// SPDX-License-Identifier: GPL-2.0-only
/*
 * Syscall interface to knfsd.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/ctype.h>
#include <linux/fs_context.h>

#include <linux/sunrpc/svcsock.h>
#include <linux/lockd/lockd.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/gss_api.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <linux/sunrpc/svc.h>
#include <linux/module.h>
#include <linux/fsnotify.h>
#include <linux/nfslocalio.h>

#include "idmap.h"
#include "nfsd.h"
#include "cache.h"
#include "state.h"
#include "netns.h"
#include "pnfs.h"
#include "filecache.h"
#include "trace.h"
#include "netlink.h"

/*
 *      We have a single directory with several nodes in it.
 */
enum {
        NFSD_Root = 1,
        NFSD_List,
        NFSD_Export_Stats,
        NFSD_Export_features,
        NFSD_Fh,
        NFSD_FO_UnlockIP,
        NFSD_FO_UnlockFS,
        NFSD_Threads,
        NFSD_Pool_Threads,
        NFSD_Pool_Stats,
        NFSD_Reply_Cache_Stats,
        NFSD_Versions,
        NFSD_Ports,
        NFSD_MaxBlkSize,
        NFSD_Filecache,
        NFSD_Leasetime,
        NFSD_Gracetime,
        NFSD_RecoveryDir,
        NFSD_V4EndGrace,
        NFSD_MaxReserved
};

/*
 * write() for these nodes.
 */
static ssize_t write_filehandle(struct file *file, char *buf, size_t size);
static ssize_t write_unlock_ip(struct file *file, char *buf, size_t size);
static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size);
static ssize_t write_threads(struct file *file, char *buf, size_t size);
static ssize_t write_pool_threads(struct file *file, char *buf, size_t size);
static ssize_t write_versions(struct file *file, char *buf, size_t size);
static ssize_t write_ports(struct file *file, char *buf, size_t size);
static ssize_t write_maxblksize(struct file *file, char *buf, size_t size);
#ifdef CONFIG_NFSD_V4
static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
static ssize_t write_gracetime(struct file *file, char *buf, size_t size);
#ifdef CONFIG_NFSD_LEGACY_CLIENT_TRACKING
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
#endif
static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size);
#endif

static ssize_t (*const write_op[])(struct file *, char *, size_t) = {
        [NFSD_Fh] = write_filehandle,
        [NFSD_FO_UnlockIP] = write_unlock_ip,
        [NFSD_FO_UnlockFS] = write_unlock_fs,
        [NFSD_Threads] = write_threads,
        [NFSD_Pool_Threads] = write_pool_threads,
        [NFSD_Versions] = write_versions,
        [NFSD_Ports] = write_ports,
        [NFSD_MaxBlkSize] = write_maxblksize,
#ifdef CONFIG_NFSD_V4
        [NFSD_Leasetime] = write_leasetime,
        [NFSD_Gracetime] = write_gracetime,
#ifdef CONFIG_NFSD_LEGACY_CLIENT_TRACKING
        [NFSD_RecoveryDir] = write_recoverydir,
#endif
        [NFSD_V4EndGrace] = write_v4_end_grace,
#endif
};

static ssize_t nfsctl_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
{
        ino_t ino =  file_inode(file)->i_ino;
        char *data;
        ssize_t rv;

        if (ino >= ARRAY_SIZE(write_op) || !write_op[ino])
                return -EINVAL;

        data = simple_transaction_get(file, buf, size);
        if (IS_ERR(data))
                return PTR_ERR(data);

        rv = write_op[ino](file, data, size);
        if (rv < 0)
                return rv;

        simple_transaction_set(file, rv);
        return size;
}

static ssize_t nfsctl_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
{
        if (! file->private_data) {
                /* An attempt to read a transaction file without writing
                 * causes a 0-byte write so that the file can return
                 * state information
                 */
                ssize_t rv = nfsctl_transaction_write(file, buf, 0, pos);
                if (rv < 0)
                        return rv;
        }
        return simple_transaction_read(file, buf, size, pos);
}

static const struct file_operations transaction_ops = {
        .write          = nfsctl_transaction_write,
        .read           = nfsctl_transaction_read,
        .release        = simple_transaction_release,
        .llseek         = default_llseek,
};

static int exports_net_open(struct net *net, struct file *file)
{
        int err;
        struct seq_file *seq;
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);

        err = seq_open(file, &nfs_exports_op);
        if (err)
                return err;

        seq = file->private_data;
        seq->private = nn->svc_export_cache;
        get_net(net);
        return 0;
}

static int exports_release(struct inode *inode, struct file *file)
{
        struct seq_file *seq = file->private_data;
        struct cache_detail *cd = seq->private;

        put_net(cd->net);
        return seq_release(inode, file);
}

static int exports_nfsd_open(struct inode *inode, struct file *file)
{
        return exports_net_open(inode->i_sb->s_fs_info, file);
}

static const struct file_operations exports_nfsd_operations = {
        .open           = exports_nfsd_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = exports_release,
};

static int export_features_show(struct seq_file *m, void *v)
{
        seq_printf(m, "0x%x 0x%x\n", NFSEXP_ALLFLAGS, NFSEXP_SECINFO_FLAGS);
        return 0;
}

DEFINE_SHOW_ATTRIBUTE(export_features);

static int nfsd_pool_stats_open(struct inode *inode, struct file *file)
{
        struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id);

        return svc_pool_stats_open(&nn->nfsd_info, file);
}

static const struct file_operations pool_stats_operations = {
        .open           = nfsd_pool_stats_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

DEFINE_SHOW_ATTRIBUTE(nfsd_reply_cache_stats);

DEFINE_SHOW_ATTRIBUTE(nfsd_file_cache_stats);

/*----------------------------------------------------------------------------*/
/*
 * payload - write methods
 */

static inline struct net *netns(struct file *file)
{
        return file_inode(file)->i_sb->s_fs_info;
}

/*
 * write_unlock_ip - Release all locks used by a client
 *
 * Experimental.
 *
 * Input:
 *                      buf:    '\n'-terminated C string containing a
 *                              presentation format IP address
 *                      size:   length of C string in @buf
 * Output:
 *      On success:     returns zero if all specified locks were released;
 *                      returns one if one or more locks were not released
 *      On error:       return code is negative errno value
 */
static ssize_t write_unlock_ip(struct file *file, char *buf, size_t size)
{
        struct sockaddr_storage address;
        struct sockaddr *sap = (struct sockaddr *)&address;
        size_t salen = sizeof(address);
        char *fo_path;
        struct net *net = netns(file);

        /* sanity check */
        if (size == 0)
                return -EINVAL;

        if (buf[size-1] != '\n')
                return -EINVAL;

        fo_path = buf;
        if (qword_get(&buf, fo_path, size) < 0)
                return -EINVAL;

        if (rpc_pton(net, fo_path, size, sap, salen) == 0)
                return -EINVAL;

        trace_nfsd_ctl_unlock_ip(net, buf);
        return nlmsvc_unlock_all_by_ip(sap);
}

/*
 * write_unlock_fs - Release all locks on a local file system
 *
 * Experimental.
 *
 * Input:
 *                      buf:    '\n'-terminated C string containing the
 *                              absolute pathname of a local file system
 *                      size:   length of C string in @buf
 * Output:
 *      On success:     returns zero if all specified locks were released;
 *                      returns one if one or more locks were not released
 *      On error:       return code is negative errno value
 */
static ssize_t write_unlock_fs(struct file *file, char *buf, size_t size)
{
        struct path path;
        char *fo_path;
        int error;
        struct nfsd_net *nn;

        /* sanity check */
        if (size == 0)
                return -EINVAL;

        if (buf[size-1] != '\n')
                return -EINVAL;

        fo_path = buf;
        if (qword_get(&buf, fo_path, size) < 0)
                return -EINVAL;
        trace_nfsd_ctl_unlock_fs(netns(file), fo_path);
        error = kern_path(fo_path, 0, &path);
        if (error)
                return error;

