Am 27.11.2020 um 15:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
Split out non-recursive parts, and refactor as block graph transaction
action.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
block.c | 79 ++++++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 59 insertions(+), 20 deletions(-)
diff --git a/block.c b/block.c
index a756f3e8ad..7267b4a3e9 100644
--- a/block.c
+++ b/block.c
@@ -48,6 +48,7 @@
#include "qemu/timer.h"
#include "qemu/cutils.h"
#include "qemu/id.h"
+#include "qemu/transactions.h"
#include "block/coroutines.h"
#ifdef CONFIG_BSD
@@ -2033,6 +2034,61 @@ static void bdrv_child_perm(BlockDriverState *bs,
BlockDriverState *child_bs,
}
}
+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()
s/NUll/NULL/
+ * instead.
+ */
+static void bdrv_child_set_perm_safe(BdrvChild *c, uint64_t perm,
+ uint64_t shared, GSList **tran)
+{
+ if (!c->has_backup_perm) {
+ c->has_backup_perm = true;
+ c->backup_perm = c->perm;
+ c->backup_shared_perm = c->shared_perm;
+ }
This is the obvious refactoring at this point, and it's fine as such.
However, when you start to actually use tran (and in new places), it
means that I have to check that we can never end up here recursively
with a different tran.