[PATCH v2 36/36] block: refactor bdrv_node_check_perm()

[Vladimir Sementsov-Ogievskiy]

Now, bdrv_node_check_perm() is called only with fresh cumulative
permissions, so its actually "refresh_perm".

Move permission calculation to the function. Also, drop unreachable
error message.

Add also Virtuozzo copyright, as big work is done at this point.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block.c | 38 +++++++++-----------------------------
 1 file changed, 9 insertions(+), 29 deletions(-)

diff --git a/block.c b/block.c
index 20b1cf59f7..576b145cbf 100644
--- a/block.c
+++ b/block.c
@@ -2,6 +2,7 @@
  * QEMU System Emulator block driver
  *
  * Copyright (c) 2003 Fabrice Bellard
+ * Copyright (c) 2020 Virtuozzo International GmbH.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to 
deal
@@ -2204,23 +2205,15 @@ static void bdrv_replace_child(BdrvChild *child, 
BlockDriverState *new_bs,
     /* old_bs reference is transparently moved from @child to @s */
 }
 
-/*
- * Check whether permissions on this node can be changed in a way that
- * @cumulative_perms and @cumulative_shared_perms are the new cumulative
- * permissions of all its parents. This involves checking whether all necessary
- * permission changes to child nodes can be performed.
- *
- * A call to this function must always be followed by a call to bdrv_set_perm()
- * or bdrv_abort_perm_update().
- */
-static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
-                                uint64_t cumulative_perms,
-                                uint64_t cumulative_shared_perms,
-                                GSList **tran, Error **errp)
+static int bdrv_node_refresh_perm(BlockDriverState *bs, BlockReopenQueue *q,
+                                  GSList **tran, Error **errp)
 {
     BlockDriver *drv = bs->drv;
     BdrvChild *c;
     int ret;
+    uint64_t cumulative_perms, cumulative_shared_perms;
+
+    bdrv_get_cumulative_perm(bs, &cumulative_perms, &cumulative_shared_perms);
 
     /* Write permissions never work with read-only images */
     if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) &&
@@ -2229,15 +2222,8 @@ static int bdrv_node_check_perm(BlockDriverState *bs, 
BlockReopenQueue *q,
         if (!bdrv_is_writable_after_reopen(bs, NULL)) {
             error_setg(errp, "Block node is read-only");
         } else {
-            uint64_t current_perms, current_shared;
-            bdrv_get_cumulative_perm(bs, &current_perms, &current_shared);
-            if (current_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) {
-                error_setg(errp, "Cannot make block node read-only, there is "
-                           "a writer on it");
-            } else {
-                error_setg(errp, "Cannot make block node read-only and create "
-                           "a writer on it");
-            }
+            error_setg(errp, "Cannot make block node read-only, there is "
+                       "a writer on it");
         }
 
         return -EPERM;
@@ -2293,7 +2279,6 @@ static int bdrv_list_refresh_perms(GSList *list, 
BlockReopenQueue *q,
                                    GSList **tran, Error **errp)
 {
     int ret;
-    uint64_t cumulative_perms, cumulative_shared_perms;
     BlockDriverState *bs;
 
     for ( ; list; list = list->next) {
@@ -2303,12 +2288,7 @@ static int bdrv_list_refresh_perms(GSList *list, 
BlockReopenQueue *q,
             return -EINVAL;
         }
 
-        bdrv_get_cumulative_perm(bs, &cumulative_perms,
-                                 &cumulative_shared_perms);
-
-        ret = bdrv_node_check_perm(bs, q, cumulative_perms,
-                                   cumulative_shared_perms,
-                                   tran, errp);
+        ret = bdrv_node_refresh_perm(bs, q, tran, errp);
         if (ret < 0) {
             return ret;
         }
-- 
2.21.3