cfq-iosched: fix bug with aliased request and cooperation detection

[linux-2.6/verdex.git] / fs / nfsd / nfsctl.c

/*
 * linux/fs/nfsd/nfsctl.c
 *
 * Syscall interface to knfsd.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/module.h>

#include <linux/linkage.h>
#include <linux/time.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/fcntl.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/inet.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/ctype.h>

#include <linux/nfs.h>
#include <linux/nfsd_idmap.h>
#include <linux/lockd/bind.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/cache.h>
#include <linux/nfsd/xdr.h>
#include <linux/nfsd/syscall.h>
#include <linux/lockd/lockd.h>

#include <asm/uaccess.h>
#include <net/ipv6.h>

/*
 *      We have a single directory with 9 nodes in it.
 */
enum {
        NFSD_Root = 1,
        NFSD_Svc,
        NFSD_Add,
        NFSD_Del,
        NFSD_Export,
        NFSD_Unexport,
        NFSD_Getfd,
        NFSD_Getfs,
        NFSD_List,
        NFSD_Fh,
        NFSD_FO_UnlockIP,
        NFSD_FO_UnlockFS,
        NFSD_Threads,
        NFSD_Pool_Threads,
        NFSD_Pool_Stats,
        NFSD_Versions,
        NFSD_Ports,
        NFSD_MaxBlkSize,
        /*
         * The below MUST come last.  Otherwise we leave a hole in nfsd_files[]
         * with !CONFIG_NFSD_V4 and simple_fill_super() goes oops
         */
#ifdef CONFIG_NFSD_V4
        NFSD_Leasetime,
        NFSD_RecoveryDir,
#endif
};

/*
 * write() for these nodes.
 */
static ssize_t write_svc(struct file *file, char *buf, size_t size);
static ssize_t write_add(struct file *file, char *buf, size_t size);
static ssize_t write_del(struct file *file, char *buf, size_t size);
static ssize_t write_export(struct file *file, char *buf, size_t size);
static ssize_t write_unexport(struct file *file, char *buf, size_t size);
static ssize_t write_getfd(struct file *file, char *buf, size_t size);
static ssize_t write_getfs(struct file *file, char *buf, size_t size);
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_recoverydir(struct file *file, char *buf, size_t size);
#endif

static ssize_t (*write_op[])(struct file *, char *, size_t) = {
        [NFSD_Svc] = write_svc,
        [NFSD_Add] = write_add,
        [NFSD_Del] = write_del,
        [NFSD_Export] = write_export,
        [NFSD_Unexport] = write_unexport,
        [NFSD_Getfd] = write_getfd,
        [NFSD_Getfs] = write_getfs,
        [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_RecoveryDir] = write_recoverydir,
#endif
};

static ssize_t nfsctl_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
{
        ino_t ino =  file->f_path.dentry->d_inode->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) {
                simple_transaction_set(file, rv);
                rv = size;
        }
        return rv;
}

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,
};

static int exports_open(struct inode *inode, struct file *file)
{
        return seq_open(file, &nfs_exports_op);
}

static const struct file_operations exports_operations = {
        .open           = exports_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
        .owner          = THIS_MODULE,
};

extern int nfsd_pool_stats_open(struct inode *inode, struct file *file);

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

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

/**
 * write_svc - Start kernel's NFSD server
 *
 * Deprecated.  /proc/fs/nfsd/threads is preferred.
 * Function remains to support old versions of nfs-utils.
 *
 * Input:
 *                      buf:    struct nfsctl_svc
 *                              svc_port:       port number of this
 *                                              server's listener
 *                              svc_nthreads:   number of threads to start
 *                      size:   size in bytes of passed in nfsctl_svc
 * Output:
 *      On success:     returns zero
 *      On error:       return code is negative errno value
 */
static ssize_t write_svc(struct file *file, char *buf, size_t size)
{
        struct nfsctl_svc *data;
        if (size < sizeof(*data))
                return -EINVAL;
        data = (struct nfsctl_svc*) buf;
        return nfsd_svc(data->svc_port, data->svc_nthreads);
}

