Re: [PATCH] hugetlbfs read() support

[Nick Piggin <nickpiggin@yahoo.com.au>]

Andrew Morton wrote:
> On Thu, 19 Jul 2007 08:51:49 -0700 Badari Pulavarty <pbadari@us.ibm.com> wrote:
>
>
> > > > +		}
> > > > +
> > > > +		offset += ret;
> > > > +		retval += ret;
> > > > +		len -= ret;
> > > > +		index += offset >> HPAGE_SHIFT;
> > > > +		offset &= ~HPAGE_MASK;
> > > > +
> > > > +		page_cache_release(page);
> > > > +		if (ret == nr && len)
> > > > +			continue;
> > > > +		goto out;
> > > > +	}
> > > > +out:
> > > > +	return retval;
> > > > +}
> > >
> > > This code doesn't have all the ghastly tricks which we deploy to handle
> > > concurrent truncate.
> >
> > Do I need to ? Baaahh!!  I don't want to deal with them. 
>
>
> Nick, can you think of any serious consequences of a read/truncate race in
> there?  I can't..

As it doesn't allow writes, then I _think_ it should be OK. If you
ever did want to add write(2) support, then you would have transient
zeroes problems.

But why not just hold i_mutex around the whole thing just to be safe?

--
SUSE Labs, Novell Inc.
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