3:44 a.m.
Hello,
I logged a bug about using virsh detach-disk cleaning up all sanlock resources for the
domain instead of only the device in question.
After a quick look into the code, I think a new method similar to
virLockManagerSanlockAddResource is needed in case of detaching a disk from the domain,
like e.g. virLockManagerSanlockDelResource (…).
Now it looks like virLockManagerSanlockRelease is called, which releases all resources:
if ((rv = sanlock_release(-1, priv->vm_pid, SANLK_REL_ALL, 0, NULL)) < 0) {
virsh detach-disk should then call virLockManagerSanlockDelResource for the given resource
imo.
Any thoughts about this or why it is implemented like this?
--
Frido Roose
3:46 a.m.
On Thursday 31 May 2012 at 10:44, Frido Roose wrote:
Hello,
I logged a bug about using virsh detach-disk cleaning up all sanlock
resources for the domain instead of only the device in question.
After a quick look into the code, I think a new method similar to
virLockManagerSanlockAddResource is needed in case of detaching a disk from
the domain, like e.g. virLockManagerSanlockDelResource (…).
Now it looks like virLockManagerSanlockRelease is called, which releases
all resources:
if ((rv = sanlock_release(-1, priv->vm_pid, SANLK_REL_ALL, 0, NULL)) < 0) {
virsh detach-disk should then call virLockManagerSanlockDelResource for the
given resource imo.
Any thoughts about this or why it is implemented like this?
With the help of some debugging output and the source code, new questions
arise:
Reproducing the problem
===================
10:10:47 pan ~ # virsh domblklist vmor01
Target Source
------------------------------------------------
vda /var/lib/libvirt/images/vmor01.img
vdb /dev/disk/by-id/wwn-0x600a0b80002695880000cc4c4f865710
10:10:51 pan ~ # sanlock client status
daemon b7baf6f0-2d9b-4b6f-be1e-2169284c68a0.pan
p -1 listener
p 9846
p -1 status
s __LIBVIRT__DISKS__:14:/var/lib/libvirt/sanlock/__LIBVIRT__DISKS__:0
r
__LIBVIRT__DISKS__:d540f8af975019b0d41c4c65e4955072:/var/lib/libvirt/sanlock/d540f8af975019b0d41c4c65e4955072:0:11
p 9846
r
__LIBVIRT__DISKS__:571a282fc5e8cbb42167ce9ec1d41a95:/var/lib/libvirt/sanlock/571a282fc5e8cbb42167ce9ec1d41a95:0:10
p 9846
10:10:53 pan ~ # virsh detach-disk vmor01 vdb
Disk detached successfully
10:11:39 pan ~ # sanlock client status
daemon b7baf6f0-2d9b-4b6f-be1e-2169284c68a0.pan
p -1 listener
p 9846
p -1 status
s __LIBVIRT__DISKS__:14:/var/lib/libvirt/sanlock/__LIBVIRT__DISKS__:0
DEBUG output
============
2012-06-01 08:11:39.198+0000: 9718: debug : virDomainLockManagerNew:123 :
plugin=0x7fa5240cb4f0 dom=0x7fa52419d460 withResources=0
2012-06-01 08:11:39.198+0000: 9718: debug : virLockManagerNew:291 :
plugin=0x7fa5240cb4f0 type=0 nparams=4 params=0x7fa533cdf8d0 flags=0
2012-06-01 08:11:39.198+0000: 9718: debug : virLockManagerLogParams:98 :
key=uuid type=uuid value=c0ee1dfa-4056-f3f9-9f8c-f10e974b59f0
2012-06-01 08:11:39.198+0000: 9718: debug : virLockManagerLogParams:94 :
key=name type=string value=vmor01
2012-06-01 08:11:39.198+0000: 9718: debug : virLockManagerLogParams:82 :
key=id type=uint value=1
2012-06-01 08:11:39.198+0000: 9718: debug : virLockManagerLogParams:82 :
key=pid type=uint value=9846
2012-06-01 08:11:39.198+0000: 9718: debug : virDomainLockManagerAddDisk:86
: Add disk /dev/disk/by-id/wwn-0x600a0b80002695880000cc4c4f865710
2012-06-01 08:11:39.198+0000: 9718: debug : virLockManagerAddResource:320 :
lock=0x7fa524198360 type=0
name=/dev/disk/by-id/wwn-0x600a0b80002695880000cc4c4f865710 nparams=0
params=(nil) flags=0
2012-06-01 08:11:39.198+0000: 9718: debug : virLockManagerRelease:352 :
lock=0x7fa524198360 state=(nil) flags=0
2012-06-01 08:11:39.214+0000: 9718: debug : virLockManagerFree:374 :
lock=0x7fa524198360
SOURCE
========
qemuDomainDetachDiskDevice or
qemuDomainDetachPciDiskDevice calls virDomainLockDiskDetach
(src/locking/domain_lock.c):
int virDomainLockDiskDetach(virLockManagerPluginPtr plugin,
virDomainObjPtr dom,
virDomainDiskDefPtr disk)
{
virLockManagerPtr lock;
int ret = -1;
if (!(lock = virDomainLockManagerNew(plugin, dom, false)))
return -1;
if (virDomainLockManagerAddDisk(lock, disk) < 0)
goto cleanup;
if (virLockManagerRelease(lock, NULL, 0) < 0)
goto cleanup;
ret = 0;
cleanup:
virLockManagerFree(lock);
return ret;
}
I wondered why virDomainLockManagerAddDisk is called when detaching a disk
device. It even looks like this succeeds and then virLockManagerRelease is
called, which cleans up all sanlock resources for the domain.
