From: jtk@us.ibm.com (John T. Kohl)
To: Josef Sipek <jsipek@fsl.cs.sunysb.edu>, linux-fsdevel@vger.kernel.org
Subject: Re: Wrapper fs Code (wrapfs)
Date: 07 Aug 2006 16:35:23 -0400 [thread overview]
Message-ID: <6coduw708k.fsf@sumu.lexma.ibm.com> (raw)
In-Reply-To: <20060804205715.GA18719@filer.fsl.cs.sunysb.edu>
>>>>> "Josef" == Josef Sipek <jsipek@fsl.cs.sunysb.edu> writes:
Josef> That is an artifact of how the Linux VFS works. When you modify a
Josef> file though wrapfs (or any other stackable file system) the
Josef> wrapfs code gets called. It then calls the lower file system code
Josef> on your behalf. When you modify the lower file directly, ext3
Josef> gets the called, but since Linux has no way for this change to be
Josef> announced up the stack, wrapfs happily uses the old, cached
Josef> data. If you have ideas about how to solve this, please share
Josef> them - right now, there is a lot of work being done to get
Josef> Unionfs (ours) and eCryptfs into the vanilla linux kernel.
While constructed for a vnode system, the ideas in a set of
Ficus-related papers and theses could be helpful here. This is John
Heidemann's PhD thesis on the topic (covers necessary VM designs,
callbacks, etc.):
http://www.isi.edu/people/johnh/PAPERS/Heidemann95e.html
--
John Kohl
Senior Software Engineer - Rational Software - IBM Software Group
Lexington, Massachusetts, USA
jtk@us.ibm.com
<http://www.ibm.com/software/rational/>
next prev parent reply other threads:[~2006-08-07 20:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-04 6:09 Wrapper fs Code (wrapfs) UZAIR LAKHANI
2006-08-04 20:57 ` Josef Sipek
2006-08-07 4:50 ` UZAIR LAKHANI
2006-08-07 6:59 ` Josef Sipek
2006-08-08 7:57 ` UZAIR LAKHANI
2006-08-08 15:41 ` Josef Sipek
2006-08-09 10:53 ` UZAIR LAKHANI
2006-08-07 20:35 ` John T. Kohl [this message]
2006-08-07 21:24 ` Josef Sipek
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