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lockd: Use xdrgen XDR functions for the NLMv3 CANCEL_MSG procedure

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The CANCEL_MSG procedure is part of NLM's asynchronous lock
request flow, where clients send CANCEL_MSG to cancel pending
lock requests. This patch continues the xdrgen migration by
converting CANCEL_MSG to use generated XDR functions.

This patch converts the CANCEL_MSG procedure to use xdrgen
functions nlm_svc_decode_nlm_cancargs and nlm_svc_encode_void
generated from the NLM version 3 protocol specification. The
procedure handler uses xdrgen types through the
nlm_cancargs_wrapper structure that 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 previous hand-written decoder in svcxdr_decode_cookie()
rewrote a zero-length NLM cookie into a four-byte zero cookie,
with a comment attributing the substitution to HP-UX clients.
The xdrgen-generated netobj decoder performs no such rewrite, so
a zero-length request cookie now round-trips unchanged into the
CANCEL_RES reply. HP-UX has reached end of support, and CANCEL_MSG
is fire-and-forget with no client-side reply matching on the NLM
cookie, so the workaround is dropped intentionally here.

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

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2026-05-12 14:13:57 -04:00 committed by Chuck Lever
parent 438c9af3b1
commit 02a47b6c5c
1 changed files with 67 additions and 47 deletions
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114
fs/lockd/svcproc.c
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@ -478,39 +478,6 @@ nlmsvc_proc_lock(struct svc_rqst *rqstp)
return nlmsvc_do_lock(rqstp, true);
}
static __be32
__nlmsvc_proc_cancel(struct svc_rqst *rqstp, struct lockd_res *resp)
{
struct lockd_args *argp = rqstp->rq_argp;
struct nlm_host *host;
struct nlm_file *file;
struct net *net = SVC_NET(rqstp);
dprintk("lockd: CANCEL called\n");
resp->cookie = argp->cookie;
/* Don't accept requests during grace period */
if (locks_in_grace(net)) {
resp->status = nlm_lck_denied_grace_period;
return rpc_success;
}
/* 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;
/* Try to cancel request. */
resp->status = cast_status(nlmsvc_cancel_blocked(net, file, &argp->lock));
dprintk("lockd: CANCEL status %d\n", ntohl(resp->status));
nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
}
/**
* nlmsvc_proc_cancel - CANCEL: Cancel an outstanding blocked lock request
* @rqstp: RPC transaction context
@ -900,19 +867,72 @@ static __be32 nlmsvc_proc_lock_msg(struct svc_rqst *rqstp)
__nlmsvc_proc_lock_msg);
}
static __be32
__nlmsvc_proc_cancel_msg(struct svc_rqst *rqstp, struct lockd_res *resp)
{
struct nlm_cancargs_wrapper *argp = rqstp->rq_argp;
unsigned char type = argp->xdrgen.exclusive ? F_WRLCK : F_RDLCK;
struct net *net = SVC_NET(rqstp);
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;
resp->status = nlm_lck_denied_grace_period;
if (locks_in_grace(net))
goto out;
resp->status = nlm_lck_denied_nolocks;
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;
resp->status = nlmsvc_cancel_blocked(net, file, &argp->lock);
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;
}
/**
* nlmsvc_proc_cancel_msg - CANCEL_MSG: Cancel an outstanding lock request
* @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_CANCEL_MSG(nlm_cancargs) = 8;
*
* The response to this request is delivered via the CANCEL_RES procedure.
*/
static __be32 nlmsvc_proc_cancel_msg(struct svc_rqst *rqstp)
{
struct lockd_args *argp = rqstp->rq_argp;
struct nlm_host *host;
struct nlm_cancargs_wrapper *argp = rqstp->rq_argp;
struct nlm_host *host;
dprintk("lockd: CANCEL_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_CANCEL_RES,
__nlmsvc_proc_cancel);
__nlmsvc_proc_cancel_msg);
}
static __be32 nlmsvc_proc_unlock_msg(struct svc_rqst *rqstp)
@ -1188,15 +1208,15 @@ static const struct svc_procedure nlmsvc_procedures[24] = {
.pc_xdrressize = XDR_void,
.pc_name = "LOCK_MSG",
},
[NLMPROC_CANCEL_MSG] = {
.pc_func = nlmsvc_proc_cancel_msg,
.pc_decode = nlmsvc_decode_cancargs,
.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 = "CANCEL_MSG",
[NLM_CANCEL_MSG] = {
.pc_func = nlmsvc_proc_cancel_msg,
.pc_decode = nlm_svc_decode_nlm_cancargs,
.pc_encode = nlm_svc_encode_void,
.pc_argsize = sizeof(struct nlm_cancargs_wrapper),
.pc_argzero = 0,
.pc_ressize = 0,
.pc_xdrressize = XDR_void,
.pc_name = "CANCEL_MSG",
},
[NLMPROC_UNLOCK_MSG] = {
.pc_func = nlmsvc_proc_unlock_msg,