/**
 * write_add - Add or modify client entry in auth unix cache
 *
 * Deprecated.  /proc/net/rpc/auth.unix.ip is preferred.
 * Function remains to support old versions of nfs-utils.
 *
 * Input:
 *                      buf:    struct nfsctl_client
 *                              cl_ident:       '\0'-terminated C string
 *                                              containing domain name
 *                                              of client
 *                              cl_naddr:       no. of items in cl_addrlist
 *                              cl_addrlist:    array of client addresses
 *                              cl_fhkeytype:   ignored
 *                              cl_fhkeylen:    ignored
 *                              cl_fhkey:       ignored
 *                      size:   size in bytes of passed in nfsctl_client
 * Output:
 *      On success:     returns zero
 *      On error:       return code is negative errno value
 *
 * Note: Only AF_INET client addresses are passed in, since
 * nfsctl_client.cl_addrlist contains only in_addr fields for addresses.
 */
static ssize_t write_add(struct file *file, char *buf, size_t size)
{
        struct nfsctl_client *data;
        if (size < sizeof(*data))
                return -EINVAL;
        data = (struct nfsctl_client *)buf;
        return exp_addclient(data);
}

/**
 * write_del - Remove client from auth unix cache
 *
 * Deprecated.  /proc/net/rpc/auth.unix.ip is preferred.
 * Function remains to support old versions of nfs-utils.
 *
 * Input:
 *                      buf:    struct nfsctl_client
 *                              cl_ident:       '\0'-terminated C string
 *                                              containing domain name
 *                                              of client
 *                              cl_naddr:       ignored
 *                              cl_addrlist:    ignored
 *                              cl_fhkeytype:   ignored
 *                              cl_fhkeylen:    ignored
 *                              cl_fhkey:       ignored
 *                      size:   size in bytes of passed in nfsctl_client
 * Output:
 *      On success:     returns zero
 *      On error:       return code is negative errno value
 *
 * Note: Only AF_INET client addresses are passed in, since
 * nfsctl_client.cl_addrlist contains only in_addr fields for addresses.
 */
static ssize_t write_del(struct file *file, char *buf, size_t size)
{
        struct nfsctl_client *data;
        if (size < sizeof(*data))
                return -EINVAL;
        data = (struct nfsctl_client *)buf;
        return exp_delclient(data);
}

/**
 * write_export - Export part or all of a local file system
 *
 * Deprecated.  /proc/net/rpc/{nfsd.export,nfsd.fh} are preferred.
 * Function remains to support old versions of nfs-utils.
 *
 * Input:
 *                      buf:    struct nfsctl_export
 *                              ex_client:      '\0'-terminated C string
 *                                              containing domain name
 *                                              of client allowed to access
 *                                              this export
 *                              ex_path:        '\0'-terminated C string
 *                                              containing pathname of
 *                                              directory in local file system
 *                              ex_dev:         fsid to use for this export
 *                              ex_ino:         ignored
 *                              ex_flags:       export flags for this export
 *                              ex_anon_uid:    UID to use for anonymous
 *                                              requests
 *                              ex_anon_gid:    GID to use for anonymous
 *                                              requests
 *                      size:   size in bytes of passed in nfsctl_export
 * Output:
 *      On success:     returns zero
 *      On error:       return code is negative errno value
 */
static ssize_t write_export(struct file *file, char *buf, size_t size)
{
        struct nfsctl_export *data;
        if (size < sizeof(*data))
                return -EINVAL;
        data = (struct nfsctl_export*)buf;
        return exp_export(data);
}

/**
 * write_unexport - Unexport a previously exported file system
 *
 * Deprecated.  /proc/net/rpc/{nfsd.export,nfsd.fh} are preferred.
 * Function remains to support old versions of nfs-utils.
 *
 * Input:
 *                      buf:    struct nfsctl_export
 *                              ex_client:      '\0'-terminated C string
 *                                              containing domain name
 *                                              of client no longer allowed
 *                                              to access this export
 *                              ex_path:        '\0'-terminated C string
 *                                              containing pathname of
 *                                              directory in local file system
 *                              ex_dev:         ignored
 *                              ex_ino:         ignored
 *                              ex_flags:       ignored
 *                              ex_anon_uid:    ignored
 *                              ex_anon_gid:    ignored
 *                      size:   size in bytes of passed in nfsctl_export
 * Output:
 *      On success:     returns zero
 *      On error:       return code is negative errno value
 */
static ssize_t write_unexport(struct file *file, char *buf, size_t size)
{
        struct nfsctl_export *data;

        if (size < sizeof(*data))
                return -EINVAL;
        data = (struct nfsctl_export*)buf;
        return exp_unexport(data);
}

