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Date:      Tue, 28 Jan 2014 09:48:27 +0100
From:      Nick Hibma <nick@van-laarhoven.org>
To:        Arrigo Marchiori <ardovm@yahoo.it>
Cc:        Ian Smith <smithi@nimnet.asn.au>, =?windows-1252?Q?=93FreeBSD_Embedded_Mailing_List=94?= <freebsd-embedded@freebsd.org>
Subject:   Re: Creating code slice before disk image in nanobsd
Message-ID:  <69B43B44-C122-4D6E-92AB-7A5480ABFE54@van-laarhoven.org>
In-Reply-To: <20140123120053.GC27181@snail.casa>
References:  <20120629133759.GA19373@snail.casa> <20140114161533.GB19601@snail.casa> <CAJ-VmonKFEvPRimEmA8vnAbXVCYQ16yOftYhq03VJBYB5knotA@mail.gmail.com> <6027B660-1D2E-4058-B87F-83D8225F0DC3@bsdimp.com> <20140116034220.B43023@sola.nimnet.asn.au> <alpine.BSF.2.00.1401151214480.83038@wonkity.com> <20140123120053.GC27181@snail.casa>
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>>>> I'll take a look at things... It isn't obvious at first blush this =
is
>>>> the right thing to do, but I need to think about it a bit...
>>>>=20
>>>> Warner
>>>=20
>>> Perhaps an aside, but I'm pretty sure Warren (cc'd) has said that =
gpart
>>> can do anything that fdisk AND bsdlabel can do?
>>=20
>> Yes.  Although there is an exception: gpart silently forces alignment =
to=20
>> CHS values on MBR slices, and fdisk does not.  So to get a 4K-aligned=20=

>> slice requires fdisk.  gpart can align BSD partitions inside a slice =
to=20
>> 4K, but that is a workaround.  (I believe gpart should default to CHS=20=

>> but use -a alignment or -b values when given for MBR slices, =
regardless=20
>> of the MBR spec.  This becomes increasingly important as 4K drives =
and=20
>> SSDs become more common.)
>=20
> I didn't take alignment into account; I just adapted the calculations
> to match the parameters required by gpart.
>=20
>>> If that's so, and the
>>> object here is to deprecate fdisk, why not also replace these lines:
>>>=20
>>> +
>>> +	bsdlabel -w -B -b ${NANO_WORLDDIR}/boot/boot ${MD}
>>> +	bsdlabel ${MD}
>>> +
>>>=20
>>> with their gpart equivalents?
>>>=20
>>> (and no, I don't know what those should be in this context)
>>=20
>> To create the initial MBR, probably already done before the code =
above:
>>   gpart create -s mbr ${MD}
>=20
> This is done by the patch.
>=20
> [...]
>> To create a slice and set it active:
>>   gpart add -s freebsd ${MD}    [1]
> [...]
>> [1] when creating the slice, -a4k or -b1m can be specified but will =
be
>>     silently rounded to CHS values
>=20
> The -b parameter is also used, therefore your note [1] applies.
>=20
>>   gpart set -a active -i1 ${MD}
>=20
> This is done by the patch.
>=20
>> To create the BSDlabel inside the slice and write the bootcode to it:
>>   gpart create -s bsd ${MD}s1
>>   gpart bootcode -b ${NANO_WORLDDIR}/boot/boot ${MD}s1
>> Then BSD partitions can be added with, for example:
>>   gpart add -t freebsd-ufs -s2g ${MD}s1  [2]
> [...]
>> [2] when creating BSD partitions, -a4k can be used and they will be
>>     created with an offset inside the slice to end up aligned
>=20
> These were kept as the original:
>=20
> bsdlabel -w -B -b ${NANO_WORLDDIR}/boot/boot ${MD}s1
>=20
>> For reference, see=20
>> =
http://www.wonkity.com/~wblock/docs/html/disksetup.html#_the_old_standard_=
mbr

For reference, I=92ve replaced the disk image build with a simpler disk =
image function, and a separate script to generate a full disk image =
(used only for new installations. The disk image script is a =
simplification of the existing one in nanobsd.sh.

The second, separate script does the full initialisation of a disk =
depending on what it finds. It also does automatic filling of the disk =
with a /data partition (so we can use 2 150MB code partitions, cfg =
partition and the rest for storage on any medium). As you can see we =
still use the boot0cfg commands here. It can build an MBR style =
partitioning, but also a BSD style partitioning (USB drives) (left out =
for brevity).

(Note: Our scripts can not only generate MBR style partitioning, but =
also BSD style partitioning holding 2 code slices. For that to work you =
will need to do some fancy twiddling of the partition switching after =
update).

Maybe this is of use for reference in this discussions.

Nick



echo "### Creating MBR style layout for HD/CF style image on $CFCARD" =
1>&4
# AWIMGroot1    ada0s1a
# AWIMGroot2    ada0s2a
# AWIMGcfg      ada0s3
# AWIMGdata     ada0s4
gpart create -s MBR $CFCARD

# We need to increase the size of the root partitions by a small amount =
to
# make room for the BSD label at the start
gpart add -t freebsd -s $(($IMAGE_CODESIZE+1))M $CFCARD
gpart create -s BSD ${CFCARD}s1
gpart bootcode -b $NANO_WORLDDIR/boot/boot ${CFCARD}s1
gpart add -i 1 -t freebsd-ufs -s ${IMAGE_CODESIZE}M ${CFCARD}s1
root1=3D${CFCARD}s1a

if [ $NANO_IMAGES -gt 1 ]; then
        gpart add -i 2 -t freebsd -s $(($IMAGE_CODESIZE+1))M $CFCARD
        gpart create -s BSD ${CFCARD}s2
        gpart bootcode -b $NANO_WORLDDIR/boot/boot ${CFCARD}s2
        gpart add -t freebsd-ufs -s ${IMAGE_CODESIZE}M ${CFCARD}s2
        root2=3D${CFCARD}s2a
fi

gpart add -i 3 -t freebsd -s ${IMAGE_CFGSIZE}M $CFCARD
cfgpart=3D${CFCARD}s3
if [ -z "$IMAGE_DATASIZE" ] || [ "$IMAGE_DATASIZE" -gt 0 ]; then
        gpart add -i 4 -t freebsd ${IMAGE_DATASIZE:+-s =
${IMAGE_DATASIZE}M} $CFCARD
        datapart=3D${CFCARD}s4
fi

# Mark the first partition bootable
gpart bootcode -b $NANO_WORLDDIR/$NANO_BOOTLOADER $CFCARD
gpart set -a active -i 1 $CFCARD
# Configure boot0
boot0cfg $NANO_BOOT0CFG $CFCARD

echo "### Populating root 1 partition" 1>&4
dd if=3D$IMG of=3D/dev/$root1 bs=3D8k skip=3D1 seek=3D1

if [ -n "$root2" ]; then
        echo "### Leaving empty root 2 partition" 1>&4
        echo "### Populating config partition" 1>&4
fi

newfs -L ${NANO_LABEL}cfg $cfgpart
populate_fs /dev/$cfgpart ./Cfg ${IMAGE_SUBNAME:+./$IMAGE_SUBNAME/Cfg} =
$cfgdir

if [ -n "$datapart" ]; then
        echo "### Populating data partition" 1>&4
        newfs -L ${NANO_LABEL}data $datapart
        populate_fs /dev/$datapart ${IMAGE_DEFAULTS}/Data ./Data =
${IMAGE_SUBNAME:+./$IMAGE_SUBNAME/Data}
fi



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