openstack/os-brick
Code Issues Proposed changes
os-brick/os_brick/initiator/linuxscsi.py
Rajat Dhasmana 1435059da5 Check paths before extending device 
In a multipath enabled deployment, when we try to extend a volume
and some paths are down, we fail to extend the multipath device and
leave the environment in an inconsistent state. See LP Bug #2032177
for more details.

To handle this, we check if all the paths are up before trying to
extend the device and fail fast if any path is down. This ensures
we don't partially extend some paths and leave the other to the
original size leading to inconsistent state in the environment.

Closes-Bug: 2032177

Change-Id: I5fc02efc5e9657821a1335f1c1ac5fe036e9329a
2023-08-24 11:40:32 +00:00

856 lines
35 KiB
Python
Raw Blame History

# (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.
"""
from __future__ import annotations
import glob
import os
import re
import time
from typing import Optional
from oslo_concurrency import processutils as putils
from oslo_log import log as logging
from oslo_utils import excutils
from os_brick import constants
from os_brick import exception
from os_brick import executor
from os_brick.privileged import rootwrap as priv_rootwrap
from os_brick import utils
LOG = logging.getLogger(__name__)
MULTIPATH_ERROR_REGEX = re.compile(r"\w{3} \d+ \d\d:\d\d:\d\d \|.*$")
MULTIPATH_WWID_REGEX = re.compile(r"\((?P<wwid>.+)\)")
MULTIPATH_DEVICE_ACTIONS = ['unchanged:', 'reject:', 'reload:',
'switchpg:', 'rename:', 'create:',
'resize:']
MULTIPATHD_RESIZE_TIMEOUT = 120
class LinuxSCSI(executor.Executor):
# As found in drivers/scsi/scsi_lib.c
WWN_TYPES = {'t10.': '1', 'eui.': '2', 'naa.': '3'}
@staticmethod
def lun_for_addressing(lun, addressing_mode=None):
"""Convert luns to values used by the system.
How a LUN is codified depends on the standard being used by the storage
array and the mode, which is unknown by the host.
Addressing modes based on the standard:
* SAM:
- 64bit address
* SAM-2:
- Peripheral device addressing method (Code 00b)
+ Single level
+ Multi level
- Flat space addressing method (Code 01b)
- Logical unit addressing mode (Code 10b)
- Extended logical unit addressing method (Code 11b)
* SAM-3: Mostly same as SAM-2 but with some differences,
like supporting addressing LUNs < 256 with flat address space.
This means that the same LUN numbers could have different addressing
values. Examples:
* LUN 1:
- SAM representation: 1
- SAM-2 peripheral: 1
- SAM-2 flat addressing: Invalid
- SAM-3 flat addressing: 16384
* LUN 256
- SAM representation: 256
- SAM-2 peripheral: Not possible to represent
- SAM-2 flat addressing: 16640
- SAM-3 flat addressing: 16640
This method makes the transformation from the numerical LUN value to
the right addressing value based on the addressing_mode.
Acceptable values are:
- SAM: 64bit address with no translation
- transparent: Same as SAM but used by drivers that want to use non
supported addressing modes by using the addressing mode
instead of the LUN without being misleading (untested).
- SAM2: Peripheral for LUN < 256 and flat for LUN >= 256. In SAM-2
flat cannot be used for 0-255
- SAM3-flat: Force flat-space addressing
The default is SAM/transparent and nothing will be done with the LUNs.
