Fix/cleanup destoryDevice code path

More subtle problems with destroyDevice code path in xend. See attached patch

Regards,
Jim

# HG changeset patch
# User Jim Fehlig <[email protected]>
# Date 1186081049 21600
# Node ID 430ae0d3a333ff4d212df7c2313caa03e8f4dd51 # Parent 88bb0d305308a2cab31fd8559a6a2719db1ea55a Fix/cleanup destroyDevice code path in xend.

When calling destroyDevice code path (e.g. xm block-detach dom devid), allow specifying an integer device id or a device name such as xvdN or /dev/xvdN. Allowing the /dev/xvdN form is useful when detaching devices from dom0. Bootloaders may do this to unmount a disk previously mounted in dom0.

Move examination of device ID format into the DevController, permitting device controllers to determine a valid device ID instead of higher level code.

Signed-off-by Jim Fehlig <[email protected]>

diff -r 88bb0d305308 -r 430ae0d3a333 tools/python/xen/xend/XendDomainInfo.py

tools/python/xen/xend/XendDomainInfo.py Thu Aug 02 12:57:29 2007 -0600 renamed from tools/python/xen/xend/XendDomainInfo.py Wed Aug 01 15:47:54 2007 +0100 +2 -12

@@ -559,18 +559,8 @@ class XendDomainInfo:
             self.getDeviceController(devclass).waitForDevices()
 
     def destroyDevice(self, deviceClass, devid, force = False):
-        try:
-            dev = int(devid)
-        except ValueError:
-            # devid is not a number but a string containing either device
-            # name (e.g. xvda) or device_type/device_id (e.g. vbd/51728)
-            dev = type(devid) is str and devid.split('/')[-1] or None
-            if dev == None:
-                log.debug("Could not find the device %s", devid)
-                return None
-
-        log.debug("dev = %s", dev)
-        return 
 self.getDeviceController(deviceClass).destroyDevice(dev, force)
+        log.debug("dev = %s", devid)
+        return 
 self.getDeviceController(deviceClass).destroyDevice(devid, force)
 

def getDeviceSxprs(self, deviceClass):
if self._stateGet() in (DOM_STATE_RUNNING, DOM_STATE_PAUSED):
diff -r 88bb0d305308 -r 430ae0d3a333 tools/python/xen/xend/server/DevController.py
--- a/tools/python/xen/xend/server/DevController.py Wed Aug 01
15:47:54 2007 +0100
+++ b/tools/python/xen/xend/server/DevController.py Thu Aug 02
12:57:29 2007 -0600

tools/python/xen/xend/XendDomainInfo.py Thu Aug 02 12:57:29 2007 -0600 renamed from tools/python/xen/xend/XendDomainInfo.py Wed Aug 01 15:47:54 2007 +0100 +0 -0

@@ -203,27 +203,32 @@ class DevController:
 
         The implementation here simply deletes the appropriate 

paths from the
store. This may be overridden by subclasses who need to
perform other

tools/python/xen/xend/XendDomainInfo.py Thu Aug 02 12:57:29 2007 -0600 renamed from tools/python/xen/xend/XendDomainInfo.py Wed Aug 01 15:47:54 2007 +0100 +16 -11

-        tasks on destruction.  Further, the implementation here can only
-        accept integer device IDs, or values that can be converted to
-        integers.  Subclasses may accept other values and convert them to
-        integers before passing them here.
-        """
-
-        devid = int(devid)
+        tasks on destruction. The implementation here accepts integer device
+        IDs or paths containg integer deviceIDs, e.g. vfb/0.  Subclasses may
+        accept other values and convert them to integers before passing them
+        here.
+        """
+
+        try:
+            dev = int(devid)
+        except ValueError:
+            # Does devid contain devicetype/deviceid?
+            # Propogate exception if unable to find an integer devid
+            dev = int(type(devid) is str and devid.split('/')[-1] or None)
 
         # Modify online status /before/ updating state (latter is watched by
         # drivers, so this ordering avoids a race).
-        self.writeBackend(devid, 'online', "0")
-        self.writeBackend(devid, 'state', str(xenbusState['Closing']))
+        self.writeBackend(dev, 'online', "0")
+        self.writeBackend(dev, 'state', str(xenbusState['Closing']))
 
         if force:
-            frontpath = self.frontendPath(devid)
+            frontpath = self.frontendPath(dev)
             backpath = xstransact.Read(frontpath, "backend")
             if backpath:
                 xstransact.Remove(backpath)
             xstransact.Remove(frontpath)
 
-        self.vm._removeVm("device/%s/%d" % (self.deviceClass, devid))
+        self.vm._removeVm("device/%s/%d" % (self.deviceClass, dev))
 
     def configurations(self):
         return map(self.configuration, self.deviceIDs())

diff -r 88bb0d305308 -r 430ae0d3a333 tools/python/xen/xend/server/blkif.py

tools/python/xen/xend/server/blkif.py Thu Aug 02 12:57:29 2007 -0600 renamed from tools/python/xen/xend/server/blkif.py Wed Aug 01 15:47:54 2007 +0100 +9 -6

@@ -149,13 +149,16 @@ class BlkifController(DevController):
     def destroyDevice(self, devid, force):
         """@see DevController.destroyDevice"""
 
-        # If we are given a device name, then look up the device ID from it,
-        # and destroy that ID instead.  If what we are given is an integer,
-        # then assume it's a device ID and pass it straight through to our
-        # superclass's method.
-
+        # vbd device IDs can be either string or integer.  Further, the
+        # following string values are possible:
+        #    - devicetype/deviceid (vbd/51728)
+        #    - devicetype/devicename (/dev/xvdb)
+        #    - devicename (xvdb)
+        # Let our superclass handle integer or devicetype/deviceid forms.
+        # If we are given a device name form, then look up the device ID
+        # from it, and destroy that ID instead.
         try:
-            DevController.destroyDevice(self, int(devid), force)
+            DevController.destroyDevice(self, devid, force)
         except ValueError:
             devid_end = type(devid) is str and devid.split('/')[-1] or None
 

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Jim

Can you check if this removes the device nodes within xenstore when doing xm save [1] - as I modified this section of code to fix up a problem with just that not so long ago. Unfortunately, I'm not able to test it myself, as I'm "without a xen-capable machine at the moment".

I have no particular reason to believe it DOESN'T do that, I'm just asking to make sure that it's destroyed properly, because I found that leaving lots of device info in xenstore bloats the database in xenstore, and eventually Dom0 runs out of physical memory.... :-(