block: Distinguish paths in *_format_default_perms

bdrv_format_default_perms() has one code path for backing files, and one
for storage files.  We want to pull them out into their own functions,
so make sure they are completely distinct before so the next patches
will be a bit cleaner.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200513110544.176672-16-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

@@ -2497,6 +2497,13 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
             perm |= BLK_PERM_CONSISTENT_READ;
         }
         shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
+
+        if (bs->open_flags & BDRV_O_INACTIVE) {
+            shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+        }
+
+        *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. */
@@ -2513,14 +2520,14 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
 
         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;
-    }
+        if (bs->open_flags & BDRV_O_INACTIVE) {
+            shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+        }
 
-    *nperm = perm;
-    *nshared = shared;
+        *nperm = perm;
+        *nshared = shared;
+    }
 }
 
 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm)