qmp: convert blockdev-snapshot-sync to a wrapper around transactions

Simplify the blockdev-snapshot-sync code and gain failsafe operation
by turning it into a wrapper around the new transaction command.  A new
option is also added matching "mode".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 23 insertions, 62 deletions

diff --git a/blockdev.c b/blockdev.c
index 0a6edc3e1..1a500b830 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -649,72 +649,33 @@ void do_commit(Monitor *mon, const QDict *qdict)
     }
 }
 
+static void blockdev_do_action(int kind, void *data, Error **errp)
+{
+    BlockdevAction action;
+    BlockdevActionList list;
+
+    action.kind = kind;
+    action.data = data;
+    list.value = &action;
+    list.next = NULL;
+    qmp_transaction(&list, errp);
+}
+
 void qmp_blockdev_snapshot_sync(const char *device, const char *snapshot_file,
                                 bool has_format, const char *format,
+                                bool has_mode, enum NewImageMode mode,
                                 Error **errp)
 {
-    BlockDriverState *bs;
-    BlockDriver *drv, *old_drv, *proto_drv;
-    int ret = 0;
-    int flags;
-    char old_filename[1024];
-
-    bs = bdrv_find(device);
-    if (!bs) {
-        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
-        return;
-    }
-    if (bdrv_in_use(bs)) {
-        error_set(errp, QERR_DEVICE_IN_USE, device);
-        return;
-    }
-
-    pstrcpy(old_filename, sizeof(old_filename), bs->filename);
-
-    old_drv = bs->drv;
-    flags = bs->open_flags;
-
-    if (!has_format) {
-        format = "qcow2";
-    }
-
-    drv = bdrv_find_format(format);
-    if (!drv) {
-        error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
-        return;
-    }
-
-    proto_drv = bdrv_find_protocol(snapshot_file);
-    if (!proto_drv) {
-        error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
-        return;
-    }
-
-    ret = bdrv_img_create(snapshot_file, format, bs->filename,
-                          bs->drv->format_name, NULL, -1, flags);
-    if (ret) {
-        error_set(errp, QERR_UNDEFINED_ERROR);
-        return;
-    }
-
-    bdrv_drain_all();
-    bdrv_flush(bs);
-
-    bdrv_close(bs);
-    ret = bdrv_open(bs, snapshot_file, flags, drv);
-    /*
-     * If reopening the image file we just created fails, fall back
-     * and try to re-open the original image. If that fails too, we
-     * are in serious trouble.
-     */
-    if (ret != 0) {
-        ret = bdrv_open(bs, old_filename, flags, old_drv);
-        if (ret != 0) {
-            error_set(errp, QERR_OPEN_FILE_FAILED, old_filename);
-        } else {
-            error_set(errp, QERR_OPEN_FILE_FAILED, snapshot_file);
-        }
-    }
+    BlockdevSnapshot snapshot = {
+        .device = (char *) device,
+        .snapshot_file = (char *) snapshot_file,
+        .has_format = has_format,
+        .format = (char *) format,
+        .has_mode = has_mode,
+        .mode = mode,
+    };
+    blockdev_do_action(BLOCKDEV_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC, &snapshot,
+                       errp);
 }