From owner-freebsd-current  Tue May 18 10: 4:54 1999
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From: Soren Schmidt <sos@freebsd.dk>
Message-Id: <199905181704.TAA28475@freebsd.dk>
Subject: Re: ATA and afd (LS-120): got it WORKING!
In-Reply-To: <199905181616.JAA03981@dingo.cdrom.com> from Mike Smith at "May 18, 1999  9:16:59 am"
To: mike@smith.net.au (Mike Smith)
Date: Tue, 18 May 1999 19:04:38 +0200 (CEST)
Cc: green@unixhelp.org, current@FreeBSD.ORG
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It seems Mike Smith wrote:
> > 
> > No, it does not work at all with that maximum set. I'm using the disk to hold
> > an FFS filesystem, and mounting it, BTW. See, in the old driver, it limited
> > the transfer, but it ALSO queued the rest of the transfer. AFD doesn't, and
> > I can tell this because I get random parts of kernel memory interspersed with
> > my files (that's the corruption), so I know all of the buffer is not being
> > filled. You need to queue the rest of the transfer too.
> 
> I wrote the original code for this in wfd, and it requeues the transfer
> for just this reason; the layer above doesn't retry the block operation
> for the remaining residual.  I'm not sure this is an error; it's too
> long since I looked at the code, but I think there are some bad things
> that can happen (or were suggested might happen) if you persist in
> retrying the physical I/O.

Well, the code uses d_maxio in many places, just not all regrettably :(
That would be the way to solve this...

-Søren


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