        /*
         * XXX: Needs better sanity checking.  Otherwise we could end up
         * releasing locks on the wrong file system.
         *
         * For example:
         * 1.  Does the path refer to a directory?
         * 2.  Is that directory a mount point, or
         * 3.  Is that directory the root of an exported file system?
         */
        nfsd4_cancel_copy_by_sb(netns(file), path.dentry->d_sb);
        error = nlmsvc_unlock_all_by_sb(path.dentry->d_sb);
        mutex_lock(&nfsd_mutex);
        nn = net_generic(netns(file), nfsd_net_id);
        if (nn->nfsd_serv)
                nfsd4_revoke_states(nn, path.dentry->d_sb);
        else
                error = -EINVAL;
        mutex_unlock(&nfsd_mutex);

        path_put(&path);
        return error;
}

/*
 * write_filehandle - Get a variable-length NFS file handle by path
 *
 * On input, the buffer contains a '\n'-terminated C string comprised of
 * three alphanumeric words separated by whitespace.  The string may
 * contain escape sequences.
 *
 * Input:
 *                      buf:
 *                              domain:         client domain name
 *                              path:           export pathname
 *                              maxsize:        numeric maximum size of
 *                                              @buf
 *                      size:   length of C string in @buf
 * Output:
 *      On success:     passed-in buffer filled with '\n'-terminated C
 *                      string containing a ASCII hex text version
 *                      of the NFS file handle;
 *                      return code is the size in bytes of the string
 *      On error:       return code is negative errno value
 */
static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
{
        char *dname, *path;
        int maxsize;
        char *mesg = buf;
        int len;
        struct auth_domain *dom;
        struct knfsd_fh fh;

        if (size == 0)
                return -EINVAL;

        if (buf[size-1] != '\n')
                return -EINVAL;
        buf[size-1] = 0;

        dname = mesg;
        len = qword_get(&mesg, dname, size);
        if (len <= 0)
                return -EINVAL;

        path = dname+len+1;
        len = qword_get(&mesg, path, size);
        if (len <= 0)
                return -EINVAL;

        len = get_int(&mesg, &maxsize);
        if (len)
                return len;

        if (maxsize < NFS_FHSIZE)
                return -EINVAL;
        maxsize = min(maxsize, NFS3_FHSIZE);

        if (qword_get(&mesg, mesg, size) > 0)
                return -EINVAL;

        trace_nfsd_ctl_filehandle(netns(file), dname, path, maxsize);

        /* we have all the words, they are in buf.. */
        dom = unix_domain_find(dname);
        if (!dom)
                return -ENOMEM;

        len = exp_rootfh(netns(file), dom, path, &fh, maxsize);
        auth_domain_put(dom);
        if (len)
                return len;

        mesg = buf;
        len = SIMPLE_TRANSACTION_LIMIT;
        qword_addhex(&mesg, &len, fh.fh_raw, fh.fh_size);
        mesg[-1] = '\n';
        return mesg - buf;
}

/*
 * write_threads - Start NFSD, or report the configured number of threads
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 * Output:
 *      On success:     passed-in buffer filled with '\n'-terminated C
 *                      string numeric value representing the configured
 *                      number of NFSD threads;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing an unsigned
 *                                      integer value representing the
 *                                      number of NFSD threads to start
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     NFS service is started;
 *                      passed-in buffer filled with '\n'-terminated C
 *                      string numeric value representing the configured
 *                      number of NFSD threads;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero or a negative errno value
 */
static ssize_t write_threads(struct file *file, char *buf, size_t size)
{
        char *mesg = buf;
        int rv;
        struct net *net = netns(file);

        if (size > 0) {
                int newthreads;
                rv = get_int(&mesg, &newthreads);
                if (rv)
                        return rv;
                if (newthreads < 0)
                        return -EINVAL;
                trace_nfsd_ctl_threads(net, newthreads);
                mutex_lock(&nfsd_mutex);
                rv = nfsd_svc(1, &newthreads, net, file->f_cred, NULL);
                mutex_unlock(&nfsd_mutex);
                if (rv < 0)
                        return rv;
        } else
                rv = nfsd_nrthreads(net);

        return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%d\n", rv);
}

/*
 * write_pool_threads - Set or report the configured number of threads per pool
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing whitespace-
 *                                      separated unsigned integer values
 *                                      representing the number of NFSD
 *                                      threads to start in each pool
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     passed-in buffer filled with '\n'-terminated C
 *                      string containing integer values representing the
 *                      configured number of NFSD threads in each pool;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero or a negative errno value
 */
static ssize_t write_pool_threads(struct file *file, char *buf, size_t size)
{
        /* if size > 0, look for an array of number of threads per node
         * and apply them  then write out number of threads per node as reply
         */
        char *mesg = buf;
        int i;
        int rv;
        int len;
        int npools;
        int *nthreads;
        struct net *net = netns(file);

        mutex_lock(&nfsd_mutex);
        npools = nfsd_nrpools(net);
        if (npools == 0) {
                /*
                 * NFS is shut down.  The admin can start it by
                 * writing to the threads file but NOT the pool_threads
                 * file, sorry.  Report zero threads.
                 */
                mutex_unlock(&nfsd_mutex);
                strcpy(buf, "0\n");
                return strlen(buf);
        }

        nthreads = kzalloc_objs(int, npools);
        rv = -ENOMEM;
        if (nthreads == NULL)
                goto out_free;

        if (size > 0) {
                for (i = 0; i < npools; i++) {
                        rv = get_int(&mesg, &nthreads[i]);
                        if (rv == -ENOENT)
                                break;          /* fewer numbers than pools */
                        if (rv)
                                goto out_free;  /* syntax error */
                        rv = -EINVAL;
                        if (nthreads[i] < 0)
                                goto out_free;
                        trace_nfsd_ctl_pool_threads(net, i, nthreads[i]);
                }

                /*
                 * There must always be a thread in pool 0; the admin
                 * can't shut down NFS completely using pool_threads.
                 */
                if (nthreads[0] == 0)
                        nthreads[0] = 1;

                rv = nfsd_set_nrthreads(i, nthreads, net);
                if (rv)
                        goto out_free;
        }

        rv = nfsd_get_nrthreads(npools, nthreads, net);
        if (rv)
                goto out_free;

        mesg = buf;
        size = SIMPLE_TRANSACTION_LIMIT;
        for (i = 0; i < npools && size > 0; i++) {
                snprintf(mesg, size, "%d%c", nthreads[i], (i == npools-1 ? '\n' : ' '));
                len = strlen(mesg);
                size -= len;
                mesg += len;
        }
        rv = mesg - buf;
out_free:
        kfree(nthreads);
        mutex_unlock(&nfsd_mutex);
        return rv;
}

static ssize_t
nfsd_print_version_support(struct nfsd_net *nn, char *buf, int remaining,
                const char *sep, unsigned vers, int minor)
{
        const char *format = minor < 0 ? "%s%c%u" : "%s%c%u.%u";
        bool supported = !!nfsd_vers(nn, vers, NFSD_TEST);

        if (vers == 4 && minor >= 0 &&
            !nfsd_minorversion(nn, minor, NFSD_TEST))
                supported = false;
        if (minor == 0 && supported)
                /*
                 * special case for backward compatability.
                 * +4.0 is never reported, it is implied by
                 * +4, unless -4.0 is present.
                 */
                return 0;
        return snprintf(buf, remaining, format, sep,
                        supported ? '+' : '-', vers, minor);
}

static ssize_t __write_versions(struct file *file, char *buf, size_t size)
{
        char *mesg = buf;
        char *vers, *minorp, sign;
        int len, num, remaining;
        ssize_t tlen = 0;
        char *sep;
        struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

        if (size > 0) {
                if (nn->nfsd_serv)
                        /* Cannot change versions without updating
                         * nn->nfsd_serv->sv_xdrsize, and reallocing
                         * rq_argp and rq_resp
                         */
                        return -EBUSY;
                if (buf[size-1] != '\n')
                        return -EINVAL;
                buf[size-1] = 0;
                trace_nfsd_ctl_version(netns(file), buf);

                vers = mesg;
                len = qword_get(&mesg, vers, size);
                if (len <= 0) return -EINVAL;
                do {
                        enum vers_op cmd;
                        unsigned minor;
                        sign = *vers;
                        if (sign == '+' || sign == '-')
                                num = simple_strtol((vers+1), &minorp, 0);
                        else
                                num = simple_strtol(vers, &minorp, 0);
                        if (*minorp == '.') {
                                if (num != 4)
                                        return -EINVAL;
                                if (kstrtouint(minorp+1, 0, &minor) < 0)
                                        return -EINVAL;
                        }

                        cmd = sign == '-' ? NFSD_CLEAR : NFSD_SET;
                        switch(num) {
#ifdef CONFIG_NFSD_V2
                        case 2:
#endif
                        case 3:
                                nfsd_vers(nn, num, cmd);
                                break;
                        case 4:
                                if (*minorp == '.') {
                                        if (nfsd_minorversion(nn, minor, cmd) < 0)
                                                return -EINVAL;
                                } else if ((cmd == NFSD_SET) != nfsd_vers(nn, num, NFSD_TEST)) {
                                        /*
                                         * Either we have +4 and no minors are enabled,
                                         * or we have -4 and at least one minor is enabled.
                                         * In either case, propagate 'cmd' to all minors.
                                         */
                                        minor = 0;
                                        while (nfsd_minorversion(nn, minor, cmd) >= 0)
                                                minor++;
                                }
                                break;
                        default:
                                /* Ignore requests to disable non-existent versions */
                                if (cmd == NFSD_SET)
                                        return -EINVAL;
                        }
                        vers += len + 1;
                } while ((len = qword_get(&mesg, vers, size)) > 0);
                /* If all get turned off, turn them back on, as
                 * having no versions is BAD
                 */
                nfsd_reset_versions(nn);
        }

