Blame SOURCES/libvirt-qemu-checkpoint-Introduce-support-for-deleting-checkpoints-accross-snapshots.patch

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From 30377cd627a919e51cc4bb60a8a57e94e73f016c Mon Sep 17 00:00:00 2001
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Message-Id: <30377cd627a919e51cc4bb60a8a57e94e73f016c@dist-git>
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From: Peter Krempa <pkrempa@redhat.com>
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Date: Tue, 4 Feb 2020 15:08:12 +0100
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Subject: [PATCH] qemu: checkpoint: Introduce support for deleting checkpoints
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 accross snapshots
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Allow deleting of checkpoints when snapshots were created along. The
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code tracks and modifies the checkpoint list so that backups can still
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be taken with such a backing chain. This unfortunately requires to
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rename few bitmaps (by copying and deleting them) in some cases.
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Signed-off-by: Peter Krempa <pkrempa@redhat.com>
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Reviewed-by: Ján Tomko <jtomko@redhat.com>
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(cherry picked from commit 30bc426071c0f5957af01181c063cd68ade97899)
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https://bugzilla.redhat.com/show_bug.cgi?id=1207659
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Message-Id: <e9f416811658b2ba03968ae5fca783b7fb7649f7.1580824112.git.pkrempa@redhat.com>
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Reviewed-by: Ján Tomko <jtomko@redhat.com>
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---
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 src/qemu/qemu_checkpoint.c | 112 ++++++++++++++++++++++++++++---------
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 src/qemu/qemu_checkpoint.h |   5 +-
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 tests/qemublocktest.c      |  34 +++++++----
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 3 files changed, 111 insertions(+), 40 deletions(-)
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diff --git a/src/qemu/qemu_checkpoint.c b/src/qemu/qemu_checkpoint.c
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index e75cdd0458..55061bbf76 100644
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--- a/src/qemu/qemu_checkpoint.c
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+++ b/src/qemu/qemu_checkpoint.c
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@@ -24,6 +24,7 @@
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 #include "qemu_capabilities.h"
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 #include "qemu_monitor.h"
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 #include "qemu_domain.h"
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+#include "qemu_block.h"
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 #include "virerror.h"
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 #include "virlog.h"
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@@ -150,39 +151,92 @@ qemuCheckpointFindActiveDiskInParent(virDomainObjPtr vm,
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 int
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 qemuCheckpointDiscardDiskBitmaps(virStorageSourcePtr src,
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+                                 virHashTablePtr blockNamedNodeData,
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                                  const char *delbitmap,
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                                  const char *parentbitmap,
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-                                 bool chkcurrent,
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-                                 virJSONValuePtr actions)
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+                                 virJSONValuePtr actions,
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+                                 const char *diskdst)
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 {
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-    if (parentbitmap) {
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-        g_autoptr(virJSONValue) arr = NULL;
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+    virStorageSourcePtr n = src;
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-        if (!(arr = virJSONValueNewArray()))
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-            return -1;
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+    /* find the backing chain entry with bitmap named '@delbitmap' */
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+    while (n) {
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+        qemuBlockNamedNodeDataBitmapPtr tmp;
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-        if (qemuMonitorTransactionBitmapMergeSourceAddBitmap(arr,
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-                                                             src->nodeformat,
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-                                                             delbitmap) < 0)
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-            return -1;
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+        if ((tmp = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
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+                                                         n, delbitmap))) {
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+            break;
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+        }
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-        if (chkcurrent) {
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-            if (qemuMonitorTransactionBitmapEnable(actions,
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-                                                   src->nodeformat,
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-                                                   parentbitmap) < 0)
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+        n = n->backingStore;
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+    }
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+
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+    if (!n) {
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+        virReportError(VIR_ERR_INTERNAL_ERROR,
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+                       _("bitmap '%s' not found in backing chain of '%s'"),
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+                       delbitmap, diskdst);
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+        return -1;
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+    }
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+
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+    while (n) {
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+        qemuBlockNamedNodeDataBitmapPtr srcbitmap;
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+
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+        if (!(srcbitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
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+                                                                n, delbitmap)))
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+            break;
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+
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+        /* For the actual checkpoint deletion we will merge any bitmap into the
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+         * bitmap of the parent checkpoint (@parentbitmap) or for any image
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+         * where the parent checkpoint bitmap is not present we must rename
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+         * the bitmap of the deleted checkpoint into the bitmap of the parent
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+         * checkpoint as qemu can't currently take the allocation map and turn
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+         * it into a bitmap and thus we wouldn't be able to do a backup. */
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+        if (parentbitmap) {
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+            qemuBlockNamedNodeDataBitmapPtr dstbitmap;
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+            g_autoptr(virJSONValue) arr = NULL;
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+
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+            dstbitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
