Re: [libvirt] [PATCH 10/19] qemu: snapshot: Propagate active bitmaps through external snapshots

Re-create any active persistent bitmap in the snapshot overlay image so that tracking for a checkpoint is persisted. While this basically duplicates data in the allocation map it's currently the only possible way as qemu can't mirror the allocation map into a dirty bitmap if we'd ever want to do a backup. Signed-off-by: Peter Krempa <pkrempa(a)redhat.com&gt; --- src/qemu/qemu_driver.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index d2769dab1a..8ccd6b7c97 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -15223,6 +15223,42 @@ qemuDomainSnapshotDiskCleanup(qemuDomainSnapshotDiskDataPtr data, } +/** + * qemuDomainSnapshotDiskBitmapsPropagate: + * + * This function propagates any active persistent bitmap present in the original + * image into the new snapshot. We leave the original bitmap active as in cases + * when the overlay is discarded (snapshot revert with abandoning the history) + * everything works as expected.

+ * */

+static int +qemuDomainSnapshotDiskBitmapsPropagate(qemuDomainSnapshotDiskDataPtr dd, + virJSONValuePtr actions, + virHashTablePtr blockNamedNodeData) +{ + qemuBlockNamedNodeDataPtr entry; + size_t i; + + if (!(entry = virHashLookup(blockNamedNodeData, dd->disk->src->nodeformat))) + return 0; + + for (i = 0; i < entry->nbitmaps; i++) { + qemuBlockNamedNodeDataBitmapPtr bitmap = entry->bitmaps[i]; + + /* we don't care about temporary, inconsistent, or disabled bitmaps */ + if (!bitmap->persistent || !bitmap->recording || bitmap->inconsistent) + continue; + + if (qemuMonitorTransactionBitmapAdd(actions, dd->src->nodeformat, + bitmap->name, true, false, + bitmap->granularity) < 0)