        /* Now write current state into reply buffer */
        sep = "";
        remaining = SIMPLE_TRANSACTION_LIMIT;
        for (num=2 ; num <= 4 ; num++) {
                int minor;
                if (!nfsd_vers(nn, num, NFSD_AVAIL))
                        continue;

                minor = -1;
                do {
                        len = nfsd_print_version_support(nn, buf, remaining,
                                        sep, num, minor);
                        if (len >= remaining)
                                goto out;
                        remaining -= len;
                        buf += len;
                        tlen += len;
                        minor++;
                        if (len)
                                sep = " ";
                } while (num == 4 && minor <= NFSD_SUPPORTED_MINOR_VERSION);
        }
out:
        len = snprintf(buf, remaining, "\n");
        if (len >= remaining)
                return -EINVAL;
        return tlen + len;
}

/*
 * write_versions - Set or report the available NFS protocol versions
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 * Output:
 *      On success:     passed-in buffer filled with '\n'-terminated C
 *                      string containing positive or negative integer
 *                      values representing the current status of each
 *                      protocol version;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero or a negative errno value
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing whitespace-
 *                                      separated positive or negative
 *                                      integer values representing NFS
 *                                      protocol versions to enable ("+n")
 *                                      or disable ("-n")
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     status of zero or more protocol versions has
 *                      been updated; passed-in buffer filled with
 *                      '\n'-terminated C string containing positive
 *                      or negative integer values representing the
 *                      current status of each protocol version;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero or a negative errno value
 */
static ssize_t write_versions(struct file *file, char *buf, size_t size)
{
        ssize_t rv;

        mutex_lock(&nfsd_mutex);
        rv = __write_versions(file, buf, size);
        mutex_unlock(&nfsd_mutex);
        return rv;
}

/*
 * Zero-length write.  Return a list of NFSD's current listener
 * transports.
 */
static ssize_t __write_ports_names(char *buf, struct net *net)
{
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);

        if (nn->nfsd_serv == NULL)
                return 0;
        return svc_xprt_names(nn->nfsd_serv, buf, SIMPLE_TRANSACTION_LIMIT);
}

/*
 * A single 'fd' number was written, in which case it must be for
 * a socket of a supported family/protocol, and we use it as an
 * nfsd listener.
 */
static ssize_t __write_ports_addfd(char *buf, struct net *net, const struct cred *cred)
{
        char *mesg = buf;
        int fd, err;
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
        struct svc_serv *serv;

        err = get_int(&mesg, &fd);
        if (err != 0 || fd < 0)
                return -EINVAL;
        trace_nfsd_ctl_ports_addfd(net, fd);

        err = nfsd_create_serv(net);
        if (err != 0)
                return err;

        serv = nn->nfsd_serv;
        err = svc_addsock(serv, net, fd, buf, SIMPLE_TRANSACTION_LIMIT, cred);

        if (!serv->sv_nrthreads && list_empty(&nn->nfsd_serv->sv_permsocks))
                nfsd_destroy_serv(net);

        return err;
}

/*
 * A transport listener is added by writing its transport name and
 * a port number.
 */
static ssize_t __write_ports_addxprt(char *buf, struct net *net, const struct cred *cred)
{
        char transport[16];
        struct svc_xprt *xprt;
        int port, err;
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
        struct svc_serv *serv;

        if (sscanf(buf, "%15s %5u", transport, &port) != 2)
                return -EINVAL;

        if (port < 1 || port > USHRT_MAX)
                return -EINVAL;
        trace_nfsd_ctl_ports_addxprt(net, transport, port);

        err = nfsd_create_serv(net);
        if (err != 0)
                return err;

        serv = nn->nfsd_serv;
        err = svc_xprt_create(serv, transport, net,
                              PF_INET, port, SVC_SOCK_ANONYMOUS, cred);
        if (err < 0)
                goto out_err;

        err = svc_xprt_create(serv, transport, net,
                              PF_INET6, port, SVC_SOCK_ANONYMOUS, cred);
        if (err < 0 && err != -EAFNOSUPPORT)
                goto out_close;

        return 0;
out_close:
        xprt = svc_find_xprt(serv, transport, net, PF_INET, port);
        if (xprt != NULL) {
                svc_xprt_close(xprt);
                svc_xprt_put(xprt);
        }
out_err:
        if (!serv->sv_nrthreads && list_empty(&nn->nfsd_serv->sv_permsocks))
                nfsd_destroy_serv(net);

        return err;
}

static ssize_t __write_ports(struct file *file, char *buf, size_t size,
                             struct net *net)
{
        if (size == 0)
                return __write_ports_names(buf, net);

        if (isdigit(buf[0]))
                return __write_ports_addfd(buf, net, file->f_cred);

        if (isalpha(buf[0]))
                return __write_ports_addxprt(buf, net, file->f_cred);

        return -EINVAL;
}

/*
 * write_ports - Pass a socket file descriptor or transport name to listen on
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 * Output:
 *      On success:     passed-in buffer filled with a '\n'-terminated C
 *                      string containing a whitespace-separated list of
 *                      named NFSD listeners;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero or a negative errno value
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing an unsigned
 *                                      integer value representing a bound
 *                                      but unconnected socket that is to be
 *                                      used as an NFSD listener; listen(3)
 *                                      must be called for a SOCK_STREAM
 *                                      socket, otherwise it is ignored
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     NFS service is started;
 *                      passed-in buffer filled with a '\n'-terminated C
 *                      string containing a unique alphanumeric name of
 *                      the listener;
 *                      return code is the size in bytes of the string
 *      On error:       return code is a negative errno value
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing a transport
 *                                      name and an unsigned integer value
 *                                      representing the port to listen on,
 *                                      separated by whitespace
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     returns zero; NFS service is started
 *      On error:       return code is a negative errno value
 */
static ssize_t write_ports(struct file *file, char *buf, size_t size)
{
        ssize_t rv;

        mutex_lock(&nfsd_mutex);
        rv = __write_ports(file, buf, size, netns(file));
        mutex_unlock(&nfsd_mutex);
        return rv;
}


int nfsd_max_blksize;

/*
 * write_maxblksize - Set or report the current NFS blksize
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing an unsigned
 *                                      integer value representing the new
 *                                      NFS blksize
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     passed-in buffer filled with '\n'-terminated C string
 *                      containing numeric value of the current NFS blksize
 *                      setting;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero or a negative errno value
 */
static ssize_t write_maxblksize(struct file *file, char *buf, size_t size)
{
        char *mesg = buf;
        struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

        if (size > 0) {
                int bsize;
                int rv = get_int(&mesg, &bsize);
                if (rv)
                        return rv;
                trace_nfsd_ctl_maxblksize(netns(file), bsize);

                /* force bsize into allowed range and
                 * required alignment.
                 */
                bsize = max_t(int, bsize, 1024);
                bsize = min_t(int, bsize, NFSSVC_MAXBLKSIZE);
                bsize &= ~(1024-1);
                mutex_lock(&nfsd_mutex);
                if (nn->nfsd_serv) {
                        mutex_unlock(&nfsd_mutex);
                        return -EBUSY;
                }
                nfsd_max_blksize = bsize;
                mutex_unlock(&nfsd_mutex);
        }

        return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%d\n",
                                                        nfsd_max_blksize);
}

#ifdef CONFIG_NFSD_V4
static ssize_t __nfsd4_write_time(struct file *file, char *buf, size_t size,
                                  time64_t *time, struct nfsd_net *nn)
{
        struct dentry *dentry = file_dentry(file);
        char *mesg = buf;
        int rv, i;

        if (size > 0) {
                if (nn->nfsd_serv)
                        return -EBUSY;
                rv = get_int(&mesg, &i);
                if (rv)
                        return rv;
                trace_nfsd_ctl_time(netns(file), dentry->d_name.name,
                                    dentry->d_name.len, i);

