commit ce9283c15df390ebfd3e3dcdd5c57b13b3d258b4
Author: Thomas Thrainer <thomasth@google.com>
Date:   Tue Apr 23 14:04:22 2013 +0200

    Move lib/bdev.py to lib/block/bdev.py
    
    That's in preparation of extracting DRBD related code from bdev.py. As
    bdev.py is already rather long, new features will require to split it
    into more manageable pieces. That's why it's moved in an own directory.
    
    Signed-off-by: Thomas Thrainer <thomasth@google.com>
    Signed-off-by: Michele Tartara <mtartara@google.com>
    Reviewed-by: Michele Tartara <mtartara@google.com>

diff --git a/Makefile.am b/Makefile.am
index 34f8d8a..8f979c7 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -41,6 +41,7 @@ SHELL_ENV_INIT = autotools/shell-env-init
 # the directory + 'dir' suffix
 clientdir = $(pkgpythondir)/client
 hypervisordir = $(pkgpythondir)/hypervisor
+blockdir = $(pkgpythondir)/block
 httpdir = $(pkgpythondir)/http
 masterddir = $(pkgpythondir)/masterd
 confddir = $(pkgpythondir)/confd
@@ -108,6 +109,7 @@ DIRS = \
 	lib/confd \
 	lib/http \
 	lib/hypervisor \
+	lib/block \
 	lib/impexpd \
 	lib/masterd \
 	lib/rapi \
@@ -257,7 +259,6 @@ pkgpython_PYTHON = \
 	lib/__init__.py \
 	lib/asyncnotifier.py \
 	lib/backend.py \
-	lib/bdev.py \
 	lib/bootstrap.py \
 	lib/cli.py \
 	lib/cmdlib.py \
@@ -314,6 +315,10 @@ hypervisor_PYTHON = \
 	lib/hypervisor/hv_lxc.py \
 	lib/hypervisor/hv_xen.py
 
+block_PYTHON = \
+	lib/block/__init__.py \
+	lib/block/bdev.py
+
 rapi_PYTHON = \
 	lib/rapi/__init__.py \
 	lib/rapi/baserlib.py \
@@ -1112,7 +1117,7 @@ python_tests = \
 	test/py/ganeti.asyncnotifier_unittest.py \
 	test/py/ganeti.backend_unittest-runasroot.py \
 	test/py/ganeti.backend_unittest.py \
-	test/py/ganeti.bdev_unittest.py \
+	test/py/ganeti.block.bdev_unittest.py \
 	test/py/ganeti.cli_unittest.py \
 	test/py/ganeti.client.gnt_cluster_unittest.py \
 	test/py/ganeti.client.gnt_instance_unittest.py \
@@ -1232,6 +1237,7 @@ all_python_code = \
 	$(pkgpython_PYTHON) \
 	$(client_PYTHON) \
 	$(hypervisor_PYTHON) \
+	$(block_PYTHON) \
 	$(rapi_PYTHON) \
 	$(server_PYTHON) \
 	$(pytools_PYTHON) \
diff --git a/lib/backend.py b/lib/backend.py
index 7d8315d..c4f8d82 100644
--- a/lib/backend.py
+++ b/lib/backend.py
@@ -54,7 +54,7 @@ from ganeti import utils
 from ganeti import ssh
 from ganeti import hypervisor
 from ganeti import constants
-from ganeti import bdev
+from ganeti.block import bdev
 from ganeti import objects
 from ganeti import ssconf
 from ganeti import serializer
diff --git a/lib/bdev.py b/lib/bdev.py
deleted file mode 100644
index 649d92e..0000000
--- a/lib/bdev.py
+++ /dev/null
@@ -1,3442 +0,0 @@
-#
-#
-
-# Copyright (C) 2006, 2007, 2010, 2011, 2012, 2013 Google Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful, but
-# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-# 02110-1301, USA.
-
-
-"""Block device abstraction"""
-
-import re
-import time
-import errno
-import shlex
-import stat
-import pyparsing as pyp
-import os
-import logging
-import math
-
-from ganeti import utils
-from ganeti import errors
-from ganeti import constants
-from ganeti import objects
-from ganeti import compat
-from ganeti import netutils
-from ganeti import pathutils
-from ganeti import serializer
-
-
-# Size of reads in _CanReadDevice
-_DEVICE_READ_SIZE = 128 * 1024
-
-
-class RbdShowmappedJsonError(Exception):
-  """`rbd showmmapped' JSON formatting error Exception class.
-
-  """
-  pass
-
-
-def _IgnoreError(fn, *args, **kwargs):
-  """Executes the given function, ignoring BlockDeviceErrors.
-
-  This is used in order to simplify the execution of cleanup or
-  rollback functions.
-
-  @rtype: boolean
-  @return: True when fn didn't raise an exception, False otherwise
-
-  """
-  try:
-    fn(*args, **kwargs)
-    return True
-  except errors.BlockDeviceError, err:
-    logging.warning("Caught BlockDeviceError but ignoring: %s", str(err))
-    return False
-
-
-def _ThrowError(msg, *args):
-  """Log an error to the node daemon and the raise an exception.
-
-  @type msg: string
-  @param msg: the text of the exception
-  @raise errors.BlockDeviceError
-
-  """
-  if args:
-    msg = msg % args
-  logging.error(msg)
-  raise errors.BlockDeviceError(msg)
-
-
-def _CheckResult(result):
-  """Throws an error if the given result is a failed one.
-
-  @param result: result from RunCmd
-
-  """
-  if result.failed:
-    _ThrowError("Command: %s error: %s - %s", result.cmd, result.fail_reason,
-                result.output)
-
-
-def _CanReadDevice(path):
-  """Check if we can read from the given device.
-
-  This tries to read the first 128k of the device.
-
-  """
-  try:
-    utils.ReadFile(path, size=_DEVICE_READ_SIZE)
-    return True
-  except EnvironmentError:
-    logging.warning("Can't read from device %s", path, exc_info=True)
-    return False
-
-
-def _GetForbiddenFileStoragePaths():
-  """Builds a list of path prefixes which shouldn't be used for file storage.
-
-  @rtype: frozenset
-
-  """
-  paths = set([
-    "/boot",
-    "/dev",
-    "/etc",
-    "/home",
-    "/proc",
-    "/root",
-    "/sys",
-    ])
-
-  for prefix in ["", "/usr", "/usr/local"]:
-    paths.update(map(lambda s: "%s/%s" % (prefix, s),
-                     ["bin", "lib", "lib32", "lib64", "sbin"]))
-
-  return compat.UniqueFrozenset(map(os.path.normpath, paths))
-
-
-def _ComputeWrongFileStoragePaths(paths,
-                                  _forbidden=_GetForbiddenFileStoragePaths()):
-  """Cross-checks a list of paths for prefixes considered bad.
-
-  Some paths, e.g. "/bin", should not be used for file storage.
-
-  @type paths: list
-  @param paths: List of paths to be checked
-  @rtype: list
-  @return: Sorted list of paths for which the user should be warned
-
-  """
-  def _Check(path):
-    return (not os.path.isabs(path) or
-            path in _forbidden or
-            filter(lambda p: utils.IsBelowDir(p, path), _forbidden))
-
-  return utils.NiceSort(filter(_Check, map(os.path.normpath, paths)))
-
-
-def ComputeWrongFileStoragePaths(_filename=pathutils.FILE_STORAGE_PATHS_FILE):
-  """Returns a list of file storage paths whose prefix is considered bad.
-
-  See L{_ComputeWrongFileStoragePaths}.
-
-  """
-  return _ComputeWrongFileStoragePaths(_LoadAllowedFileStoragePaths(_filename))
-
-
-def _CheckFileStoragePath(path, allowed):
-  """Checks if a path is in a list of allowed paths for file storage.
-
-  @type path: string
-  @param path: Path to check
-  @type allowed: list
-  @param allowed: List of allowed paths
-  @raise errors.FileStoragePathError: If the path is not allowed
-
-  """
-  if not os.path.isabs(path):
-    raise errors.FileStoragePathError("File storage path must be absolute,"
-                                      " got '%s'" % path)
-
-  for i in allowed:
-    if not os.path.isabs(i):
-      logging.info("Ignoring relative path '%s' for file storage", i)
-      continue
-
-    if utils.IsBelowDir(i, path):
-      break
-  else:
-    raise errors.FileStoragePathError("Path '%s' is not acceptable for file"
-                                      " storage" % path)
-
-
-def _LoadAllowedFileStoragePaths(filename):
-  """Loads file containing allowed file storage paths.
-
-  @rtype: list
-  @return: List of allowed paths (can be an empty list)
-
-  """
-  try:
-    contents = utils.ReadFile(filename)
-  except EnvironmentError:
-    return []
-  else:
-    return utils.FilterEmptyLinesAndComments(contents)
-
-
-def CheckFileStoragePath(path, _filename=pathutils.FILE_STORAGE_PATHS_FILE):
-  """Checks if a path is allowed for file storage.
-
-  @type path: string
-  @param path: Path to check
-  @raise errors.FileStoragePathError: If the path is not allowed
-
-  """
-  allowed = _LoadAllowedFileStoragePaths(_filename)
-
-  if _ComputeWrongFileStoragePaths([path]):
-    raise errors.FileStoragePathError("Path '%s' uses a forbidden prefix" %
-                                      path)
-
-  _CheckFileStoragePath(path, allowed)
-
-
-class BlockDev(object):
-  """Block device abstract class.
-
-  A block device can be in the following states:
-    - not existing on the system, and by `Create()` it goes into:
-    - existing but not setup/not active, and by `Assemble()` goes into:
-    - active read-write and by `Open()` it goes into
-    - online (=used, or ready for use)
-
-  A device can also be online but read-only, however we are not using
-  the readonly state (LV has it, if needed in the future) and we are
-  usually looking at this like at a stack, so it's easier to
-  conceptualise the transition from not-existing to online and back
-  like a linear one.
-
-  The many different states of the device are due to the fact that we
-  need to cover many device types:
-    - logical volumes are created, lvchange -a y $lv, and used
-    - drbd devices are attached to a local disk/remote peer and made primary
-
-  A block device is identified by three items:
-    - the /dev path of the device (dynamic)
-    - a unique ID of the device (static)
-    - it's major/minor pair (dynamic)
-
-  Not all devices implement both the first two as distinct items. LVM
-  logical volumes have their unique ID (the pair volume group, logical
-  volume name) in a 1-to-1 relation to the dev path. For DRBD devices,
-  the /dev path is again dynamic and the unique id is the pair (host1,
-  dev1), (host2, dev2).
-
-  You can get to a device in two ways:
-    - creating the (real) device, which returns you
-      an attached instance (lvcreate)
-    - attaching of a python instance to an existing (real) device
-
-  The second point, the attachment to a device, is different
-  depending on whether the device is assembled or not. At init() time,
-  we search for a device with the same unique_id as us. If found,
-  good. It also means that the device is already assembled. If not,
-  after assembly we'll have our correct major/minor.
-
-  """
-  def __init__(self, unique_id, children, size, params):
-    self._children = children
-    self.dev_path = None
-    self.unique_id = unique_id
-    self.major = None
-    self.minor = None
-    self.attached = False
-    self.size = size
-    self.params = params
-
-  def Assemble(self):
-    """Assemble the device from its components.
-
-    Implementations of this method by child classes must ensure that:
-      - after the device has been assembled, it knows its major/minor
-        numbers; this allows other devices (usually parents) to probe
-        correctly for their children
-      - calling this method on an existing, in-use device is safe
-      - if the device is already configured (and in an OK state),
-        this method is idempotent
-
-    """
-    pass
-
-  def Attach(self):
-    """Find a device which matches our config and attach to it.
-
-    """
-    raise NotImplementedError
-
-  def Close(self):
-    """Notifies that the device will no longer be used for I/O.
-
-    """
-    raise NotImplementedError
-
-  @classmethod
-  def Create(cls, unique_id, children, size, params, excl_stor):
-    """Create the device.
-
-    If the device cannot be created, it will return None
-    instead. Error messages go to the logging system.
-
-    Note that for some devices, the unique_id is used, and for other,
-    the children. The idea is that these two, taken together, are
-    enough for both creation and assembly (later).
-
-    """
-    raise NotImplementedError
-
-  def Remove(self):
-    """Remove this device.
-
-    This makes sense only for some of the device types: LV and file
-    storage. Also note that if the device can't attach, the removal
-    can't be completed.
-
-    """
-    raise NotImplementedError
-
-  def Rename(self, new_id):
-    """Rename this device.
-
-    This may or may not make sense for a given device type.
-
-    """
-    raise NotImplementedError
-
-  def Open(self, force=False):
-    """Make the device ready for use.
-
-    This makes the device ready for I/O. For now, just the DRBD
-    devices need this.
-
-    The force parameter signifies that if the device has any kind of
-    --force thing, it should be used, we know what we are doing.
-
-    """
-    raise NotImplementedError
-
-  def Shutdown(self):
-    """Shut down the device, freeing its children.
-
-    This undoes the `Assemble()` work, except for the child
-    assembling; as such, the children on the device are still
-    assembled after this call.
-
-    """
-    raise NotImplementedError
-
-  def SetSyncParams(self, params):
-    """Adjust the synchronization parameters of the mirror.
-
-    In case this is not a mirroring device, this is no-op.
-
-    @param params: dictionary of LD level disk parameters related to the
-    synchronization.
-    @rtype: list
-    @return: a list of error messages, emitted both by the current node and by
-    children. An empty list means no errors.
-
-    """
-    result = []
-    if self._children:
-      for child in self._children:
-        result.extend(child.SetSyncParams(params))
-    return result
-
-  def PauseResumeSync(self, pause):
-    """Pause/Resume the sync of the mirror.
-
-    In case this is not a mirroring device, this is no-op.
-
-    @param pause: Whether to pause or resume
-
-    """
-    result = True
-    if self._children:
-      for child in self._children:
-        result = result and child.PauseResumeSync(pause)
-    return result
-
-  def GetSyncStatus(self):
-    """Returns the sync status of the device.
-
-    If this device is a mirroring device, this function returns the
-    status of the mirror.
-
-    If sync_percent is None, it means the device is not syncing.
-
-    If estimated_time is None, it means we can't estimate
-    the time needed, otherwise it's the time left in seconds.
-
-    If is_degraded is True, it means the device is missing
-    redundancy. This is usually a sign that something went wrong in
-    the device setup, if sync_percent is None.
-
-    The ldisk parameter represents the degradation of the local
-    data. This is only valid for some devices, the rest will always
-    return False (not degraded).
-
-    @rtype: objects.BlockDevStatus
-
-    """
-    return objects.BlockDevStatus(dev_path=self.dev_path,
-                                  major=self.major,
-                                  minor=self.minor,
-                                  sync_percent=None,
-                                  estimated_time=None,
-                                  is_degraded=False,
-                                  ldisk_status=constants.LDS_OKAY)
-
-  def CombinedSyncStatus(self):
-    """Calculate the mirror status recursively for our children.
-
-    The return value is the same as for `GetSyncStatus()` except the
-    minimum percent and maximum time are calculated across our
-    children.
-
-    @rtype: objects.BlockDevStatus
-
-    """
-    status = self.GetSyncStatus()
-
-    min_percent = status.sync_percent
-    max_time = status.estimated_time
-    is_degraded = status.is_degraded
-    ldisk_status = status.ldisk_status
-
-    if self._children:
-      for child in self._children:
-        child_status = child.GetSyncStatus()
-
-        if min_percent is None:
-          min_percent = child_status.sync_percent
-        elif child_status.sync_percent is not None:
-          min_percent = min(min_percent, child_status.sync_percent)
-
-        if max_time is None:
-          max_time = child_status.estimated_time
-        elif child_status.estimated_time is not None:
-          max_time = max(max_time, child_status.estimated_time)
-
-        is_degraded = is_degraded or child_status.is_degraded
-
-        if ldisk_status is None:
-          ldisk_status = child_status.ldisk_status
-        elif child_status.ldisk_status is not None:
-          ldisk_status = max(ldisk_status, child_status.ldisk_status)
-
-    return objects.BlockDevStatus(dev_path=self.dev_path,
-                                  major=self.major,
-                                  minor=self.minor,
-                                  sync_percent=min_percent,
-                                  estimated_time=max_time,
-                                  is_degraded=is_degraded,
-                                  ldisk_status=ldisk_status)
-
-  def SetInfo(self, text):
-    """Update metadata with info text.
-
-    Only supported for some device types.
-
-    """
-    for child in self._children:
-      child.SetInfo(text)
-
-  def Grow(self, amount, dryrun, backingstore):
-    """Grow the block device.
-
-    @type amount: integer
-    @param amount: the amount (in mebibytes) to grow with
-    @type dryrun: boolean
-    @param dryrun: whether to execute the operation in simulation mode
-        only, without actually increasing the size
-    @param backingstore: whether to execute the operation on backing storage
-        only, or on "logical" storage only; e.g. DRBD is logical storage,
-        whereas LVM, file, RBD are backing storage
-
-    """
-    raise NotImplementedError
-
-  def GetActualSize(self):
-    """Return the actual disk size.
-
-    @note: the device needs to be active when this is called
-
-    """
-    assert self.attached, "BlockDevice not attached in GetActualSize()"
-    result = utils.RunCmd(["blockdev", "--getsize64", self.dev_path])
-    if result.failed:
-      _ThrowError("blockdev failed (%s): %s",
-                  result.fail_reason, result.output)
-    try:
-      sz = int(result.output.strip())
-    except (ValueError, TypeError), err:
-      _ThrowError("Failed to parse blockdev output: %s", str(err))
-    return sz
-
-  def __repr__(self):
-    return ("<%s: unique_id: %s, children: %s, %s:%s, %s>" %
-            (self.__class__, self.unique_id, self._children,
-             self.major, self.minor, self.dev_path))
-
-
-class LogicalVolume(BlockDev):
-  """Logical Volume block device.
-
-  """
-  _VALID_NAME_RE = re.compile("^[a-zA-Z0-9+_.-]*$")
-  _INVALID_NAMES = compat.UniqueFrozenset([".", "..", "snapshot", "pvmove"])
-  _INVALID_SUBSTRINGS = compat.UniqueFrozenset(["_mlog", "_mimage"])
-
-  def __init__(self, unique_id, children, size, params):
-    """Attaches to a LV device.
-
-    The unique_id is a tuple (vg_name, lv_name)
-
-    """
-    super(LogicalVolume, self).__init__(unique_id, children, size, params)
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise ValueError("Invalid configuration data %s" % str(unique_id))
-    self._vg_name, self._lv_name = unique_id
-    self._ValidateName(self._vg_name)
-    self._ValidateName(self._lv_name)
-    self.dev_path = utils.PathJoin("/dev", self._vg_name, self._lv_name)
-    self._degraded = True
-    self.major = self.minor = self.pe_size = self.stripe_count = None
-    self.Attach()
-
-  @staticmethod
-  def _GetStdPvSize(pvs_info):
-    """Return the the standard PV size (used with exclusive storage).
-
-    @param pvs_info: list of objects.LvmPvInfo, cannot be empty
-    @rtype: float
-    @return: size in MiB
-
-    """
-    assert len(pvs_info) > 0
-    smallest = min([pv.size for pv in pvs_info])
-    return smallest / (1 + constants.PART_MARGIN + constants.PART_RESERVED)
-
-  @staticmethod
-  def _ComputeNumPvs(size, pvs_info):
-    """Compute the number of PVs needed for an LV (with exclusive storage).
-
-    @type size: float
-    @param size: LV size in MiB
-    @param pvs_info: list of objects.LvmPvInfo, cannot be empty
-    @rtype: integer
-    @return: number of PVs needed
-    """
-    assert len(pvs_info) > 0
-    pv_size = float(LogicalVolume._GetStdPvSize(pvs_info))
-    return int(math.ceil(float(size) / pv_size))
-
-  @staticmethod
-  def _GetEmptyPvNames(pvs_info, max_pvs=None):
-    """Return a list of empty PVs, by name.
-
-    """
-    empty_pvs = filter(objects.LvmPvInfo.IsEmpty, pvs_info)
-    if max_pvs is not None:
-      empty_pvs = empty_pvs[:max_pvs]
-    return map((lambda pv: pv.name), empty_pvs)
-
-  @classmethod
-  def Create(cls, unique_id, children, size, params, excl_stor):
-    """Create a new logical volume.
-
-    """
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise errors.ProgrammerError("Invalid configuration data %s" %
-                                   str(unique_id))
-    vg_name, lv_name = unique_id
-    cls._ValidateName(vg_name)
-    cls._ValidateName(lv_name)
-    pvs_info = cls.GetPVInfo([vg_name])
-    if not pvs_info:
-      if excl_stor:
-        msg = "No (empty) PVs found"
-      else:
-        msg = "Can't compute PV info for vg %s" % vg_name
-      _ThrowError(msg)
-    pvs_info.sort(key=(lambda pv: pv.free), reverse=True)
-
-    pvlist = [pv.name for pv in pvs_info]
-    if compat.any(":" in v for v in pvlist):
-      _ThrowError("Some of your PVs have the invalid character ':' in their"
-                  " name, this is not supported - please filter them out"
-                  " in lvm.conf using either 'filter' or 'preferred_names'")
-
-    current_pvs = len(pvlist)
-    desired_stripes = params[constants.LDP_STRIPES]
-    stripes = min(current_pvs, desired_stripes)
-
-    if excl_stor:
-      (err_msgs, _) = utils.LvmExclusiveCheckNodePvs(pvs_info)
-      if err_msgs:
-        for m in err_msgs:
-          logging.warning(m)
-      req_pvs = cls._ComputeNumPvs(size, pvs_info)
-      pvlist = cls._GetEmptyPvNames(pvs_info, req_pvs)
-      current_pvs = len(pvlist)
-      if current_pvs < req_pvs:
-        _ThrowError("Not enough empty PVs to create a disk of %d MB:"
-                    " %d available, %d needed", size, current_pvs, req_pvs)
-      assert current_pvs == len(pvlist)
-      if stripes > current_pvs:
-        # No warning issued for this, as it's no surprise
-        stripes = current_pvs
-
-    else:
-      if stripes < desired_stripes:
-        logging.warning("Could not use %d stripes for VG %s, as only %d PVs are"
-                        " available.", desired_stripes, vg_name, current_pvs)
-      free_size = sum([pv.free for pv in pvs_info])
-      # The size constraint should have been checked from the master before
-      # calling the create function.
-      if free_size < size:
-        _ThrowError("Not enough free space: required %s,"
-                    " available %s", size, free_size)
-
-    # If the free space is not well distributed, we won't be able to
-    # create an optimally-striped volume; in that case, we want to try
-    # with N, N-1, ..., 2, and finally 1 (non-stripped) number of
-    # stripes
-    cmd = ["lvcreate", "-L%dm" % size, "-n%s" % lv_name]
-    for stripes_arg in range(stripes, 0, -1):
-      result = utils.RunCmd(cmd + ["-i%d" % stripes_arg] + [vg_name] + pvlist)
-      if not result.failed:
-        break
-    if result.failed:
-      _ThrowError("LV create failed (%s): %s",
-                  result.fail_reason, result.output)
-    return LogicalVolume(unique_id, children, size, params)
-
-  @staticmethod
-  def _GetVolumeInfo(lvm_cmd, fields):
-    """Returns LVM Volume infos using lvm_cmd
-
-    @param lvm_cmd: Should be one of "pvs", "vgs" or "lvs"
-    @param fields: Fields to return
-    @return: A list of dicts each with the parsed fields
-
-    """
-    if not fields:
-      raise errors.ProgrammerError("No fields specified")
-
-    sep = "|"
-    cmd = [lvm_cmd, "--noheadings", "--nosuffix", "--units=m", "--unbuffered",
-           "--separator=%s" % sep, "-o%s" % ",".join(fields)]
-
-    result = utils.RunCmd(cmd)
-    if result.failed:
-      raise errors.CommandError("Can't get the volume information: %s - %s" %
-                                (result.fail_reason, result.output))
-
-    data = []
-    for line in result.stdout.splitlines():
-      splitted_fields = line.strip().split(sep)
-
-      if len(fields) != len(splitted_fields):
-        raise errors.CommandError("Can't parse %s output: line '%s'" %
-                                  (lvm_cmd, line))
-
-      data.append(splitted_fields)
-
-    return data
-
-  @classmethod
-  def GetPVInfo(cls, vg_names, filter_allocatable=True, include_lvs=False):
-    """Get the free space info for PVs in a volume group.
-
-    @param vg_names: list of volume group names, if empty all will be returned
-    @param filter_allocatable: whether to skip over unallocatable PVs
-    @param include_lvs: whether to include a list of LVs hosted on each PV
-
-    @rtype: list
-    @return: list of objects.LvmPvInfo objects
-
-    """
-    # We request "lv_name" field only if we care about LVs, so we don't get
-    # a long list of entries with many duplicates unless we really have to.
-    # The duplicate "pv_name" field will be ignored.
-    if include_lvs:
-      lvfield = "lv_name"
-    else:
-      lvfield = "pv_name"
-    try:
-      info = cls._GetVolumeInfo("pvs", ["pv_name", "vg_name", "pv_free",
-                                        "pv_attr", "pv_size", lvfield])
-    except errors.GenericError, err:
-      logging.error("Can't get PV information: %s", err)
-      return None
-
-    # When asked for LVs, "pvs" may return multiple entries for the same PV-LV
-    # pair. We sort entries by PV name and then LV name, so it's easy to weed
-    # out duplicates.
-    if include_lvs:
-      info.sort(key=(lambda i: (i[0], i[5])))
-    data = []
-    lastpvi = None
-    for (pv_name, vg_name, pv_free, pv_attr, pv_size, lv_name) in info:
-      # (possibly) skip over pvs which are not allocatable
-      if filter_allocatable and pv_attr[0] != "a":
-        continue
-      # (possibly) skip over pvs which are not in the right volume group(s)
-      if vg_names and vg_name not in vg_names:
-        continue
-      # Beware of duplicates (check before inserting)
-      if lastpvi and lastpvi.name == pv_name:
-        if include_lvs and lv_name:
-          if not lastpvi.lv_list or lastpvi.lv_list[-1] != lv_name:
-            lastpvi.lv_list.append(lv_name)
-      else:
-        if include_lvs and lv_name:
-          lvl = [lv_name]
-        else:
-          lvl = []
-        lastpvi = objects.LvmPvInfo(name=pv_name, vg_name=vg_name,
-                                    size=float(pv_size), free=float(pv_free),
-                                    attributes=pv_attr, lv_list=lvl)
-        data.append(lastpvi)
-
-    return data
-
-  @classmethod
-  def _GetExclusiveStorageVgFree(cls, vg_name):
-    """Return the free disk space in the given VG, in exclusive storage mode.
-
-    @type vg_name: string
-    @param vg_name: VG name
-    @rtype: float
-    @return: free space in MiB
-    """
-    pvs_info = cls.GetPVInfo([vg_name])
-    if not pvs_info:
-      return 0.0
-    pv_size = cls._GetStdPvSize(pvs_info)
-    num_pvs = len(cls._GetEmptyPvNames(pvs_info))
-    return pv_size * num_pvs
-
-  @classmethod
-  def GetVGInfo(cls, vg_names, excl_stor, filter_readonly=True):
-    """Get the free space info for specific VGs.
-
-    @param vg_names: list of volume group names, if empty all will be returned
-    @param excl_stor: whether exclusive_storage is enabled
-    @param filter_readonly: whether to skip over readonly VGs
-
-    @rtype: list
-    @return: list of tuples (free_space, total_size, name) with free_space in
-             MiB
-
-    """
-    try:
-      info = cls._GetVolumeInfo("vgs", ["vg_name", "vg_free", "vg_attr",
-                                        "vg_size"])
-    except errors.GenericError, err:
-      logging.error("Can't get VG information: %s", err)
-      return None
-
-    data = []
-    for vg_name, vg_free, vg_attr, vg_size in info:
-      # (possibly) skip over vgs which are not writable
-      if filter_readonly and vg_attr[0] == "r":
-        continue
-      # (possibly) skip over vgs which are not in the right volume group(s)
-      if vg_names and vg_name not in vg_names:
-        continue
-      # Exclusive storage needs a different concept of free space
-      if excl_stor:
-        es_free = cls._GetExclusiveStorageVgFree(vg_name)
-        assert es_free <= vg_free
-        vg_free = es_free
-      data.append((float(vg_free), float(vg_size), vg_name))
-
-    return data
-
-  @classmethod
-  def _ValidateName(cls, name):
-    """Validates that a given name is valid as VG or LV name.
-
-    The list of valid characters and restricted names is taken out of
-    the lvm(8) manpage, with the simplification that we enforce both
-    VG and LV restrictions on the names.
-
-    """
-    if (not cls._VALID_NAME_RE.match(name) or
-        name in cls._INVALID_NAMES or
-        compat.any(substring in name for substring in cls._INVALID_SUBSTRINGS)):
-      _ThrowError("Invalid LVM name '%s'", name)
-
-  def Remove(self):
-    """Remove this logical volume.
-
-    """
-    if not self.minor and not self.Attach():
-      # the LV does not exist
-      return
-    result = utils.RunCmd(["lvremove", "-f", "%s/%s" %
-                           (self._vg_name, self._lv_name)])
-    if result.failed:
-      _ThrowError("Can't lvremove: %s - %s", result.fail_reason, result.output)
-
-  def Rename(self, new_id):
-    """Rename this logical volume.
-
-    """
-    if not isinstance(new_id, (tuple, list)) or len(new_id) != 2:
-      raise errors.ProgrammerError("Invalid new logical id '%s'" % new_id)
-    new_vg, new_name = new_id
-    if new_vg != self._vg_name:
-      raise errors.ProgrammerError("Can't move a logical volume across"
-                                   " volume groups (from %s to to %s)" %
-                                   (self._vg_name, new_vg))
-    result = utils.RunCmd(["lvrename", new_vg, self._lv_name, new_name])
-    if result.failed:
-      _ThrowError("Failed to rename the logical volume: %s", result.output)
-    self._lv_name = new_name
-    self.dev_path = utils.PathJoin("/dev", self._vg_name, self._lv_name)
-
-  def Attach(self):
-    """Attach to an existing LV.
-
-    This method will try to see if an existing and active LV exists
-    which matches our name. If so, its major/minor will be
-    recorded.
-
-    """
-    self.attached = False
-    result = utils.RunCmd(["lvs", "--noheadings", "--separator=,",
-                           "--units=m", "--nosuffix",
-                           "-olv_attr,lv_kernel_major,lv_kernel_minor,"
-                           "vg_extent_size,stripes", self.dev_path])
-    if result.failed:
-      logging.error("Can't find LV %s: %s, %s",
-                    self.dev_path, result.fail_reason, result.output)
-      return False
-    # the output can (and will) have multiple lines for multi-segment
-    # LVs, as the 'stripes' parameter is a segment one, so we take
-    # only the last entry, which is the one we're interested in; note
-    # that with LVM2 anyway the 'stripes' value must be constant
-    # across segments, so this is a no-op actually
-    out = result.stdout.splitlines()
-    if not out: # totally empty result? splitlines() returns at least
-                # one line for any non-empty string
-      logging.error("Can't parse LVS output, no lines? Got '%s'", str(out))
-      return False
-    out = out[-1].strip().rstrip(",")
-    out = out.split(",")
-    if len(out) != 5:
-      logging.error("Can't parse LVS output, len(%s) != 5", str(out))
-      return False
-
-    status, major, minor, pe_size, stripes = out
-    if len(status) < 6:
-      logging.error("lvs lv_attr is not at least 6 characters (%s)", status)
-      return False
-
-    try:
-      major = int(major)
-      minor = int(minor)
-    except (TypeError, ValueError), err:
-      logging.error("lvs major/minor cannot be parsed: %s", str(err))
-
-    try:
-      pe_size = int(float(pe_size))
-    except (TypeError, ValueError), err:
-      logging.error("Can't parse vg extent size: %s", err)
-      return False
-
-    try:
-      stripes = int(stripes)
-    except (TypeError, ValueError), err:
-      logging.error("Can't parse the number of stripes: %s", err)
-      return False
-
-    self.major = major
-    self.minor = minor
-    self.pe_size = pe_size
-    self.stripe_count = stripes
-    self._degraded = status[0] == "v" # virtual volume, i.e. doesn't backing
-                                      # storage
-    self.attached = True
-    return True
-
-  def Assemble(self):
-    """Assemble the device.
-
-    We always run `lvchange -ay` on the LV to ensure it's active before
-    use, as there were cases when xenvg was not active after boot
-    (also possibly after disk issues).
-
-    """
-    result = utils.RunCmd(["lvchange", "-ay", self.dev_path])
-    if result.failed:
-      _ThrowError("Can't activate lv %s: %s", self.dev_path, result.output)
-
-  def Shutdown(self):
-    """Shutdown the device.
-
-    This is a no-op for the LV device type, as we don't deactivate the
-    volumes on shutdown.
-
-    """
-    pass
-
-  def GetSyncStatus(self):
-    """Returns the sync status of the device.
-
-    If this device is a mirroring device, this function returns the
-    status of the mirror.
-
-    For logical volumes, sync_percent and estimated_time are always
-    None (no recovery in progress, as we don't handle the mirrored LV
-    case). The is_degraded parameter is the inverse of the ldisk
-    parameter.
-
-    For the ldisk parameter, we check if the logical volume has the
-    'virtual' type, which means it's not backed by existing storage
-    anymore (read from it return I/O error). This happens after a
-    physical disk failure and subsequent 'vgreduce --removemissing' on
-    the volume group.
-
-    The status was already read in Attach, so we just return it.
-
-    @rtype: objects.BlockDevStatus
-
-    """
-    if self._degraded:
-      ldisk_status = constants.LDS_FAULTY
-    else:
-      ldisk_status = constants.LDS_OKAY
-
-    return objects.BlockDevStatus(dev_path=self.dev_path,
-                                  major=self.major,
-                                  minor=self.minor,
-                                  sync_percent=None,
-                                  estimated_time=None,
-                                  is_degraded=self._degraded,
-                                  ldisk_status=ldisk_status)
-
-  def Open(self, force=False):
-    """Make the device ready for I/O.
-
-    This is a no-op for the LV device type.
-
-    """
-    pass
-
-  def Close(self):
-    """Notifies that the device will no longer be used for I/O.
-
-    This is a no-op for the LV device type.
-
-    """
-    pass
-
-  def Snapshot(self, size):
-    """Create a snapshot copy of an lvm block device.
-
-    @returns: tuple (vg, lv)
-
-    """
-    snap_name = self._lv_name + ".snap"
-
-    # remove existing snapshot if found
-    snap = LogicalVolume((self._vg_name, snap_name), None, size, self.params)
-    _IgnoreError(snap.Remove)
-
-    vg_info = self.GetVGInfo([self._vg_name], False)
-    if not vg_info:
-      _ThrowError("Can't compute VG info for vg %s", self._vg_name)
-    free_size, _, _ = vg_info[0]
-    if free_size < size:
-      _ThrowError("Not enough free space: required %s,"
-                  " available %s", size, free_size)
-
-    _CheckResult(utils.RunCmd(["lvcreate", "-L%dm" % size, "-s",
-                               "-n%s" % snap_name, self.dev_path]))
-
-    return (self._vg_name, snap_name)
-
-  def _RemoveOldInfo(self):
-    """Try to remove old tags from the lv.
-
-    """
-    result = utils.RunCmd(["lvs", "-o", "tags", "--noheadings", "--nosuffix",
-                           self.dev_path])
-    _CheckResult(result)
-
-    raw_tags = result.stdout.strip()
-    if raw_tags:
-      for tag in raw_tags.split(","):
-        _CheckResult(utils.RunCmd(["lvchange", "--deltag",
-                                   tag.strip(), self.dev_path]))
-
-  def SetInfo(self, text):
-    """Update metadata with info text.
-
-    """
-    BlockDev.SetInfo(self, text)
-
-    self._RemoveOldInfo()
-
-    # Replace invalid characters
-    text = re.sub("^[^A-Za-z0-9_+.]", "_", text)
-    text = re.sub("[^-A-Za-z0-9_+.]", "_", text)
-
-    # Only up to 128 characters are allowed
-    text = text[:128]
-
-    _CheckResult(utils.RunCmd(["lvchange", "--addtag", text, self.dev_path]))
-
-  def Grow(self, amount, dryrun, backingstore):
-    """Grow the logical volume.
