Date: Fri, 16 Oct 1998 22:17:14 -0700 From: Mike Smith <mike@smith.net.au> To: Bruce Evans <bde@zeta.org.au> Cc: mike@smith.net.au, shimon@simon-shapiro.org, freebsd-current@FreeBSD.ORG, jkh@time.cdrom.com Subject: Re: Show Stopper? Failure to Install 19981014 Message-ID: <199810170517.WAA00708@dingo.cdrom.com> In-Reply-To: Your message of "Sat, 17 Oct 1998 14:51:01 %2B1000." <199810170451.OAA00376@godzilla.zeta.org.au>
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> >It appears to be caused by not entering the root filesystem first.
> >There's a test in the disklabel code which checks to see if the
> >partition you have open to write the label starts at 0, and if not then
> >it defaults to the 'a' partition.
>
> Labels should always be written using the RAW_PART partition ('c' on
> i386's). If not, then they must be written using a partition that has
> offset 0. If not even that, then the 'a' partition must have offset 0.
> Unfortunately, newfs(8) writes labels to the same partition that it
> is newfs'ing.
I checked the history for this; it appears to have done this for a long
time.
There is also bogus code in sys/ufs/ufs/ufs_disksubr.c which checks the
start of the partition to which the label is being written, and if that
is not 0, uses partition 0 ('a') instead. It is this code which is
returning EXDEV.
> >Partitions are laid on disk in the order that you enter them. The 'a'
> >partition is always reserved for the partition you mount on /. If you
>
> It's not reserved. It's just the default.
It's reserved by sysinstall.
> >don't enter this partition first, it won't be at the beginning of the
> >disk, and any attempt to rewrite the disklabel will fail.
> >
> >Due to the way that sysinstall interacts with libdisk, this is
> >difficult to get "right". We probably need a bandaid which insists
> >that if you want to create an 'a' partition you must lay it down first.
>
> This is easy to fix by changing the (whole) test in writedisklabel() to
> `lp->p_partitions[RAW_PART] == 0'. Even that is probably only necessary
> to give the right errno (this condition is enforced in several places).
> This might wake bugs in other code where partition 0 is magic.
Exactly. More to the point, why has this symptom only just recently
manifested?
--
\\ Sometimes you're ahead, \\ Mike Smith
\\ sometimes you're behind. \\ mike@smith.net.au
\\ The race is long, and in the \\ msmith@freebsd.org
\\ end it's only with yourself. \\ msmith@cdrom.com
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