@@ -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);