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* [Patch (resend) 1/5] cifs: smbd: Don't destroy transport on RDMA disconnect
@ 2019-04-05 21:36 Long Li
  2019-04-05 21:36 ` [Patch (resend) 2/5] cifs: smbd: Return EINTR when interrupted Long Li
                   ` (3 more replies)
  0 siblings, 4 replies; 7+ messages in thread
From: Long Li @ 2019-04-05 21:36 UTC (permalink / raw)
  To: Steve French, linux-cifs, samba-technical, linux-kernel; +Cc: Long Li

From: Long Li <longli@microsoft.com>

Now upper layer is handling the transport shutdown and reconnect, remove
the code that handling transport shutdown on RDMA disconnect.

Signed-off-by: Long Li <longli@microsoft.com>
---
 fs/cifs/cifs_debug.c |   8 ++--
 fs/cifs/smbdirect.c  | 120 +++------------------------------------------------
 fs/cifs/smbdirect.h  |   9 ----
 3 files changed, 10 insertions(+), 127 deletions(-)

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 19ed9ab..5ff0b3d 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -312,12 +312,10 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 			atomic_read(&server->smbd_conn->send_credits),
 			atomic_read(&server->smbd_conn->receive_credits),
 			server->smbd_conn->receive_credit_target);
-		seq_printf(m, "\nPending send_pending: %x send_payload_pending:"
-			" %x smbd_send_pending: %x smbd_recv_pending: %x",
+		seq_printf(m, "\nPending send_pending: %x "
+			"send_payload_pending: %x",
 			atomic_read(&server->smbd_conn->send_pending),
-			atomic_read(&server->smbd_conn->send_payload_pending),
-			server->smbd_conn->smbd_send_pending,
-			server->smbd_conn->smbd_recv_pending);
+			atomic_read(&server->smbd_conn->send_payload_pending));
 		seq_printf(m, "\nReceive buffers count_receive_queue: %x "
 			"count_empty_packet_queue: %x",
 			server->smbd_conn->count_receive_queue,
diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 06449cf..7259427 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -164,95 +164,6 @@ do {									\
 #define log_rdma_mr(level, fmt, args...) \
 		log_rdma(level, LOG_RDMA_MR, fmt, ##args)
 
-/*
- * Destroy the transport and related RDMA and memory resources
- * Need to go through all the pending counters and make sure on one is using
- * the transport while it is destroyed
- */
-static void smbd_destroy_rdma_work(struct work_struct *work)
-{
-	struct smbd_response *response;
-	struct smbd_connection *info =
-		container_of(work, struct smbd_connection, destroy_work);
-	unsigned long flags;
-
-	log_rdma_event(INFO, "destroying qp\n");
-	ib_drain_qp(info->id->qp);
-	rdma_destroy_qp(info->id);
-
-	/* Unblock all I/O waiting on the send queue */
-	wake_up_interruptible_all(&info->wait_send_queue);
-
-	log_rdma_event(INFO, "cancelling idle timer\n");
-	cancel_delayed_work_sync(&info->idle_timer_work);
-	log_rdma_event(INFO, "cancelling send immediate work\n");
-	cancel_delayed_work_sync(&info->send_immediate_work);
-
-	log_rdma_event(INFO, "wait for all send to finish\n");
-	wait_event(info->wait_smbd_send_pending,
-		info->smbd_send_pending == 0);
-
-	log_rdma_event(INFO, "wait for all recv to finish\n");
-	wake_up_interruptible(&info->wait_reassembly_queue);
-	wait_event(info->wait_smbd_recv_pending,
-		info->smbd_recv_pending == 0);
-
-	log_rdma_event(INFO, "wait for all send posted to IB to finish\n");
-	wait_event(info->wait_send_pending,
-		atomic_read(&info->send_pending) == 0);
-	wait_event(info->wait_send_payload_pending,
-		atomic_read(&info->send_payload_pending) == 0);
-
-	log_rdma_event(INFO, "freeing mr list\n");
-	wake_up_interruptible_all(&info->wait_mr);
-	wait_event(info->wait_for_mr_cleanup,
-		atomic_read(&info->mr_used_count) == 0);
-	destroy_mr_list(info);
-
-	/* It's not posssible for upper layer to get to reassembly */
-	log_rdma_event(INFO, "drain the reassembly queue\n");
-	do {
-		spin_lock_irqsave(&info->reassembly_queue_lock, flags);
-		response = _get_first_reassembly(info);
-		if (response) {
-			list_del(&response->list);
-			spin_unlock_irqrestore(
-				&info->reassembly_queue_lock, flags);
-			put_receive_buffer(info, response);
-		} else
-			spin_unlock_irqrestore(&info->reassembly_queue_lock, flags);
-	} while (response);
-
-	info->reassembly_data_length = 0;
-
-	log_rdma_event(INFO, "free receive buffers\n");
-	wait_event(info->wait_receive_queues,
-		info->count_receive_queue + info->count_empty_packet_queue
-			== info->receive_credit_max);
-	destroy_receive_buffers(info);
-
-	ib_free_cq(info->send_cq);
-	ib_free_cq(info->recv_cq);
-	ib_dealloc_pd(info->pd);
-	rdma_destroy_id(info->id);
-
-	/* free mempools */
-	mempool_destroy(info->request_mempool);
-	kmem_cache_destroy(info->request_cache);
-
-	mempool_destroy(info->response_mempool);
-	kmem_cache_destroy(info->response_cache);
-
-	info->transport_status = SMBD_DESTROYED;
-	wake_up_all(&info->wait_destroy);
-}
-
-static int smbd_process_disconnected(struct smbd_connection *info)
-{
-	schedule_work(&info->destroy_work);
-	return 0;
-}
-
 static void smbd_disconnect_rdma_work(struct work_struct *work)
 {
 	struct smbd_connection *info =
@@ -319,8 +230,7 @@ static int smbd_conn_upcall(
 		}
 
