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[Qemu-devel] [PATCH v2 08/13] nbd: Increase bs->in_flight during AioCont
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH v2 08/13] nbd: Increase bs->in_flight during AioContext switch |
Date: |
Wed, 20 Feb 2019 18:48:38 +0100 |
bdrv_drain() must not leave connection_co scheduled, so bs->in_flight
needs to be increased while the coroutine is waiting to be scheduled
in the new AioContext after nbd_client_attach_aio_context().
Signed-off-by: Kevin Wolf <address@hidden>
---
block/nbd-client.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/block/nbd-client.c b/block/nbd-client.c
index 60f38f0320..bfbaf7ebe9 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -977,14 +977,30 @@ void nbd_client_detach_aio_context(BlockDriverState *bs)
qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc));
}
+static void nbd_client_attach_aio_context_bh(void *opaque)
+{
+ BlockDriverState *bs = opaque;
+ NBDClientSession *client = nbd_get_client_session(bs);
+
+ /* The node is still drained, so we know the coroutine has yielded in
+ * nbd_read_eof(), the only place where bs->in_flight can reach 0, or it is
+ * entered for the first time. Both places are safe for entering the
+ * coroutine.*/
+ qemu_aio_coroutine_enter(bs->aio_context, client->connection_co);
+ bdrv_dec_in_flight(bs);
+}
+
void nbd_client_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
NBDClientSession *client = nbd_get_client_session(bs);
qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc), new_context);
- /* FIXME Really need a bdrv_inc_in_flight() here */
- aio_co_schedule(new_context, client->connection_co);
+ bdrv_inc_in_flight(bs);
+
+ /* Need to wait here for the BH to run because the BH must run while the
+ * node is still drained. */
+ aio_wait_bh_oneshot(new_context, nbd_client_attach_aio_context_bh, bs);
}
void nbd_client_close(BlockDriverState *bs)
--
2.20.1
- [Qemu-devel] [PATCH v2 03/13] nbd: Restrict connection_co reentrance, (continued)
[Qemu-devel] [PATCH v2 04/13] io: Make qio_channel_yield() interruptible, Kevin Wolf, 2019/02/20
[Qemu-devel] [PATCH v2 06/13] nbd: Move nbd_read_eof() to nbd/client.c, Kevin Wolf, 2019/02/20
[Qemu-devel] [PATCH v2 09/13] block: Don't poll in bdrv_set_aio_context(), Kevin Wolf, 2019/02/20
[Qemu-devel] [PATCH v2 07/13] nbd: Use low-level QIOChannel API in nbd_read_eof(), Kevin Wolf, 2019/02/20
[Qemu-devel] [PATCH v2 08/13] nbd: Increase bs->in_flight during AioContext switch,
Kevin Wolf <=
[Qemu-devel] [PATCH v2 10/13] block: Fix AioContext switch for drained node, Kevin Wolf, 2019/02/20
[Qemu-devel] [PATCH v2 11/13] test-bdrv-drain: AioContext switch in drained section, Kevin Wolf, 2019/02/20
[Qemu-devel] [PATCH v2 12/13] block: Use normal drain for bdrv_set_aio_context(), Kevin Wolf, 2019/02/20
[Qemu-devel] [PATCH v2 13/13] aio-posix: Assert that aio_poll() is always called in home thread, Kevin Wolf, 2019/02/20
Re: [Qemu-devel] [PATCH v2 00/13] block: bdrv_set_aio_context() related fixes, Kevin Wolf, 2019/02/25