utimes()/gid problem & CoW Link-Breaking

[Michael Stone]

Folks,

Herbert Poetzl took a look at our utimes()/gid problem and has produced
a patch that he thinks will fix the bug:

http://vserver.13thfloor.at/Experimental/delta-cow-fix13.diff

His patch basically confirms that our work-around for updating
(rsync'ing twice) is correct; therefore, I feel quite good about
proceeding with live updates.

However, Andres or I should try to test the patch tomorrow to see if we
can merge it since, while we have a work-around for updates, we're still
at risk of uid/gid corruption when we're running inside a shallow-copied
COW-linked filesystem.

Michael