 		info->transport_status = SMBD_DISCONNECTED;
-		smbd_process_disconnected(info);
-		wake_up(&info->disconn_wait);
+		wake_up_interruptible(&info->disconn_wait);
 		wake_up_interruptible(&info->wait_reassembly_queue);
 		wake_up_interruptible_all(&info->wait_send_queue);
 		break;
@@ -1501,7 +1411,7 @@ void smbd_destroy(struct TCP_Server_Info *server)
 	if (info->transport_status != SMBD_DISCONNECTED) {
 		rdma_disconnect(server->smbd_conn->id);
 		log_rdma_event(INFO, "wait for transport being disconnected\n");
-		wait_event(
+		wait_event_interruptible(
 			info->disconn_wait,
 			info->transport_status == SMBD_DISCONNECTED);
 	}
@@ -1849,12 +1759,6 @@ static struct smbd_connection *_smbd_get_connection(
 	queue_delayed_work(info->workqueue, &info->idle_timer_work,
 		info->keep_alive_interval*HZ);
 
-	init_waitqueue_head(&info->wait_smbd_send_pending);
-	info->smbd_send_pending = 0;
-
-	init_waitqueue_head(&info->wait_smbd_recv_pending);
-	info->smbd_recv_pending = 0;
-
 	init_waitqueue_head(&info->wait_send_pending);
 	atomic_set(&info->send_pending, 0);
 
@@ -1862,7 +1766,6 @@ static struct smbd_connection *_smbd_get_connection(
 	atomic_set(&info->send_payload_pending, 0);
 
 	INIT_WORK(&info->disconnect_work, smbd_disconnect_rdma_work);
-	INIT_WORK(&info->destroy_work, smbd_destroy_rdma_work);
 	INIT_WORK(&info->recv_done_work, smbd_recv_done_work);
 	INIT_WORK(&info->post_send_credits_work, smbd_post_send_credits);
 	info->new_credits_offered = 0;
@@ -1956,11 +1859,6 @@ static int smbd_recv_buf(struct smbd_connection *info, char *buf,
 	int rc;
 
 again:
-	if (info->transport_status != SMBD_CONNECTED) {
-		log_read(ERR, "disconnected\n");
-		return -ENODEV;
-	}
-
 	/*
 	 * No need to hold the reassembly queue lock all the time as we are
 	 * the only one reading from the front of the queue. The transport
@@ -2076,6 +1974,11 @@ static int smbd_recv_buf(struct smbd_connection *info, char *buf,
 	if (rc)
 		return -ENODEV;
 