                /*
                 * Some sanity checking.  We don't have a reason for
                 * these particular numbers, but problems with the
                 * extremes are:
                 *      - Too short: the briefest network outage may
                 *        cause clients to lose all their locks.  Also,
                 *        the frequent polling may be wasteful.
                 *      - Too long: do you really want reboot recovery
                 *        to take more than an hour?  Or to make other
                 *        clients wait an hour before being able to
                 *        revoke a dead client's locks?
                 */
                if (i < 10 || i > 3600)
                        return -EINVAL;
                *time = i;
        }

        return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%lld\n", *time);
}

static ssize_t nfsd4_write_time(struct file *file, char *buf, size_t size,
                                time64_t *time, struct nfsd_net *nn)
{
        ssize_t rv;

        mutex_lock(&nfsd_mutex);
        rv = __nfsd4_write_time(file, buf, size, time, nn);
        mutex_unlock(&nfsd_mutex);
        return rv;
}

/*
 * write_leasetime - Set or report the current NFSv4 lease time
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing an unsigned
 *                                      integer value representing the new
 *                                      NFSv4 lease expiry time
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     passed-in buffer filled with '\n'-terminated C
 *                      string containing unsigned integer value of the
 *                      current lease expiry time;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero or a negative errno value
 */
static ssize_t write_leasetime(struct file *file, char *buf, size_t size)
{
        struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);
        return nfsd4_write_time(file, buf, size, &nn->nfsd4_lease, nn);
}

/*
 * write_gracetime - Set or report current NFSv4 grace period time
 *
 * As above, but sets the time of the NFSv4 grace period.
 *
 * Note this should never be set to less than the *previous*
 * lease-period time, but we don't try to enforce this.  (In the common
 * case (a new boot), we don't know what the previous lease time was
 * anyway.)
 */
static ssize_t write_gracetime(struct file *file, char *buf, size_t size)
{
        struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);
        return nfsd4_write_time(file, buf, size, &nn->nfsd4_grace, nn);
}

#ifdef CONFIG_NFSD_LEGACY_CLIENT_TRACKING
static ssize_t __write_recoverydir(struct file *file, char *buf, size_t size,
                                   struct nfsd_net *nn)
{
        char *mesg = buf;
        char *recdir;
        int len, status;

        if (size > 0) {
                if (nn->nfsd_serv)
                        return -EBUSY;
                if (size > PATH_MAX || buf[size-1] != '\n')
                        return -EINVAL;
                buf[size-1] = 0;

                recdir = mesg;
                len = qword_get(&mesg, recdir, size);
                if (len <= 0)
                        return -EINVAL;
                trace_nfsd_ctl_recoverydir(netns(file), recdir);

                status = nfs4_reset_recoverydir(recdir);
                if (status)
                        return status;
        }

        return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%s\n",
                                                        nfs4_recoverydir());
}

/*
 * write_recoverydir - Set or report the pathname of the recovery directory
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing the pathname
 *                                      of the directory on a local file
 *                                      system containing permanent NFSv4
 *                                      recovery data
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     passed-in buffer filled with '\n'-terminated C string
 *                      containing the current recovery pathname setting;
 *                      return code is the size in bytes of the string
 *      On error:       return code is zero or a negative errno value
 */
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size)
{
        ssize_t rv;
        struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

        mutex_lock(&nfsd_mutex);
        rv = __write_recoverydir(file, buf, size, nn);
        mutex_unlock(&nfsd_mutex);
        return rv;
}
#endif

/*
 * write_v4_end_grace - release grace period for nfsd's v4.x lock manager
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 * OR
 *
 * Input:
 *                      buf:            any value
 *                      size:           non-zero length of C string in @buf
 * Output:
 *                      passed-in buffer filled with "Y" or "N" with a newline
 *                      and NULL-terminated C string. This indicates whether
 *                      the grace period has ended in the current net
 *                      namespace. Return code is the size in bytes of the
 *                      string. Writing a string that starts with 'Y', 'y', or
 *                      '1' to the file will end the grace period for nfsd's v4
 *                      lock manager.
 */
static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size)
{
        struct nfsd_net *nn = net_generic(netns(file), nfsd_net_id);

        if (size > 0) {
                switch(buf[0]) {
                case 'Y':
                case 'y':
                case '1':
                        if (!nfsd4_force_end_grace(nn))
                                return -EBUSY;
                        trace_nfsd_end_grace(netns(file));
                        break;
                default:
                        return -EINVAL;
                }
        }

        return scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, "%c\n",
                         nn->grace_ended ? 'Y' : 'N');
}

#endif

/*----------------------------------------------------------------------------*/
/*
 *      populating the filesystem.
 */

static struct inode *nfsd_get_inode(struct super_block *sb, umode_t mode)
{
        struct inode *inode = new_inode(sb);
        if (inode) {
                /* Following advice from simple_fill_super documentation: */
                inode->i_ino = iunique(sb, NFSD_MaxReserved);
                inode->i_mode = mode;
                simple_inode_init_ts(inode);
        }
        return inode;
}

static struct dentry *nfsd_mkdir(struct dentry *parent, struct nfsdfs_client *ncl, char *name)
{
        struct inode *dir = parent->d_inode;
        struct dentry *dentry;
        struct inode *inode;

        inode = nfsd_get_inode(parent->d_sb, S_IFDIR | 0600);
        if (!inode)
                return ERR_PTR(-ENOMEM);

        dentry = simple_start_creating(parent, name);
        if (IS_ERR(dentry)) {
                iput(inode);
                return dentry;
        }
        inode->i_fop = &simple_dir_operations;
        inode->i_op = &simple_dir_inode_operations;
        inc_nlink(inode);
        if (ncl) {
                inode->i_private = ncl;
                kref_get(&ncl->cl_ref);
        }
        d_make_persistent(dentry, inode);
        inc_nlink(dir);
        fsnotify_mkdir(dir, dentry);
        simple_done_creating(dentry);
        return dentry;  // borrowed
}

#if IS_ENABLED(CONFIG_SUNRPC_GSS)
/*
 * @content is assumed to be a NUL-terminated string that lives
 * longer than the symlink itself.
 */
static void _nfsd_symlink(struct dentry *parent, const char *name,
                          const char *content)
{
        struct inode *dir = parent->d_inode;
        struct inode *inode;
        struct dentry *dentry;

        inode = nfsd_get_inode(dir->i_sb, S_IFLNK | 0777);
        if (!inode)
                return;

        dentry = simple_start_creating(parent, name);
        if (IS_ERR(dentry)) {
                iput(inode);
                return;
        }

        inode->i_op = &simple_symlink_inode_operations;
        inode->i_link = (char *)content;
        inode->i_size = strlen(content);

        d_make_persistent(dentry, inode);
        fsnotify_create(dir, dentry);
        simple_done_creating(dentry);
}
#else
static inline void _nfsd_symlink(struct dentry *parent, const char *name,
                                 const char *content)
{
}

#endif

static void clear_ncl(struct dentry *dentry)
{
        struct inode *inode = d_inode(dentry);
        struct nfsdfs_client *ncl = inode->i_private;

        spin_lock(&inode->i_lock);
        inode->i_private = NULL;
        spin_unlock(&inode->i_lock);
        kref_put(&ncl->cl_ref, ncl->cl_release);
}

struct nfsdfs_client *get_nfsdfs_client(struct inode *inode)
{
        struct nfsdfs_client *nc;

        spin_lock(&inode->i_lock);
        nc = inode->i_private;
        if (nc)
                kref_get(&nc->cl_ref);
        spin_unlock(&inode->i_lock);
        return nc;
}

/* XXX: cut'n'paste from simple_fill_super; figure out if we could share
 * code instead. */
static int nfsdfs_create_files(struct dentry *root,
                                const struct tree_descr *files,
                                struct nfsdfs_client *ncl,
                                struct dentry **fdentries)
{
        struct inode *dir = d_inode(root);
        struct dentry *dentry;

        for (int i = 0; files->name && files->name[0]; i++, files++) {
                struct inode *inode = nfsd_get_inode(root->d_sb,
                                                     S_IFREG | files->mode);
                if (!inode)
                        return -ENOMEM;
                dentry = simple_start_creating(root, files->name);
                if (IS_ERR(dentry)) {
                        iput(inode);
                        return PTR_ERR(dentry);
                }
                kref_get(&ncl->cl_ref);
                inode->i_fop = files->ops;
                inode->i_private = ncl;
                d_make_persistent(dentry, inode);
                fsnotify_create(dir, dentry);
                if (fdentries)
                        fdentries[i] = dentry; // borrowed
                simple_done_creating(dentry);
        }
        return 0;
}

