Commit a12a712a authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Max Reitz
Browse files

nbd-client: fix handling of hungup connections 



After the switch to reading replies in a coroutine, nothing is
reentering pending receive coroutines if the connection hangs.
Move nbd_recv_coroutines_enter_all to the reply read coroutine,
which is the place where hangups are detected.  nbd_teardown_connection
can simply wait for the reply read coroutine to detect the hangup
and clean up after itself.

This wouldn't be enough though because nbd_receive_reply returns 0
(rather than -EPIPE or similar) when reading from a hung connection.
Fix the return value check in nbd_read_reply_entry.

This fixes qemu-iotests 083.

Reported-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20170314111157.14464-1-pbonzini@redhat.com
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent c9192973

block/nbd-client.c

+6 −6
Original line number Diff line number Diff line
@@ -33,17 +33,15 @@ 
#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ ((uint64_t)(intptr_t)bs))

#define INDEX_TO_HANDLE(bs, index)  ((index)  ^ ((uint64_t)(intptr_t)bs))



static void nbd_recv_coroutines_enter_all(BlockDriverState *bs)

static void nbd_recv_coroutines_enter_all(NBDClientSession *s)

{

    NBDClientSession *s = nbd_get_client_session(bs);

    int i;



    for (i = 0; i < MAX_NBD_REQUESTS; i++) {

        if (s->recv_coroutine[i]) {

            qemu_coroutine_enter(s->recv_coroutine[i]);

            aio_co_wake(s->recv_coroutine[i]);

        }

    }

    BDRV_POLL_WHILE(bs, s->read_reply_co);

}



static void nbd_teardown_connection(BlockDriverState *bs)
@@ -58,7 +56,7 @@ static void nbd_teardown_connection(BlockDriverState *bs) 
    qio_channel_shutdown(client->ioc,

                         QIO_CHANNEL_SHUTDOWN_BOTH,

                         NULL);

    nbd_recv_coroutines_enter_all(bs);

    BDRV_POLL_WHILE(bs, client->read_reply_co);



    nbd_client_detach_aio_context(bs);

    object_unref(OBJECT(client->sioc));
@@ -76,7 +74,7 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque) 
    for (;;) {

        assert(s->reply.handle == 0);

        ret = nbd_receive_reply(s->ioc, &s->reply);

        if (ret < 0) {

        if (ret <= 0) {

            break;

        }
@@ -103,6 +101,8 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque) 
        aio_co_wake(s->recv_coroutine[i]);

        qemu_coroutine_yield();

    }



    nbd_recv_coroutines_enter_all(s);

    s->read_reply_co = NULL;

}

nbd/client.c

+1 −1
Original line number Diff line number Diff line
@@ -812,6 +812,6 @@ ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply) 
        LOG("invalid magic (got 0x%" PRIx32 ")", magic);

        return -EINVAL;

    }

    return 0;

    return sizeof(buf);

}