"""
mode = addressing_mode or constants.SCSI_ADDRESSING_SAM
if mode not in constants.SCSI_ADDRESSING_MODES:
raise exception.InvalidParameterValue('Invalid addressing_mode '
f'{addressing_mode}')
if (mode == constants.SCSI_ADDRESSING_SAM3_FLAT
or (mode == constants.SCSI_ADDRESSING_SAM2 and lun >= 256)):
old_lun = lun
lun += 16384
LOG.info('Transforming LUN value for addressing: %s -> %s',
old_lun, lun)
return lun
def echo_scsi_command(self, path, content) -> None:
"""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) -> Optional[str]:
"""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: str,
force: bool = False,
exc=None,
flush: bool = True) -> None:
"""Removes a scsi device based upon /dev/sdX name."""
path = "/sys/block/%s/device/delete" % device.replace("/dev/", "")
if os.path.exists(path):
exc = exception.ExceptionChainer() if exc is None else exc
if flush:
# flush any outstanding IO first
with exc.context(force, 'Flushing %s failed', device):
self.flush_device_io(device)
LOG.debug("Remove SCSI device %(device)s with %(path)s",
{'device': device, 'path': path})
with exc.context(force, 'Removing %s failed', device):
self.echo_scsi_command(path, "1")
def wait_for_volumes_removal(self, volumes_names: list[str]) -> None:
"""Wait for device paths to be removed from the system."""
str_names = ', '.join(volumes_names)
LOG.debug('Checking to see if SCSI volumes %s have been removed.',
str_names)
exist = ['/dev/' + volume_name for volume_name in volumes_names]
# It can take up to 30 seconds to remove a SCSI device if the path
# failed right before we start detaching, which is unlikely, but we
# still shouldn't fail in that case.
for i in range(61):
exist = [path for path in exist if os.path.exists(path)]
if not exist:
LOG.debug("SCSI volumes %s have been removed.", str_names)
return
# Don't sleep on the last try since we are quitting
if i < 60:
time.sleep(0.5)
# Log every 5 seconds
if i % 10 == 0:
LOG.debug('%s still exist.', ', '.join(exist))
raise exception.VolumePathNotRemoved(volume_path=exist)
def get_device_info(self, device: str) -> dict[str, Optional[str]]:
dev_info = {'device': device, 'host': None,
'channel': None, 'id': None, 'lun': None}
# The input argument 'device' can be of 2 types:
# (a) /dev/disk/by-path/XXX which is a symlink to /dev/sdX device
# (b) /dev/sdX
# If it's a symlink, get the /dev/sdX name first
if os.path.islink(device):
device = '/dev/' + os.readlink(device).split('/')[-1]
# Else it's already a /dev/sdX device.
# Then get it from lsscsi output
(out, _err) = self._execute('lsscsi')
if out:
for line in out.strip().split('\n'):
# The last column of lsscsi is device name
if line.split()[-1] == device:
# The first column of lsscsi is [H:C:T:L]
hctl_info = line.split()[0].strip('[]').split(':')
dev_info['host'] = hctl_info[0]
dev_info['channel'] = hctl_info[1]
dev_info['id'] = hctl_info[2]
dev_info['lun'] = hctl_info[3]
break
LOG.debug('dev_info=%s', str(dev_info))
return dev_info
def get_sysfs_wwn(self, device_names: list[str], mpath=None) -> str:
"""Return the wwid from sysfs in any of devices in udev format."""
# If we have a multipath DM we know that it has found the WWN
if mpath:
# We have the WWN in /uuid even with friendly names, unline /name
try:
with open('/sys/block/%s/dm/uuid' % mpath) as f:
# Contents are matph-WWN, so get the part we want
wwid = f.read().strip()[6:]
if wwid: # Check should not be needed, but just in case
return wwid
except Exception as exc:
LOG.warning('Failed to read the DM uuid: %s', exc)
wwid = self.get_sysfs_wwid(device_names)
glob_str = '/dev/disk/by-id/scsi-'
wwn_paths = glob.glob(glob_str + '*')
# If we don't have multiple designators on page 0x83
if wwid and glob_str + wwid in wwn_paths:
return wwid
# If we have multiple designators use symlinks to find out the wwn
device_names_set = set(device_names)
for wwn_path in wwn_paths:
try:
if os.path.islink(wwn_path) and os.stat(wwn_path):
path = os.path.realpath(wwn_path)
if path.startswith('/dev/'):
name = path[5:]
# Symlink may point to the multipath dm if the attach
# was too fast or we took long to check it. Check
# devices belonging to the multipath DM.
if name.startswith('dm-'):
# Get the devices that belong to the DM
slaves_path = '/sys/class/block/%s/slaves' % name
dm_devs = os.listdir(slaves_path)
# This is the right wwn_path if the devices we have
# attached belong to the dm we followed
if device_names_set.intersection(dm_devs):
break
# This is the right wwn_path if devices we have
elif name in device_names_set:
break
except OSError:
continue
else:
return ''
return wwn_path[len(glob_str):]
def get_sysfs_wwid(self, device_names):
"""Return the wwid from sysfs in any of devices in udev format."""