/* on success, returns positive number unique to that client. */
struct dentry *nfsd_client_mkdir(struct nfsd_net *nn,
                                 struct nfsdfs_client *ncl, u32 id,
                                 const struct tree_descr *files,
                                 struct dentry **fdentries)
{
        struct dentry *dentry;
        char name[11];
        int ret;

        sprintf(name, "%u", id);

        dentry = nfsd_mkdir(nn->nfsd_client_dir, ncl, name);
        if (IS_ERR(dentry)) /* XXX: tossing errors? */
                return NULL;
        ret = nfsdfs_create_files(dentry, files, ncl, fdentries);
        if (ret) {
                nfsd_client_rmdir(dentry);
                return NULL;
        }
        return dentry;
}

/* Taken from __rpc_rmdir: */
void nfsd_client_rmdir(struct dentry *dentry)
{
        simple_recursive_removal(dentry, clear_ncl);
}

static int nfsd_fill_super(struct super_block *sb, struct fs_context *fc)
{
        struct nfsd_net *nn = net_generic(current->nsproxy->net_ns,
                                                        nfsd_net_id);
        struct dentry *dentry;
        int ret;

        static const struct tree_descr nfsd_files[] = {
                [NFSD_List] = {"exports", &exports_nfsd_operations, S_IRUGO},
                /* Per-export io stats use same ops as exports file */
                [NFSD_Export_Stats] = {"export_stats", &exports_nfsd_operations, S_IRUGO},
                [NFSD_Export_features] = {"export_features",
                                        &export_features_fops, S_IRUGO},
                [NFSD_FO_UnlockIP] = {"unlock_ip",
                                        &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_FO_UnlockFS] = {"unlock_filesystem",
                                        &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Pool_Stats] = {"pool_stats", &pool_stats_operations, S_IRUGO},
                [NFSD_Reply_Cache_Stats] = {"reply_cache_stats",
                                        &nfsd_reply_cache_stats_fops, S_IRUGO},
                [NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO},
                [NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO},
                [NFSD_Filecache] = {"filecache", &nfsd_file_cache_stats_fops, S_IRUGO},
#ifdef CONFIG_NFSD_V4
                [NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Gracetime] = {"nfsv4gracetime", &transaction_ops, S_IWUSR|S_IRUSR},
#ifdef CONFIG_NFSD_LEGACY_CLIENT_TRACKING
                [NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},
#endif
                [NFSD_V4EndGrace] = {"v4_end_grace", &transaction_ops, S_IWUSR|S_IRUGO},
#endif
                /* last one */ {""}
        };

        ret = simple_fill_super(sb, 0x6e667364, nfsd_files);
        if (ret)
                return ret;
        _nfsd_symlink(sb->s_root, "supported_krb5_enctypes",
                      "/proc/net/rpc/gss_krb5_enctypes");
        dentry = nfsd_mkdir(sb->s_root, NULL, "clients");
        if (IS_ERR(dentry))
                return PTR_ERR(dentry);
        nn->nfsd_client_dir = dentry;
        return 0;
}

static int nfsd_fs_get_tree(struct fs_context *fc)
{
        return get_tree_keyed(fc, nfsd_fill_super, get_net(fc->net_ns));
}

static void nfsd_fs_free_fc(struct fs_context *fc)
{
        if (fc->s_fs_info)
                put_net(fc->s_fs_info);
}

static const struct fs_context_operations nfsd_fs_context_ops = {
        .free           = nfsd_fs_free_fc,
        .get_tree       = nfsd_fs_get_tree,
};

static int nfsd_init_fs_context(struct fs_context *fc)
{
        put_user_ns(fc->user_ns);
        fc->user_ns = get_user_ns(fc->net_ns->user_ns);
        fc->ops = &nfsd_fs_context_ops;
        return 0;
}

static void nfsd_umount(struct super_block *sb)
{
        struct net *net = sb->s_fs_info;

        nfsd_shutdown_threads(net);

        kill_anon_super(sb);
        put_net(net);
}

static struct file_system_type nfsd_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "nfsd",
        .init_fs_context = nfsd_init_fs_context,
        .kill_sb        = nfsd_umount,
};
MODULE_ALIAS_FS("nfsd");

#ifdef CONFIG_PROC_FS

static int exports_proc_open(struct inode *inode, struct file *file)
{
        return exports_net_open(current->nsproxy->net_ns, file);
}

static const struct proc_ops exports_proc_ops = {
        .proc_open      = exports_proc_open,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_release   = exports_release,
};

static int create_proc_exports_entry(void)
{
        struct proc_dir_entry *entry;

        entry = proc_mkdir("fs/nfs", NULL);
        if (!entry)
                return -ENOMEM;
        entry = proc_create("exports", 0, entry, &exports_proc_ops);
        if (!entry) {
                remove_proc_entry("fs/nfs", NULL);
                return -ENOMEM;
        }
        return 0;
}
#else /* CONFIG_PROC_FS */
static int create_proc_exports_entry(void)
{
        return 0;
}
#endif

unsigned int nfsd_net_id;

static int nfsd_genl_rpc_status_compose_msg(struct sk_buff *skb,
                                            struct netlink_callback *cb,
                                            struct nfsd_genl_rqstp *genl_rqstp)
{
        void *hdr;
        u32 i;

        hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
                          &nfsd_nl_family, 0, NFSD_CMD_RPC_STATUS_GET);
        if (!hdr)
                return -ENOBUFS;

        if (nla_put_be32(skb, NFSD_A_RPC_STATUS_XID, genl_rqstp->rq_xid) ||
            nla_put_u32(skb, NFSD_A_RPC_STATUS_FLAGS, genl_rqstp->rq_flags) ||
            nla_put_u32(skb, NFSD_A_RPC_STATUS_PROG, genl_rqstp->rq_prog) ||
            nla_put_u32(skb, NFSD_A_RPC_STATUS_PROC, genl_rqstp->rq_proc) ||
            nla_put_u8(skb, NFSD_A_RPC_STATUS_VERSION, genl_rqstp->rq_vers) ||
            nla_put_s64(skb, NFSD_A_RPC_STATUS_SERVICE_TIME,
                        ktime_to_us(genl_rqstp->rq_stime),
                        NFSD_A_RPC_STATUS_PAD))
                return -ENOBUFS;

        switch (genl_rqstp->rq_saddr.sa_family) {
        case AF_INET: {
                const struct sockaddr_in *s_in, *d_in;

                s_in = (const struct sockaddr_in *)&genl_rqstp->rq_saddr;
                d_in = (const struct sockaddr_in *)&genl_rqstp->rq_daddr;
                if (nla_put_in_addr(skb, NFSD_A_RPC_STATUS_SADDR4,
                                    s_in->sin_addr.s_addr) ||
                    nla_put_in_addr(skb, NFSD_A_RPC_STATUS_DADDR4,
                                    d_in->sin_addr.s_addr) ||
                    nla_put_be16(skb, NFSD_A_RPC_STATUS_SPORT,
                                 s_in->sin_port) ||
                    nla_put_be16(skb, NFSD_A_RPC_STATUS_DPORT,
                                 d_in->sin_port))
                        return -ENOBUFS;
                break;
        }
        case AF_INET6: {
                const struct sockaddr_in6 *s_in, *d_in;

                s_in = (const struct sockaddr_in6 *)&genl_rqstp->rq_saddr;
                d_in = (const struct sockaddr_in6 *)&genl_rqstp->rq_daddr;
                if (nla_put_in6_addr(skb, NFSD_A_RPC_STATUS_SADDR6,
                                     &s_in->sin6_addr) ||
                    nla_put_in6_addr(skb, NFSD_A_RPC_STATUS_DADDR6,
                                     &d_in->sin6_addr) ||
                    nla_put_be16(skb, NFSD_A_RPC_STATUS_SPORT,
                                 s_in->sin6_port) ||
                    nla_put_be16(skb, NFSD_A_RPC_STATUS_DPORT,
                                 d_in->sin6_port))
                        return -ENOBUFS;
                break;
        }
        }

        for (i = 0; i < genl_rqstp->rq_opcnt; i++)
                if (nla_put_u32(skb, NFSD_A_RPC_STATUS_COMPOUND_OPS,
                                genl_rqstp->rq_opnum[i]))
                        return -ENOBUFS;

        genlmsg_end(skb, hdr);
        return 0;
}

/**
 * nfsd_nl_rpc_status_get_dumpit - Handle rpc_status_get dumpit
 * @skb: reply buffer
 * @cb: netlink metadata and command arguments
 *
 * Returns the size of the reply or a negative errno.
 */
int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
                                  struct netlink_callback *cb)
{
        int i, ret, rqstp_index = 0;
        struct nfsd_net *nn;

        mutex_lock(&nfsd_mutex);

        nn = net_generic(sock_net(skb->sk), nfsd_net_id);
        if (!nn->nfsd_serv) {
                ret = -ENODEV;
                goto out_unlock;
        }

        rcu_read_lock();

        for (i = 0; i < nn->nfsd_serv->sv_nrpools; i++) {
                struct svc_rqst *rqstp;

                if (i < cb->args[0]) /* already consumed */
                        continue;

                rqstp_index = 0;
                list_for_each_entry_rcu(rqstp,
                                &nn->nfsd_serv->sv_pools[i].sp_all_threads,
                                rq_all) {
                        struct nfsd_genl_rqstp genl_rqstp;
                        unsigned int status_counter;

