Synnefo » snf-ganeti

blockdir = $(pkgpythondir)/block

	lib/block \

block_PYTHON = \

	lib/block/__init__.py \

	lib/block/bdev.py \

	lib/block/base.py \

	lib/block/drbd.py \

	lib/block/drbd_info.py \

	lib/block/drbd_cmdgen.py

	test/py/ganeti.block.bdev_unittest.py \

	test/py/ganeti.block.drbd_unittest.py \

	$(block_PYTHON) \

from ganeti.block import bdev

from ganeti.block import drbd

from ganeti.block.base import BlockDev

from ganeti.block.drbd import DRBD8

#

#

# 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

"""

#

#

# 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 - base class and utility functions"""

import logging

from ganeti import objects

from ganeti import constants

from ganeti import utils

from ganeti import errors

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.

    @type force: boolean

    """

    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.

    @type pause: boolean

    @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))

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 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

#

#

# 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 errno

import stat

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 pathutils

from ganeti import serializer

from ganeti.block import drbd

from ganeti.block import base

class RbdShowmappedJsonError(Exception):

  """`rbd showmmapped' JSON formatting error Exception class.

  """

  pass

def _CheckResult(result):

  """Throws an error if the given result is a failed one.

  @param result: result from RunCmd

  """

  if result.failed:

    base.ThrowError("Command: %s error: %s - %s",

                    result.cmd, result.fail_reason, result.output)

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 LogicalVolume(base.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

      base.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):

      base.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:

        base.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:

        base.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:

      base.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)):

      base.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:

      base.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:

      base.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=k", "--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:

      base.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)

    base.IgnoreError(snap.Remove)

    vg_info = self.GetVGInfo([self._vg_name], False)

    if not vg_info:

      base.ThrowError("Can't compute VG info for vg %s", self._vg_name)

    free_size, _, _ = vg_info[0]

    if free_size < size:

      base.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.

    """

    base.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():

        base.ThrowError("Can't attach to LV during Grow()")

    full_stripe_size = self.pe_size * self.stripe_count

    # pe_size is in KB

    amount *= 1024

    rest = amount % full_stripe_size

    if rest != 0:

      amount += full_stripe_size - rest

    cmd = ["lvextend", "-L", "+%dk" % 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

    base.ThrowError("Can't grow LV %s: %s", self.dev_path, result.output)

class FileStorage(base.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):

      base.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:

        base.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

    base.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:

      base.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:

      base.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:

        base.ThrowError("File already existing: %s", dev_path)

      base.ThrowError("Error in file creation: %", str(err))

    return FileStorage(unique_id, children, size, params)

class PersistentBlockDevice(base.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.

    """

    base.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.

    """

    base.ThrowError("Grow is not supported for PersistentBlockDev storage")

class RADOSBlockDevice(base.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