Re: [PATCH] Use of getblk differs between locations

From: Glauber de Oliveira Costa
Date: Mon Oct 10 2005 - 18:23:51 EST

On Tue, Oct 11, 2005 at 01:16:59AM +0200, Mikulas Patocka wrote:
> On Mon, 10 Oct 2005, Glauber de Oliveira Costa wrote:
> >
> >>What should a filesystem driver do if it can't suddenly read or write any
> >>blocks on media?
> >
> >Maybe stopping gracefully, warn about what happened, and let the system
> >keep going. You may be right about your main filesystem, but in the case
> >I'm running, for example, my system in an ext3 filesystem, and have a
> >vfat from a usb key. Should my system really hang because I'm not able
> >to read/write to the device?
> getblk won't fail because of I/O error --- it can fail only because of
> memory management bugs. I think it's right to stop the system in that case
> --- it's better than silently corrupting data on any device.
> Mikulas
In the code, we see:

if (unlikely(size & (bdev_hardsect_size(bdev)-1) ||
(size < 512 || size > PAGE_SIZE))) {

This is where __getblk_slow, and thus, __getblk fails, and it does not
seem to be due to any memory management bug.

Glauber de Oliveira Costa
IBM Linux Technology Center - Brazil
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