cinder/cinder/brick/initiator/linuxscsi.py

194 lines
7.1 KiB
Python

# (c) Copyright 2013 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""Generic linux scsi subsystem and Multipath utilities.
Note, this is not iSCSI.
"""
import os
import re
from oslo.concurrency import processutils as putils
from cinder.brick import executor
from cinder.i18n import _, _LW
from cinder.openstack.common import log as logging
LOG = logging.getLogger(__name__)
MULTIPATH_ERROR_REGEX = re.compile("\w{3} \d+ \d\d:\d\d:\d\d \|.*$")
class LinuxSCSI(executor.Executor):
def __init__(self, root_helper, execute=putils.execute,
*args, **kwargs):
super(LinuxSCSI, self).__init__(root_helper, execute,
*args, **kwargs)
def echo_scsi_command(self, path, content):
"""Used to echo strings to scsi subsystem."""
args = ["-a", path]
kwargs = dict(process_input=content,
run_as_root=True,
root_helper=self._root_helper)
self._execute('tee', *args, **kwargs)
def get_name_from_path(self, path):
"""Translates /dev/disk/by-path/ entry to /dev/sdX."""
name = os.path.realpath(path)
if name.startswith("/dev/"):
return name
else:
return None
def remove_scsi_device(self, device):
"""Removes a scsi device based upon /dev/sdX name."""
path = "/sys/block/%s/device/delete" % device.replace("/dev/", "")
if os.path.exists(path):
# flush any outstanding IO first
self.flush_device_io(device)
LOG.debug("Remove SCSI device(%s) with %s" % (device, path))
self.echo_scsi_command(path, "1")
def get_device_info(self, device):
(out, _err) = self._execute('sg_scan', device, run_as_root=True,
root_helper=self._root_helper)
dev_info = {'device': device, 'host': None,
'channel': None, 'id': None, 'lun': None}
if out:
line = out.strip()
line = line.replace(device + ": ", "")
info = line.split(" ")
for item in info:
if '=' in item:
pair = item.split('=')
dev_info[pair[0]] = pair[1]
elif 'scsi' in item:
dev_info['host'] = item.replace('scsi', '')
return dev_info
def remove_multipath_device(self, multipath_name):
"""This removes LUNs associated with a multipath device
and the multipath device itself.
"""
LOG.debug("remove multipath device %s" % multipath_name)
mpath_dev = self.find_multipath_device(multipath_name)
if mpath_dev:
devices = mpath_dev['devices']
LOG.debug("multipath LUNs to remove %s" % devices)
for device in devices:
self.remove_scsi_device(device['device'])
self.flush_multipath_device(mpath_dev['id'])
def flush_device_io(self, device):
"""This is used to flush any remaining IO in the buffers."""
try:
LOG.debug("Flushing IO for device %s" % device)
self._execute('blockdev', '--flushbufs', device, run_as_root=True,
root_helper=self._root_helper)
except putils.ProcessExecutionError as exc:
msg = _("Failed to flush IO buffers prior to removing"
" device: (%(code)s)") % {'code': exc.exit_code}
LOG.warn(msg)
def flush_multipath_device(self, device):
try:
LOG.debug("Flush multipath device %s" % device)
self._execute('multipath', '-f', device, run_as_root=True,
root_helper=self._root_helper)
except putils.ProcessExecutionError as exc:
LOG.warn(_LW("multipath call failed exit (%(code)s)")
% {'code': exc.exit_code})
def flush_multipath_devices(self):
try:
self._execute('multipath', '-F', run_as_root=True,
root_helper=self._root_helper)
except putils.ProcessExecutionError as exc:
LOG.warn(_LW("multipath call failed exit (%(code)s)")
% {'code': exc.exit_code})
def find_multipath_device(self, device):
"""Find a multipath device associated with a LUN device name.
device can be either a /dev/sdX entry or a multipath id.
"""
mdev = None
devices = []
out = None
try:
(out, _err) = self._execute('multipath', '-l', device,
run_as_root=True,
root_helper=self._root_helper)
except putils.ProcessExecutionError as exc:
LOG.warn(_LW("multipath call failed exit (%(code)s)")
% {'code': exc.exit_code})
return None
if out:
lines = out.strip()
lines = lines.split("\n")
lines = [line for line in lines
if not re.match(MULTIPATH_ERROR_REGEX, line)]
if lines:
line = lines[0]
info = line.split(" ")
# device line output is different depending
# on /etc/multipath.conf settings.
if info[1][:2] == "dm":
mdev = "/dev/%s" % info[1]
mdev_id = info[0]
elif info[2][:2] == "dm":
mdev = "/dev/%s" % info[2]
mdev_id = info[1].replace('(', '')
mdev_id = mdev_id.replace(')', '')
if mdev is None:
LOG.warn(_LW("Couldn't find multipath device %(line)s")
% {'line': line})
return None
LOG.debug("Found multipath device = %(mdev)s"
% {'mdev': mdev})
device_lines = lines[3:]
for dev_line in device_lines:
if dev_line.find("policy") != -1:
continue
dev_line = dev_line.lstrip(' |-`')
dev_info = dev_line.split()
address = dev_info[0].split(":")
dev = {'device': '/dev/%s' % dev_info[1],
'host': address[0], 'channel': address[1],
'id': address[2], 'lun': address[3]
}
devices.append(dev)
if mdev is not None:
info = {"device": mdev,
"id": mdev_id,
"devices": devices}
return info
return None