diff options
Diffstat (limited to 'net/sunrpc')
| -rw-r--r-- | net/sunrpc/clnt.c | 107 |
1 files changed, 100 insertions, 7 deletions
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 587f31e0577e..f167d9c8d7dd 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -25,6 +25,7 @@ #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> @@ -264,6 +265,25 @@ void rpc_clients_notifier_unregister(void) return rpc_pipefs_notifier_unregister(&rpc_clients_block); } +static struct rpc_xprt *rpc_clnt_set_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); + + return old; +} + static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename) { clnt->cl_nodelen = strlen(nodename); @@ -338,7 +358,8 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, { const struct rpc_program *program = args->program; const struct rpc_version *version; - struct rpc_clnt *clnt = NULL; + struct rpc_clnt *clnt = NULL; + const struct rpc_timeout *timeout; int err; /* sanity check the name before trying to print it */ @@ -366,7 +387,6 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, if (err) goto out_no_clid; - rcu_assign_pointer(clnt->cl_xprt, xprt); clnt->cl_procinfo = version->procs; clnt->cl_maxproc = version->nrprocs; clnt->cl_prog = args->prognumber ? : program->number; @@ -381,16 +401,15 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, 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_clnt_set_transport(clnt, xprt, timeout); + clnt->cl_rtt = &clnt->cl_rtt_default; rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval); @@ -601,6 +620,80 @@ rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor) } EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth); +/** + * 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 RPC tasks by using some form of locking. + * + * Returns zero if "clnt" is now using the new xprt. Otherwise a + * negative errno is returned, and "clnt" continues to use the old + * xprt. + */ +int rpc_switch_client_transport(struct rpc_clnt *clnt, + struct xprt_create *args, + const struct rpc_timeout *timeout) +{ + const struct rpc_timeout *old_timeo; + rpc_authflavor_t pseudoflavor; + struct rpc_xprt *xprt, *old; + struct rpc_clnt *parent; + int err; + + xprt = xprt_create_transport(args); + if (IS_ERR(xprt)) { + dprintk("RPC: failed to create new xprt for clnt %p\n", + clnt); + return PTR_ERR(xprt); + } + + pseudoflavor = clnt->cl_auth->au_flavor; + + old_timeo = clnt->cl_timeout; + old = rpc_clnt_set_transport(clnt, xprt, timeout); + + rpc_unregister_client(clnt); + __rpc_clnt_remove_pipedir(clnt); + + /* + * A new transport was created. "clnt" therefore + * becomes the root of a new cl_parent tree. clnt's + * children, if it has any, still point to the old xprt. + */ + parent = clnt->cl_parent; + clnt->cl_parent = clnt; + + /* + * The old rpc_auth cache cannot be re-used. GSS + * contexts in particular are between a single + * client and server. + */ + err = rpc_client_register(clnt, pseudoflavor, NULL); + if (err) + goto out_revert; + + synchronize_rcu(); + if (parent != clnt) + rpc_release_client(parent); + xprt_put(old); + dprintk("RPC: replaced xprt for clnt %p\n", clnt); + return 0; + +out_revert: + rpc_clnt_set_transport(clnt, old, old_timeo); + clnt->cl_parent = parent; + rpc_client_register(clnt, pseudoflavor, NULL); + xprt_put(xprt); + dprintk("RPC: failed to switch xprt for clnt %p\n", clnt); + return err; +} +EXPORT_SYMBOL_GPL(rpc_switch_client_transport); + /* * Kill all tasks for the given client. * XXX: kill their descendants as well? |