[PATCH] qemu: snapshot: Prevent too-nested domain XML when doing inactive snapshot

[Peter Krempa]

Similarly to 510d154a0b41aa70aadabc0918d16dee22882394 we need to prevent
doing too deeply nested backing chains and reject them with a sane error
message.

Add a loop to go through the snapshots prior to attempting actually
creating them to prevent some possible inconsistent scenarios.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_driver.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 2f66d7cd9a..4cebb54913 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -14618,6 +14618,16 @@ qemuDomainSnapshotCreateInactiveExternal(virQEMUDriverPtr driver,
     if (!(created = virBitmapNew(snapdef->ndisks)))
         goto cleanup;

+    for (i = 0; i < snapdef->ndisks && !reuse; i++) {
+        snapdisk = &(snapdef->disks[i]);
+        defdisk = snapdef->parent.dom->disks[snapdisk->idx];
+        if (snapdisk->snapshot != VIR_DOMAIN_SNAPSHOT_LOCATION_EXTERNAL)
+            continue;
+
+        if (qemuDomainStorageSourceValidateDepth(defdisk->src, 1, defdisk->dst) < 0)
+            return -1;
+    }
+
     /* If reuse is true, then qemuDomainSnapshotPrepare already
      * ensured that the new files exist, and it was up to the user to
      * create them correctly.  */
-- 
2.24.1