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nbd: Increase bs->in_flight during AioContext switch

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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 <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2019-02-18 15:33:08 +01:00
parent d3bd5b9089
commit 28e0b2d2e1
1 changed files with 18 additions and 2 deletions
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20
block/nbd-client.c
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@ -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)