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Re: [PATCH 1/2] direct-io: move aio_complete into ->end_io

To: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Subject: Re: [PATCH 1/2] direct-io: move aio_complete into ->end_io
From: Jan Kara <jack@xxxxxxx>
Date: Fri, 25 Jun 2010 12:35:50 +0200
Cc: Jan Kara <jack@xxxxxxx>, linux-fsdevel@xxxxxxxxxxxxxxx, xfs@xxxxxxxxxxx, linux-ext4@xxxxxxxxxxxxxxx
In-reply-to: <20100625063610.GA4128@xxxxxxxxxxxxx>
References: <20100622122144.302857146@xxxxxxxxxxxxxxxxxxxxxx> <20100622123113.011371666@xxxxxxxxxxxxxxxxxxxxxx> <20100624215922.GE3345@xxxxxxxxxxxxx> <20100625063610.GA4128@xxxxxxxxxxxxx>
User-agent: Mutt/1.5.20 (2009-06-14)
On Fri 25-06-10 02:36:10, Christoph Hellwig wrote:
> On Thu, Jun 24, 2010 at 11:59:22PM +0200, Jan Kara wrote:
> >   Moreover the async testing you do does not seem to be completely right.
> > dio->is_async is a flag that controls whether dio code waits for IO to be
> > completed or not. In particular it is not set for AIO that spans beyond
> > current i_size so it does not seem to be exactly what you need (at least
> > for ext4 it isn't). I think that is_sync_kiocb() is a test that should be
> > used to recognize AIO - and that has an advantage that you don't have to
> > pass the is_async flag around.
> No.  is_sync_kiocb() means the ioctb was not intended as sync I/O from
> the start.  But we can only call aio_complete when we returned
> -EIOCBQUEUED from ->aio_read/write.  Take a look at the comment near the
> end of direct_io_worker().
  Ah, I see. Thanks for explanation. It's ugly but I also don't see a
nicer way how to handle this.

Jan Kara <jack@xxxxxxx>

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