To: linux-nfs@vger.kernel.org
From: Richard Yao <ryao@gentoo.org>
Subject: Making an interface for alternative data streams
Cc: linux-fsdevel@vger.kernel.org
Message-ID: <56F03945.40208@gentoo.org>
Date: Mon, 21 Mar 2016 14:11:17 -0400
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I am thinking of implementing Solaris-style alternative data streams in
the ZFSOnLinux driver via an ioctl and writing a compatibility shim so
that software written to use O_XATTR can be trivially adapted to use the
interface.

I sketched out the fine details on github:

https://github.com/zfsonlinux/zfs/issues/4437

I would be much happier if the VFS gave filesystem drivers the ability
to implement O_XATTR. That would avoid the need to (ab)use an ioctl for
this and eliminate the risk of using a bit that would be defined to mean
something else. The former risks permissions checks becoming stale while
the latter is a situation that I would be happy to avoid.

Since this sort of interface is applicable to NFS too, I wanted to ask
what various mainline developers think about it before I tried doing an
initial implementation.


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