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/*

 * linux/fs/nfsd/nfssvc.c

 *

 * Central processing for nfsd.

 *

 * Authors:     Olaf Kirch (okir@monad.swb.de)

 *

 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>

 */

#define __NO_VERSION__

#include <linux/config.h>

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/errno.h>

#include <linux/nfs.h>

#include <linux/in.h>

#include <linux/uio.h>

#include <linux/version.h>

#include <linux/unistd.h>

#include <linux/slab.h>

#include <linux/smp.h>

#include <linux/smp_lock.h>

#include <linux/sunrpc/types.h>

#include <linux/sunrpc/stats.h>

#include <linux/sunrpc/svc.h>

#include <linux/sunrpc/svcsock.h>

#include <linux/nfsd/nfsd.h>

#include <linux/nfsd/stats.h>

#include <linux/nfsd/cache.h>

#include <linux/nfsd/xdr.h>

#include <linux/lockd/bind.h>

#define NFSDDBG_FACILITY        NFSDDBG_SVC

#define NFSD_BUFSIZE            (1024 + NFSSVC_MAXBLKSIZE)

/* these signals will be delivered to an nfsd thread

 * when handling a request

 */

#define ALLOWED_SIGS    (sigmask(SIGKILL))

/* these signals will be delivered to an nfsd thread

 * when not handling a request. i.e. when waiting

 */

#define SHUTDOWN_SIGS   (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT))

/* if the last thread dies with SIGHUP, then the exports table is

 * left unchanged ( like 2.4-{0-9} ).  Any other signal will clear

 * the exports table (like 2.2).

 */

#define SIG_NOCLEAN     SIGHUP

extern struct svc_program       nfsd_program;

static void                     nfsd(struct svc_rqst *rqstp);

struct timeval                  nfssvc_boot;

static struct svc_serv          *nfsd_serv;

static int                      nfsd_busy;

static unsigned long            nfsd_last_call;

struct nfsd_list {

        struct list_head        list;

        struct task_struct      *task;

};

struct list_head nfsd_list = LIST_HEAD_INIT(nfsd_list);

/*

 * Maximum number of nfsd processes

 */

#define NFSD_MAXSERVS           8192

int

nfsd_svc(unsigned short port, int nrservs)

{

        int     error;

        int     none_left;

        struct list_head *victim;

        dprintk("nfsd: creating service\n");

        error = -EINVAL;

        if (nrservs <= 0)

                nrservs = 0;

        if (nrservs > NFSD_MAXSERVS)

                nrservs = NFSD_MAXSERVS;

        /* Readahead param cache - will no-op if it already exists */

        error = nfsd_racache_init(2*nrservs);

        if (error<0)

                goto out;

        if (!nfsd_serv) {

                error = -ENOMEM;

                nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE, NFSSVC_XDRSIZE);

                if (nfsd_serv == NULL)

                        goto out;

                error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);

                if (error < 0)

                        goto failure;

#if CONFIG_NFSD_TCP

                error = svc_makesock(nfsd_serv, IPPROTO_TCP, port);

                if (error < 0)

                        goto failure;

#endif

                do_gettimeofday(&nfssvc_boot);          /* record boot time */

        } else

                nfsd_serv->sv_nrthreads++;

        nrservs -= (nfsd_serv->sv_nrthreads-1);

        while (nrservs > 0) {

                nrservs--;

                error = svc_create_thread(nfsd, nfsd_serv);

                if (error < 0)

                        break;

        }

        victim = nfsd_list.next;

        while (nrservs < 0 && victim != &nfsd_list) {

                struct nfsd_list *nl =

                        list_entry(victim,struct nfsd_list, list);

                victim = victim->next;

                send_sig(SIG_NOCLEAN, nl->task, 1);

                nrservs++;

        }

 failure:

        none_left = (nfsd_serv->sv_nrthreads == 1);

        svc_destroy(nfsd_serv);         /* Release server */

        if (none_left) {

                nfsd_serv = NULL;

                nfsd_racache_shutdown();

        }

 out:

        return error;

}

static inline void

update_thread_usage(int busy_threads)

{

        unsigned long prev_call;

        unsigned long diff;

        int decile;

        prev_call = nfsd_last_call;

        nfsd_last_call = jiffies;

        decile = busy_threads*10/nfsdstats.th_cnt;

        if (decile>0 && decile <= 10) {

                diff = nfsd_last_call - prev_call;

                if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)

                        nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;

                if (decile == 10)

                        nfsdstats.th_fullcnt++;

        }

}

/*

 * This is the NFS server kernel thread

 */

static void

nfsd(struct svc_rqst *rqstp)

{

        struct svc_serv *serv = rqstp->rq_server;

        int             err;

        struct nfsd_list me;

        /* Lock module and set up kernel thread */

        MOD_INC_USE_COUNT;

        lock_kernel();

        daemonize();

        sprintf(current->comm, "nfsd");

        current->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;

        nfsdstats.th_cnt++;

        /* Let svc_process check client's authentication. */

        rqstp->rq_auth = 1;

        lockd_up();                             /* start lockd */

        me.task = current;

        list_add(&me.list, &nfsd_list);

        /*

         * The main request loop

         */

        for (;;) {

                /* Block all but the shutdown signals */

                spin_lock_irq(&current->sigmask_lock);

                siginitsetinv(&current->blocked, SHUTDOWN_SIGS);

                recalc_sigpending(current);

                spin_unlock_irq(&current->sigmask_lock);

                /*

                 * Find a socket with data available and call its

                 * recvfrom routine.