/**
 * write_getfs - Get a variable-length NFS file handle by path
 *
 * Deprecated.  /proc/fs/nfsd/filehandle is preferred.
 * Function remains to support old versions of nfs-utils.
 *
 * Input:
 *                      buf:    struct nfsctl_fsparm
 *                              gd_addr:        socket address of client
 *                              gd_path:        '\0'-terminated C string
 *                                              containing pathname of
 *                                              directory in local file system
 *                              gd_maxlen:      maximum size of returned file
 *                                              handle
 *                      size:   size in bytes of passed in nfsctl_fsparm
 * Output:
 *      On success:     passed-in buffer filled with a knfsd_fh structure
 *                      (a variable-length raw NFS file handle);
 *                      return code is the size in bytes of the file handle
 *      On error:       return code is negative errno value
 *
 * Note: Only AF_INET client addresses are passed in, since gd_addr
 * is the same size as a struct sockaddr_in.
 */
static ssize_t write_getfs(struct file *file, char *buf, size_t size)
{
        struct nfsctl_fsparm *data;
        struct sockaddr_in *sin;
        struct auth_domain *clp;
        int err = 0;
        struct knfsd_fh *res;
        struct in6_addr in6;

        if (size < sizeof(*data))
                return -EINVAL;
        data = (struct nfsctl_fsparm*)buf;
        err = -EPROTONOSUPPORT;
        if (data->gd_addr.sa_family != AF_INET)
                goto out;
        sin = (struct sockaddr_in *)&data->gd_addr;
        if (data->gd_maxlen > NFS3_FHSIZE)
                data->gd_maxlen = NFS3_FHSIZE;

        res = (struct knfsd_fh*)buf;

        exp_readlock();

        ipv6_addr_set_v4mapped(sin->sin_addr.s_addr, &in6);

        clp = auth_unix_lookup(&in6);
        if (!clp)
                err = -EPERM;
        else {
                err = exp_rootfh(clp, data->gd_path, res, data->gd_maxlen);
                auth_domain_put(clp);
        }
        exp_readunlock();
        if (err == 0)
                err = res->fh_size + offsetof(struct knfsd_fh, fh_base);
 out:
        return err;
}

/**
 * write_getfd - Get a fixed-length NFS file handle by path (used by mountd)
 *
 * Deprecated.  /proc/fs/nfsd/filehandle is preferred.
 * Function remains to support old versions of nfs-utils.
 *
 * Input:
 *                      buf:    struct nfsctl_fdparm
 *                              gd_addr:        socket address of client
 *                              gd_path:        '\0'-terminated C string
 *                                              containing pathname of
 *                                              directory in local file system
 *                              gd_version:     fdparm structure version
 *                      size:   size in bytes of passed in nfsctl_fdparm
 * Output:
 *      On success:     passed-in buffer filled with nfsctl_res
 *                      (a fixed-length raw NFS file handle);
 *                      return code is the size in bytes of the file handle
 *      On error:       return code is negative errno value
 *
 * Note: Only AF_INET client addresses are passed in, since gd_addr
 * is the same size as a struct sockaddr_in.
 */
static ssize_t write_getfd(struct file *file, char *buf, size_t size)
{
        struct nfsctl_fdparm *data;
        struct sockaddr_in *sin;
        struct auth_domain *clp;
        int err = 0;
        struct knfsd_fh fh;
        char *res;
        struct in6_addr in6;

        if (size < sizeof(*data))
                return -EINVAL;
        data = (struct nfsctl_fdparm*)buf;
        err = -EPROTONOSUPPORT;
        if (data->gd_addr.sa_family != AF_INET)
                goto out;
        err = -EINVAL;
        if (data->gd_version < 2 || data->gd_version > NFSSVC_MAXVERS)
                goto out;

        res = buf;
        sin = (struct sockaddr_in *)&data->gd_addr;
        exp_readlock();

        ipv6_addr_set_v4mapped(sin->sin_addr.s_addr, &in6);

        clp = auth_unix_lookup(&in6);
        if (!clp)
                err = -EPERM;
        else {
                err = exp_rootfh(clp, data->gd_path, &fh, NFS_FHSIZE);
                auth_domain_put(clp);
        }
        exp_readunlock();

        if (err == 0) {
                memset(res,0, NFS_FHSIZE);
                memcpy(res, &fh.fh_base, fh.fh_size);
                err = NFS_FHSIZE;
        }
 out:
        return err;
}

