Mailing List Archive

# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1275980743 -3600
# Node ID 6fe6d5b4cd078b8af930eba79169da70a8ab7d9a
# Parent 63d0f5348af242e6046e1e30d22841ba20f8e6d6
blktap2: Port Xend to the tap-ctl interface.

Signed-off-by: Jake Wires <jake.wires@citrix.com>
---
tools/python/xen/xend/XendDomainInfo.py | 26 ---
tools/python/xen/xend/server/BlktapController.py | 178 +++++++++++++++--------
2 files changed, 124 insertions(+), 80 deletions(-)

diff -r 63d0f5348af2 -r 6fe6d5b4cd07 tools/python/xen/xend/XendDomainInfo.py
--- a/tools/python/xen/xend/XendDomainInfo.py Tue Jun 08 08:05:09 2010 +0100
+++ b/tools/python/xen/xend/XendDomainInfo.py Tue Jun 08 08:05:43 2010 +0100
@@ -63,7 +63,7 @@ from xen.xend.XendAPIConstants import *
from xen.xend.XendAPIConstants import *
from xen.xend.XendCPUPool import XendCPUPool
from xen.xend.server.DevConstants import xenbusState
-from xen.xend.server.BlktapController import TAPDISK_DEVICE, parseDeviceString
+from xen.xend.server.BlktapController import TapdiskController

from xen.xend.XendVMMetrics import XendVMMetrics

@@ -549,15 +549,8 @@ class XendDomainInfo:
dev = xstransact.List(self.vmpath + '/device/tap2')
for x in dev:
path = self.getDeviceController('tap2').readBackend(x, 'params')
- if path and path.startswith(TAPDISK_DEVICE):
- try:
- _minor, _dev, ctrl = parseDeviceString(path)
- #pause the disk
- f = open(ctrl + '/pause', 'w')
- f.write('pause');
- f.close()
- except:
- pass
+ if path and path.startswith(TapdiskController.TAP_DEV):
+ TapdiskController.pause(path)
except Exception, ex:
log.warn('Could not pause blktap disk.');

@@ -578,17 +571,8 @@ class XendDomainInfo:
dev = xstransact.List(self.vmpath + '/device/tap2')
for x in dev:
path = self.getDeviceController('tap2').readBackend(x, 'params')
- if path and path.startswith(TAPDISK_DEVICE):
- try:
- #Figure out the sysfs path.
- _minor, _dev, ctrl = parseDeviceString(path)
- #unpause the disk
- if(os.path.exists(ctrl + '/resume')):
- f = open(ctrl + '/resume', 'w');
- f.write('resume');
- f.close();
- except:
- pass
+ if path and path.startswith(TapdiskController.TAP_DEV):
+ TapdiskController.unpause(path)

except Exception, ex:
log.warn('Could not unpause blktap disk: %s' % str(ex));
diff -r 63d0f5348af2 -r 6fe6d5b4cd07 tools/python/xen/xend/server/BlktapController.py
--- a/tools/python/xen/xend/server/BlktapController.py Tue Jun 08 08:05:09 2010 +0100
+++ b/tools/python/xen/xend/server/BlktapController.py Tue Jun 08 08:05:43 2010 +0100
@@ -1,5 +1,5 @@
# Copyright (c) 2005, XenSource Ltd.
-import string, re
+import string, re, os

from xen.xend.server.blkif import BlkifController
from xen.xend.XendLogging import log
@@ -7,11 +7,6 @@ from xen.util.xpopen import xPopen3

phantomDev = 0;
phantomId = 0;
-
-TAPDISK_SYSFS = '/sys/class/blktap2'
-TAPDISK_BINARY = '/usr/sbin/tapdisk2'
-TAPDISK_DEVICE = '/dev/xen/blktap-2/tapdev'
-TAPDISK_CONTROL = TAPDISK_SYSFS + '/blktap'

blktap1_disk_types = [.
'aio',
@@ -42,20 +37,6 @@ def doexec(args, inputtext=None):
stderr = proc.childerr
rc = proc.wait()
return (rc,stdout,stderr)
-
-def parseDeviceString(device):
- if device.find('/dev') == -1:
- raise Exception, 'invalid tap device: ' + device
-
- pattern = re.compile(TAPDISK_DEVICE + '(\d+)$')
- groups = pattern.search(device)
- if not groups:
- raise Exception, 'malformed tap device: ' + device
-
- minor = groups.group(1)
- control = TAPDISK_CONTROL + minor
-
- return minor, device, control

# blktap1 device controller
class BlktapController(BlkifController):
@@ -179,18 +160,10 @@ class Blktap2Controller(BlktapController
(typ, params, file) = string.split(uname, ':', 2)
subtyp = 'tapdisk'

- #check for blktap2 installation.
- blktap2_installed=0;
- (rc,stdout, stderr) = doexec("cat /proc/devices");
- out = stdout.read();
- stdout.close();
- stderr.close();
- if( out.find("blktap2") >= 0 ):
- blktap2_installed=1;
-
if typ in ('tap'):
if subtyp in ('tapdisk', 'ioemu'):
- if params not in blktap2_disk_types or not blktap2_installed:
+ if params not in blktap2_disk_types or \
+ TapdiskController.check():
# pass this device off to BlktapController
log.warn('WARNING: using deprecated blktap module')
self.deviceClass = 'tap'
@@ -198,22 +171,7 @@ class Blktap2Controller(BlktapController
self.deviceClass = 'tap2'
return devid

