So that NBD export cannot submit IO during bdrv_drain_all().
Signed-off-by: Fam Zheng <f...@redhat.com>
---
nbd.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/nbd.c b/nbd.c
index 06b501b..b5026af 100644
--- a/nbd.c
+++ b/nbd.c
@@ -160,6 +160,8 @@ struct NBDExport {
uint32_t nbdflags;
QTAILQ_HEAD(, NBDClient) clients;
QTAILQ_ENTRY(NBDExport) next;
+ Notifier blocker_notifier;
+ bool io_blocked;
AioContext *ctx;
};
@@ -1053,6 +1055,22 @@ static void blk_aio_detach(void *opaque)
exp->ctx = NULL;
}
+static void nbd_op_blocker_changed(Notifier *notifier, void *data)
+{
+ BlockOpEvent *event = data;
+ NBDClient *client;
+ NBDExport *exp = container_of(notifier, NBDExport, blocker_notifier);
+
+ if (event->type != BLOCK_OP_TYPE_DEVICE_IO) {
+ return;
+ }
+ exp->io_blocked = event->blocking;
+
+ QTAILQ_FOREACH(client, &exp->clients, next) {
+ nbd_update_can_read(client);
+ }
+}
+
NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
uint32_t nbdflags, void (*close)(NBDExport *),
Error **errp)
@@ -1081,6 +1099,8 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t
dev_offset, off_t size,
* access since the export could be available before migration handover.
*/
blk_invalidate_cache(blk, NULL);
+ exp->blocker_notifier.notify = nbd_op_blocker_changed;
+ blk_op_blocker_add_notifier(blk, &exp->blocker_notifier);
return exp;
fail:
@@ -1132,6 +1152,7 @@ void nbd_export_close(NBDExport *exp)
nbd_export_set_name(exp, NULL);
nbd_export_put(exp);
if (exp->blk) {
+ notifier_remove(&exp->blocker_notifier);
blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
blk_aio_detach, exp);
blk_unref(exp->blk);
@@ -1455,6 +1476,9 @@ static void nbd_update_can_read(NBDClient *client)
bool can_read = client->recv_coroutine ||
client->nb_requests < MAX_NBD_REQUESTS;
+ if (client->exp && client->exp->io_blocked) {
+ can_read = false;
+ }
if (can_read != client->can_read) {
client->can_read = can_read;
nbd_set_handlers(client);
--
2.4.1
