Date: Thu, 01 Jan 2015 09:23:06 -0800 From: Nathan Whitehorn <nwhitehorn@freebsd.org> To: freebsd-current@freebsd.org Subject: Re: makefs && gpart (...) Message-ID: <54A5827A.3000406@freebsd.org> In-Reply-To: <20150101114829.GA3196@unixarea.DDR.dd> References: <20150101114829.GA3196@unixarea.DDR.dd>
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On 01/01/15 03:48, Matthias Apitz wrote:
>
> Hello,
>
> I have a small question and a small request re/ makefs && gpart:
>
> There is a script src/release/i386/make-memstick.sh to create an image
> from a full directory tree; the tree is result of
>
> make installworld DESTDIR=/tree
> make installkernel DESTDIR=/tree
>
> the script mainly does:
>
> ...
> makefs -B little -o label=FreeBSD_Install ${2} ${1}
> if [ $? -ne 0 ]; then
> echo "makefs failed"
> exit 1
> fi
> rm ${1}/etc/fstab
>
> unit=$(mdconfig -a -t vnode -f ${2})
> if [ $? -ne 0 ]; then
> echo "mdconfig failed"
> exit 1
> fi
> gpart create -s BSD ${unit}
> gpart bootcode -b ${1}/boot/boot ${unit}
> gpart add -t freebsd-ufs ${unit}
> mdconfig -d -u ${unit}
>
> As you can see, it does makefs first, and after this it creates the
> gpart structure in the image (i.e. in its memory file system).
> Why is this in this order and where exactly starts the file system
> created by makefs?
This is a quirk of BSD disklabels: the first partition can start at
address 0 and the first 16 sectors of UFS2 file systems are reserved for
the label headers. It's not portable to other partition schemes. For
-CURRENT, this script has been replaced, by the way, and doesn't use BSD
labels anymore.
-Nathan
>
> The request is: it would also be nice if 'make-memstick.sh' would allow
> to pass from the command line some values for the size of the file
> system to be created in the image; I modified it to fit my needs as:
>
> size=15482880b
> ...
> makefs -B little -M ${size} -m ${size} -f 400000 ....
>
> Thanks
>
> matthias
>
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