+	if (info->transport_status != SMBD_CONNECTED) {
+		log_read(ERR, "disconnected\n");
+		return 0;
+	}
+
 	goto again;
 }
 
@@ -2126,8 +2029,6 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
 	unsigned int to_read, page_offset;
 	int rc;
 
-	info->smbd_recv_pending++;
-
 	if (iov_iter_rw(&msg->msg_iter) == WRITE) {
 		/* It's a bug in upper layer to get there */
 		cifs_dbg(VFS, "CIFS: invalid msg iter dir %u\n",
@@ -2158,9 +2059,6 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
 	}
 
 out:
-	info->smbd_recv_pending--;
-	wake_up(&info->wait_smbd_recv_pending);
-
 	/* SMBDirect will read it all or nothing */
 	if (rc > 0)
 		msg->msg_iter.count = 0;
@@ -2186,7 +2084,6 @@ int smbd_send(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 	struct kvec *iov;
 	int rc;
 
-	info->smbd_send_pending++;
 	if (info->transport_status != SMBD_CONNECTED) {
 		rc = -ENODEV;
 		goto done;
@@ -2342,9 +2239,6 @@ int smbd_send(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 	wait_event(info->wait_send_payload_pending,
 		atomic_read(&info->send_payload_pending) == 0);
 
-	info->smbd_send_pending--;
-	wake_up(&info->wait_smbd_send_pending);
-
 	return rc;
 }
 
diff --git a/fs/cifs/smbdirect.h b/fs/cifs/smbdirect.h
index 73cc923..a3c7b3d 100644
--- a/fs/cifs/smbdirect.h
+++ b/fs/cifs/smbdirect.h
@@ -70,13 +70,11 @@ struct smbd_connection {
 	int ri_rc;
 	struct completion ri_done;
 	wait_queue_head_t conn_wait;
-	wait_queue_head_t wait_destroy;
 	wait_queue_head_t disconn_wait;
 
 	struct completion negotiate_completion;
 	bool negotiate_done;
 
-	struct work_struct destroy_work;
 	struct work_struct disconnect_work;
 	struct work_struct recv_done_work;
 	struct work_struct post_send_credits_work;
@@ -124,13 +122,6 @@ struct smbd_connection {
 	wait_queue_head_t wait_for_mr_cleanup;
 
 	/* Activity accoutning */
-	/* Pending reqeusts issued from upper layer */
-	int smbd_send_pending;
-	wait_queue_head_t wait_smbd_send_pending;
-
-	int smbd_recv_pending;
-	wait_queue_head_t wait_smbd_recv_pending;
-
 	atomic_t send_pending;
 	wait_queue_head_t wait_send_pending;
 	atomic_t send_payload_pending;
-- 
2.7.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [Patch (resend) 2/5] cifs: smbd: Return EINTR when interrupted
  2019-04-05 21:36 [Patch (resend) 1/5] cifs: smbd: Don't destroy transport on RDMA disconnect Long Li
@ 2019-04-05 21:36 ` Long Li
  2019-04-05 21:36 ` [Patch (resend) 3/5] cifs: smbd: Indicate to retry on transport sending failure Long Li
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 7+ messages in thread
From: Long Li @ 2019-04-05 21:36 UTC (permalink / raw)
  To: Steve French, linux-cifs, samba-technical, linux-kernel; +Cc: Long Li

From: Long Li <longli@microsoft.com>

When packets are waiting for outbound I/O and interrupted, return the
proper error code to user process.

Signed-off-by: Long Li <longli@microsoft.com>
---
 fs/cifs/smbdirect.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 7259427..df95c75 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -1972,7 +1972,7 @@ static int smbd_recv_buf(struct smbd_connection *info, char *buf,
 			info->transport_status != SMBD_CONNECTED);
 	/* Don't return any data if interrupted */
 	if (rc)
-		return -ENODEV;
+		return rc;
 
 	if (info->transport_status != SMBD_CONNECTED) {
 		log_read(ERR, "disconnected\n");
-- 
2.7.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [Patch (resend) 3/5] cifs: smbd: Indicate to retry on transport sending failure
  2019-04-05 21:36 [Patch (resend) 1/5] cifs: smbd: Don't destroy transport on RDMA disconnect Long Li
  2019-04-05 21:36 ` [Patch (resend) 2/5] cifs: smbd: Return EINTR when interrupted Long Li
@ 2019-04-05 21:36 ` Long Li
  2019-04-05 21:36 ` [Patch (resend) 4/5] cifs: smbd: Retry on memory registration failure Long Li
  2019-04-05 21:36 ` [Patch (resend) 5/5] cifs: Call MID callback before destroying transport Long Li
  3 siblings, 0 replies; 7+ messages in thread
From: Long Li @ 2019-04-05 21:36 UTC (permalink / raw)
  To: Steve French, linux-cifs, samba-technical, linux-kernel; +Cc: Long Li

