qapi: Convert blockdev_snapshot_sync

Unfortunately, this conversion required an additional change.

In the old QMP command, the 'snapshot-file' argument is specified as
optional. The idea is to take the snapshot internally if 'snapshot-file'
is not passed. However, internal snapshots are not supported yet so
the command returns a MissingParamater error if 'snapshot-file' is not
passed. Which makes the argument actually required and will cause
compatibility breakage if we change that in the future.

To fix this the QAPI converted blockdev_snapshot_sync command makes the
'snapshot-file' argument required. Again, in practice it's actually required,
so this is not incompatible.

If we do implement internal snapshots someday, we'll need a new argument
for it.

Note that this discussion doesn't affect HMP.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

1 files changed, 17 insertions, 32 deletions

diff --git a/blockdev.c b/blockdev.c
index 527040487c..c832782d03 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -601,28 +601,20 @@ void do_commit(Monitor *mon, const QDict *qdict)
     }
 }
 
-int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
+void qmp_blockdev_snapshot_sync(const char *device, const char *snapshot_file,
+                                bool has_format, const char *format,
+                                Error **errp)
 {
-    const char *device = qdict_get_str(qdict, "device");
-    const char *filename = qdict_get_try_str(qdict, "snapshot-file");
-    const char *format = qdict_get_try_str(qdict, "format");
     BlockDriverState *bs;
     BlockDriver *drv, *old_drv, *proto_drv;
     int ret = 0;
     int flags;
     char old_filename[1024];
 
-    if (!filename) {
-        qerror_report(QERR_MISSING_PARAMETER, "snapshot-file");
-        ret = -1;
-        goto out;
-    }
-
     bs = bdrv_find(device);
     if (!bs) {
-        qerror_report(QERR_DEVICE_NOT_FOUND, device);
-        ret = -1;
-        goto out;
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return;
     }
 
     pstrcpy(old_filename, sizeof(old_filename), bs->filename);
@@ -630,35 +622,34 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
     old_drv = bs->drv;
     flags = bs->open_flags;
 
-    if (!format) {
+    if (!has_format) {
         format = "qcow2";
     }
 
     drv = bdrv_find_format(format);
     if (!drv) {
-        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
-        ret = -1;
-        goto out;
+        error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
+        return;
     }
 
-    proto_drv = bdrv_find_protocol(filename);
+    proto_drv = bdrv_find_protocol(snapshot_file);
     if (!proto_drv) {
-        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
-        ret = -1;
-        goto out;
+        error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
+        return;
     }
 
-    ret = bdrv_img_create(filename, format, bs->filename,
+    ret = bdrv_img_create(snapshot_file, format, bs->filename,
                           bs->drv->format_name, NULL, -1, flags);
     if (ret) {
-        goto out;
+        error_set(errp, QERR_UNDEFINED_ERROR);
+        return;
     }
 
     bdrv_drain_all();
     bdrv_flush(bs);
 
     bdrv_close(bs);
-    ret = bdrv_open(bs, filename, flags, drv);
+    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
@@ -667,17 +658,11 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
     if (ret != 0) {
         ret = bdrv_open(bs, old_filename, flags, old_drv);
         if (ret != 0) {
-            qerror_report(QERR_OPEN_FILE_FAILED, old_filename);
+            error_set(errp, QERR_OPEN_FILE_FAILED, old_filename);
         } else {
-            qerror_report(QERR_OPEN_FILE_FAILED, filename);
+            error_set(errp, QERR_OPEN_FILE_FAILED, snapshot_file);
         }
     }
-out:
-    if (ret) {
-        ret = -1;
-    }
-
-    return ret;
 }
 
 static int eject_device(Monitor *mon, BlockDriverState *bs, int force)