On 14.10.2020 13:44, Max Reitz wrote:
On 12.10.20 19:43, Andrey Shinkevich wrote:
Provide API for the COR-filter insertion/removal.
Also, drop the filter child permissions for an inactive state when the
filter node is being removed.
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@xxxxxxxxxxxxx>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@xxxxxxxxxxxxx>
---
block/copy-on-read.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++
block/copy-on-read.h | 35 +++++++++++++++++++++
2 files changed, 123 insertions(+)
create mode 100644 block/copy-on-read.h
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index cb03e0f..bcccf0f 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
[...]
@@ -159,4 +188,63 @@ static void bdrv_copy_on_read_init(void)
bdrv_register(&bdrv_copy_on_read);
}
+
+BlockDriverState *bdrv_cor_filter_append(BlockDriverState *bs,
+ QDict *node_options,
+ int flags, Error **errp)
I had hoped you could make this a generic block layer function. :(
(Because it really is rather generic)
*shrug*
Actually, I did (and still can do) that for the 'append node' function
only but not for the 'drop node' one so far...
diff --git a/block.c b/block.c
index 11ab55f..f41e876 100644
--- a/block.c
+++ b/block.c
@@ -4669,6 +4669,55 @@ static void bdrv_delete(BlockDriverState *bs)
g_free(bs);
}
+BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict
*node_options,
+ int flags, Error **errp)
+{
+ BlockDriverState *new_node_bs;
+ Error *local_err = NULL;
+
+ new_node_bs = bdrv_open(NULL, NULL, node_options, flags, errp);
+ if (new_node_bs == NULL) {
+ error_prepend(errp, "Could not create node: ");
+ return NULL;
+ }
+
+ bdrv_drained_begin(bs);
+ bdrv_replace_node(bs, new_node_bs, &local_err);
+ bdrv_drained_end(bs);
+
+ if (local_err) {
+ bdrv_unref(new_node_bs);
+ error_propagate(errp, local_err);
+ return NULL;
+ }
+
+ return new_node_bs;
+}
+
+void bdrv_remove_node(BlockDriverState *bs)
+{
+ BdrvChild *child;
+ BlockDriverState *inferior_bs;
+
+ child = bdrv_filter_or_cow_child(bs);
+ if (!child) {
+ return;
+ }
+ inferior_bs = child->bs;
+
+ /* Retain the BDS until we complete the graph change. */
+ bdrv_ref(inferior_bs);
+ /* Hold a guest back from writing while permissions are being reset. */
+ bdrv_drained_begin(inferior_bs);
+ /* Refresh permissions before the graph change. */
+ bdrv_child_refresh_perms(bs, child, &error_abort);
+ bdrv_replace_node(bs, inferior_bs, &error_abort);
+
+ bdrv_drained_end(inferior_bs);
+ bdrv_unref(inferior_bs);
+ bdrv_unref(bs);
+}
So, it is an intermediate solution in this patch of the series. I am
going to make both functions generic once Vladimir overhauls the QEMU
permission update system. Otherwise, the COR-filter node cannot be
removed from the backing chain gracefully.
Thank you for your r-b. If the next version comes, I can move the
'append node' function only to the generic layer.
Andrey
Reviewed-by: Max Reitz <mreitz@xxxxxxxxxx>
+{
+ BlockDriverState *cor_filter_bs;
+ Error *local_err = NULL;
+
+ cor_filter_bs = bdrv_open(NULL, NULL, node_options, flags, errp);
+ if (cor_filter_bs == NULL) {
+ error_prepend(errp, "Could not create COR-filter node: ");
+ return NULL;
+ }
+
+ if (!qdict_get_try_str(node_options, "node-name")) {
+ cor_filter_bs->implicit = true;
+ }
+
+ bdrv_drained_begin(bs);
+ bdrv_replace_node(bs, cor_filter_bs, &local_err);
+ bdrv_drained_end(bs);
+
+ if (local_err) {
+ bdrv_unref(cor_filter_bs);
+ error_propagate(errp, local_err);
+ return NULL;
+ }
+
+ return cor_filter_bs;
+}
