def shrink(self, silent=False):
"""Shrink the image.
This is accomplished by shrinking the last file system of the
image and then updating the partition table. The shrinked device is
returned.
ATTENTION: make sure umount is called before shrink
"""
def get_fstype(partition):
"""Get file system type"""
device = "%s%d" % (self.guestfs_device, partition['part_num'])
return self.g.vfs_type(device)
def is_extended(partition):
"""Returns True if the partition is an extended partition"""
if self.meta['PARTITION_TABLE'] == 'msdos':
mbr_id = self.g.part_get_mbr_id(self.guestfs_device,
partition['part_num'])
return mbr_id in (0x5, 0xf)
return False
def part_del(partnum):
"""Delete a partition"""
self.g.part_del(self.guestfs_device, partnum)
MB = 2**20
if self.is_unsupported():
if not silent:
self.out.warn("Shrinking is disabled for unsupported images")
return None
sector_size = self.g.blockdev_getss(self.guestfs_device)
last_part = None
fstype = None
while True:
last_part = self._last_partition()
fstype = get_fstype(last_part)
if fstype == 'swap':
self.meta['SWAP'] = "%d:%s" % \
(last_part['part_num'],
(last_part['part_size'] + MB - 1) // MB)
part_del(last_part['part_num'])
continue
elif is_extended(last_part):
part_del(last_part['part_num'])
continue
# Most disk manipulation programs leave 2048 sectors after the last
# partition
new_size = last_part['part_end'] + 1 + 2048 * sector_size
self.size = min(self.size, new_size)
break
if not fstype:
if not silent:
self.out.warn("Unable to shrink partition: %s. Reason: "
"Could not detect file system." %
last_part['part_num'])
return None
if not re.match("ext[234]", fstype):
if not silent:
self.out.warn("Unable to shrink partition: %s. Reason: "
"Don't know how to shrink %s file systems." %
(last_part['part_num'], fstype))
return None
part_dev = "%s%d" % (self.guestfs_device, last_part['part_num'])
out = self.g.tune2fs_l(part_dev)
block_size = int(filter(lambda x: x[0] == 'Block size', out)[0][1])
old_block_cnt = int(filter(lambda x: x[0] == 'Block count', out)[0][1])
try:
if self.check_guestfs_version(1, 15, 17) >= 0:
self.g.e2fsck(part_dev, forceall=1)
else:
self.g.e2fsck_f(part_dev)
except RuntimeError as e:
# There is a bug in some versions of libguestfs and a RuntimeError
# is thrown although the command has successfully corrected the
# found file system errors.
if str(e).find('***** FILE SYSTEM WAS MODIFIED *****') == -1:
raise
self.g.resize2fs_M(part_dev)
out = self.g.tune2fs_l(part_dev)
assert block_size == \
int(filter(lambda x: x[0] == 'Block size', out)[0][1])
block_cnt = int(filter(lambda x: x[0] == 'Block count', out)[0][1])
# Add some extra space for the image to be able to run.
block_cnt = min(old_block_cnt, block_cnt + 8388608 / block_size)
start = last_part['part_start'] / sector_size
end = start + (block_size * block_cnt) / sector_size - 1
self._resize_partition(end)
# Enlarge the underlying file system to consume the available space
self.g.resize2fs(part_dev)
new_size = (end + 1) * sector_size
assert new_size <= self.size
if self.meta['PARTITION_TABLE'] == 'gpt':
with self.raw_device(readonly=False) as raw:
ptable = GPTPartitionTable(raw)
self.size = ptable.shrink(new_size, self.size)
else:
self.size = min(new_size + 2048 * sector_size, self.size)
if not silent:
self.out.success("Image size is %dMB" %
((self.size + MB - 1) // MB))
return part_dev
