From 2b9091f089279a7bac523095a2ccd146fa20800b Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Tue, 3 Mar 2020 13:59:48 +0100
Subject: [PATCH] qemuDomainBlockCommit: Handle bitmaps on start of commit

On start of the commit job, we need to disable any active bitmap in the
base. Use qemuBlockBitmapsHandleCommitStart to calculate which and call
the appropriate QMP APIs. We use blockdev-reopen to make the 'base'
writable to disable the bitmaps.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 src/qemu/qemu_driver.c | 43 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 2799094fe6..3d5633f1e9 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -18399,6 +18399,8 @@ qemuDomainBlockCommit(virDomainPtr dom,
     const char *nodebase = NULL;
     bool persistjob = false;
     bool blockdev = false;
+    g_autoptr(virJSONValue) bitmapDisableActions = NULL;
+    VIR_AUTOSTRINGLIST bitmapDisableList = NULL;
 
     virCheckFlags(VIR_DOMAIN_BLOCK_COMMIT_SHALLOW |
                   VIR_DOMAIN_BLOCK_COMMIT_ACTIVE |
@@ -18555,8 +18557,29 @@ qemuDomainBlockCommit(virDomainPtr dom,
             goto endjob;
     }
 
+    if (blockdev &&
+        virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV_REOPEN)) {
+        g_autoptr(virHashTable) blockNamedNodeData = NULL;
+        if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, QEMU_ASYNC_JOB_NONE)))
+            goto endjob;
+
+        if (qemuBlockBitmapsHandleCommitStart(topSource, baseSource,
+                                              blockNamedNodeData,
+                                              &bitmapDisableActions,
+                                              &bitmapDisableList) < 0)
+            goto endjob;
+
+        /* if we don't have terminator on 'base' we can't reopen it */
+        if (bitmapDisableActions && !baseSource->backingStore) {
+            virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+                           _("can't handle bitmaps on unterminated backing image '%s'"),
+                           base);
+            goto endjob;
+        }
+    }
+
     if (!(job = qemuBlockJobDiskNewCommit(vm, disk, top_parent, topSource,
-                                          baseSource, NULL,
+                                          baseSource, &bitmapDisableList,
                                           flags & VIR_DOMAIN_BLOCK_COMMIT_DELETE,
                                           flags)))
         goto endjob;
@@ -18578,6 +18601,24 @@ qemuDomainBlockCommit(virDomainPtr dom,
         if (!backingPath && top_parent &&
             !(backingPath = qemuBlockGetBackingStoreString(baseSource)))
             goto endjob;
+
+        if (bitmapDisableActions) {
+            int rc;
+
+            if (qemuBlockReopenReadWrite(vm, baseSource, QEMU_ASYNC_JOB_NONE) < 0)
+                goto endjob;
+
+            qemuDomainObjEnterMonitor(driver, vm);
+            rc = qemuMonitorTransaction(priv->mon, &bitmapDisableActions);
+            if (qemuDomainObjExitMonitor(driver, vm) < 0)
+                goto endjob;
+
+            if (qemuBlockReopenReadOnly(vm, baseSource, QEMU_ASYNC_JOB_NONE) < 0)
+                goto endjob;
+
+            if (rc < 0)
+                goto endjob;
+        }
     } else {
         device = job->name;
     }
-- 
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