for device_name in device_names:
try:
with open('/sys/block/%s/device/wwid' % device_name) as f:
wwid = f.read().strip()
except IOError:
continue
# The sysfs wwid has the wwn type in string format as a prefix,
# but udev uses its numerical representation as returned by
# scsi_id's page 0x83, so we need to map it
udev_wwid = self.WWN_TYPES.get(wwid[:4], '8') + wwid[4:]
return udev_wwid
return ''
def get_scsi_wwn(self, path: str) -> str:
"""Read the WWN from page 0x83 value for a SCSI device."""
(out, _err) = self._execute('/lib/udev/scsi_id', '--page', '0x83',
'--whitelisted', path,
run_as_root=True,
root_helper=self._root_helper)
return out.strip()
@staticmethod
def is_multipath_running(enforce_multipath,
root_helper,
execute=None) -> bool:
try:
if execute is None:
execute = priv_rootwrap.execute
cmd = ('multipathd', 'show', 'status')
out, _err = execute(*cmd, run_as_root=True,
root_helper=root_helper)
# There was a bug in multipathd where it didn't return an error
# code and just printed the error message in stdout.
if out and out.startswith('error receiving packet'):
raise putils.ProcessExecutionError('', out, 1, cmd, None)
except putils.ProcessExecutionError as err:
if enforce_multipath:
LOG.error('multipathd is not running: exit code %(err)s',
{'err': err.exit_code})
raise
return False
return True
def get_dm_name(self, dm):
"""Get the Device map name given the device name of the dm on sysfs.
:param dm: Device map name as seen in sysfs. ie: 'dm-0'
:returns: String with the name, or empty string if not available.
ie: '36e843b658476b7ed5bc1d4d10d9b1fde'
"""
try:
with open('/sys/block/' + dm + '/dm/name') as f:
return f.read().strip()
except IOError:
return ''
def find_sysfs_multipath_dm(self, device_names):
"""Find the dm device name given a list of device names
:param device_names: Iterable with device names, not paths. ie: ['sda']
:returns: String with the dm name or None if not found. ie: 'dm-0'
"""
glob_str = '/sys/block/%s/holders/dm-*'
for dev_name in device_names:
dms = glob.glob(glob_str % dev_name)
if dms:
__, device_name, __, dm = dms[0].rsplit('/', 3)
return dm
return None
@staticmethod
def requires_flush(path, path_used, was_multipath):
"""Check if a device needs to be flushed when detaching.
A device representing a single path connection to a volume must only be
flushed if it has been used directly by Nova or Cinder to write data.
If the path has been used via a multipath DM or if the device was part
of a multipath but a different single path was used for I/O (instead of
the multipath) then we don't need to flush.
"""
# No used path happens on failed attachs, when we don't care about
# individual flushes.
if not path_used:
return False
path = os.path.realpath(path)
path_used = os.path.realpath(path_used)
# Need to flush this device if we used this specific path. We check
# this before checking if it's multipath in case we don't detect it
# being multipath correctly (as in bug #1897787).
if path_used == path:
return True
# We flush individual path if Nova didn't use a multipath and we
# replaced the symlink to a real device with a link to the decrypted
# DM. We know we replaced it because it doesn't link to /dev/XYZ,
# instead it maps to /dev/mapped/crypt-XYZ
return not was_multipath and '/dev' != os.path.split(path_used)[0]
def remove_connection(self, devices_names, force=False, exc=None,
path_used=None, was_multipath=False):
"""Remove LUNs and multipath associated with devices names.
:param devices_names: Iterable with real device names ('sda', 'sdb')
:param force: Whether to forcefully disconnect even if flush fails.
:param exc: ExceptionChainer where to add exceptions if forcing
:param path_used: What path was used by Nova/Cinder for I/O
:param was_multipath: If the path used for I/O was a multipath
:returns: Multipath device map name if found and not flushed
"""
if not devices_names:
return
exc = exception.ExceptionChainer() if exc is None else exc
multipath_dm = self.find_sysfs_multipath_dm(devices_names)
LOG.debug('Removing %(type)s devices %(devices)s',
{'type': 'multipathed' if multipath_dm else 'single pathed',
'devices': ', '.join(devices_names)})
multipath_name = multipath_dm and self.get_dm_name(multipath_dm)
if multipath_name:
with exc.context(force, 'Flushing %s failed', multipath_name):
self.flush_multipath_device(multipath_name)
multipath_name = None
multipath_running = True
else:
multipath_running = self.is_multipath_running(
enforce_multipath=False, root_helper=self._root_helper)
for device_name in devices_names:
dev_path = '/dev/' + device_name
if multipath_running:
# Recent multipathd doesn't remove path devices in time when
# it receives mutiple udev events in a short span, so here we
# tell multipathd to remove the path device immediately.
# Even if this step fails, later removing an iscsi device
# triggers a udev event and multipathd can remove the path
# device based on the udev event
self.multipath_del_path(dev_path)
flush = self.requires_flush(dev_path, path_used, was_multipath)
self.remove_scsi_device(dev_path, force, exc, flush)
# Wait until the symlinks are removed
with exc.context(force, 'Some devices remain from %s', devices_names):
try:
self.wait_for_volumes_removal(devices_names)
finally:
# Since we use /dev/disk/by-id/scsi- links to get the wwn we
# must ensure they are always removed.
self._remove_scsi_symlinks(devices_names)
return multipath_name
def _remove_scsi_symlinks(self, devices_names):
devices = ['/dev/' + dev for dev in devices_names]
links = glob.glob('/dev/disk/by-id/scsi-*')
unlink = []
for link in links:
try:
if os.path.realpath(link) in devices:
unlink.append(link)
except OSError:
# A race condition in Python's posixpath:realpath just occurred
# so we can ignore it because the file was just removed between
# a check if file exists and a call to os.readlink
continue
if unlink:
priv_rootwrap.unlink_root(no_errors=True, *unlink)
def flush_device_io(self, device):
"""This is used to flush any remaining IO in the buffers."""
if os.path.exists(device):
try:
# NOTE(geguileo): With 30% connection error rates flush can get
# stuck, set timeout to prevent it from hanging here forever.
# Retry twice after 20 and 40 seconds.
LOG.debug("Flushing IO for device %s", device)
self._execute('blockdev', '--flushbufs', device,
run_as_root=True, attempts=3, timeout=300,
interval=10, root_helper=self._root_helper)
except putils.ProcessExecutionError as exc:
LOG.warning("Failed to flush IO buffers prior to removing "
"device: %(code)s", {'code': exc.exit_code})
raise
def flush_multipath_device(self, device_map_name):
LOG.debug("Flush multipath device %s", device_map_name)
# NOTE(geguileo): With 30% connection error rates flush can get stuck,
# set timeout to prevent it from hanging here forever. Retry twice
# after 20 and 40 seconds.
self._execute('multipath', '-f', device_map_name, run_as_root=True,
attempts=3, timeout=300, interval=10,
root_helper=self._root_helper)
@utils.retry(exception.VolumeDeviceNotFound)
def wait_for_path(self, volume_path):
"""Wait for a path to show up."""
LOG.debug("Checking to see if %s exists yet.",
volume_path)
if not os.path.exists(volume_path):
LOG.debug("%(path)s doesn't exists yet.", {'path': volume_path})
raise exception.VolumeDeviceNotFound(
device=volume_path)
else:
LOG.debug("%s has shown up.", volume_path)
@utils.retry(exception.BlockDeviceReadOnly, retries=5)
def wait_for_rw(self, wwn, device_path):
"""Wait for block device to be Read-Write."""
