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https://github.com/xen-project/xen.git
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cl349@firebug.cl.cam.ac.uk
78552ee77c
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
335 lines
11 KiB
Python
Executable File
335 lines
11 KiB
Python
Executable File
#============================================================================
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of version 2.1 of the GNU Lesser General Public
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# License as published by the Free Software Foundation.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#============================================================================
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# Copyright (C) 2004, 2005 Mike Wray <mike.wray@hp.com>
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#============================================================================
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"""Support for virtual block devices.
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"""
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import string
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from xen.util import blkif
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from xen.xend.XendError import XendError, VmError
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from xen.xend.XendRoot import get_component
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from xen.xend.XendLogging import log
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from xen.xend import sxp
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from xen.xend import Blkctl
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from xen.xend.xenstore import DBVar
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from xen.xend.server.controller import Dev, DevController
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class BlkifBackend:
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""" Handler for the 'back-end' channel to a block device driver domain
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on behalf of a front-end domain.
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Must be connected using connect() before it can be used.
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"""
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def __init__(self, controller, id, dom, recreate=False):
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self.controller = controller
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self.id = id
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self.frontendDomain = self.controller.getDomain()
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self.backendDomain = dom
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self.destroyed = False
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self.connected = False
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self.status = None
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def init(self, recreate=False, reboot=False):
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self.destroyed = False
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self.status = BLKIF_INTERFACE_STATUS_DISCONNECTED
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self.frontendDomain = self.controller.getDomain()
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def __str__(self):
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return ('<BlkifBackend frontend=%d backend=%d id=%d>'
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% (self.frontendDomain,
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self.backendDomain,
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self.id))
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def getId(self):
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return self.id
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def connect(self, recreate=False):
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"""Connect to the blkif control interface.
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@param recreate: true if after xend restart
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"""
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log.debug("Connecting blkif %s", str(self))
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if recreate or self.connected:
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self.connected = True
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pass
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def destroy(self, change=False, reboot=False):
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"""Disconnect from the blkif control interface and destroy it.
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"""
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self.destroyed = True
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# For change true need to notify front-end, or back-end will do it?
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def connectInterface(self, val):
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self.status = BLKIF_INTERFACE_STATUS_CONNECTED
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def interfaceDisconnected(self):
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self.status = BLKIF_INTERFACE_STATUS_DISCONNECTED
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class BlkDev(Dev):
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"""Info record for a block device.
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"""
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__exports__ = Dev.__exports__ + [
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DBVar('dev', ty='str'),
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DBVar('vdev', ty='int'),
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DBVar('mode', ty='str'),
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DBVar('viftype', ty='str'),
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DBVar('params', ty='str'),
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DBVar('node', ty='str'),
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DBVar('device', ty='long'),
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DBVar('dev_handle', ty='long'),
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DBVar('start_sector', ty='long'),
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DBVar('nr_sectors', ty='long'),
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]
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def __init__(self, controller, id, config, recreate=False):
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Dev.__init__(self, controller, id, config, recreate=recreate)
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self.dev = None
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self.uname = None
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self.vdev = None
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self.mode = None
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self.type = None
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self.params = None
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self.node = None
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self.device = None
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self.dev_handle = 0
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self.start_sector = None
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self.nr_sectors = None
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self.frontendDomain = self.getDomain()
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self.backendDomain = None
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self.backendId = 0
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self.configure(self.config, recreate=recreate)
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def exportToDB(self, save=False):
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Dev.exportToDB(self, save=save)
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backend = self.getBackend()
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def init(self, recreate=False, reboot=False):
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self.frontendDomain = self.getDomain()
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backend = self.getBackend()
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self.backendId = backend.id
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def configure(self, config, change=False, recreate=False):
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if change:
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raise XendError("cannot reconfigure vbd")
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self.config = config
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self.uname = sxp.child_value(config, 'uname')
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if not self.uname:
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raise VmError('vbd: Missing uname')
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# Split into type and type-specific params (which are passed to the
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# type-specific control script).
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(self.type, self.params) = string.split(self.uname, ':', 1)
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self.dev = sxp.child_value(config, 'dev')
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if not self.dev:
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raise VmError('vbd: Missing dev')
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self.mode = sxp.child_value(config, 'mode', 'r')
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self.vdev = blkif.blkdev_name_to_number(self.dev)
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if not self.vdev:
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raise VmError('vbd: Device not found: %s' % self.dev)
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try:
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xd = get_component('xen.xend.XendDomain')
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self.backendDomain = xd.domain_lookup_by_name(sxp.child_value(config, 'backend', '0')).id
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except:
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raise XendError('invalid backend domain')
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return self.config
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def attach(self, recreate=False, change=False):
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if recreate:
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pass
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else:
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node = Blkctl.block('bind', self.type, self.params)
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self.setNode(node)
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self.attachBackend()
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if change:
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self.interfaceChanged()
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def unbind(self):
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if self.node is None: return
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log.debug("Unbinding vbd (type %s) from %s"
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% (self.type, self.node))
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Blkctl.block('unbind', self.type, self.node)
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def setNode(self, node):
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# NOTE:
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# This clause is testing code for storage system experiments.