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+                                                              n, parentbitmap);
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+
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+            if (dstbitmap) {
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+                if (srcbitmap->recording && !dstbitmap->recording) {
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+                    if (qemuMonitorTransactionBitmapEnable(actions,
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+                                                           n->nodeformat,
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+                                                           dstbitmap->name) < 0)
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+                        return -1;
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+                }
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+
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+            } else {
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+                if (qemuMonitorTransactionBitmapAdd(actions,
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+                                                    n->nodeformat,
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+                                                    parentbitmap,
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+                                                    true,
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+                                                    !srcbitmap->recording,
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+                                                    srcbitmap->granularity) < 0)
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+                    return -1;
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+            }
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+
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+            if (!(arr = virJSONValueNewArray()))
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+                return -1;
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+
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+            if (qemuMonitorTransactionBitmapMergeSourceAddBitmap(arr,
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+                                                                 n->nodeformat,
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+                                                                 srcbitmap->name) < 0)
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+                return -1;
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+
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+            if (qemuMonitorTransactionBitmapMerge(actions,
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+                                                  n->nodeformat,
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+                                                  parentbitmap, &arr) < 0)
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                 return -1;
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         }
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-        if (qemuMonitorTransactionBitmapMerge(actions,
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-                                              src->nodeformat,
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-                                              parentbitmap, &arr) < 0)
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+        if (qemuMonitorTransactionBitmapRemove(actions,
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+                                               n->nodeformat,
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+                                               srcbitmap->name) < 0)
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             return -1;
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-    }
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-    if (qemuMonitorTransactionBitmapRemove(actions,
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-                                           src->nodeformat,
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-                                           delbitmap) < 0)
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-        return -1;
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+        n = n->backingStore;
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+    }
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     return 0;
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 }
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@@ -191,11 +245,11 @@ qemuCheckpointDiscardDiskBitmaps(virStorageSourcePtr src,
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 static int
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 qemuCheckpointDiscardBitmaps(virDomainObjPtr vm,
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                              virDomainCheckpointDefPtr chkdef,
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-                             bool chkcurrent,
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                              virDomainMomentObjPtr parent)
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 {
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     qemuDomainObjPrivatePtr priv = vm->privateData;
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     virQEMUDriverPtr driver = priv->driver;
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+    g_autoptr(virHashTable) blockNamedNodeData = NULL;
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     int rc;
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     g_autoptr(virJSONValue) actions = NULL;
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     size_t i;
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@@ -203,6 +257,11 @@ qemuCheckpointDiscardBitmaps(virDomainObjPtr vm,
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     if (!(actions = virJSONValueNewArray()))
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         return -1;
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+    qemuDomainObjEnterMonitor(driver, vm);
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+    blockNamedNodeData = qemuMonitorBlockGetNamedNodeData(priv->mon);
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+    if (qemuDomainObjExitMonitor(priv->driver, vm) < 0 || !blockNamedNodeData)
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+        return -1;
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+
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     for (i = 0; i < chkdef->ndisks; i++) {
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         virDomainCheckpointDiskDef *chkdisk = &chkdef->disks[i];
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         virDomainDiskDefPtr domdisk = virDomainDiskByTarget(vm->def, chkdisk->name);
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@@ -223,8 +282,9 @@ qemuCheckpointDiscardBitmaps(virDomainObjPtr vm,
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                                                                   chkdisk->name)))
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             parentbitmap = parentchkdisk->name;
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-        if (qemuCheckpointDiscardDiskBitmaps(domdisk->src, chkdisk->bitmap,
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-                                             parentbitmap, chkcurrent, actions) < 0)
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+        if (qemuCheckpointDiscardDiskBitmaps(domdisk->src, blockNamedNodeData,
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+                                             chkdisk->bitmap, parentbitmap,
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+                                             actions, domdisk->dst) < 0)
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             return -1;
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     }
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@@ -262,7 +322,7 @@ qemuCheckpointDiscard(virQEMUDriverPtr driver,
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         virDomainCheckpointDefPtr chkdef = virDomainCheckpointObjGetDef(chk);
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         parent = virDomainCheckpointFindByName(vm->checkpoints,
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                                                chk->def->parent_name);
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-        if (qemuCheckpointDiscardBitmaps(vm, chkdef, chkcurrent, parent) < 0)
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+        if (qemuCheckpointDiscardBitmaps(vm, chkdef, parent) < 0)
