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

[Kumar Gala]

> > > > 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.

Well, I didn't realize the patch you sent via mm-commits and the one  
here are actually different.  I noticed that mm-commits one has:

+       if ((gfp_mask & (__GFP_FS|__GFP_IO)) != __GFP_FS|__GFP_IO) {

vs

+       if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {

The second seems to make more sense.  I tested with the first last  
night which didn't help.

With the proper patch in place things look good.  Is this a candidate  
for 2.6.20-stable?

- k
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