LOG.debug("Checking to see if %s is read-only.",
device_path)
out, info = self._execute('lsblk', '-o', 'NAME,RO', '-l', '-n')
LOG.debug("lsblk output: %s", out)
blkdevs = out.splitlines()
for blkdev in blkdevs:
# Entries might look like:
#
# "3624a93709a738ed78583fd120013902b (dm-1) 1"
#
# or
#
# "sdd 0"
#
# We are looking for the first and last part of them. For FC
# multipath devices the name is in the format of '<WWN> (dm-<ID>)'
blkdev_parts = blkdev.split(' ')
ro = blkdev_parts[-1]
name = blkdev_parts[0]
# We must validate that all pieces of the dm-# device are rw,
# if some are still ro it can cause problems.
if wwn in name and int(ro) == 1:
LOG.debug("Block device %s is read-only", device_path)
self._execute('multipath', '-r', check_exit_code=[0, 1, 21],
run_as_root=True, root_helper=self._root_helper)
raise exception.BlockDeviceReadOnly(
device=device_path)
else:
LOG.debug("Block device %s is not read-only.", device_path)
def find_multipath_device_path(self, wwn):
"""Look for the multipath device file for a volume WWN.
Multipath devices can show up in several places on
a linux system.
1) When multipath friendly names are ON:
a device file will show up in
/dev/disk/by-id/dm-uuid-mpath-<WWN>
/dev/disk/by-id/dm-name-mpath<N>
/dev/disk/by-id/scsi-mpath<N>
/dev/mapper/mpath<N>
2) When multipath friendly names are OFF:
/dev/disk/by-id/dm-uuid-mpath-<WWN>
/dev/disk/by-id/scsi-<WWN>
/dev/mapper/<WWN>
"""
LOG.info("Find Multipath device file for volume WWN %(wwn)s",
{'wwn': wwn})
# First look for the common path
wwn_dict = {'wwn': wwn}
path = "/dev/disk/by-id/dm-uuid-mpath-%(wwn)s" % wwn_dict
try:
self.wait_for_path(path)
return path
except exception.VolumeDeviceNotFound:
pass
# for some reason the common path wasn't found
# lets try the dev mapper path
path = "/dev/mapper/%(wwn)s" % wwn_dict
try:
self.wait_for_path(path)
return path
except exception.VolumeDeviceNotFound:
pass
# couldn't find a path
LOG.warning("couldn't find a valid multipath device path for "
"%(wwn)s", wwn_dict)
return None
def find_multipath_device(self, device):
"""Discover multipath devices for a mpath device.
This uses the slow multipath -l command to find a
multipath device description, then screen scrapes
the output to discover the multipath device name
and it's devices.
"""
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.warning("multipath call failed exit %(code)s",
{'code': exc.exit_code})
raise exception.CommandExecutionFailed(
cmd='multipath -l %s' % device)
if out:
lines_str = out.strip()
lines = lines_str.split("\n")
lines = [line for line in lines
if not re.match(MULTIPATH_ERROR_REGEX, line) and
len(line)]
if lines:
mdev_name = lines[0].split(" ")[0]
if mdev_name in MULTIPATH_DEVICE_ACTIONS:
mdev_name = lines[0].split(" ")[1]
mdev = '/dev/mapper/%s' % mdev_name
# Confirm that the device is present.
try:
os.stat(mdev)
except OSError:
LOG.warning("Couldn't find multipath device %s",
mdev)
return None
wwid_search = MULTIPATH_WWID_REGEX.search(lines[0])
if wwid_search is not None:
mdev_id = wwid_search.group('wwid')
else:
mdev_id = mdev_name
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,
"name": mdev_name,
"devices": devices}
return info
return None
def multipath_reconfigure(self):
"""Issue a multipathd reconfigure.
When attachments come and go, the multipathd seems
to get lost and not see the maps. This causes
resize map to fail 100%. To overcome this we have
to issue a reconfigure prior to resize map.
