Re: [RFC PATCH] cogito --- don't overwrite metadata files in place (breaks CoW use)

From: Linus Torvalds <torvalds@osdl.org>
Date: Jul 13, 2005, 21:33 UTC
Message-ID: <Pine.LNX.4.58.0507131425080.17536@g5.osdl.org>
In-Reply-To: <20050713211106.GA12047@taniwha.stupidest.org>

On Wed, 13 Jul 2005, Chris Wedgwood wrote:

Show 5 quoted lines

> 
> I would however like to be able to hardlink more than just the
> _object_ directory --- hardlinking the source is quite nice too.
> Might that be considered safe?  (I'm of course assuming that editors
> do write + rename when saving their buffers).

Hmm.. I don't think it's necessarily wrong, although as you say, your editor had better DTRT. That said, even if your editor doesn't, at least you won't corrupt your git archive, although you might have surprising changes creep into the other side..

But I've not verified that every git program does the right thing...

Search-search-search.. Indeed: at least "git-apply" seems to modify the file in place. That may be the only one, though - and should be easily fixed by adding an "unlink()" (and make it use O_EXCL just to make it easy to grep to verify that we always use O_EXCL with O_WR.*).

entry.c should also add O_EXCL (it seems to already do the unlink).

Anybody want to go through and verify it? I think we should support hardlinked source trees if we can do so easily, and it _looks_ like we're pretty close..

		Linus