                 */

                while ((err = svc_recv(serv, rqstp,

                                       5*60*HZ)) == -EAGAIN)

                    ;

                if (err < 0)

                        break;

                update_thread_usage(nfsd_busy);

                nfsd_busy++;

                /* Lock the export hash tables for reading. */

                exp_readlock();

                /* Validate the client's address. This will also defeat

                 * port probes on port 2049 by unauthorized clients.

                 */

                rqstp->rq_client = exp_getclient(&rqstp->rq_addr);

                /* Process request with signals blocked.  */

                spin_lock_irq(&current->sigmask_lock);

                siginitsetinv(&current->blocked, ALLOWED_SIGS);

                recalc_sigpending(current);

                spin_unlock_irq(&current->sigmask_lock);

                svc_process(serv, rqstp);

                /* Unlock export hash tables */

                exp_unlock();

                update_thread_usage(nfsd_busy);

                nfsd_busy--;

        }

        if (err != -EINTR) {

                printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);

        } else {

                unsigned int    signo;

                for (signo = 1; signo <= _NSIG; signo++)

                        if (sigismember(&current->pending.signal, signo) &&

                            !sigismember(&current->blocked, signo))

                                break;

                err = signo;

        }

        /* Release lockd */

        lockd_down();

        /* Check if this is last thread */

        if (serv->sv_nrthreads==1) {

                printk(KERN_WARNING "nfsd: last server has exited\n");

                if (err != SIG_NOCLEAN) {

                        printk(KERN_WARNING "nfsd: unexporting all filesystems\n");

                        nfsd_export_shutdown();

                }

                nfsd_serv = NULL;

                nfsd_racache_shutdown();        /* release read-ahead cache */

        }

        list_del(&me.list);

        nfsdstats.th_cnt --;

        /* Release the thread */

        svc_exit_thread(rqstp);

        /* Release module */

        MOD_DEC_USE_COUNT;

}

static int

nfsd_dispatch(struct svc_rqst *rqstp, u32 *statp)

{

        struct svc_procedure    *proc;

        kxdrproc_t              xdr;

        u32                     nfserr;

        dprintk("nfsd_dispatch: vers %d proc %d\n",

                                rqstp->rq_vers, rqstp->rq_proc);

        proc = rqstp->rq_procinfo;

        /* Check whether we have this call in the cache. */

        switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) {

        case RC_INTR:

        case RC_DROPIT:

                return 0;

        case RC_REPLY:

                return 1;

        case RC_DOIT:;

                /* do it */

        }

        /* Decode arguments */

        xdr = proc->pc_decode;

        if (xdr && !xdr(rqstp, rqstp->rq_argbuf.buf, rqstp->rq_argp)) {

                dprintk("nfsd: failed to decode arguments!\n");

                nfsd_cache_update(rqstp, RC_NOCACHE, NULL);

                *statp = rpc_garbage_args;

                return 1;

        }

        /* Now call the procedure handler, and encode NFS status. */

        nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);

        if (nfserr == nfserr_dropit) {

                dprintk("nfsd: Dropping request due to malloc failure!\n");

                nfsd_cache_update(rqstp, RC_NOCACHE, NULL);

                return 0;

        }

        if (rqstp->rq_proc != 0)

                svc_putlong(&rqstp->rq_resbuf, nfserr);

        /* Encode result.

         * For NFSv2, additional info is never returned in case of an error.

         */

        if (!(nfserr && rqstp->rq_vers == 2)) {

                xdr = proc->pc_encode;

                if (xdr && !xdr(rqstp, rqstp->rq_resbuf.buf, rqstp->rq_resp)) {

                        /* Failed to encode result. Release cache entry */

                        dprintk("nfsd: failed to encode result!\n");

                        nfsd_cache_update(rqstp, RC_NOCACHE, NULL);

                        *statp = rpc_system_err;

                        return 1;

                }

        }

        /* Store reply in cache. */

        nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);

        return 1;

}

static struct svc_version       nfsd_version2 = {

        2, 18, nfsd_procedures2, nfsd_dispatch

};

#ifdef CONFIG_NFSD_V3

static struct svc_version       nfsd_version3 = {

        3, 22, nfsd_procedures3, nfsd_dispatch

};

#endif

static struct svc_version *     nfsd_version[] = {

        NULL,

        NULL,

        &nfsd_version2,

#ifdef CONFIG_NFSD_V3

        &nfsd_version3,

#endif

};

#define NFSD_NRVERS             (sizeof(nfsd_version)/sizeof(nfsd_version[0]))

struct svc_program              nfsd_program = {

        NFS_PROGRAM,            /* program number */

        2, NFSD_NRVERS-1,       /* version range */

        NFSD_NRVERS,            /* nr of entries in nfsd_version */

        nfsd_version,           /* version table */

        "nfsd",                 /* program name */

        &nfsd_svcstats,         /* version table */

};