/**
 * write_unlock_ip - Release all locks used by a client
 *
 * Experimental.
 *
 * Input:
 *                      buf:    '\n'-terminated C string containing a
 *                              presentation format IPv4 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
 *
 * Note: Only AF_INET client addresses are passed in
 */
static ssize_t write_unlock_ip(struct file *file, char *buf, size_t size)
{
        struct sockaddr_in sin = {
                .sin_family     = AF_INET,
        };
        int b1, b2, b3, b4;
        char c;
        char *fo_path;

        /* 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;

        /* get ipv4 address */
        if (sscanf(fo_path, "%u.%u.%u.%u%c", &b1, &b2, &b3, &b4, &c) != 4)
                return -EINVAL;
        if (b1 > 255 || b2 > 255 || b3 > 255 || b4 > 255)
                return -EINVAL;
        sin.sin_addr.s_addr = htonl((b1 << 24) | (b2 << 16) | (b3 << 8) | b4);

        return nlmsvc_unlock_all_by_ip((struct sockaddr *)&sin);
}

/**
 * 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;

        /* 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;

        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?
         */
        error = nlmsvc_unlock_all_by_sb(path.mnt->mnt_sb);

        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 uninitialized_var(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;
        if (maxsize > NFS3_FHSIZE)
                maxsize = NFS3_FHSIZE;

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

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

        len = exp_rootfh(dom, path, &fh,  maxsize);
        auth_domain_put(dom);
        if (len)
                return len;
        
        mesg = buf;
        len = SIMPLE_TRANSACTION_LIMIT;
        qword_addhex(&mesg, &len, (char*)&fh.fh_base, fh.fh_size);
        mesg[-1] = '\n';
        return mesg - buf;      
}

/**
 * write_threads - Start NFSD, or report the current number of running threads
 *
 * Input:
 *                      buf:            ignored
 *                      size:           zero
 * Output:
 *      On success:     passed-in buffer filled with '\n'-terminated C
 *                      string numeric value representing the number of
 *                      running 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 number of
 *                      running 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;
        if (size > 0) {
                int newthreads;
                rv = get_int(&mesg, &newthreads);
                if (rv)
                        return rv;
                if (newthreads < 0)
                        return -EINVAL;
                rv = nfsd_svc(NFS_PORT, newthreads);
                if (rv)
                        return rv;
        }
        sprintf(buf, "%d\n", nfsd_nrthreads());
        return strlen(buf);
}

/**
 * write_pool_threads - Set or report the current 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
 *                      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;

        mutex_lock(&nfsd_mutex);
        npools = nfsd_nrpools();
        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 = kcalloc(npools, sizeof(int), GFP_KERNEL);
        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;
                }
                rv = nfsd_set_nrthreads(i, nthreads);
                if (rv)
                        goto out_free;
        }

        rv = nfsd_get_nrthreads(npools, nthreads);
        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;
        }

        mutex_unlock(&nfsd_mutex);
        return (mesg-buf);

out_free:
        kfree(nthreads);
        mutex_unlock(&nfsd_mutex);
        return rv;
}

static ssize_t __write_versions(struct file *file, char *buf, size_t size)
{
        char *mesg = buf;
        char *vers, *minorp, sign;
        int len, num;
        unsigned minor;
        ssize_t tlen = 0;
        char *sep;

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

                vers = mesg;
                len = qword_get(&mesg, vers, size);
                if (len <= 0) return -EINVAL;
                do {
                        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;
                                minor = simple_strtoul(minorp+1, NULL, 0);
                                if (minor == 0)
                                        return -EINVAL;
                                if (nfsd_minorversion(minor, sign == '-' ?
                                                     NFSD_CLEAR : NFSD_SET) < 0)
                                        return -EINVAL;
                                goto next;
                        }
                        switch(num) {
                        case 2:
                        case 3:
                        case 4:
                                nfsd_vers(num, sign == '-' ? NFSD_CLEAR : NFSD_SET);
                                break;
                        default:
                                return -EINVAL;
                        }
                next:
                        vers += len + 1;
                        tlen += len;
                } 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();
        }
        /* Now write current state into reply buffer */
        len = 0;
        sep = "";
        for (num=2 ; num <= 4 ; num++)
                if (nfsd_vers(num, NFSD_AVAIL)) {
                        len += sprintf(buf+len, "%s%c%d", sep,
                                       nfsd_vers(num, NFSD_TEST)?'+':'-',
                                       num);
                        sep = " ";
                }
        if (nfsd_vers(4, NFSD_AVAIL))
                for (minor = 1; minor <= NFSD_SUPPORTED_MINOR_VERSION; minor++)
                        len += sprintf(buf+len, " %c4.%u",
                                        (nfsd_vers(4, NFSD_TEST) &&
                                         nfsd_minorversion(minor, NFSD_TEST)) ?
                                                '+' : '-',
                                        minor);
        len += sprintf(buf+len, "\n");
        return 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;
}