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# Add a new disk type that will just pass an opaque id in the
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# dev_handle and use an experimental device type.
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# Please contact andrew.warfield@cl.cam.ac.uk with any concerns.
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if self.type == 'parallax':
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self.node = node
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self.device = 61440 # (240,0)
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self.dev_handle = long(self.params)
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self.nr_sectors = long(0)
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return
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# done.
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mounted_mode = self.check_mounted(node)
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if not '!' in self.mode and mounted_mode:
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if mounted_mode == "w":
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raise VmError("vbd: Segment %s is in writable use" %
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self.uname)
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elif 'w' in self.mode:
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raise VmError("vbd: Segment %s is in read-only use" %
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self.uname)
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segment = blkif.blkdev_segment(node)
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if not segment:
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raise VmError("vbd: Segment not found: uname=%s" % self.uname)
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self.node = node
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self.device = segment['device']
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self.start_sector = segment['start_sector']
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self.nr_sectors = segment['nr_sectors']
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def check_mounted(self, name):
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mode = blkif.mount_mode(name)
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xd = get_component('xen.xend.XendDomain')
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for vm in xd.list():
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ctrl = vm.getDeviceController(self.getType(), error=False)
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if (not ctrl): continue
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for dev in ctrl.getDevices():
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if dev is self: continue
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if dev.type == 'phy' and name == blkif.expand_dev_name(dev.params):
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mode = dev.mode
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if 'w' in mode:
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return 'w'
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if mode and 'r' in mode:
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return 'r'
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return None
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def readonly(self):
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return 'w' not in self.mode
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def sxpr(self):
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val = ['vbd',
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['id', self.id],
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['vdev', self.vdev],
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['device', self.device],
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['mode', self.mode]]
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if self.dev:
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val.append(['dev', self.dev])
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if self.uname:
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val.append(['uname', self.uname])
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if self.node:
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val.append(['node', self.node])
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return val
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def getBackend(self):
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return self.controller.getBackend(self.backendDomain)
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def refresh(self):
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log.debug("Refreshing vbd domain=%d id=%s", self.frontendDomain,
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self.id)
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self.interfaceChanged()
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def destroy(self, change=False, reboot=False):
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"""Destroy the device. If 'change' is true notify the front-end interface.
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@param change: change flag
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"""
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self.destroyed = True
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log.debug("Destroying vbd domain=%d id=%s", self.frontendDomain,
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self.id)
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if change:
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self.interfaceChanged()
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self.unbind()
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def interfaceChanged(self):
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"""Tell the back-end to notify the front-end that a device has been
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added or removed.
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"""
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self.getBackend().interfaceChanged()
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def attachBackend(self):
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"""Attach the device to its controller.
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"""
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self.getBackend().connect()
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class BlkifController(DevController):
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"""Block device interface controller. Handles all block devices
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for a domain.
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"""
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def __init__(self, vm, recreate=False):
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"""Create a block device controller.
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"""
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DevController.__init__(self, vm, recreate=recreate)
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self.backends = {}
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self.backendId = 0
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def initController(self, recreate=False, reboot=False):
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self.destroyed = False
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if reboot:
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self.rebootBackends()
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self.rebootDevices()
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def sxpr(self):
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val = ['blkif', ['dom', self.getDomain()]]
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return val
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def rebootBackends(self):
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for backend in self.backends.values():
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backend.init(reboot=True)
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def getBackendById(self, id):
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return self.backends.get(id)
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def getBackendByDomain(self, dom):
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for backend in self.backends.values():
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if backend.backendDomain == dom:
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return backend
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return None
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def getBackend(self, dom):
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backend = self.getBackendByDomain(dom)
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if backend: return backend
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backend = BlkifBackend(self, self.backendId, dom)
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self.backendId += 1
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self.backends[backend.getId()] = backend
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backend.init()
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return backend
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def newDevice(self, id, config, recreate=False):
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"""Create a device..
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@param id: device id
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@param config: device configuration
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@param recreate: if true it's being recreated (after xend restart)
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@type recreate: bool
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@return: device
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@rtype: BlkDev
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"""
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return BlkDev(self, id, config, recreate=recreate)
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def destroyController(self, reboot=False):
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"""Destroy the controller and all devices.
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"""
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self.destroyed = True
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log.debug("Destroying blkif domain=%d", self.getDomain())
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self.destroyDevices(reboot=reboot)
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self.destroyBackends(reboot=reboot)
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def destroyBackends(self, reboot=False):
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for backend in self.backends.values():
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backend.destroy(reboot=reboot)
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