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Subject: Re: ext4 features
From: Bernd Petrovitsch <bernd@firmix.at>
To: Bill Davidsen <davidsen@tmr.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>, Ric Wheeler <ric@emc.com>,
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Organization: Firmix Software GmbH
Date: Fri, 07 Jul 2006 10:09:49 +0200
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On Thu, 2006-07-06 at 23:16 -0400, Bill Davidsen wrote:
> Trond Myklebust wrote:
[...]
> >I repeat: you do _not_ need high res ctime/mtime updates in order to
> >figure out whether or not you need to do a daily backup on your file.
> >You do need it in order to figure out if the page you just read in from
> >your NFS server 2 microseconds ago is still valid.
> >
> In most cases you don't care and would be using locking if you did. The 
> old value was valid when you read it, the new value is valid, and if 
> data is changing in 2us and the change matters, you can't process the 
> data before it changes again (or at least may change).

Do you never use `make` on NFS-mounted filesystems (for e.g. kernel
compilation)?

	Bernd
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