static ssize_t __write_ports(struct file *file, char *buf, size_t size)
{
        if (size == 0) {
                int len = 0;

                if (nfsd_serv)
                        len = svc_xprt_names(nfsd_serv, buf, 0);
                return len;
        }
        /* Either a single 'fd' number is written, in which
         * case it must be for a socket of a supported family/protocol,
         * and we use it as an nfsd socket, or
         * A '-' followed by the 'name' of a socket in which case
         * we close the socket.
         */
        if (isdigit(buf[0])) {
                char *mesg = buf;
                int fd;
                int err;
                err = get_int(&mesg, &fd);
                if (err)
                        return -EINVAL;
                if (fd < 0)
                        return -EINVAL;
                err = nfsd_create_serv();
                if (!err) {
                        err = svc_addsock(nfsd_serv, fd, buf);
                        if (err >= 0) {
                                err = lockd_up();
                                if (err < 0)
                                        svc_sock_names(buf+strlen(buf)+1, nfsd_serv, buf);
                        }
                        /* Decrease the count, but don't shutdown the
                         * the service
                         */
                        nfsd_serv->sv_nrthreads--;
                }
                return err < 0 ? err : 0;
        }
        if (buf[0] == '-' && isdigit(buf[1])) {
                char *toclose = kstrdup(buf+1, GFP_KERNEL);
                int len = 0;
                if (!toclose)
                        return -ENOMEM;
                if (nfsd_serv)
                        len = svc_sock_names(buf, nfsd_serv, toclose);
                if (len >= 0)
                        lockd_down();
                kfree(toclose);
                return len;
        }
        /*
         * Add a transport listener by writing it's transport name
         */
        if (isalpha(buf[0])) {
                int err;
                char transport[16];
                int port;
                if (sscanf(buf, "%15s %4d", transport, &port) == 2) {
                        if (port < 1 || port > 65535)
                                return -EINVAL;
                        err = nfsd_create_serv();
                        if (!err) {
                                err = svc_create_xprt(nfsd_serv,
                                                      transport, PF_INET, port,
                                                      SVC_SOCK_ANONYMOUS);
                                if (err == -ENOENT)
                                        /* Give a reasonable perror msg for
                                         * bad transport string */
                                        err = -EPROTONOSUPPORT;
                        }
                        return err < 0 ? err : 0;
                }
        }
        /*
         * Remove a transport by writing it's transport name and port number
         */
        if (buf[0] == '-' && isalpha(buf[1])) {
                struct svc_xprt *xprt;
                int err = -EINVAL;
                char transport[16];
                int port;
                if (sscanf(&buf[1], "%15s %4d", transport, &port) == 2) {
                        if (port < 1 || port > 65535)
                                return -EINVAL;
                        if (nfsd_serv) {
                                xprt = svc_find_xprt(nfsd_serv, transport,
                                                     AF_UNSPEC, port);
                                if (xprt) {
                                        svc_close_xprt(xprt);
                                        svc_xprt_put(xprt);
                                        err = 0;
                                } else
                                        err = -ENOTCONN;
                        }
                        return err < 0 ? err : 0;
                }
        }
        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
 *                      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 "-" followed
 *                                      by an integer value representing a
 *                                      previously passed in socket file
 *                                      descriptor
 *                      size:           non-zero length of C string in @buf
 * Output:
 *      On success:     NFS service no longer listens on that socket;
 *                      passed-in buffer filled with a '\n'-terminated C
 *                      string containing a unique 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
 *
 * OR
 *
 * Input:
 *                      buf:            C string containing a "-" followed
 *                                      by 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 no longer listens
 *                      on that transport
 *      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);
        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;
        if (size > 0) {
                int bsize;
                int rv = get_int(&mesg, &bsize);
                if (rv)
                        return rv;
                /* force bsize into allowed range and
                 * required alignment.
                 */
                if (bsize < 1024)
                        bsize = 1024;
                if (bsize > NFSSVC_MAXBLKSIZE)
                        bsize = NFSSVC_MAXBLKSIZE;
                bsize &= ~(1024-1);
                mutex_lock(&nfsd_mutex);
                if (nfsd_serv && nfsd_serv->sv_nrthreads) {
                        mutex_unlock(&nfsd_mutex);
                        return -EBUSY;
                }
                nfsd_max_blksize = bsize;
                mutex_unlock(&nfsd_mutex);
        }
        return sprintf(buf, "%d\n", nfsd_max_blksize);
}

