Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for uptodate

From	Hugh Dickins <hughd@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for uptodate
Date	2015-11-03 16:50 +0100
Message-ID	<qqM0p-4Hz-13@gated-at.bofh.it> (permalink)
References	(1 earlier) <qpXKh-6S1-7@gated-at.bofh.it> <qqaoa-6f8-7@gated-at.bofh.it> <qql9T-4AW-5@gated-at.bofh.it> <qqzZg-56X-1@gated-at.bofh.it> <qqG4F-OO-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Tue, 3 Nov 2015, Boaz Harrosh wrote:
> On 11/03/2015 04:49 AM, Hugh Dickins wrote:
> > On Mon, 2 Nov 2015, Boaz Harrosh wrote:
> >>
> >> Do you think the code is actually wrong as is?
> > 
> > Not that I know of: just a little too complicated and confusing.
> > 
> > But becomes slightly wrong if my simplification to page migration
> > goes through, since that introduces an instant when PageDirty is set
> > before the new page contains the correct data and is marked Uptodate.
> > Hence my patch.
> > 
> >>
> >> BTW: Very similar code is in fs/nfs/objlayout/objio_osd.c::__r4w_get_page
> > 
> > Indeed, the patch makes the same adjustment to that code too.
> > 
> 
> OK thanks. Let me setup and test your patch. On top of 4.3 is good?
> I'll send you a tested-by once I'm done.

Great, thanks Boaz, that will help a lot.  On top of 4.3 very good.

(Of course, that will not test the rare page migration race I shall
introduce later; but it will test that you're doing the right thing
with this change at your end, when you will be safe against the race.)

Hugh
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Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for uptodate Boaz Harrosh <ooo@electrozaur.com> - 2015-11-01 11:10 +0100
  Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for  uptodate Hugh Dickins <hughd@google.com> - 2015-11-02 00:40 +0100
    Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for uptodate Boaz Harrosh <ooo@electrozaur.com> - 2015-11-02 12:10 +0100
      Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for  uptodate Hugh Dickins <hughd@google.com> - 2015-11-03 04:00 +0100
        Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for uptodate Boaz Harrosh <boaz@plexistor.com> - 2015-11-03 10:30 +0100
          Re: [PATCH] osd fs: __r4w_get_page rely on PageUptodate for  uptodate Hugh Dickins <hughd@google.com> - 2015-11-03 16:50 +0100

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