Disk operations can take ages to finish. Therefore users might want to abort such job, e.g. because host is going down for maintenance. This patch set is trying to allow this kind of behaviour. The inspiration was taken from qemu driver.
How it works: An API that is known to run for a long time, e.g. volume allocation, wiping, have to find a pool which volume belongs to. If the pool was found it is locked. During this time the storage driver is locked. Now the API is preparing for taking the operation. Ideally, it would be sufficient to have only volume locked, but it requires far more changes to code. Just before the API is about to take the long term action, storageBeginJob[WithPool] is called. This wait on a condition specific for a volume. Similar to QEMU driver, wait is limited in time. Timeout is set to 30 seconds. Upon successful job acquire, a counter in the pool is incremented so the pool is prevented from destroy, undef; Then the pool is unlocked. After API finishes it's work, it calls storageEndJob[WithPool] which reset job structure in the volume, re-locks the pool, decrement the counter and broadcasts on the condition. Meanwhile, if the long term action is done internally, it should be done in a cycle so we can check if job abort wasn't signalized. If it is done by external program, we can virCommandAbort() it. Several improvements can be made, but I think this is good for start. NB, I've implemented job aborting for the both APIs using streams, however wasn't very successful with aborting a stream from the daemon site. Michal Privoznik (4): storage: Introduce virStorageVolAbortJob virsh: Expose virStorageVolAbortJob storage: Implement jobs for storage driver storage: Implement virStorageVolAbortJob include/libvirt/libvirt.h.in | 3 + src/conf/storage_conf.c | 12 ++ src/conf/storage_conf.h | 29 +++- src/driver.h | 5 + src/libvirt.c | 49 +++++ src/libvirt_private.syms | 4 + src/libvirt_public.syms | 1 + src/remote/remote_driver.c | 1 + src/remote/remote_protocol.x | 8 +- src/remote_protocol-structs | 5 + src/storage/storage_backend.c | 53 +++--- src/storage/storage_backend_fs.c | 8 +- src/storage/storage_driver.c | 408 ++++++++++++++++++++++++++++++-------- src/storage/storage_driver.h | 7 + tools/virsh.c | 39 ++++ 15 files changed, 516 insertions(+), 116 deletions(-) -- 1.7.8.5 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