-
-    """
-    if not backingstore:
-      return
-    if self.pe_size is None or self.stripe_count is None:
-      if not self.Attach():
-        _ThrowError("Can't attach to LV during Grow()")
-    full_stripe_size = self.pe_size * self.stripe_count
-    rest = amount % full_stripe_size
-    if rest != 0:
-      amount += full_stripe_size - rest
-    cmd = ["lvextend", "-L", "+%dm" % amount]
-    if dryrun:
-      cmd.append("--test")
-    # we try multiple algorithms since the 'best' ones might not have
-    # space available in the right place, but later ones might (since
-    # they have less constraints); also note that only recent LVM
-    # supports 'cling'
-    for alloc_policy in "contiguous", "cling", "normal":
-      result = utils.RunCmd(cmd + ["--alloc", alloc_policy, self.dev_path])
-      if not result.failed:
-        return
-    _ThrowError("Can't grow LV %s: %s", self.dev_path, result.output)
-
-
-class DRBD8Status(object):
-  """A DRBD status representation class.
-
-  Note that this doesn't support unconfigured devices (cs:Unconfigured).
-
-  """
-  UNCONF_RE = re.compile(r"\s*[0-9]+:\s*cs:Unconfigured$")
-  LINE_RE = re.compile(r"\s*[0-9]+:\s*cs:(\S+)\s+(?:st|ro):([^/]+)/(\S+)"
-                       "\s+ds:([^/]+)/(\S+)\s+.*$")
-  SYNC_RE = re.compile(r"^.*\ssync'ed:\s*([0-9.]+)%.*"
-                       # Due to a bug in drbd in the kernel, introduced in
-                       # commit 4b0715f096 (still unfixed as of 2011-08-22)
-                       "(?:\s|M)"
-                       "finish: ([0-9]+):([0-9]+):([0-9]+)\s.*$")
-
-  CS_UNCONFIGURED = "Unconfigured"
-  CS_STANDALONE = "StandAlone"
-  CS_WFCONNECTION = "WFConnection"
-  CS_WFREPORTPARAMS = "WFReportParams"
-  CS_CONNECTED = "Connected"
-  CS_STARTINGSYNCS = "StartingSyncS"
-  CS_STARTINGSYNCT = "StartingSyncT"
-  CS_WFBITMAPS = "WFBitMapS"
-  CS_WFBITMAPT = "WFBitMapT"
-  CS_WFSYNCUUID = "WFSyncUUID"
-  CS_SYNCSOURCE = "SyncSource"
-  CS_SYNCTARGET = "SyncTarget"
-  CS_PAUSEDSYNCS = "PausedSyncS"
-  CS_PAUSEDSYNCT = "PausedSyncT"
-  CSET_SYNC = compat.UniqueFrozenset([
-    CS_WFREPORTPARAMS,
-    CS_STARTINGSYNCS,
-    CS_STARTINGSYNCT,
-    CS_WFBITMAPS,
-    CS_WFBITMAPT,
-    CS_WFSYNCUUID,
-    CS_SYNCSOURCE,
-    CS_SYNCTARGET,
-    CS_PAUSEDSYNCS,
-    CS_PAUSEDSYNCT,
-    ])
-
-  DS_DISKLESS = "Diskless"
-  DS_ATTACHING = "Attaching" # transient state
-  DS_FAILED = "Failed" # transient state, next: diskless
-  DS_NEGOTIATING = "Negotiating" # transient state
-  DS_INCONSISTENT = "Inconsistent" # while syncing or after creation
-  DS_OUTDATED = "Outdated"
-  DS_DUNKNOWN = "DUnknown" # shown for peer disk when not connected
-  DS_CONSISTENT = "Consistent"
-  DS_UPTODATE = "UpToDate" # normal state
-
-  RO_PRIMARY = "Primary"
-  RO_SECONDARY = "Secondary"
-  RO_UNKNOWN = "Unknown"
-
-  def __init__(self, procline):
-    u = self.UNCONF_RE.match(procline)
-    if u:
-      self.cstatus = self.CS_UNCONFIGURED
-      self.lrole = self.rrole = self.ldisk = self.rdisk = None
-    else:
-      m = self.LINE_RE.match(procline)
-      if not m:
-        raise errors.BlockDeviceError("Can't parse input data '%s'" % procline)
-      self.cstatus = m.group(1)
-      self.lrole = m.group(2)
-      self.rrole = m.group(3)
-      self.ldisk = m.group(4)
-      self.rdisk = m.group(5)
-
-    # end reading of data from the LINE_RE or UNCONF_RE
-
-    self.is_standalone = self.cstatus == self.CS_STANDALONE
-    self.is_wfconn = self.cstatus == self.CS_WFCONNECTION
-    self.is_connected = self.cstatus == self.CS_CONNECTED
-    self.is_primary = self.lrole == self.RO_PRIMARY
-    self.is_secondary = self.lrole == self.RO_SECONDARY
-    self.peer_primary = self.rrole == self.RO_PRIMARY
-    self.peer_secondary = self.rrole == self.RO_SECONDARY
-    self.both_primary = self.is_primary and self.peer_primary
-    self.both_secondary = self.is_secondary and self.peer_secondary
-
-    self.is_diskless = self.ldisk == self.DS_DISKLESS
-    self.is_disk_uptodate = self.ldisk == self.DS_UPTODATE
-
-    self.is_in_resync = self.cstatus in self.CSET_SYNC
-    self.is_in_use = self.cstatus != self.CS_UNCONFIGURED
-
-    m = self.SYNC_RE.match(procline)
-    if m:
-      self.sync_percent = float(m.group(1))
-      hours = int(m.group(2))
-      minutes = int(m.group(3))
-      seconds = int(m.group(4))
-      self.est_time = hours * 3600 + minutes * 60 + seconds
-    else:
-      # we have (in this if branch) no percent information, but if
-      # we're resyncing we need to 'fake' a sync percent information,
-      # as this is how cmdlib determines if it makes sense to wait for
-      # resyncing or not
-      if self.is_in_resync:
-        self.sync_percent = 0
-      else:
-        self.sync_percent = None
-      self.est_time = None
-
-
-class BaseDRBD(BlockDev): # pylint: disable=W0223
-  """Base DRBD class.
-
-  This class contains a few bits of common functionality between the
-  0.7 and 8.x versions of DRBD.
-
-  """
-  _VERSION_RE = re.compile(r"^version: (\d+)\.(\d+)\.(\d+)(?:\.\d+)?"
-                           r" \(api:(\d+)/proto:(\d+)(?:-(\d+))?\)")
-  _VALID_LINE_RE = re.compile("^ *([0-9]+): cs:([^ ]+).*$")
-  _UNUSED_LINE_RE = re.compile("^ *([0-9]+): cs:Unconfigured$")
-
-  _DRBD_MAJOR = 147
-  _ST_UNCONFIGURED = "Unconfigured"
-  _ST_WFCONNECTION = "WFConnection"
-  _ST_CONNECTED = "Connected"
-
-  _STATUS_FILE = constants.DRBD_STATUS_FILE
-  _USERMODE_HELPER_FILE = "/sys/module/drbd/parameters/usermode_helper"
-
-  @staticmethod
-  def _GetProcData(filename=_STATUS_FILE):
-    """Return data from /proc/drbd.
-
-    """
-    try:
-      data = utils.ReadFile(filename).splitlines()
-    except EnvironmentError, err:
-      if err.errno == errno.ENOENT:
-        _ThrowError("The file %s cannot be opened, check if the module"
-                    " is loaded (%s)", filename, str(err))
-      else:
-        _ThrowError("Can't read the DRBD proc file %s: %s", filename, str(err))
-    if not data:
-      _ThrowError("Can't read any data from %s", filename)
-    return data
-
-  @classmethod
-  def _MassageProcData(cls, data):
-    """Transform the output of _GetProdData into a nicer form.
-
-    @return: a dictionary of minor: joined lines from /proc/drbd
-        for that minor
-
-    """
-    results = {}
-    old_minor = old_line = None
-    for line in data:
-      if not line: # completely empty lines, as can be returned by drbd8.0+
-        continue
-      lresult = cls._VALID_LINE_RE.match(line)
-      if lresult is not None:
-        if old_minor is not None:
-          results[old_minor] = old_line
-        old_minor = int(lresult.group(1))
-        old_line = line
-      else:
-        if old_minor is not None:
-          old_line += " " + line.strip()
-    # add last line
-    if old_minor is not None:
-      results[old_minor] = old_line
-    return results
-
-  @classmethod
-  def _GetVersion(cls, proc_data):
-    """Return the DRBD version.
-
-    This will return a dict with keys:
-      - k_major
-      - k_minor
-      - k_point
-      - api
-      - proto
-      - proto2 (only on drbd > 8.2.X)
-
-    """
-    first_line = proc_data[0].strip()
-    version = cls._VERSION_RE.match(first_line)
-    if not version:
-      raise errors.BlockDeviceError("Can't parse DRBD version from '%s'" %
-                                    first_line)
-
-    values = version.groups()
-    retval = {
-      "k_major": int(values[0]),
-      "k_minor": int(values[1]),
-      "k_point": int(values[2]),
-      "api": int(values[3]),
-      "proto": int(values[4]),
-      }
-    if values[5] is not None:
-      retval["proto2"] = values[5]
-
-    return retval
-
-  @staticmethod
-  def GetUsermodeHelper(filename=_USERMODE_HELPER_FILE):
-    """Returns DRBD usermode_helper currently set.
-
-    """
-    try:
-      helper = utils.ReadFile(filename).splitlines()[0]
-    except EnvironmentError, err:
-      if err.errno == errno.ENOENT:
-        _ThrowError("The file %s cannot be opened, check if the module"
-                    " is loaded (%s)", filename, str(err))
-      else:
-        _ThrowError("Can't read DRBD helper file %s: %s", filename, str(err))
-    if not helper:
-      _ThrowError("Can't read any data from %s", filename)
-    return helper
-
-  @staticmethod
-  def _DevPath(minor):
-    """Return the path to a drbd device for a given minor.
-
-    """
-    return "/dev/drbd%d" % minor
-
-  @classmethod
-  def GetUsedDevs(cls):
-    """Compute the list of used DRBD devices.
-
-    """
-    data = cls._GetProcData()
-
-    used_devs = {}
-    for line in data:
-      match = cls._VALID_LINE_RE.match(line)
-      if not match:
-        continue
-      minor = int(match.group(1))
-      state = match.group(2)
-      if state == cls._ST_UNCONFIGURED:
-        continue
-      used_devs[minor] = state, line
-
-    return used_devs
-
-  def _SetFromMinor(self, minor):
-    """Set our parameters based on the given minor.
-
-    This sets our minor variable and our dev_path.
-
-    """
-    if minor is None:
-      self.minor = self.dev_path = None
-      self.attached = False
-    else:
-      self.minor = minor
-      self.dev_path = self._DevPath(minor)
-      self.attached = True
-
-  @staticmethod
-  def _CheckMetaSize(meta_device):
-    """Check if the given meta device looks like a valid one.
-
-    This currently only checks the size, which must be around
-    128MiB.
-
-    """
-    result = utils.RunCmd(["blockdev", "--getsize", meta_device])
-    if result.failed:
-      _ThrowError("Failed to get device size: %s - %s",
-                  result.fail_reason, result.output)
-    try:
-      sectors = int(result.stdout)
-    except (TypeError, ValueError):
-      _ThrowError("Invalid output from blockdev: '%s'", result.stdout)
-    num_bytes = sectors * 512
-    if num_bytes < 128 * 1024 * 1024: # less than 128MiB
-      _ThrowError("Meta device too small (%.2fMib)", (num_bytes / 1024 / 1024))
-    # the maximum *valid* size of the meta device when living on top
-    # of LVM is hard to compute: it depends on the number of stripes
-    # and the PE size; e.g. a 2-stripe, 64MB PE will result in a 128MB
-    # (normal size), but an eight-stripe 128MB PE will result in a 1GB
-    # size meta device; as such, we restrict it to 1GB (a little bit
-    # too generous, but making assumptions about PE size is hard)
-    if num_bytes > 1024 * 1024 * 1024:
-      _ThrowError("Meta device too big (%.2fMiB)", (num_bytes / 1024 / 1024))
-
-  def Rename(self, new_id):
-    """Rename a device.
-
-    This is not supported for drbd devices.
-
-    """
-    raise errors.ProgrammerError("Can't rename a drbd device")
-
-
-class DRBD8(BaseDRBD):
-  """DRBD v8.x block device.
-
-  This implements the local host part of the DRBD device, i.e. it
-  doesn't do anything to the supposed peer. If you need a fully
-  connected DRBD pair, you need to use this class on both hosts.
-
-  The unique_id for the drbd device is a (local_ip, local_port,
-  remote_ip, remote_port, local_minor, secret) tuple, and it must have
-  two children: the data device and the meta_device. The meta device
-  is checked for valid size and is zeroed on create.
-
-  """
-  _MAX_MINORS = 255
-  _PARSE_SHOW = None
-
-  # timeout constants
-  _NET_RECONFIG_TIMEOUT = 60
-
-  # command line options for barriers
-  _DISABLE_DISK_OPTION = "--no-disk-barrier"  # -a
-  _DISABLE_DRAIN_OPTION = "--no-disk-drain"   # -D
-  _DISABLE_FLUSH_OPTION = "--no-disk-flushes" # -i
-  _DISABLE_META_FLUSH_OPTION = "--no-md-flushes"  # -m
-
-  def __init__(self, unique_id, children, size, params):
-    if children and children.count(None) > 0:
-      children = []
-    if len(children) not in (0, 2):
-      raise ValueError("Invalid configuration data %s" % str(children))
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 6:
-      raise ValueError("Invalid configuration data %s" % str(unique_id))
-    (self._lhost, self._lport,
-     self._rhost, self._rport,
-     self._aminor, self._secret) = unique_id
-    if children:
-      if not _CanReadDevice(children[1].dev_path):
-        logging.info("drbd%s: Ignoring unreadable meta device", self._aminor)
-        children = []
-    super(DRBD8, self).__init__(unique_id, children, size, params)
-    self.major = self._DRBD_MAJOR
-    version = self._GetVersion(self._GetProcData())
-    if version["k_major"] != 8:
-      _ThrowError("Mismatch in DRBD kernel version and requested ganeti"
-                  " usage: kernel is %s.%s, ganeti wants 8.x",
-                  version["k_major"], version["k_minor"])
-
-    if (self._lhost is not None and self._lhost == self._rhost and
-        self._lport == self._rport):
-      raise ValueError("Invalid configuration data, same local/remote %s" %
-                       (unique_id,))
-    self.Attach()
-
-  @classmethod
-  def _InitMeta(cls, minor, dev_path):
-    """Initialize a meta device.
-
-    This will not work if the given minor is in use.
-
-    """
-    # Zero the metadata first, in order to make sure drbdmeta doesn't
-    # try to auto-detect existing filesystems or similar (see
-    # http://code.google.com/p/ganeti/issues/detail?id=182); we only
-    # care about the first 128MB of data in the device, even though it
-    # can be bigger
-    result = utils.RunCmd([constants.DD_CMD,
-                           "if=/dev/zero", "of=%s" % dev_path,
-                           "bs=1048576", "count=128", "oflag=direct"])
-    if result.failed:
-      _ThrowError("Can't wipe the meta device: %s", result.output)
-
-    result = utils.RunCmd(["drbdmeta", "--force", cls._DevPath(minor),
-                           "v08", dev_path, "0", "create-md"])
-    if result.failed:
-      _ThrowError("Can't initialize meta device: %s", result.output)
-
-  @classmethod
-  def _FindUnusedMinor(cls):
-    """Find an unused DRBD device.
-
-    This is specific to 8.x as the minors are allocated dynamically,
-    so non-existing numbers up to a max minor count are actually free.
-
-    """
-    data = cls._GetProcData()
-
-    highest = None
-    for line in data:
-      match = cls._UNUSED_LINE_RE.match(line)
-      if match:
-        return int(match.group(1))
-      match = cls._VALID_LINE_RE.match(line)
-      if match:
-        minor = int(match.group(1))
-        highest = max(highest, minor)
-    if highest is None: # there are no minors in use at all
-      return 0
-    if highest >= cls._MAX_MINORS:
-      logging.error("Error: no free drbd minors!")
-      raise errors.BlockDeviceError("Can't find a free DRBD minor")
-    return highest + 1
-
-  @classmethod
-  def _GetShowParser(cls):
-    """Return a parser for `drbd show` output.
-
-    This will either create or return an already-created parser for the
-    output of the command `drbd show`.
-
-    """
-    if cls._PARSE_SHOW is not None:
-      return cls._PARSE_SHOW
-
-    # pyparsing setup
-    lbrace = pyp.Literal("{").suppress()
-    rbrace = pyp.Literal("}").suppress()
-    lbracket = pyp.Literal("[").suppress()
-    rbracket = pyp.Literal("]").suppress()
-    semi = pyp.Literal(";").suppress()
-    colon = pyp.Literal(":").suppress()
-    # this also converts the value to an int
-    number = pyp.Word(pyp.nums).setParseAction(lambda s, l, t: int(t[0]))
-
-    comment = pyp.Literal("#") + pyp.Optional(pyp.restOfLine)
-    defa = pyp.Literal("_is_default").suppress()
-    dbl_quote = pyp.Literal('"').suppress()
-
-    keyword = pyp.Word(pyp.alphanums + "-")
-
-    # value types
-    value = pyp.Word(pyp.alphanums + "_-/.:")
-    quoted = dbl_quote + pyp.CharsNotIn('"') + dbl_quote
-    ipv4_addr = (pyp.Optional(pyp.Literal("ipv4")).suppress() +
-                 pyp.Word(pyp.nums + ".") + colon + number)
-    ipv6_addr = (pyp.Optional(pyp.Literal("ipv6")).suppress() +
-                 pyp.Optional(lbracket) + pyp.Word(pyp.hexnums + ":") +
-                 pyp.Optional(rbracket) + colon + number)
-    # meta device, extended syntax
-    meta_value = ((value ^ quoted) + lbracket + number + rbracket)
-    # device name, extended syntax
-    device_value = pyp.Literal("minor").suppress() + number
-
-    # a statement
-    stmt = (~rbrace + keyword + ~lbrace +
-            pyp.Optional(ipv4_addr ^ ipv6_addr ^ value ^ quoted ^ meta_value ^
-                         device_value) +
-            pyp.Optional(defa) + semi +
-            pyp.Optional(pyp.restOfLine).suppress())
-
-    # an entire section
-    section_name = pyp.Word(pyp.alphas + "_")
-    section = section_name + lbrace + pyp.ZeroOrMore(pyp.Group(stmt)) + rbrace
-
-    bnf = pyp.ZeroOrMore(pyp.Group(section ^ stmt))
-    bnf.ignore(comment)
-
-    cls._PARSE_SHOW = bnf
-
-    return bnf
-
-  @classmethod
-  def _GetShowData(cls, minor):
-    """Return the `drbdsetup show` data for a minor.
-
-    """
-    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "show"])
-    if result.failed:
-      logging.error("Can't display the drbd config: %s - %s",
-                    result.fail_reason, result.output)
-      return None
-    return result.stdout
-
-  @classmethod
-  def _GetDevInfo(cls, out):
-    """Parse details about a given DRBD minor.
-
-    This return, if available, the local backing device (as a path)
-    and the local and remote (ip, port) information from a string
-    containing the output of the `drbdsetup show` command as returned
-    by _GetShowData.
-
-    """
-    data = {}
-    if not out:
-      return data
-
-    bnf = cls._GetShowParser()
-    # run pyparse
-
-    try:
-      results = bnf.parseString(out)
-    except pyp.ParseException, err:
-      _ThrowError("Can't parse drbdsetup show output: %s", str(err))
-
-    # and massage the results into our desired format
-    for section in results:
-      sname = section[0]
-      if sname == "_this_host":
-        for lst in section[1:]:
-          if lst[0] == "disk":
-            data["local_dev"] = lst[1]
-          elif lst[0] == "meta-disk":
-            data["meta_dev"] = lst[1]
-            data["meta_index"] = lst[2]
-          elif lst[0] == "address":
-            data["local_addr"] = tuple(lst[1:])
-      elif sname == "_remote_host":
-        for lst in section[1:]:
-          if lst[0] == "address":
-            data["remote_addr"] = tuple(lst[1:])
-    return data
-
-  def _MatchesLocal(self, info):
-    """Test if our local config matches with an existing device.
-
-    The parameter should be as returned from `_GetDevInfo()`. This
-    method tests if our local backing device is the same as the one in
-    the info parameter, in effect testing if we look like the given
-    device.
-
-    """
-    if self._children:
-      backend, meta = self._children
-    else:
-      backend = meta = None
-
-    if backend is not None:
-      retval = ("local_dev" in info and info["local_dev"] == backend.dev_path)
-    else:
-      retval = ("local_dev" not in info)
-
-    if meta is not None:
-      retval = retval and ("meta_dev" in info and
-                           info["meta_dev"] == meta.dev_path)
-      retval = retval and ("meta_index" in info and
-                           info["meta_index"] == 0)
-    else:
-      retval = retval and ("meta_dev" not in info and
-                           "meta_index" not in info)
-    return retval
-
-  def _MatchesNet(self, info):
-    """Test if our network config matches with an existing device.
-
-    The parameter should be as returned from `_GetDevInfo()`. This
-    method tests if our network configuration is the same as the one
-    in the info parameter, in effect testing if we look like the given
-    device.
-
-    """
-    if (((self._lhost is None and not ("local_addr" in info)) and
-         (self._rhost is None and not ("remote_addr" in info)))):
-      return True
-
-    if self._lhost is None:
-      return False
-
-    if not ("local_addr" in info and
-            "remote_addr" in info):
-      return False
-
-    retval = (info["local_addr"] == (self._lhost, self._lport))
-    retval = (retval and
-              info["remote_addr"] == (self._rhost, self._rport))
-    return retval
-
-  def _AssembleLocal(self, minor, backend, meta, size):
-    """Configure the local part of a DRBD device.
-
-    """
-    args = ["drbdsetup", self._DevPath(minor), "disk",
-            backend, meta, "0",
-            "-e", "detach",
-            "--create-device"]
-    if size:
-      args.extend(["-d", "%sm" % size])
-
-    version = self._GetVersion(self._GetProcData())
-    vmaj = version["k_major"]
-    vmin = version["k_minor"]
-    vrel = version["k_point"]
-
-    barrier_args = \
-      self._ComputeDiskBarrierArgs(vmaj, vmin, vrel,
-                                   self.params[constants.LDP_BARRIERS],
-                                   self.params[constants.LDP_NO_META_FLUSH])
-    args.extend(barrier_args)
-
-    if self.params[constants.LDP_DISK_CUSTOM]:
-      args.extend(shlex.split(self.params[constants.LDP_DISK_CUSTOM]))
-
-    result = utils.RunCmd(args)
-    if result.failed:
-      _ThrowError("drbd%d: can't attach local disk: %s", minor, result.output)
-
-  @classmethod
-  def _ComputeDiskBarrierArgs(cls, vmaj, vmin, vrel, disabled_barriers,
-                              disable_meta_flush):
-    """Compute the DRBD command line parameters for disk barriers
-
-    Returns a list of the disk barrier parameters as requested via the
-    disabled_barriers and disable_meta_flush arguments, and according to the
-    supported ones in the DRBD version vmaj.vmin.vrel
-
-    If the desired option is unsupported, raises errors.BlockDeviceError.
-
-    """
-    disabled_barriers_set = frozenset(disabled_barriers)
-    if not disabled_barriers_set in constants.DRBD_VALID_BARRIER_OPT:
-      raise errors.BlockDeviceError("%s is not a valid option set for DRBD"
-                                    " barriers" % disabled_barriers)
-
-    args = []
-
-    # The following code assumes DRBD 8.x, with x < 4 and x != 1 (DRBD 8.1.x
-    # does not exist)
-    if not vmaj == 8 and vmin in (0, 2, 3):
-      raise errors.BlockDeviceError("Unsupported DRBD version: %d.%d.%d" %
-                                    (vmaj, vmin, vrel))
-
-    def _AppendOrRaise(option, min_version):
-      """Helper for DRBD options"""
-      if min_version is not None and vrel >= min_version:
-        args.append(option)
-      else:
-        raise errors.BlockDeviceError("Could not use the option %s as the"
-                                      " DRBD version %d.%d.%d does not support"
-                                      " it." % (option, vmaj, vmin, vrel))
-
-    # the minimum version for each feature is encoded via pairs of (minor
-    # version -> x) where x is version in which support for the option was
-    # introduced.
-    meta_flush_supported = disk_flush_supported = {
-      0: 12,
-      2: 7,
-      3: 0,
-      }
-
-    disk_drain_supported = {
-      2: 7,
-      3: 0,
-      }
-
-    disk_barriers_supported = {
-      3: 0,
-      }
-
-    # meta flushes
-    if disable_meta_flush:
-      _AppendOrRaise(cls._DISABLE_META_FLUSH_OPTION,
-                     meta_flush_supported.get(vmin, None))
-
-    # disk flushes
-    if constants.DRBD_B_DISK_FLUSH in disabled_barriers_set:
-      _AppendOrRaise(cls._DISABLE_FLUSH_OPTION,
-                     disk_flush_supported.get(vmin, None))
-
-    # disk drain
-    if constants.DRBD_B_DISK_DRAIN in disabled_barriers_set:
-      _AppendOrRaise(cls._DISABLE_DRAIN_OPTION,
-                     disk_drain_supported.get(vmin, None))
-
-    # disk barriers
-    if constants.DRBD_B_DISK_BARRIERS in disabled_barriers_set:
-      _AppendOrRaise(cls._DISABLE_DISK_OPTION,
-                     disk_barriers_supported.get(vmin, None))
-
-    return args
-
-  def _AssembleNet(self, minor, net_info, protocol,
-                   dual_pri=False, hmac=None, secret=None):
-    """Configure the network part of the device.
-
-    """
-    lhost, lport, rhost, rport = net_info
-    if None in net_info:
-      # we don't want network connection and actually want to make
-      # sure its shutdown
-      self._ShutdownNet(minor)
-      return
-
-    # Workaround for a race condition. When DRBD is doing its dance to
-    # establish a connection with its peer, it also sends the
-    # synchronization speed over the wire. In some cases setting the
-    # sync speed only after setting up both sides can race with DRBD
-    # connecting, hence we set it here before telling DRBD anything
-    # about its peer.
-    sync_errors = self._SetMinorSyncParams(minor, self.params)
-    if sync_errors:
-      _ThrowError("drbd%d: can't set the synchronization parameters: %s" %
-                  (minor, utils.CommaJoin(sync_errors)))
-
-    if netutils.IP6Address.IsValid(lhost):
-      if not netutils.IP6Address.IsValid(rhost):
-        _ThrowError("drbd%d: can't connect ip %s to ip %s" %
-                    (minor, lhost, rhost))
-      family = "ipv6"
-    elif netutils.IP4Address.IsValid(lhost):
-      if not netutils.IP4Address.IsValid(rhost):
-        _ThrowError("drbd%d: can't connect ip %s to ip %s" %
-                    (minor, lhost, rhost))
-      family = "ipv4"
-    else:
-      _ThrowError("drbd%d: Invalid ip %s" % (minor, lhost))
-
-    args = ["drbdsetup", self._DevPath(minor), "net",
-            "%s:%s:%s" % (family, lhost, lport),
-            "%s:%s:%s" % (family, rhost, rport), protocol,
-            "-A", "discard-zero-changes",
-            "-B", "consensus",
-            "--create-device",
-            ]
-    if dual_pri:
-      args.append("-m")
-    if hmac and secret:
-      args.extend(["-a", hmac, "-x", secret])
-
-    if self.params[constants.LDP_NET_CUSTOM]:
-      args.extend(shlex.split(self.params[constants.LDP_NET_CUSTOM]))
-
-    result = utils.RunCmd(args)
-    if result.failed:
-      _ThrowError("drbd%d: can't setup network: %s - %s",
-                  minor, result.fail_reason, result.output)
-
-    def _CheckNetworkConfig():
-      info = self._GetDevInfo(self._GetShowData(minor))
-      if not "local_addr" in info or not "remote_addr" in info:
-        raise utils.RetryAgain()
-
-      if (info["local_addr"] != (lhost, lport) or
-          info["remote_addr"] != (rhost, rport)):
-        raise utils.RetryAgain()
-
-    try:
-      utils.Retry(_CheckNetworkConfig, 1.0, 10.0)
-    except utils.RetryTimeout:
-      _ThrowError("drbd%d: timeout while configuring network", minor)
-
-  def AddChildren(self, devices):
-    """Add a disk to the DRBD device.
-
-    """
-    if self.minor is None:
-      _ThrowError("drbd%d: can't attach to dbrd8 during AddChildren",
-                  self._aminor)
-    if len(devices) != 2:
-      _ThrowError("drbd%d: need two devices for AddChildren", self.minor)
-    info = self._GetDevInfo(self._GetShowData(self.minor))
-    if "local_dev" in info:
-      _ThrowError("drbd%d: already attached to a local disk", self.minor)
-    backend, meta = devices
-    if backend.dev_path is None or meta.dev_path is None:
-      _ThrowError("drbd%d: children not ready during AddChildren", self.minor)
-    backend.Open()
-    meta.Open()
-    self._CheckMetaSize(meta.dev_path)
-    self._InitMeta(self._FindUnusedMinor(), meta.dev_path)
-
-    self._AssembleLocal(self.minor, backend.dev_path, meta.dev_path, self.size)
-    self._children = devices
-
-  def RemoveChildren(self, devices):
-    """Detach the drbd device from local storage.
-
-    """
-    if self.minor is None:
-      _ThrowError("drbd%d: can't attach to drbd8 during RemoveChildren",
-                  self._aminor)
-    # early return if we don't actually have backing storage
-    info = self._GetDevInfo(self._GetShowData(self.minor))
-    if "local_dev" not in info:
-      return
-    if len(self._children) != 2:
-      _ThrowError("drbd%d: we don't have two children: %s", self.minor,
-                  self._children)
-    if self._children.count(None) == 2: # we don't actually have children :)
-      logging.warning("drbd%d: requested detach while detached", self.minor)
-      return
-    if len(devices) != 2:
-      _ThrowError("drbd%d: we need two children in RemoveChildren", self.minor)
-    for child, dev in zip(self._children, devices):
-      if dev != child.dev_path:
-        _ThrowError("drbd%d: mismatch in local storage (%s != %s) in"
-                    " RemoveChildren", self.minor, dev, child.dev_path)
-
-    self._ShutdownLocal(self.minor)
-    self._children = []
-
-  @classmethod
-  def _SetMinorSyncParams(cls, minor, params):
-    """Set the parameters of the DRBD syncer.
-
-    This is the low-level implementation.
-
-    @type minor: int
-    @param minor: the drbd minor whose settings we change
-    @type params: dict
-    @param params: LD level disk parameters related to the synchronization
-    @rtype: list
-    @return: a list of error messages
-
-    """
-
-    args = ["drbdsetup", cls._DevPath(minor), "syncer"]
-    if params[constants.LDP_DYNAMIC_RESYNC]:
-      version = cls._GetVersion(cls._GetProcData())
-      vmin = version["k_minor"]
-      vrel = version["k_point"]
-
-      # By definition we are using 8.x, so just check the rest of the version
-      # number
-      if vmin != 3 or vrel < 9:
-        msg = ("The current DRBD version (8.%d.%d) does not support the "
-               "dynamic resync speed controller" % (vmin, vrel))
-        logging.error(msg)
-        return [msg]
-
-      if params[constants.LDP_PLAN_AHEAD] == 0:
-        msg = ("A value of 0 for c-plan-ahead disables the dynamic sync speed"
-               " controller at DRBD level. If you want to disable it, please"
-               " set the dynamic-resync disk parameter to False.")
-        logging.error(msg)
-        return [msg]
-
-      # add the c-* parameters to args
-      args.extend(["--c-plan-ahead", params[constants.LDP_PLAN_AHEAD],
-                   "--c-fill-target", params[constants.LDP_FILL_TARGET],
-                   "--c-delay-target", params[constants.LDP_DELAY_TARGET],
-                   "--c-max-rate", params[constants.LDP_MAX_RATE],
-                   "--c-min-rate", params[constants.LDP_MIN_RATE],
-                   ])
-
-    else:
-      args.extend(["-r", "%d" % params[constants.LDP_RESYNC_RATE]])
-
-    args.append("--create-device")
-    result = utils.RunCmd(args)
-    if result.failed:
-      msg = ("Can't change syncer rate: %s - %s" %
-             (result.fail_reason, result.output))
-      logging.error(msg)
-      return [msg]
-
-    return []
-
-  def SetSyncParams(self, params):
-    """Set the synchronization parameters of the DRBD syncer.
-
-    @type params: dict
-    @param params: LD level disk parameters related to the synchronization
-    @rtype: list
-    @return: a list of error messages, emitted both by the current node and by
-    children. An empty list means no errors
-
-    """
-    if self.minor is None:
-      err = "Not attached during SetSyncParams"
-      logging.info(err)
-      return [err]
-
-    children_result = super(DRBD8, self).SetSyncParams(params)
-    children_result.extend(self._SetMinorSyncParams(self.minor, params))
-    return children_result
-
-  def PauseResumeSync(self, pause):
-    """Pauses or resumes the sync of a DRBD device.
-
-    @param pause: Wether to pause or resume
-    @return: the success of the operation
-
-    """
-    if self.minor is None:
-      logging.info("Not attached during PauseSync")
-      return False
-
-    children_result = super(DRBD8, self).PauseResumeSync(pause)
-
-    if pause:
-      cmd = "pause-sync"
-    else:
-      cmd = "resume-sync"
-
-    result = utils.RunCmd(["drbdsetup", self.dev_path, cmd])
-    if result.failed:
-      logging.error("Can't %s: %s - %s", cmd,
-                    result.fail_reason, result.output)
-    return not result.failed and children_result
-
-  def GetProcStatus(self):
-    """Return device data from /proc.
-
-    """
-    if self.minor is None:
-      _ThrowError("drbd%d: GetStats() called while not attached", self._aminor)
-    proc_info = self._MassageProcData(self._GetProcData())
-    if self.minor not in proc_info:
-      _ThrowError("drbd%d: can't find myself in /proc", self.minor)
-    return DRBD8Status(proc_info[self.minor])
-
-  def GetSyncStatus(self):
-    """Returns the sync status of the device.
-
-
-    If sync_percent is None, it means all is ok
-    If estimated_time is None, it means we can't estimate
-    the time needed, otherwise it's the time left in seconds.
-
-
-    We set the is_degraded parameter to True on two conditions:
-    network not connected or local disk missing.
-
-    We compute the ldisk parameter based on whether we have a local
-    disk or not.
-
-    @rtype: objects.BlockDevStatus
-
-    """
-    if self.minor is None and not self.Attach():
-      _ThrowError("drbd%d: can't Attach() in GetSyncStatus", self._aminor)
-
-    stats = self.GetProcStatus()
-    is_degraded = not stats.is_connected or not stats.is_disk_uptodate
-
-    if stats.is_disk_uptodate:
-      ldisk_status = constants.LDS_OKAY
-    elif stats.is_diskless:
-      ldisk_status = constants.LDS_FAULTY
-    else:
-      ldisk_status = constants.LDS_UNKNOWN
-
-    return objects.BlockDevStatus(dev_path=self.dev_path,
-                                  major=self.major,
-                                  minor=self.minor,
-                                  sync_percent=stats.sync_percent,
-                                  estimated_time=stats.est_time,
-                                  is_degraded=is_degraded,
-                                  ldisk_status=ldisk_status)
-
-  def Open(self, force=False):
-    """Make the local state primary.
-
-    If the 'force' parameter is given, the '-o' option is passed to
-    drbdsetup. Since this is a potentially dangerous operation, the
-    force flag should be only given after creation, when it actually
-    is mandatory.