From: Long Li <longli@microsoft.com>

Failure to send a packet doesn't mean it's a permanent failure, it can't be
returned to user process. This I/O should be retried or failed based on
server packet response and transport health. This logic is handled by the
upper layer.

Give this decision to upper layer.

Signed-off-by: Long Li <longli@microsoft.com>
---
 fs/cifs/smbdirect.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index df95c75..05b05e7 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -853,7 +853,7 @@ static int smbd_create_header(struct smbd_connection *info,
 
 	if (info->transport_status != SMBD_CONNECTED) {
 		log_outgoing(ERR, "disconnected not sending\n");
-		return -ENOENT;
+		return -EAGAIN;
 	}
 	atomic_dec(&info->send_credits);
 
@@ -979,6 +979,7 @@ static int smbd_post_send(struct smbd_connection *info,
 				wake_up(&info->wait_send_pending);
 		}
 		smbd_disconnect_rdma_connection(info);
+		rc = -EAGAIN;
 	} else
 		/* Reset timer for idle connection after packet is sent */
 		mod_delayed_work(info->workqueue, &info->idle_timer_work,
@@ -2085,7 +2086,7 @@ int smbd_send(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 	int rc;
 
 	if (info->transport_status != SMBD_CONNECTED) {
-		rc = -ENODEV;
+		rc = -EAGAIN;
 		goto done;
 	}
 
-- 
2.7.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [Patch (resend) 4/5] cifs: smbd: Retry on memory registration failure
  2019-04-05 21:36 [Patch (resend) 1/5] cifs: smbd: Don't destroy transport on RDMA disconnect Long Li
  2019-04-05 21:36 ` [Patch (resend) 2/5] cifs: smbd: Return EINTR when interrupted Long Li
  2019-04-05 21:36 ` [Patch (resend) 3/5] cifs: smbd: Indicate to retry on transport sending failure Long Li
@ 2019-04-05 21:36 ` Long Li
  2019-04-05 21:36 ` [Patch (resend) 5/5] cifs: Call MID callback before destroying transport Long Li
  3 siblings, 0 replies; 7+ messages in thread
From: Long Li @ 2019-04-05 21:36 UTC (permalink / raw)
  To: Steve French, linux-cifs, samba-technical, linux-kernel; +Cc: Long Li

From: Long Li <longli@microsoft.com>

Memory registration failure doesn't mean this I/O has failed, it means the
transport is hitting I/O error or needs reconnect. This error is not from
the server.

Indicate this error to upper layer, and let upper layer decide how to
reconnect and proceed with this I/O.

Signed-off-by: Long Li <longli@microsoft.com>
---
 fs/cifs/smb2pdu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 21ad01d..ff3b730 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3220,7 +3220,7 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
 				rdata->nr_pages, rdata->page_offset,
 				rdata->tailsz, true, need_invalidate);
 		if (!rdata->mr)
-			return -ENOBUFS;
+			return -EAGAIN;
 
 		req->Channel = SMB2_CHANNEL_RDMA_V1_INVALIDATE;
 		if (need_invalidate)
@@ -3624,7 +3624,7 @@ smb2_async_writev(struct cifs_writedata *wdata,
 				wdata->nr_pages, wdata->page_offset,
 				wdata->tailsz, false, need_invalidate);
 		if (!wdata->mr) {
-			rc = -ENOBUFS;
+			rc = -EAGAIN;
 			goto async_writev_out;
 		}
 		req->Length = 0;
-- 
2.7.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [Patch (resend) 5/5] cifs: Call MID callback before destroying transport
  2019-04-05 21:36 [Patch (resend) 1/5] cifs: smbd: Don't destroy transport on RDMA disconnect Long Li
                   ` (2 preceding siblings ...)
  2019-04-05 21:36 ` [Patch (resend) 4/5] cifs: smbd: Retry on memory registration failure Long Li
@ 2019-04-05 21:36 ` Long Li
  2019-05-09 18:00   ` Pavel Shilovsky
  3 siblings, 1 reply; 7+ messages in thread
From: Long Li @ 2019-04-05 21:36 UTC (permalink / raw)
  To: Steve French, linux-cifs, samba-technical, linux-kernel; +Cc: Long Li

From: Long Li <longli@microsoft.com>

When transport is being destroyed, it's possible that some processes may
hold memory registrations that need to be deregistred.

