lockd: Use xdrgen XDR functions for the NLMv4 LOCK_MSG procedure

The LOCK_MSG procedure is part of NLM's asynchronous lock
request flow, where clients send LOCK_MSG to request locks
that may block. This patch continues the xdrgen migration by
converting LOCK_MSG to use generated XDR functions.

This patch converts the LOCK_MSG procedure to use xdrgen
functions nlm4_svc_decode_nlm4_lockargs and
nlm4_svc_encode_void generated from the NLM version 4
protocol specification. The procedure handler uses xdrgen
types through the nlm4_lockargs_wrapper structure that
bridges between generated code and the legacy nlm_lock
representation.

The pc_argzero field is set to zero because xdrgen decoders
reliably initialize all arguments in the argp->xdrgen field,
making the early defensive memset unnecessary. Remaining
argp fields are cleared as needed.

The NLM async callback mechanism uses client-side functions
which continue to take legacy results like struct nlm_res,
preventing LOCK and LOCK_MSG from sharing code for now.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
index afce778b62d3df5b2d66b8d707a0262b253b37b7..d9406a4ab1761e5485db00945e1fa49e17cf7b26 100644 (file)
--- a/fs/lockd/svc4proc.c
+++ b/fs/lockd/svc4proc.c
@@ -812,19 +812,64 @@ static __be32 nlm4svc_proc_test_msg(struct svc_rqst *rqstp)
                                __nlm4svc_proc_test_msg);
 }
 
-static __be32 nlm4svc_proc_lock_msg(struct svc_rqst *rqstp)
+static __be32
+__nlm4svc_proc_lock_msg(struct svc_rqst *rqstp, struct nlm_res *resp)
 {
-       struct nlm_args *argp = rqstp->rq_argp;
-       struct nlm_host *host;
+       struct nlm4_lockargs_wrapper *argp = rqstp->rq_argp;
+       unsigned char type = argp->xdrgen.exclusive ? F_WRLCK : F_RDLCK;
+       struct nlm_file *file = NULL;
+       struct nlm_host *host = NULL;
 
-       dprintk("lockd: LOCK_MSG      called\n");
+       resp->status = nlm_lck_denied_nolocks;
+       if (nlm4_netobj_to_cookie(&resp->cookie, &argp->xdrgen.cookie))
+               goto out;
 
-       host = nlmsvc_lookup_host(rqstp, argp->lock.caller, argp->lock.len);
+       host = nlm4svc_lookup_host(rqstp, argp->xdrgen.alock.caller_name, true);
+       if (!host)
+               goto out;
+
+       resp->status = nlm4svc_lookup_file(rqstp, host, &argp->lock,
+                                          &file, &argp->xdrgen.alock, type);
+       if (resp->status)
+               goto out;
+
+       resp->status = nlmsvc_lock(rqstp, file, host, &argp->lock,
+                                  argp->xdrgen.block, &resp->cookie,
+                                  argp->xdrgen.reclaim);
+       nlmsvc_release_lockowner(&argp->lock);
+
+out:
+       if (file)
+               nlm_release_file(file);
+       nlmsvc_release_host(host);
+       return resp->status == nlm__int__drop_reply ?
+               rpc_drop_reply : rpc_success;
+}
+
+/**
+ * nlm4svc_proc_lock_msg - LOCK_MSG: Establish a monitored lock
+ * @rqstp: RPC transaction context
+ *
+ * Returns:
+ *   %rpc_success:             RPC executed successfully.
+ *   %rpc_system_err:          RPC execution failed.
+ *
+ * RPC synopsis:
+ *   void NLMPROC4_LOCK_MSG(nlm4_lockargs) = 7;
+ *
+ * The response to this request is delivered via the LOCK_RES procedure.
+ */
+static __be32 nlm4svc_proc_lock_msg(struct svc_rqst *rqstp)
+{
+       struct nlm4_lockargs_wrapper *argp = rqstp->rq_argp;
+       struct nlm_host *host;
+
+       host = nlm4svc_lookup_host(rqstp, argp->xdrgen.alock.caller_name, true);
        if (!host)
                return rpc_system_err;
 
-       return nlm4svc_callback(rqstp, host, NLMPROC_LOCK_RES,
-                               __nlm4svc_proc_lock);
+       return nlm4svc_callback(rqstp, host, NLMPROC4_LOCK_RES,
+                               __nlm4svc_proc_lock_msg);
 }
 
 static __be32 nlm4svc_proc_cancel_msg(struct svc_rqst *rqstp)
@@ -1103,15 +1148,15 @@ static const struct svc_procedure nlm4svc_procedures[24] = {
                .pc_xdrressize  = XDR_void,
                .pc_name        = "TEST_MSG",
        },
-       [NLMPROC_LOCK_MSG] = {
-               .pc_func = nlm4svc_proc_lock_msg,
-               .pc_decode = nlm4svc_decode_lockargs,
-               .pc_encode = nlm4svc_encode_void,
-               .pc_argsize = sizeof(struct nlm_args),
-               .pc_argzero = sizeof(struct nlm_args),
-               .pc_ressize = sizeof(struct nlm_void),
-               .pc_xdrressize = St,
-               .pc_name = "LOCK_MSG",
+       [NLMPROC4_LOCK_MSG] = {
+               .pc_func        = nlm4svc_proc_lock_msg,
+               .pc_decode      = nlm4_svc_decode_nlm4_lockargs,
+               .pc_encode      = nlm4_svc_encode_void,
+               .pc_argsize     = sizeof(struct nlm4_lockargs_wrapper),
+               .pc_argzero     = 0,
+               .pc_ressize     = 0,
+               .pc_xdrressize  = XDR_void,
+               .pc_name        = "LOCK_MSG",
        },
        [NLMPROC_CANCEL_MSG] = {
                .pc_func = nlm4svc_proc_cancel_msg,