-
-    """
-    if self.minor is None and not self.Attach():
-      logging.error("DRBD cannot attach to a device during open")
-      return False
-    cmd = ["drbdsetup", self.dev_path, "primary"]
-    if force:
-      cmd.append("-o")
-    result = utils.RunCmd(cmd)
-    if result.failed:
-      _ThrowError("drbd%d: can't make drbd device primary: %s", self.minor,
-                  result.output)
-
-  def Close(self):
-    """Make the local state secondary.
-
-    This will, of course, fail if the device is in use.
-
-    """
-    if self.minor is None and not self.Attach():
-      _ThrowError("drbd%d: can't Attach() in Close()", self._aminor)
-    result = utils.RunCmd(["drbdsetup", self.dev_path, "secondary"])
-    if result.failed:
-      _ThrowError("drbd%d: can't switch drbd device to secondary: %s",
-                  self.minor, result.output)
-
-  def DisconnectNet(self):
-    """Removes network configuration.
-
-    This method shutdowns the network side of the device.
-
-    The method will wait up to a hardcoded timeout for the device to
-    go into standalone after the 'disconnect' command before
-    re-configuring it, as sometimes it takes a while for the
-    disconnect to actually propagate and thus we might issue a 'net'
-    command while the device is still connected. If the device will
-    still be attached to the network and we time out, we raise an
-    exception.
-
-    """
-    if self.minor is None:
-      _ThrowError("drbd%d: disk not attached in re-attach net", self._aminor)
-
-    if None in (self._lhost, self._lport, self._rhost, self._rport):
-      _ThrowError("drbd%d: DRBD disk missing network info in"
-                  " DisconnectNet()", self.minor)
-
-    class _DisconnectStatus:
-      def __init__(self, ever_disconnected):
-        self.ever_disconnected = ever_disconnected
-
-    dstatus = _DisconnectStatus(_IgnoreError(self._ShutdownNet, self.minor))
-
-    def _WaitForDisconnect():
-      if self.GetProcStatus().is_standalone:
-        return
-
-      # retry the disconnect, it seems possible that due to a well-time
-      # disconnect on the peer, my disconnect command might be ignored and
-      # forgotten
-      dstatus.ever_disconnected = \
-        _IgnoreError(self._ShutdownNet, self.minor) or dstatus.ever_disconnected
-
-      raise utils.RetryAgain()
-
-    # Keep start time
-    start_time = time.time()
-
-    try:
-      # Start delay at 100 milliseconds and grow up to 2 seconds
-      utils.Retry(_WaitForDisconnect, (0.1, 1.5, 2.0),
-                  self._NET_RECONFIG_TIMEOUT)
-    except utils.RetryTimeout:
-      if dstatus.ever_disconnected:
-        msg = ("drbd%d: device did not react to the"
-               " 'disconnect' command in a timely manner")
-      else:
-        msg = "drbd%d: can't shutdown network, even after multiple retries"
-
-      _ThrowError(msg, self.minor)
-
-    reconfig_time = time.time() - start_time
-    if reconfig_time > (self._NET_RECONFIG_TIMEOUT * 0.25):
-      logging.info("drbd%d: DisconnectNet: detach took %.3f seconds",
-                   self.minor, reconfig_time)
-
-  def AttachNet(self, multimaster):
-    """Reconnects the network.
-
-    This method connects the network side of the device with a
-    specified multi-master flag. The device needs to be 'Standalone'
-    but have valid network configuration data.
-
-    Args:
-      - multimaster: init the network in dual-primary mode
-
-    """
-    if self.minor is None:
-      _ThrowError("drbd%d: device not attached in AttachNet", self._aminor)
-
-    if None in (self._lhost, self._lport, self._rhost, self._rport):
-      _ThrowError("drbd%d: missing network info in AttachNet()", self.minor)
-
-    status = self.GetProcStatus()
-
-    if not status.is_standalone:
-      _ThrowError("drbd%d: device is not standalone in AttachNet", self.minor)
-
-    self._AssembleNet(self.minor,
-                      (self._lhost, self._lport, self._rhost, self._rport),
-                      constants.DRBD_NET_PROTOCOL, dual_pri=multimaster,
-                      hmac=constants.DRBD_HMAC_ALG, secret=self._secret)
-
-  def Attach(self):
-    """Check if our minor is configured.
-
-    This doesn't do any device configurations - it only checks if the
-    minor is in a state different from Unconfigured.
-
-    Note that this function will not change the state of the system in
-    any way (except in case of side-effects caused by reading from
-    /proc).
-
-    """
-    used_devs = self.GetUsedDevs()
-    if self._aminor in used_devs:
-      minor = self._aminor
-    else:
-      minor = None
-
-    self._SetFromMinor(minor)
-    return minor is not None
-
-  def Assemble(self):
-    """Assemble the drbd.
-
-    Method:
-      - if we have a configured device, we try to ensure that it matches
-        our config
-      - if not, we create it from zero
-      - anyway, set the device parameters
-
-    """
-    super(DRBD8, self).Assemble()
-
-    self.Attach()
-    if self.minor is None:
-      # local device completely unconfigured
-      self._FastAssemble()
-    else:
-      # we have to recheck the local and network status and try to fix
-      # the device
-      self._SlowAssemble()
-
-    sync_errors = self.SetSyncParams(self.params)
-    if sync_errors:
-      _ThrowError("drbd%d: can't set the synchronization parameters: %s" %
-                  (self.minor, utils.CommaJoin(sync_errors)))
-
-  def _SlowAssemble(self):
-    """Assembles the DRBD device from a (partially) configured device.
-
-    In case of partially attached (local device matches but no network
-    setup), we perform the network attach. If successful, we re-test
-    the attach if can return success.
-
-    """
-    # TODO: Rewrite to not use a for loop just because there is 'break'
-    # pylint: disable=W0631
-    net_data = (self._lhost, self._lport, self._rhost, self._rport)
-    for minor in (self._aminor,):
-      info = self._GetDevInfo(self._GetShowData(minor))
-      match_l = self._MatchesLocal(info)
-      match_r = self._MatchesNet(info)
-
-      if match_l and match_r:
-        # everything matches
-        break
-
-      if match_l and not match_r and "local_addr" not in info:
-        # disk matches, but not attached to network, attach and recheck
-        self._AssembleNet(minor, net_data, constants.DRBD_NET_PROTOCOL,
-                          hmac=constants.DRBD_HMAC_ALG, secret=self._secret)
-        if self._MatchesNet(self._GetDevInfo(self._GetShowData(minor))):
-          break
-        else:
-          _ThrowError("drbd%d: network attach successful, but 'drbdsetup"
-                      " show' disagrees", minor)
-
-      if match_r and "local_dev" not in info:
-        # no local disk, but network attached and it matches
-        self._AssembleLocal(minor, self._children[0].dev_path,
-                            self._children[1].dev_path, self.size)
-        if self._MatchesNet(self._GetDevInfo(self._GetShowData(minor))):
-          break
-        else:
-          _ThrowError("drbd%d: disk attach successful, but 'drbdsetup"
-                      " show' disagrees", minor)
-
-      # this case must be considered only if we actually have local
-      # storage, i.e. not in diskless mode, because all diskless
-      # devices are equal from the point of view of local
-      # configuration
-      if (match_l and "local_dev" in info and
-          not match_r and "local_addr" in info):
-        # strange case - the device network part points to somewhere
-        # else, even though its local storage is ours; as we own the
-        # drbd space, we try to disconnect from the remote peer and
-        # reconnect to our correct one
-        try:
-          self._ShutdownNet(minor)
-        except errors.BlockDeviceError, err:
-          _ThrowError("drbd%d: device has correct local storage, wrong"
-                      " remote peer and is unable to disconnect in order"
-                      " to attach to the correct peer: %s", minor, str(err))
-        # note: _AssembleNet also handles the case when we don't want
-        # local storage (i.e. one or more of the _[lr](host|port) is
-        # None)
-        self._AssembleNet(minor, net_data, constants.DRBD_NET_PROTOCOL,
-                          hmac=constants.DRBD_HMAC_ALG, secret=self._secret)
-        if self._MatchesNet(self._GetDevInfo(self._GetShowData(minor))):
-          break
-        else:
-          _ThrowError("drbd%d: network attach successful, but 'drbdsetup"
-                      " show' disagrees", minor)
-
-    else:
-      minor = None
-
-    self._SetFromMinor(minor)
-    if minor is None:
-      _ThrowError("drbd%d: cannot activate, unknown or unhandled reason",
-                  self._aminor)
-
-  def _FastAssemble(self):
-    """Assemble the drbd device from zero.
-
-    This is run when in Assemble we detect our minor is unused.
-
-    """
-    minor = self._aminor
-    if self._children and self._children[0] and self._children[1]:
-      self._AssembleLocal(minor, self._children[0].dev_path,
-                          self._children[1].dev_path, self.size)
-    if self._lhost and self._lport and self._rhost and self._rport:
-      self._AssembleNet(minor,
-                        (self._lhost, self._lport, self._rhost, self._rport),
-                        constants.DRBD_NET_PROTOCOL,
-                        hmac=constants.DRBD_HMAC_ALG, secret=self._secret)
-    self._SetFromMinor(minor)
-
-  @classmethod
-  def _ShutdownLocal(cls, minor):
-    """Detach from the local device.
-
-    I/Os will continue to be served from the remote device. If we
-    don't have a remote device, this operation will fail.
-
-    """
-    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "detach"])
-    if result.failed:
-      _ThrowError("drbd%d: can't detach local disk: %s", minor, result.output)
-
-  @classmethod
-  def _ShutdownNet(cls, minor):
-    """Disconnect from the remote peer.
-
-    This fails if we don't have a local device.
-
-    """
-    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "disconnect"])
-    if result.failed:
-      _ThrowError("drbd%d: can't shutdown network: %s", minor, result.output)
-
-  @classmethod
-  def _ShutdownAll(cls, minor):
-    """Deactivate the device.
-
-    This will, of course, fail if the device is in use.
-
-    """
-    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "down"])
-    if result.failed:
-      _ThrowError("drbd%d: can't shutdown drbd device: %s",
-                  minor, result.output)
-
-  def Shutdown(self):
-    """Shutdown the DRBD device.
-
-    """
-    if self.minor is None and not self.Attach():
-      logging.info("drbd%d: not attached during Shutdown()", self._aminor)
-      return
-    minor = self.minor
-    self.minor = None
-    self.dev_path = None
-    self._ShutdownAll(minor)
-
-  def Remove(self):
-    """Stub remove for DRBD devices.
-
-    """
-    self.Shutdown()
-
-  @classmethod
-  def Create(cls, unique_id, children, size, params, excl_stor):
-    """Create a new DRBD8 device.
-
-    Since DRBD devices are not created per se, just assembled, this
-    function only initializes the metadata.
-
-    """
-    if len(children) != 2:
-      raise errors.ProgrammerError("Invalid setup for the drbd device")
-    if excl_stor:
-      raise errors.ProgrammerError("DRBD device requested with"
-                                   " exclusive_storage")
-    # check that the minor is unused
-    aminor = unique_id[4]
-    proc_info = cls._MassageProcData(cls._GetProcData())
-    if aminor in proc_info:
-      status = DRBD8Status(proc_info[aminor])
-      in_use = status.is_in_use
-    else:
-      in_use = False
-    if in_use:
-      _ThrowError("drbd%d: minor is already in use at Create() time", aminor)
-    meta = children[1]
-    meta.Assemble()
-    if not meta.Attach():
-      _ThrowError("drbd%d: can't attach to meta device '%s'",
-                  aminor, meta)
-    cls._CheckMetaSize(meta.dev_path)
-    cls._InitMeta(aminor, meta.dev_path)
-    return cls(unique_id, children, size, params)
-
-  def Grow(self, amount, dryrun, backingstore):
-    """Resize the DRBD device and its backing storage.
-
-    """
-    if self.minor is None:
-      _ThrowError("drbd%d: Grow called while not attached", self._aminor)
-    if len(self._children) != 2 or None in self._children:
-      _ThrowError("drbd%d: cannot grow diskless device", self.minor)
-    self._children[0].Grow(amount, dryrun, backingstore)
-    if dryrun or backingstore:
-      # DRBD does not support dry-run mode and is not backing storage,
-      # so we'll return here
-      return
-    result = utils.RunCmd(["drbdsetup", self.dev_path, "resize", "-s",
-                           "%dm" % (self.size + amount)])
-    if result.failed:
-      _ThrowError("drbd%d: resize failed: %s", self.minor, result.output)
-
-
-class FileStorage(BlockDev):
-  """File device.
-
-  This class represents the a file storage backend device.
-
-  The unique_id for the file device is a (file_driver, file_path) tuple.
-
-  """
-  def __init__(self, unique_id, children, size, params):
-    """Initalizes a file device backend.
-
-    """
-    if children:
-      raise errors.BlockDeviceError("Invalid setup for file device")
-    super(FileStorage, self).__init__(unique_id, children, size, params)
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise ValueError("Invalid configuration data %s" % str(unique_id))
-    self.driver = unique_id[0]
-    self.dev_path = unique_id[1]
-
-    CheckFileStoragePath(self.dev_path)
-
-    self.Attach()
-
-  def Assemble(self):
-    """Assemble the device.
-
-    Checks whether the file device exists, raises BlockDeviceError otherwise.
-
-    """
-    if not os.path.exists(self.dev_path):
-      _ThrowError("File device '%s' does not exist" % self.dev_path)
-
-  def Shutdown(self):
-    """Shutdown the device.
-
-    This is a no-op for the file type, as we don't deactivate
-    the file on shutdown.
-
-    """
-    pass
-
-  def Open(self, force=False):
-    """Make the device ready for I/O.
-
-    This is a no-op for the file type.
-
-    """
-    pass
-
-  def Close(self):
-    """Notifies that the device will no longer be used for I/O.
-
-    This is a no-op for the file type.
-
-    """
-    pass
-
-  def Remove(self):
-    """Remove the file backing the block device.
-
-    @rtype: boolean
-    @return: True if the removal was successful
-
-    """
-    try:
-      os.remove(self.dev_path)
-    except OSError, err:
-      if err.errno != errno.ENOENT:
-        _ThrowError("Can't remove file '%s': %s", self.dev_path, err)
-
-  def Rename(self, new_id):
-    """Renames the file.
-
-    """
-    # TODO: implement rename for file-based storage
-    _ThrowError("Rename is not supported for file-based storage")
-
-  def Grow(self, amount, dryrun, backingstore):
-    """Grow the file
-
-    @param amount: the amount (in mebibytes) to grow with
-
-    """
-    if not backingstore:
-      return
-    # Check that the file exists
-    self.Assemble()
-    current_size = self.GetActualSize()
-    new_size = current_size + amount * 1024 * 1024
-    assert new_size > current_size, "Cannot Grow with a negative amount"
-    # We can't really simulate the growth
-    if dryrun:
-      return
-    try:
-      f = open(self.dev_path, "a+")
-      f.truncate(new_size)
-      f.close()
-    except EnvironmentError, err:
-      _ThrowError("Error in file growth: %", str(err))
-
-  def Attach(self):
-    """Attach to an existing file.
-
-    Check if this file already exists.
-
-    @rtype: boolean
-    @return: True if file exists
-
-    """
-    self.attached = os.path.exists(self.dev_path)
-    return self.attached
-
-  def GetActualSize(self):
-    """Return the actual disk size.
-
-    @note: the device needs to be active when this is called
-
-    """
-    assert self.attached, "BlockDevice not attached in GetActualSize()"
-    try:
-      st = os.stat(self.dev_path)
-      return st.st_size
-    except OSError, err:
-      _ThrowError("Can't stat %s: %s", self.dev_path, err)
-
-  @classmethod
-  def Create(cls, unique_id, children, size, params, excl_stor):
-    """Create a new file.
-
-    @param size: the size of file in MiB
-
-    @rtype: L{bdev.FileStorage}
-    @return: an instance of FileStorage
-
-    """
-    if excl_stor:
-      raise errors.ProgrammerError("FileStorage device requested with"
-                                   " exclusive_storage")
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise ValueError("Invalid configuration data %s" % str(unique_id))
-
-    dev_path = unique_id[1]
-
-    CheckFileStoragePath(dev_path)
-
-    try:
-      fd = os.open(dev_path, os.O_RDWR | os.O_CREAT | os.O_EXCL)
-      f = os.fdopen(fd, "w")
-      f.truncate(size * 1024 * 1024)
-      f.close()
-    except EnvironmentError, err:
-      if err.errno == errno.EEXIST:
-        _ThrowError("File already existing: %s", dev_path)
-      _ThrowError("Error in file creation: %", str(err))
-
-    return FileStorage(unique_id, children, size, params)
-
-
-class PersistentBlockDevice(BlockDev):
-  """A block device with persistent node
-
-  May be either directly attached, or exposed through DM (e.g. dm-multipath).
-  udev helpers are probably required to give persistent, human-friendly
-  names.
-
-  For the time being, pathnames are required to lie under /dev.
-
-  """
-  def __init__(self, unique_id, children, size, params):
-    """Attaches to a static block device.
-
-    The unique_id is a path under /dev.
-
-    """
-    super(PersistentBlockDevice, self).__init__(unique_id, children, size,
-                                                params)
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise ValueError("Invalid configuration data %s" % str(unique_id))
-    self.dev_path = unique_id[1]
-    if not os.path.realpath(self.dev_path).startswith("/dev/"):
-      raise ValueError("Full path '%s' lies outside /dev" %
-                              os.path.realpath(self.dev_path))
-    # TODO: this is just a safety guard checking that we only deal with devices
-    # we know how to handle. In the future this will be integrated with
-    # external storage backends and possible values will probably be collected
-    # from the cluster configuration.
-    if unique_id[0] != constants.BLOCKDEV_DRIVER_MANUAL:
-      raise ValueError("Got persistent block device of invalid type: %s" %
-                       unique_id[0])
-
-    self.major = self.minor = None
-    self.Attach()
-
-  @classmethod
-  def Create(cls, unique_id, children, size, params, excl_stor):
-    """Create a new device
-
-    This is a noop, we only return a PersistentBlockDevice instance
-
-    """
-    if excl_stor:
-      raise errors.ProgrammerError("Persistent block device requested with"
-                                   " exclusive_storage")
-    return PersistentBlockDevice(unique_id, children, 0, params)
-
-  def Remove(self):
-    """Remove a device
-
-    This is a noop
-
-    """
-    pass
-
-  def Rename(self, new_id):
-    """Rename this device.
-
-    """
-    _ThrowError("Rename is not supported for PersistentBlockDev storage")
-
-  def Attach(self):
-    """Attach to an existing block device.
-
-
-    """
-    self.attached = False
-    try:
-      st = os.stat(self.dev_path)
-    except OSError, err:
-      logging.error("Error stat()'ing %s: %s", self.dev_path, str(err))
-      return False
-
-    if not stat.S_ISBLK(st.st_mode):
-      logging.error("%s is not a block device", self.dev_path)
-      return False
-
-    self.major = os.major(st.st_rdev)
-    self.minor = os.minor(st.st_rdev)
-    self.attached = True
-
-    return True
-
-  def Assemble(self):
-    """Assemble the device.
-
-    """
-    pass
-
-  def Shutdown(self):
-    """Shutdown the device.
-
-    """
-    pass
-
-  def Open(self, force=False):
-    """Make the device ready for I/O.
-
-    """
-    pass
-
-  def Close(self):
-    """Notifies that the device will no longer be used for I/O.
-
-    """
-    pass
-
-  def Grow(self, amount, dryrun, backingstore):
-    """Grow the logical volume.
-
-    """
-    _ThrowError("Grow is not supported for PersistentBlockDev storage")
-
-
-class RADOSBlockDevice(BlockDev):
-  """A RADOS Block Device (rbd).
-
-  This class implements the RADOS Block Device for the backend. You need
-  the rbd kernel driver, the RADOS Tools and a working RADOS cluster for
-  this to be functional.
-
-  """
-  def __init__(self, unique_id, children, size, params):
-    """Attaches to an rbd device.
-
-    """
-    super(RADOSBlockDevice, self).__init__(unique_id, children, size, params)
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise ValueError("Invalid configuration data %s" % str(unique_id))
-
-    self.driver, self.rbd_name = unique_id
-
-    self.major = self.minor = None
-    self.Attach()
-
-  @classmethod
-  def Create(cls, unique_id, children, size, params, excl_stor):
-    """Create a new rbd device.
-
-    Provision a new rbd volume inside a RADOS pool.
-
-    """
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise errors.ProgrammerError("Invalid configuration data %s" %
-                                   str(unique_id))
-    if excl_stor:
-      raise errors.ProgrammerError("RBD device requested with"
-                                   " exclusive_storage")
-    rbd_pool = params[constants.LDP_POOL]
-    rbd_name = unique_id[1]
-
-    # Provision a new rbd volume (Image) inside the RADOS cluster.
-    cmd = [constants.RBD_CMD, "create", "-p", rbd_pool,
-           rbd_name, "--size", "%s" % size]
-    result = utils.RunCmd(cmd)
-    if result.failed:
-      _ThrowError("rbd creation failed (%s): %s",
-                  result.fail_reason, result.output)
-
-    return RADOSBlockDevice(unique_id, children, size, params)
-
-  def Remove(self):
-    """Remove the rbd device.
-
-    """
-    rbd_pool = self.params[constants.LDP_POOL]
-    rbd_name = self.unique_id[1]
-
-    if not self.minor and not self.Attach():
-      # The rbd device doesn't exist.
-      return
-
-    # First shutdown the device (remove mappings).
-    self.Shutdown()
-
-    # Remove the actual Volume (Image) from the RADOS cluster.
-    cmd = [constants.RBD_CMD, "rm", "-p", rbd_pool, rbd_name]
-    result = utils.RunCmd(cmd)
-    if result.failed:
-      _ThrowError("Can't remove Volume from cluster with rbd rm: %s - %s",
-                  result.fail_reason, result.output)
-
-  def Rename(self, new_id):
-    """Rename this device.
-
-    """
-    pass
-
-  def Attach(self):
-    """Attach to an existing rbd device.
-
-    This method maps the rbd volume that matches our name with
-    an rbd device and then attaches to this device.
-
-    """
-    self.attached = False
-
-    # Map the rbd volume to a block device under /dev
-    self.dev_path = self._MapVolumeToBlockdev(self.unique_id)
-
-    try:
-      st = os.stat(self.dev_path)
-    except OSError, err:
-      logging.error("Error stat()'ing %s: %s", self.dev_path, str(err))
-      return False
-
-    if not stat.S_ISBLK(st.st_mode):
-      logging.error("%s is not a block device", self.dev_path)
-      return False
-
-    self.major = os.major(st.st_rdev)
-    self.minor = os.minor(st.st_rdev)
-    self.attached = True
-
-    return True
-
-  def _MapVolumeToBlockdev(self, unique_id):
-    """Maps existing rbd volumes to block devices.
-
-    This method should be idempotent if the mapping already exists.
-
-    @rtype: string
-    @return: the block device path that corresponds to the volume
-
-    """
-    pool = self.params[constants.LDP_POOL]
-    name = unique_id[1]
-
-    # Check if the mapping already exists.
-    rbd_dev = self._VolumeToBlockdev(pool, name)
-    if rbd_dev:
-      # The mapping exists. Return it.
-      return rbd_dev
-
-    # The mapping doesn't exist. Create it.
-    map_cmd = [constants.RBD_CMD, "map", "-p", pool, name]
-    result = utils.RunCmd(map_cmd)
-    if result.failed:
-      _ThrowError("rbd map failed (%s): %s",
-                  result.fail_reason, result.output)
-
-    # Find the corresponding rbd device.
-    rbd_dev = self._VolumeToBlockdev(pool, name)
-    if not rbd_dev:
-      _ThrowError("rbd map succeeded, but could not find the rbd block"
-                  " device in output of showmapped, for volume: %s", name)
-
-    # The device was successfully mapped. Return it.
-    return rbd_dev
-
-  @classmethod
-  def _VolumeToBlockdev(cls, pool, volume_name):
-    """Do the 'volume name'-to-'rbd block device' resolving.
-
-    @type pool: string
-    @param pool: RADOS pool to use
-    @type volume_name: string
-    @param volume_name: the name of the volume whose device we search for
-    @rtype: string or None
-    @return: block device path if the volume is mapped, else None
-
-    """
-    try:
-      # Newer versions of the rbd tool support json output formatting. Use it
-      # if available.
-      showmap_cmd = [
-        constants.RBD_CMD,
-        "showmapped",
-        "-p",
-        pool,
-        "--format",
-        "json"
-        ]
-      result = utils.RunCmd(showmap_cmd)
-      if result.failed:
-        logging.error("rbd JSON output formatting returned error (%s): %s,"
-                      "falling back to plain output parsing",
-                      result.fail_reason, result.output)
-        raise RbdShowmappedJsonError
-
-      return cls._ParseRbdShowmappedJson(result.output, volume_name)
-    except RbdShowmappedJsonError:
-      # For older versions of rbd, we have to parse the plain / text output
-      # manually.
-      showmap_cmd = [constants.RBD_CMD, "showmapped", "-p", pool]
-      result = utils.RunCmd(showmap_cmd)
-      if result.failed:
-        _ThrowError("rbd showmapped failed (%s): %s",
-                    result.fail_reason, result.output)
-
-      return cls._ParseRbdShowmappedPlain(result.output, volume_name)
-
-  @staticmethod
-  def _ParseRbdShowmappedJson(output, volume_name):
-    """Parse the json output of `rbd showmapped'.
-
-    This method parses the json output of `rbd showmapped' and returns the rbd
-    block device path (e.g. /dev/rbd0) that matches the given rbd volume.
-
-    @type output: string
-    @param output: the json output of `rbd showmapped'
-    @type volume_name: string
-    @param volume_name: the name of the volume whose device we search for
-    @rtype: string or None
-    @return: block device path if the volume is mapped, else None
-
-    """
-    try:
-      devices = serializer.LoadJson(output)
-    except ValueError, err:
-      _ThrowError("Unable to parse JSON data: %s" % err)
-
-    rbd_dev = None
-    for d in devices.values(): # pylint: disable=E1103
-      try:
-        name = d["name"]
-      except KeyError:
-        _ThrowError("'name' key missing from json object %s", devices)
-
-      if name == volume_name:
-        if rbd_dev is not None:
-          _ThrowError("rbd volume %s is mapped more than once", volume_name)
-
-        rbd_dev = d["device"]
-
-    return rbd_dev
-
-  @staticmethod
-  def _ParseRbdShowmappedPlain(output, volume_name):
-    """Parse the (plain / text) output of `rbd showmapped'.
-
-    This method parses the output of `rbd showmapped' and returns
-    the rbd block device path (e.g. /dev/rbd0) that matches the
-    given rbd volume.
-
-    @type output: string
-    @param output: the plain text output of `rbd showmapped'
-    @type volume_name: string
-    @param volume_name: the name of the volume whose device we search for
-    @rtype: string or None
-    @return: block device path if the volume is mapped, else None
-
-    """
-    allfields = 5
-    volumefield = 2
-    devicefield = 4
-
-    lines = output.splitlines()
-
-    # Try parsing the new output format (ceph >= 0.55).
-    splitted_lines = map(lambda l: l.split(), lines)
-
-    # Check for empty output.
-    if not splitted_lines:
-      return None
-
-    # Check showmapped output, to determine number of fields.
-    field_cnt = len(splitted_lines[0])
-    if field_cnt != allfields:
-      # Parsing the new format failed. Fallback to parsing the old output
-      # format (< 0.55).
-      splitted_lines = map(lambda l: l.split("\t"), lines)
-      if field_cnt != allfields:
-        _ThrowError("Cannot parse rbd showmapped output expected %s fields,"
-                    " found %s", allfields, field_cnt)
-
-    matched_lines = \
-      filter(lambda l: len(l) == allfields and l[volumefield] == volume_name,
-             splitted_lines)
-
-    if len(matched_lines) > 1:
-      _ThrowError("rbd volume %s mapped more than once", volume_name)
-
-    if matched_lines:
-      # rbd block device found. Return it.
-      rbd_dev = matched_lines[0][devicefield]
-      return rbd_dev
-
-    # The given volume is not mapped.
-    return None
-
-  def Assemble(self):
-    """Assemble the device.
-
-    """
-    pass
-
-  def Shutdown(self):
-    """Shutdown the device.
-
-    """
-    if not self.minor and not self.Attach():
-      # The rbd device doesn't exist.
-      return
-
-    # Unmap the block device from the Volume.
-    self._UnmapVolumeFromBlockdev(self.unique_id)
-
-    self.minor = None
-    self.dev_path = None
-
-  def _UnmapVolumeFromBlockdev(self, unique_id):
-    """Unmaps the rbd device from the Volume it is mapped.
-
-    Unmaps the rbd device from the Volume it was previously mapped to.
-    This method should be idempotent if the Volume isn't mapped.
-
-    """
-    pool = self.params[constants.LDP_POOL]
-    name = unique_id[1]
-
-    # Check if the mapping already exists.
-    rbd_dev = self._VolumeToBlockdev(pool, name)
-
-    if rbd_dev:
-      # The mapping exists. Unmap the rbd device.
-      unmap_cmd = [constants.RBD_CMD, "unmap", "%s" % rbd_dev]
-      result = utils.RunCmd(unmap_cmd)
-      if result.failed:
-        _ThrowError("rbd unmap failed (%s): %s",
-                    result.fail_reason, result.output)
-
-  def Open(self, force=False):
-    """Make the device ready for I/O.
-
-    """
-    pass
-
-  def Close(self):
-    """Notifies that the device will no longer be used for I/O.
-
-    """
-    pass
-
-  def Grow(self, amount, dryrun, backingstore):
-    """Grow the Volume.
-
-    @type amount: integer
-    @param amount: the amount (in mebibytes) to grow with
-    @type dryrun: boolean
-    @param dryrun: whether to execute the operation in simulation mode
-        only, without actually increasing the size
-
-    """
-    if not backingstore:
-      return
-    if not self.Attach():
-      _ThrowError("Can't attach to rbd device during Grow()")
-
-    if dryrun:
-      # the rbd tool does not support dry runs of resize operations.
-      # Since rbd volumes are thinly provisioned, we assume
-      # there is always enough free space for the operation.
-      return
-
-    rbd_pool = self.params[constants.LDP_POOL]
-    rbd_name = self.unique_id[1]
-    new_size = self.size + amount
-
-    # Resize the rbd volume (Image) inside the RADOS cluster.
-    cmd = [constants.RBD_CMD, "resize", "-p", rbd_pool,
-           rbd_name, "--size", "%s" % new_size]
-    result = utils.RunCmd(cmd)
-    if result.failed:
-      _ThrowError("rbd resize failed (%s): %s",
-                  result.fail_reason, result.output)
-
-
-class ExtStorageDevice(BlockDev):
-  """A block device provided by an ExtStorage Provider.
-
-  This class implements the External Storage Interface, which means
-  handling of the externally provided block devices.
-
-  """
-  def __init__(self, unique_id, children, size, params):
-    """Attaches to an extstorage block device.
-
-    """
-    super(ExtStorageDevice, self).__init__(unique_id, children, size, params)
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise ValueError("Invalid configuration data %s" % str(unique_id))
-
-    self.driver, self.vol_name = unique_id
-    self.ext_params = params
-
-    self.major = self.minor = None
-    self.Attach()
-
-  @classmethod
-  def Create(cls, unique_id, children, size, params, excl_stor):
-    """Create a new extstorage device.
-
-    Provision a new volume using an extstorage provider, which will
-    then be mapped to a block device.
-
-    """
-    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
-      raise errors.ProgrammerError("Invalid configuration data %s" %
-                                   str(unique_id))
-    if excl_stor:
-      raise errors.ProgrammerError("extstorage device requested with"
-                                   " exclusive_storage")
-
-    # Call the External Storage's create script,
-    # to provision a new Volume inside the External Storage
-    _ExtStorageAction(constants.ES_ACTION_CREATE, unique_id,
-                      params, str(size))
-
-    return ExtStorageDevice(unique_id, children, size, params)
-
-  def Remove(self):
-    """Remove the extstorage device.
-
-    """
-    if not self.minor and not self.Attach():
-      # The extstorage device doesn't exist.
-      return
-
-    # First shutdown the device (remove mappings).
-    self.Shutdown()
-
-    # Call the External Storage's remove script,
-    # to remove the Volume from the External Storage
-    _ExtStorageAction(constants.ES_ACTION_REMOVE, self.unique_id,
-                      self.ext_params)
-
-  def Rename(self, new_id):
-    """Rename this device.
-
-    """
-    pass
-
-  def Attach(self):
-    """Attach to an existing extstorage device.
-
-    This method maps the extstorage volume that matches our name with
-    a corresponding block device and then attaches to this device.
-
-    """
-    self.attached = False
-
-    # Call the External Storage's attach script,
-    # to attach an existing Volume to a block device under /dev
-    self.dev_path = _ExtStorageAction(constants.ES_ACTION_ATTACH,
-                                      self.unique_id, self.ext_params)
-
-    try:
-      st = os.stat(self.dev_path)
-    except OSError, err:
-      logging.error("Error stat()'ing %s: %s", self.dev_path, str(err))
-      return False
-
-    if not stat.S_ISBLK(st.st_mode):
-      logging.error("%s is not a block device", self.dev_path)
-      return False
-
-    self.major = os.major(st.st_rdev)
-    self.minor = os.minor(st.st_rdev)
-    self.attached = True
-
-    return True
-
-  def Assemble(self):
-    """Assemble the device.
-
-    """
-    pass
-
-  def Shutdown(self):
-    """Shutdown the device.
-
-    """
-    if not self.minor and not self.Attach():
-      # The extstorage device doesn't exist.
-      return
-
-    # Call the External Storage's detach script,
-    # to detach an existing Volume from it's block device under /dev
-    _ExtStorageAction(constants.ES_ACTION_DETACH, self.unique_id,
-                      self.ext_params)
-
-    self.minor = None
-    self.dev_path = None
-
-  def Open(self, force=False):
-    """Make the device ready for I/O.
-
-    """
-    pass
-
-  def Close(self):
-    """Notifies that the device will no longer be used for I/O.
-
-    """
-    pass
-
-  def Grow(self, amount, dryrun, backingstore):
-    """Grow the Volume.
-
-    @type amount: integer
-    @param amount: the amount (in mebibytes) to grow with
-    @type dryrun: boolean
-    @param dryrun: whether to execute the operation in simulation mode
-        only, without actually increasing the size
-
-    """
-    if not backingstore:
-      return
-    if not self.Attach():
-      _ThrowError("Can't attach to extstorage device during Grow()")
-
-    if dryrun:
-      # we do not support dry runs of resize operations for now.
-      return
-
-    new_size = self.size + amount
-
-    # Call the External Storage's grow script,
-    # to grow an existing Volume inside the External Storage
-    _ExtStorageAction(constants.ES_ACTION_GROW, self.unique_id,
-                      self.ext_params, str(self.size), grow=str(new_size))
-
-  def SetInfo(self, text):
-    """Update metadata with info text.
-
-    """
-    # Replace invalid characters
-    text = re.sub("^[^A-Za-z0-9_+.]", "_", text)
-    text = re.sub("[^-A-Za-z0-9_+.]", "_", text)
-
-    # Only up to 128 characters are allowed
-    text = text[:128]
-
-    # Call the External Storage's setinfo script,
-    # to set metadata for an existing Volume inside the External Storage
-    _ExtStorageAction(constants.ES_ACTION_SETINFO, self.unique_id,
-                      self.ext_params, metadata=text)
-
-
-def _ExtStorageAction(action, unique_id, ext_params,
-                      size=None, grow=None, metadata=None):
-  """Take an External Storage action.
-
-  Take an External Storage action concerning or affecting
-  a specific Volume inside the External Storage.
