lockd: Use xdrgen XDR functions for the NLMv3 TEST_MSG procedure

Continue the xdrgen migration by converting NLMv3 TEST_MSG, the
async counterpart to TEST that clients use to check lock
availability without blocking. 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 nlm3svc_lookup_file() 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 TEST and TEST_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/svcproc.c b/fs/lockd/svcproc.c
index 2e6afb9a19b907e10665a1b571e58ebbb5d8185b..cd32cfc623382251e5f64a03bdde794373ae4a0a 100644 (file)
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -296,40 +296,6 @@ static __be32 nlmsvc_proc_null(struct svc_rqst *rqstp)
        return rpc_success;
 }
 
-/*
- * TEST: Check for conflicting lock
- */
-static __be32
-__nlmsvc_proc_test(struct svc_rqst *rqstp, struct lockd_res *resp)
-{
-       struct lockd_args *argp = rqstp->rq_argp;
-       struct nlm_host *host;
-       struct nlm_file *file;
-       __be32 rc = rpc_success;
-
-       dprintk("lockd: TEST          called\n");
-       resp->cookie = argp->cookie;
-
-       /* Obtain client and file */
-       if ((resp->status = nlmsvc_retrieve_args(rqstp, argp, &host, &file)))
-               return resp->status == nlm__int__drop_reply ?
-                       rpc_drop_reply : rpc_success;
-
-       /* Now check for conflicting locks */
-       resp->status = cast_status(nlmsvc_testlock(rqstp, file, host,
-                                                  &argp->lock, &resp->lock));
-       if (resp->status == nlm__int__drop_reply)
-               rc = rpc_drop_reply;
-       else
-               dprintk("lockd: TEST          status %d vers %d\n",
-                       ntohl(resp->status), rqstp->rq_vers);
-
-       nlmsvc_release_lockowner(&argp->lock);
-       nlmsvc_release_host(host);
-       nlm_release_file(file);
-       return rc;
-}
-
 /**
  * nlmsvc_proc_test - TEST: Check for conflicting lock
  * @rqstp: RPC transaction context
@@ -805,19 +771,69 @@ nlmsvc_callback(struct svc_rqst *rqstp, struct nlm_host *host, u32 proc,
        return rpc_success;
 }
 
+static __be32
+__nlmsvc_proc_test_msg(struct svc_rqst *rqstp, struct lockd_res *resp)
+{
+       struct nlm_testargs_wrapper *argp = rqstp->rq_argp;
+       unsigned char type = argp->xdrgen.exclusive ? F_WRLCK : F_RDLCK;
+       struct nlm_lockowner *owner;
+       struct nlm_file *file = NULL;
+       struct nlm_host *host = NULL;
+
+       resp->status = nlm_lck_denied_nolocks;
+       if (nlm_netobj_to_cookie(&resp->cookie, &argp->xdrgen.cookie))
+               goto out;
+
+       host = nlm3svc_lookup_host(rqstp, argp->xdrgen.alock.caller_name, false);
+       if (!host)
+               goto out;
+
+       resp->status = nlm3svc_lookup_file(rqstp, host, &argp->lock,
+                                          &file, &argp->xdrgen.alock, type);
+       if (resp->status)
+               goto out;
+
+       owner = argp->lock.fl.c.flc_owner;
+       resp->status = cast_status(nlmsvc_testlock(rqstp, file, host,
+                                                  &argp->lock, &resp->lock));
+       nlmsvc_put_lockowner(owner);
+
+out:
+       if (file)
+               nlm_release_file(file);
+       nlmsvc_release_host(host);
+       return resp->status == nlm__int__drop_reply ? rpc_drop_reply : rpc_success;
+}
+
+/**
+ * nlmsvc_proc_test_msg - TEST_MSG: Check for conflicting lock
+ * @rqstp: RPC transaction context
+ *
+ * Returns:
+ *   %rpc_success:             RPC executed successfully.
+ *   %rpc_drop_reply:          Do not send an RPC reply.
+ *   %rpc_garbage_args:        The request arguments are malformed.
+ *   %rpc_system_err:          RPC execution failed.
+ *
+ * RPC synopsis:
+ *   void NLMPROC_TEST_MSG(nlm_testargs) = 6;
+ *
+ * The response to this request is delivered via the TEST_RES procedure.
+ */
 static __be32 nlmsvc_proc_test_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: TEST_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_TEST_RES,
-                              __nlmsvc_proc_test);
+                              __nlmsvc_proc_test_msg);
 }
 
 static __be32 nlmsvc_proc_lock_msg(struct svc_rqst *rqstp)
@@ -1103,15 +1119,15 @@ static const struct svc_procedure nlmsvc_procedures[24] = {
                .pc_xdrressize  = NLM3_nlm_res_sz,
                .pc_name        = "GRANTED",
        },
-       [NLMPROC_TEST_MSG] = {
-               .pc_func = nlmsvc_proc_test_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 = "TEST_MSG",
+       [NLM_TEST_MSG] = {
+               .pc_func        = nlmsvc_proc_test_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        = "TEST_MSG",
        },
        [NLMPROC_LOCK_MSG] = {
                .pc_func = nlmsvc_proc_lock_msg,