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[Qemu-devel] [PATCH v2 13/13] nbd-server: Clear "can_read" when backend
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH v2 13/13] nbd-server: Clear "can_read" when backend is locked |
Date: |
Tue, 2 Jun 2015 11:22:02 +0800 |
So that NBD export will not process more requests.
Signed-off-by: Fam Zheng <address@hidden>
---
nbd.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/nbd.c b/nbd.c
index 06b501b..854d6a5 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 lock_notify;
+ bool io_blocked;
AioContext *ctx;
};
@@ -1053,6 +1055,19 @@ static void blk_aio_detach(void *opaque)
exp->ctx = NULL;
}
+static void nbd_pause_handler(Notifier *notifier, void *data)
+{
+ BdrvLockEvent *event = data;
+ NBDClient *client;
+ NBDExport *exp = container_of(notifier, NBDExport, lock_notify);
+
+ exp->io_blocked = event->locking;
+
+ 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 +1096,8 @@ 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->lock_notify.notify = nbd_pause_handler;
+ blk_add_lock_unlock_notifier(blk, &exp->lock_notify);
return exp;
fail:
@@ -1132,6 +1149,7 @@ void nbd_export_close(NBDExport *exp)
nbd_export_set_name(exp, NULL);
nbd_export_put(exp);
if (exp->blk) {
+ notifier_remove(&exp->lock_notify);
blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
blk_aio_detach, exp);
blk_unref(exp->blk);
@@ -1455,6 +1473,9 @@ 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
- [Qemu-devel] [PATCH v2 03/13] blockdev: Lock BDS during internal snapshot transaction, (continued)
- [Qemu-devel] [PATCH v2 03/13] blockdev: Lock BDS during internal snapshot transaction, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 04/13] blockdev: Lock BDS during external snapshot transaction, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 05/13] blockdev: Lock BDS during drive-backup transaction, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 06/13] blockdev: Lock BDS during blockdev-backup transaction, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 07/13] mirror: Protect source between bdrv_drain and bdrv_swap, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 08/13] block: Add bdrv_add_lock_unlock_notifier, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 09/13] block-backend: Add blk_add_lock_unlock_notifier, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 10/13] virtio-blk: Move complete_request to 'ops' structure, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 11/13] virtio-blk: Don't handle output when backend is locked, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 12/13] virtio-scsi-dataplane: Add backend lock listener, Fam Zheng, 2015/06/01
- [Qemu-devel] [PATCH v2 13/13] nbd-server: Clear "can_read" when backend is locked,
Fam Zheng <=