lockd: Use xdrgen XDR functions for the NLMv3 GRANTED_MSG procedure

Continue the xdrgen migration by converting NLMv3 GRANTED_MSG,
the async counterpart to GRANTED that a remote NLM uses to tell
this lockd that a previously blocked client lock request has
become available. The procedure now uses
nlm_svc_decode_nlm_testargs and nlm_svc_encode_void, generated
from the NLM version 3 protocol specification. The procedure
handler reaches the xdrgen types through the
nlm_testargs_wrapper structure, which bridges between generated
code and the legacy lockd_lock representation.

Setting pc_argzero to zero is safe because the generated decoder
fills the argp->xdrgen subfields before the procedure runs, so
the zeroing memset performed by the dispatch layer is not
needed. The lock member of the wrapper is populated explicitly
in __nlmsvc_proc_granted_msg() by nlm_lock_to_lockd_lock()
rather than relying on zero-initialization.

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

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

1 files changed, 47 insertions, 31 deletions

diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index d059accfdebd..21a363450d59 100644
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -594,23 +594,6 @@ out:
 		rpc_drop_reply : rpc_success;
 }
 
-/*
- * GRANTED: A server calls us to tell that a process' lock request
- * was granted
- */
-static __be32
-__nlmsvc_proc_granted(struct svc_rqst *rqstp, struct lockd_res *resp)
-{
-	struct lockd_args *argp = rqstp->rq_argp;
-
-	resp->cookie = argp->cookie;
-
-	dprintk("lockd: GRANTED       called\n");
-	resp->status = nlmclnt_grant(svc_addr(rqstp), &argp->lock);
-	dprintk("lockd: GRANTED       status %d\n", ntohl(resp->status));
-	return rpc_success;
-}
-
 /**
  * nlmsvc_proc_granted - GRANTED: Blocked lock has been granted
  * @rqstp: RPC transaction context
@@ -966,19 +949,52 @@ static __be32 nlmsvc_proc_unlock_msg(struct svc_rqst *rqstp)
 			       __nlmsvc_proc_unlock_msg);
 }
 
+static __be32
+__nlmsvc_proc_granted_msg(struct svc_rqst *rqstp, struct lockd_res *resp)
+{
+	struct nlm_testargs_wrapper *argp = rqstp->rq_argp;
+
+	resp->status = nlm_lck_denied;
+	if (nlm_netobj_to_cookie(&resp->cookie, &argp->xdrgen.cookie))
+		goto out;
+
+	if (nlm_lock_to_lockd_lock(&argp->lock, &argp->xdrgen.alock))
+		goto out;
+
+	resp->status = nlmclnt_grant(svc_addr(rqstp), &argp->lock);
+
+out:
+	return rpc_success;
+}
+
+/**
+ * nlmsvc_proc_granted_msg - GRANTED_MSG: Blocked lock has been granted
+ * @rqstp: RPC transaction context
+ *
+ * Returns:
+ *   %rpc_success:		RPC executed successfully.
+ *   %rpc_garbage_args:	The request arguments are malformed.
+ *   %rpc_system_err:		RPC execution failed.
+ *
+ * RPC synopsis:
+ *   void NLMPROC_GRANTED_MSG(nlm_testargs) = 10;
+ *
+ * The response to this request is delivered via the GRANTED_RES procedure.
+ */
 static __be32 nlmsvc_proc_granted_msg(struct svc_rqst *rqstp)
 {
-	struct lockd_args *argp = rqstp->rq_argp;
-	struct nlm_host	*host;
+	struct nlm_testargs_wrapper *argp = rqstp->rq_argp;
+	struct nlm_host *host;
 
-	dprintk("lockd: GRANTED_MSG   called\n");
+	if (argp->xdrgen.cookie.len > NLM_MAXCOOKIELEN)
+		return rpc_garbage_args;
 
-	host = nlmsvc_lookup_host(rqstp, argp->lock.caller, argp->lock.len);
+	host = nlm3svc_lookup_host(rqstp, argp->xdrgen.alock.caller_name, false);
 	if (!host)
 		return rpc_system_err;
 
 	return nlmsvc_callback(rqstp, host, NLMPROC_GRANTED_RES,
-			       __nlmsvc_proc_granted);
+			       __nlmsvc_proc_granted_msg);
 }
 
 /*
@@ -1244,15 +1260,15 @@ static const struct svc_procedure nlmsvc_procedures[24] = {
 		.pc_xdrressize	= XDR_void,
 		.pc_name	= "UNLOCK_MSG",
 	},
-	[NLMPROC_GRANTED_MSG] = {
-		.pc_func = nlmsvc_proc_granted_msg,
-		.pc_decode = nlmsvc_decode_testargs,
-		.pc_encode = nlmsvc_encode_void,
-		.pc_argsize = sizeof(struct lockd_args),
-		.pc_argzero = sizeof(struct lockd_args),
-		.pc_ressize = sizeof(struct nlm_void),
-		.pc_xdrressize = St,
-		.pc_name = "GRANTED_MSG",
+	[NLM_GRANTED_MSG] = {
+		.pc_func	= nlmsvc_proc_granted_msg,
+		.pc_decode	= nlm_svc_decode_nlm_testargs,
+		.pc_encode	= nlm_svc_encode_void,
+		.pc_argsize	= sizeof(struct nlm_testargs_wrapper),
+		.pc_argzero	= 0,
+		.pc_ressize	= 0,
+		.pc_xdrressize	= XDR_void,
+		.pc_name	= "GRANTED_MSG",
 	},
 	[NLMPROC_TEST_RES] = {
 		.pc_func = nlmsvc_proc_null,