From owner-freebsd-current@FreeBSD.ORG Mon Aug 23 14:02:32 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A72571065672 for ; Mon, 23 Aug 2010 14:02:32 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 0B0B28FC13 for ; Mon, 23 Aug 2010 14:02:31 +0000 (UTC) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id o7NE1n5O074940 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 23 Aug 2010 17:01:49 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4) with ESMTP id o7NE1neb016314; Mon, 23 Aug 2010 17:01:49 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4/Submit) id o7NE1na6016313; Mon, 23 Aug 2010 17:01:49 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Mon, 23 Aug 2010 17:01:49 +0300 From: Kostik Belousov To: Ed Schouten Message-ID: <20100823140149.GG2396@deviant.kiev.zoral.com.ua> References: <201008230826.49509.jhb@freebsd.org> <20100823132551.GE2396@deviant.kiev.zoral.com.ua> <20100823133555.GA64651@hoeg.nl> <20100823134459.GF2396@deviant.kiev.zoral.com.ua> <20100823134723.GC64651@hoeg.nl> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="7hK5U8dVDlZxii7z" Content-Disposition: inline In-Reply-To: <20100823134723.GC64651@hoeg.nl> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean Cc: Ian FREISLICH , freebsd-current@freebsd.org Subject: Re: fusefs-kmod broken? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Aug 2010 14:02:32 -0000 --7hK5U8dVDlZxii7z Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Aug 23, 2010 at 03:47:23PM +0200, Ed Schouten wrote: > * Kostik Belousov wrote: > > On Mon, Aug 23, 2010 at 03:35:55PM +0200, Ed Schouten wrote: > > > * Kostik Belousov wrote: > > > > Which most likely means that fusesfs filled its own struct fileops > > > > without properly initializing fo_truncate member. > > >=20 > > > It's a bit misleading that cdevs automatically patch the table, while > > > the fileops don't. Maybe it would be a good idea to patch finit() to > > I do not understand your first sentence. Would you please elaborate ? >=20 > Say, you create a cdev, if you don't implement all ops, it will check > for null pointers and return error codes accordingly. This doesn't > happen for fileops, which is probably one of the reasons why people > sometimes forget to implement them. >=20 > Wouldn't it be better to prevent this form of footshooting by adding > assertions? This will add some overhead for any file descriptor created, > but a kernel with INVARIANTS isn't meant to be fast. Thanks, I see it now. The cdev interface definitely falls into the public kernel interface. Having to fill all cdevsw methods for a random driver is too much burden put on the several dozens maintainers. On the other hand, file level is not much widely used by third-party components, and even in-tree code implements only ten different file types. I would not object loudly if someone put such checks as proposed under INVARIANTS, but also I do not see a real point in having them. Might be slightly better to put the checks, again under INVARIANTS, in the fo_XXX() wrappers. --7hK5U8dVDlZxii7z Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkxyf0wACgkQC3+MBN1Mb4gjkACfWQSnkIDLXKiZECPd0x38vUpv IpwAnAqH9sGw8rGNp4eg4ud0SUBLgreK =ftxV -----END PGP SIGNATURE----- --7hK5U8dVDlZxii7z--