-
-  @type action: string
-  @param action: which action to perform. One of:
-                 create / remove / grow / attach / detach
-  @type unique_id: tuple (driver, vol_name)
-  @param unique_id: a tuple containing the type of ExtStorage (driver)
-                    and the Volume name
-  @type ext_params: dict
-  @param ext_params: ExtStorage parameters
-  @type size: integer
-  @param size: the size of the Volume in mebibytes
-  @type grow: integer
-  @param grow: the new size in mebibytes (after grow)
-  @type metadata: string
-  @param metadata: metadata info of the Volume, for use by the provider
-  @rtype: None or a block device path (during attach)
-
-  """
-  driver, vol_name = unique_id
-
-  # Create an External Storage instance of type `driver'
-  status, inst_es = ExtStorageFromDisk(driver)
-  if not status:
-    _ThrowError("%s" % inst_es)
-
-  # Create the basic environment for the driver's scripts
-  create_env = _ExtStorageEnvironment(unique_id, ext_params, size,
-                                      grow, metadata)
-
-  # Do not use log file for action `attach' as we need
-  # to get the output from RunResult
-  # TODO: find a way to have a log file for attach too
-  logfile = None
-  if action is not constants.ES_ACTION_ATTACH:
-    logfile = _VolumeLogName(action, driver, vol_name)
-
-  # Make sure the given action results in a valid script
-  if action not in constants.ES_SCRIPTS:
-    _ThrowError("Action '%s' doesn't result in a valid ExtStorage script" %
-                action)
-
-  # Find out which external script to run according the given action
-  script_name = action + "_script"
-  script = getattr(inst_es, script_name)
-
-  # Run the external script
-  result = utils.RunCmd([script], env=create_env,
-                        cwd=inst_es.path, output=logfile,)
-  if result.failed:
-    logging.error("External storage's %s command '%s' returned"
-                  " error: %s, logfile: %s, output: %s",
-                  action, result.cmd, result.fail_reason,
-                  logfile, result.output)
-
-    # If logfile is 'None' (during attach), it breaks TailFile
-    # TODO: have a log file for attach too
-    if action is not constants.ES_ACTION_ATTACH:
-      lines = [utils.SafeEncode(val)
-               for val in utils.TailFile(logfile, lines=20)]
-    else:
-      lines = result.output[-20:]
-
-    _ThrowError("External storage's %s script failed (%s), last"
-                " lines of output:\n%s",
-                action, result.fail_reason, "\n".join(lines))
-
-  if action == constants.ES_ACTION_ATTACH:
-    return result.stdout
-
-
-def ExtStorageFromDisk(name, base_dir=None):
-  """Create an ExtStorage instance from disk.
-
-  This function will return an ExtStorage instance
-  if the given name is a valid ExtStorage name.
-
-  @type base_dir: string
-  @keyword base_dir: Base directory containing ExtStorage installations.
-                     Defaults to a search in all the ES_SEARCH_PATH dirs.
-  @rtype: tuple
-  @return: True and the ExtStorage instance if we find a valid one, or
-      False and the diagnose message on error
-
-  """
-  if base_dir is None:
-    es_base_dir = pathutils.ES_SEARCH_PATH
-  else:
-    es_base_dir = [base_dir]
-
-  es_dir = utils.FindFile(name, es_base_dir, os.path.isdir)
-
-  if es_dir is None:
-    return False, ("Directory for External Storage Provider %s not"
-                   " found in search path" % name)
-
-  # ES Files dictionary, we will populate it with the absolute path
-  # names; if the value is True, then it is a required file, otherwise
-  # an optional one
-  es_files = dict.fromkeys(constants.ES_SCRIPTS, True)
-
-  es_files[constants.ES_PARAMETERS_FILE] = True
-
-  for (filename, _) in es_files.items():
-    es_files[filename] = utils.PathJoin(es_dir, filename)
-
-    try:
-      st = os.stat(es_files[filename])
-    except EnvironmentError, err:
-      return False, ("File '%s' under path '%s' is missing (%s)" %
-                     (filename, es_dir, utils.ErrnoOrStr(err)))
-
-    if not stat.S_ISREG(stat.S_IFMT(st.st_mode)):
-      return False, ("File '%s' under path '%s' is not a regular file" %
-                     (filename, es_dir))
-
-    if filename in constants.ES_SCRIPTS:
-      if stat.S_IMODE(st.st_mode) & stat.S_IXUSR != stat.S_IXUSR:
-        return False, ("File '%s' under path '%s' is not executable" %
-                       (filename, es_dir))
-
-  parameters = []
-  if constants.ES_PARAMETERS_FILE in es_files:
-    parameters_file = es_files[constants.ES_PARAMETERS_FILE]
-    try:
-      parameters = utils.ReadFile(parameters_file).splitlines()
-    except EnvironmentError, err:
-      return False, ("Error while reading the EXT parameters file at %s: %s" %
-                     (parameters_file, utils.ErrnoOrStr(err)))
-    parameters = [v.split(None, 1) for v in parameters]
-
-  es_obj = \
-    objects.ExtStorage(name=name, path=es_dir,
-                       create_script=es_files[constants.ES_SCRIPT_CREATE],
-                       remove_script=es_files[constants.ES_SCRIPT_REMOVE],
-                       grow_script=es_files[constants.ES_SCRIPT_GROW],
-                       attach_script=es_files[constants.ES_SCRIPT_ATTACH],
-                       detach_script=es_files[constants.ES_SCRIPT_DETACH],
-                       setinfo_script=es_files[constants.ES_SCRIPT_SETINFO],
-                       verify_script=es_files[constants.ES_SCRIPT_VERIFY],
-                       supported_parameters=parameters)
-  return True, es_obj
-
-
-def _ExtStorageEnvironment(unique_id, ext_params,
-                           size=None, grow=None, metadata=None):
-  """Calculate the environment for an External Storage script.
-
-  @type unique_id: tuple (driver, vol_name)
-  @param unique_id: ExtStorage pool and name of the Volume
-  @type ext_params: dict
-  @param ext_params: the EXT parameters
-  @type size: string
-  @param size: size of the Volume (in mebibytes)
-  @type grow: string
-  @param grow: new size of Volume after grow (in mebibytes)
-  @type metadata: string
-  @param metadata: metadata info of the Volume
-  @rtype: dict
-  @return: dict of environment variables
-
-  """
-  vol_name = unique_id[1]
-
-  result = {}
-  result["VOL_NAME"] = vol_name
-
-  # EXT params
-  for pname, pvalue in ext_params.items():
-    result["EXTP_%s" % pname.upper()] = str(pvalue)
-
-  if size is not None:
-    result["VOL_SIZE"] = size
-
-  if grow is not None:
-    result["VOL_NEW_SIZE"] = grow
-
-  if metadata is not None:
-    result["VOL_METADATA"] = metadata
-
-  return result
-
-
-def _VolumeLogName(kind, es_name, volume):
-  """Compute the ExtStorage log filename for a given Volume and operation.
-
-  @type kind: string
-  @param kind: the operation type (e.g. create, remove etc.)
-  @type es_name: string
-  @param es_name: the ExtStorage name
-  @type volume: string
-  @param volume: the name of the Volume inside the External Storage
-
-  """
-  # Check if the extstorage log dir is a valid dir
-  if not os.path.isdir(pathutils.LOG_ES_DIR):
-    _ThrowError("Cannot find log directory: %s", pathutils.LOG_ES_DIR)
-
-  # TODO: Use tempfile.mkstemp to create unique filename
-  base = ("%s-%s-%s-%s.log" %
-          (kind, es_name, volume, utils.TimestampForFilename()))
-  return utils.PathJoin(pathutils.LOG_ES_DIR, base)
-
-
-DEV_MAP = {
-  constants.LD_LV: LogicalVolume,
-  constants.LD_DRBD8: DRBD8,
-  constants.LD_BLOCKDEV: PersistentBlockDevice,
-  constants.LD_RBD: RADOSBlockDevice,
-  constants.LD_EXT: ExtStorageDevice,
-  }
-
-if constants.ENABLE_FILE_STORAGE or constants.ENABLE_SHARED_FILE_STORAGE:
-  DEV_MAP[constants.LD_FILE] = FileStorage
-
-
-def _VerifyDiskType(dev_type):
-  if dev_type not in DEV_MAP:
-    raise errors.ProgrammerError("Invalid block device type '%s'" % dev_type)
-
-
-def _VerifyDiskParams(disk):
-  """Verifies if all disk parameters are set.
-
-  """
-  missing = set(constants.DISK_LD_DEFAULTS[disk.dev_type]) - set(disk.params)
-  if missing:
-    raise errors.ProgrammerError("Block device is missing disk parameters: %s" %
-                                 missing)
-
-
-def FindDevice(disk, children):
-  """Search for an existing, assembled device.
-
-  This will succeed only if the device exists and is assembled, but it
-  does not do any actions in order to activate the device.
-
-  @type disk: L{objects.Disk}
-  @param disk: the disk object to find
-  @type children: list of L{bdev.BlockDev}
-  @param children: the list of block devices that are children of the device
-                  represented by the disk parameter
-
-  """
-  _VerifyDiskType(disk.dev_type)
-  device = DEV_MAP[disk.dev_type](disk.physical_id, children, disk.size,
-                                  disk.params)
-  if not device.attached:
-    return None
-  return device
-
-
-def Assemble(disk, children):
-  """Try to attach or assemble an existing device.
-
-  This will attach to assemble the device, as needed, to bring it
-  fully up. It must be safe to run on already-assembled devices.
-
-  @type disk: L{objects.Disk}
-  @param disk: the disk object to assemble
-  @type children: list of L{bdev.BlockDev}
-  @param children: the list of block devices that are children of the device
-                  represented by the disk parameter
-
-  """
-  _VerifyDiskType(disk.dev_type)
-  _VerifyDiskParams(disk)
-  device = DEV_MAP[disk.dev_type](disk.physical_id, children, disk.size,
-                                  disk.params)
-  device.Assemble()
-  return device
-
-
-def Create(disk, children, excl_stor):
-  """Create a device.
-
-  @type disk: L{objects.Disk}
-  @param disk: the disk object to create
-  @type children: list of L{bdev.BlockDev}
-  @param children: the list of block devices that are children of the device
-                  represented by the disk parameter
-  @type excl_stor: boolean
-  @param excl_stor: Whether exclusive_storage is active
-
-  """
-  _VerifyDiskType(disk.dev_type)
-  _VerifyDiskParams(disk)
-  device = DEV_MAP[disk.dev_type].Create(disk.physical_id, children, disk.size,
-                                         disk.params, excl_stor)
-  return device
diff --git a/lib/block/__init__.py b/lib/block/__init__.py
new file mode 100644
index 0000000..9b9e38c
--- /dev/null
+++ b/lib/block/__init__.py
@@ -0,0 +1,24 @@
+#
+#
+
+# Copyright (C) 2006, 2007, 2008 Google Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.
+
+
+"""Block device abstraction
+
+"""
diff --git a/lib/block/bdev.py b/lib/block/bdev.py
new file mode 100644
index 0000000..649d92e
--- /dev/null
+++ b/lib/block/bdev.py
@@ -0,0 +1,3442 @@
+#
+#
+
+# Copyright (C) 2006, 2007, 2010, 2011, 2012, 2013 Google Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.
+
+
+"""Block device abstraction"""
+
+import re
+import time
+import errno
+import shlex
+import stat
+import pyparsing as pyp
+import os
+import logging
+import math
+
+from ganeti import utils
+from ganeti import errors
+from ganeti import constants
+from ganeti import objects
+from ganeti import compat
+from ganeti import netutils
+from ganeti import pathutils
+from ganeti import serializer
+
+
+# Size of reads in _CanReadDevice
+_DEVICE_READ_SIZE = 128 * 1024
+
+
+class RbdShowmappedJsonError(Exception):
+  """`rbd showmmapped' JSON formatting error Exception class.
+
+  """
+  pass
+
+
+def _IgnoreError(fn, *args, **kwargs):
+  """Executes the given function, ignoring BlockDeviceErrors.
+
+  This is used in order to simplify the execution of cleanup or
+  rollback functions.
+
+  @rtype: boolean
+  @return: True when fn didn't raise an exception, False otherwise
+
+  """
+  try:
+    fn(*args, **kwargs)
+    return True
+  except errors.BlockDeviceError, err:
+    logging.warning("Caught BlockDeviceError but ignoring: %s", str(err))
+    return False
+
+
+def _ThrowError(msg, *args):
+  """Log an error to the node daemon and the raise an exception.
+
+  @type msg: string
+  @param msg: the text of the exception
+  @raise errors.BlockDeviceError
+
+  """
+  if args:
+    msg = msg % args
+  logging.error(msg)
+  raise errors.BlockDeviceError(msg)
+
+
+def _CheckResult(result):
+  """Throws an error if the given result is a failed one.
+
+  @param result: result from RunCmd
+
+  """
+  if result.failed:
+    _ThrowError("Command: %s error: %s - %s", result.cmd, result.fail_reason,
+                result.output)
+
+
+def _CanReadDevice(path):
+  """Check if we can read from the given device.
+
+  This tries to read the first 128k of the device.
+
+  """
+  try:
+    utils.ReadFile(path, size=_DEVICE_READ_SIZE)
+    return True
+  except EnvironmentError:
+    logging.warning("Can't read from device %s", path, exc_info=True)
+    return False
+
+
+def _GetForbiddenFileStoragePaths():
+  """Builds a list of path prefixes which shouldn't be used for file storage.
+
+  @rtype: frozenset
+
+  """
+  paths = set([
+    "/boot",
+    "/dev",
+    "/etc",
+    "/home",
+    "/proc",
+    "/root",
+    "/sys",
+    ])
+
+  for prefix in ["", "/usr", "/usr/local"]:
+    paths.update(map(lambda s: "%s/%s" % (prefix, s),
+                     ["bin", "lib", "lib32", "lib64", "sbin"]))
+
+  return compat.UniqueFrozenset(map(os.path.normpath, paths))
+
+
+def _ComputeWrongFileStoragePaths(paths,
+                                  _forbidden=_GetForbiddenFileStoragePaths()):
+  """Cross-checks a list of paths for prefixes considered bad.
+
+  Some paths, e.g. "/bin", should not be used for file storage.
+
+  @type paths: list
+  @param paths: List of paths to be checked
+  @rtype: list
+  @return: Sorted list of paths for which the user should be warned
+
+  """
+  def _Check(path):
+    return (not os.path.isabs(path) or
+            path in _forbidden or
+            filter(lambda p: utils.IsBelowDir(p, path), _forbidden))
+
+  return utils.NiceSort(filter(_Check, map(os.path.normpath, paths)))
+
+
+def ComputeWrongFileStoragePaths(_filename=pathutils.FILE_STORAGE_PATHS_FILE):
+  """Returns a list of file storage paths whose prefix is considered bad.
+
+  See L{_ComputeWrongFileStoragePaths}.
+
+  """
+  return _ComputeWrongFileStoragePaths(_LoadAllowedFileStoragePaths(_filename))
+
+
+def _CheckFileStoragePath(path, allowed):
+  """Checks if a path is in a list of allowed paths for file storage.
+
+  @type path: string
+  @param path: Path to check
+  @type allowed: list
+  @param allowed: List of allowed paths
+  @raise errors.FileStoragePathError: If the path is not allowed
+
+  """
+  if not os.path.isabs(path):
+    raise errors.FileStoragePathError("File storage path must be absolute,"
+                                      " got '%s'" % path)
+
+  for i in allowed:
+    if not os.path.isabs(i):
+      logging.info("Ignoring relative path '%s' for file storage", i)
+      continue
+
+    if utils.IsBelowDir(i, path):
+      break
+  else:
+    raise errors.FileStoragePathError("Path '%s' is not acceptable for file"
+                                      " storage" % path)
+
+
+def _LoadAllowedFileStoragePaths(filename):
+  """Loads file containing allowed file storage paths.
+
+  @rtype: list
+  @return: List of allowed paths (can be an empty list)
+
+  """
+  try:
+    contents = utils.ReadFile(filename)
+  except EnvironmentError:
+    return []
+  else:
+    return utils.FilterEmptyLinesAndComments(contents)
+
+
+def CheckFileStoragePath(path, _filename=pathutils.FILE_STORAGE_PATHS_FILE):
+  """Checks if a path is allowed for file storage.
+
+  @type path: string
+  @param path: Path to check
+  @raise errors.FileStoragePathError: If the path is not allowed
+
+  """
+  allowed = _LoadAllowedFileStoragePaths(_filename)
+
+  if _ComputeWrongFileStoragePaths([path]):
+    raise errors.FileStoragePathError("Path '%s' uses a forbidden prefix" %
+                                      path)
+
+  _CheckFileStoragePath(path, allowed)
+
+
+class BlockDev(object):
+  """Block device abstract class.
+
+  A block device can be in the following states:
+    - not existing on the system, and by `Create()` it goes into:
+    - existing but not setup/not active, and by `Assemble()` goes into:
+    - active read-write and by `Open()` it goes into
+    - online (=used, or ready for use)
+
+  A device can also be online but read-only, however we are not using
+  the readonly state (LV has it, if needed in the future) and we are
+  usually looking at this like at a stack, so it's easier to
+  conceptualise the transition from not-existing to online and back
+  like a linear one.
+
+  The many different states of the device are due to the fact that we
+  need to cover many device types:
+    - logical volumes are created, lvchange -a y $lv, and used
+    - drbd devices are attached to a local disk/remote peer and made primary
+
+  A block device is identified by three items:
+    - the /dev path of the device (dynamic)
+    - a unique ID of the device (static)
+    - it's major/minor pair (dynamic)
+
+  Not all devices implement both the first two as distinct items. LVM
+  logical volumes have their unique ID (the pair volume group, logical
+  volume name) in a 1-to-1 relation to the dev path. For DRBD devices,
+  the /dev path is again dynamic and the unique id is the pair (host1,
+  dev1), (host2, dev2).
+
+  You can get to a device in two ways:
+    - creating the (real) device, which returns you
+      an attached instance (lvcreate)
+    - attaching of a python instance to an existing (real) device
+
+  The second point, the attachment to a device, is different
+  depending on whether the device is assembled or not. At init() time,
+  we search for a device with the same unique_id as us. If found,
+  good. It also means that the device is already assembled. If not,
+  after assembly we'll have our correct major/minor.
+
+  """
+  def __init__(self, unique_id, children, size, params):
+    self._children = children
+    self.dev_path = None
+    self.unique_id = unique_id
+    self.major = None
+    self.minor = None
+    self.attached = False
+    self.size = size
+    self.params = params
+
+  def Assemble(self):
+    """Assemble the device from its components.
+
+    Implementations of this method by child classes must ensure that:
+      - after the device has been assembled, it knows its major/minor
+        numbers; this allows other devices (usually parents) to probe
+        correctly for their children
+      - calling this method on an existing, in-use device is safe
+      - if the device is already configured (and in an OK state),
+        this method is idempotent
+
+    """
+    pass
+
+  def Attach(self):
+    """Find a device which matches our config and attach to it.
+
+    """
+    raise NotImplementedError
+
+  def Close(self):
+    """Notifies that the device will no longer be used for I/O.
+
+    """
+    raise NotImplementedError
+
+  @classmethod
+  def Create(cls, unique_id, children, size, params, excl_stor):
+    """Create the device.
+
+    If the device cannot be created, it will return None
+    instead. Error messages go to the logging system.
+
+    Note that for some devices, the unique_id is used, and for other,
+    the children. The idea is that these two, taken together, are
+    enough for both creation and assembly (later).
+
+    """
+    raise NotImplementedError
+
+  def Remove(self):
+    """Remove this device.
+
+    This makes sense only for some of the device types: LV and file
+    storage. Also note that if the device can't attach, the removal
+    can't be completed.
+
+    """
+    raise NotImplementedError
+
+  def Rename(self, new_id):
+    """Rename this device.
+
+    This may or may not make sense for a given device type.
+
+    """
+    raise NotImplementedError
+
+  def Open(self, force=False):
+    """Make the device ready for use.
+
+    This makes the device ready for I/O. For now, just the DRBD
+    devices need this.
+
+    The force parameter signifies that if the device has any kind of
+    --force thing, it should be used, we know what we are doing.
+
+    """
+    raise NotImplementedError
+
+  def Shutdown(self):
+    """Shut down the device, freeing its children.
+
+    This undoes the `Assemble()` work, except for the child
+    assembling; as such, the children on the device are still
+    assembled after this call.
+
+    """
+    raise NotImplementedError
+
+  def SetSyncParams(self, params):
+    """Adjust the synchronization parameters of the mirror.
+
+    In case this is not a mirroring device, this is no-op.
+
+    @param params: dictionary of LD level disk parameters related to the
+    synchronization.
+    @rtype: list
+    @return: a list of error messages, emitted both by the current node and by
+    children. An empty list means no errors.
+
+    """
+    result = []
+    if self._children:
+      for child in self._children:
+        result.extend(child.SetSyncParams(params))
+    return result
+
+  def PauseResumeSync(self, pause):
+    """Pause/Resume the sync of the mirror.
+
+    In case this is not a mirroring device, this is no-op.
+
+    @param pause: Whether to pause or resume
+
+    """
+    result = True
+    if self._children:
+      for child in self._children:
+        result = result and child.PauseResumeSync(pause)
+    return result
+
+  def GetSyncStatus(self):
+    """Returns the sync status of the device.
+
+    If this device is a mirroring device, this function returns the
+    status of the mirror.
+
+    If sync_percent is None, it means the device is not syncing.
+
+    If estimated_time is None, it means we can't estimate
+    the time needed, otherwise it's the time left in seconds.
+
+    If is_degraded is True, it means the device is missing
+    redundancy. This is usually a sign that something went wrong in
+    the device setup, if sync_percent is None.
+
+    The ldisk parameter represents the degradation of the local
+    data. This is only valid for some devices, the rest will always
+    return False (not degraded).
+
+    @rtype: objects.BlockDevStatus
+
+    """
+    return objects.BlockDevStatus(dev_path=self.dev_path,
+                                  major=self.major,
+                                  minor=self.minor,
+                                  sync_percent=None,
+                                  estimated_time=None,
+                                  is_degraded=False,
+                                  ldisk_status=constants.LDS_OKAY)
+
+  def CombinedSyncStatus(self):
+    """Calculate the mirror status recursively for our children.
+
+    The return value is the same as for `GetSyncStatus()` except the
+    minimum percent and maximum time are calculated across our
+    children.
+
+    @rtype: objects.BlockDevStatus
+
+    """
+    status = self.GetSyncStatus()
+
+    min_percent = status.sync_percent
+    max_time = status.estimated_time
+    is_degraded = status.is_degraded
+    ldisk_status = status.ldisk_status
+
+    if self._children:
+      for child in self._children:
+        child_status = child.GetSyncStatus()
+
+        if min_percent is None:
+          min_percent = child_status.sync_percent
+        elif child_status.sync_percent is not None:
+          min_percent = min(min_percent, child_status.sync_percent)
+
+        if max_time is None:
+          max_time = child_status.estimated_time
+        elif child_status.estimated_time is not None:
+          max_time = max(max_time, child_status.estimated_time)
+
+        is_degraded = is_degraded or child_status.is_degraded
+
+        if ldisk_status is None:
+          ldisk_status = child_status.ldisk_status
+        elif child_status.ldisk_status is not None:
+          ldisk_status = max(ldisk_status, child_status.ldisk_status)
+
+    return objects.BlockDevStatus(dev_path=self.dev_path,
+                                  major=self.major,
+                                  minor=self.minor,
+                                  sync_percent=min_percent,
+                                  estimated_time=max_time,
+                                  is_degraded=is_degraded,
+                                  ldisk_status=ldisk_status)
+
+  def SetInfo(self, text):
+    """Update metadata with info text.
+
+    Only supported for some device types.
+
+    """
+    for child in self._children:
+      child.SetInfo(text)
+
+  def Grow(self, amount, dryrun, backingstore):
+    """Grow the block device.
+
+    @type amount: integer
+    @param amount: the amount (in mebibytes) to grow with
+    @type dryrun: boolean
+    @param dryrun: whether to execute the operation in simulation mode
+        only, without actually increasing the size
+    @param backingstore: whether to execute the operation on backing storage
+        only, or on "logical" storage only; e.g. DRBD is logical storage,
+        whereas LVM, file, RBD are backing storage
+
+    """
+    raise NotImplementedError
+
+  def GetActualSize(self):
+    """Return the actual disk size.
+
+    @note: the device needs to be active when this is called
+
+    """
+    assert self.attached, "BlockDevice not attached in GetActualSize()"
+    result = utils.RunCmd(["blockdev", "--getsize64", self.dev_path])
+    if result.failed:
+      _ThrowError("blockdev failed (%s): %s",
+                  result.fail_reason, result.output)
+    try:
+      sz = int(result.output.strip())
+    except (ValueError, TypeError), err:
+      _ThrowError("Failed to parse blockdev output: %s", str(err))
+    return sz
+
+  def __repr__(self):
+    return ("<%s: unique_id: %s, children: %s, %s:%s, %s>" %
+            (self.__class__, self.unique_id, self._children,
+             self.major, self.minor, self.dev_path))
+
+
+class LogicalVolume(BlockDev):
+  """Logical Volume block device.
+
+  """
+  _VALID_NAME_RE = re.compile("^[a-zA-Z0-9+_.-]*$")
+  _INVALID_NAMES = compat.UniqueFrozenset([".", "..", "snapshot", "pvmove"])
+  _INVALID_SUBSTRINGS = compat.UniqueFrozenset(["_mlog", "_mimage"])
+
+  def __init__(self, unique_id, children, size, params):
+    """Attaches to a LV device.
+
+    The unique_id is a tuple (vg_name, lv_name)
+
+    """
+    super(LogicalVolume, self).__init__(unique_id, children, size, params)
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise ValueError("Invalid configuration data %s" % str(unique_id))
+    self._vg_name, self._lv_name = unique_id
+    self._ValidateName(self._vg_name)
+    self._ValidateName(self._lv_name)
+    self.dev_path = utils.PathJoin("/dev", self._vg_name, self._lv_name)
+    self._degraded = True
+    self.major = self.minor = self.pe_size = self.stripe_count = None
+    self.Attach()
+
+  @staticmethod
+  def _GetStdPvSize(pvs_info):
+    """Return the the standard PV size (used with exclusive storage).
+
+    @param pvs_info: list of objects.LvmPvInfo, cannot be empty
+    @rtype: float
+    @return: size in MiB
+
+    """
+    assert len(pvs_info) > 0
+    smallest = min([pv.size for pv in pvs_info])
+    return smallest / (1 + constants.PART_MARGIN + constants.PART_RESERVED)
+
+  @staticmethod
+  def _ComputeNumPvs(size, pvs_info):
+    """Compute the number of PVs needed for an LV (with exclusive storage).
+
+    @type size: float
+    @param size: LV size in MiB
+    @param pvs_info: list of objects.LvmPvInfo, cannot be empty
+    @rtype: integer
+    @return: number of PVs needed
+    """
+    assert len(pvs_info) > 0
+    pv_size = float(LogicalVolume._GetStdPvSize(pvs_info))
+    return int(math.ceil(float(size) / pv_size))
+
+  @staticmethod
+  def _GetEmptyPvNames(pvs_info, max_pvs=None):
+    """Return a list of empty PVs, by name.
+
+    """
+    empty_pvs = filter(objects.LvmPvInfo.IsEmpty, pvs_info)
+    if max_pvs is not None:
+      empty_pvs = empty_pvs[:max_pvs]
+    return map((lambda pv: pv.name), empty_pvs)
+
+  @classmethod
+  def Create(cls, unique_id, children, size, params, excl_stor):
+    """Create a new logical volume.
+
+    """
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise errors.ProgrammerError("Invalid configuration data %s" %
+                                   str(unique_id))
+    vg_name, lv_name = unique_id
+    cls._ValidateName(vg_name)
+    cls._ValidateName(lv_name)
+    pvs_info = cls.GetPVInfo([vg_name])
+    if not pvs_info:
+      if excl_stor:
+        msg = "No (empty) PVs found"
+      else:
+        msg = "Can't compute PV info for vg %s" % vg_name
+      _ThrowError(msg)
+    pvs_info.sort(key=(lambda pv: pv.free), reverse=True)
+
+    pvlist = [pv.name for pv in pvs_info]
+    if compat.any(":" in v for v in pvlist):
+      _ThrowError("Some of your PVs have the invalid character ':' in their"
+                  " name, this is not supported - please filter them out"
+                  " in lvm.conf using either 'filter' or 'preferred_names'")
+
+    current_pvs = len(pvlist)
+    desired_stripes = params[constants.LDP_STRIPES]
+    stripes = min(current_pvs, desired_stripes)
+
+    if excl_stor:
+      (err_msgs, _) = utils.LvmExclusiveCheckNodePvs(pvs_info)
+      if err_msgs:
+        for m in err_msgs:
+          logging.warning(m)
+      req_pvs = cls._ComputeNumPvs(size, pvs_info)
+      pvlist = cls._GetEmptyPvNames(pvs_info, req_pvs)
+      current_pvs = len(pvlist)
+      if current_pvs < req_pvs:
+        _ThrowError("Not enough empty PVs to create a disk of %d MB:"
+                    " %d available, %d needed", size, current_pvs, req_pvs)
+      assert current_pvs == len(pvlist)
+      if stripes > current_pvs:
+        # No warning issued for this, as it's no surprise
+        stripes = current_pvs
+
+    else:
+      if stripes < desired_stripes:
+        logging.warning("Could not use %d stripes for VG %s, as only %d PVs are"
+                        " available.", desired_stripes, vg_name, current_pvs)
+      free_size = sum([pv.free for pv in pvs_info])
+      # The size constraint should have been checked from the master before
+      # calling the create function.
+      if free_size < size:
+        _ThrowError("Not enough free space: required %s,"
+                    " available %s", size, free_size)
+
+    # If the free space is not well distributed, we won't be able to
+    # create an optimally-striped volume; in that case, we want to try
+    # with N, N-1, ..., 2, and finally 1 (non-stripped) number of
+    # stripes
+    cmd = ["lvcreate", "-L%dm" % size, "-n%s" % lv_name]
+    for stripes_arg in range(stripes, 0, -1):
+      result = utils.RunCmd(cmd + ["-i%d" % stripes_arg] + [vg_name] + pvlist)
+      if not result.failed:
+        break
+    if result.failed:
+      _ThrowError("LV create failed (%s): %s",
+                  result.fail_reason, result.output)
+    return LogicalVolume(unique_id, children, size, params)
+
+  @staticmethod
+  def _GetVolumeInfo(lvm_cmd, fields):
+    """Returns LVM Volume infos using lvm_cmd
+
+    @param lvm_cmd: Should be one of "pvs", "vgs" or "lvs"
+    @param fields: Fields to return
+    @return: A list of dicts each with the parsed fields
+
+    """
+    if not fields:
+      raise errors.ProgrammerError("No fields specified")
+
+    sep = "|"
+    cmd = [lvm_cmd, "--noheadings", "--nosuffix", "--units=m", "--unbuffered",
+           "--separator=%s" % sep, "-o%s" % ",".join(fields)]
+
+    result = utils.RunCmd(cmd)
+    if result.failed:
+      raise errors.CommandError("Can't get the volume information: %s - %s" %
+                                (result.fail_reason, result.output))
+
+    data = []
+    for line in result.stdout.splitlines():
+      splitted_fields = line.strip().split(sep)
+
+      if len(fields) != len(splitted_fields):
+        raise errors.CommandError("Can't parse %s output: line '%s'" %
+                                  (lvm_cmd, line))
+
+      data.append(splitted_fields)
+
+    return data
+
+  @classmethod
+  def GetPVInfo(cls, vg_names, filter_allocatable=True, include_lvs=False):
+    """Get the free space info for PVs in a volume group.
+
+    @param vg_names: list of volume group names, if empty all will be returned
+    @param filter_allocatable: whether to skip over unallocatable PVs
+    @param include_lvs: whether to include a list of LVs hosted on each PV
+
+    @rtype: list
+    @return: list of objects.LvmPvInfo objects
+
+    """
+    # We request "lv_name" field only if we care about LVs, so we don't get
+    # a long list of entries with many duplicates unless we really have to.
+    # The duplicate "pv_name" field will be ignored.
+    if include_lvs:
+      lvfield = "lv_name"
+    else:
+      lvfield = "pv_name"
+    try:
+      info = cls._GetVolumeInfo("pvs", ["pv_name", "vg_name", "pv_free",
+                                        "pv_attr", "pv_size", lvfield])
+    except errors.GenericError, err:
+      logging.error("Can't get PV information: %s", err)
+      return None
+
+    # When asked for LVs, "pvs" may return multiple entries for the same PV-LV
+    # pair. We sort entries by PV name and then LV name, so it's easy to weed
+    # out duplicates.
+    if include_lvs:
+      info.sort(key=(lambda i: (i[0], i[5])))
+    data = []
+    lastpvi = None
+    for (pv_name, vg_name, pv_free, pv_attr, pv_size, lv_name) in info:
+      # (possibly) skip over pvs which are not allocatable
+      if filter_allocatable and pv_attr[0] != "a":
+        continue
+      # (possibly) skip over pvs which are not in the right volume group(s)
+      if vg_names and vg_name not in vg_names:
+        continue
+      # Beware of duplicates (check before inserting)
+      if lastpvi and lastpvi.name == pv_name:
+        if include_lvs and lv_name:
+          if not lastpvi.lv_list or lastpvi.lv_list[-1] != lv_name:
+            lastpvi.lv_list.append(lv_name)
+      else:
+        if include_lvs and lv_name:
+          lvl = [lv_name]
+        else:
+          lvl = []
+        lastpvi = objects.LvmPvInfo(name=pv_name, vg_name=vg_name,
+                                    size=float(pv_size), free=float(pv_free),
+                                    attributes=pv_attr, lv_list=lvl)
+        data.append(lastpvi)
+
+    return data
+
+  @classmethod
+  def _GetExclusiveStorageVgFree(cls, vg_name):
+    """Return the free disk space in the given VG, in exclusive storage mode.
+
+    @type vg_name: string
+    @param vg_name: VG name
+    @rtype: float
+    @return: free space in MiB
+    """
+    pvs_info = cls.GetPVInfo([vg_name])
+    if not pvs_info:
+      return 0.0
+    pv_size = cls._GetStdPvSize(pvs_info)
+    num_pvs = len(cls._GetEmptyPvNames(pvs_info))
+    return pv_size * num_pvs
+
+  @classmethod
+  def GetVGInfo(cls, vg_names, excl_stor, filter_readonly=True):
+    """Get the free space info for specific VGs.
+
+    @param vg_names: list of volume group names, if empty all will be returned
+    @param excl_stor: whether exclusive_storage is enabled
+    @param filter_readonly: whether to skip over readonly VGs
+
+    @rtype: list
+    @return: list of tuples (free_space, total_size, name) with free_space in
+             MiB
+
+    """
+    try:
+      info = cls._GetVolumeInfo("vgs", ["vg_name", "vg_free", "vg_attr",
+                                        "vg_size"])
+    except errors.GenericError, err:
+      logging.error("Can't get VG information: %s", err)
+      return None
+
+    data = []
+    for vg_name, vg_free, vg_attr, vg_size in info:
+      # (possibly) skip over vgs which are not writable
+      if filter_readonly and vg_attr[0] == "r":
+        continue
+      # (possibly) skip over vgs which are not in the right volume group(s)
+      if vg_names and vg_name not in vg_names:
+        continue
+      # Exclusive storage needs a different concept of free space
+      if excl_stor:
+        es_free = cls._GetExclusiveStorageVgFree(vg_name)
+        assert es_free <= vg_free
+        vg_free = es_free
+      data.append((float(vg_free), float(vg_size), vg_name))
+
+    return data
+
+  @classmethod
+  def _ValidateName(cls, name):
+    """Validates that a given name is valid as VG or LV name.
+
+    The list of valid characters and restricted names is taken out of
+    the lvm(8) manpage, with the simplification that we enforce both
+    VG and LV restrictions on the names.
+
+    """
+    if (not cls._VALID_NAME_RE.match(name) or
+        name in cls._INVALID_NAMES or
+        compat.any(substring in name for substring in cls._INVALID_SUBSTRINGS)):
+      _ThrowError("Invalid LVM name '%s'", name)
+
+  def Remove(self):
+    """Remove this logical volume.