Call them first so nobody is using transport resources, and it can be
destroyed.

Signed-off-by: Long Li <longli@microsoft.com>
---
 fs/cifs/connect.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 33e4d98..084756cf 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -528,22 +528,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
 	/* do not want to be sending data on a socket we are freeing */
 	cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
 	mutex_lock(&server->srv_mutex);
-	if (server->ssocket) {
-		cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
-			 server->ssocket->state, server->ssocket->flags);
-		kernel_sock_shutdown(server->ssocket, SHUT_WR);
-		cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n",
-			 server->ssocket->state, server->ssocket->flags);
-		sock_release(server->ssocket);
-		server->ssocket = NULL;
-	} else if (cifs_rdma_enabled(server))
-		smbd_destroy(server);
-	server->sequence_number = 0;
-	server->session_estab = false;
-	kfree(server->session_key.response);
-	server->session_key.response = NULL;
-	server->session_key.len = 0;
-	server->lstrp = jiffies;
 
 	/* mark submitted MIDs for retry and issue callback */
 	INIT_LIST_HEAD(&retry_list);
@@ -556,7 +540,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
 		list_move(&mid_entry->qhead, &retry_list);
 	}
 	spin_unlock(&GlobalMid_Lock);
-	mutex_unlock(&server->srv_mutex);
 
 	cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
 	list_for_each_safe(tmp, tmp2, &retry_list) {
@@ -565,6 +548,25 @@ cifs_reconnect(struct TCP_Server_Info *server)
 		mid_entry->callback(mid_entry);
 	}
 
+	if (server->ssocket) {
+		cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
+			 server->ssocket->state, server->ssocket->flags);
+		kernel_sock_shutdown(server->ssocket, SHUT_WR);
+		cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n",
+			 server->ssocket->state, server->ssocket->flags);
+		sock_release(server->ssocket);
+		server->ssocket = NULL;
+	} else if (cifs_rdma_enabled(server))
+		smbd_destroy(server);
+	server->sequence_number = 0;
+	server->session_estab = false;
+	kfree(server->session_key.response);
+	server->session_key.response = NULL;
+	server->session_key.len = 0;
+	server->lstrp = jiffies;
+
+	mutex_unlock(&server->srv_mutex);
+
 	do {
 		try_to_freeze();
 
-- 
2.7.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [Patch (resend) 5/5] cifs: Call MID callback before destroying transport
  2019-04-05 21:36 ` [Patch (resend) 5/5] cifs: Call MID callback before destroying transport Long Li
@ 2019-05-09 18:00   ` Pavel Shilovsky
  2019-05-14  1:32     ` Long Li
  0 siblings, 1 reply; 7+ messages in thread
From: Pavel Shilovsky @ 2019-05-09 18:00 UTC (permalink / raw)
  To: Long Li; +Cc: Steve French, linux-cifs, samba-technical, Kernel Mailing List

