Re: [PATCH v2] repack: Add option to preserve and prune old pack files

[Junio C Hamano <gitster@pobox.com>]

James Melvin <jmelvin@codeaurora.org> writes:

> The new --preserve-and-prune option renames old pack files
> instead of deleting them after repacking and prunes previously
> preserved pack files.
>
> This option is designed to prevent stale file handle exceptions
> during git operations which can happen on users of NFS repos when
> repacking is done on them. The strategy is to preserve old pack files
> around until the next repack with the hopes that they will become
> unreferenced by then and not cause any exceptions to running processes
> when they are finally deleted (pruned).

This certainly is simpler than the previous one, but if you run

	git repack --preserve-and-prune 
	sleep for N minutes
	git repack --preserve-and-prune 

the second "repack" will drop the obsoleted packs that were
preserved by the first one no matter how short the value of N is,
no?

I suspect that users would be more comfortable with something based
on expiration timestamp that gives them a guaranteed grace period,
e.g. "--preserve-expire=8.hours", like how we expire reflog entries
and loose objects.

Perhaps builtin/prune.c can be a source of inspiration?