From 4fcacae366ef35c336a6b9b0ff35cdf0a3c80760 Mon Sep 17 00:00:00 2001
Message-Id: <4fcacae366ef35c336a6b9b0ff35cdf0a3c80760@dist-git>
From: Peter Krempa <pkrempa@redhat.com>
Date: Tue, 23 Jun 2020 12:23:50 +0200
Subject: [PATCH] qemuBlockBitmapChainIsValid: Adjust to new semantics of
 bitmaps
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Reject duplicates and other problematic bitmaps according to the new
semantics of bitmap use in libvirt.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit 3857b073cb3a44c6a54e040f395ed58531f16634)
https://bugzilla.redhat.com/show_bug.cgi?id=1804593
Message-Id: <a35c63c398ab7fa25758567ec73228c97ba1fe6f.1592906423.git.pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
---
 src/qemu/qemu_block.c | 38 +++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
index a44774c237..38c8269721 100644
--- a/src/qemu/qemu_block.c
+++ b/src/qemu/qemu_block.c
@@ -2835,41 +2835,49 @@ qemuBlockGetNamedNodeData(virDomainObjPtr vm,
 /**
  * qemuBlockBitmapChainIsValid:
  *
- * Validates that the backing chain of @src contains proper consistent bitmap
- * data for a chain of bitmaps named @bitmapname.
+ * Validates that the backing chain of @src contains bitmaps which libvirt will
+ * consider as properly corresponding to a checkpoint named @bitmapname.
  *
- * A valid chain:
- * 1) bitmaps of same name are in a consecutive subset of images without gap
- * 2) don't have any inconsistent bitmaps
+ * The bitmaps need to:
+ * 1) start from the top image @src
+ * 2) must be present in consecutive layers
+ * 3) all must be active, persistent and not inconsistent
  */
 bool
 qemuBlockBitmapChainIsValid(virStorageSourcePtr src,
                             const char *bitmapname,
                             virHashTablePtr blockNamedNodeData)
 {
-    qemuBlockNamedNodeDataBitmapPtr bitmap;
     virStorageSourcePtr n;
-    bool chain_started = false;
+    bool found = false;
     bool chain_ended = false;
 
-    for (n = src; n; n = n->backingStore) {
-        if (!(bitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData, n, bitmapname))) {
-            if (chain_started)
-                chain_ended = true;
+    for (n = src; virStorageSourceIsBacking(n); n = n->backingStore) {
+        qemuBlockNamedNodeDataBitmapPtr bitmap;
+
+        if (!(bitmap = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData,
+                                                             n, bitmapname))) {
+            /* rule 1, must start from top */
+            if (!found)
+                return false;
+
+            chain_ended = true;
 
             continue;
         }
 
+        /* rule 2, no-gaps */
         if (chain_ended)
             return false;
 
-        chain_started = true;
-
-        if (bitmap->inconsistent)
+        /* rule 3 */
+        if (bitmap->inconsistent || !bitmap->persistent || !bitmap->recording)
             return false;
+
+        found = true;
     }
 
-    return chain_started;
+    return found;
 }
 
 
-- 
2.27.0