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From: Benjamin Coddington <bcodding@redhat.com>
To: trond.myklebust@hammerspace.com,
	anna@kernel.org
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH v3 2/2] NFSv4.1: Use the nfs_client's rpc timeouts for backchannel
Date: Wed, 13 Dec 2023 14:49:29 -0500
Message-ID: <90c9365ad91e1eb0058b170fb332ea70ad554d8b.1702496910.git.bcodding@redhat.com>
In-Reply-To: <e28038fba1243f00b0dd66b7c5296a1e181645ea.1702496910.git.bcodding@redhat.com>
References: <e28038fba1243f00b0dd66b7c5296a1e181645ea.1702496910.git.bcodding@redhat.com>
Precedence: bulk
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For backchannel requests that lookup the appropriate nfs_client, use the
state-management rpc_clnt's rpc_timeout parameters for the backchannel's
response.  When the nfs_client cannot be found, fall back to using the
xprt's default timeout parameters.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/callback_proc.c         | 3 +++
 fs/nfs/callback_xdr.c          | 3 +++
 include/linux/sunrpc/bc_xprt.h | 3 ++-
 include/linux/sunrpc/sched.h   | 3 ++-
 include/linux/sunrpc/svc.h     | 1 +
 net/sunrpc/clnt.c              | 8 ++++++--
 net/sunrpc/svc.c               | 6 +++++-
 net/sunrpc/xprt.c              | 5 +++--
 8 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 96a4923080ae..8ce721eba383 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -504,6 +504,9 @@ __be32 nfs4_callback_sequence(void *argp, void *resp,
 	if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
 		goto out;
 
+	/* release in svc_process_bc */
+	refcount_inc(&clp->cl_rpcclient->cl_count);
+
 	tbl = &clp->cl_session->bc_slot_table;
 
 	/* Set up res before grabbing the spinlock */
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 321af81c456e..40a43d615b82 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -967,6 +967,9 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp)
 		nops--;
 	}
 
+	if (svc_is_backchannel(rqstp) && cps.clp)
+		rqstp->bc_rpc_clnt = cps.clp->cl_rpcclient;
+
 	*hdr_res.status = status;
 	*hdr_res.nops = htonl(nops);
 	nfs4_cb_free_slot(&cps);
diff --git a/include/linux/sunrpc/bc_xprt.h b/include/linux/sunrpc/bc_xprt.h
index db30a159f9d5..f22bf915dcf6 100644
--- a/include/linux/sunrpc/bc_xprt.h
+++ b/include/linux/sunrpc/bc_xprt.h
@@ -20,7 +20,8 @@
 #ifdef CONFIG_SUNRPC_BACKCHANNEL
 struct rpc_rqst *xprt_lookup_bc_request(struct rpc_xprt *xprt, __be32 xid);
 void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied);
-void xprt_init_bc_request(struct rpc_rqst *req, struct rpc_task *task);
+void xprt_init_bc_request(struct rpc_rqst *req, struct rpc_task *task,
+		const struct rpc_timeout *to);
 void xprt_free_bc_request(struct rpc_rqst *req);
 int xprt_setup_backchannel(struct rpc_xprt *, unsigned int min_reqs);
 void xprt_destroy_backchannel(struct rpc_xprt *, unsigned int max_reqs);
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 8ada7dc802d3..786c1d2e9d6a 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -205,7 +205,8 @@ struct rpc_wait_queue {
  */
 struct rpc_task *rpc_new_task(const struct rpc_task_setup *);
 struct rpc_task *rpc_run_task(const struct rpc_task_setup *);
-struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req);
+struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
+		struct rpc_clnt *clnt);
 void		rpc_put_task(struct rpc_task *);
 void		rpc_put_task_async(struct rpc_task *);
 bool		rpc_task_set_rpc_status(struct rpc_task *task, int rpc_status);
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index b10f987509cc..1c727a422a65 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -250,6 +250,7 @@ struct svc_rqst {
 	struct net		*rq_bc_net;	/* pointer to backchannel's
 						 * net namespace
 						 */
+	struct rpc_clnt		*bc_rpc_clnt;	/* v4.1 backchannel RPC client */
 	void **			rq_lease_breaker; /* The v4 client breaking a lease */
 	unsigned int		rq_status_counter; /* RPC processing counter */
 };
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index daa9582ec861..1946c2b39de3 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1302,9 +1302,12 @@ static void call_bc_encode(struct rpc_task *task);
  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
  * rpc_execute against it
  * @req: RPC request
+ * @clnt: RPC client from request's cl_rpcclient
  */
-struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req)
+struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
+		struct rpc_clnt *clnt)
 {
+	const struct rpc_timeout *timeout;
 	struct rpc_task *task;
 	struct rpc_task_setup task_setup_data = {
 		.callback_ops = &rpc_default_ops,
@@ -1322,7 +1325,8 @@ struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req)
 		return task;
 	}
 
-	xprt_init_bc_request(req, task);
+	timeout = clnt ? clnt->cl_timeout : req->rq_xprt->timeout;
+	xprt_init_bc_request(req, task, timeout);
 
 	task->tk_action = call_bc_encode;
 	atomic_inc(&task->tk_count);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 3f2ea7a0496f..47685c05499a 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1603,7 +1603,11 @@ void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp)
 	}
 	/* Finally, send the reply synchronously */
 	memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
-	task = rpc_run_bc_task(req);
+	task = rpc_run_bc_task(req, rqstp->bc_rpc_clnt);
+
+	if (rqstp->bc_rpc_clnt)
+		rpc_release_client(rqstp->bc_rpc_clnt);
+
 	if (IS_ERR(task))
 		return;
 
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 6cc9ffac962d..6f69975f3764 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1986,7 +1986,8 @@ void xprt_release(struct rpc_task *task)
 
 #ifdef CONFIG_SUNRPC_BACKCHANNEL
 void
-xprt_init_bc_request(struct rpc_rqst *req, struct rpc_task *task)
+xprt_init_bc_request(struct rpc_rqst *req, struct rpc_task *task,
+		const struct rpc_timeout *to)
 {
 	struct xdr_buf *xbufp = &req->rq_snd_buf;
 
@@ -2000,7 +2001,7 @@ xprt_init_bc_request(struct rpc_rqst *req, struct rpc_task *task)
 	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
 		xbufp->tail[0].iov_len;
 
-	xprt_init_majortimeo(task, req, req->rq_xprt->timeout);
+	xprt_init_majortimeo(task, req, to);
 }
 #endif
 
-- 
2.43.0