пт, 5 апр. 2019 г. в 14:39, Long Li <longli@linuxonhyperv.com>:
>
> From: Long Li <longli@microsoft.com>
>
> When transport is being destroyed, it's possible that some processes may
> hold memory registrations that need to be deregistred.
>
> Call them first so nobody is using transport resources, and it can be
> destroyed.
>
> Signed-off-by: Long Li <longli@microsoft.com>
> ---
>  fs/cifs/connect.c | 36 +++++++++++++++++++-----------------
>  1 file changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 33e4d98..084756cf 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -528,22 +528,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
>         /* do not want to be sending data on a socket we are freeing */
>         cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
>         mutex_lock(&server->srv_mutex);
> -       if (server->ssocket) {
> -               cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
> -                        server->ssocket->state, server->ssocket->flags);
> -               kernel_sock_shutdown(server->ssocket, SHUT_WR);
> -               cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n",
> -                        server->ssocket->state, server->ssocket->flags);
> -               sock_release(server->ssocket);
> -               server->ssocket = NULL;
> -       } else if (cifs_rdma_enabled(server))
> -               smbd_destroy(server);
> -       server->sequence_number = 0;
> -       server->session_estab = false;
> -       kfree(server->session_key.response);
> -       server->session_key.response = NULL;
> -       server->session_key.len = 0;
> -       server->lstrp = jiffies;
>
>         /* mark submitted MIDs for retry and issue callback */
>         INIT_LIST_HEAD(&retry_list);
> @@ -556,7 +540,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
>                 list_move(&mid_entry->qhead, &retry_list);
>         }
>         spin_unlock(&GlobalMid_Lock);
> -       mutex_unlock(&server->srv_mutex);
>
>         cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
>         list_for_each_safe(tmp, tmp2, &retry_list) {
> @@ -565,6 +548,25 @@ cifs_reconnect(struct TCP_Server_Info *server)
>                 mid_entry->callback(mid_entry);
>         }

The original call was issuing callbacks without holding srv_mutex -
callbacks may take this mutex for its internal needs. With the
proposed patch the code will deadlock.

Also the idea of destroying the socket first is to allow possible
retries (from callbacks) to return a proper error instead of trying to
send anything through the reconnecting socket.

>
> +       if (server->ssocket) {
> +               cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
> +                        server->ssocket->state, server->ssocket->flags);
> +               kernel_sock_shutdown(server->ssocket, SHUT_WR);
> +               cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n",
> +                        server->ssocket->state, server->ssocket->flags);
> +               sock_release(server->ssocket);
> +               server->ssocket = NULL;
> +       } else if (cifs_rdma_enabled(server))
> +               smbd_destroy(server);

If we need to call smbd_destroy() *after* callbacks, let's just move
it alone without the rest of the code.


> +       server->sequence_number = 0;
> +       server->session_estab = false;
> +       kfree(server->session_key.response);
> +       server->session_key.response = NULL;
> +       server->session_key.len = 0;
> +       server->lstrp = jiffies;
> +
> +       mutex_unlock(&server->srv_mutex);
> +
>         do {
>                 try_to_freeze();
>
> --
> 2.7.4
>


--
Best regards,
Pavel Shilovsky

^ permalink raw reply	[flat|nested] 7+ messages in thread

* RE: [Patch (resend) 5/5] cifs: Call MID callback before destroying transport
  2019-05-09 18:00   ` Pavel Shilovsky
@ 2019-05-14  1:32     ` Long Li
  0 siblings, 0 replies; 7+ messages in thread
From: Long Li @ 2019-05-14  1:32 UTC (permalink / raw)
  To: Pavel Shilovsky
  Cc: Steve French, linux-cifs, samba-technical, Kernel Mailing List