"""
(out, _err) = self._execute('multipathd', 'reconfigure',
run_as_root=True,
root_helper=self._root_helper)
return out
def _multipath_resize_map(self, dm_path):
cmd = ('multipathd', 'resize', 'map', dm_path)
(out, _err) = self._execute(*cmd,
run_as_root=True,
root_helper=self._root_helper)
if 'fail' in out or 'timeout' in out:
raise putils.ProcessExecutionError(
stdout=out, stderr=_err,
exit_code=1, cmd=cmd)
return out
def multipath_resize_map(self, dm_path):
"""Issue a multipath resize map on device.
This forces the multipath daemon to update it's
size information a particular multipath device.
:param dm_path: Real path of the DM device (eg: /dev/dm-5)
"""
# "multipathd reconfigure" is async since 0.6.1. While the
# operation is in progress, "multipathd resize map" returns
# "timeout".
tstart = time.time()
while True:
try:
self._multipath_resize_map(dm_path)
break
except putils.ProcessExecutionError as err:
with excutils.save_and_reraise_exception(reraise=True) as ctx:
elapsed = time.time() - tstart
if 'timeout' in err.stdout and (
elapsed < MULTIPATHD_RESIZE_TIMEOUT):
LOG.debug(
"multipathd resize map timed out. "
"Elapsed: %s, timeout: %s. Retrying...",
elapsed, MULTIPATHD_RESIZE_TIMEOUT)
ctx.reraise = False
time.sleep(1)
def extend_volume(self,
volume_paths: list,
use_multipath: bool = False) -> Optional[int]:
"""Signal the SCSI subsystem to test for volume resize.
This function tries to signal the local system's kernel
that an already attached volume might have been resized.
"""
# We need all paths up before extending the devices.
# see Launchpad Bug: #2032177 for more details.
LOG.debug("Checking paths are valid %s", volume_paths)
for volume_path in volume_paths:
if not utils.check_valid_device(self, volume_path):
LOG.error("Path status is down for path %s", volume_path)
raise exception.BrickException("All paths need to be up "
"to extend the device.")
LOG.debug("extend volume %s", volume_paths)
for volume_path in volume_paths:
device = self.get_device_info(volume_path)
LOG.debug("Volume device info = %s", device)
device_id = ("%(host)s:%(channel)s:%(id)s:%(lun)s" %
{'host': device['host'],
'channel': device['channel'],
'id': device['id'],
'lun': device['lun']})
scsi_path = ("/sys/bus/scsi/drivers/sd/%(device_id)s" %
{'device_id': device_id})
size = utils.get_device_size(self, volume_path)
LOG.debug("Starting size: %s", size)
# now issue the device rescan
rescan_path = "%(scsi_path)s/rescan" % {'scsi_path': scsi_path}
self.echo_scsi_command(rescan_path, "1")
new_size = utils.get_device_size(self, volume_path)
LOG.debug("volume size after scsi device rescan %s", new_size)
scsi_wwn = self.get_scsi_wwn(volume_paths[0])
if use_multipath:
mpath_device = self.find_multipath_device_path(scsi_wwn)
if mpath_device:
# Force a reconfigure so that resize works
self.multipath_reconfigure()
size = utils.get_device_size(self, mpath_device)
LOG.info("mpath(%(device)s) current size %(size)s",
{'device': mpath_device, 'size': size})
self.multipath_resize_map(os.path.realpath(mpath_device))
new_size = utils.get_device_size(self, mpath_device)
LOG.info("mpath(%(device)s) new size %(size)s",
{'device': mpath_device, 'size': new_size})
return new_size
def process_lun_id(self, lun_ids):
if isinstance(lun_ids, list):
processed = []
for x in lun_ids:
x = self._format_lun_id(x)
processed.append(x)
else:
processed = self._format_lun_id(lun_ids)
return processed
def _format_lun_id(self, lun_id):
# make sure lun_id is an int
lun_id = int(lun_id)
if lun_id < 256:
return lun_id
else:
return ("0x%04x%04x00000000" %
(lun_id & 0xffff, lun_id >> 16 & 0xffff))
def get_hctl(self, session, lun):
"""Given an iSCSI session return the host, channel, target, and lun."""
