Re: [PATCH] gc: support temporarily preserving garbage

From: Brodie Rao <brodie@sf.io>
Date: Dec 3, 2014, 21:21 UTC
Message-ID: <CADQoFhyxFNzazsEaE6Bk2W_KDhogBho8vgJXkDDPsYvC46ZX5Q@mail.gmail.com>
In-Reply-To: <20141117213442.GD15880@peff.net>

On Mon, Nov 17, 2014 at 1:34 PM, Jeff King <peff@peff.net> wrote:

Show 16 quoted lines

> On Fri, Nov 14, 2014 at 03:01:05PM -0800, Junio C Hamano wrote:
>
>> >  23 files changed, 375 insertions(+), 7 deletions(-)
>> [...]
>>
>> I am not sure if this much of code churn is warranted to work around
>> issues that only happen on repositories on NFS servers that do not
>> keep open-but-deleted files available.  Is it an option to instead
>> have a copy of repository locally off NFS?
>
> I think it is also not sufficient. This patch seems to cover only
> objects. But we assume that we can atomically rename() new versions of
> files into place whenever we like without disrupting existing readers.
> This is the case for ref updates (and packed-refs), as well as the index
> file.  The destination end of the rename is an unlink() in disguise, and
> would be susceptible to the same problems.

I'm not aware of renaming over files happening anywhere in gc-related code. Do you think that's something that would need to be addressed in the rest of the code base before going forward with this garbage directory approach? If so, do you have any suggestions on how to tackle that problem?