[PATCH 2/2] block: assert that permission commit sets same permissions

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

On permission update commit we must set same permissions as on _check_.
Let's add assertions. Next step may be to drop permission parameters
from _set_.

Note that prior to previous commit, fixing bdrv_drop_intermediate(),
new assertion in bdrv_child_set_perm() crashes on iotests 30 and 40.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index bd9f4e534b..0f4da59a6c 100644
--- a/block.c
+++ b/block.c
@@ -2105,9 +2105,10 @@ static void bdrv_abort_perm_update(BlockDriverState *bs)
     }
 }
 
-static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
-                          uint64_t cumulative_shared_perms)
+static void bdrv_set_perm(BlockDriverState *bs, uint64_t _cumulative_perms,
+                          uint64_t _cumulative_shared_perms)
 {
+    uint64_t cumulative_perms, cumulative_shared_perms;
     BlockDriver *drv = bs->drv;
     BdrvChild *c;
 
@@ -2115,6 +2116,10 @@ static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
         return;
     }
 
+    bdrv_get_cumulative_perm(bs, &cumulative_perms, &cumulative_shared_perms);
+    assert(_cumulative_perms == cumulative_perms);
+    assert(_cumulative_shared_perms == cumulative_shared_perms);
+
     /* Update this node */
     if (drv->bdrv_set_perm) {
         drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms);
@@ -2301,6 +2306,8 @@ static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared)
 
     c->has_backup_perm = false;
 
+    assert(c->perm == perm);
+    assert(c->shared_perm == shared);
     c->perm = perm;
     c->shared_perm = shared;
 
-- 
2.21.3