[Qemu-devel] [PATCH V12 07/18] block: change VM snapshot checking logic

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

  Original logic is different with load_vmstate(), this patch change it
to be exactly the same with load_vmstate(), so any VM snapshot shown in
qmp/hmp should succeed in load_vmstate().
  Note that, runtime snapshot info maybe different with what is got
in "qemu-img info" as static snapshot info, and this patch clearly
tips it.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 block/qapi.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/block/qapi.c b/block/qapi.c
index 97c5cd4..49c0eb0 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -46,7 +46,18 @@ static bool snapshot_valid_for_vm(const QEMUSnapshotInfo *sn,
        take snapshot, for example, readonly ones, will be ignored in
        load_vmstate(). */
     while ((bs1 = bdrv_next(bs1))) {
-        if (bs1 != bs && bdrv_can_snapshot(bs1)) {
+
+        if (!bdrv_is_inserted(bs1) || bdrv_is_read_only(bs1)) {
+            continue;
+        }
+
+        if (!bdrv_can_snapshot(bs1)) {
+            /* Device is writable but does not support snapshots, will be
+               rejected by load_vmstate(). */
+            return false;
+        }
+
+        if (bs1 != bs) {
             ret = bdrv_snapshot_find(bs1, sn_info, sn->id_str, NULL);
             if (ret < 0) {
                 return false;
-- 
1.7.1