge project :) and I mean there may be some other
options to "insert a pointer directly or indirectly to struct page. "
However, I agree the current page->mapping rule is complicated to be
sorted out in words and make full use it :)
Thanks,
Gao Xiang
next prev parent reply other threads:[~2020-01-22 6:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 2:32 [LSF/MM/BPF TOPIC] Generic page write protection jglisse
2020-01-22 4:28 ` Gao Xiang
2020-01-22 5:21 ` Jerome Glisse
2020-01-22 5:52 ` Gao Xiang
2020-01-22 6:09 ` Jerome Glisse
2020-01-22 6:21 ` Gao Xiang [this message]
2020-01-22 4:41 ` John Hubbard
2020-01-22 18:27 ` [Lsf-pc][LSF/MM/BPF " John Hubbard
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