From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Fri, 23 Dec 2016 15:00:37 +0100 Subject: [Buildroot] [PATCH 1/2] first_boot_rootfs_resizer: New Package. In-Reply-To: References: <20161202101028.26736-1-daggs@gmx.com> <20161217165039.6169d54c@free-electrons.com> Message-ID: <20161223150037.5dff81d0@free-electrons.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hello, On Fri, 23 Dec 2016 14:41:59 +0100, daggs wrote: > > We clearly shouldn't have an "unclear" license for such a package. > the file is ported from the odroidc2 buildroot, I've marked it unclear because it doesn't states it's license anywhere. Would be good to get a clarified license, especially when the source code is inside Buildroot itself. > > > +ROOT=$(cat /proc/cmdline | tr ' ' '\n' | grep root= | cut -f 2 -d =) > > > > This will fail badly if you have a GPT partition table and root= is > > using the partition UUID, like: > > > > root=UUID=xyz > > > I see, that should be the proper way to detect the rootfs file system? One way would be to use the Busybox "rdev" applet, but it's not enabled in our default configuration. You could run "stat /" where the "Device" fields tells you the block device that was mounted as the root filesystem. But not that trivial to go from this (major/minor) to the actual /dev/. I'm not sure there's a good and simple way to achieve that I'm afraid. > > > +DEV=$(echo ${ROOT} | sed 's/p[0-9]\+$//g') > > > > This only works for mmcblkXpY case, but not for sdXY > correct, will see how I can generalize it more. It's actually not that easy to generalize, except of course if you restrict yourself to sdXY and mmcblkXpY. > > > +if [ -f /.first_boot ]; then > > > + echo "Resizing fs, please wait... upon finish the system will be restarted" > > > + # ok, its the very first boot, we need to resize the disk. > > > + p2_start=`fdisk -l ${DEV} | grep ${PART} | awk '{print $2}'` > > > + p2_finish=`fdisk -l ${DEV} | grep sectors | awk '{printf $5}'` > > > > This will not work with the Busybox fdisk, which is the default in > > Buildroot: > > > > Disk /dev/sda: 256.0 GB, 256060514304 bytes > > 255 heads, 63 sectors/track, 31130 cylinders > > Units = cylinders of 16065 * 512 = 8225280 bytes > > > > Device Boot Start End Blocks Id System > > /dev/sda1 * 1 3648 29295616 83 Linux > > /dev/sda2 3648 4644 8000512 82 Linux swap > > /dev/sda3 4644 31131 212761600 83 Linux > I'm pretty sure I've tested it with busybox's fdisk. Well, to find the size of the block device, you grep for "sectors". The only line matching with Busybox fdisk is: 255 heads, 63 sectors/track, 31130 cylinders Which doesn't contain the size (at least not the size in sectors) > > Using sfdisk is probably more appropriate here, as it's meant to be > > used for scripting. > ok, will check. But sfdisk is not in Busybox, so make sure to select the right package. > > Also, this logic doesn't work if the root filesystem is mounted > > read-only, since you expect to be able to remove .first_boot, and > > remove the script itself. > so essentally, if the fs is read only, there is no way to remove it. > so the right way is to check every boot if the fs is maxed out to the boot dev and resize it if not. > am I correct? Well, what if you're read-only but the root filesystem doesn't take the whole space? Perhaps you can check in 'mount | grep " / "' whether it's mounted read-only or not? > > Why wouldn't the S00resizefs script directly do the resizing work? > as said above, I've ported it from the odroidc2 buildroot, so I didn't tried to change it too much. Since the source code is part of Buildroot and we don't intend to resync with the odroidc2 stuff, please make it more Buildroot-ish. Thanks a lot! Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com