Re: dd/mke2fs on loopback hangs

Petar Bogdanovic
2007-11-13T09:36:18Z

On Tue, Nov 06, 2007 at 10:04:51PM +0100, Milan Broz wrote:
> Petar Bogdanovic wrote:
> > I experience some strange problems with my loopback-on-ext3-setup.
> > After creating a plain `zeroed' dummy-file and doing a /dev/loop/0 on
> > it, every dd or mke2fs hangs while doing certain write()s. Here are the
> > steps just in order to show, how simple the setup is:
> ...
>
> > P.S: $ uname -a
> > Linux pintail 2.6.23-ARCH #1 SMP PREEMPT Sat Oct 27 09:04:14 UTC
> > 2007 i686 Intel(R) Pentium(R) M processor 1.70GHz GenuineIntel
> > GNU/Linux
>
> Hi Petar,
>
> I saw similar bug report for dm-crypt over loop but reproducible even
> on stand-alone loop devices - see http://bugzilla.kernel.org/show_bug.cgi?id=8020
>
> The problem was caused by loop io stalling in balance_dirty_pages.
>
> Per BDI dirty limit patchset (included in 2.6.24-rc) fixed it.

Indeed, the problem disappeared on 2.6.24-rc2. Thanks again for the
hint!

Petar