block: refactor bdrv_child* permission functions
Split out non-recursive parts, and refactor as block graph transaction
action.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210428151804.439460-11-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index fd621f0..0ee0c2f 100644
--- a/block.c
+++ b/block.c
@@ -49,6 +49,7 @@
#include "qemu/timer.h"
#include "qemu/cutils.h"
#include "qemu/id.h"
+#include "qemu/transactions.h"
#include "block/coroutines.h"
#ifdef CONFIG_BSD
@@ -2093,6 +2094,61 @@
}
}
+static void bdrv_child_set_perm_commit(void *opaque)
+{
+ BdrvChild *c = opaque;
+
+ c->has_backup_perm = false;
+}
+
+static void bdrv_child_set_perm_abort(void *opaque)
+{
+ BdrvChild *c = opaque;
+ /*
+ * We may have child->has_backup_perm unset at this point, as in case of
+ * _check_ stage of permission update failure we may _check_ not the whole
+ * subtree. Still, _abort_ is called on the whole subtree anyway.
+ */
+ if (c->has_backup_perm) {
+ c->perm = c->backup_perm;
+ c->shared_perm = c->backup_shared_perm;
+ c->has_backup_perm = false;
+ }
+}
+
+static TransactionActionDrv bdrv_child_set_pem_drv = {
+ .abort = bdrv_child_set_perm_abort,
+ .commit = bdrv_child_set_perm_commit,
+};
+
+/*
+ * With tran=NULL needs to be followed by direct call to either
+ * bdrv_child_set_perm_commit() or bdrv_child_set_perm_abort().
+ *
+ * With non-NULL tran needs to be followed by tran_abort() or tran_commit()
+ * instead.
+ */
+static void bdrv_child_set_perm_safe(BdrvChild *c, uint64_t perm,
+ uint64_t shared, Transaction *tran)
+{
+ if (!c->has_backup_perm) {
+ c->has_backup_perm = true;
+ c->backup_perm = c->perm;
+ c->backup_shared_perm = c->shared_perm;
+ }
+ /*
+ * Note: it's OK if c->has_backup_perm was already set, as we can find the
+ * same c twice during check_perm procedure
+ */
+
+ c->perm = perm;
+ c->shared_perm = shared;
+
+ if (tran) {
+ tran_add(tran, &bdrv_child_set_pem_drv, c);
+ }
+}
+
/*
* Check whether permissions on this node can be changed in a way that
* @cumulative_perms and @cumulative_shared_perms are the new cumulative
@@ -2358,37 +2414,20 @@
return ret;
}
- if (!c->has_backup_perm) {
- c->has_backup_perm = true;
- c->backup_perm = c->perm;
- c->backup_shared_perm = c->shared_perm;
- }
- /*
- * Note: it's OK if c->has_backup_perm was already set, as we can find the
- * same child twice during check_perm procedure
- */
-
- c->perm = perm;
- c->shared_perm = shared;
+ bdrv_child_set_perm_safe(c, perm, shared, NULL);
return 0;
}
static void bdrv_child_set_perm(BdrvChild *c)
{
- c->has_backup_perm = false;
-
+ bdrv_child_set_perm_commit(c);
bdrv_set_perm(c->bs);
}
static void bdrv_child_abort_perm_update(BdrvChild *c)
{
- if (c->has_backup_perm) {
- c->perm = c->backup_perm;
- c->shared_perm = c->backup_shared_perm;
- c->has_backup_perm = false;
- }
-
+ bdrv_child_set_perm_abort(c);
bdrv_abort_perm_update(c->bs);
}
