Hi.
I had a look at how to implement this, and came up with the attached
patch. It is able to set up btrfs, but the resulting image do not
boot. I do not understand why, so I thought it was time to ask for
feedback. :)
--
Happy hacking
Petter Reinholdtsen
diff --git a/vmdebootstrap b/vmdebootstrap
index a6d43ac..6eb6d37 100755
--- a/vmdebootstrap
+++ b/vmdebootstrap
@@ -36,6 +36,9 @@ class VmDebootstrap(cliapp.Application):
self.settings.boolean(['verbose'], 'report what is going on')
self.settings.string(['image'], 'put created disk image in FILE',
metavar='FILE')
+ self.settings.string(['roottype'],
+ 'specify file system type for /',
+ default='ext4')
self.settings.bytesize(['size'],
'create a disk image of size SIZE (%default)',
metavar='SIZE',
@@ -110,7 +113,8 @@ class VmDebootstrap(cliapp.Application):
try:
rootdev = None
- roottype = 'ext4'
+ self.settings['roottype'] = 'btrfs'
+ roottype = self.settings['roottype']
bootdev = None
boottype = None
if self.settings['image']:
@@ -120,6 +124,13 @@ class VmDebootstrap(cliapp.Application):
(rootdev,bootdev) = self.setup_kpartx()
self.mkfs(rootdev, type=roottype)
rootdir = self.mount(rootdev)
+ rootfsdir = rootdir
+ if 'btrfs' == roottype:
+ # Put root in a subvolume, to ease snapshots and volume
management
+ newrootdir = "%s/@" % rootdir
+ self.runcmd(['btrfs', 'subvolume', 'create', newrootdir])
+ os.mkdir("%s/btrfs" % newrootdir)
+ rootdir = newrootdir
if bootdev:
if self.settings['boottype']:
boottype = self.settings['boottype']
@@ -143,7 +154,7 @@ class VmDebootstrap(cliapp.Application):
self.customize(rootdir)
if self.settings['image']:
if not self.settings['no-extlinux']:
- self.install_extlinux(rootdev, rootdir)
+ self.install_extlinux(rootdev, rootdir, rootfsdir)
self.optimize_image(rootdir)
if self.settings['foreign']:
@@ -315,7 +326,11 @@ class VmDebootstrap(cliapp.Application):
fstab = os.path.join(rootdir, 'etc', 'fstab')
with open(fstab, 'w') as f:
f.write('proc /proc proc defaults 0 0\n')
- f.write('%s / %s errors=remount-ro 0 1\n' % (rootdevstr, roottype))
+ if 'btrfs' == roottype:
+ f.write('%s / %s subvol=@,errors=remount-ro 0 1\n' %
(rootdevstr, roottype))
+ f.write('%s /btrfs %s errors=remount-ro 0 1\n' % (rootdevstr,
roottype))
+ else:
+ f.write('%s / %s errors=remount-ro 0 1\n' % (rootdevstr,
roottype))
if bootdevstr:
f.write('%s /boot %s errors=remount-ro 0 2\n' % (bootdevstr,
boottype))
@@ -400,7 +415,7 @@ class VmDebootstrap(cliapp.Application):
f.close()
- def install_extlinux(self, rootdev, rootdir):
+ def install_extlinux(self, rootdev, rootdir, rootfsdir):
self.message('Installing extlinux')
def find(pattern):
@@ -419,7 +434,7 @@ class VmDebootstrap(cliapp.Application):
'-s', 'UUID', rootdev])
uuid = out.splitlines()[0].strip()
- conf = os.path.join(rootdir, 'extlinux.conf')
+ conf = os.path.join(rootfsdir, 'extlinux.conf')
logging.debug('configure extlinux %s' % conf)
f = open(conf, 'w')
f.write('''
@@ -428,7 +443,7 @@ timeout 1
label linux
kernel %(kernel)s
-append initrd=%(initrd)s root=UUID=%(uuid)s ro %(kserial)s
+append initrd=%(initrd)s root=UUID=%(uuid)s ro %(kserial)s %(rootflags)s
%(extserial)s
''' % {
'kernel': kernel_image,
@@ -437,6 +452,7 @@ append initrd=%(initrd)s root=UUID=%(uuid)s ro %(kserial)s
'kserial':
'console=ttyS0,115200' if self.settings['serial-console'] else '',
'extserial': 'serial 0 115200' if self.settings['serial-console'] else '',
+ 'rootflags': 'rootflags=subvol=@' if 'btrfs' == self.settings['roottype']
else '',
})
f.close()
@@ -447,7 +463,7 @@ append initrd=%(initrd)s root=UUID=%(uuid)s ro %(kserial)s
with open(inittab, 'a') as f:
f.write('\nS0:23:respawn:%s\n' % serial_command)
- self.runcmd(['extlinux', '--install', rootdir])
+ self.runcmd(['extlinux', '--install', rootfsdir])
self.runcmd(['sync'])
import time; time.sleep(2)