glob_str = '/sys/class/iscsi_host/host*/device/session' + session
paths = glob.glob(glob_str + '/target*')
if paths:
__, channel, target = os.path.split(paths[0])[1].split(':')
# Check if we can get the host
else:
target = channel = '-'
paths = glob.glob(glob_str)
if not paths:
LOG.debug('No hctl found on session %s with lun %s', session, lun)
return None
# Extract the host number from the path
host = paths[0][26:paths[0].index('/', 26)]
res = (host, channel, target, lun)
LOG.debug('HCTL %s found on session %s with lun %s', res, session, lun)
return res
def device_name_by_hctl(self, session, hctl):
"""Find the device name given a session and the hctl.
:param session: A string with the session number
:param hctl: An iterable with the host, channel, target, and lun as
passed to scan. ie: ('5', '-', '-', '0')
"""
if '-' in hctl:
hctl = ['*' if x == '-' else x for x in hctl]
path = ('/sys/class/scsi_host/host%(h)s/device/session%(s)s/target'
'%(h)s:%(c)s:%(t)s/%(h)s:%(c)s:%(t)s:%(l)s/block/*' %
{'h': hctl[0], 'c': hctl[1], 't': hctl[2], 'l': hctl[3],
's': session})
# Sort devices and return the first so we don't return a partition
devices = sorted(glob.glob(path))
device = os.path.split(devices[0])[1] if devices else None
LOG.debug('Searching for a device in session %s and hctl %s yield: %s',
session, hctl, device)
return device
def scan_iscsi(self, host, channel='-', target='-', lun='-'):
"""Send an iSCSI scan request given the host and optionally the ctl."""
LOG.debug('Scanning host %(host)s c: %(channel)s, '
't: %(target)s, l: %(lun)s)',
{'host': host, 'channel': channel,
'target': target, 'lun': lun})
self.echo_scsi_command('/sys/class/scsi_host/host%s/scan' % host,
'%(c)s %(t)s %(l)s' % {'c': channel,
't': target,
'l': lun})
def multipath_add_wwid(self, wwid):
"""Add a wwid to the list of know multipath wwids.
This has the effect of multipathd being willing to create a dm for a
multipath even when there's only 1 device.
"""
out, err = self._execute('multipath', '-a', wwid,
run_as_root=True,
check_exit_code=False,
root_helper=self._root_helper)
return out.strip() == "wwid '" + wwid + "' added"
def multipath_add_path(self, realpath):
"""Add a path to multipathd for monitoring.
This has the effect of multipathd checking an already checked device
for multipath.
Together with `multipath_add_wwid` we can create a multipath when
there's only 1 path.
"""
stdout, stderr = self._execute('multipathd', 'add', 'path', realpath,
run_as_root=True, timeout=5,
check_exit_code=False,
root_helper=self._root_helper)
return stdout.strip() == 'ok'
def multipath_del_path(self, realpath):
"""Remove a path from multipathd for monitoring."""
stdout, stderr = self._execute('multipathd', 'del', 'path', realpath,
run_as_root=True, timeout=5,
check_exit_code=False,
root_helper=self._root_helper)
return stdout.strip() == 'ok'
@utils.retry((putils.ProcessExecutionError, exception.BrickException),
retries=3)
def multipath_del_map(self, mpath):
"""Stop monitoring a multipath given its device name (eg: dm-7).
Method ensures that the multipath device mapper actually dissapears
from sysfs.
"""
map_name = self.get_dm_name(mpath)
if map_name:
self._execute('multipathd', 'del', 'map', map_name,
run_as_root=True, timeout=5,
root_helper=self._root_helper)
if map_name and self.get_dm_name(mpath):
raise exception.BrickException("Multipath doesn't go away")
LOG.debug('Multipath %s no longer present', mpath)
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