From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
[ cel: fix whitespace ]
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/clnt.h | 3 ++
net/sunrpc/clnt.c | 76 ++++++++++++++++++++++++++++++++++++++++---
2 files changed, 73 insertions(+), 6 deletions(-)
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 2eea0d7..d18d952 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -144,6 +144,9 @@ void rpc_task_release_client(struct rpc_task *);
int rpc_lock_client(struct rpc_clnt *clnt, unsigned long timeout);
void rpc_unlock_client(struct rpc_clnt *clnt);
+int rpc_switch_client_transport(struct rpc_clnt *,
+ struct xprt_create *,
+ const struct rpc_timeout *);
int rpcb_register(u32, u32, int, unsigned short);
int rpcb_v4_register(const u32 program, const u32 version,
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 6479e1d..ac2d29e 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -26,6 +26,7 @@
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/slab.h>
+#include <linux/rcupdate.h>
#include <linux/utsname.h>
#include <linux/workqueue.h>
#include <linux/in.h>
@@ -143,12 +144,35 @@ err:
return error;
}
+static void rpc_set_client_transport(struct rpc_clnt *clnt,
+ struct rpc_xprt *xprt,
+ const struct rpc_timeout *timeout)
+{
+ struct rpc_xprt *old;
+
+ spin_lock(&clnt->cl_lock);
+ old = clnt->cl_xprt;
+
+ if (!xprt_bound(xprt))
+ clnt->cl_autobind = 1;
+
+ clnt->cl_timeout = timeout;
+ rcu_assign_pointer(clnt->cl_xprt, xprt);
+ spin_unlock(&clnt->cl_lock);
+
+ if (old != NULL) {
+ synchronize_rcu();
+ xprt_put(old);
+ }
+}
+
static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
{
struct rpc_program *program = args->program;
struct rpc_version *version;
struct rpc_clnt *clnt = NULL;
struct rpc_auth *auth;
+ const struct rpc_timeout *timeout;
int err;
/* sanity check the name before trying to print it */
@@ -174,7 +198,6 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
goto out_err;
clnt->cl_parent = clnt;
- rcu_assign_pointer(clnt->cl_xprt, xprt);
clnt->cl_procinfo = version->procs;
clnt->cl_maxproc = version->nrprocs;
clnt->cl_protname = program->name;
@@ -189,16 +212,15 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
INIT_LIST_HEAD(&clnt->cl_tasks);
spin_lock_init(&clnt->cl_lock);
- if (!xprt_bound(xprt))
- clnt->cl_autobind = 1;
-
- clnt->cl_timeout = xprt->timeout;
+ timeout = xprt->timeout;
if (args->timeout != NULL) {
memcpy(&clnt->cl_timeout_default, args->timeout,
sizeof(clnt->cl_timeout_default));
- clnt->cl_timeout = &clnt->cl_timeout_default;
+ timeout = &clnt->cl_timeout_default;
}
+ rpc_set_client_transport(clnt, xprt, timeout);
+
clnt->cl_rtt = &clnt->cl_rtt_default;
rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
clnt->cl_principal = NULL;
@@ -412,6 +434,48 @@ out_no_clnt:
}
EXPORT_SYMBOL_GPL(rpc_clone_client);
+/**
+ * rpc_switch_client_transport: switch the RPC transport on the fly
+ * @clnt: pointer to a struct rpc_clnt
+ * @args: pointer to the new transport arguments
+ * @timeout: pointer to the new timeout parameters
+ *
+ * This function allows the caller to switch the RPC transport for the
+ * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS server,
+ * for instance. It assumes that the caller has ensured that there are no
+ * active tasks by using some form of locking.
+ */
+int rpc_switch_client_transport(struct rpc_clnt *clnt,
+ struct xprt_create *args,
+ const struct rpc_timeout *timeout)
+{
+ struct rpc_xprt *xprt;
+ struct rpc_auth *auth;
+ rpc_authflavor_t pseudoflavor;
+
+ xprt = xprt_create_transport(args);
+ if (IS_ERR(xprt))
+ return PTR_ERR(xprt);
+
+ pseudoflavor = clnt->cl_auth->au_flavor;
+
+ rpc_set_client_transport(clnt, xprt, timeout);
+
+ /*
+ * Note: we must always create a new rpc_auth cache
+ * when switching to a different server! RPCSEC_GSS sessions
+ * in particular are between a single client and server,
+ * so we cannot reuse the sessions in the cache when we switch
+ * servers.
+ */
+ auth = rpcauth_create(pseudoflavor, clnt);
+ if (IS_ERR(auth))
+ return PTR_ERR(auth);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
+
/*
* Kill all tasks for the given client.
* XXX: kill their descendants as well?
--
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