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Re: Support for filesystem snapshots (?)

From: Vincent Lefevre <vincent-svn_at_vinc17.net>
Date: Tue, 3 Aug 2010 20:43:56 +0200

On 2010-08-03 15:12:19 +0200, Stefan Sperling wrote:
> On Tue, Aug 03, 2010 at 02:36:41PM +0200, Vincent Lefevre wrote:
> > On 2010-08-03 12:56:28 +0200, Stefan Sperling wrote:
> > > Subversion carefully flushes file buffers after writing revision files.
> >
> > What do you mean by "flushes file buffers"? A call to fflush()?
> > Or a call to sync() or fsync() too?
> >
> > Assuming the filesystem is on a remote machine (say, NFS), the
> > necessary needs to be done on the client side: the NFS server
> > cannot take into account the kernel-level buffers of the client.
> Subversion calls apr_file_flush(). What that does on which platform
> depends on APR (and could theoretically change over time).
> I'm not sure what else you suggest we should do to avoid the (from
> my point of view non-existent) bug you were talking about.

Well, not flushing the buffers at some low level is not necessarily
a bug. But in such a case the user has to accept the consequences,
such as a filesystem snapshot not providing a consistent state of a
Subversion repository.

Vincent Lefèvre <vincent@vinc17.net> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)
Received on 2010-08-03 20:44:34 CEST

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