Merge remote-tracking branch 'remotes/ericb/tags/pull-bitmaps-2021-02-12' into staging

bitmaps patches for 2021-02-12

- add 'transform' member to manipulate bitmaps across migration
- work towards better error handling during bdrv_open

# gpg: Signature made Fri 12 Feb 2021 23:19:39 GMT
# gpg:                using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-bitmaps-2021-02-12:
  block: use return status of bdrv_append()
  block: return status from bdrv_append and friends
  qemu-iotests: 300: Add test case for modifying persistence of bitmap
  migration: dirty-bitmap: Allow control of bitmap persistence
  migration: dirty-bitmap: Use struct for alias map inner members

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 39 insertions, 25 deletions

diff --git a/block.c b/block.c
index 4e52b1c588..c682c3e3b9 100644
--- a/block.c
+++ b/block.c
@@ -2827,14 +2827,15 @@ static BdrvChildRole bdrv_backing_role(BlockDriverState *bs)
  * Sets the bs->backing link of a BDS. A new reference is created; callers
  * which don't need their own reference any more must call bdrv_unref().
  */
-void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
-                         Error **errp)
+int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
+                        Error **errp)
 {
+    int ret = 0;
     bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
         bdrv_inherits_from_recursive(backing_hd, bs);
 
     if (bdrv_is_backing_chain_frozen(bs, child_bs(bs->backing), errp)) {
-        return;
+        return -EPERM;
     }
 
     if (backing_hd) {
@@ -2853,15 +2854,22 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
 
     bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds,
                                     bdrv_backing_role(bs), errp);
+    if (!bs->backing) {
+        ret = -EPERM;
+        goto out;
+    }
+
     /* If backing_hd was already part of bs's backing chain, and
      * inherits_from pointed recursively to bs then let's update it to
      * point directly to bs (else it will become NULL). */
-    if (bs->backing && update_inherits_from) {
+    if (update_inherits_from) {
         backing_hd->inherits_from = bs;
     }
 
 out:
     bdrv_refresh_limits(bs, NULL);
+
+    return ret;
 }
 
 /*
@@ -3110,7 +3118,6 @@ static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
     int64_t total_size;
     QemuOpts *opts = NULL;
     BlockDriverState *bs_snapshot = NULL;
-    Error *local_err = NULL;
     int ret;
 
     /* if snapshot, we create a temporary backing file and open it
@@ -3157,9 +3164,8 @@ static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs,
      * order to be able to return one, we have to increase
      * bs_snapshot's refcount here */
     bdrv_ref(bs_snapshot);
-    bdrv_append(bs_snapshot, bs, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    ret = bdrv_append(bs_snapshot, bs, errp);
+    if (ret < 0) {
         bs_snapshot = NULL;
         goto out;
     }
@@ -4532,9 +4538,9 @@ static bool should_update_child(BdrvChild *c, BlockDriverState *to)
  * With auto_skip=false the error is returned if from has a parent which should
  * not be updated.
  */
-static void bdrv_replace_node_common(BlockDriverState *from,
-                                     BlockDriverState *to,
-                                     bool auto_skip, Error **errp)
+static int bdrv_replace_node_common(BlockDriverState *from,
+                                    BlockDriverState *to,
+                                    bool auto_skip, Error **errp)
 {
     BdrvChild *c, *next;
     GSList *list = NULL, *p;
@@ -4556,11 +4562,13 @@ static void bdrv_replace_node_common(BlockDriverState *from,
             if (auto_skip) {
                 continue;
             }
+            ret = -EINVAL;
             error_setg(errp, "Should not change '%s' link to '%s'",
                        c->name, from->node_name);
             goto out;
         }
         if (c->frozen) {
+            ret = -EPERM;
             error_setg(errp, "Cannot change '%s' link to '%s'",
                        c->name, from->node_name);
             goto out;
@@ -4591,14 +4599,18 @@ static void bdrv_replace_node_common(BlockDriverState *from,
 
     bdrv_set_perm(to);
 
+    ret = 0;
+
 out:
     g_slist_free(list);
     bdrv_drained_end(from);
     bdrv_unref(from);
+
+    return ret;
 }
 
-void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
-                       Error **errp)
+int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
+                      Error **errp)
 {
     return bdrv_replace_node_common(from, to, true, errp);
 }
@@ -4619,28 +4631,30 @@ void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
  * parents of bs_top after bdrv_append() returns. If the caller needs to keep a
  * reference of its own, it must call bdrv_ref().
  */
-void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
-                 Error **errp)
+int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
+                Error **errp)
 {
-    Error *local_err = NULL;
-
-    bdrv_set_backing_hd(bs_new, bs_top, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    int ret = bdrv_set_backing_hd(bs_new, bs_top, errp);
+    if (ret < 0) {
         goto out;
     }
 
-    bdrv_replace_node(bs_top, bs_new, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    ret = bdrv_replace_node(bs_top, bs_new, errp);
+    if (ret < 0) {
         bdrv_set_backing_hd(bs_new, NULL, &error_abort);
         goto out;
     }
 
-    /* bs_new is now referenced by its new parents, we don't need the
-     * additional reference any more. */
+    ret = 0;
+
 out:
+    /*
+     * bs_new is now referenced by its new parents, we don't need the
+     * additional reference any more.
+     */
     bdrv_unref(bs_new);
+
+    return ret;
 }
 
 static void bdrv_delete(BlockDriverState *bs)