+
+    """
+    if not self.minor and not self.Attach():
+      # the LV does not exist
+      return
+    result = utils.RunCmd(["lvremove", "-f", "%s/%s" %
+                           (self._vg_name, self._lv_name)])
+    if result.failed:
+      _ThrowError("Can't lvremove: %s - %s", result.fail_reason, result.output)
+
+  def Rename(self, new_id):
+    """Rename this logical volume.
+
+    """
+    if not isinstance(new_id, (tuple, list)) or len(new_id) != 2:
+      raise errors.ProgrammerError("Invalid new logical id '%s'" % new_id)
+    new_vg, new_name = new_id
+    if new_vg != self._vg_name:
+      raise errors.ProgrammerError("Can't move a logical volume across"
+                                   " volume groups (from %s to to %s)" %
+                                   (self._vg_name, new_vg))
+    result = utils.RunCmd(["lvrename", new_vg, self._lv_name, new_name])
+    if result.failed:
+      _ThrowError("Failed to rename the logical volume: %s", result.output)
+    self._lv_name = new_name
+    self.dev_path = utils.PathJoin("/dev", self._vg_name, self._lv_name)
+
+  def Attach(self):
+    """Attach to an existing LV.
+
+    This method will try to see if an existing and active LV exists
+    which matches our name. If so, its major/minor will be
+    recorded.
+
+    """
+    self.attached = False
+    result = utils.RunCmd(["lvs", "--noheadings", "--separator=,",
+                           "--units=m", "--nosuffix",
+                           "-olv_attr,lv_kernel_major,lv_kernel_minor,"
+                           "vg_extent_size,stripes", self.dev_path])
+    if result.failed:
+      logging.error("Can't find LV %s: %s, %s",
+                    self.dev_path, result.fail_reason, result.output)
+      return False
+    # the output can (and will) have multiple lines for multi-segment
+    # LVs, as the 'stripes' parameter is a segment one, so we take
+    # only the last entry, which is the one we're interested in; note
+    # that with LVM2 anyway the 'stripes' value must be constant
+    # across segments, so this is a no-op actually
+    out = result.stdout.splitlines()
+    if not out: # totally empty result? splitlines() returns at least
+                # one line for any non-empty string
+      logging.error("Can't parse LVS output, no lines? Got '%s'", str(out))
+      return False
+    out = out[-1].strip().rstrip(",")
+    out = out.split(",")
+    if len(out) != 5:
+      logging.error("Can't parse LVS output, len(%s) != 5", str(out))
+      return False
+
+    status, major, minor, pe_size, stripes = out
+    if len(status) < 6:
+      logging.error("lvs lv_attr is not at least 6 characters (%s)", status)
+      return False
+
+    try:
+      major = int(major)
+      minor = int(minor)
+    except (TypeError, ValueError), err:
+      logging.error("lvs major/minor cannot be parsed: %s", str(err))
+
+    try:
+      pe_size = int(float(pe_size))
+    except (TypeError, ValueError), err:
+      logging.error("Can't parse vg extent size: %s", err)
+      return False
+
+    try:
+      stripes = int(stripes)
+    except (TypeError, ValueError), err:
+      logging.error("Can't parse the number of stripes: %s", err)
+      return False
+
+    self.major = major
+    self.minor = minor
+    self.pe_size = pe_size
+    self.stripe_count = stripes
+    self._degraded = status[0] == "v" # virtual volume, i.e. doesn't backing
+                                      # storage
+    self.attached = True
+    return True
+
+  def Assemble(self):
+    """Assemble the device.
+
+    We always run `lvchange -ay` on the LV to ensure it's active before
+    use, as there were cases when xenvg was not active after boot
+    (also possibly after disk issues).
+
+    """
+    result = utils.RunCmd(["lvchange", "-ay", self.dev_path])
+    if result.failed:
+      _ThrowError("Can't activate lv %s: %s", self.dev_path, result.output)
+
+  def Shutdown(self):
+    """Shutdown the device.
+
+    This is a no-op for the LV device type, as we don't deactivate the
+    volumes on shutdown.
+
+    """
+    pass
+
+  def GetSyncStatus(self):
+    """Returns the sync status of the device.
+
+    If this device is a mirroring device, this function returns the
+    status of the mirror.
+
+    For logical volumes, sync_percent and estimated_time are always
+    None (no recovery in progress, as we don't handle the mirrored LV
+    case). The is_degraded parameter is the inverse of the ldisk
+    parameter.
+
+    For the ldisk parameter, we check if the logical volume has the
+    'virtual' type, which means it's not backed by existing storage
+    anymore (read from it return I/O error). This happens after a
+    physical disk failure and subsequent 'vgreduce --removemissing' on
+    the volume group.
+
+    The status was already read in Attach, so we just return it.
+
+    @rtype: objects.BlockDevStatus
+
+    """
+    if self._degraded:
+      ldisk_status = constants.LDS_FAULTY
+    else:
+      ldisk_status = constants.LDS_OKAY
+
+    return objects.BlockDevStatus(dev_path=self.dev_path,
+                                  major=self.major,
+                                  minor=self.minor,
+                                  sync_percent=None,
+                                  estimated_time=None,
+                                  is_degraded=self._degraded,
+                                  ldisk_status=ldisk_status)
+
+  def Open(self, force=False):
+    """Make the device ready for I/O.
+
+    This is a no-op for the LV device type.
+
+    """
+    pass
+
+  def Close(self):
+    """Notifies that the device will no longer be used for I/O.
+
+    This is a no-op for the LV device type.
+
+    """
+    pass
+
+  def Snapshot(self, size):
+    """Create a snapshot copy of an lvm block device.
+
+    @returns: tuple (vg, lv)
+
+    """
+    snap_name = self._lv_name + ".snap"
+
+    # remove existing snapshot if found
+    snap = LogicalVolume((self._vg_name, snap_name), None, size, self.params)
+    _IgnoreError(snap.Remove)
+
+    vg_info = self.GetVGInfo([self._vg_name], False)
+    if not vg_info:
+      _ThrowError("Can't compute VG info for vg %s", self._vg_name)
+    free_size, _, _ = vg_info[0]
+    if free_size < size:
+      _ThrowError("Not enough free space: required %s,"
+                  " available %s", size, free_size)
+
+    _CheckResult(utils.RunCmd(["lvcreate", "-L%dm" % size, "-s",
+                               "-n%s" % snap_name, self.dev_path]))
+
+    return (self._vg_name, snap_name)
+
+  def _RemoveOldInfo(self):
+    """Try to remove old tags from the lv.
+
+    """
+    result = utils.RunCmd(["lvs", "-o", "tags", "--noheadings", "--nosuffix",
+                           self.dev_path])
+    _CheckResult(result)
+
+    raw_tags = result.stdout.strip()
+    if raw_tags:
+      for tag in raw_tags.split(","):
+        _CheckResult(utils.RunCmd(["lvchange", "--deltag",
+                                   tag.strip(), self.dev_path]))
+
+  def SetInfo(self, text):
+    """Update metadata with info text.
+
+    """
+    BlockDev.SetInfo(self, text)
+
+    self._RemoveOldInfo()
+
+    # Replace invalid characters
+    text = re.sub("^[^A-Za-z0-9_+.]", "_", text)
+    text = re.sub("[^-A-Za-z0-9_+.]", "_", text)
+
+    # Only up to 128 characters are allowed
+    text = text[:128]
+
+    _CheckResult(utils.RunCmd(["lvchange", "--addtag", text, self.dev_path]))
+
+  def Grow(self, amount, dryrun, backingstore):
+    """Grow the logical volume.
+
+    """
+    if not backingstore:
+      return
+    if self.pe_size is None or self.stripe_count is None:
+      if not self.Attach():
+        _ThrowError("Can't attach to LV during Grow()")
+    full_stripe_size = self.pe_size * self.stripe_count
+    rest = amount % full_stripe_size
+    if rest != 0:
+      amount += full_stripe_size - rest
+    cmd = ["lvextend", "-L", "+%dm" % amount]
+    if dryrun:
+      cmd.append("--test")
+    # we try multiple algorithms since the 'best' ones might not have
+    # space available in the right place, but later ones might (since
+    # they have less constraints); also note that only recent LVM
+    # supports 'cling'
+    for alloc_policy in "contiguous", "cling", "normal":
+      result = utils.RunCmd(cmd + ["--alloc", alloc_policy, self.dev_path])
+      if not result.failed:
+        return
+    _ThrowError("Can't grow LV %s: %s", self.dev_path, result.output)
+
+
+class DRBD8Status(object):
+  """A DRBD status representation class.
+
+  Note that this doesn't support unconfigured devices (cs:Unconfigured).
+
+  """
+  UNCONF_RE = re.compile(r"\s*[0-9]+:\s*cs:Unconfigured$")
+  LINE_RE = re.compile(r"\s*[0-9]+:\s*cs:(\S+)\s+(?:st|ro):([^/]+)/(\S+)"
+                       "\s+ds:([^/]+)/(\S+)\s+.*$")
+  SYNC_RE = re.compile(r"^.*\ssync'ed:\s*([0-9.]+)%.*"
+                       # Due to a bug in drbd in the kernel, introduced in
+                       # commit 4b0715f096 (still unfixed as of 2011-08-22)
+                       "(?:\s|M)"
+                       "finish: ([0-9]+):([0-9]+):([0-9]+)\s.*$")
+
+  CS_UNCONFIGURED = "Unconfigured"
+  CS_STANDALONE = "StandAlone"
+  CS_WFCONNECTION = "WFConnection"
+  CS_WFREPORTPARAMS = "WFReportParams"
+  CS_CONNECTED = "Connected"
+  CS_STARTINGSYNCS = "StartingSyncS"
+  CS_STARTINGSYNCT = "StartingSyncT"
+  CS_WFBITMAPS = "WFBitMapS"
+  CS_WFBITMAPT = "WFBitMapT"
+  CS_WFSYNCUUID = "WFSyncUUID"
+  CS_SYNCSOURCE = "SyncSource"
+  CS_SYNCTARGET = "SyncTarget"
+  CS_PAUSEDSYNCS = "PausedSyncS"
+  CS_PAUSEDSYNCT = "PausedSyncT"
+  CSET_SYNC = compat.UniqueFrozenset([
+    CS_WFREPORTPARAMS,
+    CS_STARTINGSYNCS,
+    CS_STARTINGSYNCT,
+    CS_WFBITMAPS,
+    CS_WFBITMAPT,
+    CS_WFSYNCUUID,
+    CS_SYNCSOURCE,
+    CS_SYNCTARGET,
+    CS_PAUSEDSYNCS,
+    CS_PAUSEDSYNCT,
+    ])
+
+  DS_DISKLESS = "Diskless"
+  DS_ATTACHING = "Attaching" # transient state
+  DS_FAILED = "Failed" # transient state, next: diskless
+  DS_NEGOTIATING = "Negotiating" # transient state
+  DS_INCONSISTENT = "Inconsistent" # while syncing or after creation
+  DS_OUTDATED = "Outdated"
+  DS_DUNKNOWN = "DUnknown" # shown for peer disk when not connected
+  DS_CONSISTENT = "Consistent"
+  DS_UPTODATE = "UpToDate" # normal state
+
+  RO_PRIMARY = "Primary"
+  RO_SECONDARY = "Secondary"
+  RO_UNKNOWN = "Unknown"
+
+  def __init__(self, procline):
+    u = self.UNCONF_RE.match(procline)
+    if u:
+      self.cstatus = self.CS_UNCONFIGURED
+      self.lrole = self.rrole = self.ldisk = self.rdisk = None
+    else:
+      m = self.LINE_RE.match(procline)
+      if not m:
+        raise errors.BlockDeviceError("Can't parse input data '%s'" % procline)
+      self.cstatus = m.group(1)
+      self.lrole = m.group(2)
+      self.rrole = m.group(3)
+      self.ldisk = m.group(4)
+      self.rdisk = m.group(5)
+
+    # end reading of data from the LINE_RE or UNCONF_RE
+
+    self.is_standalone = self.cstatus == self.CS_STANDALONE
+    self.is_wfconn = self.cstatus == self.CS_WFCONNECTION
+    self.is_connected = self.cstatus == self.CS_CONNECTED
+    self.is_primary = self.lrole == self.RO_PRIMARY
+    self.is_secondary = self.lrole == self.RO_SECONDARY
+    self.peer_primary = self.rrole == self.RO_PRIMARY
+    self.peer_secondary = self.rrole == self.RO_SECONDARY
+    self.both_primary = self.is_primary and self.peer_primary
+    self.both_secondary = self.is_secondary and self.peer_secondary
+
+    self.is_diskless = self.ldisk == self.DS_DISKLESS
+    self.is_disk_uptodate = self.ldisk == self.DS_UPTODATE
+
+    self.is_in_resync = self.cstatus in self.CSET_SYNC
+    self.is_in_use = self.cstatus != self.CS_UNCONFIGURED
+
+    m = self.SYNC_RE.match(procline)
+    if m:
+      self.sync_percent = float(m.group(1))
+      hours = int(m.group(2))
+      minutes = int(m.group(3))
+      seconds = int(m.group(4))
+      self.est_time = hours * 3600 + minutes * 60 + seconds
+    else:
+      # we have (in this if branch) no percent information, but if
+      # we're resyncing we need to 'fake' a sync percent information,
+      # as this is how cmdlib determines if it makes sense to wait for
+      # resyncing or not
+      if self.is_in_resync:
+        self.sync_percent = 0
+      else:
+        self.sync_percent = None
+      self.est_time = None
+
+
+class BaseDRBD(BlockDev): # pylint: disable=W0223
+  """Base DRBD class.
+
+  This class contains a few bits of common functionality between the
+  0.7 and 8.x versions of DRBD.
+
+  """
+  _VERSION_RE = re.compile(r"^version: (\d+)\.(\d+)\.(\d+)(?:\.\d+)?"
+                           r" \(api:(\d+)/proto:(\d+)(?:-(\d+))?\)")
+  _VALID_LINE_RE = re.compile("^ *([0-9]+): cs:([^ ]+).*$")
+  _UNUSED_LINE_RE = re.compile("^ *([0-9]+): cs:Unconfigured$")
+
+  _DRBD_MAJOR = 147
+  _ST_UNCONFIGURED = "Unconfigured"
+  _ST_WFCONNECTION = "WFConnection"
+  _ST_CONNECTED = "Connected"
+
+  _STATUS_FILE = constants.DRBD_STATUS_FILE
+  _USERMODE_HELPER_FILE = "/sys/module/drbd/parameters/usermode_helper"
+
+  @staticmethod
+  def _GetProcData(filename=_STATUS_FILE):
+    """Return data from /proc/drbd.
+
+    """
+    try:
+      data = utils.ReadFile(filename).splitlines()
+    except EnvironmentError, err:
+      if err.errno == errno.ENOENT:
+        _ThrowError("The file %s cannot be opened, check if the module"
+                    " is loaded (%s)", filename, str(err))
+      else:
+        _ThrowError("Can't read the DRBD proc file %s: %s", filename, str(err))
+    if not data:
+      _ThrowError("Can't read any data from %s", filename)
+    return data
+
+  @classmethod
+  def _MassageProcData(cls, data):
+    """Transform the output of _GetProdData into a nicer form.
+
+    @return: a dictionary of minor: joined lines from /proc/drbd
+        for that minor
+
+    """
+    results = {}
+    old_minor = old_line = None
+    for line in data:
+      if not line: # completely empty lines, as can be returned by drbd8.0+
+        continue
+      lresult = cls._VALID_LINE_RE.match(line)
+      if lresult is not None:
+        if old_minor is not None:
+          results[old_minor] = old_line
+        old_minor = int(lresult.group(1))
+        old_line = line
+      else:
+        if old_minor is not None:
+          old_line += " " + line.strip()
+    # add last line
+    if old_minor is not None:
+      results[old_minor] = old_line
+    return results
+
+  @classmethod
+  def _GetVersion(cls, proc_data):
+    """Return the DRBD version.
+
+    This will return a dict with keys:
+      - k_major
+      - k_minor
+      - k_point
+      - api
+      - proto
+      - proto2 (only on drbd > 8.2.X)
+
+    """
+    first_line = proc_data[0].strip()
+    version = cls._VERSION_RE.match(first_line)
+    if not version:
+      raise errors.BlockDeviceError("Can't parse DRBD version from '%s'" %
+                                    first_line)
+
+    values = version.groups()
+    retval = {
+      "k_major": int(values[0]),
+      "k_minor": int(values[1]),
+      "k_point": int(values[2]),
+      "api": int(values[3]),
+      "proto": int(values[4]),
+      }
+    if values[5] is not None:
+      retval["proto2"] = values[5]
+
+    return retval
+
+  @staticmethod
+  def GetUsermodeHelper(filename=_USERMODE_HELPER_FILE):
+    """Returns DRBD usermode_helper currently set.
+
+    """
+    try:
+      helper = utils.ReadFile(filename).splitlines()[0]
+    except EnvironmentError, err:
+      if err.errno == errno.ENOENT:
+        _ThrowError("The file %s cannot be opened, check if the module"
+                    " is loaded (%s)", filename, str(err))
+      else:
+        _ThrowError("Can't read DRBD helper file %s: %s", filename, str(err))
+    if not helper:
+      _ThrowError("Can't read any data from %s", filename)
+    return helper
+
+  @staticmethod
+  def _DevPath(minor):
+    """Return the path to a drbd device for a given minor.
+
+    """
+    return "/dev/drbd%d" % minor
+
+  @classmethod
+  def GetUsedDevs(cls):
+    """Compute the list of used DRBD devices.
+
+    """
+    data = cls._GetProcData()
+
+    used_devs = {}
+    for line in data:
+      match = cls._VALID_LINE_RE.match(line)
+      if not match:
+        continue
+      minor = int(match.group(1))
+      state = match.group(2)
+      if state == cls._ST_UNCONFIGURED:
+        continue
+      used_devs[minor] = state, line
+
+    return used_devs
+
+  def _SetFromMinor(self, minor):
+    """Set our parameters based on the given minor.
+
+    This sets our minor variable and our dev_path.
+
+    """
+    if minor is None:
+      self.minor = self.dev_path = None
+      self.attached = False
+    else:
+      self.minor = minor
+      self.dev_path = self._DevPath(minor)
+      self.attached = True
+
+  @staticmethod
+  def _CheckMetaSize(meta_device):
+    """Check if the given meta device looks like a valid one.
+
+    This currently only checks the size, which must be around
+    128MiB.
+
+    """
+    result = utils.RunCmd(["blockdev", "--getsize", meta_device])
+    if result.failed:
+      _ThrowError("Failed to get device size: %s - %s",
+                  result.fail_reason, result.output)
+    try:
+      sectors = int(result.stdout)
+    except (TypeError, ValueError):
+      _ThrowError("Invalid output from blockdev: '%s'", result.stdout)
+    num_bytes = sectors * 512
+    if num_bytes < 128 * 1024 * 1024: # less than 128MiB
+      _ThrowError("Meta device too small (%.2fMib)", (num_bytes / 1024 / 1024))
+    # the maximum *valid* size of the meta device when living on top
+    # of LVM is hard to compute: it depends on the number of stripes
+    # and the PE size; e.g. a 2-stripe, 64MB PE will result in a 128MB
+    # (normal size), but an eight-stripe 128MB PE will result in a 1GB
+    # size meta device; as such, we restrict it to 1GB (a little bit
+    # too generous, but making assumptions about PE size is hard)
+    if num_bytes > 1024 * 1024 * 1024:
+      _ThrowError("Meta device too big (%.2fMiB)", (num_bytes / 1024 / 1024))
+
+  def Rename(self, new_id):
+    """Rename a device.
+
+    This is not supported for drbd devices.
+
+    """
+    raise errors.ProgrammerError("Can't rename a drbd device")
+
+
+class DRBD8(BaseDRBD):
+  """DRBD v8.x block device.
+
+  This implements the local host part of the DRBD device, i.e. it
+  doesn't do anything to the supposed peer. If you need a fully
+  connected DRBD pair, you need to use this class on both hosts.
+
+  The unique_id for the drbd device is a (local_ip, local_port,
+  remote_ip, remote_port, local_minor, secret) tuple, and it must have
+  two children: the data device and the meta_device. The meta device
+  is checked for valid size and is zeroed on create.
+
+  """
+  _MAX_MINORS = 255
+  _PARSE_SHOW = None
+
+  # timeout constants
+  _NET_RECONFIG_TIMEOUT = 60
+
+  # command line options for barriers
+  _DISABLE_DISK_OPTION = "--no-disk-barrier"  # -a
+  _DISABLE_DRAIN_OPTION = "--no-disk-drain"   # -D
+  _DISABLE_FLUSH_OPTION = "--no-disk-flushes" # -i
+  _DISABLE_META_FLUSH_OPTION = "--no-md-flushes"  # -m
+
+  def __init__(self, unique_id, children, size, params):
+    if children and children.count(None) > 0:
+      children = []
+    if len(children) not in (0, 2):
+      raise ValueError("Invalid configuration data %s" % str(children))
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 6:
+      raise ValueError("Invalid configuration data %s" % str(unique_id))
+    (self._lhost, self._lport,
+     self._rhost, self._rport,
+     self._aminor, self._secret) = unique_id
+    if children:
+      if not _CanReadDevice(children[1].dev_path):
+        logging.info("drbd%s: Ignoring unreadable meta device", self._aminor)
+        children = []
+    super(DRBD8, self).__init__(unique_id, children, size, params)
+    self.major = self._DRBD_MAJOR
+    version = self._GetVersion(self._GetProcData())
+    if version["k_major"] != 8:
+      _ThrowError("Mismatch in DRBD kernel version and requested ganeti"
+                  " usage: kernel is %s.%s, ganeti wants 8.x",
+                  version["k_major"], version["k_minor"])
+
+    if (self._lhost is not None and self._lhost == self._rhost and
+        self._lport == self._rport):
+      raise ValueError("Invalid configuration data, same local/remote %s" %
+                       (unique_id,))
+    self.Attach()
+
+  @classmethod
+  def _InitMeta(cls, minor, dev_path):
+    """Initialize a meta device.
+
+    This will not work if the given minor is in use.
+
+    """
+    # Zero the metadata first, in order to make sure drbdmeta doesn't
+    # try to auto-detect existing filesystems or similar (see
+    # http://code.google.com/p/ganeti/issues/detail?id=182); we only
+    # care about the first 128MB of data in the device, even though it
+    # can be bigger
+    result = utils.RunCmd([constants.DD_CMD,
+                           "if=/dev/zero", "of=%s" % dev_path,
+                           "bs=1048576", "count=128", "oflag=direct"])
+    if result.failed:
+      _ThrowError("Can't wipe the meta device: %s", result.output)
+
+    result = utils.RunCmd(["drbdmeta", "--force", cls._DevPath(minor),
+                           "v08", dev_path, "0", "create-md"])
+    if result.failed:
+      _ThrowError("Can't initialize meta device: %s", result.output)
+
+  @classmethod
+  def _FindUnusedMinor(cls):
+    """Find an unused DRBD device.
+
+    This is specific to 8.x as the minors are allocated dynamically,
+    so non-existing numbers up to a max minor count are actually free.
+
+    """
+    data = cls._GetProcData()
+
+    highest = None
+    for line in data:
+      match = cls._UNUSED_LINE_RE.match(line)
+      if match:
+        return int(match.group(1))
+      match = cls._VALID_LINE_RE.match(line)
+      if match:
+        minor = int(match.group(1))
+        highest = max(highest, minor)
+    if highest is None: # there are no minors in use at all
+      return 0
+    if highest >= cls._MAX_MINORS:
+      logging.error("Error: no free drbd minors!")
+      raise errors.BlockDeviceError("Can't find a free DRBD minor")
+    return highest + 1
+
+  @classmethod
+  def _GetShowParser(cls):
+    """Return a parser for `drbd show` output.
+
+    This will either create or return an already-created parser for the
+    output of the command `drbd show`.
+
+    """
+    if cls._PARSE_SHOW is not None:
+      return cls._PARSE_SHOW
+
+    # pyparsing setup
+    lbrace = pyp.Literal("{").suppress()
+    rbrace = pyp.Literal("}").suppress()
+    lbracket = pyp.Literal("[").suppress()
+    rbracket = pyp.Literal("]").suppress()
+    semi = pyp.Literal(";").suppress()
+    colon = pyp.Literal(":").suppress()
+    # this also converts the value to an int
+    number = pyp.Word(pyp.nums).setParseAction(lambda s, l, t: int(t[0]))
+
+    comment = pyp.Literal("#") + pyp.Optional(pyp.restOfLine)
+    defa = pyp.Literal("_is_default").suppress()
+    dbl_quote = pyp.Literal('"').suppress()
+
+    keyword = pyp.Word(pyp.alphanums + "-")
+
+    # value types
+    value = pyp.Word(pyp.alphanums + "_-/.:")
+    quoted = dbl_quote + pyp.CharsNotIn('"') + dbl_quote
+    ipv4_addr = (pyp.Optional(pyp.Literal("ipv4")).suppress() +
+                 pyp.Word(pyp.nums + ".") + colon + number)
+    ipv6_addr = (pyp.Optional(pyp.Literal("ipv6")).suppress() +
+                 pyp.Optional(lbracket) + pyp.Word(pyp.hexnums + ":") +
+                 pyp.Optional(rbracket) + colon + number)
+    # meta device, extended syntax
+    meta_value = ((value ^ quoted) + lbracket + number + rbracket)
+    # device name, extended syntax
+    device_value = pyp.Literal("minor").suppress() + number
+
+    # a statement
+    stmt = (~rbrace + keyword + ~lbrace +
+            pyp.Optional(ipv4_addr ^ ipv6_addr ^ value ^ quoted ^ meta_value ^
+                         device_value) +
+            pyp.Optional(defa) + semi +
+            pyp.Optional(pyp.restOfLine).suppress())
+
+    # an entire section
+    section_name = pyp.Word(pyp.alphas + "_")
+    section = section_name + lbrace + pyp.ZeroOrMore(pyp.Group(stmt)) + rbrace
+
+    bnf = pyp.ZeroOrMore(pyp.Group(section ^ stmt))
+    bnf.ignore(comment)
+
+    cls._PARSE_SHOW = bnf
+
+    return bnf
+
+  @classmethod
+  def _GetShowData(cls, minor):
+    """Return the `drbdsetup show` data for a minor.
+
+    """
+    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "show"])
+    if result.failed:
+      logging.error("Can't display the drbd config: %s - %s",
+                    result.fail_reason, result.output)
+      return None
+    return result.stdout
+
+  @classmethod
+  def _GetDevInfo(cls, out):
+    """Parse details about a given DRBD minor.
+
+    This return, if available, the local backing device (as a path)
+    and the local and remote (ip, port) information from a string
+    containing the output of the `drbdsetup show` command as returned
+    by _GetShowData.
+
+    """
+    data = {}
+    if not out:
+      return data
+
+    bnf = cls._GetShowParser()
+    # run pyparse
+
+    try:
+      results = bnf.parseString(out)
+    except pyp.ParseException, err:
+      _ThrowError("Can't parse drbdsetup show output: %s", str(err))
+
+    # and massage the results into our desired format
+    for section in results:
+      sname = section[0]
+      if sname == "_this_host":
+        for lst in section[1:]:
+          if lst[0] == "disk":
+            data["local_dev"] = lst[1]
+          elif lst[0] == "meta-disk":
+            data["meta_dev"] = lst[1]
+            data["meta_index"] = lst[2]
+          elif lst[0] == "address":
+            data["local_addr"] = tuple(lst[1:])
+      elif sname == "_remote_host":
+        for lst in section[1:]:
+          if lst[0] == "address":
+            data["remote_addr"] = tuple(lst[1:])
+    return data
+
+  def _MatchesLocal(self, info):
+    """Test if our local config matches with an existing device.
+
+    The parameter should be as returned from `_GetDevInfo()`. This
+    method tests if our local backing device is the same as the one in
+    the info parameter, in effect testing if we look like the given
+    device.
+
+    """
+    if self._children:
+      backend, meta = self._children
+    else:
+      backend = meta = None
+
+    if backend is not None:
+      retval = ("local_dev" in info and info["local_dev"] == backend.dev_path)
+    else:
+      retval = ("local_dev" not in info)
+
+    if meta is not None:
+      retval = retval and ("meta_dev" in info and
+                           info["meta_dev"] == meta.dev_path)
+      retval = retval and ("meta_index" in info and
+                           info["meta_index"] == 0)
+    else:
+      retval = retval and ("meta_dev" not in info and
+                           "meta_index" not in info)
+    return retval
+
+  def _MatchesNet(self, info):
+    """Test if our network config matches with an existing device.
+
+    The parameter should be as returned from `_GetDevInfo()`. This
+    method tests if our network configuration is the same as the one
+    in the info parameter, in effect testing if we look like the given
+    device.
+
+    """
+    if (((self._lhost is None and not ("local_addr" in info)) and
+         (self._rhost is None and not ("remote_addr" in info)))):
+      return True
+
+    if self._lhost is None:
+      return False
+
+    if not ("local_addr" in info and
+            "remote_addr" in info):
+      return False
+
+    retval = (info["local_addr"] == (self._lhost, self._lport))
+    retval = (retval and
+              info["remote_addr"] == (self._rhost, self._rport))
+    return retval
+
+  def _AssembleLocal(self, minor, backend, meta, size):
+    """Configure the local part of a DRBD device.
+
+    """
+    args = ["drbdsetup", self._DevPath(minor), "disk",
+            backend, meta, "0",
+            "-e", "detach",
+            "--create-device"]
+    if size:
+      args.extend(["-d", "%sm" % size])
+
+    version = self._GetVersion(self._GetProcData())
+    vmaj = version["k_major"]
+    vmin = version["k_minor"]
+    vrel = version["k_point"]
+
+    barrier_args = \
+      self._ComputeDiskBarrierArgs(vmaj, vmin, vrel,
+                                   self.params[constants.LDP_BARRIERS],
+                                   self.params[constants.LDP_NO_META_FLUSH])
+    args.extend(barrier_args)
+
+    if self.params[constants.LDP_DISK_CUSTOM]:
+      args.extend(shlex.split(self.params[constants.LDP_DISK_CUSTOM]))
+
+    result = utils.RunCmd(args)
+    if result.failed:
+      _ThrowError("drbd%d: can't attach local disk: %s", minor, result.output)
+
+  @classmethod
+  def _ComputeDiskBarrierArgs(cls, vmaj, vmin, vrel, disabled_barriers,
+                              disable_meta_flush):
+    """Compute the DRBD command line parameters for disk barriers
+
+    Returns a list of the disk barrier parameters as requested via the
+    disabled_barriers and disable_meta_flush arguments, and according to the
+    supported ones in the DRBD version vmaj.vmin.vrel
+
+    If the desired option is unsupported, raises errors.BlockDeviceError.
+
+    """
+    disabled_barriers_set = frozenset(disabled_barriers)
+    if not disabled_barriers_set in constants.DRBD_VALID_BARRIER_OPT:
+      raise errors.BlockDeviceError("%s is not a valid option set for DRBD"
+                                    " barriers" % disabled_barriers)
+
+    args = []
+
+    # The following code assumes DRBD 8.x, with x < 4 and x != 1 (DRBD 8.1.x
+    # does not exist)
+    if not vmaj == 8 and vmin in (0, 2, 3):
+      raise errors.BlockDeviceError("Unsupported DRBD version: %d.%d.%d" %
+                                    (vmaj, vmin, vrel))
+
+    def _AppendOrRaise(option, min_version):
+      """Helper for DRBD options"""
+      if min_version is not None and vrel >= min_version:
+        args.append(option)
+      else:
+        raise errors.BlockDeviceError("Could not use the option %s as the"
+                                      " DRBD version %d.%d.%d does not support"
+                                      " it." % (option, vmaj, vmin, vrel))
+
+    # the minimum version for each feature is encoded via pairs of (minor
+    # version -> x) where x is version in which support for the option was
+    # introduced.
+    meta_flush_supported = disk_flush_supported = {
+      0: 12,
+      2: 7,
+      3: 0,
+      }
+
+    disk_drain_supported = {
+      2: 7,
+      3: 0,
+      }
+
+    disk_barriers_supported = {
+      3: 0,
+      }
+
+    # meta flushes
+    if disable_meta_flush:
+      _AppendOrRaise(cls._DISABLE_META_FLUSH_OPTION,
+                     meta_flush_supported.get(vmin, None))
+
+    # disk flushes
+    if constants.DRBD_B_DISK_FLUSH in disabled_barriers_set:
+      _AppendOrRaise(cls._DISABLE_FLUSH_OPTION,
+                     disk_flush_supported.get(vmin, None))
+
+    # disk drain
+    if constants.DRBD_B_DISK_DRAIN in disabled_barriers_set:
+      _AppendOrRaise(cls._DISABLE_DRAIN_OPTION,
+                     disk_drain_supported.get(vmin, None))
+
+    # disk barriers
+    if constants.DRBD_B_DISK_BARRIERS in disabled_barriers_set:
+      _AppendOrRaise(cls._DISABLE_DISK_OPTION,
+                     disk_barriers_supported.get(vmin, None))
+
+    return args
+
+  def _AssembleNet(self, minor, net_info, protocol,
+                   dual_pri=False, hmac=None, secret=None):
+    """Configure the network part of the device.
+
+    """
+    lhost, lport, rhost, rport = net_info
+    if None in net_info:
+      # we don't want network connection and actually want to make
+      # sure its shutdown
+      self._ShutdownNet(minor)
+      return
+
+    # Workaround for a race condition. When DRBD is doing its dance to
+    # establish a connection with its peer, it also sends the
+    # synchronization speed over the wire. In some cases setting the
+    # sync speed only after setting up both sides can race with DRBD
+    # connecting, hence we set it here before telling DRBD anything
+    # about its peer.
+    sync_errors = self._SetMinorSyncParams(minor, self.params)
+    if sync_errors:
+      _ThrowError("drbd%d: can't set the synchronization parameters: %s" %
+                  (minor, utils.CommaJoin(sync_errors)))
+
+    if netutils.IP6Address.IsValid(lhost):
+      if not netutils.IP6Address.IsValid(rhost):
+        _ThrowError("drbd%d: can't connect ip %s to ip %s" %
+                    (minor, lhost, rhost))
+      family = "ipv6"
+    elif netutils.IP4Address.IsValid(lhost):
+      if not netutils.IP4Address.IsValid(rhost):
+        _ThrowError("drbd%d: can't connect ip %s to ip %s" %
+                    (minor, lhost, rhost))
+      family = "ipv4"
+    else:
+      _ThrowError("drbd%d: Invalid ip %s" % (minor, lhost))
+
+    args = ["drbdsetup", self._DevPath(minor), "net",
+            "%s:%s:%s" % (family, lhost, lport),
+            "%s:%s:%s" % (family, rhost, rport), protocol,
+            "-A", "discard-zero-changes",
+            "-B", "consensus",
+            "--create-device",
+            ]
+    if dual_pri:
+      args.append("-m")
+    if hmac and secret:
+      args.extend(["-a", hmac, "-x", secret])
+
+    if self.params[constants.LDP_NET_CUSTOM]:
+      args.extend(shlex.split(self.params[constants.LDP_NET_CUSTOM]))
+
+    result = utils.RunCmd(args)
+    if result.failed:
+      _ThrowError("drbd%d: can't setup network: %s - %s",
+                  minor, result.fail_reason, result.output)
+
+    def _CheckNetworkConfig():
+      info = self._GetDevInfo(self._GetShowData(minor))
+      if not "local_addr" in info or not "remote_addr" in info:
+        raise utils.RetryAgain()
+
+      if (info["local_addr"] != (lhost, lport) or
+          info["remote_addr"] != (rhost, rport)):
+        raise utils.RetryAgain()
+
+    try:
+      utils.Retry(_CheckNetworkConfig, 1.0, 10.0)
+    except utils.RetryTimeout:
+      _ThrowError("drbd%d: timeout while configuring network", minor)
+
+  def AddChildren(self, devices):
+    """Add a disk to the DRBD device.
