This series adds a mechanism that allows the user or management tool to manually activate and inactivate block nodes instead of fully relying on the automatic management in the migration code.
One case where this is needed is for migration with shared storage and devices backed by qemu-storage-daemon, which as an external process is not involved in the VM migration. Management tools can manually orchestrate the handover in this scenario. The new qemu-iotests case qsd-migrate demonstrates this. There are other cases without qemu-storage-daemon where manual management is necessary. For example, after migration, the destination VM only activates images on 'cont', but after migrating a paused VM, the user may want to perform operations on a block node while the VM is still paused. This series adds support for block exports on an inactive node (needed for shared storage migration with qemu-storage-daemon) only to NBD. Adding it to other export types will be done in a future series. v2: - Added a comprehensive test case that tests how inactive nodes interoperate with many operations - Added a couple of fixes for bugs uncovered by the tests (that would usually lead to crashes when an unsupported operation is performed on inactive nodes) - Added 'active' status to query-block information Kevin Wolf (15): block: Add 'active' field to BlockDeviceInfo block: Inactivate external snapshot overlays when necessary migration/block-active: Remove global active flag block: Don't attach inactive child to active node block: Allow inactivating already inactive nodes block: Fix crash on block_resize on inactive node block: Add option to create inactive nodes block: Add blockdev-set-active QMP command block: Support inactive nodes in blk_insert_bs() block/export: Don't ignore image activation error in blk_exp_add() block/export: Add option to allow export of inactive nodes nbd/server: Support inactive nodes iotests: Add filter_qtest() iotests: Add qsd-migrate case iotests: Add (NBD-based) tests for inactive nodes qapi/block-core.json | 44 ++- qapi/block-export.json | 10 +- include/block/block-common.h | 1 + include/block/block-global-state.h | 6 + include/block/export.h | 3 + migration/migration.h | 3 - block.c | 62 +++- block/block-backend.c | 16 +- block/export/export.c | 29 +- block/monitor/block-hmp-cmds.c | 5 +- block/qapi.c | 1 + blockdev.c | 48 +++ migration/block-active.c | 46 --- migration/migration.c | 8 - nbd/server.c | 17 + tests/qemu-iotests/iotests.py | 8 + tests/qemu-iotests/041 | 4 +- tests/qemu-iotests/165 | 4 +- tests/qemu-iotests/184.out | 2 + tests/qemu-iotests/191.out | 16 + tests/qemu-iotests/273.out | 5 + tests/qemu-iotests/tests/copy-before-write | 3 +- tests/qemu-iotests/tests/inactive-node-nbd | 303 ++++++++++++++++++ .../qemu-iotests/tests/inactive-node-nbd.out | 239 ++++++++++++++ tests/qemu-iotests/tests/migrate-bitmaps-test | 7 +- tests/qemu-iotests/tests/qsd-migrate | 132 ++++++++ tests/qemu-iotests/tests/qsd-migrate.out | 51 +++ 27 files changed, 986 insertions(+), 87 deletions(-) create mode 100755 tests/qemu-iotests/tests/inactive-node-nbd create mode 100644 tests/qemu-iotests/tests/inactive-node-nbd.out create mode 100755 tests/qemu-iotests/tests/qsd-migrate create mode 100644 tests/qemu-iotests/tests/qsd-migrate.out -- 2.48.1
