commit 077e8e2018bce66aa1d1a87fa42beb24992c490f
author Alberto Garcia <berto@igalia.com> Tue Mar 12 18:48:44 2019 +0200
committer Kevin Wolf <kwolf@redhat.com> Tue Mar 12 20:30:14 2019 +0100
tree 6d10ab50b5b37237fe4debb701deb83d974aa537
parent 6585493369819a48d34a86d57ec6b97cb5cd9bc0

block: Add 'keep_old_opts' parameter to bdrv_reopen_queue()

The bdrv_reopen_queue() function is used to create a queue with
the BDSs that are going to be reopened and their new options. Once
the queue is ready bdrv_reopen_multiple() is called to perform the
operation.

The original options from each one of the BDSs are kept, with the new
options passed to bdrv_reopen_queue() applied on top of them.

For "x-blockdev-reopen" we want a function that behaves much like
"blockdev-add". We want to ignore the previous set of options so that
only the ones actually specified by the user are applied, with the
rest having their default values.

One of the things that we need is a way to tell bdrv_reopen_queue()
whether we want to keep the old set of options or not, and that's what
this patch does. All current callers are setting this new parameter to
true and x-blockdev-reopen will set it to false.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

diff --git a/block.c b/block.c
index a2bffce..3cd281d 100644
--- a/block.c
+++ b/block.c
@@ -3010,7 +3010,8 @@
                                                  QDict *options,
                                                  const BdrvChildRole *role,
                                                  QDict *parent_options,
-                                                 int parent_flags)
+                                                 int parent_flags,
+                                                 bool keep_old_opts)
 {
     assert(bs != NULL);
 
@@ -3050,13 +3051,13 @@
      */
 
     /* Old explicitly set values (don't overwrite by inherited value) */
-    if (bs_entry) {
-        old_options = qdict_clone_shallow(bs_entry->state.explicit_options);
-    } else {
-        old_options = qdict_clone_shallow(bs->explicit_options);
+    if (bs_entry || keep_old_opts) {
+        old_options = qdict_clone_shallow(bs_entry ?
+                                          bs_entry->state.explicit_options :
+                                          bs->explicit_options);
+        bdrv_join_options(bs, options, old_options);
+        qobject_unref(old_options);
     }
-    bdrv_join_options(bs, options, old_options);
-    qobject_unref(old_options);
 
     explicit_options = qdict_clone_shallow(options);
 
@@ -3068,10 +3069,12 @@
         flags = bdrv_get_flags(bs);
     }
 
-    /* Old values are used for options that aren't set yet */
-    old_options = qdict_clone_shallow(bs->options);
-    bdrv_join_options(bs, options, old_options);
-    qobject_unref(old_options);
+    if (keep_old_opts) {
+        /* Old values are used for options that aren't set yet */
+        old_options = qdict_clone_shallow(bs->options);
+        bdrv_join_options(bs, options, old_options);
+        qobject_unref(old_options);
+    }
 
     /* We have the final set of options so let's update the flags */
     options_copy = qdict_clone_shallow(options);
@@ -3121,7 +3124,7 @@
         g_free(child_key_dot);
 
         bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
-                                child->role, options, flags);
+                                child->role, options, flags, keep_old_opts);
     }
 
     return bs_queue;
@@ -3129,9 +3132,10 @@
 
 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                     BlockDriverState *bs,
-                                    QDict *options)
+                                    QDict *options, bool keep_old_opts)
 {
-    return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, NULL, 0);
+    return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, NULL, 0,
+                                   keep_old_opts);
 }
 
 /*
@@ -3224,7 +3228,7 @@
     qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only);
 
     bdrv_subtree_drained_begin(bs);
-    queue = bdrv_reopen_queue(NULL, bs, opts);
+    queue = bdrv_reopen_queue(NULL, bs, opts, true);
     ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, errp);
     bdrv_subtree_drained_end(bs);