                        if (rqstp_index++ < cb->args[1]) /* already consumed */
                                continue;
                        /*
                         * Acquire rq_status_counter before parsing the rqst
                         * fields. rq_status_counter is set to an odd value in
                         * order to notify the consumers the rqstp fields are
                         * meaningful.
                         */
                        status_counter =
                                smp_load_acquire(&rqstp->rq_status_counter);
                        if (!(status_counter & 1))
                                continue;

                        genl_rqstp.rq_xid = rqstp->rq_xid;
                        genl_rqstp.rq_flags = rqstp->rq_flags;
                        genl_rqstp.rq_vers = rqstp->rq_vers;
                        genl_rqstp.rq_prog = rqstp->rq_prog;
                        genl_rqstp.rq_proc = rqstp->rq_proc;
                        genl_rqstp.rq_stime = rqstp->rq_stime;
                        genl_rqstp.rq_opcnt = 0;
                        memcpy(&genl_rqstp.rq_daddr, svc_daddr(rqstp),
                               sizeof(struct sockaddr));
                        memcpy(&genl_rqstp.rq_saddr, svc_addr(rqstp),
                               sizeof(struct sockaddr));

#ifdef CONFIG_NFSD_V4
                        if (rqstp->rq_vers == NFS4_VERSION &&
                            rqstp->rq_proc == NFSPROC4_COMPOUND) {
                                /* NFSv4 compound */
                                struct nfsd4_compoundargs *args;
                                int j;

                                args = rqstp->rq_argp;
                                genl_rqstp.rq_opcnt = min_t(u32, args->opcnt,
                                                            ARRAY_SIZE(genl_rqstp.rq_opnum));
                                for (j = 0; j < genl_rqstp.rq_opcnt; j++)
                                        genl_rqstp.rq_opnum[j] =
                                                args->ops[j].opnum;
                        }
#endif /* CONFIG_NFSD_V4 */

                        /*
                         * Acquire rq_status_counter before reporting the rqst
                         * fields to the user.
                         */
                        if (smp_load_acquire(&rqstp->rq_status_counter) !=
                            status_counter)
                                continue;

                        ret = nfsd_genl_rpc_status_compose_msg(skb, cb,
                                                               &genl_rqstp);
                        if (ret)
                                goto out;
                }
        }

        cb->args[0] = i;
        cb->args[1] = rqstp_index;
        ret = skb->len;
out:
        rcu_read_unlock();
out_unlock:
        mutex_unlock(&nfsd_mutex);

        return ret;
}

/**
 * nfsd_nl_threads_set_doit - set the number of running threads
 * @skb: reply buffer
 * @info: netlink metadata and command arguments
 *
 * Return 0 on success or a negative errno.
 */
int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
{
        int *nthreads, nrpools = 0, i, ret = -EOPNOTSUPP, rem;
        struct net *net = genl_info_net(info);
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
        const struct nlattr *attr;
        const char *scope = NULL;

        if (GENL_REQ_ATTR_CHECK(info, NFSD_A_SERVER_THREADS))
                return -EINVAL;

        /* count number of SERVER_THREADS values */
        nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_THREADS, info->nlhdr,
                                 GENL_HDRLEN, rem)
                nrpools++;

        mutex_lock(&nfsd_mutex);

        nthreads = kzalloc_objs(int, nrpools);
        if (!nthreads) {
                ret = -ENOMEM;
                goto out_unlock;
        }

        i = 0;
        nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_THREADS, info->nlhdr,
                                 GENL_HDRLEN, rem) {
                nthreads[i++] = nla_get_u32(attr);
                if (i >= nrpools)
                        break;
        }

        if (info->attrs[NFSD_A_SERVER_GRACETIME] ||
            info->attrs[NFSD_A_SERVER_LEASETIME] ||
            info->attrs[NFSD_A_SERVER_SCOPE]) {
                ret = -EBUSY;
                if (nn->nfsd_serv && nn->nfsd_serv->sv_nrthreads)
                        goto out_unlock;

                ret = -EINVAL;
                attr = info->attrs[NFSD_A_SERVER_GRACETIME];
                if (attr) {
                        u32 gracetime = nla_get_u32(attr);

                        if (gracetime < 10 || gracetime > 3600)
                                goto out_unlock;

                        nn->nfsd4_grace = gracetime;
                }

                attr = info->attrs[NFSD_A_SERVER_LEASETIME];
                if (attr) {
                        u32 leasetime = nla_get_u32(attr);

                        if (leasetime < 10 || leasetime > 3600)
                                goto out_unlock;

                        nn->nfsd4_lease = leasetime;
                }

                attr = info->attrs[NFSD_A_SERVER_SCOPE];
                if (attr)
                        scope = nla_data(attr);
        }

        attr = info->attrs[NFSD_A_SERVER_MIN_THREADS];
        if (attr)
                nn->min_threads = nla_get_u32(attr);

        ret = nfsd_svc(nrpools, nthreads, net, current_cred(), scope);
        if (ret > 0)
                ret = 0;
out_unlock:
        mutex_unlock(&nfsd_mutex);
        kfree(nthreads);
        return ret;
}

/**
 * nfsd_nl_threads_get_doit - get the maximum number of running threads
 * @skb: reply buffer
 * @info: netlink metadata and command arguments
 *
 * Return 0 on success or a negative errno.
 */
int nfsd_nl_threads_get_doit(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = genl_info_net(info);
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
        void *hdr;
        int err;

        skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        hdr = genlmsg_iput(skb, info);
        if (!hdr) {
                err = -EMSGSIZE;
                goto err_free_msg;
        }

        mutex_lock(&nfsd_mutex);

        err = nla_put_u32(skb, NFSD_A_SERVER_GRACETIME,
                          nn->nfsd4_grace) ||
              nla_put_u32(skb, NFSD_A_SERVER_LEASETIME,
                          nn->nfsd4_lease) ||
              nla_put_u32(skb, NFSD_A_SERVER_MIN_THREADS,
                          nn->min_threads) ||
              nla_put_string(skb, NFSD_A_SERVER_SCOPE,
                          nn->nfsd_name);
        if (err)
                goto err_unlock;

        if (nn->nfsd_serv) {
                int i;

                for (i = 0; i < nfsd_nrpools(net); ++i) {
                        struct svc_pool *sp = &nn->nfsd_serv->sv_pools[i];

                        err = nla_put_u32(skb, NFSD_A_SERVER_THREADS,
                                          sp->sp_nrthrmax);
                        if (err)
                                goto err_unlock;
                }
        } else {
                err = nla_put_u32(skb, NFSD_A_SERVER_THREADS, 0);
                if (err)
                        goto err_unlock;
        }

        mutex_unlock(&nfsd_mutex);

        genlmsg_end(skb, hdr);

        return genlmsg_reply(skb, info);

err_unlock:
        mutex_unlock(&nfsd_mutex);
err_free_msg:
        nlmsg_free(skb);

        return err;
}

/**
 * nfsd_nl_version_set_doit - set the nfs enabled versions
 * @skb: reply buffer
 * @info: netlink metadata and command arguments
 *
 * Return 0 on success or a negative errno.
 */
int nfsd_nl_version_set_doit(struct sk_buff *skb, struct genl_info *info)
{
        const struct nlattr *attr;
        struct nfsd_net *nn;
        int i, rem;

        if (GENL_REQ_ATTR_CHECK(info, NFSD_A_SERVER_PROTO_VERSION))
                return -EINVAL;

        mutex_lock(&nfsd_mutex);

        nn = net_generic(genl_info_net(info), nfsd_net_id);
        if (nn->nfsd_serv) {
                mutex_unlock(&nfsd_mutex);
                return -EBUSY;
        }

