Date: Thu, 12 Sep 2002 21:56:44 -0700 From: Alfred Perlstein <bright@mu.org> To: Nate Lawson <nate@root.org> Cc: Bruce Evans <bde@zeta.org.au>, phk@FreeBSD.ORG, des@FreeBSD.ORG, arch@FreeBSD.ORG Subject: Re: PATCH: vnode->v_tag to const char * Message-ID: <20020913045644.GM21806@elvis.mu.org> In-Reply-To: <Pine.BSF.4.21.0209121745430.25388-100000@root.org> References: <20020912211025.GJ21806@elvis.mu.org> <Pine.BSF.4.21.0209121745430.25388-100000@root.org>
next in thread | previous in thread | raw e-mail | index | archive | help
* Nate Lawson <nate@root.org> [020912 17:58] wrote:
> On Thu, 12 Sep 2002, Alfred Perlstein wrote:
> >
> > Wouldn't most of the 'nfs' specific hacks be applicable to other remote
> > fs's? So then why not just a 'nfslike' flag where it is needed?
>
> I tend to agree although this may end up as a big discussion. I already
> have added VV_UNSAFE which is a propagation of PFS_PROCDEP (i.e. a
> kernel-mapped filesystem like procfs). I guess some filesystem groups
> might be:
>
> VV_NATIVE - ufs, ffs, mfs (full owner, ugid/flags support)
> VV_FOREIGN - msdosfs, ntfs, hpfs (don't support full unix semantics)
> VV_REMOTE - smbfs, nwfs (network-based)
> VV_KERNEL - procfs, fdescfs, devfs (view into kernel data)
> VV_WEIRD - unionfs ;-)
>
> Anyway, I'm not the right person for this but if perhaps you could come up
> with a list of the special cases in the VFS code that require certain
> semantics, we could check for capabilities instead of relying on the fs
> type.
>
> For instance, NFS would do this:
> getnewvnode("nfs",... VV_REMOTE | VV_NATIVE)
>
> And then vm/vm_swap could then just do
> if ((vp->v_vflag & VV_REMOTE) != 0)
> ...
>
> In looking through the use of v_tag, all people seemed to care about was
> VV_REMOTE and VV_KERNEL (as defined above) so perhaps that's all we need.
It seems like you've put quite a bit more thought into this than I have,
why not just take a bit of time to see how well your proposal maps to
what we have, then do a quick drive-by commit, no one will complain. ;)
--
-Alfred Perlstein [alfred@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
start asking why software is ignoring 30 years of accumulated wisdom.'
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-arch" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020913045644.GM21806>