From 562511afa6cef5948e6339596ba5954cb5ed0565 Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Tue, 28 Apr 2020 15:03:11 +0200
Subject: [PATCH] qemu: backup: Split up code traversing checkpoint list
 looking for bitmaps

The algorithm is getting quite complex. Split out the lookup of range of
backing chain storage sources and bitmaps contained in them which
correspond to one checkpoint.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 src/qemu/qemu_backup.c | 113 ++++++++++++++++++++++-------------------
 1 file changed, 62 insertions(+), 51 deletions(-)

diff --git a/src/qemu/qemu_backup.c b/src/qemu/qemu_backup.c
index b317b841cd..8d75b59db2 100644
--- a/src/qemu/qemu_backup.c
+++ b/src/qemu/qemu_backup.c
@@ -173,72 +173,83 @@ qemuBackupDiskDataCleanup(virDomainObjPtr vm,
 }
 
 
+static int
+qemuBackupGetBitmapMergeRange(virStorageSourcePtr from,
+                              const char *bitmapname,
+                              virJSONValuePtr *actions,
+                              virStorageSourcePtr *to,
+                              const char *diskdst,
+                              virHashTablePtr blockNamedNodeData)
+{
+    g_autoptr(virJSONValue) act = virJSONValueNewArray();
+    virStorageSourcePtr tmpsrc = NULL;
+    virStorageSourcePtr n;
+    bool foundbitmap = false;
+
+    for (n = from; virStorageSourceIsBacking(n); n = n->backingStore) {
+        qemuBlockNamedNodeDataBitmapPtr bitmap = NULL;
+
+        if (!(bitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
+                                                             n,
+                                                             bitmapname)))
+            break;
+
+        foundbitmap = true;
+
+        if (bitmap->inconsistent) {
+            virReportError(VIR_ERR_INVALID_ARG,
+                           _("bitmap '%s' for image '%s%u' is inconsistent"),
+                           bitmap->name, diskdst, n->id);
+            return -1;
+        }
+
+        if (qemuMonitorTransactionBitmapMergeSourceAddBitmap(act,
+                                                             n->nodeformat,
+                                                             bitmapname) < 0)
+            return -1;
+
+        tmpsrc = n;
+    }
+
+    if (!foundbitmap) {
+        virReportError(VIR_ERR_INVALID_ARG,
+                       _("failed to find bitmap '%s' in image '%s%u'"),
+                       bitmapname, diskdst, from->id);
+        return -1;
+    }
+
+    *actions = g_steal_pointer(&act);
+    *to = tmpsrc;
+
+    return 0;
+}
+
+
 virJSONValuePtr
 qemuBackupDiskPrepareOneBitmapsChain(virDomainMomentDefPtr *incremental,
                                      virStorageSourcePtr backingChain,
                                      virHashTablePtr blockNamedNodeData,
                                      const char *diskdst)
 {
-    qemuBlockNamedNodeDataBitmapPtr bitmap;
     g_autoptr(virJSONValue) ret = NULL;
     size_t incridx = 0;
+    virStorageSourcePtr n = backingChain;
 
     ret = virJSONValueNewArray();
 
-    if (!(bitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
-                                                         backingChain,
-                                                         incremental[0]->name))) {
-        virReportError(VIR_ERR_INVALID_ARG,
-                       _("failed to find bitmap '%s' in image '%s%u'"),
-                       incremental[0]->name, diskdst, backingChain->id);
-        return NULL;
-    }
+    for (incridx = 0; incremental[incridx]; incridx++) {
+        g_autoptr(virJSONValue) tmp = virJSONValueNewArray();
+        virStorageSourcePtr tmpsrc = NULL;
 
-    while (bitmap) {
-        if (bitmap->inconsistent) {
-            virReportError(VIR_ERR_INVALID_ARG,
-                           _("bitmap '%s' for image '%s%u' is inconsistent"),
-                           bitmap->name, diskdst, backingChain->id);
-            return NULL;
-        }
-
-        if (qemuMonitorTransactionBitmapMergeSourceAddBitmap(ret,
-                                                             backingChain->nodeformat,
-                                                             bitmap->name) < 0)
+        if (qemuBackupGetBitmapMergeRange(n, incremental[incridx]->name,
+                                          &tmp, &tmpsrc, diskdst,
+                                          blockNamedNodeData) < 0)
             return NULL;
 
-        if (backingChain->backingStore &&
-            (bitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
-                                                            backingChain->backingStore,
-                                                            incremental[incridx]->name))) {
-            backingChain = backingChain->backingStore;
-            continue;
-        }
-
-        if (incremental[incridx + 1]) {
-            if ((bitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
-                                                                backingChain,
-                                                                incremental[incridx + 1]->name))) {
-                incridx++;
-                continue;
-            }
-
-            if (backingChain->backingStore &&
-                (bitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
-                                                                backingChain->backingStore,
-                                                                incremental[incridx + 1]->name))) {
-                incridx++;
-                backingChain = backingChain->backingStore;
-                continue;
-            }
-
-            virReportError(VIR_ERR_INVALID_ARG,
-                           _("failed to find bitmap '%s' in image '%s%u'"),
-                           incremental[incridx]->name, diskdst, backingChain->id);
+        if (virJSONValueArrayConcat(ret, tmp) < 0)
             return NULL;
-        } else {
-            break;
-        }
+
+        n = tmpsrc;
     }
 
     return g_steal_pointer(&ret);