        /* clear current supported versions. */
        nfsd_vers(nn, 2, NFSD_CLEAR);
        nfsd_vers(nn, 3, NFSD_CLEAR);
        for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++)
                nfsd_minorversion(nn, i, NFSD_CLEAR);

        nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_PROTO_VERSION, info->nlhdr,
                                 GENL_HDRLEN, rem) {
                struct nlattr *tb[NFSD_A_VERSION_MAX + 1];
                u32 major, minor = 0;
                bool enabled;

                if (nla_parse_nested(tb, NFSD_A_VERSION_MAX, attr,
                                     nfsd_version_nl_policy, info->extack) < 0)
                        continue;

                if (!tb[NFSD_A_VERSION_MAJOR])
                        continue;

                major = nla_get_u32(tb[NFSD_A_VERSION_MAJOR]);
                if (tb[NFSD_A_VERSION_MINOR])
                        minor = nla_get_u32(tb[NFSD_A_VERSION_MINOR]);

                enabled = nla_get_flag(tb[NFSD_A_VERSION_ENABLED]);

                switch (major) {
                case 4:
                        nfsd_minorversion(nn, minor, enabled ? NFSD_SET : NFSD_CLEAR);
                        break;
                case 3:
                case 2:
                        if (!minor)
                                nfsd_vers(nn, major, enabled ? NFSD_SET : NFSD_CLEAR);
                        break;
                default:
                        break;
                }
        }

        mutex_unlock(&nfsd_mutex);

        return 0;
}

/**
 * nfsd_nl_version_get_doit - get the enabled status for all supported nfs versions
 * @skb: reply buffer
 * @info: netlink metadata and command arguments
 *
 * Return 0 on success or a negative errno.
 */
int nfsd_nl_version_get_doit(struct sk_buff *skb, struct genl_info *info)
{
        struct nfsd_net *nn;
        int i, err;
        void *hdr;

        skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        hdr = genlmsg_iput(skb, info);
        if (!hdr) {
                err = -EMSGSIZE;
                goto err_free_msg;
        }

        mutex_lock(&nfsd_mutex);
        nn = net_generic(genl_info_net(info), nfsd_net_id);

        for (i = 2; i <= 4; i++) {
                int j;

                for (j = 0; j <= NFSD_SUPPORTED_MINOR_VERSION; j++) {
                        struct nlattr *attr;

                        /* Don't record any versions the kernel doesn't have
                         * compiled in
                         */
                        if (!nfsd_support_version(i))
                                continue;

                        /* NFSv{2,3} does not support minor numbers */
                        if (i < 4 && j)
                                continue;

                        attr = nla_nest_start(skb,
                                              NFSD_A_SERVER_PROTO_VERSION);
                        if (!attr) {
                                err = -EINVAL;
                                goto err_nfsd_unlock;
                        }

                        if (nla_put_u32(skb, NFSD_A_VERSION_MAJOR, i) ||
                            nla_put_u32(skb, NFSD_A_VERSION_MINOR, j)) {
                                err = -EINVAL;
                                goto err_nfsd_unlock;
                        }

                        /* Set the enabled flag if the version is enabled */
                        if (nfsd_vers(nn, i, NFSD_TEST) &&
                            (i < 4 || nfsd_minorversion(nn, j, NFSD_TEST)) &&
                            nla_put_flag(skb, NFSD_A_VERSION_ENABLED)) {
                                err = -EINVAL;
                                goto err_nfsd_unlock;
                        }

                        nla_nest_end(skb, attr);
                }
        }

        mutex_unlock(&nfsd_mutex);
        genlmsg_end(skb, hdr);

        return genlmsg_reply(skb, info);

err_nfsd_unlock:
        mutex_unlock(&nfsd_mutex);
err_free_msg:
        nlmsg_free(skb);

        return err;
}

/**
 * nfsd_nl_listener_set_doit - set the nfs running sockets
 * @skb: reply buffer
 * @info: netlink metadata and command arguments
 *
 * Return 0 on success or a negative errno.
 */
int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = genl_info_net(info);
        struct svc_xprt *xprt, *tmp;
        const struct nlattr *attr;
        struct svc_serv *serv;
        LIST_HEAD(permsocks);
        struct nfsd_net *nn;
        bool delete = false;
        int err, rem;

        mutex_lock(&nfsd_mutex);

        err = nfsd_create_serv(net);
        if (err) {
                mutex_unlock(&nfsd_mutex);
                return err;
        }

        nn = net_generic(net, nfsd_net_id);
        serv = nn->nfsd_serv;

        spin_lock_bh(&serv->sv_lock);

        /* Move all of the old listener sockets to a temp list */
        list_splice_init(&serv->sv_permsocks, &permsocks);

        /*
         * Walk the list of server_socks from userland and move any that match
         * back to sv_permsocks
         */
        nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr,
                                 GENL_HDRLEN, rem) {
                struct nlattr *tb[NFSD_A_SOCK_MAX + 1];
                const char *xcl_name;
                struct sockaddr *sa;

                if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
                                     nfsd_sock_nl_policy, info->extack) < 0)
                        continue;

                if (!tb[NFSD_A_SOCK_ADDR] || !tb[NFSD_A_SOCK_TRANSPORT_NAME])
                        continue;

                if (nla_len(tb[NFSD_A_SOCK_ADDR]) < sizeof(*sa))
                        continue;

                xcl_name = nla_data(tb[NFSD_A_SOCK_TRANSPORT_NAME]);
                sa = nla_data(tb[NFSD_A_SOCK_ADDR]);

                /* Put back any matching sockets */
                list_for_each_entry_safe(xprt, tmp, &permsocks, xpt_list) {
                        /* This shouldn't be possible */
                        if (WARN_ON_ONCE(xprt->xpt_net != net)) {
                                list_move(&xprt->xpt_list, &serv->sv_permsocks);
                                continue;
                        }

                        /* If everything matches, put it back */
                        if (!strcmp(xprt->xpt_class->xcl_name, xcl_name) &&
                            rpc_cmp_addr_port(sa, (struct sockaddr *)&xprt->xpt_local)) {
                                list_move(&xprt->xpt_list, &serv->sv_permsocks);
                                break;
                        }
                }
        }

        /*
         * If there are listener transports remaining on the permsocks list,
         * it means we were asked to remove a listener.
         */
        if (!list_empty(&permsocks)) {
                list_splice_init(&permsocks, &serv->sv_permsocks);
                delete = true;
        }
        spin_unlock_bh(&serv->sv_lock);

        /* Do not remove listeners while there are active threads. */
        if (serv->sv_nrthreads) {
                err = -EBUSY;
                goto out_unlock_mtx;
        }

        /*
         * Since we can't delete an arbitrary llist entry, destroy the
         * remaining listeners and recreate the list.
         */
        if (delete)
                svc_xprt_destroy_all(serv, net, false);

        /* walk list of addrs again, open any that still don't exist */
        nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr,
                                 GENL_HDRLEN, rem) {
                struct nlattr *tb[NFSD_A_SOCK_MAX + 1];
                const char *xcl_name;
                struct sockaddr *sa;
                int ret;

                if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
                                     nfsd_sock_nl_policy, info->extack) < 0)
                        continue;

                if (!tb[NFSD_A_SOCK_ADDR] || !tb[NFSD_A_SOCK_TRANSPORT_NAME])
                        continue;

                if (nla_len(tb[NFSD_A_SOCK_ADDR]) < sizeof(*sa))
                        continue;

                xcl_name = nla_data(tb[NFSD_A_SOCK_TRANSPORT_NAME]);
                sa = nla_data(tb[NFSD_A_SOCK_ADDR]);

                xprt = svc_find_listener(serv, xcl_name, net, sa);
                if (xprt) {
                        if (delete)
                                WARN_ONCE(1, "Transport type=%s already exists\n",
                                          xcl_name);
                        svc_xprt_put(xprt);
                        continue;
                }

                ret = svc_xprt_create_from_sa(serv, xcl_name, net, sa, 0,
                                              current_cred());
                /* always save the latest error */
                if (ret < 0)
                        err = ret;
        }

        if (!serv->sv_nrthreads && list_empty(&nn->nfsd_serv->sv_permsocks))
                nfsd_destroy_serv(net);

out_unlock_mtx:
        mutex_unlock(&nfsd_mutex);

        return err;
}

/**
 * nfsd_nl_listener_get_doit - get the nfs running listeners
 * @skb: reply buffer
 * @info: netlink metadata and command arguments
 *
 * Return 0 on success or a negative errno.
 */
int nfsd_nl_listener_get_doit(struct sk_buff *skb, struct genl_info *info)
{
        struct svc_xprt *xprt;
        struct svc_serv *serv;
        struct nfsd_net *nn;
        void *hdr;
        int err;

        skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        hdr = genlmsg_iput(skb, info);
        if (!hdr) {
                err = -EMSGSIZE;
                goto err_free_msg;
        }

        mutex_lock(&nfsd_mutex);
        nn = net_generic(genl_info_net(info), nfsd_net_id);

