*nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
}
+static void bdrv_default_perms_for_cow(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,
*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_cow(bs, c, child_class, role, reopen_queue,
+ perm, shared, nperm, nshared);
}
}