Date: Tue, 17 Apr 2012 16:43:39 -0400 From: John Baldwin <jhb@freebsd.org> To: Andriy Gapon <avg@freebsd.org> Cc: freebsd-fs@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: [review request] zfsboot/zfsloader: support accessing filesystems within a pool Message-ID: <201204171643.39447.jhb@freebsd.org> In-Reply-To: <4F8DD0FB.7000907@FreeBSD.org> References: <4F8999D2.1080902@FreeBSD.org> <201204160956.21148.jhb@freebsd.org> <4F8DD0FB.7000907@FreeBSD.org>
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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
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