#ifdef CONFIG_NFSD_V4
extern time_t nfs4_leasetime(void);

static ssize_t __write_leasetime(struct file *file, char *buf, size_t size)
{
        /* if size > 10 seconds, call
         * nfs4_reset_lease() then write out the new lease (seconds) as reply
         */
        char *mesg = buf;
        int rv, lease;

        if (size > 0) {
                if (nfsd_serv)
                        return -EBUSY;
                rv = get_int(&mesg, &lease);
                if (rv)
                        return rv;
                if (lease < 10 || lease > 3600)
                        return -EINVAL;
                nfs4_reset_lease(lease);
        }
        sprintf(buf, "%ld\n", nfs4_lease_time());
        return strlen(buf);
}

/**
 * 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)
{
        ssize_t rv;

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

extern char *nfs4_recoverydir(void);

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

        if (size > 0) {
                if (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;

                status = nfs4_reset_recoverydir(recdir);
        }
        sprintf(buf, "%s\n", nfs4_recoverydir());
        return strlen(buf);
}

/**
 * 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;

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

#endif

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

static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
{
        static struct tree_descr nfsd_files[] = {
                [NFSD_Svc] = {".svc", &transaction_ops, S_IWUSR},
                [NFSD_Add] = {".add", &transaction_ops, S_IWUSR},
                [NFSD_Del] = {".del", &transaction_ops, S_IWUSR},
                [NFSD_Export] = {".export", &transaction_ops, S_IWUSR},
                [NFSD_Unexport] = {".unexport", &transaction_ops, S_IWUSR},
                [NFSD_Getfd] = {".getfd", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_Getfs] = {".getfs", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_List] = {"exports", &exports_operations, 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_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},
#ifdef CONFIG_NFSD_V4
                [NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
                [NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},
#endif
                /* last one */ {""}
        };
        return simple_fill_super(sb, 0x6e667364, nfsd_files);
}

static int nfsd_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
        return get_sb_single(fs_type, flags, data, nfsd_fill_super, mnt);
}

static struct file_system_type nfsd_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "nfsd",
        .get_sb         = nfsd_get_sb,
        .kill_sb        = kill_litter_super,
};

#ifdef CONFIG_PROC_FS
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_operations);
        if (!entry)
                return -ENOMEM;
        return 0;
}
#else /* CONFIG_PROC_FS */
static int create_proc_exports_entry(void)
{
        return 0;
}
#endif

static int __init init_nfsd(void)
{
        int retval;
        printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).\n");

        retval = nfs4_state_init(); /* nfs4 locking state */
        if (retval)
                return retval;
        nfsd_stat_init();       /* Statistics */
        retval = nfsd_reply_cache_init();
        if (retval)
                goto out_free_stat;
        retval = nfsd_export_init();
        if (retval)
                goto out_free_cache;
        nfsd_lockd_init();      /* lockd->nfsd callbacks */
        retval = nfsd_idmap_init();
        if (retval)
                goto out_free_lockd;
        retval = create_proc_exports_entry();
        if (retval)
                goto out_free_idmap;
        retval = register_filesystem(&nfsd_fs_type);
        if (retval)
                goto out_free_all;
        return 0;
out_free_all:
        remove_proc_entry("fs/nfs/exports", NULL);
        remove_proc_entry("fs/nfs", NULL);
out_free_idmap:
        nfsd_idmap_shutdown();
out_free_lockd:
        nfsd_lockd_shutdown();
        nfsd_export_shutdown();
out_free_cache:
        nfsd_reply_cache_shutdown();
out_free_stat:
        nfsd_stat_shutdown();
        nfsd4_free_slabs();
        return retval;
}

static void __exit exit_nfsd(void)
{
        nfsd_export_shutdown();
        nfsd_reply_cache_shutdown();
        remove_proc_entry("fs/nfs/exports", NULL);
        remove_proc_entry("fs/nfs", NULL);
        nfsd_stat_shutdown();
        nfsd_lockd_shutdown();
        nfsd_idmap_shutdown();
        nfsd4_free_slabs();
        unregister_filesystem(&nfsd_fs_type);
}

MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
MODULE_LICENSE("GPL");
module_init(init_nfsd)
module_exit(exit_nfsd)