/*
* LOCK: Try to create a lock
*
* Programmer Harassment Alert
*
* When given a blocking lock request in a sync RPC call, the HPUX lockd
* will faithfully return LCK_BLOCKED but never cares to notify us when
* the lock could be granted. This way, our local process could hang
* around forever waiting for the callback.
*
* Solution A: Implement busy-waiting
* Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
*
* For now I am implementing solution A, because I hate the idea of
* re-implementing lockd for a third time in two months. The async
* calls shouldn't be too hard to do, however.
*
* This is one of the lovely things about standards in the NFS area:
* they're so soft and squishy you can't really blame HP for doing this.
*/
static int
nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
{
struct nlm_host *host = req->a_host;
struct nlm_res *resp = &req->a_res;
int status;
if (!host->h_monitored && nsm_monitor(host) < 0) {
printk(KERN_NOTICE "lockd: failed to monitor %s\n",
host->h_name);
return -ENOLCK;
}
while (1) {
if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0) {
if (resp->status != NLM_LCK_BLOCKED)
break;
status = nlmclnt_block(host, fl, &resp->status);
}
if (status < 0)
return status;
}
if (resp->status == NLM_LCK_GRANTED) {
fl->fl_u.nfs_fl.state = host->h_state;
fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
}
return nlm_stat_to_errno(resp->status);
}
/*
* TEST for the presence of a conflicting lock
*/
static int
nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
{
int status;
if ((status = nlmclnt_call(req, NLMPROC_TEST)) < 0)
return status;
status = req->a_res.status;
if (status == NLM_LCK_GRANTED) {
fl->fl_type = F_UNLCK;
} if (status == NLM_LCK_DENIED) {
/*
* Report the conflicting lock back to the application.
* FIXME: Is it OK to report the pid back as well?
*/
memcpy(fl, &req->a_res.lock.fl, sizeof(*fl));
/* fl->fl_pid = 0; */
} else {
return nlm_stat_to_errno(req->a_res.status);
}
return 0;
}
/*
* Generic NLM call, async version.
*/
int
nlmsvc_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
{
struct nlm_host *host = req->a_host;
struct rpc_clnt *clnt;
struct rpc_message msg = {
.rpc_argp = &req->a_args,
.rpc_resp = &req->a_res,
};
int status;
dprintk("lockd: call procedure %d on %s (async)\n",
(int)proc, host->h_name);
/* If we have no RPC client yet, create one. */
if ((clnt = nlm_bind_host(host)) == NULL)
return -ENOLCK;
msg.rpc_proc = &clnt->cl_procinfo[proc];
/* bootstrap and kick off the async RPC call */
status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
return status;
}
int
nlmclnt_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
{
struct nlm_host *host = req->a_host;
struct rpc_clnt *clnt;
struct nlm_args *argp = &req->a_args;
struct nlm_res *resp = &req->a_res;
struct file *file = argp->lock.fl.fl_file;
struct rpc_message msg = {
.rpc_argp = argp,
.rpc_resp = resp,
};
int status;
dprintk("lockd: call procedure %d on %s (async)\n",
(int)proc, host->h_name);
/* If we have no RPC client yet, create one. */
if ((clnt = nlm_bind_host(host)) == NULL)
return -ENOLCK;
msg.rpc_proc = &clnt->cl_procinfo[proc];
/* bootstrap and kick off the async RPC call */
if (file)
msg.rpc_cred = nfs_file_cred(file);
/* Increment host refcount */
nlm_get_host(host);
status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
if (status < 0)
nlm_release_host(host);
return status;
}
/*
* TEST for the presence of a conflicting lock
*/
static int
nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
{
int status;
if ((status = nlmclnt_call(req, NLMPROC_TEST)) < 0)
return status;
status = req->a_res.status;
if (status == NLM_LCK_GRANTED) {
fl->fl_type = F_UNLCK;
} if (status == NLM_LCK_DENIED) {
/*
* Report the conflicting lock back to the application.
* FIXME: Is it OK to report the pid back as well?
*/
locks_copy_lock(fl, &req->a_res.lock.fl);
/* fl->fl_pid = 0; */
} else {
return nlm_stat_to_errno(req->a_res.status);
}
return 0;
}
