@@ -190,6 +190,7 @@ static void blk_root_activate(BdrvChild *child, Error **errp)
{
BlockBackend *blk = child->opaque;
Error *local_err = NULL;
+ uint64_t saved_shared_perm;
if (!blk->disable_perm) {
return;
@@ -197,12 +198,22 @@ static void blk_root_activate(BdrvChild *child, Error **errp)
blk->disable_perm = false;
+ /*
+ * blk->shared_perm contains the permissions we want to share once
+ * migration is really completely done. For now, we need to share
+ * all; but we also need to retain blk->shared_perm, which is
+ * overwritten by a successful blk_set_perm() call. Save it and
+ * restore it below.
+ */
+ saved_shared_perm = blk->shared_perm;
+
blk_set_perm(blk, blk->perm, BLK_PERM_ALL, &local_err);
if (local_err) {
error_propagate(errp, local_err);
blk->disable_perm = true;
return;
}
+ blk->shared_perm = saved_shared_perm;
if (runstate_check(RUN_STATE_INMIGRATE)) {
/* Activation can happen when migration process is still active, for
After migration, the permissions the guest device wants to impose on its BlockBackend are stored in blk->perm and blk->shared_perm. In blk_root_activate(), we take our permissions, but keep all shared permissions open by calling `blk_set_perm(blk->perm, BLK_PERM_ALL)`. Only afterwards (immediately or later, depending on the runstate) do we restrict the shared permissions by calling `blk_set_perm(blk->perm, blk->shared_perm)`. Unfortunately, our first call with shared_perm=BLK_PERM_ALL has overwritten blk->shared_perm to be BLK_PERM_ALL, so this is a no-op and the set of shared permissions is not restricted. Fix this bug by saving the set of shared permissions before invoking blk_set_perm() with BLK_PERM_ALL and restoring it afterwards. Fixes: 5f7772c4d0cf32f4e779fcd5a69ae4dae24aeebf ("block-backend: Defer shared_perm tightening migration completion") Reported-by: Peng Liang <liangpeng10@huawei.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20211125135317.186576-2-hreitz@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Peng Liang <liangpeng10@huawei.com> --- block/block-backend.c | 11 +++++++++++ 1 file changed, 11 insertions(+)