block: Simplify bdrv_filter_default_perms()

The same change as commit 2b23f28639 ('block/copy-on-read: Fix
permissions for inactive node') made for the copy-on-read driver can be
made for bdrv_filter_default_perms(): Retaining the old permissions from
the BdrvChild if it is given complicates things unnecessarily when in
the end this only means that the options set in the c == NULL case (i.e.
during child creation) are retained.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

diff --git a/block.c b/block.c
index cbd8da5f3bd4e43f651de655b4151b8c4a890bef..6db8ecd62b189545a669e7f33c29565f486501ce 100644 (file)
--- a/block.c
+++ b/block.c
@@ -2168,16 +2168,8 @@ void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared)
 {
-    if (c == NULL) {
-        *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
-        *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
-        return;
-    }
-
-    *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) |
-             (c->perm & DEFAULT_PERM_UNCHANGED);
-    *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) |
-               (c->shared_perm & DEFAULT_PERM_UNCHANGED);
+    *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
+    *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
 }
 
 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,