[PATCH] knfsd: nfsd4: remove nfs4_reclaim_init

[safe/jmp/linux-2.6] / fs / nfsd / nfs4state.c

/*
*  linux/fs/nfsd/nfs4state.c
*
*  Copyright (c) 2001 The Regents of the University of Michigan.
*  All rights reserved.
*
*  Kendrick Smith <kmsmith@umich.edu>
*  Andy Adamson <kandros@umich.edu>
*
*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions
*  are met:
*
*  1. Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*  2. Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in the
*     documentation and/or other materials provided with the distribution.
*  3. Neither the name of the University nor the names of its
*     contributors may be used to endorse or promote products derived
*     from this software without specific prior written permission.
*
*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
*  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
*  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
*  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
*  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
*  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
*  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
*  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
*  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/

#include <linux/param.h>
#include <linux/major.h>
#include <linux/slab.h>

#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/cache.h>
#include <linux/mount.h>
#include <linux/workqueue.h>
#include <linux/smp_lock.h>
#include <linux/kthread.h>
#include <linux/nfs4.h>
#include <linux/nfsd/state.h>
#include <linux/nfsd/xdr4.h>

#define NFSDDBG_FACILITY                NFSDDBG_PROC

/* Globals */
static time_t lease_time = 90;     /* default lease time */
static time_t user_lease_time = 90;
time_t boot_time;
static time_t grace_end = 0;
static u32 current_clientid = 1;
static u32 current_ownerid = 1;
static u32 current_fileid = 1;
static u32 current_delegid = 1;
static u32 nfs4_init;
stateid_t zerostateid;             /* bits all 0 */
stateid_t onestateid;              /* bits all 1 */

/* forward declarations */
struct nfs4_stateid * find_stateid(stateid_t *stid, int flags);
static struct nfs4_delegation * find_delegation_stateid(struct inode *ino, stateid_t *stid);
static void release_stateid_lockowners(struct nfs4_stateid *open_stp);

/* Locking:
 *
 * client_sema: 
 *      protects clientid_hashtbl[], clientstr_hashtbl[],
 *      unconfstr_hashtbl[], uncofid_hashtbl[].
 */
static DECLARE_MUTEX(client_sema);

kmem_cache_t *stateowner_slab = NULL;
kmem_cache_t *file_slab = NULL;
kmem_cache_t *stateid_slab = NULL;
kmem_cache_t *deleg_slab = NULL;

void
nfs4_lock_state(void)
{
        down(&client_sema);
}

void
nfs4_unlock_state(void)
{
        up(&client_sema);
}

static inline u32
opaque_hashval(const void *ptr, int nbytes)
{
        unsigned char *cptr = (unsigned char *) ptr;

        u32 x = 0;
        while (nbytes--) {
                x *= 37;
                x += *cptr++;
        }
        return x;
}

/* forward declarations */
static void release_stateowner(struct nfs4_stateowner *sop);
static void release_stateid(struct nfs4_stateid *stp, int flags);

/*
 * Delegation state
 */

/* recall_lock protects the del_recall_lru */
spinlock_t recall_lock = SPIN_LOCK_UNLOCKED;
static struct list_head del_recall_lru;

static void
free_nfs4_file(struct kref *kref)
{
        struct nfs4_file *fp = container_of(kref, struct nfs4_file, fi_ref);
        list_del(&fp->fi_hash);
        iput(fp->fi_inode);
        kmem_cache_free(file_slab, fp);
}

static inline void
put_nfs4_file(struct nfs4_file *fi)
{
        kref_put(&fi->fi_ref, free_nfs4_file);
}

static inline void
get_nfs4_file(struct nfs4_file *fi)
{
        kref_get(&fi->fi_ref);
}

static struct nfs4_delegation *
alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_fh *current_fh, u32 type)
{
        struct nfs4_delegation *dp;
        struct nfs4_file *fp = stp->st_file;
        struct nfs4_callback *cb = &stp->st_stateowner->so_client->cl_callback;