+
+    """
+    if self.minor is None:
+      _ThrowError("drbd%d: can't attach to dbrd8 during AddChildren",
+                  self._aminor)
+    if len(devices) != 2:
+      _ThrowError("drbd%d: need two devices for AddChildren", self.minor)
+    info = self._GetDevInfo(self._GetShowData(self.minor))
+    if "local_dev" in info:
+      _ThrowError("drbd%d: already attached to a local disk", self.minor)
+    backend, meta = devices
+    if backend.dev_path is None or meta.dev_path is None:
+      _ThrowError("drbd%d: children not ready during AddChildren", self.minor)
+    backend.Open()
+    meta.Open()
+    self._CheckMetaSize(meta.dev_path)
+    self._InitMeta(self._FindUnusedMinor(), meta.dev_path)
+
+    self._AssembleLocal(self.minor, backend.dev_path, meta.dev_path, self.size)
+    self._children = devices
+
+  def RemoveChildren(self, devices):
+    """Detach the drbd device from local storage.
+
+    """
+    if self.minor is None:
+      _ThrowError("drbd%d: can't attach to drbd8 during RemoveChildren",
+                  self._aminor)
+    # early return if we don't actually have backing storage
+    info = self._GetDevInfo(self._GetShowData(self.minor))
+    if "local_dev" not in info:
+      return
+    if len(self._children) != 2:
+      _ThrowError("drbd%d: we don't have two children: %s", self.minor,
+                  self._children)
+    if self._children.count(None) == 2: # we don't actually have children :)
+      logging.warning("drbd%d: requested detach while detached", self.minor)
+      return
+    if len(devices) != 2:
+      _ThrowError("drbd%d: we need two children in RemoveChildren", self.minor)
+    for child, dev in zip(self._children, devices):
+      if dev != child.dev_path:
+        _ThrowError("drbd%d: mismatch in local storage (%s != %s) in"
+                    " RemoveChildren", self.minor, dev, child.dev_path)
+
+    self._ShutdownLocal(self.minor)
+    self._children = []
+
+  @classmethod
+  def _SetMinorSyncParams(cls, minor, params):
+    """Set the parameters of the DRBD syncer.
+
+    This is the low-level implementation.
+
+    @type minor: int
+    @param minor: the drbd minor whose settings we change
+    @type params: dict
+    @param params: LD level disk parameters related to the synchronization
+    @rtype: list
+    @return: a list of error messages
+
+    """
+
+    args = ["drbdsetup", cls._DevPath(minor), "syncer"]
+    if params[constants.LDP_DYNAMIC_RESYNC]:
+      version = cls._GetVersion(cls._GetProcData())
+      vmin = version["k_minor"]
+      vrel = version["k_point"]
+
+      # By definition we are using 8.x, so just check the rest of the version
+      # number
+      if vmin != 3 or vrel < 9:
+        msg = ("The current DRBD version (8.%d.%d) does not support the "
+               "dynamic resync speed controller" % (vmin, vrel))
+        logging.error(msg)
+        return [msg]
+
+      if params[constants.LDP_PLAN_AHEAD] == 0:
+        msg = ("A value of 0 for c-plan-ahead disables the dynamic sync speed"
+               " controller at DRBD level. If you want to disable it, please"
+               " set the dynamic-resync disk parameter to False.")
+        logging.error(msg)
+        return [msg]
+
+      # add the c-* parameters to args
+      args.extend(["--c-plan-ahead", params[constants.LDP_PLAN_AHEAD],
+                   "--c-fill-target", params[constants.LDP_FILL_TARGET],
+                   "--c-delay-target", params[constants.LDP_DELAY_TARGET],
+                   "--c-max-rate", params[constants.LDP_MAX_RATE],
+                   "--c-min-rate", params[constants.LDP_MIN_RATE],
+                   ])
+
+    else:
+      args.extend(["-r", "%d" % params[constants.LDP_RESYNC_RATE]])
+
+    args.append("--create-device")
+    result = utils.RunCmd(args)
+    if result.failed:
+      msg = ("Can't change syncer rate: %s - %s" %
+             (result.fail_reason, result.output))
+      logging.error(msg)
+      return [msg]
+
+    return []
+
+  def SetSyncParams(self, params):
+    """Set the synchronization parameters of the DRBD syncer.
+
+    @type params: dict
+    @param params: LD level disk parameters related to the synchronization
+    @rtype: list
+    @return: a list of error messages, emitted both by the current node and by
+    children. An empty list means no errors
+
+    """
+    if self.minor is None:
+      err = "Not attached during SetSyncParams"
+      logging.info(err)
+      return [err]
+
+    children_result = super(DRBD8, self).SetSyncParams(params)
+    children_result.extend(self._SetMinorSyncParams(self.minor, params))
+    return children_result
+
+  def PauseResumeSync(self, pause):
+    """Pauses or resumes the sync of a DRBD device.
+
+    @param pause: Wether to pause or resume
+    @return: the success of the operation
+
+    """
+    if self.minor is None:
+      logging.info("Not attached during PauseSync")
+      return False
+
+    children_result = super(DRBD8, self).PauseResumeSync(pause)
+
+    if pause:
+      cmd = "pause-sync"
+    else:
+      cmd = "resume-sync"
+
+    result = utils.RunCmd(["drbdsetup", self.dev_path, cmd])
+    if result.failed:
+      logging.error("Can't %s: %s - %s", cmd,
+                    result.fail_reason, result.output)
+    return not result.failed and children_result
+
+  def GetProcStatus(self):
+    """Return device data from /proc.
+
+    """
+    if self.minor is None:
+      _ThrowError("drbd%d: GetStats() called while not attached", self._aminor)
+    proc_info = self._MassageProcData(self._GetProcData())
+    if self.minor not in proc_info:
+      _ThrowError("drbd%d: can't find myself in /proc", self.minor)
+    return DRBD8Status(proc_info[self.minor])
+
+  def GetSyncStatus(self):
+    """Returns the sync status of the device.
+
+
+    If sync_percent is None, it means all is ok
+    If estimated_time is None, it means we can't estimate
+    the time needed, otherwise it's the time left in seconds.
+
+
+    We set the is_degraded parameter to True on two conditions:
+    network not connected or local disk missing.
+
+    We compute the ldisk parameter based on whether we have a local
+    disk or not.
+
+    @rtype: objects.BlockDevStatus
+
+    """
+    if self.minor is None and not self.Attach():
+      _ThrowError("drbd%d: can't Attach() in GetSyncStatus", self._aminor)
+
+    stats = self.GetProcStatus()
+    is_degraded = not stats.is_connected or not stats.is_disk_uptodate
+
+    if stats.is_disk_uptodate:
+      ldisk_status = constants.LDS_OKAY
+    elif stats.is_diskless:
+      ldisk_status = constants.LDS_FAULTY
+    else:
+      ldisk_status = constants.LDS_UNKNOWN
+
+    return objects.BlockDevStatus(dev_path=self.dev_path,
+                                  major=self.major,
+                                  minor=self.minor,
+                                  sync_percent=stats.sync_percent,
+                                  estimated_time=stats.est_time,
+                                  is_degraded=is_degraded,
+                                  ldisk_status=ldisk_status)
+
+  def Open(self, force=False):
+    """Make the local state primary.
+
+    If the 'force' parameter is given, the '-o' option is passed to
+    drbdsetup. Since this is a potentially dangerous operation, the
+    force flag should be only given after creation, when it actually
+    is mandatory.
+
+    """
+    if self.minor is None and not self.Attach():
+      logging.error("DRBD cannot attach to a device during open")
+      return False
+    cmd = ["drbdsetup", self.dev_path, "primary"]
+    if force:
+      cmd.append("-o")
+    result = utils.RunCmd(cmd)
+    if result.failed:
+      _ThrowError("drbd%d: can't make drbd device primary: %s", self.minor,
+                  result.output)
+
+  def Close(self):
+    """Make the local state secondary.
+
+    This will, of course, fail if the device is in use.
+
+    """
+    if self.minor is None and not self.Attach():
+      _ThrowError("drbd%d: can't Attach() in Close()", self._aminor)
+    result = utils.RunCmd(["drbdsetup", self.dev_path, "secondary"])
+    if result.failed:
+      _ThrowError("drbd%d: can't switch drbd device to secondary: %s",
+                  self.minor, result.output)
+
+  def DisconnectNet(self):
+    """Removes network configuration.
+
+    This method shutdowns the network side of the device.
+
+    The method will wait up to a hardcoded timeout for the device to
+    go into standalone after the 'disconnect' command before
+    re-configuring it, as sometimes it takes a while for the
+    disconnect to actually propagate and thus we might issue a 'net'
+    command while the device is still connected. If the device will
+    still be attached to the network and we time out, we raise an
+    exception.
+
+    """
+    if self.minor is None:
+      _ThrowError("drbd%d: disk not attached in re-attach net", self._aminor)
+
+    if None in (self._lhost, self._lport, self._rhost, self._rport):
+      _ThrowError("drbd%d: DRBD disk missing network info in"
+                  " DisconnectNet()", self.minor)
+
+    class _DisconnectStatus:
+      def __init__(self, ever_disconnected):
+        self.ever_disconnected = ever_disconnected
+
+    dstatus = _DisconnectStatus(_IgnoreError(self._ShutdownNet, self.minor))
+
+    def _WaitForDisconnect():
+      if self.GetProcStatus().is_standalone:
+        return
+
+      # retry the disconnect, it seems possible that due to a well-time
+      # disconnect on the peer, my disconnect command might be ignored and
+      # forgotten
+      dstatus.ever_disconnected = \
+        _IgnoreError(self._ShutdownNet, self.minor) or dstatus.ever_disconnected
+
+      raise utils.RetryAgain()
+
+    # Keep start time
+    start_time = time.time()
+
+    try:
+      # Start delay at 100 milliseconds and grow up to 2 seconds
+      utils.Retry(_WaitForDisconnect, (0.1, 1.5, 2.0),
+                  self._NET_RECONFIG_TIMEOUT)
+    except utils.RetryTimeout:
+      if dstatus.ever_disconnected:
+        msg = ("drbd%d: device did not react to the"
+               " 'disconnect' command in a timely manner")
+      else:
+        msg = "drbd%d: can't shutdown network, even after multiple retries"
+
+      _ThrowError(msg, self.minor)
+
+    reconfig_time = time.time() - start_time
+    if reconfig_time > (self._NET_RECONFIG_TIMEOUT * 0.25):
+      logging.info("drbd%d: DisconnectNet: detach took %.3f seconds",
+                   self.minor, reconfig_time)
+
+  def AttachNet(self, multimaster):
+    """Reconnects the network.
+
+    This method connects the network side of the device with a
+    specified multi-master flag. The device needs to be 'Standalone'
+    but have valid network configuration data.
+
+    Args:
+      - multimaster: init the network in dual-primary mode
+
+    """
+    if self.minor is None:
+      _ThrowError("drbd%d: device not attached in AttachNet", self._aminor)
+
+    if None in (self._lhost, self._lport, self._rhost, self._rport):
+      _ThrowError("drbd%d: missing network info in AttachNet()", self.minor)
+
+    status = self.GetProcStatus()
+
+    if not status.is_standalone:
+      _ThrowError("drbd%d: device is not standalone in AttachNet", self.minor)
+
+    self._AssembleNet(self.minor,
+                      (self._lhost, self._lport, self._rhost, self._rport),
+                      constants.DRBD_NET_PROTOCOL, dual_pri=multimaster,
+                      hmac=constants.DRBD_HMAC_ALG, secret=self._secret)
+
+  def Attach(self):
+    """Check if our minor is configured.
+
+    This doesn't do any device configurations - it only checks if the
+    minor is in a state different from Unconfigured.
+
+    Note that this function will not change the state of the system in
+    any way (except in case of side-effects caused by reading from
+    /proc).
+
+    """
+    used_devs = self.GetUsedDevs()
+    if self._aminor in used_devs:
+      minor = self._aminor
+    else:
+      minor = None
+
+    self._SetFromMinor(minor)
+    return minor is not None
+
+  def Assemble(self):
+    """Assemble the drbd.
+
+    Method:
+      - if we have a configured device, we try to ensure that it matches
+        our config
+      - if not, we create it from zero
+      - anyway, set the device parameters
+
+    """
+    super(DRBD8, self).Assemble()
+
+    self.Attach()
+    if self.minor is None:
+      # local device completely unconfigured
+      self._FastAssemble()
+    else:
+      # we have to recheck the local and network status and try to fix
+      # the device
+      self._SlowAssemble()
+
+    sync_errors = self.SetSyncParams(self.params)
+    if sync_errors:
+      _ThrowError("drbd%d: can't set the synchronization parameters: %s" %
+                  (self.minor, utils.CommaJoin(sync_errors)))
+
+  def _SlowAssemble(self):
+    """Assembles the DRBD device from a (partially) configured device.
+
+    In case of partially attached (local device matches but no network
+    setup), we perform the network attach. If successful, we re-test
+    the attach if can return success.
+
+    """
+    # TODO: Rewrite to not use a for loop just because there is 'break'
+    # pylint: disable=W0631
+    net_data = (self._lhost, self._lport, self._rhost, self._rport)
+    for minor in (self._aminor,):
+      info = self._GetDevInfo(self._GetShowData(minor))
+      match_l = self._MatchesLocal(info)
+      match_r = self._MatchesNet(info)
+
+      if match_l and match_r:
+        # everything matches
+        break
+
+      if match_l and not match_r and "local_addr" not in info:
+        # disk matches, but not attached to network, attach and recheck
+        self._AssembleNet(minor, net_data, constants.DRBD_NET_PROTOCOL,
+                          hmac=constants.DRBD_HMAC_ALG, secret=self._secret)
+        if self._MatchesNet(self._GetDevInfo(self._GetShowData(minor))):
+          break
+        else:
+          _ThrowError("drbd%d: network attach successful, but 'drbdsetup"
+                      " show' disagrees", minor)
+
+      if match_r and "local_dev" not in info:
+        # no local disk, but network attached and it matches
+        self._AssembleLocal(minor, self._children[0].dev_path,
+                            self._children[1].dev_path, self.size)
+        if self._MatchesNet(self._GetDevInfo(self._GetShowData(minor))):
+          break
+        else:
+          _ThrowError("drbd%d: disk attach successful, but 'drbdsetup"
+                      " show' disagrees", minor)
+
+      # this case must be considered only if we actually have local
+      # storage, i.e. not in diskless mode, because all diskless
+      # devices are equal from the point of view of local
+      # configuration
+      if (match_l and "local_dev" in info and
+          not match_r and "local_addr" in info):
+        # strange case - the device network part points to somewhere
+        # else, even though its local storage is ours; as we own the
+        # drbd space, we try to disconnect from the remote peer and
+        # reconnect to our correct one
+        try:
+          self._ShutdownNet(minor)
+        except errors.BlockDeviceError, err:
+          _ThrowError("drbd%d: device has correct local storage, wrong"
+                      " remote peer and is unable to disconnect in order"
+                      " to attach to the correct peer: %s", minor, str(err))
+        # note: _AssembleNet also handles the case when we don't want
+        # local storage (i.e. one or more of the _[lr](host|port) is
+        # None)
+        self._AssembleNet(minor, net_data, constants.DRBD_NET_PROTOCOL,
+                          hmac=constants.DRBD_HMAC_ALG, secret=self._secret)
+        if self._MatchesNet(self._GetDevInfo(self._GetShowData(minor))):
+          break
+        else:
+          _ThrowError("drbd%d: network attach successful, but 'drbdsetup"
+                      " show' disagrees", minor)
+
+    else:
+      minor = None
+
+    self._SetFromMinor(minor)
+    if minor is None:
+      _ThrowError("drbd%d: cannot activate, unknown or unhandled reason",
+                  self._aminor)
+
+  def _FastAssemble(self):
+    """Assemble the drbd device from zero.
+
+    This is run when in Assemble we detect our minor is unused.
+
+    """
+    minor = self._aminor
+    if self._children and self._children[0] and self._children[1]:
+      self._AssembleLocal(minor, self._children[0].dev_path,
+                          self._children[1].dev_path, self.size)
+    if self._lhost and self._lport and self._rhost and self._rport:
+      self._AssembleNet(minor,
+                        (self._lhost, self._lport, self._rhost, self._rport),
+                        constants.DRBD_NET_PROTOCOL,
+                        hmac=constants.DRBD_HMAC_ALG, secret=self._secret)
+    self._SetFromMinor(minor)
+
+  @classmethod
+  def _ShutdownLocal(cls, minor):
+    """Detach from the local device.
+
+    I/Os will continue to be served from the remote device. If we
+    don't have a remote device, this operation will fail.
+
+    """
+    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "detach"])
+    if result.failed:
+      _ThrowError("drbd%d: can't detach local disk: %s", minor, result.output)
+
+  @classmethod
+  def _ShutdownNet(cls, minor):
+    """Disconnect from the remote peer.
+
+    This fails if we don't have a local device.
+
+    """
+    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "disconnect"])
+    if result.failed:
+      _ThrowError("drbd%d: can't shutdown network: %s", minor, result.output)
+
+  @classmethod
+  def _ShutdownAll(cls, minor):
+    """Deactivate the device.
+
+    This will, of course, fail if the device is in use.
+
+    """
+    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "down"])
+    if result.failed:
+      _ThrowError("drbd%d: can't shutdown drbd device: %s",
+                  minor, result.output)
+
+  def Shutdown(self):
+    """Shutdown the DRBD device.
+
+    """
+    if self.minor is None and not self.Attach():
+      logging.info("drbd%d: not attached during Shutdown()", self._aminor)
+      return
+    minor = self.minor
+    self.minor = None
+    self.dev_path = None
+    self._ShutdownAll(minor)
+
+  def Remove(self):
+    """Stub remove for DRBD devices.
+
+    """
+    self.Shutdown()
+
+  @classmethod
+  def Create(cls, unique_id, children, size, params, excl_stor):
+    """Create a new DRBD8 device.
+
+    Since DRBD devices are not created per se, just assembled, this
+    function only initializes the metadata.
+
+    """
+    if len(children) != 2:
+      raise errors.ProgrammerError("Invalid setup for the drbd device")
+    if excl_stor:
+      raise errors.ProgrammerError("DRBD device requested with"
+                                   " exclusive_storage")
+    # check that the minor is unused
+    aminor = unique_id[4]
+    proc_info = cls._MassageProcData(cls._GetProcData())
+    if aminor in proc_info:
+      status = DRBD8Status(proc_info[aminor])
+      in_use = status.is_in_use
+    else:
+      in_use = False
+    if in_use:
+      _ThrowError("drbd%d: minor is already in use at Create() time", aminor)
+    meta = children[1]
+    meta.Assemble()
+    if not meta.Attach():
+      _ThrowError("drbd%d: can't attach to meta device '%s'",
+                  aminor, meta)
+    cls._CheckMetaSize(meta.dev_path)
+    cls._InitMeta(aminor, meta.dev_path)
+    return cls(unique_id, children, size, params)
+
+  def Grow(self, amount, dryrun, backingstore):
+    """Resize the DRBD device and its backing storage.
+
+    """
+    if self.minor is None:
+      _ThrowError("drbd%d: Grow called while not attached", self._aminor)
+    if len(self._children) != 2 or None in self._children:
+      _ThrowError("drbd%d: cannot grow diskless device", self.minor)
+    self._children[0].Grow(amount, dryrun, backingstore)
+    if dryrun or backingstore:
+      # DRBD does not support dry-run mode and is not backing storage,
+      # so we'll return here
+      return
+    result = utils.RunCmd(["drbdsetup", self.dev_path, "resize", "-s",
+                           "%dm" % (self.size + amount)])
+    if result.failed:
+      _ThrowError("drbd%d: resize failed: %s", self.minor, result.output)
+
+
+class FileStorage(BlockDev):
+  """File device.
+
+  This class represents the a file storage backend device.
+
+  The unique_id for the file device is a (file_driver, file_path) tuple.
+
+  """
+  def __init__(self, unique_id, children, size, params):
+    """Initalizes a file device backend.
+
+    """
+    if children:
+      raise errors.BlockDeviceError("Invalid setup for file device")
+    super(FileStorage, self).__init__(unique_id, children, size, params)
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise ValueError("Invalid configuration data %s" % str(unique_id))
+    self.driver = unique_id[0]
+    self.dev_path = unique_id[1]
+
+    CheckFileStoragePath(self.dev_path)
+
+    self.Attach()
+
+  def Assemble(self):
+    """Assemble the device.
+
+    Checks whether the file device exists, raises BlockDeviceError otherwise.
+
+    """
+    if not os.path.exists(self.dev_path):
+      _ThrowError("File device '%s' does not exist" % self.dev_path)
+
+  def Shutdown(self):
+    """Shutdown the device.
+
+    This is a no-op for the file type, as we don't deactivate
+    the file on shutdown.
+
+    """
+    pass
+
+  def Open(self, force=False):
+    """Make the device ready for I/O.
+
+    This is a no-op for the file type.
+
+    """
+    pass
+
+  def Close(self):
+    """Notifies that the device will no longer be used for I/O.
+
+    This is a no-op for the file type.
+
+    """
+    pass
+
+  def Remove(self):
+    """Remove the file backing the block device.
+
+    @rtype: boolean
+    @return: True if the removal was successful
+
+    """
+    try:
+      os.remove(self.dev_path)
+    except OSError, err:
+      if err.errno != errno.ENOENT:
+        _ThrowError("Can't remove file '%s': %s", self.dev_path, err)
+
+  def Rename(self, new_id):
+    """Renames the file.
+
+    """
+    # TODO: implement rename for file-based storage
+    _ThrowError("Rename is not supported for file-based storage")
+
+  def Grow(self, amount, dryrun, backingstore):
+    """Grow the file
+
+    @param amount: the amount (in mebibytes) to grow with
+
+    """
+    if not backingstore:
+      return
+    # Check that the file exists
+    self.Assemble()
+    current_size = self.GetActualSize()
+    new_size = current_size + amount * 1024 * 1024
+    assert new_size > current_size, "Cannot Grow with a negative amount"
+    # We can't really simulate the growth
+    if dryrun:
+      return
+    try:
+      f = open(self.dev_path, "a+")
+      f.truncate(new_size)
+      f.close()
+    except EnvironmentError, err:
+      _ThrowError("Error in file growth: %", str(err))
+
+  def Attach(self):
+    """Attach to an existing file.
+
+    Check if this file already exists.
+
+    @rtype: boolean
+    @return: True if file exists
+
+    """
+    self.attached = os.path.exists(self.dev_path)
+    return self.attached
+
+  def GetActualSize(self):
+    """Return the actual disk size.
+
+    @note: the device needs to be active when this is called
+
+    """
+    assert self.attached, "BlockDevice not attached in GetActualSize()"
+    try:
+      st = os.stat(self.dev_path)
+      return st.st_size
+    except OSError, err:
+      _ThrowError("Can't stat %s: %s", self.dev_path, err)
+
+  @classmethod
+  def Create(cls, unique_id, children, size, params, excl_stor):
+    """Create a new file.
+
+    @param size: the size of file in MiB
+
+    @rtype: L{bdev.FileStorage}
+    @return: an instance of FileStorage
+
+    """
+    if excl_stor:
+      raise errors.ProgrammerError("FileStorage device requested with"
+                                   " exclusive_storage")
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise ValueError("Invalid configuration data %s" % str(unique_id))
+
+    dev_path = unique_id[1]
+
+    CheckFileStoragePath(dev_path)
+
+    try:
+      fd = os.open(dev_path, os.O_RDWR | os.O_CREAT | os.O_EXCL)
+      f = os.fdopen(fd, "w")
+      f.truncate(size * 1024 * 1024)
+      f.close()
+    except EnvironmentError, err:
+      if err.errno == errno.EEXIST:
+        _ThrowError("File already existing: %s", dev_path)
+      _ThrowError("Error in file creation: %", str(err))
+
+    return FileStorage(unique_id, children, size, params)
+
+
+class PersistentBlockDevice(BlockDev):
+  """A block device with persistent node
+
+  May be either directly attached, or exposed through DM (e.g. dm-multipath).
+  udev helpers are probably required to give persistent, human-friendly
+  names.
+
+  For the time being, pathnames are required to lie under /dev.
+
+  """
+  def __init__(self, unique_id, children, size, params):
+    """Attaches to a static block device.
+
+    The unique_id is a path under /dev.
+
+    """
+    super(PersistentBlockDevice, self).__init__(unique_id, children, size,
+                                                params)
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise ValueError("Invalid configuration data %s" % str(unique_id))
+    self.dev_path = unique_id[1]
+    if not os.path.realpath(self.dev_path).startswith("/dev/"):
+      raise ValueError("Full path '%s' lies outside /dev" %
+                              os.path.realpath(self.dev_path))
+    # TODO: this is just a safety guard checking that we only deal with devices
+    # we know how to handle. In the future this will be integrated with
+    # external storage backends and possible values will probably be collected
+    # from the cluster configuration.
+    if unique_id[0] != constants.BLOCKDEV_DRIVER_MANUAL:
+      raise ValueError("Got persistent block device of invalid type: %s" %
+                       unique_id[0])
+
+    self.major = self.minor = None
+    self.Attach()
+
+  @classmethod
+  def Create(cls, unique_id, children, size, params, excl_stor):
+    """Create a new device
+
+    This is a noop, we only return a PersistentBlockDevice instance
+
+    """
+    if excl_stor:
+      raise errors.ProgrammerError("Persistent block device requested with"
+                                   " exclusive_storage")
+    return PersistentBlockDevice(unique_id, children, 0, params)
+
+  def Remove(self):
+    """Remove a device
+
+    This is a noop
+
+    """
+    pass
+
+  def Rename(self, new_id):
+    """Rename this device.
+
+    """
+    _ThrowError("Rename is not supported for PersistentBlockDev storage")
+
+  def Attach(self):
+    """Attach to an existing block device.
+
+
+    """
+    self.attached = False
+    try:
+      st = os.stat(self.dev_path)
+    except OSError, err:
+      logging.error("Error stat()'ing %s: %s", self.dev_path, str(err))
+      return False
+
+    if not stat.S_ISBLK(st.st_mode):
+      logging.error("%s is not a block device", self.dev_path)
+      return False
+
+    self.major = os.major(st.st_rdev)
+    self.minor = os.minor(st.st_rdev)
+    self.attached = True
+
+    return True
+
+  def Assemble(self):
+    """Assemble the device.
+
+    """
+    pass
+
+  def Shutdown(self):
+    """Shutdown the device.
+
+    """
+    pass
+
+  def Open(self, force=False):
+    """Make the device ready for I/O.
+
+    """
+    pass
+
+  def Close(self):
+    """Notifies that the device will no longer be used for I/O.
+
+    """
+    pass
+
+  def Grow(self, amount, dryrun, backingstore):
+    """Grow the logical volume.
+
+    """
+    _ThrowError("Grow is not supported for PersistentBlockDev storage")
+
+
+class RADOSBlockDevice(BlockDev):
+  """A RADOS Block Device (rbd).
+
+  This class implements the RADOS Block Device for the backend. You need
+  the rbd kernel driver, the RADOS Tools and a working RADOS cluster for
+  this to be functional.
+
+  """
+  def __init__(self, unique_id, children, size, params):
+    """Attaches to an rbd device.
+
+    """
+    super(RADOSBlockDevice, self).__init__(unique_id, children, size, params)
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise ValueError("Invalid configuration data %s" % str(unique_id))
+
+    self.driver, self.rbd_name = unique_id
+
+    self.major = self.minor = None
+    self.Attach()
+
+  @classmethod
+  def Create(cls, unique_id, children, size, params, excl_stor):
+    """Create a new rbd device.
+
+    Provision a new rbd volume inside a RADOS pool.
+
+    """
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise errors.ProgrammerError("Invalid configuration data %s" %
+                                   str(unique_id))
+    if excl_stor:
+      raise errors.ProgrammerError("RBD device requested with"
+                                   " exclusive_storage")
+    rbd_pool = params[constants.LDP_POOL]
+    rbd_name = unique_id[1]
+
+    # Provision a new rbd volume (Image) inside the RADOS cluster.
+    cmd = [constants.RBD_CMD, "create", "-p", rbd_pool,
+           rbd_name, "--size", "%s" % size]
+    result = utils.RunCmd(cmd)
+    if result.failed:
+      _ThrowError("rbd creation failed (%s): %s",
+                  result.fail_reason, result.output)
+
+    return RADOSBlockDevice(unique_id, children, size, params)
+
+  def Remove(self):
+    """Remove the rbd device.
+
+    """
+    rbd_pool = self.params[constants.LDP_POOL]
+    rbd_name = self.unique_id[1]
+
+    if not self.minor and not self.Attach():
+      # The rbd device doesn't exist.
+      return
+
+    # First shutdown the device (remove mappings).
+    self.Shutdown()
+
+    # Remove the actual Volume (Image) from the RADOS cluster.
+    cmd = [constants.RBD_CMD, "rm", "-p", rbd_pool, rbd_name]
+    result = utils.RunCmd(cmd)
+    if result.failed:
+      _ThrowError("Can't remove Volume from cluster with rbd rm: %s - %s",
+                  result.fail_reason, result.output)
+
+  def Rename(self, new_id):
+    """Rename this device.
+
+    """
+    pass
+
+  def Attach(self):
+    """Attach to an existing rbd device.
+
+    This method maps the rbd volume that matches our name with
+    an rbd device and then attaches to this device.
+
+    """
+    self.attached = False
+
+    # Map the rbd volume to a block device under /dev
+    self.dev_path = self._MapVolumeToBlockdev(self.unique_id)
+
+    try:
+      st = os.stat(self.dev_path)
+    except OSError, err:
+      logging.error("Error stat()'ing %s: %s", self.dev_path, str(err))
+      return False
+
+    if not stat.S_ISBLK(st.st_mode):
+      logging.error("%s is not a block device", self.dev_path)
+      return False
+
+    self.major = os.major(st.st_rdev)
+    self.minor = os.minor(st.st_rdev)
+    self.attached = True
+
+    return True
+
+  def _MapVolumeToBlockdev(self, unique_id):
+    """Maps existing rbd volumes to block devices.
+
+    This method should be idempotent if the mapping already exists.
+
+    @rtype: string
+    @return: the block device path that corresponds to the volume
+
+    """
+    pool = self.params[constants.LDP_POOL]
+    name = unique_id[1]
+
+    # Check if the mapping already exists.
+    rbd_dev = self._VolumeToBlockdev(pool, name)
+    if rbd_dev:
+      # The mapping exists. Return it.
+      return rbd_dev
+
+    # The mapping doesn't exist. Create it.
+    map_cmd = [constants.RBD_CMD, "map", "-p", pool, name]
+    result = utils.RunCmd(map_cmd)
+    if result.failed:
+      _ThrowError("rbd map failed (%s): %s",
+                  result.fail_reason, result.output)
+
+    # Find the corresponding rbd device.
+    rbd_dev = self._VolumeToBlockdev(pool, name)
+    if not rbd_dev:
+      _ThrowError("rbd map succeeded, but could not find the rbd block"
+                  " device in output of showmapped, for volume: %s", name)
+
+    # The device was successfully mapped. Return it.
+    return rbd_dev
+
+  @classmethod
+  def _VolumeToBlockdev(cls, pool, volume_name):
+    """Do the 'volume name'-to-'rbd block device' resolving.
+
+    @type pool: string
+    @param pool: RADOS pool to use
+    @type volume_name: string
+    @param volume_name: the name of the volume whose device we search for
+    @rtype: string or None
+    @return: block device path if the volume is mapped, else None
+
+    """
+    try:
+      # Newer versions of the rbd tool support json output formatting. Use it
+      # if available.
+      showmap_cmd = [
+        constants.RBD_CMD,
+        "showmapped",
+        "-p",
+        pool,
+        "--format",
+        "json"
+        ]
+      result = utils.RunCmd(showmap_cmd)
+      if result.failed:
+        logging.error("rbd JSON output formatting returned error (%s): %s,"
+                      "falling back to plain output parsing",
+                      result.fail_reason, result.output)
+        raise RbdShowmappedJsonError
+
+      return cls._ParseRbdShowmappedJson(result.output, volume_name)
+    except RbdShowmappedJsonError:
+      # For older versions of rbd, we have to parse the plain / text output
+      # manually.
+      showmap_cmd = [constants.RBD_CMD, "showmapped", "-p", pool]
+      result = utils.RunCmd(showmap_cmd)
+      if result.failed:
+        _ThrowError("rbd showmapped failed (%s): %s",
+                    result.fail_reason, result.output)
+
+      return cls._ParseRbdShowmappedPlain(result.output, volume_name)
+
+  @staticmethod
+  def _ParseRbdShowmappedJson(output, volume_name):
+    """Parse the json output of `rbd showmapped'.
+
+    This method parses the json output of `rbd showmapped' and returns the rbd
+    block device path (e.g. /dev/rbd0) that matches the given rbd volume.
+
+    @type output: string
+    @param output: the json output of `rbd showmapped'
+    @type volume_name: string
+    @param volume_name: the name of the volume whose device we search for
+    @rtype: string or None
+    @return: block device path if the volume is mapped, else None
+
+    """
+    try:
+      devices = serializer.LoadJson(output)
+    except ValueError, err:
+      _ThrowError("Unable to parse JSON data: %s" % err)
+
+    rbd_dev = None
+    for d in devices.values(): # pylint: disable=E1103
+      try:
+        name = d["name"]
+      except KeyError:
+        _ThrowError("'name' key missing from json object %s", devices)
+
+      if name == volume_name:
+        if rbd_dev is not None:
+          _ThrowError("rbd volume %s is mapped more than once", volume_name)
+
+        rbd_dev = d["device"]
+
+    return rbd_dev
+
+  @staticmethod
+  def _ParseRbdShowmappedPlain(output, volume_name):
+    """Parse the (plain / text) output of `rbd showmapped'.
+
+    This method parses the output of `rbd showmapped' and returns
+    the rbd block device path (e.g. /dev/rbd0) that matches the
+    given rbd volume.
+
+    @type output: string
+    @param output: the plain text output of `rbd showmapped'
+    @type volume_name: string
+    @param volume_name: the name of the volume whose device we search for
+    @rtype: string or None
+    @return: block device path if the volume is mapped, else None
+
+    """
+    allfields = 5
+    volumefield = 2
+    devicefield = 4
+
+    lines = output.splitlines()
+
+    # Try parsing the new output format (ceph >= 0.55).
+    splitted_lines = map(lambda l: l.split(), lines)
+
+    # Check for empty output.
+    if not splitted_lines:
+      return None
+
+    # Check showmapped output, to determine number of fields.
+    field_cnt = len(splitted_lines[0])
+    if field_cnt != allfields:
+      # Parsing the new format failed. Fallback to parsing the old output
+      # format (< 0.55).
+      splitted_lines = map(lambda l: l.split("\t"), lines)
+      if field_cnt != allfields:
+        _ThrowError("Cannot parse rbd showmapped output expected %s fields,"
+                    " found %s", allfields, field_cnt)
+
+    matched_lines = \
+      filter(lambda l: len(l) == allfields and l[volumefield] == volume_name,
+             splitted_lines)
+
+    if len(matched_lines) > 1:
+      _ThrowError("rbd volume %s mapped more than once", volume_name)
+
+    if matched_lines:
+      # rbd block device found. Return it.
+      rbd_dev = matched_lines[0][devicefield]
+      return rbd_dev
+
+    # The given volume is not mapped.
+    return None
+
+  def Assemble(self):
+    """Assemble the device.
+
+    """
+    pass
+
+  def Shutdown(self):
+    """Shutdown the device.
+
+    """
+    if not self.minor and not self.Attach():
+      # The rbd device doesn't exist.
+      return
+
+    # Unmap the block device from the Volume.
+    self._UnmapVolumeFromBlockdev(self.unique_id)
+
+    self.minor = None
+    self.dev_path = None
+
+  def _UnmapVolumeFromBlockdev(self, unique_id):
+    """Unmaps the rbd device from the Volume it is mapped.
+
+    Unmaps the rbd device from the Volume it was previously mapped to.
+    This method should be idempotent if the Volume isn't mapped.
+
+    """
+    pool = self.params[constants.LDP_POOL]
+    name = unique_id[1]
+
+    # Check if the mapping already exists.
