block: consistently use bdrv_is_read_only()

It's better to use accessor function instead of bs->read_only directly.
In some places use bdrv_is_writable() instead of
checking both BDRV_O_RDWR set and BDRV_O_INACTIVE not set.

In bdrv_open_common() it's a bit strange to add one more variable, but
we are going to drop bs->read_only in the next patch, so new ro local
variable substitutes it here.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210527154056.70294-2-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index 39b91ef..ee4530c 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1723,8 +1723,7 @@
 
     /* Clear unknown autoclear feature bits */
     update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK;
-    update_header =
-        update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE);
+    update_header = update_header && bdrv_is_writable(bs);
     if (update_header) {
         s->autoclear_features &= QCOW2_AUTOCLEAR_MASK;
     }
@@ -1811,7 +1810,7 @@
     bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
 
     /* Repair image if dirty */
-    if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only &&
+    if (!(flags & BDRV_O_CHECK) && bdrv_is_writable(bs) &&
         (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
         BdrvCheckResult result = {0};