luks: Allow share-rw=on

Format drivers such as qcow2 don't allow sharing the same image between
two QEMU instances in order to prevent image corruptions, because of
metadata cache. LUKS driver don't modify metadata except for when
creating image, so it is safe to relax the permission. This makes
share-rw=on property work on virtual devices.

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2018-08-14 15:25:51 +08:00 committed by Kevin Wolf
parent 25b8e4db7f
commit 497da8236a

View file

@ -627,7 +627,9 @@ BlockDriver bdrv_crypto_luks = {
.bdrv_probe = block_crypto_probe_luks,
.bdrv_open = block_crypto_open_luks,
.bdrv_close = block_crypto_close,
.bdrv_child_perm = bdrv_format_default_perms,
/* This driver doesn't modify LUKS metadata except when creating image.
* Allow share-rw=on as a special case. */
.bdrv_child_perm = bdrv_filter_default_perms,
.bdrv_co_create = block_crypto_co_create_luks,
.bdrv_co_create_opts = block_crypto_co_create_opts_luks,
.bdrv_co_truncate = block_crypto_co_truncate,