From owner-freebsd-hackers@FreeBSD.ORG Tue Apr 17 21:28:55 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 764AD1065672; Tue, 17 Apr 2012 21:28:55 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from bigwig.baldwin.cx (bigknife-pt.tunnel.tserv9.chi1.ipv6.he.net [IPv6:2001:470:1f10:75::2]) by mx1.freebsd.org (Postfix) with ESMTP id 4AA078FC1B; Tue, 17 Apr 2012 21:28:55 +0000 (UTC) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id B323AB958; Tue, 17 Apr 2012 17:28:54 -0400 (EDT) From: John Baldwin To: Andriy Gapon Date: Tue, 17 Apr 2012 16:43:39 -0400 User-Agent: KMail/1.13.5 (FreeBSD/8.2-CBSD-20110714-p13; KDE/4.5.5; amd64; ; ) References: <4F8999D2.1080902@FreeBSD.org> <201204160956.21148.jhb@freebsd.org> <4F8DD0FB.7000907@FreeBSD.org> In-Reply-To: <4F8DD0FB.7000907@FreeBSD.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201204171643.39447.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Tue, 17 Apr 2012 17:28:54 -0400 (EDT) Cc: freebsd-fs@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: [review request] zfsboot/zfsloader: support accessing filesystems within a pool X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Apr 2012 21:28:55 -0000 On Tuesday, April 17, 2012 4:22:19 pm Andriy Gapon wrote: > on 16/04/2012 16:56 John Baldwin said the following: > > On Saturday, April 14, 2012 1:35:35 pm Andriy Gapon wrote: > >> on 14/04/2012 18:37 Andriy Gapon said the following: > >>> > >>> I would like to ask for a review and/or testing of the following three patches: > >>> http://people.freebsd.org/~avg/zfsboot.patches.diff > >>> > >>> These patches add support for booting from an arbitrary filesystem of any > >>> detected ZFS pool. A filesystem could be selected in zfsboot and thus will > >>> affectfrom where zfsloader would be loaded. zfsboot passes information about > >>> the boot pool and filesystem to zfsloader, which uses those for loaddev and > >>> default value of currdev. A different pool+filesystem could be selected in > >>> zfsloader for booting kernel. Also if vfs.root.mountfrom is not explicitly set > >>> and is not derived from fstab, then it gets set to the selected boot filesystem. > >> > >> A note for prospective testers: the patched loader expect to be started by the > >> patched zfs boot as it passes an additional parameter for a filesystem guid. > >> I should probably add some way to distinguish between the older and newer zfs > >> boot blocks. Maybe an extra bit in bootflags? What do you think? > > > > An extra bit (similar to existing flags for detecting PXE and CD booting) > > sounds fine to me. (Note, I'm only replying to the question, have not looked > > at patches yet). > > I hope that you will :-) > > We already have a flag for ZFS (KARGS_FLAGS_ZFS, 0x4). So the new flag could be > named something ZFS-specific (as silly as KARGS_FLAGS_ZFS2) or something more > general such as KARGS_FLAGS_32_BYTES meaning that the total size of arguments > area is 32 bytes (as opposed to 24 previously). Does KARGS_FLAGS_GUID work? -- John Baldwin