        /* no nfs server? Just send empty socket list */
        if (!nn->nfsd_serv)
                goto out_unlock_mtx;

        serv = nn->nfsd_serv;
        spin_lock_bh(&serv->sv_lock);
        list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
                struct nlattr *attr;

                attr = nla_nest_start(skb, NFSD_A_SERVER_SOCK_ADDR);
                if (!attr) {
                        err = -EINVAL;
                        goto err_serv_unlock;
                }

                if (nla_put_string(skb, NFSD_A_SOCK_TRANSPORT_NAME,
                                   xprt->xpt_class->xcl_name) ||
                    nla_put(skb, NFSD_A_SOCK_ADDR,
                            sizeof(struct sockaddr_storage),
                            &xprt->xpt_local)) {
                        err = -EINVAL;
                        goto err_serv_unlock;
                }

                nla_nest_end(skb, attr);
        }
        spin_unlock_bh(&serv->sv_lock);
out_unlock_mtx:
        mutex_unlock(&nfsd_mutex);
        genlmsg_end(skb, hdr);

        return genlmsg_reply(skb, info);

err_serv_unlock:
        spin_unlock_bh(&serv->sv_lock);
        mutex_unlock(&nfsd_mutex);
err_free_msg:
        nlmsg_free(skb);

        return err;
}

/**
 * nfsd_nl_pool_mode_set_doit - set the number of running threads
 * @skb: reply buffer
 * @info: netlink metadata and command arguments
 *
 * Return 0 on success or a negative errno.
 */
int nfsd_nl_pool_mode_set_doit(struct sk_buff *skb, struct genl_info *info)
{
        const struct nlattr *attr;

        if (GENL_REQ_ATTR_CHECK(info, NFSD_A_POOL_MODE_MODE))
                return -EINVAL;

        attr = info->attrs[NFSD_A_POOL_MODE_MODE];
        return sunrpc_set_pool_mode(nla_data(attr));
}

/**
 * nfsd_nl_pool_mode_get_doit - get info about pool_mode
 * @skb: reply buffer
 * @info: netlink metadata and command arguments
 *
 * Return 0 on success or a negative errno.
 */
int nfsd_nl_pool_mode_get_doit(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = genl_info_net(info);
        char buf[16];
        void *hdr;
        int err;

        if (sunrpc_get_pool_mode(buf, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
                return -ERANGE;

        skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        err = -EMSGSIZE;
        hdr = genlmsg_iput(skb, info);
        if (!hdr)
                goto err_free_msg;

        err = nla_put_string(skb, NFSD_A_POOL_MODE_MODE, buf) |
              nla_put_u32(skb, NFSD_A_POOL_MODE_NPOOLS, nfsd_nrpools(net));
        if (err)
                goto err_free_msg;

        genlmsg_end(skb, hdr);
        return genlmsg_reply(skb, info);

err_free_msg:
        nlmsg_free(skb);
        return err;
}

/**
 * nfsd_net_init - Prepare the nfsd_net portion of a new net namespace
 * @net: a freshly-created network namespace
 *
 * This information stays around as long as the network namespace is
 * alive whether or not there is an NFSD instance running in the
 * namespace.
 *
 * Returns zero on success, or a negative errno otherwise.
 */
static __net_init int nfsd_net_init(struct net *net)
{
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
        int retval;
        int i;

        retval = nfsd_export_init(net);
        if (retval)
                goto out_export_error;
        retval = nfsd_idmap_init(net);
        if (retval)
                goto out_idmap_error;
        retval = percpu_counter_init_many(nn->counter, 0, GFP_KERNEL,
                                          NFSD_STATS_COUNTERS_NUM);
        if (retval)
                goto out_repcache_error;

        memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
        nn->nfsd_svcstats.program = &nfsd_programs[0];
        if (!nfsd_proc_stat_init(net)) {
                retval = -ENOMEM;
                goto out_proc_error;
        }

        for (i = 0; i < sizeof(nn->nfsd_versions); i++)
                nn->nfsd_versions[i] = nfsd_support_version(i);
        for (i = 0; i < sizeof(nn->nfsd4_minorversions); i++)
                nn->nfsd4_minorversions[i] = nfsd_support_version(4);
        nn->nfsd_info.mutex = &nfsd_mutex;
        nn->nfsd_serv = NULL;
        nfsd4_init_leases_net(nn);
        get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
        seqlock_init(&nn->writeverf_lock);
#if IS_ENABLED(CONFIG_NFS_LOCALIO)
        spin_lock_init(&nn->local_clients_lock);
        INIT_LIST_HEAD(&nn->local_clients);
#endif
        return 0;

out_proc_error:
        percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
out_repcache_error:
        nfsd_idmap_shutdown(net);
out_idmap_error:
        nfsd_export_shutdown(net);
out_export_error:
        return retval;
}

#if IS_ENABLED(CONFIG_NFS_LOCALIO)
/**
 * nfsd_net_pre_exit - Disconnect localio clients from net namespace
 * @net: a network namespace that is about to be destroyed
 *
 * This invalidates ->net pointers held by localio clients
 * while they can still safely access nn->counter.
 */
static __net_exit void nfsd_net_pre_exit(struct net *net)
{
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);

        nfs_localio_invalidate_clients(&nn->local_clients,
                                       &nn->local_clients_lock);
}
#endif

/**
 * nfsd_net_exit - Release the nfsd_net portion of a net namespace
 * @net: a network namespace that is about to be destroyed
 *
 */
static __net_exit void nfsd_net_exit(struct net *net)
{
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);

        nfsd_proc_stat_shutdown(net);
        percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
        nfsd_idmap_shutdown(net);
        nfsd_export_shutdown(net);
}

static struct pernet_operations nfsd_net_ops = {
        .init = nfsd_net_init,
#if IS_ENABLED(CONFIG_NFS_LOCALIO)
        .pre_exit = nfsd_net_pre_exit,
#endif
        .exit = nfsd_net_exit,
        .id   = &nfsd_net_id,
        .size = sizeof(struct nfsd_net),
};

static int __init init_nfsd(void)
{
        int retval;

        nfsd_debugfs_init();

        retval = nfsd4_init_slabs();
        if (retval)
                return retval;
        retval = nfsd4_init_pnfs();
        if (retval)
                goto out_free_slabs;
        retval = nfsd_drc_slab_create();
        if (retval)
                goto out_free_pnfs;
        nfsd_lockd_init();      /* lockd->nfsd callbacks */
        retval = nfsd_export_wq_init();
        if (retval)
                goto out_free_lockd;
        retval = register_pernet_subsys(&nfsd_net_ops);
        if (retval < 0)
                goto out_free_export_wq;
        retval = register_cld_notifier();
        if (retval)
                goto out_free_subsys;
        retval = nfsd4_create_laundry_wq();
        if (retval)
                goto out_free_cld;
        retval = register_filesystem(&nfsd_fs_type);
        if (retval)
                goto out_free_nfsd4;
        retval = genl_register_family(&nfsd_nl_family);
        if (retval)
                goto out_free_filesystem;
        retval = create_proc_exports_entry();
        if (retval)
                goto out_free_all;
        nfsd_localio_ops_init();

        return 0;
out_free_all:
        genl_unregister_family(&nfsd_nl_family);
out_free_filesystem:
        unregister_filesystem(&nfsd_fs_type);
out_free_nfsd4:
        nfsd4_destroy_laundry_wq();
out_free_cld:
        unregister_cld_notifier();
out_free_subsys:
        unregister_pernet_subsys(&nfsd_net_ops);
out_free_export_wq:
        nfsd_export_wq_shutdown();
out_free_lockd:
        nfsd_lockd_shutdown();
        nfsd_drc_slab_free();
out_free_pnfs:
        nfsd4_exit_pnfs();
out_free_slabs:
        nfsd4_free_slabs();
        nfsd_debugfs_exit();
        return retval;
}

static void __exit exit_nfsd(void)
{
        remove_proc_entry("fs/nfs/exports", NULL);
        remove_proc_entry("fs/nfs", NULL);
        genl_unregister_family(&nfsd_nl_family);
        unregister_filesystem(&nfsd_fs_type);
        nfsd4_destroy_laundry_wq();
        unregister_cld_notifier();
        unregister_pernet_subsys(&nfsd_net_ops);
        nfsd_export_wq_shutdown();
        nfsd_drc_slab_free();
        nfsd_lockd_shutdown();
        nfsd4_free_slabs();
        nfsd4_exit_pnfs();
        nfsd_debugfs_exit();
}

MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
MODULE_DESCRIPTION("In-kernel NFS server");
MODULE_LICENSE("GPL");
module_init(init_nfsd)
module_exit(exit_nfsd)