Re: [libvirt] [PATCH] qemu: call endjob in RevertToSnapshot
On 08/28/2014 10:09 AM, Jincheng Miao wrote: On 08/27/2014 07:52 PM, Eric Blake wrote: On 08/27/2014 03:20 AM, Jincheng Miao wrote: On 08/27/2014 11:02 AM, Eric Blake wrote: On 08/26/2014 08:10 PM, Jincheng Miao wrote: In qemuDomainRevertToSnapshot(), it will check snap->def->state. But when the state is PMSUSPENDED/NOSTATE/BLOCKED, it forgets to call qemuDomainObjEndJob. Signed-off-by: Jincheng Miao --- src/qemu/qemu_driver.c |4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) This looks like the fix for https://bugzilla.redhat.com/show_bug.cgi?id=1134154 - thanks for chasing that! This patch fix the part of that bug, but it doesn't touch the race condition: Why the snap->def->state is NOSTATE? It should be RUNNING. The only reasonable explanation is that snapshot object is free()ed. IMHO, the SnapshotObjList should be clocked during snapshot job running. Okay, I see what you are saying; we need to make sure two parallel snapshot operations can't stomp on one another (probably by making them all guarded by the vm job lock). Yes, wrapper the snapshot operations by vm job lock good choice, s/good choice/is a good choice/ and I will check some other functions, and compose a patch for it. I hope to have time to look into a fix before 1.2.8; but as it has been a long-standing issue, it's not a new regression in this release if I miss that goal (my priority today is getting 1.2.8 APIs to be feature-complete). -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] qemu: call endjob in RevertToSnapshot
On 08/27/2014 07:52 PM, Eric Blake wrote: On 08/27/2014 03:20 AM, Jincheng Miao wrote: On 08/27/2014 11:02 AM, Eric Blake wrote: On 08/26/2014 08:10 PM, Jincheng Miao wrote: In qemuDomainRevertToSnapshot(), it will check snap->def->state. But when the state is PMSUSPENDED/NOSTATE/BLOCKED, it forgets to call qemuDomainObjEndJob. Signed-off-by: Jincheng Miao --- src/qemu/qemu_driver.c |4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) This looks like the fix for https://bugzilla.redhat.com/show_bug.cgi?id=1134154 - thanks for chasing that! This patch fix the part of that bug, but it doesn't touch the race condition: Why the snap->def->state is NOSTATE? It should be RUNNING. The only reasonable explanation is that snapshot object is free()ed. IMHO, the SnapshotObjList should be clocked during snapshot job running. Okay, I see what you are saying; we need to make sure two parallel snapshot operations can't stomp on one another (probably by making them all guarded by the vm job lock). Yes, wrapper the snapshot operations by vm job lock good choice, and I will check some other functions, and compose a patch for it. I hope to have time to look into a fix before 1.2.8; but as it has been a long-standing issue, it's not a new regression in this release if I miss that goal (my priority today is getting 1.2.8 APIs to be feature-complete). -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] qemu: call endjob in RevertToSnapshot
On 08/27/2014 03:20 AM, Jincheng Miao wrote: > > On 08/27/2014 11:02 AM, Eric Blake wrote: >> On 08/26/2014 08:10 PM, Jincheng Miao wrote: >>> In qemuDomainRevertToSnapshot(), it will check snap->def->state. >>> But when the state is PMSUSPENDED/NOSTATE/BLOCKED, it forgets to >>> call qemuDomainObjEndJob. >>> >>> Signed-off-by: Jincheng Miao >>> --- >>> src/qemu/qemu_driver.c |4 ++-- >>> 1 files changed, 2 insertions(+), 2 deletions(-) >> This looks like the fix for >> https://bugzilla.redhat.com/show_bug.cgi?id=1134154 - thanks for chasing >> that! > > This patch fix the part of that bug, but it doesn't touch the race > condition: > Why the snap->def->state is NOSTATE? It should be RUNNING. > The only reasonable explanation is that snapshot object is free()ed. > > IMHO, the SnapshotObjList should be clocked during snapshot job running. Okay, I see what you are saying; we need to make sure two parallel snapshot operations can't stomp on one another (probably by making them all guarded by the vm job lock). I hope to have time to look into a fix before 1.2.8; but as it has been a long-standing issue, it's not a new regression in this release if I miss that goal (my priority today is getting 1.2.8 APIs to be feature-complete). -- Eric Blake eblake redhat com+1-919-301-3266 Libvirt virtualization library http://libvirt.org signature.asc Description: OpenPGP digital signature -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] qemu: call endjob in RevertToSnapshot
On 08/27/2014 11:02 AM, Eric Blake wrote: On 08/26/2014 08:10 PM, Jincheng Miao wrote: In qemuDomainRevertToSnapshot(), it will check snap->def->state. But when the state is PMSUSPENDED/NOSTATE/BLOCKED, it forgets to call qemuDomainObjEndJob. Signed-off-by: Jincheng Miao --- src/qemu/qemu_driver.c |4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) This looks like the fix for https://bugzilla.redhat.com/show_bug.cgi?id=1134154 - thanks for chasing that! This patch fix the part of that bug, but it doesn't touch the race condition: Why the snap->def->state is NOSTATE? It should be RUNNING. The only reasonable explanation is that snapshot object is free()ed. IMHO, the SnapshotObjList should be clocked during snapshot job running. ACK, and I'll push soon. -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] qemu: call endjob in RevertToSnapshot
On 08/26/2014 08:10 PM, Jincheng Miao wrote: > In qemuDomainRevertToSnapshot(), it will check snap->def->state. > But when the state is PMSUSPENDED/NOSTATE/BLOCKED, it forgets to > call qemuDomainObjEndJob. > > Signed-off-by: Jincheng Miao > --- > src/qemu/qemu_driver.c |4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) This looks like the fix for https://bugzilla.redhat.com/show_bug.cgi?id=1134154 - thanks for chasing that! ACK, and I'll push soon. -- Eric Blake eblake redhat com+1-919-301-3266 Libvirt virtualization library http://libvirt.org signature.asc Description: OpenPGP digital signature -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
