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@virtuozzo.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- 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@redhat.com>
+{ + 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; +}