From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 11 Jun 2008 02:39:16 GMT
Subject: Re: git bugs
Message-ID: <alpine.LFD.1.10.0806101935130.3101@woody.linux-foundation.org>
In-Reply-To: <832adb090806101931y754fa6b7nfcb58a9c34f0c582@mail.gmail.com>



On Tue, 10 Jun 2008, Ben Lynn wrote:
>
> Ah, I hadn't seen that. Yes, it is better to use the first write as
> the timestamp. Would this catch everything? If the filesystem clock is
> monotonically increasing and consistent then with this setup, you can
> touch files even as they are being indexed? (Disregarding nonsense
> like changing sizes by 2^32.)

Yes, I think that at that point it would protect against arbitrary 
modifications even concurrently to index file creation.

That said, I don't think you even need a new index file format. We could 
just do a stat() on starting the index file creation, and then do a 
futimes() system call at the end to re-set the mtime to the beginning 
before we rename it back over the old index file.

		Linus