diff options
| -rw-r--r-- | block/nbd-client.c | 8 | ||||
| -rw-r--r-- | include/block/nbd.h | 4 | ||||
| -rw-r--r-- | nbd/client.c | 46 |
3 files changed, 40 insertions, 18 deletions
diff --git a/block/nbd-client.c b/block/nbd-client.c index 5ce4aa9..60f38f0 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -84,15 +84,9 @@ static coroutine_fn void nbd_connection_entry(void *opaque) * * Therefore we keep an additional in_flight reference all the time and * only drop it temporarily here. - * - * FIXME This is not safe because the QIOChannel could wake up the - * coroutine for a second time; it is not prepared for coroutine - * resumption from external code. */ - bdrv_dec_in_flight(s->bs); assert(s->reply.handle == 0); - ret = nbd_receive_reply(s->ioc, &s->reply, &local_err); - bdrv_inc_in_flight(s->bs); + ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, &local_err); if (local_err) { trace_nbd_read_reply_entry_fail(ret, error_get_pretty(local_err)); diff --git a/include/block/nbd.h b/include/block/nbd.h index cad975e..c6ef1ef 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -300,8 +300,8 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, Error **errp); int nbd_send_request(QIOChannel *ioc, NBDRequest *request); -int coroutine_fn nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, - Error **errp); +int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc, + NBDReply *reply, Error **errp); int nbd_client(int fd); int nbd_disconnect(int fd); int nbd_errno_to_system_errno(int err); diff --git a/nbd/client.c b/nbd/client.c index 28d174c..de7da48 100644 --- a/nbd/client.c +++ b/nbd/client.c @@ -1394,30 +1394,58 @@ static int nbd_receive_structured_reply_chunk(QIOChannel *ioc, * negative errno on failure (errp is set) */ static inline int coroutine_fn -nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size, Error **errp) +nbd_read_eof(BlockDriverState *bs, QIOChannel *ioc, void *buffer, size_t size, + Error **errp) { - int ret; + bool partial = false; assert(size); - ret = qio_channel_read_all_eof(ioc, buffer, size, errp); - if (ret < 0) { - ret = -EIO; + while (size > 0) { + struct iovec iov = { .iov_base = buffer, .iov_len = size }; + ssize_t len; + + len = qio_channel_readv(ioc, &iov, 1, errp); + if (len == QIO_CHANNEL_ERR_BLOCK) { + bdrv_dec_in_flight(bs); + qio_channel_yield(ioc, G_IO_IN); + bdrv_inc_in_flight(bs); + continue; + } else if (len < 0) { + return -EIO; + } else if (len == 0) { + if (partial) { + error_setg(errp, + "Unexpected end-of-file before all bytes were read"); + return -EIO; + } else { + return 0; + } + } + + partial = true; + size -= len; + buffer = (uint8_t*) buffer + len; } - return ret; + return 1; } /* nbd_receive_reply + * + * Decreases bs->in_flight while waiting for a new reply. This yield is where + * we wait indefinitely and the coroutine must be able to be safely reentered + * for nbd_client_attach_aio_context(). + * * Returns 1 on success * 0 on eof, when no data was read (errp is not set) * negative errno on failure (errp is set) */ -int coroutine_fn nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, - Error **errp) +int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc, + NBDReply *reply, Error **errp) { int ret; const char *type; - ret = nbd_read_eof(ioc, &reply->magic, sizeof(reply->magic), errp); + ret = nbd_read_eof(bs, ioc, &reply->magic, sizeof(reply->magic), errp); if (ret <= 0) { return ret; } |