+    rbd_dev = self._VolumeToBlockdev(pool, name)
+
+    if rbd_dev:
+      # The mapping exists. Unmap the rbd device.
+      unmap_cmd = [constants.RBD_CMD, "unmap", "%s" % rbd_dev]
+      result = utils.RunCmd(unmap_cmd)
+      if result.failed:
+        _ThrowError("rbd unmap failed (%s): %s",
+                    result.fail_reason, result.output)
+
+  def Open(self, force=False):
+    """Make the device ready for I/O.
+
+    """
+    pass
+
+  def Close(self):
+    """Notifies that the device will no longer be used for I/O.
+
+    """
+    pass
+
+  def Grow(self, amount, dryrun, backingstore):
+    """Grow the Volume.
+
+    @type amount: integer
+    @param amount: the amount (in mebibytes) to grow with
+    @type dryrun: boolean
+    @param dryrun: whether to execute the operation in simulation mode
+        only, without actually increasing the size
+
+    """
+    if not backingstore:
+      return
+    if not self.Attach():
+      _ThrowError("Can't attach to rbd device during Grow()")
+
+    if dryrun:
+      # the rbd tool does not support dry runs of resize operations.
+      # Since rbd volumes are thinly provisioned, we assume
+      # there is always enough free space for the operation.
+      return
+
+    rbd_pool = self.params[constants.LDP_POOL]
+    rbd_name = self.unique_id[1]
+    new_size = self.size + amount
+
+    # Resize the rbd volume (Image) inside the RADOS cluster.
+    cmd = [constants.RBD_CMD, "resize", "-p", rbd_pool,
+           rbd_name, "--size", "%s" % new_size]
+    result = utils.RunCmd(cmd)
+    if result.failed:
+      _ThrowError("rbd resize failed (%s): %s",
+                  result.fail_reason, result.output)
+
+
+class ExtStorageDevice(BlockDev):
+  """A block device provided by an ExtStorage Provider.
+
+  This class implements the External Storage Interface, which means
+  handling of the externally provided block devices.
+
+  """
+  def __init__(self, unique_id, children, size, params):
+    """Attaches to an extstorage block device.
+
+    """
+    super(ExtStorageDevice, self).__init__(unique_id, children, size, params)
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise ValueError("Invalid configuration data %s" % str(unique_id))
+
+    self.driver, self.vol_name = unique_id
+    self.ext_params = params
+
+    self.major = self.minor = None
+    self.Attach()
+
+  @classmethod
+  def Create(cls, unique_id, children, size, params, excl_stor):
+    """Create a new extstorage device.
+
+    Provision a new volume using an extstorage provider, which will
+    then be mapped to a block device.
+
+    """
+    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+      raise errors.ProgrammerError("Invalid configuration data %s" %
+                                   str(unique_id))
+    if excl_stor:
+      raise errors.ProgrammerError("extstorage device requested with"
+                                   " exclusive_storage")
+
+    # Call the External Storage's create script,
+    # to provision a new Volume inside the External Storage
+    _ExtStorageAction(constants.ES_ACTION_CREATE, unique_id,
+                      params, str(size))
+
+    return ExtStorageDevice(unique_id, children, size, params)
+
+  def Remove(self):
+    """Remove the extstorage device.
+
+    """
+    if not self.minor and not self.Attach():
+      # The extstorage device doesn't exist.
+      return
+
+    # First shutdown the device (remove mappings).
+    self.Shutdown()
+
+    # Call the External Storage's remove script,
+    # to remove the Volume from the External Storage
+    _ExtStorageAction(constants.ES_ACTION_REMOVE, self.unique_id,
+                      self.ext_params)
+
+  def Rename(self, new_id):
+    """Rename this device.
+
+    """
+    pass
+
+  def Attach(self):
+    """Attach to an existing extstorage device.
+
+    This method maps the extstorage volume that matches our name with
+    a corresponding block device and then attaches to this device.
+
+    """
+    self.attached = False
+
+    # Call the External Storage's attach script,
+    # to attach an existing Volume to a block device under /dev
+    self.dev_path = _ExtStorageAction(constants.ES_ACTION_ATTACH,
+                                      self.unique_id, self.ext_params)
+
+    try:
+      st = os.stat(self.dev_path)
+    except OSError, err:
+      logging.error("Error stat()'ing %s: %s", self.dev_path, str(err))
+      return False
+
+    if not stat.S_ISBLK(st.st_mode):
+      logging.error("%s is not a block device", self.dev_path)
+      return False
+
+    self.major = os.major(st.st_rdev)
+    self.minor = os.minor(st.st_rdev)
+    self.attached = True
+
+    return True
+
+  def Assemble(self):
+    """Assemble the device.
+
+    """
+    pass
+
+  def Shutdown(self):
+    """Shutdown the device.
+
+    """
+    if not self.minor and not self.Attach():
+      # The extstorage device doesn't exist.
+      return
+
+    # Call the External Storage's detach script,
+    # to detach an existing Volume from it's block device under /dev
+    _ExtStorageAction(constants.ES_ACTION_DETACH, self.unique_id,
+                      self.ext_params)
+
+    self.minor = None
+    self.dev_path = None
+
+  def Open(self, force=False):
+    """Make the device ready for I/O.
+
+    """
+    pass
+
+  def Close(self):
+    """Notifies that the device will no longer be used for I/O.
+
+    """
+    pass
+
+  def Grow(self, amount, dryrun, backingstore):
+    """Grow the Volume.
+
+    @type amount: integer
+    @param amount: the amount (in mebibytes) to grow with
+    @type dryrun: boolean
+    @param dryrun: whether to execute the operation in simulation mode
+        only, without actually increasing the size
+
+    """
+    if not backingstore:
+      return
+    if not self.Attach():
+      _ThrowError("Can't attach to extstorage device during Grow()")
+
+    if dryrun:
+      # we do not support dry runs of resize operations for now.
+      return
+
+    new_size = self.size + amount
+
+    # Call the External Storage's grow script,
+    # to grow an existing Volume inside the External Storage
+    _ExtStorageAction(constants.ES_ACTION_GROW, self.unique_id,
+                      self.ext_params, str(self.size), grow=str(new_size))
+
+  def SetInfo(self, text):
+    """Update metadata with info text.
+
+    """
+    # Replace invalid characters
+    text = re.sub("^[^A-Za-z0-9_+.]", "_", text)
+    text = re.sub("[^-A-Za-z0-9_+.]", "_", text)
+
+    # Only up to 128 characters are allowed
+    text = text[:128]
+
+    # Call the External Storage's setinfo script,
+    # to set metadata for an existing Volume inside the External Storage
+    _ExtStorageAction(constants.ES_ACTION_SETINFO, self.unique_id,
+                      self.ext_params, metadata=text)
+
+
+def _ExtStorageAction(action, unique_id, ext_params,
+                      size=None, grow=None, metadata=None):
+  """Take an External Storage action.
+
+  Take an External Storage action concerning or affecting
+  a specific Volume inside the External Storage.
+
+  @type action: string
+  @param action: which action to perform. One of:
+                 create / remove / grow / attach / detach
+  @type unique_id: tuple (driver, vol_name)
+  @param unique_id: a tuple containing the type of ExtStorage (driver)
+                    and the Volume name
+  @type ext_params: dict
+  @param ext_params: ExtStorage parameters
+  @type size: integer
+  @param size: the size of the Volume in mebibytes
+  @type grow: integer
+  @param grow: the new size in mebibytes (after grow)
+  @type metadata: string
+  @param metadata: metadata info of the Volume, for use by the provider
+  @rtype: None or a block device path (during attach)
+
+  """
+  driver, vol_name = unique_id
+
+  # Create an External Storage instance of type `driver'
+  status, inst_es = ExtStorageFromDisk(driver)
+  if not status:
+    _ThrowError("%s" % inst_es)
+
+  # Create the basic environment for the driver's scripts
+  create_env = _ExtStorageEnvironment(unique_id, ext_params, size,
+                                      grow, metadata)
+
+  # Do not use log file for action `attach' as we need
+  # to get the output from RunResult
+  # TODO: find a way to have a log file for attach too
+  logfile = None
+  if action is not constants.ES_ACTION_ATTACH:
+    logfile = _VolumeLogName(action, driver, vol_name)
+
+  # Make sure the given action results in a valid script
+  if action not in constants.ES_SCRIPTS:
+    _ThrowError("Action '%s' doesn't result in a valid ExtStorage script" %
+                action)
+
+  # Find out which external script to run according the given action
+  script_name = action + "_script"
+  script = getattr(inst_es, script_name)
+
+  # Run the external script
+  result = utils.RunCmd([script], env=create_env,
+                        cwd=inst_es.path, output=logfile,)
+  if result.failed:
+    logging.error("External storage's %s command '%s' returned"
+                  " error: %s, logfile: %s, output: %s",
+                  action, result.cmd, result.fail_reason,
+                  logfile, result.output)
+
+    # If logfile is 'None' (during attach), it breaks TailFile
+    # TODO: have a log file for attach too
+    if action is not constants.ES_ACTION_ATTACH:
+      lines = [utils.SafeEncode(val)
+               for val in utils.TailFile(logfile, lines=20)]
+    else:
+      lines = result.output[-20:]
+
+    _ThrowError("External storage's %s script failed (%s), last"
+                " lines of output:\n%s",
+                action, result.fail_reason, "\n".join(lines))
+
+  if action == constants.ES_ACTION_ATTACH:
+    return result.stdout
+
+
+def ExtStorageFromDisk(name, base_dir=None):
+  """Create an ExtStorage instance from disk.
+
+  This function will return an ExtStorage instance
+  if the given name is a valid ExtStorage name.
+
+  @type base_dir: string
+  @keyword base_dir: Base directory containing ExtStorage installations.
+                     Defaults to a search in all the ES_SEARCH_PATH dirs.
+  @rtype: tuple
+  @return: True and the ExtStorage instance if we find a valid one, or
+      False and the diagnose message on error
+
+  """
+  if base_dir is None:
+    es_base_dir = pathutils.ES_SEARCH_PATH
+  else:
+    es_base_dir = [base_dir]
+
+  es_dir = utils.FindFile(name, es_base_dir, os.path.isdir)
+
+  if es_dir is None:
+    return False, ("Directory for External Storage Provider %s not"
+                   " found in search path" % name)
+
+  # ES Files dictionary, we will populate it with the absolute path
+  # names; if the value is True, then it is a required file, otherwise
+  # an optional one
+  es_files = dict.fromkeys(constants.ES_SCRIPTS, True)
+
+  es_files[constants.ES_PARAMETERS_FILE] = True
+
+  for (filename, _) in es_files.items():
+    es_files[filename] = utils.PathJoin(es_dir, filename)
+
+    try:
+      st = os.stat(es_files[filename])
+    except EnvironmentError, err:
+      return False, ("File '%s' under path '%s' is missing (%s)" %
+                     (filename, es_dir, utils.ErrnoOrStr(err)))
+
+    if not stat.S_ISREG(stat.S_IFMT(st.st_mode)):
+      return False, ("File '%s' under path '%s' is not a regular file" %
+                     (filename, es_dir))
+
+    if filename in constants.ES_SCRIPTS:
+      if stat.S_IMODE(st.st_mode) & stat.S_IXUSR != stat.S_IXUSR:
+        return False, ("File '%s' under path '%s' is not executable" %
+                       (filename, es_dir))
+
+  parameters = []
+  if constants.ES_PARAMETERS_FILE in es_files:
+    parameters_file = es_files[constants.ES_PARAMETERS_FILE]
+    try:
+      parameters = utils.ReadFile(parameters_file).splitlines()
+    except EnvironmentError, err:
+      return False, ("Error while reading the EXT parameters file at %s: %s" %
+                     (parameters_file, utils.ErrnoOrStr(err)))
+    parameters = [v.split(None, 1) for v in parameters]
+
+  es_obj = \
+    objects.ExtStorage(name=name, path=es_dir,
+                       create_script=es_files[constants.ES_SCRIPT_CREATE],
+                       remove_script=es_files[constants.ES_SCRIPT_REMOVE],
+                       grow_script=es_files[constants.ES_SCRIPT_GROW],
+                       attach_script=es_files[constants.ES_SCRIPT_ATTACH],
+                       detach_script=es_files[constants.ES_SCRIPT_DETACH],
+                       setinfo_script=es_files[constants.ES_SCRIPT_SETINFO],
+                       verify_script=es_files[constants.ES_SCRIPT_VERIFY],
+                       supported_parameters=parameters)
+  return True, es_obj
+
+
+def _ExtStorageEnvironment(unique_id, ext_params,
+                           size=None, grow=None, metadata=None):
+  """Calculate the environment for an External Storage script.
+
+  @type unique_id: tuple (driver, vol_name)
+  @param unique_id: ExtStorage pool and name of the Volume
+  @type ext_params: dict
+  @param ext_params: the EXT parameters
+  @type size: string
+  @param size: size of the Volume (in mebibytes)
+  @type grow: string
+  @param grow: new size of Volume after grow (in mebibytes)
+  @type metadata: string
+  @param metadata: metadata info of the Volume
+  @rtype: dict
+  @return: dict of environment variables
+
+  """
+  vol_name = unique_id[1]
+
+  result = {}
+  result["VOL_NAME"] = vol_name
+
+  # EXT params
+  for pname, pvalue in ext_params.items():
+    result["EXTP_%s" % pname.upper()] = str(pvalue)
+
+  if size is not None:
+    result["VOL_SIZE"] = size
+
+  if grow is not None:
+    result["VOL_NEW_SIZE"] = grow
+
+  if metadata is not None:
+    result["VOL_METADATA"] = metadata
+
+  return result
+
+
+def _VolumeLogName(kind, es_name, volume):
+  """Compute the ExtStorage log filename for a given Volume and operation.
+
+  @type kind: string
+  @param kind: the operation type (e.g. create, remove etc.)
+  @type es_name: string
+  @param es_name: the ExtStorage name
+  @type volume: string
+  @param volume: the name of the Volume inside the External Storage
+
+  """
+  # Check if the extstorage log dir is a valid dir
+  if not os.path.isdir(pathutils.LOG_ES_DIR):
+    _ThrowError("Cannot find log directory: %s", pathutils.LOG_ES_DIR)
+
+  # TODO: Use tempfile.mkstemp to create unique filename
+  base = ("%s-%s-%s-%s.log" %
+          (kind, es_name, volume, utils.TimestampForFilename()))
+  return utils.PathJoin(pathutils.LOG_ES_DIR, base)
+
+
+DEV_MAP = {
+  constants.LD_LV: LogicalVolume,
+  constants.LD_DRBD8: DRBD8,
+  constants.LD_BLOCKDEV: PersistentBlockDevice,
+  constants.LD_RBD: RADOSBlockDevice,
+  constants.LD_EXT: ExtStorageDevice,
+  }
+
+if constants.ENABLE_FILE_STORAGE or constants.ENABLE_SHARED_FILE_STORAGE:
+  DEV_MAP[constants.LD_FILE] = FileStorage
+
+
+def _VerifyDiskType(dev_type):
+  if dev_type not in DEV_MAP:
+    raise errors.ProgrammerError("Invalid block device type '%s'" % dev_type)
+
+
+def _VerifyDiskParams(disk):
+  """Verifies if all disk parameters are set.
+
+  """
+  missing = set(constants.DISK_LD_DEFAULTS[disk.dev_type]) - set(disk.params)
+  if missing:
+    raise errors.ProgrammerError("Block device is missing disk parameters: %s" %
+                                 missing)
+
+
+def FindDevice(disk, children):
+  """Search for an existing, assembled device.
+
+  This will succeed only if the device exists and is assembled, but it
+  does not do any actions in order to activate the device.
+
+  @type disk: L{objects.Disk}
+  @param disk: the disk object to find
+  @type children: list of L{bdev.BlockDev}
+  @param children: the list of block devices that are children of the device
+                  represented by the disk parameter
+
+  """
+  _VerifyDiskType(disk.dev_type)
+  device = DEV_MAP[disk.dev_type](disk.physical_id, children, disk.size,
+                                  disk.params)
+  if not device.attached:
+    return None
+  return device
+
+
+def Assemble(disk, children):
+  """Try to attach or assemble an existing device.
+
+  This will attach to assemble the device, as needed, to bring it
+  fully up. It must be safe to run on already-assembled devices.
+
+  @type disk: L{objects.Disk}
+  @param disk: the disk object to assemble
+  @type children: list of L{bdev.BlockDev}
+  @param children: the list of block devices that are children of the device
+                  represented by the disk parameter
+
+  """
+  _VerifyDiskType(disk.dev_type)
+  _VerifyDiskParams(disk)
+  device = DEV_MAP[disk.dev_type](disk.physical_id, children, disk.size,
+                                  disk.params)
+  device.Assemble()
+  return device
+
+
+def Create(disk, children, excl_stor):
+  """Create a device.
+
+  @type disk: L{objects.Disk}
+  @param disk: the disk object to create
+  @type children: list of L{bdev.BlockDev}
+  @param children: the list of block devices that are children of the device
+                  represented by the disk parameter
+  @type excl_stor: boolean
+  @param excl_stor: Whether exclusive_storage is active
+
+  """
+  _VerifyDiskType(disk.dev_type)
+  _VerifyDiskParams(disk)
+  device = DEV_MAP[disk.dev_type].Create(disk.physical_id, children, disk.size,
+                                         disk.params, excl_stor)
+  return device
diff --git a/lib/bootstrap.py b/lib/bootstrap.py
index 40da336..2183d6b 100644
--- a/lib/bootstrap.py
+++ b/lib/bootstrap.py
@@ -40,7 +40,7 @@ from ganeti import objects
 from ganeti import ssconf
 from ganeti import serializer
 from ganeti import hypervisor
-from ganeti import bdev
+from ganeti.block import bdev
 from ganeti import netutils
 from ganeti import luxi
 from ganeti import jstore
diff --git a/lib/hypervisor/hv_xen.py b/lib/hypervisor/hv_xen.py
index 8789571..77d323f 100644
--- a/lib/hypervisor/hv_xen.py
+++ b/lib/hypervisor/hv_xen.py
@@ -270,7 +270,7 @@ def _GetConfigFileDiskData(block_devices, blockdev_prefix,
 
   @param block_devices: list of tuples (cfdev, rldev):
       - cfdev: dict containing ganeti config disk part
-      - rldev: ganeti.bdev.BlockDev object
+      - rldev: ganeti.block.bdev.BlockDev object
   @param blockdev_prefix: a string containing blockdevice prefix,
                           e.g. "sd" for /dev/sda
 
diff --git a/lib/watcher/nodemaint.py b/lib/watcher/nodemaint.py
index 6cb2a48..a0a8300 100644
--- a/lib/watcher/nodemaint.py
+++ b/lib/watcher/nodemaint.py
@@ -25,7 +25,6 @@
 
 import logging
 
-from ganeti import bdev
 from ganeti import constants
 from ganeti import errors
 from ganeti import hypervisor
@@ -33,6 +32,7 @@ from ganeti import netutils
 from ganeti import ssconf
 from ganeti import utils
 from ganeti import confd
+from ganeti.block import bdev
 
 import ganeti.confd.client # pylint: disable=W0611
 
diff --git a/test/py/ganeti.bdev_unittest.py b/test/py/ganeti.bdev_unittest.py
deleted file mode 100755
index 8243375..0000000
--- a/test/py/ganeti.bdev_unittest.py
+++ /dev/null
@@ -1,613 +0,0 @@
-#!/usr/bin/python
-#
-
-# Copyright (C) 2006, 2007, 2010, 2012, 2013 Google Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful, but
-# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-# 02110-1301, USA.
-
-
-"""Script for unittesting the bdev module"""
-
-
-import os
-import random
-import unittest
-
-from ganeti import bdev
-from ganeti import compat
-from ganeti import constants
-from ganeti import errors
-from ganeti import objects
-from ganeti import utils
-
-import testutils
-
-
-class TestBaseDRBD(testutils.GanetiTestCase):
-  def testGetVersion(self):
-    data = [
-      ["version: 8.0.12 (api:76/proto:86-91)"],
-      ["version: 8.2.7 (api:88/proto:0-100)"],
-      ["version: 8.3.7.49 (api:188/proto:13-191)"],
-    ]
-    result = [
-      {
-      "k_major": 8,
-      "k_minor": 0,
-      "k_point": 12,
-      "api": 76,
-      "proto": 86,
-      "proto2": "91",
-      },
-      {
-      "k_major": 8,
-      "k_minor": 2,
-      "k_point": 7,
-      "api": 88,
-      "proto": 0,
-      "proto2": "100",
-      },
-      {
-      "k_major": 8,
-      "k_minor": 3,
-      "k_point": 7,
-      "api": 188,
-      "proto": 13,
-      "proto2": "191",
-      }
-    ]
-    for d,r in zip(data, result):
-      self.assertEqual(bdev.BaseDRBD._GetVersion(d), r)
-
-
-class TestDRBD8Runner(testutils.GanetiTestCase):
-  """Testing case for DRBD8"""
-
-  @staticmethod
-  def _has_disk(data, dname, mname):
-    """Check local disk corectness"""
-    retval = (
-      "local_dev" in data and
-      data["local_dev"] == dname and
-      "meta_dev" in data and
-      data["meta_dev"] == mname and
-      "meta_index" in data and
-      data["meta_index"] == 0
-      )
-    return retval
-
-  @staticmethod
-  def _has_net(data, local, remote):
-    """Check network connection parameters"""
-    retval = (
-      "local_addr" in data and
-      data["local_addr"] == local and
-      "remote_addr" in data and
-      data["remote_addr"] == remote
-      )
-    return retval
-
-  def testParserCreation(self):
-    """Test drbdsetup show parser creation"""
-    bdev.DRBD8._GetShowParser()
-
-  def testParser80(self):
-    """Test drbdsetup show parser for disk and network version 8.0"""
-    data = testutils.ReadTestData("bdev-drbd-8.0.txt")
-    result = bdev.DRBD8._GetDevInfo(data)
-    self.failUnless(self._has_disk(result, "/dev/xenvg/test.data",
-                                   "/dev/xenvg/test.meta"),
-                    "Wrong local disk info")
-    self.failUnless(self._has_net(result, ("192.0.2.1", 11000),
-                                  ("192.0.2.2", 11000)),
-                    "Wrong network info (8.0.x)")
-
-  def testParser83(self):
-    """Test drbdsetup show parser for disk and network version 8.3"""
-    data = testutils.ReadTestData("bdev-drbd-8.3.txt")
-    result = bdev.DRBD8._GetDevInfo(data)
-    self.failUnless(self._has_disk(result, "/dev/xenvg/test.data",
-                                   "/dev/xenvg/test.meta"),
-                    "Wrong local disk info")
-    self.failUnless(self._has_net(result, ("192.0.2.1", 11000),
-                                  ("192.0.2.2", 11000)),
-                    "Wrong network info (8.0.x)")
-
-  def testParserNetIP4(self):
-    """Test drbdsetup show parser for IPv4 network"""
-    data = testutils.ReadTestData("bdev-drbd-net-ip4.txt")
-    result = bdev.DRBD8._GetDevInfo(data)
-    self.failUnless(("local_dev" not in result and
-                     "meta_dev" not in result and
-                     "meta_index" not in result),
-                    "Should not find local disk info")
-    self.failUnless(self._has_net(result, ("192.0.2.1", 11002),
-                                  ("192.0.2.2", 11002)),
-                    "Wrong network info (IPv4)")
-
-  def testParserNetIP6(self):
-    """Test drbdsetup show parser for IPv6 network"""
-    data = testutils.ReadTestData("bdev-drbd-net-ip6.txt")
-    result = bdev.DRBD8._GetDevInfo(data)
-    self.failUnless(("local_dev" not in result and
-                     "meta_dev" not in result and
-                     "meta_index" not in result),
-                    "Should not find local disk info")
-    self.failUnless(self._has_net(result, ("2001:db8:65::1", 11048),
-                                  ("2001:db8:66::1", 11048)),
-                    "Wrong network info (IPv6)")
-
-  def testParserDisk(self):
-    """Test drbdsetup show parser for disk"""
-    data = testutils.ReadTestData("bdev-drbd-disk.txt")
-    result = bdev.DRBD8._GetDevInfo(data)
-    self.failUnless(self._has_disk(result, "/dev/xenvg/test.data",
-                                   "/dev/xenvg/test.meta"),
-                    "Wrong local disk info")
-    self.failUnless(("local_addr" not in result and
-                     "remote_addr" not in result),
-                    "Should not find network info")
-
-  def testBarriersOptions(self):
-    """Test class method that generates drbdsetup options for disk barriers"""
-    # Tests that should fail because of wrong version/options combinations
-    should_fail = [
-      (8, 0, 12, "bfd", True),
-      (8, 0, 12, "fd", False),
-      (8, 0, 12, "b", True),
-      (8, 2, 7, "bfd", True),
-      (8, 2, 7, "b", True)
-    ]
-
-    for vmaj, vmin, vrel, opts, meta in should_fail:
-      self.assertRaises(errors.BlockDeviceError,
-                        bdev.DRBD8._ComputeDiskBarrierArgs,
-                        vmaj, vmin, vrel, opts, meta)
-
-    # get the valid options from the frozenset(frozenset()) in constants.
-    valid_options = [list(x)[0] for x in constants.DRBD_VALID_BARRIER_OPT]
-
-    # Versions that do not support anything
-    for vmaj, vmin, vrel in ((8, 0, 0), (8, 0, 11), (8, 2, 6)):
-      for opts in valid_options:
-        self.assertRaises(errors.BlockDeviceError,
-                          bdev.DRBD8._ComputeDiskBarrierArgs,
-                          vmaj, vmin, vrel, opts, True)
-
-    # Versions with partial support (testing only options that are supported)
-    tests = [
-      (8, 0, 12, "n", False, []),
-      (8, 0, 12, "n", True, ["--no-md-flushes"]),
-      (8, 2, 7, "n", False, []),
-      (8, 2, 7, "fd", False, ["--no-disk-flushes", "--no-disk-drain"]),
-      (8, 0, 12, "n", True, ["--no-md-flushes"]),
-      ]
-
-    # Versions that support everything
-    for vmaj, vmin, vrel in ((8, 3, 0), (8, 3, 12)):
-      tests.append((vmaj, vmin, vrel, "bfd", True,
-                    ["--no-disk-barrier", "--no-disk-drain",
-                     "--no-disk-flushes", "--no-md-flushes"]))
-      tests.append((vmaj, vmin, vrel, "n", False, []))
-      tests.append((vmaj, vmin, vrel, "b", True,
-                    ["--no-disk-barrier", "--no-md-flushes"]))
-      tests.append((vmaj, vmin, vrel, "fd", False,
-                    ["--no-disk-flushes", "--no-disk-drain"]))
-      tests.append((vmaj, vmin, vrel, "n", True, ["--no-md-flushes"]))
-
-    # Test execution
-    for test in tests:
-      vmaj, vmin, vrel, disabled_barriers, disable_meta_flush, expected = test
-      args = \
-        bdev.DRBD8._ComputeDiskBarrierArgs(vmaj, vmin, vrel,
-                                           disabled_barriers,
-                                           disable_meta_flush)
-      self.failUnless(set(args) == set(expected),
-                      "For test %s, got wrong results %s" % (test, args))
-
-    # Unsupported or invalid versions
-    for vmaj, vmin, vrel in ((0, 7, 25), (9, 0, 0), (7, 0, 0), (8, 4, 0)):
-      self.assertRaises(errors.BlockDeviceError,
-                        bdev.DRBD8._ComputeDiskBarrierArgs,
-                        vmaj, vmin, vrel, "n", True)
-
-    # Invalid options
-    for option in ("", "c", "whatever", "nbdfc", "nf"):
-      self.assertRaises(errors.BlockDeviceError,
-                        bdev.DRBD8._ComputeDiskBarrierArgs,
-                        8, 3, 11, option, True)
-
-
-class TestDRBD8Status(testutils.GanetiTestCase):
-  """Testing case for DRBD8 /proc status"""
-
-  def setUp(self):
-    """Read in txt data"""
-    testutils.GanetiTestCase.setUp(self)
-    proc_data = testutils.TestDataFilename("proc_drbd8.txt")
-    proc80e_data = testutils.TestDataFilename("proc_drbd80-emptyline.txt")
-    proc83_data = testutils.TestDataFilename("proc_drbd83.txt")
-    proc83_sync_data = testutils.TestDataFilename("proc_drbd83_sync.txt")
-    proc83_sync_krnl_data = \
-      testutils.TestDataFilename("proc_drbd83_sync_krnl2.6.39.txt")
-    self.proc_data = bdev.DRBD8._GetProcData(filename=proc_data)
-    self.proc80e_data = bdev.DRBD8._GetProcData(filename=proc80e_data)
-    self.proc83_data = bdev.DRBD8._GetProcData(filename=proc83_data)
-    self.proc83_sync_data = bdev.DRBD8._GetProcData(filename=proc83_sync_data)
-    self.proc83_sync_krnl_data = \
-      bdev.DRBD8._GetProcData(filename=proc83_sync_krnl_data)
-    self.mass_data = bdev.DRBD8._MassageProcData(self.proc_data)
-    self.mass80e_data = bdev.DRBD8._MassageProcData(self.proc80e_data)
-    self.mass83_data = bdev.DRBD8._MassageProcData(self.proc83_data)
-    self.mass83_sync_data = bdev.DRBD8._MassageProcData(self.proc83_sync_data)
-    self.mass83_sync_krnl_data = \
-      bdev.DRBD8._MassageProcData(self.proc83_sync_krnl_data)
-
-  def testIOErrors(self):
-    """Test handling of errors while reading the proc file."""
-    temp_file = self._CreateTempFile()
-    os.unlink(temp_file)
-    self.failUnlessRaises(errors.BlockDeviceError,
-                          bdev.DRBD8._GetProcData, filename=temp_file)
-
-  def testHelper(self):
-    """Test reading usermode_helper in /sys."""
-    sys_drbd_helper = testutils.TestDataFilename("sys_drbd_usermode_helper.txt")
-    drbd_helper = bdev.DRBD8.GetUsermodeHelper(filename=sys_drbd_helper)
-    self.failUnlessEqual(drbd_helper, "/bin/true")
-
-  def testHelperIOErrors(self):
-    """Test handling of errors while reading usermode_helper in /sys."""
-    temp_file = self._CreateTempFile()
-    os.unlink(temp_file)
-    self.failUnlessRaises(errors.BlockDeviceError,
-                          bdev.DRBD8.GetUsermodeHelper, filename=temp_file)
-
-  def testMinorNotFound(self):
-    """Test not-found-minor in /proc"""
-    self.failUnless(9 not in self.mass_data)
-    self.failUnless(9 not in self.mass83_data)
-    self.failUnless(3 not in self.mass80e_data)
-
-  def testLineNotMatch(self):
-    """Test wrong line passed to DRBD8Status"""
-    self.assertRaises(errors.BlockDeviceError, bdev.DRBD8Status, "foo")
-
-  def testMinor0(self):
-    """Test connected, primary device"""
-    for data in [self.mass_data, self.mass83_data]:
-      stats = bdev.DRBD8Status(data[0])
-      self.failUnless(stats.is_in_use)
-      self.failUnless(stats.is_connected and stats.is_primary and
-                      stats.peer_secondary and stats.is_disk_uptodate)
-
-  def testMinor1(self):
-    """Test connected, secondary device"""
-    for data in [self.mass_data, self.mass83_data]:
-      stats = bdev.DRBD8Status(data[1])
-      self.failUnless(stats.is_in_use)
-      self.failUnless(stats.is_connected and stats.is_secondary and
-                      stats.peer_primary and stats.is_disk_uptodate)
-
-  def testMinor2(self):
-    """Test unconfigured device"""
-    for data in [self.mass_data, self.mass83_data, self.mass80e_data]:
-      stats = bdev.DRBD8Status(data[2])
-      self.failIf(stats.is_in_use)
-
-  def testMinor4(self):
-    """Test WFconn device"""
-    for data in [self.mass_data, self.mass83_data]:
-      stats = bdev.DRBD8Status(data[4])
-      self.failUnless(stats.is_in_use)
-      self.failUnless(stats.is_wfconn and stats.is_primary and
-                      stats.rrole == "Unknown" and
-                      stats.is_disk_uptodate)
-
-  def testMinor6(self):
-    """Test diskless device"""
-    for data in [self.mass_data, self.mass83_data]:
-      stats = bdev.DRBD8Status(data[6])
-      self.failUnless(stats.is_in_use)
-      self.failUnless(stats.is_connected and stats.is_secondary and
-                      stats.peer_primary and stats.is_diskless)
-
-  def testMinor8(self):
-    """Test standalone device"""
-    for data in [self.mass_data, self.mass83_data]:
-      stats = bdev.DRBD8Status(data[8])
-      self.failUnless(stats.is_in_use)
-      self.failUnless(stats.is_standalone and
-                      stats.rrole == "Unknown" and
-                      stats.is_disk_uptodate)
-
-  def testDRBD83SyncFine(self):
-    stats = bdev.DRBD8Status(self.mass83_sync_data[3])
-    self.failUnless(stats.is_in_resync)
-    self.failUnless(stats.sync_percent is not None)
-
-  def testDRBD83SyncBroken(self):
-    stats = bdev.DRBD8Status(self.mass83_sync_krnl_data[3])
-    self.failUnless(stats.is_in_resync)
-    self.failUnless(stats.sync_percent is not None)
-
-
-class TestRADOSBlockDevice(testutils.GanetiTestCase):
-  def setUp(self):
-    """Set up input data"""
-    testutils.GanetiTestCase.setUp(self)
-
-    self.plain_output_old_ok = \
-      testutils.ReadTestData("bdev-rbd/plain_output_old_ok.txt")
-    self.plain_output_old_no_matches = \
-      testutils.ReadTestData("bdev-rbd/plain_output_old_no_matches.txt")
-    self.plain_output_old_extra_matches = \
-      testutils.ReadTestData("bdev-rbd/plain_output_old_extra_matches.txt")
-    self.plain_output_old_empty = \
-      testutils.ReadTestData("bdev-rbd/plain_output_old_empty.txt")
-    self.plain_output_new_ok = \
-      testutils.ReadTestData("bdev-rbd/plain_output_new_ok.txt")
-    self.plain_output_new_no_matches = \
-      testutils.ReadTestData("bdev-rbd/plain_output_new_no_matches.txt")
-    self.plain_output_new_extra_matches = \
-      testutils.ReadTestData("bdev-rbd/plain_output_new_extra_matches.txt")
-    # This file is completely empty, and as such it's not shipped.
