[Qemu-devel] [PATCH 3/3] HMP: show internal snapshots on a single device

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

  This patch add an option to show snapshots on a single block
device, so some snapshot do not exist on other block device
could be shown.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 monitor.c |    6 +++---
 savevm.c  |   55 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 57 insertions(+), 4 deletions(-)

diff --git a/monitor.c b/monitor.c
index ce0e74d..b019618 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2613,9 +2613,9 @@ 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 fa32171..438eb24 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2358,7 +2358,7 @@ void do_delvm(Monitor *mon, const QDict *qdict)
     }
 }
 
-void do_info_snapshots(Monitor *mon, const QDict *qdict)
+static void do_info_snapshots_vm(Monitor *mon)
 {
     BlockDriverState *bs, *bs1;
     QEMUSnapshotInfo *sn_tab, *sn, s, *sn_info = &s;
@@ -2422,6 +2422,59 @@ void do_info_snapshots(Monitor *mon, const QDict *qdict)
 
 }
 
+static void do_info_snapshots_blk(Monitor *mon, const char *device)
+{
+    BlockDriverState *bs;
+    QEMUSnapshotInfo *sn_tab, *sn;
+    int nb_sns, i;
+    char buf[256];
+
+    /* 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 ;
+    }
+
+    nb_sns = bdrv_snapshot_list(bs, &sn_tab);
+    if (nb_sns < 0) {
+        monitor_printf(mon, "Device %s bdrv_snapshot_list: error %d\n",
+                       device, nb_sns);
+        return;
+    }
+
+    if (nb_sns == 0) {
+        monitor_printf(mon, "There is no snapshot available.\n");
+        return;
+    }
+
+    monitor_printf(mon, "Device %s:\n", device);
+    monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
+    for (i = 0; i < nb_sns; i++) {
+        sn = &sn_tab[i];
+        monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn));
+    }
+    g_free(sn_tab);
+    return;
+}
+
+void do_info_snapshots(Monitor *mon, const QDict *qdict)
+{
+    /* Todo, there should be a layer rebuild qdict before enter this func. */
+    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)
 {
     qemu_ram_set_idstr(memory_region_get_ram_addr(mr) & TARGET_PAGE_MASK,
-- 
1.7.1