[CentOS] Cryptographic Filesystem

Fri Feb 2 08:00:27 UTC 2007
Rodrigo Barbosa <rodrigob at darkover.org>

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On Fri, Feb 02, 2007 at 05:04:53AM -0200, Rodrigo Barbosa wrote:
> > > I've got a complete lockdown on cfsd, and had to hardboot the
> > > machine. In both cases, I've lost nothing, and only the specific
> > > file I was copying, on the destination, was "lost" (partially copied).
> > > It gave me a VERY good impression of cfs' robustness.
> > 
> > That sounds Good. heh..
> 
> On the other hand, CFS is VERY succeptible to a nasty nfs related deadlock.
> The scenario is easy to imagine.
> 
> Say cfsd tried to write to the disk and has to wait. Then, you will get
> a nfs timeout. Since you have a nfs timeout, processed will stall.
> Since cfsd is stalled, you can't get out of the timeout.
> 
> I'm still trying to figure out the best way to solve this. Maybe multithreading
> cfsd, or maybe simply using O_NONBLOCK. If I can think of a good way to solve 
> this, I might be able to patch it. I'm not sure about the O_NONBLOCK solution.
> It is kind of basic, and someone would have though of it before is it was
> all it takes, I guess.
> 
> This condition is VERY easy to trigger for me, if I copy a file from
> to the crypted filesystem, and both (crypted and non-crypted) as located
> on an external USB disk I have here.

Ok, I'm giving up on CFS, at least for now. Since I already use fuse for
a lot of stuff (sshfs, obexfs and mysqlfs), I'm trying encfs now.

Will let you know how it turns out.

[]s

- -- 
Rodrigo Barbosa
"Quid quid Latine dictum sit, altum viditur"
"Be excellent to each other ..." - Bill & Ted (Wyld Stallyns)

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