Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala]

On Feb 21, 2007, at 3:31 PM, Andrew Morton wrote:

> On Wed, 21 Feb 2007 16:22:17 -0500 (EST)
> Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>
> > On Wed, 21 Feb 2007, Andrew Morton wrote:
> >
> > > > > It seems like usb-storage and aio are completely off in the weeds.
> > > > > Ideas?
> > > >
> > > > It seems usb-storage should remove some kmalloc and use mempool 
> > > > () for
> > > > urb...  Is someone working on this? And idea?
> > >
> > > I think Pete said that we're supposed to be using GFP_NOIO in there.
> >
> > We _are_ using it.
>
> How admirably prompt.
>
> > > Not that it'll help much: the VM calls throttle_vm_writeout() for  
> > > GFP_NOIO
> > > and GFP_NOFS allocations, which is a bug.  Because if the caller  
> > > holds
> > > locks which prevent filesystem or IO progress, we deadlock.
> > >
> > > I'll fix the VM if someone else fixes USB ;)
> >
> > What else needs to be fixed?
>
> Would be nice if someone can confirm that this fixes it:

Doesn't seem to help my problem in a quick test, will get more data  
in the morning.

- k
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