diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 7e4287bc19e5..3d1fc37a83b1 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -47,6 +47,8 @@ static DEFINE_MUTEX(nbd_index_mutex); struct nbd_sock { struct socket *sock; struct mutex tx_lock; + struct request *pending; + int sent; }; #define NBD_TIMEDOUT 0 @@ -202,7 +204,7 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req, * Send or receive packet. */ static int sock_xmit(struct nbd_device *nbd, int index, int send, - struct iov_iter *iter, int msg_flags) + struct iov_iter *iter, int msg_flags, int *sent) { struct socket *sock = nbd->socks[index]->sock; int result; @@ -237,6 +239,8 @@ static int sock_xmit(struct nbd_device *nbd, int index, int send, result = -EPIPE; /* short read */ break; } + if (sent) + *sent += result; } while (msg_data_left(&msg)); tsk_restore_flags(current, pflags, PF_MEMALLOC); @@ -248,6 +252,7 @@ static int sock_xmit(struct nbd_device *nbd, int index, int send, static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) { struct request *req = blk_mq_rq_from_pdu(cmd); + struct nbd_sock *nsock = nbd->socks[index]; int result; struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)}; struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)}; @@ -256,6 +261,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) struct bio *bio; u32 type; u32 tag = blk_mq_unique_tag(req); + int sent = nsock->sent, skip = 0; iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request)); @@ -283,6 +289,17 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) return -EIO; } + /* We did a partial send previously, and we at least sent the whole + * request struct, so just go and send the rest of the pages in the + * request. + */ + if (sent) { + if (sent >= sizeof(request)) { + skip = sent - sizeof(request); + goto send_pages; + } + iov_iter_advance(&from, sent); + } request.type = htonl(type); if (type != NBD_CMD_FLUSH) { request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); @@ -294,15 +311,27 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) cmd, nbdcmd_to_ascii(type), (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); result = sock_xmit(nbd, index, 1, &from, - (type == NBD_CMD_WRITE) ? MSG_MORE : 0); + (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent); if (result <= 0) { + if (result == -ERESTARTSYS) { + /* If we havne't sent anything we can just return BUSY, + * however if we have sent something we need to make + * sure we only allow this req to be sent until we are + * completely done. + */ + if (sent) { + nsock->pending = req; + nsock->sent = sent; + } + return BLK_MQ_RQ_QUEUE_BUSY; + } dev_err_ratelimited(disk_to_dev(nbd->disk), "Send control failed (result %d)\n", result); return -EIO; } - +send_pages: if (type != NBD_CMD_WRITE) - return 0; + goto out; bio = req->bio; while (bio) { @@ -318,8 +347,25 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) cmd, bvec.bv_len); iov_iter_bvec(&from, ITER_BVEC | WRITE, &bvec, 1, bvec.bv_len); - result = sock_xmit(nbd, index, 1, &from, flags); + if (skip) { + if (skip >= iov_iter_count(&from)) { + skip -= iov_iter_count(&from); + continue; + } + iov_iter_advance(&from, skip); + skip = 0; + } + result = sock_xmit(nbd, index, 1, &from, flags, &sent); if (result <= 0) { + if (result == -ERESTARTSYS) { + /* We've already sent the header, we + * have no choice but to set pending and + * return BUSY. + */ + nsock->pending = req; + nsock->sent = sent; + return BLK_MQ_RQ_QUEUE_BUSY; + } dev_err(disk_to_dev(nbd->disk), "Send data failed (result %d)\n", result); @@ -336,6 +382,9 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) } bio = next; } +out: + nsock->pending = NULL; + nsock->sent = 0; return 0; } @@ -353,7 +402,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) reply.magic = 0; iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply)); - result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL); + result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL); if (result <= 0) { if (!test_bit(NBD_DISCONNECTED, &nbd->runtime_flags) && !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags)) @@ -395,7 +444,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) rq_for_each_segment(bvec, req, iter) { iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, bvec.bv_len); - result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL); + result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", result); @@ -482,22 +531,23 @@ static void nbd_clear_que(struct nbd_device *nbd) } -static void nbd_handle_cmd(struct nbd_cmd *cmd, int index) +static int nbd_handle_cmd(struct nbd_cmd *cmd, int index) { struct request *req = blk_mq_rq_from_pdu(cmd); struct nbd_device *nbd = cmd->nbd; struct nbd_sock *nsock; + int ret; if (index >= nbd->num_connections) { dev_err_ratelimited(disk_to_dev(nbd->disk), "Attempted send on invalid socket\n"); - goto error_out; + return -EINVAL; } if (test_bit(NBD_DISCONNECTED, &nbd->runtime_flags)) { dev_err_ratelimited(disk_to_dev(nbd->disk), "Attempted send on closed socket\n"); - goto error_out; + return -EINVAL; } req->errors = 0; @@ -508,29 +558,30 @@ static void nbd_handle_cmd(struct nbd_cmd *cmd, int index) mutex_unlock(&nsock->tx_lock); dev_err_ratelimited(disk_to_dev(nbd->disk), "Attempted send on closed socket\n"); - goto error_out; + return -EINVAL; } - if (nbd_send_cmd(nbd, cmd, index) != 0) { - dev_err_ratelimited(disk_to_dev(nbd->disk), - "Request send failed\n"); - req->errors++; - nbd_end_request(cmd); + /* Handle the case that we have a pending request that was partially + * transmitted that _has_ to be serviced first. We need to call requeue + * here so that it gets put _after_ the request that is already on the + * dispatch list. + */ + if (unlikely(nsock->pending && nsock->pending != req)) { + blk_mq_requeue_request(req, true); + ret = 0; + goto out; } - + ret = nbd_send_cmd(nbd, cmd, index); +out: mutex_unlock(&nsock->tx_lock); - - return; - -error_out: - req->errors++; - nbd_end_request(cmd); + return ret; } static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); + int ret; /* * Since we look at the bio's to send the request over the network we @@ -543,10 +594,20 @@ static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx, */ init_completion(&cmd->send_complete); blk_mq_start_request(bd->rq); - nbd_handle_cmd(cmd, hctx->queue_num); + + /* We can be called directly from the user space process, which means we + * could possibly have signals pending so our sendmsg will fail. In + * this case we need to return that we are busy, otherwise error out as + * appropriate. + */ + ret = nbd_handle_cmd(cmd, hctx->queue_num); + if (ret < 0) + ret = BLK_MQ_RQ_QUEUE_ERROR; + if (!ret) + ret = BLK_MQ_RQ_QUEUE_OK; complete(&cmd->send_complete); - return BLK_MQ_RQ_QUEUE_OK; + return ret; } static int nbd_add_socket(struct nbd_device *nbd, struct block_device *bdev, @@ -581,6 +642,8 @@ static int nbd_add_socket(struct nbd_device *nbd, struct block_device *bdev, mutex_init(&nsock->tx_lock); nsock->sock = sock; + nsock->pending = NULL; + nsock->sent = 0; socks[nbd->num_connections++] = nsock; if (max_part) @@ -634,7 +697,7 @@ static void send_disconnects(struct nbd_device *nbd) for (i = 0; i < nbd->num_connections; i++) { iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request)); - ret = sock_xmit(nbd, i, 1, &from, 0); + ret = sock_xmit(nbd, i, 1, &from, 0, NULL); if (ret <= 0) dev_err(disk_to_dev(nbd->disk), "Send disconnect failed %d\n", ret);