I suspect a function like virDomainLockManagerRemoveDisk(lock, disk) should
be called at this point that releases the specific disk, which does not yet
exist.
Only virLockDriverAddResource exists in the _virLockDriver struct.
I have the feeling that this sanlock is not completely implemented yet? Or
am I missing something big?
Best regards,
Frido Roose
9:46 a.m.
On 06/01/2012 02:46 AM, Frido Roose wrote:
I wondered why virDomainLockManagerAddDisk is called when detaching a disk
device. It even looks like this succeeds and then virLockManagerRelease is
called, which cleans up all sanlock resources for the domain.
I suspect a function like virDomainLockManagerRemoveDisk(lock, disk) should
be called at this point that releases the specific disk, which does not yet
exist.
Yes, that sounds reasonable.
Only virLockDriverAddResource exists in the _virLockDriver struct.
I have the feeling that this sanlock is not completely implemented yet? Or
am I missing something big?
You are correct that no one has coded it yet - since it seems to be your
itch, would you mind taking a stab at writing the patch to add it?
--
Eric Blake eblake(a)redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
8:45 a.m.
On Fri, Jun 01, 2012 at 10:46:04AM +0200, Frido Roose wrote:
On Thursday 31 May 2012 at 10:44, Frido Roose wrote:
Hello,
I logged a bug about using virsh detach-disk cleaning up all sanlock
resources for the domain instead of only the device in question.
After a quick look into the code, I think a new method similar to
virLockManagerSanlockAddResource is needed in case of detaching a disk from
the domain, like e.g. virLockManagerSanlockDelResource (…).
Now it looks like virLockManagerSanlockRelease is called, which releases
all resources:
if ((rv = sanlock_release(-1, priv->vm_pid, SANLK_REL_ALL, 0, NULL)) < 0) {
virsh detach-disk should then call virLockManagerSanlockDelResource for the
given resource imo.
You are a little mixed up with the sanlock API naming here vs the hotplug
hotunplug actions.
The way sanlock works is that you do
- Connect to sanlock
- Register all the disks that will be operated on using
virLockManagerSanlockAddResource
- Invoke the acquire/inquire/release actions on sanlock
In other words, using 'AddResource' is correct, even when
releasing a resource/lease.
The problem is that the usage of SANLK_REL_ALL is wrong. We should
be using the res_args + res_count fields to pass the explicit list
of disks, instead of releasing all of them.
Daniel
--
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4:53 a.m.
On Friday 8 June 2012 at 15:45, Daniel P. Berrange wrote:
You are a little mixed up with the sanlock API naming here vs the hotplug
hotunplug actions.
The way sanlock works is that you do
- Connect to sanlock
- Register all the disks that will be operated on using
virLockManagerSanlockAddResource
- Invoke the acquire/inquire/release actions on sanlock
In other words, using 'AddResource' is correct, even when
releasing a resource/lease.
The problem is that the usage of SANLK_REL_ALL is wrong. We should
be using the res_args + res_count fields to pass the explicit list
of disks, instead of releasing all of them.
You are absolutely right, I was confused about the naming.
I found some time this weekend to take a look into the code again and changed to code as
you suggested.
I compiled and tested the patch, and the release of the resource looks fine now. Only the
specific resource/disk is being removed from sanlock now, while the others stay
registered.
You find the patch included in this message.
Thanks for the help!
BR,
Frido
6:10 a.m.
I compiled and tested the patch, and the release of the resource
looks fine now. Only the specific resource/disk is being removed from sanlock now, while
the others stay registered.
Hold on, despite the behavior is as expected with the patch, there seems to be an issue
with the return value or check:
2012-07-09 10:53:29.105+0000: 6686: debug : virLockManagerAddResource:320 :
lock=0x7f22e8009b60 type=0 name=/var/lib/libvirt/images/testlun2.img nparams=0
params=(nil) flags=0
2012-07-09 10:53:29.105+0000: 6686: debug : virLockManagerRelease:352 :
lock=0x7f22e8009b60 state=(nil) flags=0
2012-07-09 10:53:29.105+0000: 6686: error : virLockManagerSanlockRelease:842 : Failed to
release lock: Operation not permitted
2012-07-09 10:53:29.105+0000: 6686: debug : virLockManagerFree:374 : lock=0x7f22e8009b60
2012-07-09 10:53:29.105+0000: 6686: warning : qemuDomainDetachPciDiskDevice:1356 : Unable
to release lock on /var/lib/libvirt/images/testlun2.img
The disk resource is however removed from the domain, and from sanlock (as exposed with:
sanlock client status) as we expected it to be.
Probably something is missing in the return value handling.
Fyi,
Frido
5:27 p.m.
Hold on, despite the behavior is as expected with the patch, there
seems to be an issue with the return value or check:
Problem found: the res_count variable was not properly initialized causing the improper
return values.
Included a new patch which I have tested again by hot-attaching/detaching disk devices.
Debug output looks fine now, sanlock behavior as expected.
Could someone review this?
Thanks,
Frido
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participants (3)
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Daniel P. Berrange -
Eric Blake -
Frido Roose