On 27.07.26 15:05, Denis V. Lunev wrote:
On 7/16/26 13:22, Denis V. Lunev wrote:
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qmp_block_dirty_bitmap_add() and the incoming-migration bitmap loader
both create a persistent bitmap with bdrv_create_dirty_bitmap(), which
always creates it writable, without checking whether the node can
actually be written to. A persistent bitmap added to an already
read-only or inactive node stays writable in memory on a node that
can never store it, and the next global inactivation (migration
completion, save, or any other bdrv_inactivate_all() caller) fails
trying to flush it back:
Lost persistent bitmaps during inactivation of node '<node>': No write access
migration_block_inactivate: bdrv_inactivate_all() failed: -22
Patch 1 rejects this at block-dirty-bitmap-add (and, wrapped in a
transaction, denies the whole transaction). Patch 2 closes the same
hole on the incoming-migration path. Patch 3 fixes a knock-on
regression from patch 1's approach: a bitmap that was rejected from
ever being written can still exist in memory read-only and must
remain removable without requiring write access.
v1 -> v2
* approach changed to deny rather than adopt (Vladimir)
* added patch to add permission check on migration path
* added patch to change permissions check on bitmap drop to more natural
Signed-off-by: Denis V. Lunev <[email protected]>
CC: Eric Blake <[email protected]>
CC: Vladimir Sementsov-Ogievskiy <[email protected]>
CC: John Snow <[email protected]>
CC: Andrey Drobyshev <[email protected]>
Denis V. Lunev (3):
block/monitor: reject persistent bitmap add on a read-only node
migration/block-dirty-bitmap: reject bitmap load onto ro node
block/monitor: allow dropping a bitmap never stored on disk
block/monitor/bitmap-qmp-cmds.c | 19 +++++++----
block/qcow2-bitmap.c | 9 +++++
migration/block-dirty-bitmap.c | 22 +++++++++----
qapi/block-core.json | 4 ++-
tests/qemu-iotests/tests/migrate-bitmaps-test | 33 +++++++++++++++++++
.../tests/migrate-bitmaps-test.out | 4 +--
.../tests/remove-bitmap-from-backing | 29 +++++++++++++++-
.../tests/remove-bitmap-from-backing.out | 22 ++++++++++++-
8 files changed, 124 insertions(+), 18 deletions(-)
Hi, Vladimir!
Will this go through your tree? It is looking like nobody else cares.
Yes, seems so. Thanks, applied to my block branch.
There's still a chance to stop me within 2-3 weeks before 11.2 cycle opens.
--
Best regards,
Vladimir
