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    SubjectRe: [PATCH 2/2] aio: propogate post-EIOCBQUEUED errors to completion event
    > This is an interesting trick, but I'd like to consider hard whether  
    > the added
    > complexity is worth it. Could you list the various other cases you
    > have in mind
    > which would want to use it ?

    I'm happy to report that the sync case and the
    invalidate_inode_pages2_range() case are the only two which try to
    rewrite 'ret'. I audited all the call paths between aio_{read,write}

    So, sure, maybe we can shuffle the house of cards a little in the
    direction away from having a fs/aio.c helper for the situation by
    simply removing the few current instances of the problem. It won't
    scale as people add problems without knowing about the rule to not
    overwrite -EIOCBQUEUED, but hopefully that won't be a rule for much
    longer :) :).

    For the O_SYNC case we could add another magical test to the is_async
    assignment which won't perform AIO on O_SYNC descriptors.

    > For the invalidate_inode_pages2_range() case, I wonder if the right
    > place to issue this is after the direct IO write has completed and
    > before
    > aio_complete() is issued (somewhat like the way we do
    > bio_check_pages_dirty
    > for DIO reads), rather than after submission when the IO may still
    > not have
    > hit the disk. This would also make the behaviour uniform for
    > synchronous and
    > async cases.

    Hmm, I think I like that. It solves the problem for the current sole
    user of -EIOCBQUEUED without too much disruption.

    > BTW, am I right in interpreting that with your change aio_complete
    > () may
    > trigger an io_getevents() wakeup, before the corresponding event is
    > placed
    > on the ring buffer ?

    Hmm, yeah, it looks like I goofed that.

    I'll roll a patch which does the invalidation down in fs/direct-io.c.

    - z
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      Last update: 2007-02-21 19:37    [W:0.020 / U:0.992 seconds]
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