From owner-freebsd-hackers  Sat Sep  8 13: 6:34 2001
Delivered-To: freebsd-hackers@freebsd.org
Received: from holly.calldei.com (adsl-208-191-149-190.dsl.hstntx.swbell.net [208.191.149.190])
	by hub.freebsd.org (Postfix) with ESMTP
	id C6AAD37B405; Sat,  8 Sep 2001 13:06:28 -0700 (PDT)
Received: (from chris@localhost)
	by holly.calldei.com (8.11.4/8.9.3) id f88K6Mr06088;
	Sat, 8 Sep 2001 15:06:22 -0500 (CDT)
	(envelope-from chris)
Date: Sat, 8 Sep 2001 15:06:21 -0500
From: Chris Costello <chris@calldei.com>
To: Maxim Sobolev <sobomax@FreeBSD.org>
Cc: phk@critter.freebsd.dk, brent@rcfile.org, current@FreeBSD.org,
	hackers@FreeBSD.org
Subject: Re: Junior Kernel Hacker task: improve vnode->v_tag
Message-ID: <20010908150620.F548@holly.calldei.com>
Reply-To: chris@calldei.com
References: <20010908030110.E548@holly.calldei.com> <200109081154.OAA95138@www.abc.com.ua>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.2.5i
In-Reply-To: <200109081154.OAA95138@www.abc.com.ua>; from sobomax@FreeBSD.org on Sat, Sep 08, 2001 at 02:54:38PM +0300
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-hackers.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-hackers>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-hackers>
X-Loop: FreeBSD.ORG

On Saturday, September 08, 2001, Maxim Sobolev wrote:
> I don't like idea to hardcode the same string ("procfs"), with the
> same meaning in several places across kernel. As for your proposition
> to use f_fstypename to set v_tag, it is even more bogus because
> value of the f_fstypename is supplied from the user level, so
> potentially it could be anything and we can't make any reasonable
> assumptions about mapping between its value and type of the filesystem
> in question. 

   How do you figure?  The contents if `f_fstypename' must match
a configured file system exactly, so it could _not_ be anything.
To quote sys/kern/vfs_syscalls.c:mount():

        if ((error = copyinstr(SCARG(uap, type), fstypename, MFSNAMELEN, NULL))
                vput(vp);
                return (error);
        }
        for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
                if (!strcmp(vfsp->vfc_name, fstypename))
                        break;
        if (vfsp == NULL) {
                /* ... try and load a module ... */
                /* ... fail if no module can be found, or no
                 * matching VFS is loaded */
        }

-- 
+-------------------+---------------------------------------------------+
| Chris Costello    | You depend too much on computers for information. |
| chris@calldei.com |                                                   |
+-------------------+---------------------------------------------------+

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message