Re: [PATCH] hugetlbfs read() support

Nick Piggin
2007-07-20T06:13:04Z

(sorry if this is a resend... something bad seems to have happened to me)

Andrew Morton wrote:
> On Thu, 19 Jul 2007 08:51:49 -0700 Badari Pulavarty <pbadari@us.ibm.com> wrote:

>>>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 I'm not completely sure.. we've had a lot of (and still have
some known and probably unknown) bugs just in that single
generic_mapping_read function, most of which are due to our rabid
aversion to doing any locking whatsoever there.

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

--
SUSE Labs, Novell Inc.