Messages in this thread | | | Subject | Re: filesystem transactions API | From | Trond Myklebust <> | Date | Tue, 26 Apr 2005 11:19:42 -0400 |
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ty den 26.04.2005 Klokka 11:01 (-0400) skreiv John Stoffel: > >>>>> "Jamie" == Jamie Lokier <jamie@shareable.org> writes: > > Jamie> No. A transaction means that _all_ processes will see the > Jamie> whole transaction or not. > > This is really hard. How do you handle the case where process X > starts a transaction modifies files a, b & c, but process Y has file b > open for writing, and never lets it go? Or the file gets unlinked?
That is why implementing it as a form of lock makes sense.
> Jamie> For example, you can use transactions for distro package > Jamie> management: a whole update of a package would be a single > Jamie> transaction, so that at no time does any program see an > Jamie> inconsistent set of files. See why _every_ process in the > Jamie> system must have the same view? > > What about programs that are already open and running? > > It might be doable in some sense, but I can see that details are > really hard to get right. Esp without breaking existing Unix > semantics.
Wrong.
Cheers, Trond -- Trond Myklebust <trond.myklebust@fys.uio.no>
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