From owner-freebsd-hackers@FreeBSD.ORG Tue Apr 17 20:22:30 2012 Return-Path: Delivered-To: freebsd-hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 575B8106566B; Tue, 17 Apr 2012 20:22:30 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id 3FA208FC1B; Tue, 17 Apr 2012 20:22:29 +0000 (UTC) Received: from porto.starpoint.kiev.ua (porto-e.starpoint.kiev.ua [212.40.38.100]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id XAA01638; Tue, 17 Apr 2012 23:22:21 +0300 (EEST) (envelope-from avg@FreeBSD.org) Received: from localhost ([127.0.0.1]) by porto.starpoint.kiev.ua with esmtp (Exim 4.34 (FreeBSD)) id 1SKEur-000IdG-1A; Tue, 17 Apr 2012 23:22:21 +0300 Message-ID: <4F8DD0FB.7000907@FreeBSD.org> Date: Tue, 17 Apr 2012 23:22:19 +0300 From: Andriy Gapon User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:10.0.3) Gecko/20120317 Thunderbird/10.0.3 MIME-Version: 1.0 To: John Baldwin References: <4F8999D2.1080902@FreeBSD.org> <4F89B567.6090008@FreeBSD.org> <201204160956.21148.jhb@freebsd.org> In-Reply-To: <201204160956.21148.jhb@freebsd.org> X-Enigmail-Version: 1.4 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit 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 20:22:30 -0000 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). -- Andriy Gapon