svcproc.c

linux 内核源代码

/*
 * linux/fs/lockd/svcproc.c
 *
 * Lockd server procedures. We don't implement the NLM_*_RES 
 * procedures because we don't use the async procedures.
 *
 * Copyright (C) 1996, Olaf Kirch <[e-mail]>
 */

#include <linux/types.h>
#include <linux/time.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfsd/nfsd.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/share.h>
#include <linux/lockd/sm_inter.h>


#define NLMDBG_FACILITY		NLMDBG_CLIENT

#ifdef CONFIG_LOCKD_V4
static __be32
cast_to_nlm(__be32 status, u32 vers)
{
	/* Note: status is assumed to be in network byte order !!! */
	if (vers != 4){
		switch (status) {
		case nlm_granted:
		case nlm_lck_denied:
		case nlm_lck_denied_nolocks:
		case nlm_lck_blocked:
		case nlm_lck_denied_grace_period:
		case nlm_drop_reply:
			break;
		case nlm4_deadlock:
			status = nlm_lck_denied;
			break;
		default:
			status = nlm_lck_denied_nolocks;
		}
	}

	return (status);
}
#define	cast_status(status) (cast_to_nlm(status, rqstp->rq_vers))
#else
#define cast_status(status) (status)
#endif

/*
 * Obtain client and file from arguments
 */
static __be32
nlmsvc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
			struct nlm_host **hostp, struct nlm_file **filp)
{
	struct nlm_host		*host = NULL;
	struct nlm_file		*file = NULL;
	struct nlm_lock		*lock = &argp->lock;
	__be32			error = 0;

	/* nfsd callbacks must have been installed for this procedure */
	if (!nlmsvc_ops)
		return nlm_lck_denied_nolocks;

	/* Obtain host handle */
	if (!(host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len))
	 || (argp->monitor && nsm_monitor(host) < 0))
		goto no_locks;
	*hostp = host;

	/* Obtain file pointer. Not used by FREE_ALL call. */
	if (filp != NULL) {
		if ((error = nlm_lookup_file(rqstp, &file, &lock->fh)) != 0)
			goto no_locks;
		*filp = file;

		/* Set up the missing parts of the file_lock structure */
		lock->fl.fl_file  = file->f_file;
		lock->fl.fl_owner = (fl_owner_t) host;
		lock->fl.fl_lmops = &nlmsvc_lock_operations;
	}

	return 0;

no_locks:
	if (host)
		nlm_release_host(host);
	if (error)
		return error;
	return nlm_lck_denied_nolocks;
}

/*
 * NULL: Test for presence of service
 */
static __be32
nlmsvc_proc_null(struct svc_rqst *rqstp, void *argp, void *resp)
{
	dprintk("lockd: NULL          called\n");
	return rpc_success;
}

/*
 * TEST: Check for conflicting lock
 */
static __be32
nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_args *argp,
				         struct nlm_res  *resp)
{
	struct nlm_host	*host;
	struct nlm_file	*file;

	dprintk("lockd: TEST          called\n");
	resp->cookie = argp->cookie;

	/* Don't accept test requests during grace period */
	if (nlmsvc_grace_period) {
		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_drop_reply ? rpc_drop_reply :rpc_success;

	/* Now check for conflicting locks */
	resp->status = cast_status(nlmsvc_testlock(rqstp, file, &argp->lock, &resp->lock, &resp->cookie));
	if (resp->status == nlm_drop_reply)
		return rpc_drop_reply;

	dprintk("lockd: TEST          status %d vers %d\n",
		ntohl(resp->status), rqstp->rq_vers);
	nlm_release_host(host);
	nlm_release_file(file);
	return rpc_success;
}

static __be32
nlmsvc_proc_lock(struct svc_rqst *rqstp, struct nlm_args *argp,
				         struct nlm_res  *resp)
{
	struct nlm_host	*host;
	struct nlm_file	*file;

	dprintk("lockd: LOCK          called\n");

	resp->cookie = argp->cookie;

	/* Don't accept new lock requests during grace period */
	if (nlmsvc_grace_period && !argp->reclaim) {
		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_drop_reply ? rpc_drop_reply :rpc_success;

#if 0
	/* If supplied state doesn't match current state, we assume it's
	 * an old request that time-warped somehow. Any error return would
	 * do in this case because it's irrelevant anyway.
	 *
	 * NB: We don't retrieve the remote host's state yet.
	 */
	if (host->h_nsmstate && host->h_nsmstate != argp->state) {
		resp->status = nlm_lck_denied_nolocks;
	} else
#endif

	/* Now try to lock the file */
	resp->status = cast_status(nlmsvc_lock(rqstp, file, &argp->lock,
					       argp->block, &argp->cookie));
	if (resp->status == nlm_drop_reply)
		return rpc_drop_reply;

	dprintk("lockd: LOCK          status %d\n", ntohl(resp->status));
	nlm_release_host(host);
	nlm_release_file(file);
	return rpc_success;
}

static __be32
nlmsvc_proc_cancel(struct svc_rqst *rqstp, struct nlm_args *argp,
				           struct nlm_res  *resp)
{
	struct nlm_host	*host;
	struct nlm_file	*file;

	dprintk("lockd: CANCEL        called\n");

	resp->cookie = argp->cookie;

	/* Don't accept requests during grace period */
	if (nlmsvc_grace_period) {
		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_drop_reply ? rpc_drop_reply :rpc_success;

	/* Try to cancel request. */
	resp->status = cast_status(nlmsvc_cancel_blocked(file, &argp->lock));

	dprintk("lockd: CANCEL        status %d\n", ntohl(resp->status));
	nlm_release_host(host);
	nlm_release_file(file);
	return rpc_success;
}

/*
 * UNLOCK: release a lock
 */
static __be32
nlmsvc_proc_unlock(struct svc_rqst *rqstp, struct nlm_args *argp,
				           struct nlm_res  *resp)
{
	struct nlm_host	*host;
	struct nlm_file	*file;

	dprintk("lockd: UNLOCK        called\n");

	resp->cookie = argp->cookie;

	/* Don't accept new lock requests during grace period */
	if (nlmsvc_grace_period) {
		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_drop_reply ? rpc_drop_reply :rpc_success;

	/* Now try to remove the lock */
	resp->status = cast_status(nlmsvc_unlock(file, &argp->lock));

	dprintk("lockd: UNLOCK        status %d\n", ntohl(resp->status));
	nlm_release_host(host);
	nlm_release_file(file);
	return 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 nlm_args *argp,
				            struct nlm_res  *resp)
{
	resp->cookie = argp->cookie;

	dprintk("lockd: GRANTED       called\n");
	resp->status = nlmclnt_grant(svc_addr_in(rqstp), &argp->lock);
	dprintk("lockd: GRANTED       status %d\n", ntohl(resp->status));
	return rpc_success;
}

/*
 * This is the generic lockd callback for async RPC calls
 */
static void nlmsvc_callback_exit(struct rpc_task *task, void *data)
{
	dprintk("lockd: %5u callback returned %d\n", task->tk_pid,
			-task->tk_status);
}

static void nlmsvc_callback_release(void *data)
{
	nlm_release_call(data);
}

static const struct rpc_call_ops nlmsvc_callback_ops = {
	.rpc_call_done = nlmsvc_callback_exit,