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             return -1;
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     }
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diff --git a/src/qemu/qemu_checkpoint.h b/src/qemu/qemu_checkpoint.h
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index 85fd453d50..976b1eed0f 100644
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--- a/src/qemu/qemu_checkpoint.h
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+++ b/src/qemu/qemu_checkpoint.h
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@@ -74,7 +74,8 @@ qemuCheckpointRollbackMetadata(virDomainObjPtr vm,
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 int
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 qemuCheckpointDiscardDiskBitmaps(virStorageSourcePtr src,
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+                                 virHashTablePtr blockNamedNodeData,
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                                  const char *delbitmap,
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                                  const char *parentbitmap,
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-                                 bool chkcurrent,
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-                                 virJSONValuePtr actions);
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+                                 virJSONValuePtr actions,
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+                                 const char *diskdst);
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diff --git a/tests/qemublocktest.c b/tests/qemublocktest.c
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index edaf82053d..e56f813424 100644
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--- a/tests/qemublocktest.c
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+++ b/tests/qemublocktest.c
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@@ -704,6 +704,7 @@ struct testQemuCheckpointDeleteMergeData {
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     virStorageSourcePtr chain;
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     const char *deletebitmap;
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     const char *parentbitmap;
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+    const char *nodedatafile;
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 };
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@@ -714,22 +715,30 @@ testQemuCheckpointDeleteMerge(const void *opaque)
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     g_autofree char *actual = NULL;
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     g_autofree char *expectpath = NULL;
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     g_autoptr(virJSONValue) actions = NULL;
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-    bool currentcheckpoint;
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+    g_autoptr(virJSONValue) nodedatajson = NULL;
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+    g_autoptr(virHashTable) nodedata = NULL;
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     expectpath = g_strdup_printf("%s/%s%s-out.json", abs_srcdir,
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                                  checkpointDeletePrefix, data->name);
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+    if (!(nodedatajson = virTestLoadFileJSON(bitmapDetectPrefix, data->nodedatafile,
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+                                             ".json", NULL)))
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+        return -1;
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+
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+    if (!(nodedata = qemuMonitorJSONBlockGetNamedNodeDataJSON(nodedatajson))) {
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+        VIR_TEST_VERBOSE("failed to load nodedata JSON\n");
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+        return -1;
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+    }
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+
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     if (!(actions = virJSONValueNewArray()))
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         return -1;
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-    /* hack to get the 'current' state until the function stops accepting it */
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-    currentcheckpoint = STREQ("current", data->deletebitmap);
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-
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     if (qemuCheckpointDiscardDiskBitmaps(data->chain,
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+                                         nodedata,
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                                          data->deletebitmap,
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                                          data->parentbitmap,
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-                                         currentcheckpoint,
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-                                         actions) < 0) {
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+                                         actions,
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+                                         "testdisk") < 0) {
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         VIR_TEST_VERBOSE("failed to generate checkpoint delete transaction\n");
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         return -1;
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     }
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@@ -988,22 +997,23 @@ mymain(void)
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     TEST_BACKUP_BITMAP_CALCULATE("snapshot-intermediate", bitmapSourceChain, "d", "snapshots");
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     TEST_BACKUP_BITMAP_CALCULATE("snapshot-deep", bitmapSourceChain, "a", "snapshots");
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-#define TEST_CHECKPOINT_DELETE_MERGE(testname, delbmp, parbmp) \
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+#define TEST_CHECKPOINT_DELETE_MERGE(testname, delbmp, parbmp, named) \
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     do { \
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         checkpointdeletedata.name = testname; \
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         checkpointdeletedata.chain = bitmapSourceChain; \
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         checkpointdeletedata.deletebitmap = delbmp; \
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         checkpointdeletedata.parentbitmap = parbmp; \
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+        checkpointdeletedata.nodedatafile = named; \
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         if (virTestRun("checkpoint delete " testname, \
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                        testQemuCheckpointDeleteMerge, &checkpointdeletedata) < 0) \
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         ret = -1; \
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     } while (0)
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-    TEST_CHECKPOINT_DELETE_MERGE("basic-noparent", "a", NULL);
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-    TEST_CHECKPOINT_DELETE_MERGE("basic-intermediate1", "b", "a");
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-    TEST_CHECKPOINT_DELETE_MERGE("basic-intermediate2", "c", "b");
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-    TEST_CHECKPOINT_DELETE_MERGE("basic-intermediate3", "d", "c");
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-    TEST_CHECKPOINT_DELETE_MERGE("basic-current", "current", "d");
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+    TEST_CHECKPOINT_DELETE_MERGE("basic-noparent", "a", NULL, "basic");
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+    TEST_CHECKPOINT_DELETE_MERGE("basic-intermediate1", "b", "a", "basic");
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+    TEST_CHECKPOINT_DELETE_MERGE("basic-intermediate2", "c", "b", "basic");
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+    TEST_CHECKPOINT_DELETE_MERGE("basic-intermediate3", "d", "c", "basic");
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+    TEST_CHECKPOINT_DELETE_MERGE("basic-current", "current", "d", "basic");
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  cleanup:
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     virHashFree(diskxmljsondata.schema);
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-- 
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2.25.0
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