commit 8b1869daad17f313bf9a68fd3275448df0ecb7fb
author Max Reitz <mreitz@redhat.com> Wed May 13 13:05:35 2020 +0200
committer Kevin Wolf <kwolf@redhat.com> Mon May 18 19:05:25 2020 +0200
tree d6686fc9a54daf85e6a893fa093ae8d7864bb570
parent ff3541c4e27030fe681d0613ef69bdffb0e29f3a

block: Make format drivers use child_of_bds

Commonly, they need to pass the BDRV_CHILD_IMAGE set as the
BdrvChildRole; but there are exceptions for drivers with external data
files (qcow2 and vmdk).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200513110544.176672-26-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/qcow2.c

diff --git a/block/qcow2.c b/block/qcow2.c
index 86335d9..8d7230d 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1590,8 +1590,9 @@
     }
 
     /* Open external data file */
-    s->data_file = bdrv_open_child(NULL, options, "data-file", bs, &child_file,
-                                   0, true, &local_err);
+    s->data_file = bdrv_open_child(NULL, options, "data-file", bs,
+                                   &child_of_bds, BDRV_CHILD_DATA,
+                                   true, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
@@ -1601,8 +1602,8 @@
     if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
         if (!s->data_file && s->image_data_file) {
             s->data_file = bdrv_open_child(s->image_data_file, options,
-                                           "data-file", bs, &child_file, 0,
-                                           false, errp);
+                                           "data-file", bs, &child_of_bds,
+                                           BDRV_CHILD_DATA, false, errp);
             if (!s->data_file) {
                 ret = -EINVAL;
                 goto fail;
@@ -1613,6 +1614,12 @@
             ret = -EINVAL;
             goto fail;
         }
+
+        /* No data here */
+        bs->file->role &= ~BDRV_CHILD_DATA;
+
+        /* Must succeed because we have given up permissions if anything */
+        bdrv_child_refresh_perms(bs, bs->file, &error_abort);
     } else {
         if (s->data_file) {
             error_setg(errp, "'data-file' can only be set for images with an "
@@ -1863,8 +1870,8 @@
         .ret = -EINPROGRESS
     };
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }