LockD: move global usage counter manipulation from error path

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / lockd / svc.c

/*
 * linux/fs/lockd/svc.c
 *
 * This is the central lockd service.
 *
 * FIXME: Separate the lockd NFS server functionality from the lockd NFS
 *        client functionality. Oh why didn't Sun create two separate
 *        services in the first place?
 *
 * Authors:     Olaf Kirch (okir@monad.swb.de)
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/moduleparam.h>

#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/uio.h>
#include <linux/smp.h>
#include <linux/mutex.h>
#include <linux/kthread.h>
#include <linux/freezer.h>

#include <linux/sunrpc/types.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <net/ip.h>
#include <linux/lockd/lockd.h>
#include <linux/nfs.h>

#include "netns.h"

#define NLMDBG_FACILITY         NLMDBG_SVC
#define LOCKD_BUFSIZE           (1024 + NLMSVC_XDRSIZE)
#define ALLOWED_SIGS            (sigmask(SIGKILL))

static struct svc_program       nlmsvc_program;

struct nlmsvc_binding *         nlmsvc_ops;
EXPORT_SYMBOL_GPL(nlmsvc_ops);

static DEFINE_MUTEX(nlmsvc_mutex);
static unsigned int             nlmsvc_users;
static struct task_struct       *nlmsvc_task;
static struct svc_rqst          *nlmsvc_rqst;
unsigned long                   nlmsvc_timeout;

int lockd_net_id;

/*
 * These can be set at insmod time (useful for NFS as root filesystem),
 * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
 */
static unsigned long            nlm_grace_period;
static unsigned long            nlm_timeout = LOCKD_DFLT_TIMEO;
static int                      nlm_udpport, nlm_tcpport;

/* RLIM_NOFILE defaults to 1024. That seems like a reasonable default here. */
static unsigned int             nlm_max_connections = 1024;

/*
 * Constants needed for the sysctl interface.
 */
static const unsigned long      nlm_grace_period_min = 0;
static const unsigned long      nlm_grace_period_max = 240;
static const unsigned long      nlm_timeout_min = 3;
static const unsigned long      nlm_timeout_max = 20;
static const int                nlm_port_min = 0, nlm_port_max = 65535;

#ifdef CONFIG_SYSCTL
static struct ctl_table_header * nlm_sysctl_table;
#endif

static unsigned long get_lockd_grace_period(void)
{
        /* Note: nlm_timeout should always be nonzero */
        if (nlm_grace_period)
                return roundup(nlm_grace_period, nlm_timeout) * HZ;
        else
                return nlm_timeout * 5 * HZ;
}

static struct lock_manager lockd_manager = {
};

static void grace_ender(struct work_struct *not_used)
{
        locks_end_grace(&lockd_manager);
}

static DECLARE_DELAYED_WORK(grace_period_end, grace_ender);

static void set_grace_period(void)
{
        unsigned long grace_period = get_lockd_grace_period();

        locks_start_grace(&lockd_manager);
        cancel_delayed_work_sync(&grace_period_end);
        schedule_delayed_work(&grace_period_end, grace_period);
}

static void restart_grace(void)
{
        if (nlmsvc_ops) {
                cancel_delayed_work_sync(&grace_period_end);
                locks_end_grace(&lockd_manager);
                nlmsvc_invalidate_all();
                set_grace_period();
        }
}

/*
 * This is the lockd kernel thread
 */
static int
lockd(void *vrqstp)
{
        int             err = 0, preverr = 0;
        struct svc_rqst *rqstp = vrqstp;

        /* try_to_freeze() is called from svc_recv() */
        set_freezable();

        /* Allow SIGKILL to tell lockd to drop all of its locks */
        allow_signal(SIGKILL);

        dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");

        if (!nlm_timeout)
                nlm_timeout = LOCKD_DFLT_TIMEO;
        nlmsvc_timeout = nlm_timeout * HZ;

        set_grace_period();

        /*
         * The main request loop. We don't terminate until the last
         * NFS mount or NFS daemon has gone away.
         */
        while (!kthread_should_stop()) {
                long timeout = MAX_SCHEDULE_TIMEOUT;
                RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);

                /* update sv_maxconn if it has changed */
                rqstp->rq_server->sv_maxconn = nlm_max_connections;

                if (signalled()) {
                        flush_signals(current);
                        restart_grace();
                        continue;
                }

                timeout = nlmsvc_retry_blocked();

                /*
                 * Find a socket with data available and call its
                 * recvfrom routine.
                 */
                err = svc_recv(rqstp, timeout);
                if (err == -EAGAIN || err == -EINTR) {
                        preverr = err;
                        continue;
                }
                if (err < 0) {
                        if (err != preverr) {
                                printk(KERN_WARNING "%s: unexpected error "
                                        "from svc_recv (%d)\n", __func__, err);
                                preverr = err;
                        }
                        schedule_timeout_interruptible(HZ);
                        continue;
                }
                preverr = err;

                dprintk("lockd: request from %s\n",
                                svc_print_addr(rqstp, buf, sizeof(buf)));

                svc_process(rqstp);
        }
        flush_signals(current);
        cancel_delayed_work_sync(&grace_period_end);
        locks_end_grace(&lockd_manager);
        if (nlmsvc_ops)
                nlmsvc_invalidate_all();
        nlm_shutdown_hosts();
        return 0;
}

static int create_lockd_listener(struct svc_serv *serv, const char *name,
                                 struct net *net, const int family,
                                 const unsigned short port)
{
        struct svc_xprt *xprt;

        xprt = svc_find_xprt(serv, name, net, family, 0);
        if (xprt == NULL)
                return svc_create_xprt(serv, name, net, family, port,
                                                SVC_SOCK_DEFAULTS);
        svc_xprt_put(xprt);
        return 0;
}

static int create_lockd_family(struct svc_serv *serv, struct net *net,
                               const int family)
{
        int err;

        err = create_lockd_listener(serv, "udp", net, family, nlm_udpport);
        if (err < 0)
                return err;

        return create_lockd_listener(serv, "tcp", net, family, nlm_tcpport);
}

/*
 * Ensure there are active UDP and TCP listeners for lockd.
 *
 * Even if we have only TCP NFS mounts and/or TCP NFSDs, some
 * local services (such as rpc.statd) still require UDP, and
 * some NFS servers do not yet support NLM over TCP.
 *
 * Returns zero if all listeners are available; otherwise a
 * negative errno value is returned.
 */
static int make_socks(struct svc_serv *serv, struct net *net)
{
        static int warned;
        int err;

        err = create_lockd_family(serv, net, PF_INET);
        if (err < 0)
                goto out_err;

        err = create_lockd_family(serv, net, PF_INET6);
        if (err < 0 && err != -EAFNOSUPPORT)
                goto out_err;

        warned = 0;
        return 0;

out_err:
        if (warned++ == 0)
                printk(KERN_WARNING
                        "lockd_up: makesock failed, error=%d\n", err);
        return err;
}

static int lockd_up_net(struct svc_serv *serv, struct net *net)
{
        struct lockd_net *ln = net_generic(net, lockd_net_id);
        int error;

        if (ln->nlmsvc_users++)
                return 0;

        error = svc_bind(serv, net);
        if (error)
                goto err_bind;

        error = make_socks(serv, net);
        if (error < 0)
                goto err_socks;
        return 0;

err_socks:
        svc_rpcb_cleanup(serv, net);
err_bind:
        ln->nlmsvc_users--;
        return error;
}

static void lockd_down_net(struct svc_serv *serv, struct net *net)
{
        struct lockd_net *ln = net_generic(net, lockd_net_id);

        if (ln->nlmsvc_users) {
                if (--ln->nlmsvc_users == 0) {
                        nlm_shutdown_hosts_net(net);
                        svc_shutdown_net(serv, net);
                }
        } else {
                printk(KERN_ERR "lockd_down_net: no users! task=%p, net=%p\n",
                                nlmsvc_task, net);
                BUG();
        }
}

static struct svc_serv *lockd_create_svc(void)
{
        struct svc_serv *serv;

        /*
         * Check whether we're already up and running.
         */
        if (nlmsvc_rqst) {
                /*
                 * Note: increase service usage, because later in case of error
                 * svc_destroy() will be called.
                 */
                svc_get(nlmsvc_rqst->rq_server);
                return nlmsvc_rqst->rq_server;
        }

        /*
         * Sanity check: if there's no pid,
         * we should be the first user ...
         */
        if (nlmsvc_users)
                printk(KERN_WARNING
                        "lockd_up: no pid, %d users??\n", nlmsvc_users);

        serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
        if (!serv) {
                printk(KERN_WARNING "lockd_up: create service failed\n");
                return ERR_PTR(-ENOMEM);
        }
        return serv;
}

/*
 * Bring up the lockd process if it's not already up.
 */
int lockd_up(struct net *net)
{
        struct svc_serv *serv;
        int error;

        mutex_lock(&nlmsvc_mutex);

        serv = lockd_create_svc();
        if (IS_ERR(serv)) {
                error = PTR_ERR(serv);
                goto err_create;
        }

        error = lockd_up_net(serv, net);
        if (error < 0)
                goto err_net;

