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    SubjectRe: [patch 1/2] mm: dont clear PG_uptodate in invalidate_complete_page2()
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    On Tue, 8 Jul 2008, Nick Piggin wrote:
    > If dirty can't happen, the caller should just use the truncate.
    > The creation of this "invalidate 2" thing was just papering over
    > problems in the callers.

    Dirty *can* happen. The difference between truncate_inode_pages() and
    invalidate_inode_pages2() is that the former just throws away dirty
    pages, while the latter can do something about them through
    ->launder_page().

    > But anyway your point is taken -- caller doesn't really handle failure.

    Yes.

    > > Right. I think leaving PG_uptodate on invalidation is actually a
    > > rather clean solution compared to the alternatives.
    >
    > Note that files can be truncated in the middle too, so you can't
    > just fix one case that happens to hit you, you'd have to fix things
    > consistently.

    Hmm, OK.

    > But...
    >
    >
    > > Well, other than my original proposal, which would just have reused
    > > the do_generic_file_read() infrastructure for splice. I still don't
    > > see why we shouldn't use that, until the whole async splice-in thing
    > > is properly figured out.
    >
    > Given the alternatives, perhaps this is for the best, at least for
    > now.

    Yeah. I'm not at all opposed to improving splice to be able to do all
    sorts of fancy things like async splice-in, and stealing of pages.
    But it's unlikely that I will have the motivation to implement any of
    them just to fix this bug.

    Miklos


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