Date: Mon, 24 May 2010 16:50:31 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Neil Brown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>,
        Chuck Lever <chuck.lever@oracle.com>, linux-nfs@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] VFS: fix recent breakage of FS_REVAL_DOT
Message-ID: <20100524155031.GQ31073@ZenIV.linux.org.uk>
References: <20100524165756.2cfa54c4@notabene.brown>
 <20100524115903.GP31073@ZenIV.linux.org.uk>
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On Mon, May 24, 2010 at 12:59:03PM +0100, Al Viro wrote:

> BTW, here's a question for nfs client folks: is it true that for any two
> pathnames on _client_ resolving to pairs (mnt1, dentry) and (mnt2, dentry)
> resp., nfs_devname(mnt1, dentry, ...) and nfs_devname(mnt2, dentry, ...)
> should yield the strings that do not differ past the ':' (i.e. that the
> only possible difference is going to be in spelling the server name)?

Actually, there's a related one: suppose we have two mounts from the same
server, with the same flags, etc., ending up sharing a dentry on client.
What will we get from GETATTR asking for fs_locations, in fs_root field?

Can an nfs4 server e.g. have /x/y being a symlink that resolves to /a/b and
allow mounting of both /x/y/c and /a/b/c?  Which path would it return to
client that has mounted both, walked to some referral point and called
nfs_do_refmount(), triggering nfs4_proc_fs_locations()?

Trond, Neil?