>>>-----Original Message-----
>>>From: Pavel Shilovsky <piastryyy@gmail.com>
>>>Sent: Thursday, May 9, 2019 11:01 AM
>>>To: Long Li <longli@microsoft.com>
>>>Cc: Steve French <sfrench@samba.org>; linux-cifs <linux-
>>>cifs@vger.kernel.org>; samba-technical <samba-technical@lists.samba.org>;
>>>Kernel Mailing List <linux-kernel@vger.kernel.org>
>>>Subject: Re: [Patch (resend) 5/5] cifs: Call MID callback before destroying
>>>transport
>>>
>>>пт, 5 апр. 2019 г. в 14:39, Long Li <longli@linuxonhyperv.com>:
>>>>
>>>> From: Long Li <longli@microsoft.com>
>>>>
>>>> When transport is being destroyed, it's possible that some processes
>>>> may hold memory registrations that need to be deregistred.
>>>>
>>>> Call them first so nobody is using transport resources, and it can be
>>>> destroyed.
>>>>
>>>> Signed-off-by: Long Li <longli@microsoft.com>
>>>> ---
>>>>  fs/cifs/connect.c | 36 +++++++++++++++++++-----------------
>>>>  1 file changed, 19 insertions(+), 17 deletions(-)
>>>>
>>>> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index
>>>> 33e4d98..084756cf 100644
>>>> --- a/fs/cifs/connect.c
>>>> +++ b/fs/cifs/connect.c
>>>> @@ -528,22 +528,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
>>>>         /* do not want to be sending data on a socket we are freeing */
>>>>         cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
>>>>         mutex_lock(&server->srv_mutex);
>>>> -       if (server->ssocket) {
>>>> -               cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
>>>> -                        server->ssocket->state, server->ssocket->flags);
>>>> -               kernel_sock_shutdown(server->ssocket, SHUT_WR);
>>>> -               cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n",
>>>> -                        server->ssocket->state, server->ssocket->flags);
>>>> -               sock_release(server->ssocket);
>>>> -               server->ssocket = NULL;
>>>> -       } else if (cifs_rdma_enabled(server))
>>>> -               smbd_destroy(server);
>>>> -       server->sequence_number = 0;
>>>> -       server->session_estab = false;
>>>> -       kfree(server->session_key.response);
>>>> -       server->session_key.response = NULL;
>>>> -       server->session_key.len = 0;
>>>> -       server->lstrp = jiffies;
>>>>
>>>>         /* mark submitted MIDs for retry and issue callback */
>>>>         INIT_LIST_HEAD(&retry_list);
>>>> @@ -556,7 +540,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
>>>>                 list_move(&mid_entry->qhead, &retry_list);
>>>>         }
>>>>         spin_unlock(&GlobalMid_Lock);
>>>> -       mutex_unlock(&server->srv_mutex);
>>>>
>>>>         cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
>>>>         list_for_each_safe(tmp, tmp2, &retry_list) { @@ -565,6 +548,25
>>>> @@ cifs_reconnect(struct TCP_Server_Info *server)
>>>>                 mid_entry->callback(mid_entry);
>>>>         }
>>>
>>>The original call was issuing callbacks without holding srv_mutex - callbacks
>>>may take this mutex for its internal needs. With the proposed patch the
>>>code will deadlock.
>>>
>>>Also the idea of destroying the socket first is to allow possible retries (from
>>>callbacks) to return a proper error instead of trying to send anything through
>>>the reconnecting socket.

I will send a patch to revert this and follow your suggestion on putting smbd_destroy() to after all MIDs have been called. Your suggestion tested well.

Thanks

Long

>>>
>>>>
>>>> +       if (server->ssocket) {
>>>> +               cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
>>>> +                        server->ssocket->state, server->ssocket->flags);
>>>> +               kernel_sock_shutdown(server->ssocket, SHUT_WR);
>>>> +               cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n",
>>>> +                        server->ssocket->state, server->ssocket->flags);
>>>> +               sock_release(server->ssocket);
>>>> +               server->ssocket = NULL;
>>>> +       } else if (cifs_rdma_enabled(server))
>>>> +               smbd_destroy(server);
>>>
>>>If we need to call smbd_destroy() *after* callbacks, let's just move it alone
>>>without the rest of the code.
>>>
>>>
>>>> +       server->sequence_number = 0;
>>>> +       server->session_estab = false;
>>>> +       kfree(server->session_key.response);
>>>> +       server->session_key.response = NULL;
>>>> +       server->session_key.len = 0;
>>>> +       server->lstrp = jiffies;
>>>> +
>>>> +       mutex_unlock(&server->srv_mutex);
>>>> +
>>>>         do {
>>>>                 try_to_freeze();
>>>>
>>>> --
>>>> 2.7.4
>>>>
>>>
>>>
>>>--
>>>Best regards,
>>>Pavel Shilovsky

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2019-05-14  1:32 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-05 21:36 [Patch (resend) 1/5] cifs: smbd: Don't destroy transport on RDMA disconnect Long Li
2019-04-05 21:36 ` [Patch (resend) 2/5] cifs: smbd: Return EINTR when interrupted Long Li
2019-04-05 21:36 ` [Patch (resend) 3/5] cifs: smbd: Indicate to retry on transport sending failure Long Li
2019-04-05 21:36 ` [Patch (resend) 4/5] cifs: smbd: Retry on memory registration failure Long Li
2019-04-05 21:36 ` [Patch (resend) 5/5] cifs: Call MID callback before destroying transport Long Li
2019-05-09 18:00   ` Pavel Shilovsky
2019-05-14  1:32     ` Long Li

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