        /*
         * Create the kernel thread and wait for it to start.
         */
        nlmsvc_rqst = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
        if (IS_ERR(nlmsvc_rqst)) {
                error = PTR_ERR(nlmsvc_rqst);
                nlmsvc_rqst = NULL;
                printk(KERN_WARNING
                        "lockd_up: svc_rqst allocation failed, error=%d\n",
                        error);
                goto err_start;
        }

        svc_sock_update_bufs(serv);
        serv->sv_maxconn = nlm_max_connections;

        nlmsvc_task = kthread_run(lockd, nlmsvc_rqst, serv->sv_name);
        if (IS_ERR(nlmsvc_task)) {
                error = PTR_ERR(nlmsvc_task);
                svc_exit_thread(nlmsvc_rqst);
                nlmsvc_task = NULL;
                nlmsvc_rqst = NULL;
                printk(KERN_WARNING
                        "lockd_up: kthread_run failed, error=%d\n", error);
                goto err_start;
        }

        nlmsvc_users++;
        /*
         * Note: svc_serv structures have an initial use count of 1,
         * so we exit through here on both success and failure.
         */
err_net:
        svc_destroy(serv);
err_create:
        mutex_unlock(&nlmsvc_mutex);
        return error;

err_start:
        lockd_down_net(serv, net);
        goto err_net;
}
EXPORT_SYMBOL_GPL(lockd_up);

/*
 * Decrement the user count and bring down lockd if we're the last.
 */
void
lockd_down(struct net *net)
{
        mutex_lock(&nlmsvc_mutex);
        lockd_down_net(nlmsvc_rqst->rq_server, net);
        if (nlmsvc_users) {
                if (--nlmsvc_users)
                        goto out;
        } else {
                printk(KERN_ERR "lockd_down: no users! task=%p\n",
                        nlmsvc_task);
                BUG();
        }

        if (!nlmsvc_task) {
                printk(KERN_ERR "lockd_down: no lockd running.\n");
                BUG();
        }
        kthread_stop(nlmsvc_task);
        svc_exit_thread(nlmsvc_rqst);
        nlmsvc_task = NULL;
        nlmsvc_rqst = NULL;
out:
        mutex_unlock(&nlmsvc_mutex);
}
EXPORT_SYMBOL_GPL(lockd_down);

#ifdef CONFIG_SYSCTL

/*
 * Sysctl parameters (same as module parameters, different interface).
 */

static ctl_table nlm_sysctls[] = {
        {
                .procname       = "nlm_grace_period",
                .data           = &nlm_grace_period,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
                .extra1         = (unsigned long *) &nlm_grace_period_min,
                .extra2         = (unsigned long *) &nlm_grace_period_max,
        },
        {
                .procname       = "nlm_timeout",
                .data           = &nlm_timeout,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
                .extra1         = (unsigned long *) &nlm_timeout_min,
                .extra2         = (unsigned long *) &nlm_timeout_max,
        },
        {
                .procname       = "nlm_udpport",
                .data           = &nlm_udpport,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = (int *) &nlm_port_min,
                .extra2         = (int *) &nlm_port_max,
        },
        {
                .procname       = "nlm_tcpport",
                .data           = &nlm_tcpport,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = (int *) &nlm_port_min,
                .extra2         = (int *) &nlm_port_max,
        },
        {
                .procname       = "nsm_use_hostnames",
                .data           = &nsm_use_hostnames,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "nsm_local_state",
                .data           = &nsm_local_state,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        { }
};

static ctl_table nlm_sysctl_dir[] = {
        {
                .procname       = "nfs",
                .mode           = 0555,
                .child          = nlm_sysctls,
        },
        { }
};

static ctl_table nlm_sysctl_root[] = {
        {
                .procname       = "fs",
                .mode           = 0555,
                .child          = nlm_sysctl_dir,
        },
        { }
};

#endif  /* CONFIG_SYSCTL */

/*
 * Module (and sysfs) parameters.
 */

#define param_set_min_max(name, type, which_strtol, min, max)           \
static int param_set_##name(const char *val, struct kernel_param *kp)   \
{                                                                       \
        char *endp;                                                     \
        __typeof__(type) num = which_strtol(val, &endp, 0);             \
        if (endp == val || *endp || num < (min) || num > (max))         \
                return -EINVAL;                                         \
        *((type *) kp->arg) = num;                                      \
        return 0;                                                       \
}

static inline int is_callback(u32 proc)
{
        return proc == NLMPROC_GRANTED
                || proc == NLMPROC_GRANTED_MSG
                || proc == NLMPROC_TEST_RES
                || proc == NLMPROC_LOCK_RES
                || proc == NLMPROC_CANCEL_RES
                || proc == NLMPROC_UNLOCK_RES
                || proc == NLMPROC_NSM_NOTIFY;
}


