Re: [PATCH] 9pfs: Add FreeBSD support

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Jul 30, 2025 at 10:32:22AM -0400, Mark Johnston wrote:
> On Tue, Jul 29, 2025 at 06:09:35PM +0200, Christian Schoenebeck wrote:
> > On Wednesday, July 23, 2025 5:55:58 PM CEST Mark Johnston wrote:
> > > This is largely derived from existing Darwin support.  FreeBSD
> > > apparently has better support for *at() system calls so doesn't require
> > > workarounds for a missing mknodat().  The implementation has a couple of
> > > warts however:
> > > - The extattr(2) system calls don't support anything akin to
> > >   XATTR_CREATE or XATTR_REPLACE, so a racy workaround is implemented.
> > > - Attribute names cannot begin with "user." on ZFS, so the prefix is
> > >   trimmed off.  FreeBSD's extattr system calls sport an extra
> > >   "namespace" identifier, and attributes created by the 9pfs backend
> > >   live in the universal user namespace, so this seems innocent enough.
> > > 
> > > The 9pfs tests were verified to pass on the UFS, ZFS and tmpfs
> > > filesystems.
> > > 
> > > Signed-off-by: Mark Johnston <markj@FreeBSD.org>
> > 
> > Hi Mark,
> > 
> > first off, the problem is I currently don't have a FreeBSD host to test and
> > won't have the time in near future neither.
> > 
> > So what was your general intention regarding this patch, fire and forget, or
> > would you be around for issues/patches regarding 9pfs FreeBSD support?
> 
> Thank you for taking a look.
> 
> I'll certainly be around to help deal with issues and patches relating
> to 9pfs+FreeBSD hosts.  It's hard to prove that, but for what it's worth
> I use QEMU fairly extensively for FreeBSD development when I can't use
> the native hypervisor, and that's not likely to change anytime soon.
> 
> Would adding myself to MAINTAINERS for virtio-9pfs (or a new
> virtio-9pfs-freebsd category) be appropriate in that case?

> > > diff --git a/hw/9pfs/9p-util-freebsd.c b/hw/9pfs/9p-util-freebsd.c
> > > new file mode 100644
> > > index 0000000000..e649f79d4b
> > > --- /dev/null
> > > +++ b/hw/9pfs/9p-util-freebsd.c
> > > @@ -0,0 +1,124 @@
> > > +/*
> > > + * 9p utilities (FreeBSD Implementation)
> > > + *
> > > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > > + * See the COPYING file in the top-level directory.
> > > + */
> > 
> > I think for new source files in QEMU the policy is to use
> > SPDX-License-Identifier: ... now?
> 
> checkpatch.pl does complain about that, yes, but it also qualifies the
> warning with, "unless this file was copied from existing code already
> having such text."  I used 9p-util-darwin.c as a starting point for this
> file, so kept the existing license text.  I can certainly change it
> though.

In that case, this is fine as is.


With regards,
Daniel
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