- if self.vm.image and self.vm.image.memory_sharing:
- cmd = [. TAPDISK_BINARY, '-n', '%s:%s' % (params, file), '-s', '%d' % self.vm.getDomid() ]
- else:
- cmd = [ TAPDISK_BINARY, '-n', '%s:%s' % (params, file) ]
- (rc,stdout,stderr) = doexec(cmd)
-
- if rc != 0:
- err = stderr.read();
- out = stdout.read();
- stdout.close();
- stderr.close();
- raise Exception, 'Failed to create device.\n stdout: %s\n stderr: %s\nCheck that target \"%s\" exists and that blktap2 driver installed in dom0.' % (out.rstrip(), err.rstrip(), file);
-
- minor, device, control = parseDeviceString(stdout.readline())
- stdout.close();
- stderr.close();
+ device = TapdiskController.create(params, file)

# modify the configutration to create a blkback for the underlying
# blktap2 device. Note: we need to preserve the original tapdisk uname
@@ -226,8 +184,7 @@ class Blktap2Controller(BlktapController
config.pop('tapdisk_uname')
return devid

- # The new blocktap implementation requires a sysfs signal to close
- # out disks. This function is called from a thread when the
+ # This function is called from a thread when the
# domain is detached from the disk.
def finishDeviceCleanup(self, backpath, path):
"""Perform any device specific cleanup
@@ -239,14 +196,117 @@ class Blktap2Controller(BlktapController

#Figure out what we're going to wait on.
self.waitForBackend_destroy(backpath)
-
- #Figure out the sysfs path.
- minor, dev, ctrl = parseDeviceString(path)
-
- #Close out the disk
- f = open(ctrl + '/remove', 'w')
- f.write('remove');
- f.close()
-
- return
-
+ TapdiskController.destroy(path)
+
+class TapdiskException(Exception):
+ pass
+
+class TapdiskController(object):
+ '''class which encapsulates all tapdisk control operations'''
+
+ TAP_CTL = 'tap-ctl'
+ TAP_DEV = '/dev/xen/blktap-2/tapdev'
+
+ class Tapdisk(object):
+ def __init__(self, pid=None, minor=-1, state=None,
+ dtype='', image=None, device=None):
+ self.pid = pid
+ self.minor = minor
+ self.state = state
+ self.dtype = dtype
+ self.image = image
+ self.device = device
+
+ def __str__(self):
+ return 'image=%s pid=%s minor=%s state=%s type=%s device=%s' \
+ % (self.image, self.pid, self.minor, self.state, self.dtype,
+ self.device)
+
+ @staticmethod
+ def exc(*args):
+ rc, stdout, stderr = doexec([TapdiskController.TAP_CTL] + list(args))
+ out, err = stdout.read().strip(), stderr.read().strip()
+ stdout.close()
+ stderr.close()
+ if rc:
+ raise TapdiskException('%s failed (%s %s %s)' % \
+ (args, rc, out, err))
+ return out
+
+ @staticmethod
+ def check():
+ try:
+ TapdiskController.exc('check')
+ return 0
+ except Exception, e:
+ log.warn("tapdisk2 check failed: %s" % e)
+ return -1
+
+ @staticmethod
+ def list():
+ tapdisks = []
+
+ _list = TapdiskController.exc('list')
+ if not _list: return []
+
+ for line in _list.split('\n'):
+ tapdisk = TapdiskController.Tapdisk()
+
+ for pair in line.split():
+ key, value = pair.split('=')
+ if key == 'pid':
+ tapdisk.pid = value
+ elif key == 'minor':
+ tapdisk.minor = int(value)
+ if tapdisk.minor >= 0:
+ tapdisk.device = '%s%s' % \
+ (TapdiskController.TAP_DEV, tapdisk.minor)
+ elif key == 'state':
+ tapdisk.state = value
+ elif key == 'args' and value.find(':') != -1:
+ tapdisk.dtype, tapdisk.image = value.split(':')
+
+ tapdisks.append(tapdisk)
+
+ return tapdisks
+
+ @staticmethod
+ def fromDevice(device):
+ if device.startswith(TapdiskController.TAP_DEV):
+ minor = os.minor(os.stat(device).st_rdev)
+ tapdisks = filter(lambda x: x.minor == minor,
+ TapdiskController.list())
+ if len(tapdisks) == 1:
+ return tapdisks[0]
+ return None
+
+ @staticmethod
+ def create(dtype, image):
+ return TapdiskController.exc('create', '-a%s:%s' % (dtype, image))
+
+ @staticmethod
+ def destroy(device):
+ tapdisk = TapdiskController.fromDevice(device)
+ if tapdisk:
+ if tapdisk.pid:
+ TapdiskController.exc('destroy',
+ '-p%s' % tapdisk.pid,
+ '-m%s' % tapdisk.minor)
+ else:
+ TapdiskController.exc('free', '-m%s' % tapdisk.minor)
+
+ @staticmethod
+ def pause(device):
+ tapdisk = TapdiskController.fromDevice(device)
+ if tapdisk and tapdisk.pid:
+ TapdiskController.exc('pause',
+ '-p%s' % tapdisk.pid,
+ '-m%s' % tapdisk.minor)
+
+ @staticmethod
+ def unpause(device):
+ tapdisk = TapdiskController.fromDevice(device)
+ if tapdisk and tapdisk.pid:
+ TapdiskController.exc('unpause',
+ '-p%s' % tapdisk.pid,
+ '-m%s' % tapdisk.minor)

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