[PATCH 0/2] block-backend: Retain permissions after migration

[Hanna Reitz <hreitz@redhat.com>]

Hi,

Peng Liang has reported an issue regarding migration of raw images here:
https://lists.nongnu.org/archive/html/qemu-block/2021-11/msg00673.html

It turns out that after migrating, all permissions are shared when they
weren’t before.  The cause of the problem is that we deliberately delay
restricting the shared permissions until migration is really done (until
the runstate is no longer INMIGRATE) and first share all permissions;
but this causes us to lose the original shared permission mask and
overwrites it with BLK_PERM_ALL, so once we do try to restrict the
shared permissions, we only again share them all.

Fix this by saving the set of shared permissions through the first
blk_perm_set() call that shares all; and add a regression test.


I don’t believe we have to fix this in 6.2, because I think this bug has
existed for four years now.  (I.e. it isn’t critical, and it’s no
regression.)


Hanna Reitz (2):
  block-backend: Retain permissions after migration
  iotests/migration-permissions: New test

 block/block-backend.c                         |  11 ++
 .../qemu-iotests/tests/migration-permissions  | 101 ++++++++++++++++++
 .../tests/migration-permissions.out           |   5 +
 3 files changed, 117 insertions(+)
 create mode 100755 tests/qemu-iotests/tests/migration-permissions
 create mode 100644 tests/qemu-iotests/tests/migration-permissions.out

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2.33.1