i386: Document when features can be added to kvm_default_props

[mirror_qemu.git] / block.c

diff --git a/block.c b/block.c
index df8fa6003c2dbf5f03e76a616d2fb32d0b60df20..0dc97281dcfd09c964720c93d5d27e0940bb313d 100644 (file)
--- 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
@@ -41,7 +42,6 @@
 #include "qapi/qobject-output-visitor.h"
 #include "qapi/qapi-visit-block-core.h"
 #include "sysemu/block-backend.h"
-#include "sysemu/sysemu.h"
 #include "qemu/notify.h"
 #include "qemu/option.h"
 #include "qemu/coroutine.h"
@@ -400,7 +400,6 @@ BlockDriverState *bdrv_new(void)
     for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
         QLIST_INIT(&bs->op_blockers[i]);
     }
-    notifier_with_return_list_init(&bs->before_write_notifiers);
     qemu_co_mutex_init(&bs->reqs_lock);
     qemu_mutex_init(&bs->dirty_bitmap_mutex);
     bs->refcnt = 1;
@@ -2270,22 +2269,18 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs,
 }
 
 /*
- * 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().
+ * Refresh permissions in @bs subtree. The function is intended to be called
+ * after some graph modification that was done without permission update.
  */
-static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
-                                uint64_t cumulative_perms,
-                                uint64_t cumulative_shared_perms,
-                                Transaction *tran, Error **errp)
+static int bdrv_node_refresh_perm(BlockDriverState *bs, BlockReopenQueue *q,
+                                  Transaction *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)) &&
@@ -2294,15 +2289,8 @@ 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, "Read-only block node '%s' cannot support "
+                       "read-write users", bdrv_get_node_name(bs));
         }
 
         return -EPERM;
@@ -2358,7 +2346,6 @@ static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q,
                                    Transaction *tran, Error **errp)
 {
     int ret;
-    uint64_t cumulative_perms, cumulative_shared_perms;
     BlockDriverState *bs;
 
     for ( ; list; list = list->next) {
@@ -2368,12 +2355,7 @@ 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;
         }
@@ -2934,13 +2916,14 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
                                    child_role, perm, shared_perm, opaque,
                                    &child, tran, errp);
     if (ret < 0) {
-        bdrv_unref(child_bs);
-        return NULL;
+        assert(child == NULL);
+        goto out;
     }
 
     ret = bdrv_refresh_perms(child_bs, errp);
-    tran_finalize(tran, ret);
 
+out:
+    tran_finalize(tran, ret);
     bdrv_unref(child_bs);
     return child;
 }
@@ -4067,7 +4050,7 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
         ret = bdrv_flush(bs_entry->state.bs);
         if (ret < 0) {
             error_setg_errno(errp, -ret, "Error flushing drive");
-            goto cleanup;
+            goto abort;
         }
     }