[Qemu-devel] [PATCH V2 11/11] hmp: show snapshot on single block device

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

  This patch use block layer API to qmp snapshot info on a block
device, then use the same code dumping vm snapshot info, to print
in monitor.

Note:
  This patch need previous hmp extention patch which enable
info sub command take qdict * as paramter.

v2:
  free SnapshotInfoList after usage.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 monitor.c |    6 +++---
 savevm.c  |   43 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/monitor.c b/monitor.c
index e1bcaa2..3dfdd4d 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2580,9 +2580,9 @@ static mon_cmd_t info_cmds[] = {
     },
     {
         .name       = "snapshots",
-        .args_type  = "",
-        .params     = "",
-        .help       = "show the currently saved VM snapshots",
+        .args_type  = "device:B?",
+        .params     = "[device]",
+        .help       = "show snapshots of whole vm or a single device",
         .mhandler.info = do_info_snapshots,
     },
     {
diff --git a/savevm.c b/savevm.c
index cabdcb6..cd474e9 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2354,9 +2354,50 @@ static void do_info_snapshots_vm(Monitor *mon)
     return;
 }
 
+static void do_info_snapshots_blk(Monitor *mon, const char *device)
+{
+    Error *err = NULL;
+    SnapshotInfoList *list;
+    BlockDriverState *bs;
+
+    /* find the target bs */
+    bs = bdrv_find(device);
+    if (!bs) {
+        monitor_printf(mon, "Device '%s' not found.\n", device);
+        return ;
+    }
+
+    if (!bdrv_can_snapshot(bs)) {
+        monitor_printf(mon, "Device '%s' can't have snapshot.\n", device);
+        return ;
+    }
+
+    list = bdrv_query_snapshot_infolist(bs, NULL, NULL, &err);
+    if (error_is_set(&err)) {
+        hmp_handle_error(mon, &err);
+        return;
+    }
+
+    if (list == NULL) {
+        monitor_printf(mon, "There is no snapshot available.\n");
+        return;
+    }
+
+    monitor_printf(mon, "Device '%s':\n", device);
+    monitor_dump_snapshotinfolist(mon, list);
+    qapi_free_SnapshotInfoList(list);
+    return;
+}
+
 void do_info_snapshots(Monitor *mon, const QDict *qdict)
 {
-    do_info_snapshots_vm(mon);
+    const char *device = qdict_get_try_str(qdict, "device");
+    if (!device) {
+        do_info_snapshots_vm(mon);
+    } else {
+        do_info_snapshots_blk(mon, device);
+    }
+    return;
 }
 
 void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev)
-- 
1.7.1