-    self.plain_output_new_empty = ""
-    self.json_output_ok = testutils.ReadTestData("bdev-rbd/json_output_ok.txt")
-    self.json_output_no_matches = \
-      testutils.ReadTestData("bdev-rbd/json_output_no_matches.txt")
-    self.json_output_extra_matches = \
-      testutils.ReadTestData("bdev-rbd/json_output_extra_matches.txt")
-    self.json_output_empty = \
-      testutils.ReadTestData("bdev-rbd/json_output_empty.txt")
-    self.output_invalid = testutils.ReadTestData("bdev-rbd/output_invalid.txt")
-
-    self.volume_name = "d7ab910a-4933-4ffe-88d0-faf2ce31390a.rbd.disk0"
-
-  def test_ParseRbdShowmappedJson(self):
-    parse_function = bdev.RADOSBlockDevice._ParseRbdShowmappedJson
-
-    self.assertEqual(parse_function(self.json_output_ok, self.volume_name),
-                     "/dev/rbd3")
-    self.assertEqual(parse_function(self.json_output_empty, self.volume_name),
-                     None)
-    self.assertEqual(parse_function(self.json_output_no_matches,
-                     self.volume_name), None)
-    self.assertRaises(errors.BlockDeviceError, parse_function,
-                      self.json_output_extra_matches, self.volume_name)
-    self.assertRaises(errors.BlockDeviceError, parse_function,
-                      self.output_invalid, self.volume_name)
-
-  def test_ParseRbdShowmappedPlain(self):
-    parse_function = bdev.RADOSBlockDevice._ParseRbdShowmappedPlain
-
-    self.assertEqual(parse_function(self.plain_output_new_ok,
-                     self.volume_name), "/dev/rbd3")
-    self.assertEqual(parse_function(self.plain_output_old_ok,
-                     self.volume_name), "/dev/rbd3")
-    self.assertEqual(parse_function(self.plain_output_new_empty,
-                     self.volume_name), None)
-    self.assertEqual(parse_function(self.plain_output_old_empty,
-                     self.volume_name), None)
-    self.assertEqual(parse_function(self.plain_output_new_no_matches,
-                     self.volume_name), None)
-    self.assertEqual(parse_function(self.plain_output_old_no_matches,
-                     self.volume_name), None)
-    self.assertRaises(errors.BlockDeviceError, parse_function,
-                      self.plain_output_new_extra_matches, self.volume_name)
-    self.assertRaises(errors.BlockDeviceError, parse_function,
-                      self.plain_output_old_extra_matches, self.volume_name)
-    self.assertRaises(errors.BlockDeviceError, parse_function,
-                      self.output_invalid, self.volume_name)
-
-class TestComputeWrongFileStoragePathsInternal(unittest.TestCase):
-  def testPaths(self):
-    paths = bdev._GetForbiddenFileStoragePaths()
-
-    for path in ["/bin", "/usr/local/sbin", "/lib64", "/etc", "/sys"]:
-      self.assertTrue(path in paths)
-
-    self.assertEqual(set(map(os.path.normpath, paths)), paths)
-
-  def test(self):
-    vfsp = bdev._ComputeWrongFileStoragePaths
-    self.assertEqual(vfsp([]), [])
-    self.assertEqual(vfsp(["/tmp"]), [])
-    self.assertEqual(vfsp(["/bin/ls"]), ["/bin/ls"])
-    self.assertEqual(vfsp(["/bin"]), ["/bin"])
-    self.assertEqual(vfsp(["/usr/sbin/vim", "/srv/file-storage"]),
-                     ["/usr/sbin/vim"])
-
-
-class TestComputeWrongFileStoragePaths(testutils.GanetiTestCase):
-  def test(self):
-    tmpfile = self._CreateTempFile()
-
-    utils.WriteFile(tmpfile, data="""
-      /tmp
-      x/y///z/relative
-      # This is a test file
-      /srv/storage
-      /bin
-      /usr/local/lib32/
-      relative/path
-      """)
-
-    self.assertEqual(bdev.ComputeWrongFileStoragePaths(_filename=tmpfile), [
-      "/bin",
-      "/usr/local/lib32",
-      "relative/path",
-      "x/y/z/relative",
-      ])
-
-
-class TestCheckFileStoragePathInternal(unittest.TestCase):
-  def testNonAbsolute(self):
-    for i in ["", "tmp", "foo/bar/baz"]:
-      self.assertRaises(errors.FileStoragePathError,
-                        bdev._CheckFileStoragePath, i, ["/tmp"])
-
-    self.assertRaises(errors.FileStoragePathError,
-                      bdev._CheckFileStoragePath, "/tmp", ["tmp", "xyz"])
-
-  def testNoAllowed(self):
-    self.assertRaises(errors.FileStoragePathError,
-                      bdev._CheckFileStoragePath, "/tmp", [])
-
-  def testNoAdditionalPathComponent(self):
-    self.assertRaises(errors.FileStoragePathError,
-                      bdev._CheckFileStoragePath, "/tmp/foo", ["/tmp/foo"])
-
-  def testAllowed(self):
-    bdev._CheckFileStoragePath("/tmp/foo/a", ["/tmp/foo"])
-    bdev._CheckFileStoragePath("/tmp/foo/a/x", ["/tmp/foo"])
-
-
-class TestCheckFileStoragePath(testutils.GanetiTestCase):
-  def testNonExistantFile(self):
-    filename = "/tmp/this/file/does/not/exist"
-    assert not os.path.exists(filename)
-    self.assertRaises(errors.FileStoragePathError,
-                      bdev.CheckFileStoragePath, "/bin/", _filename=filename)
-    self.assertRaises(errors.FileStoragePathError,
-                      bdev.CheckFileStoragePath, "/srv/file-storage",
-                      _filename=filename)
-
-  def testAllowedPath(self):
-    tmpfile = self._CreateTempFile()
-
-    utils.WriteFile(tmpfile, data="""
-      /srv/storage
-      """)
-
-    bdev.CheckFileStoragePath("/srv/storage/inst1", _filename=tmpfile)
-
-    # No additional path component
-    self.assertRaises(errors.FileStoragePathError,
-                      bdev.CheckFileStoragePath, "/srv/storage",
-                      _filename=tmpfile)
-
-    # Forbidden path
-    self.assertRaises(errors.FileStoragePathError,
-                      bdev.CheckFileStoragePath, "/usr/lib64/xyz",
-                      _filename=tmpfile)
-
-
-class TestLoadAllowedFileStoragePaths(testutils.GanetiTestCase):
-  def testDevNull(self):
-    self.assertEqual(bdev._LoadAllowedFileStoragePaths("/dev/null"), [])
-
-  def testNonExistantFile(self):
-    filename = "/tmp/this/file/does/not/exist"
-    assert not os.path.exists(filename)
-    self.assertEqual(bdev._LoadAllowedFileStoragePaths(filename), [])
-
-  def test(self):
-    tmpfile = self._CreateTempFile()
-
-    utils.WriteFile(tmpfile, data="""
-      # This is a test file
-      /tmp
-      /srv/storage
-      relative/path
-      """)
-
-    self.assertEqual(bdev._LoadAllowedFileStoragePaths(tmpfile), [
-      "/tmp",
-      "/srv/storage",
-      "relative/path",
-      ])
-
-
-class TestExclusiveStoragePvs(unittest.TestCase):
-  """Test cases for functions dealing with LVM PV and exclusive storage"""
-  # Allowance for rounding
-  _EPS = 1e-4
-  _MARGIN = constants.PART_MARGIN + constants.PART_RESERVED + _EPS
-
-  @staticmethod
-  def _GenerateRandomPvInfo(rnd, name, vg):
-    # Granularity is .01 MiB
-    size = rnd.randint(1024 * 100, 10 * 1024 * 1024 * 100)
-    if rnd.choice([False, True]):
-      free = float(rnd.randint(0, size)) / 100.0
-    else:
-      free = float(size) / 100.0
-    size = float(size) / 100.0
-    attr = "a-"
-    return objects.LvmPvInfo(name=name, vg_name=vg, size=size, free=free,
-                             attributes=attr)
-
-  def testGetStdPvSize(self):
-    """Test cases for bdev.LogicalVolume._GetStdPvSize()"""
-    rnd = random.Random(9517)
-    for _ in range(0, 50):
-      # Identical volumes
-      pvi = self._GenerateRandomPvInfo(rnd, "disk", "myvg")
-      onesize = bdev.LogicalVolume._GetStdPvSize([pvi])
-      self.assertTrue(onesize <= pvi.size)
-      self.assertTrue(onesize > pvi.size * (1 - self._MARGIN))
-      for length in range(2, 10):
-        n_size = bdev.LogicalVolume._GetStdPvSize([pvi] * length)
-        self.assertEqual(onesize, n_size)
-
-      # Mixed volumes
-      for length in range(1, 10):
-        pvlist = [self._GenerateRandomPvInfo(rnd, "disk", "myvg")
-                  for _ in range(0, length)]
-        std_size = bdev.LogicalVolume._GetStdPvSize(pvlist)
-        self.assertTrue(compat.all(std_size <= pvi.size for pvi in pvlist))
-        self.assertTrue(compat.any(std_size > pvi.size * (1 - self._MARGIN)
-                                   for pvi in pvlist))
-        pvlist.append(pvlist[0])
-        p1_size = bdev.LogicalVolume._GetStdPvSize(pvlist)
-        self.assertEqual(std_size, p1_size)
-
-  def testComputeNumPvs(self):
-    """Test cases for bdev.LogicalVolume._ComputeNumPvs()"""
-    rnd = random.Random(8067)
-    for _ in range(0, 1000):
-      pvlist = [self._GenerateRandomPvInfo(rnd, "disk", "myvg")]
-      lv_size = float(rnd.randint(10 * 100, 1024 * 1024 * 100)) / 100.0
-      num_pv = bdev.LogicalVolume._ComputeNumPvs(lv_size, pvlist)
-      std_size = bdev.LogicalVolume._GetStdPvSize(pvlist)
-      self.assertTrue(num_pv >= 1)
-      self.assertTrue(num_pv * std_size >= lv_size)
-      self.assertTrue((num_pv - 1) * std_size < lv_size * (1 + self._EPS))
-
-  def testGetEmptyPvNames(self):
-    """Test cases for bdev.LogicalVolume._GetEmptyPvNames()"""
-    rnd = random.Random(21126)
-    for _ in range(0, 100):
-      num_pvs = rnd.randint(1, 20)
-      pvlist = [self._GenerateRandomPvInfo(rnd, "disk%d" % n, "myvg")
-                for n in range(0, num_pvs)]
-      for num_req in range(1, num_pvs + 2):
-        epvs = bdev.LogicalVolume._GetEmptyPvNames(pvlist, num_req)
-        epvs_set = compat.UniqueFrozenset(epvs)
-        if len(epvs) > 1:
-          self.assertEqual(len(epvs), len(epvs_set))
-        for pvi in pvlist:
-          if pvi.name in epvs_set:
-            self.assertEqual(pvi.size, pvi.free)
-          else:
-            # There should be no remaining empty PV when less than the
-            # requeste number of PVs has been returned
-            self.assertTrue(len(epvs) == num_req or pvi.free != pvi.size)
-
-
-if __name__ == "__main__":
-  testutils.GanetiTestProgram()
diff --git a/test/py/ganeti.block.bdev_unittest.py b/test/py/ganeti.block.bdev_unittest.py
new file mode 100755
index 0000000..1610582
--- /dev/null
+++ b/test/py/ganeti.block.bdev_unittest.py
@@ -0,0 +1,613 @@
+#!/usr/bin/python
+#
+
+# Copyright (C) 2006, 2007, 2010, 2012, 2013 Google Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.
+
+
+"""Script for unittesting the bdev module"""
+
+
+import os
+import random
+import unittest
+
+from ganeti import compat
+from ganeti import constants
+from ganeti import errors
+from ganeti import objects
+from ganeti import utils
+from ganeti.block import bdev
+
+import testutils
+
+
+class TestBaseDRBD(testutils.GanetiTestCase):
+  def testGetVersion(self):
+    data = [
+      ["version: 8.0.12 (api:76/proto:86-91)"],
+      ["version: 8.2.7 (api:88/proto:0-100)"],
+      ["version: 8.3.7.49 (api:188/proto:13-191)"],
+    ]
+    result = [
+      {
+      "k_major": 8,
+      "k_minor": 0,
+      "k_point": 12,
+      "api": 76,
+      "proto": 86,
+      "proto2": "91",
+      },
+      {
+      "k_major": 8,
+      "k_minor": 2,
+      "k_point": 7,
+      "api": 88,
+      "proto": 0,
+      "proto2": "100",
+      },
+      {
+      "k_major": 8,
+      "k_minor": 3,
+      "k_point": 7,
+      "api": 188,
+      "proto": 13,
+      "proto2": "191",
+      }
+    ]
+    for d,r in zip(data, result):
+      self.assertEqual(bdev.BaseDRBD._GetVersion(d), r)
+
+
+class TestDRBD8Runner(testutils.GanetiTestCase):
+  """Testing case for DRBD8"""
+
+  @staticmethod
+  def _has_disk(data, dname, mname):
+    """Check local disk corectness"""
+    retval = (
+      "local_dev" in data and
+      data["local_dev"] == dname and
+      "meta_dev" in data and
+      data["meta_dev"] == mname and
+      "meta_index" in data and
+      data["meta_index"] == 0
+      )
+    return retval
+
+  @staticmethod
+  def _has_net(data, local, remote):
+    """Check network connection parameters"""
+    retval = (
+      "local_addr" in data and
+      data["local_addr"] == local and
+      "remote_addr" in data and
+      data["remote_addr"] == remote
+      )
+    return retval
+
+  def testParserCreation(self):
+    """Test drbdsetup show parser creation"""
+    bdev.DRBD8._GetShowParser()
+
+  def testParser80(self):
+    """Test drbdsetup show parser for disk and network version 8.0"""
+    data = testutils.ReadTestData("bdev-drbd-8.0.txt")
+    result = bdev.DRBD8._GetDevInfo(data)
+    self.failUnless(self._has_disk(result, "/dev/xenvg/test.data",
+                                   "/dev/xenvg/test.meta"),
+                    "Wrong local disk info")
+    self.failUnless(self._has_net(result, ("192.0.2.1", 11000),
+                                  ("192.0.2.2", 11000)),
+                    "Wrong network info (8.0.x)")
+
+  def testParser83(self):
+    """Test drbdsetup show parser for disk and network version 8.3"""
+    data = testutils.ReadTestData("bdev-drbd-8.3.txt")
+    result = bdev.DRBD8._GetDevInfo(data)
+    self.failUnless(self._has_disk(result, "/dev/xenvg/test.data",
+                                   "/dev/xenvg/test.meta"),
+                    "Wrong local disk info")
+    self.failUnless(self._has_net(result, ("192.0.2.1", 11000),
+                                  ("192.0.2.2", 11000)),
+                    "Wrong network info (8.0.x)")
+
+  def testParserNetIP4(self):
+    """Test drbdsetup show parser for IPv4 network"""
+    data = testutils.ReadTestData("bdev-drbd-net-ip4.txt")
+    result = bdev.DRBD8._GetDevInfo(data)
+    self.failUnless(("local_dev" not in result and
+                     "meta_dev" not in result and
+                     "meta_index" not in result),
+                    "Should not find local disk info")
+    self.failUnless(self._has_net(result, ("192.0.2.1", 11002),
+                                  ("192.0.2.2", 11002)),
+                    "Wrong network info (IPv4)")
+
+  def testParserNetIP6(self):
+    """Test drbdsetup show parser for IPv6 network"""
+    data = testutils.ReadTestData("bdev-drbd-net-ip6.txt")
+    result = bdev.DRBD8._GetDevInfo(data)
+    self.failUnless(("local_dev" not in result and
+                     "meta_dev" not in result and
+                     "meta_index" not in result),
+                    "Should not find local disk info")
+    self.failUnless(self._has_net(result, ("2001:db8:65::1", 11048),
+                                  ("2001:db8:66::1", 11048)),
+                    "Wrong network info (IPv6)")
+
+  def testParserDisk(self):
+    """Test drbdsetup show parser for disk"""
+    data = testutils.ReadTestData("bdev-drbd-disk.txt")
+    result = bdev.DRBD8._GetDevInfo(data)
+    self.failUnless(self._has_disk(result, "/dev/xenvg/test.data",
+                                   "/dev/xenvg/test.meta"),
+                    "Wrong local disk info")
+    self.failUnless(("local_addr" not in result and
+                     "remote_addr" not in result),
+                    "Should not find network info")
+
+  def testBarriersOptions(self):
+    """Test class method that generates drbdsetup options for disk barriers"""
+    # Tests that should fail because of wrong version/options combinations
+    should_fail = [
+      (8, 0, 12, "bfd", True),
+      (8, 0, 12, "fd", False),
+      (8, 0, 12, "b", True),
+      (8, 2, 7, "bfd", True),
+      (8, 2, 7, "b", True)
+    ]
+
+    for vmaj, vmin, vrel, opts, meta in should_fail:
+      self.assertRaises(errors.BlockDeviceError,
+                        bdev.DRBD8._ComputeDiskBarrierArgs,
+                        vmaj, vmin, vrel, opts, meta)
+
+    # get the valid options from the frozenset(frozenset()) in constants.
+    valid_options = [list(x)[0] for x in constants.DRBD_VALID_BARRIER_OPT]
+
+    # Versions that do not support anything
+    for vmaj, vmin, vrel in ((8, 0, 0), (8, 0, 11), (8, 2, 6)):
+      for opts in valid_options:
+        self.assertRaises(errors.BlockDeviceError,
+                          bdev.DRBD8._ComputeDiskBarrierArgs,
+                          vmaj, vmin, vrel, opts, True)
+
+    # Versions with partial support (testing only options that are supported)
+    tests = [
+      (8, 0, 12, "n", False, []),
+      (8, 0, 12, "n", True, ["--no-md-flushes"]),
+      (8, 2, 7, "n", False, []),
+      (8, 2, 7, "fd", False, ["--no-disk-flushes", "--no-disk-drain"]),
+      (8, 0, 12, "n", True, ["--no-md-flushes"]),
+      ]
+
+    # Versions that support everything
+    for vmaj, vmin, vrel in ((8, 3, 0), (8, 3, 12)):
+      tests.append((vmaj, vmin, vrel, "bfd", True,
+                    ["--no-disk-barrier", "--no-disk-drain",
+                     "--no-disk-flushes", "--no-md-flushes"]))
+      tests.append((vmaj, vmin, vrel, "n", False, []))
+      tests.append((vmaj, vmin, vrel, "b", True,
+                    ["--no-disk-barrier", "--no-md-flushes"]))
+      tests.append((vmaj, vmin, vrel, "fd", False,
+                    ["--no-disk-flushes", "--no-disk-drain"]))
+      tests.append((vmaj, vmin, vrel, "n", True, ["--no-md-flushes"]))
+
+    # Test execution
+    for test in tests:
+      vmaj, vmin, vrel, disabled_barriers, disable_meta_flush, expected = test
+      args = \
+        bdev.DRBD8._ComputeDiskBarrierArgs(vmaj, vmin, vrel,
+                                           disabled_barriers,
+                                           disable_meta_flush)
+      self.failUnless(set(args) == set(expected),
+                      "For test %s, got wrong results %s" % (test, args))
+
+    # Unsupported or invalid versions
+    for vmaj, vmin, vrel in ((0, 7, 25), (9, 0, 0), (7, 0, 0), (8, 4, 0)):
+      self.assertRaises(errors.BlockDeviceError,
+                        bdev.DRBD8._ComputeDiskBarrierArgs,
+                        vmaj, vmin, vrel, "n", True)
+
+    # Invalid options
+    for option in ("", "c", "whatever", "nbdfc", "nf"):
+      self.assertRaises(errors.BlockDeviceError,
+                        bdev.DRBD8._ComputeDiskBarrierArgs,
+                        8, 3, 11, option, True)
+
+
+class TestDRBD8Status(testutils.GanetiTestCase):
+  """Testing case for DRBD8 /proc status"""
+
+  def setUp(self):
+    """Read in txt data"""
+    testutils.GanetiTestCase.setUp(self)
+    proc_data = testutils.TestDataFilename("proc_drbd8.txt")
+    proc80e_data = testutils.TestDataFilename("proc_drbd80-emptyline.txt")
+    proc83_data = testutils.TestDataFilename("proc_drbd83.txt")
+    proc83_sync_data = testutils.TestDataFilename("proc_drbd83_sync.txt")
+    proc83_sync_krnl_data = \
+      testutils.TestDataFilename("proc_drbd83_sync_krnl2.6.39.txt")
+    self.proc_data = bdev.DRBD8._GetProcData(filename=proc_data)
+    self.proc80e_data = bdev.DRBD8._GetProcData(filename=proc80e_data)
+    self.proc83_data = bdev.DRBD8._GetProcData(filename=proc83_data)
+    self.proc83_sync_data = bdev.DRBD8._GetProcData(filename=proc83_sync_data)
+    self.proc83_sync_krnl_data = \
+      bdev.DRBD8._GetProcData(filename=proc83_sync_krnl_data)
+    self.mass_data = bdev.DRBD8._MassageProcData(self.proc_data)
+    self.mass80e_data = bdev.DRBD8._MassageProcData(self.proc80e_data)
+    self.mass83_data = bdev.DRBD8._MassageProcData(self.proc83_data)
+    self.mass83_sync_data = bdev.DRBD8._MassageProcData(self.proc83_sync_data)
+    self.mass83_sync_krnl_data = \
+      bdev.DRBD8._MassageProcData(self.proc83_sync_krnl_data)
+
+  def testIOErrors(self):
+    """Test handling of errors while reading the proc file."""
+    temp_file = self._CreateTempFile()
+    os.unlink(temp_file)
+    self.failUnlessRaises(errors.BlockDeviceError,
+                          bdev.DRBD8._GetProcData, filename=temp_file)
+
+  def testHelper(self):
+    """Test reading usermode_helper in /sys."""
+    sys_drbd_helper = testutils.TestDataFilename("sys_drbd_usermode_helper.txt")
+    drbd_helper = bdev.DRBD8.GetUsermodeHelper(filename=sys_drbd_helper)
+    self.failUnlessEqual(drbd_helper, "/bin/true")
+
+  def testHelperIOErrors(self):
+    """Test handling of errors while reading usermode_helper in /sys."""
+    temp_file = self._CreateTempFile()
+    os.unlink(temp_file)
+    self.failUnlessRaises(errors.BlockDeviceError,
+                          bdev.DRBD8.GetUsermodeHelper, filename=temp_file)
+
+  def testMinorNotFound(self):
+    """Test not-found-minor in /proc"""
+    self.failUnless(9 not in self.mass_data)
+    self.failUnless(9 not in self.mass83_data)
+    self.failUnless(3 not in self.mass80e_data)
+
+  def testLineNotMatch(self):
+    """Test wrong line passed to DRBD8Status"""
+    self.assertRaises(errors.BlockDeviceError, bdev.DRBD8Status, "foo")
+
+  def testMinor0(self):
+    """Test connected, primary device"""
+    for data in [self.mass_data, self.mass83_data]:
+      stats = bdev.DRBD8Status(data[0])
+      self.failUnless(stats.is_in_use)
+      self.failUnless(stats.is_connected and stats.is_primary and
+                      stats.peer_secondary and stats.is_disk_uptodate)
+
+  def testMinor1(self):
+    """Test connected, secondary device"""
+    for data in [self.mass_data, self.mass83_data]:
+      stats = bdev.DRBD8Status(data[1])
+      self.failUnless(stats.is_in_use)
+      self.failUnless(stats.is_connected and stats.is_secondary and
+                      stats.peer_primary and stats.is_disk_uptodate)
+
+  def testMinor2(self):
+    """Test unconfigured device"""
+    for data in [self.mass_data, self.mass83_data, self.mass80e_data]:
+      stats = bdev.DRBD8Status(data[2])
+      self.failIf(stats.is_in_use)
+
+  def testMinor4(self):
+    """Test WFconn device"""
+    for data in [self.mass_data, self.mass83_data]:
+      stats = bdev.DRBD8Status(data[4])
+      self.failUnless(stats.is_in_use)
+      self.failUnless(stats.is_wfconn and stats.is_primary and
+                      stats.rrole == "Unknown" and
+                      stats.is_disk_uptodate)
+
+  def testMinor6(self):
+    """Test diskless device"""
+    for data in [self.mass_data, self.mass83_data]:
+      stats = bdev.DRBD8Status(data[6])
+      self.failUnless(stats.is_in_use)
+      self.failUnless(stats.is_connected and stats.is_secondary and
+                      stats.peer_primary and stats.is_diskless)
+
+  def testMinor8(self):
+    """Test standalone device"""
+    for data in [self.mass_data, self.mass83_data]:
+      stats = bdev.DRBD8Status(data[8])
+      self.failUnless(stats.is_in_use)
+      self.failUnless(stats.is_standalone and
+                      stats.rrole == "Unknown" and
+                      stats.is_disk_uptodate)
+
+  def testDRBD83SyncFine(self):
+    stats = bdev.DRBD8Status(self.mass83_sync_data[3])
+    self.failUnless(stats.is_in_resync)
+    self.failUnless(stats.sync_percent is not None)
+
+  def testDRBD83SyncBroken(self):
+    stats = bdev.DRBD8Status(self.mass83_sync_krnl_data[3])
+    self.failUnless(stats.is_in_resync)
+    self.failUnless(stats.sync_percent is not None)
+
+
+class TestRADOSBlockDevice(testutils.GanetiTestCase):
+  def setUp(self):
+    """Set up input data"""
+    testutils.GanetiTestCase.setUp(self)
+
+    self.plain_output_old_ok = \
+      testutils.ReadTestData("bdev-rbd/plain_output_old_ok.txt")
+    self.plain_output_old_no_matches = \
+      testutils.ReadTestData("bdev-rbd/plain_output_old_no_matches.txt")
+    self.plain_output_old_extra_matches = \
+      testutils.ReadTestData("bdev-rbd/plain_output_old_extra_matches.txt")
+    self.plain_output_old_empty = \
+      testutils.ReadTestData("bdev-rbd/plain_output_old_empty.txt")
+    self.plain_output_new_ok = \
+      testutils.ReadTestData("bdev-rbd/plain_output_new_ok.txt")
+    self.plain_output_new_no_matches = \
+      testutils.ReadTestData("bdev-rbd/plain_output_new_no_matches.txt")
+    self.plain_output_new_extra_matches = \
+      testutils.ReadTestData("bdev-rbd/plain_output_new_extra_matches.txt")
+    # This file is completely empty, and as such it's not shipped.
+    self.plain_output_new_empty = ""
+    self.json_output_ok = testutils.ReadTestData("bdev-rbd/json_output_ok.txt")
+    self.json_output_no_matches = \
+      testutils.ReadTestData("bdev-rbd/json_output_no_matches.txt")
+    self.json_output_extra_matches = \
+      testutils.ReadTestData("bdev-rbd/json_output_extra_matches.txt")
+    self.json_output_empty = \
+      testutils.ReadTestData("bdev-rbd/json_output_empty.txt")
+    self.output_invalid = testutils.ReadTestData("bdev-rbd/output_invalid.txt")
+
+    self.volume_name = "d7ab910a-4933-4ffe-88d0-faf2ce31390a.rbd.disk0"
+
+  def test_ParseRbdShowmappedJson(self):
+    parse_function = bdev.RADOSBlockDevice._ParseRbdShowmappedJson
+
+    self.assertEqual(parse_function(self.json_output_ok, self.volume_name),
+                     "/dev/rbd3")
+    self.assertEqual(parse_function(self.json_output_empty, self.volume_name),
+                     None)
+    self.assertEqual(parse_function(self.json_output_no_matches,
+                     self.volume_name), None)
+    self.assertRaises(errors.BlockDeviceError, parse_function,
+                      self.json_output_extra_matches, self.volume_name)
+    self.assertRaises(errors.BlockDeviceError, parse_function,
+                      self.output_invalid, self.volume_name)
+
+  def test_ParseRbdShowmappedPlain(self):
+    parse_function = bdev.RADOSBlockDevice._ParseRbdShowmappedPlain
+
+    self.assertEqual(parse_function(self.plain_output_new_ok,
+                     self.volume_name), "/dev/rbd3")
+    self.assertEqual(parse_function(self.plain_output_old_ok,
+                     self.volume_name), "/dev/rbd3")
+    self.assertEqual(parse_function(self.plain_output_new_empty,
+                     self.volume_name), None)
+    self.assertEqual(parse_function(self.plain_output_old_empty,
+                     self.volume_name), None)
+    self.assertEqual(parse_function(self.plain_output_new_no_matches,
+                     self.volume_name), None)
+    self.assertEqual(parse_function(self.plain_output_old_no_matches,
+                     self.volume_name), None)
+    self.assertRaises(errors.BlockDeviceError, parse_function,
+                      self.plain_output_new_extra_matches, self.volume_name)
+    self.assertRaises(errors.BlockDeviceError, parse_function,
+                      self.plain_output_old_extra_matches, self.volume_name)
+    self.assertRaises(errors.BlockDeviceError, parse_function,
+                      self.output_invalid, self.volume_name)
+
+class TestComputeWrongFileStoragePathsInternal(unittest.TestCase):
+  def testPaths(self):
+    paths = bdev._GetForbiddenFileStoragePaths()
+
+    for path in ["/bin", "/usr/local/sbin", "/lib64", "/etc", "/sys"]:
+      self.assertTrue(path in paths)
+
+    self.assertEqual(set(map(os.path.normpath, paths)), paths)
+
+  def test(self):
+    vfsp = bdev._ComputeWrongFileStoragePaths
+    self.assertEqual(vfsp([]), [])
+    self.assertEqual(vfsp(["/tmp"]), [])
+    self.assertEqual(vfsp(["/bin/ls"]), ["/bin/ls"])
+    self.assertEqual(vfsp(["/bin"]), ["/bin"])
+    self.assertEqual(vfsp(["/usr/sbin/vim", "/srv/file-storage"]),
+                     ["/usr/sbin/vim"])
+
+
+class TestComputeWrongFileStoragePaths(testutils.GanetiTestCase):
+  def test(self):
+    tmpfile = self._CreateTempFile()
+
+    utils.WriteFile(tmpfile, data="""
+      /tmp
+      x/y///z/relative
+      # This is a test file
+      /srv/storage
+      /bin
+      /usr/local/lib32/
+      relative/path
+      """)
+
+    self.assertEqual(bdev.ComputeWrongFileStoragePaths(_filename=tmpfile), [
+      "/bin",
+      "/usr/local/lib32",
+      "relative/path",
+      "x/y/z/relative",
+      ])
+
+
+class TestCheckFileStoragePathInternal(unittest.TestCase):
+  def testNonAbsolute(self):
+    for i in ["", "tmp", "foo/bar/baz"]:
+      self.assertRaises(errors.FileStoragePathError,
+                        bdev._CheckFileStoragePath, i, ["/tmp"])
+
+    self.assertRaises(errors.FileStoragePathError,
+                      bdev._CheckFileStoragePath, "/tmp", ["tmp", "xyz"])
+
+  def testNoAllowed(self):
+    self.assertRaises(errors.FileStoragePathError,
+                      bdev._CheckFileStoragePath, "/tmp", [])
+
+  def testNoAdditionalPathComponent(self):
+    self.assertRaises(errors.FileStoragePathError,
+                      bdev._CheckFileStoragePath, "/tmp/foo", ["/tmp/foo"])
+
+  def testAllowed(self):
+    bdev._CheckFileStoragePath("/tmp/foo/a", ["/tmp/foo"])
+    bdev._CheckFileStoragePath("/tmp/foo/a/x", ["/tmp/foo"])
+
+
+class TestCheckFileStoragePath(testutils.GanetiTestCase):
+  def testNonExistantFile(self):
+    filename = "/tmp/this/file/does/not/exist"
+    assert not os.path.exists(filename)
+    self.assertRaises(errors.FileStoragePathError,
+                      bdev.CheckFileStoragePath, "/bin/", _filename=filename)
+    self.assertRaises(errors.FileStoragePathError,
+                      bdev.CheckFileStoragePath, "/srv/file-storage",
+                      _filename=filename)
+
+  def testAllowedPath(self):
+    tmpfile = self._CreateTempFile()
+
+    utils.WriteFile(tmpfile, data="""
+      /srv/storage
+      """)
+
+    bdev.CheckFileStoragePath("/srv/storage/inst1", _filename=tmpfile)
+
+    # No additional path component
+    self.assertRaises(errors.FileStoragePathError,
+                      bdev.CheckFileStoragePath, "/srv/storage",
+                      _filename=tmpfile)
+
+    # Forbidden path
+    self.assertRaises(errors.FileStoragePathError,
+                      bdev.CheckFileStoragePath, "/usr/lib64/xyz",
+                      _filename=tmpfile)
+
+
+class TestLoadAllowedFileStoragePaths(testutils.GanetiTestCase):
+  def testDevNull(self):
+    self.assertEqual(bdev._LoadAllowedFileStoragePaths("/dev/null"), [])
+
+  def testNonExistantFile(self):
+    filename = "/tmp/this/file/does/not/exist"
+    assert not os.path.exists(filename)
+    self.assertEqual(bdev._LoadAllowedFileStoragePaths(filename), [])
+
+  def test(self):
+    tmpfile = self._CreateTempFile()
+
+    utils.WriteFile(tmpfile, data="""
+      # This is a test file
+      /tmp
+      /srv/storage
+      relative/path
+      """)
+
+    self.assertEqual(bdev._LoadAllowedFileStoragePaths(tmpfile), [
+      "/tmp",
+      "/srv/storage",
+      "relative/path",
+      ])
+
+
+class TestExclusiveStoragePvs(unittest.TestCase):
+  """Test cases for functions dealing with LVM PV and exclusive storage"""
+  # Allowance for rounding
+  _EPS = 1e-4
+  _MARGIN = constants.PART_MARGIN + constants.PART_RESERVED + _EPS
+
+  @staticmethod
+  def _GenerateRandomPvInfo(rnd, name, vg):
+    # Granularity is .01 MiB
+    size = rnd.randint(1024 * 100, 10 * 1024 * 1024 * 100)
+    if rnd.choice([False, True]):
+      free = float(rnd.randint(0, size)) / 100.0
+    else:
+      free = float(size) / 100.0
+    size = float(size) / 100.0
+    attr = "a-"
+    return objects.LvmPvInfo(name=name, vg_name=vg, size=size, free=free,
+                             attributes=attr)
+
+  def testGetStdPvSize(self):
+    """Test cases for bdev.LogicalVolume._GetStdPvSize()"""
+    rnd = random.Random(9517)
+    for _ in range(0, 50):
+      # Identical volumes
+      pvi = self._GenerateRandomPvInfo(rnd, "disk", "myvg")
+      onesize = bdev.LogicalVolume._GetStdPvSize([pvi])
+      self.assertTrue(onesize <= pvi.size)
+      self.assertTrue(onesize > pvi.size * (1 - self._MARGIN))
+      for length in range(2, 10):
+        n_size = bdev.LogicalVolume._GetStdPvSize([pvi] * length)
+        self.assertEqual(onesize, n_size)
+
+      # Mixed volumes
+      for length in range(1, 10):
+        pvlist = [self._GenerateRandomPvInfo(rnd, "disk", "myvg")
+                  for _ in range(0, length)]
+        std_size = bdev.LogicalVolume._GetStdPvSize(pvlist)
+        self.assertTrue(compat.all(std_size <= pvi.size for pvi in pvlist))
+        self.assertTrue(compat.any(std_size > pvi.size * (1 - self._MARGIN)
+                                   for pvi in pvlist))
+        pvlist.append(pvlist[0])
+        p1_size = bdev.LogicalVolume._GetStdPvSize(pvlist)
+        self.assertEqual(std_size, p1_size)
+
+  def testComputeNumPvs(self):
+    """Test cases for bdev.LogicalVolume._ComputeNumPvs()"""
+    rnd = random.Random(8067)
+    for _ in range(0, 1000):
+      pvlist = [self._GenerateRandomPvInfo(rnd, "disk", "myvg")]
+      lv_size = float(rnd.randint(10 * 100, 1024 * 1024 * 100)) / 100.0
+      num_pv = bdev.LogicalVolume._ComputeNumPvs(lv_size, pvlist)
+      std_size = bdev.LogicalVolume._GetStdPvSize(pvlist)
+      self.assertTrue(num_pv >= 1)
+      self.assertTrue(num_pv * std_size >= lv_size)
+      self.assertTrue((num_pv - 1) * std_size < lv_size * (1 + self._EPS))
+
+  def testGetEmptyPvNames(self):
+    """Test cases for bdev.LogicalVolume._GetEmptyPvNames()"""
+    rnd = random.Random(21126)
+    for _ in range(0, 100):
+      num_pvs = rnd.randint(1, 20)
+      pvlist = [self._GenerateRandomPvInfo(rnd, "disk%d" % n, "myvg")
+                for n in range(0, num_pvs)]
+      for num_req in range(1, num_pvs + 2):
+        epvs = bdev.LogicalVolume._GetEmptyPvNames(pvlist, num_req)
+        epvs_set = compat.UniqueFrozenset(epvs)
+        if len(epvs) > 1:
+          self.assertEqual(len(epvs), len(epvs_set))
+        for pvi in pvlist:
+          if pvi.name in epvs_set:
+            self.assertEqual(pvi.size, pvi.free)
+          else:
+            # There should be no remaining empty PV when less than the
+            # requeste number of PVs has been returned
+            self.assertTrue(len(epvs) == num_req or pvi.free != pvi.size)
+
+
+if __name__ == "__main__":
+  testutils.GanetiTestProgram()
