Right now, bdrv_format_default_perms() is used by format parents
(generally). We want to switch to a model where most parents use a
single BdrvChildClass, which then decides the permissions based on the
child role. To do so, we have to split bdrv_format_default_perms() into
separate functions for each such role.
Signed-off-by: Max Reitz
Reviewed-by: Eric Blake
---
block.c | 62 +
1 file changed, 40 insertions(+), 22 deletions(-)
diff --git a/block.c b/block.c
index 982785b15a..8b97412cbc 100644
--- a/block.c
+++ b/block.c
@@ -2302,6 +2302,44 @@ void bdrv_filter_default_perms(BlockDriverState *bs,
BdrvChild *c,
*nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
}
+static void bdrv_default_perms_for_backing(BlockDriverState *bs, BdrvChild *c,
+ const BdrvChildClass *child_class,
+ BdrvChildRole role,
+ BlockReopenQueue *reopen_queue,
+ uint64_t perm, uint64_t shared,
+ uint64_t *nperm, uint64_t *nshared)
+{
+assert(child_class == &child_backing ||
+ (child_class == &child_of_bds && (role & BDRV_CHILD_COW)));
+
+/*
+ * We want consistent read from backing files if the parent needs it.
+ * No other operations are performed on backing files.
+ */
+perm &= BLK_PERM_CONSISTENT_READ;
+
+/*
+ * If the parent can deal with changing data, we're okay with a
+ * writable and resizable backing file.
+ * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too?
+ */
+if (shared & BLK_PERM_WRITE) {
+shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
+} else {
+shared = 0;
+}
+
+shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
+ BLK_PERM_WRITE_UNCHANGED;
+
+if (bs->open_flags & BDRV_O_INACTIVE) {
+shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+}
+
+*nperm = perm;
+*nshared = shared;
+}
+
void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
const BdrvChildClass *child_class,
BdrvChildRole role,
@@ -2339,28 +2377,8 @@ void bdrv_format_default_perms(BlockDriverState *bs,
BdrvChild *c,
*nperm = perm;
*nshared = shared;
} else {
-/* We want consistent read from backing files if the parent needs it.
- * No other operations are performed on backing files. */
-perm &= BLK_PERM_CONSISTENT_READ;
-
-/* If the parent can deal with changing data, we're okay with a
- * writable and resizable backing file. */
-/* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
-if (shared & BLK_PERM_WRITE) {
-shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
-} else {
-shared = 0;
-}
-
-shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
- BLK_PERM_WRITE_UNCHANGED;
-
-if (bs->open_flags & BDRV_O_INACTIVE) {
-shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
-}
-
-*nperm = perm;
-*nshared = shared;
+bdrv_default_perms_for_backing(bs, c, child_class, role, reopen_queue,
+ perm, shared, nperm, nshared);
}
}
--
2.24.1
