From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Thu, 19 Apr 2012 07:02:30 GMT
Subject: Re: What's cooking in git.git (Apr 2012, #06; Sun, 15)
Message-ID: <CACsJy8A6iLzW8ZtV97Fvat_e=Totzuh-hQ8mDyf9c5a=JC3u9Q@mail.gmail.com>
In-Reply-To: <4F8FB4A0.7090403@viscovery.net>

Hi,

I've been busy and have not had time to look into this yet...

2012/4/19 Johannes Sixt <j.sixt@viscovery.net>:
> I don't see any mutual exclusion happening in this chain. Perhaps it is
> not needed, provided that the pread() call in get_data_from_pack is
> atomic. But our git_pread() from compat/pread.c, which we use on Windows,
> is not atomic.
>
> :-(
>
> I don't think that it is possible to make git_pread() atomic because it
> would have to be protected against all file accesses that can modify the
> file position.
>
> Is get_data_from_pack() the only function that accesses the pack data?
> Then we could add some mutual exclusion there.

I believe so. And index-pack only accesses the pack via pread, no other means.
-- 
Duy