static int lockd_authenticate(struct svc_rqst *rqstp)
{
        rqstp->rq_client = NULL;
        switch (rqstp->rq_authop->flavour) {
                case RPC_AUTH_NULL:
                case RPC_AUTH_UNIX:
                        if (rqstp->rq_proc == 0)
                                return SVC_OK;
                        if (is_callback(rqstp->rq_proc)) {
                                /* Leave it to individual procedures to
                                 * call nlmsvc_lookup_host(rqstp)
                                 */
                                return SVC_OK;
                        }
                        return svc_set_client(rqstp);
        }
        return SVC_DENIED;
}


param_set_min_max(port, int, simple_strtol, 0, 65535)
param_set_min_max(grace_period, unsigned long, simple_strtoul,
                  nlm_grace_period_min, nlm_grace_period_max)
param_set_min_max(timeout, unsigned long, simple_strtoul,
                  nlm_timeout_min, nlm_timeout_max)

MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
MODULE_LICENSE("GPL");

module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
                  &nlm_grace_period, 0644);
module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
                  &nlm_timeout, 0644);
module_param_call(nlm_udpport, param_set_port, param_get_int,
                  &nlm_udpport, 0644);
module_param_call(nlm_tcpport, param_set_port, param_get_int,
                  &nlm_tcpport, 0644);
module_param(nsm_use_hostnames, bool, 0644);
module_param(nlm_max_connections, uint, 0644);

static int lockd_init_net(struct net *net)
{
        return 0;
}

static void lockd_exit_net(struct net *net)
{
}

static struct pernet_operations lockd_net_ops = {
        .init = lockd_init_net,
        .exit = lockd_exit_net,
        .id = &lockd_net_id,
        .size = sizeof(struct lockd_net),
};


/*
 * Initialising and terminating the module.
 */

static int __init init_nlm(void)
{
        int err;

#ifdef CONFIG_SYSCTL
        err = -ENOMEM;
        nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
        if (nlm_sysctl_table == NULL)
                goto err_sysctl;
#endif
        err = register_pernet_subsys(&lockd_net_ops);
        if (err)
                goto err_pernet;
        return 0;

err_pernet:
#ifdef CONFIG_SYSCTL
        unregister_sysctl_table(nlm_sysctl_table);
#endif
err_sysctl:
        return err;
}

static void __exit exit_nlm(void)
{
        /* FIXME: delete all NLM clients */
        nlm_shutdown_hosts();
        unregister_pernet_subsys(&lockd_net_ops);
#ifdef CONFIG_SYSCTL
        unregister_sysctl_table(nlm_sysctl_table);
#endif
}

module_init(init_nlm);
module_exit(exit_nlm);

/*
 * Define NLM program and procedures
 */
static struct svc_version       nlmsvc_version1 = {
                .vs_vers        = 1,
                .vs_nproc       = 17,
                .vs_proc        = nlmsvc_procedures,
                .vs_xdrsize     = NLMSVC_XDRSIZE,
};
static struct svc_version       nlmsvc_version3 = {
                .vs_vers        = 3,
                .vs_nproc       = 24,
                .vs_proc        = nlmsvc_procedures,
                .vs_xdrsize     = NLMSVC_XDRSIZE,
};
#ifdef CONFIG_LOCKD_V4
static struct svc_version       nlmsvc_version4 = {
                .vs_vers        = 4,
                .vs_nproc       = 24,
                .vs_proc        = nlmsvc_procedures4,
                .vs_xdrsize     = NLMSVC_XDRSIZE,
};
#endif
static struct svc_version *     nlmsvc_version[] = {
        [1] = &nlmsvc_version1,
        [3] = &nlmsvc_version3,
#ifdef CONFIG_LOCKD_V4
        [4] = &nlmsvc_version4,
#endif
};

static struct svc_stat          nlmsvc_stats;

#define NLM_NRVERS      ARRAY_SIZE(nlmsvc_version)
static struct svc_program       nlmsvc_program = {
        .pg_prog                = NLM_PROGRAM,          /* program number */
        .pg_nvers               = NLM_NRVERS,           /* number of entries in nlmsvc_version */
        .pg_vers                = nlmsvc_version,       /* version table */
        .pg_name                = "lockd",              /* service name */
        .pg_class               = "nfsd",               /* share authentication with nfsd */
        .pg_stats               = &nlmsvc_stats,        /* stats table */
        .pg_authenticate = &lockd_authenticate  /* export authentication */
};