RE: nfsd vurlerability submit

From: "Frank Filz" <ffilzlnx@mindspring.com>
To: <hch@infradead.org>, "'Trond Myklebust'" <trondmy@hammerspace.com>
Cc: <pgoetz@math.utexas.edu>, <wangzhibei1999@gmail.com>,
	<chuck.lever@oracle.com>, <greg@kroah.com>, <w@1wt.eu>,
	<security@kernel.org>, <bfields@fieldses.org>,
	<linux-nfs@vger.kernel.org>
Subject: RE: nfsd vurlerability submit
Date: Wed, 13 Jan 2021 07:45:34 -0800	[thread overview]
Message-ID: <05d301d6e9c3$228bcc50$67a364f0$@mindspring.com> (raw)
In-Reply-To: <20210113153013.GA1527598@infradead.org>

> On Wed, Jan 13, 2021 at 03:16:52PM +0000, Trond Myklebust wrote:
> > How would that work then? Would you just look at the project ID of the
> > directory identified by the filehandle as the export point, and then
> > match to the project ID on the target inode? That sounds like it
> > doesn't even need to encode anything special in the filehandle.
> 
> True, we would not even have to encode them.
> 
> > How do you set a project ID in XFS?
> 
> With the XFS_IOC_SETXFLAGS ioctl.
> 
> On the command line side people usually do it using the xfs_quota tool as
part
> of setting up the tree quotas, but it can also be done separately using
the chproj
> subcommand of xfs_io.

Is this also queried via the ioctl? If this is a viable way of specifying
sub-trees, nfs-ganesha could also use it, though making an ioctl call for
each file system object would add some metadata performance hit.

Frank