        dprintk("NFSD alloc_init_deleg\n");
        dp = kmem_cache_alloc(deleg_slab, GFP_KERNEL);
        if (dp == NULL)
                return dp;
        INIT_LIST_HEAD(&dp->dl_del_perfile);
        INIT_LIST_HEAD(&dp->dl_del_perclnt);
        INIT_LIST_HEAD(&dp->dl_recall_lru);
        dp->dl_client = clp;
        get_nfs4_file(fp);
        dp->dl_file = fp;
        dp->dl_flock = NULL;
        get_file(stp->st_vfs_file);
        dp->dl_vfs_file = stp->st_vfs_file;
        dp->dl_type = type;
        dp->dl_recall.cbr_dp = NULL;
        dp->dl_recall.cbr_ident = cb->cb_ident;
        dp->dl_recall.cbr_trunc = 0;
        dp->dl_stateid.si_boot = boot_time;
        dp->dl_stateid.si_stateownerid = current_delegid++;
        dp->dl_stateid.si_fileid = 0;
        dp->dl_stateid.si_generation = 0;
        dp->dl_fhlen = current_fh->fh_handle.fh_size;
        memcpy(dp->dl_fhval, &current_fh->fh_handle.fh_base,
                        current_fh->fh_handle.fh_size);
        dp->dl_time = 0;
        atomic_set(&dp->dl_count, 1);
        list_add(&dp->dl_del_perfile, &fp->fi_delegations);
        list_add(&dp->dl_del_perclnt, &clp->cl_del_perclnt);
        return dp;
}

void
nfs4_put_delegation(struct nfs4_delegation *dp)
{
        if (atomic_dec_and_test(&dp->dl_count)) {
                dprintk("NFSD: freeing dp %p\n",dp);
                put_nfs4_file(dp->dl_file);
                kmem_cache_free(deleg_slab, dp);
        }
}

/* Remove the associated file_lock first, then remove the delegation.
 * lease_modify() is called to remove the FS_LEASE file_lock from
 * the i_flock list, eventually calling nfsd's lock_manager
 * fl_release_callback.
 */
static void
nfs4_close_delegation(struct nfs4_delegation *dp)
{
        struct file *filp = dp->dl_vfs_file;

        dprintk("NFSD: close_delegation dp %p\n",dp);
        dp->dl_vfs_file = NULL;
        /* The following nfsd_close may not actually close the file,
         * but we want to remove the lease in any case. */
        if (dp->dl_flock)
                setlease(filp, F_UNLCK, &dp->dl_flock);
        nfsd_close(filp);
}

/* Called under the state lock. */
static void
unhash_delegation(struct nfs4_delegation *dp)
{
        list_del_init(&dp->dl_del_perfile);
        list_del_init(&dp->dl_del_perclnt);
        spin_lock(&recall_lock);
        list_del_init(&dp->dl_recall_lru);
        spin_unlock(&recall_lock);
        nfs4_close_delegation(dp);
        nfs4_put_delegation(dp);
}

/* 
 * SETCLIENTID state 
 */

/* Hash tables for nfs4_clientid state */
#define CLIENT_HASH_BITS                 4
#define CLIENT_HASH_SIZE                (1 << CLIENT_HASH_BITS)
#define CLIENT_HASH_MASK                (CLIENT_HASH_SIZE - 1)

#define clientid_hashval(id) \
        ((id) & CLIENT_HASH_MASK)
#define clientstr_hashval(name, namelen) \
        (opaque_hashval((name), (namelen)) & CLIENT_HASH_MASK)
/*
 * reclaim_str_hashtbl[] holds known client info from previous reset/reboot
 * used in reboot/reset lease grace period processing
 *
 * conf_id_hashtbl[], and conf_str_hashtbl[] hold confirmed
 * setclientid_confirmed info. 
 *
 * unconf_str_hastbl[] and unconf_id_hashtbl[] hold unconfirmed 
 * setclientid info.
 *
 * client_lru holds client queue ordered by nfs4_client.cl_time
 * for lease renewal.
 *
 * close_lru holds (open) stateowner queue ordered by nfs4_stateowner.so_time
 * for last close replay.
 */
static struct list_head reclaim_str_hashtbl[CLIENT_HASH_SIZE];
static int reclaim_str_hashtbl_size = 0;
static struct list_head conf_id_hashtbl[CLIENT_HASH_SIZE];
static struct list_head conf_str_hashtbl[CLIENT_HASH_SIZE];
static struct list_head unconf_str_hashtbl[CLIENT_HASH_SIZE];
static struct list_head unconf_id_hashtbl[CLIENT_HASH_SIZE];
static struct list_head client_lru;
static struct list_head close_lru;

static inline void
renew_client(struct nfs4_client *clp)
{
        /*
        * Move client to the end to the LRU list.
        */
        dprintk("renewing client (clientid %08x/%08x)\n", 
                        clp->cl_clientid.cl_boot, 
                        clp->cl_clientid.cl_id);
        list_move_tail(&clp->cl_lru, &client_lru);
        clp->cl_time = get_seconds();
}

/* SETCLIENTID and SETCLIENTID_CONFIRM Helper functions */
static int
STALE_CLIENTID(clientid_t *clid)
{
        if (clid->cl_boot == boot_time)
                return 0;
        dprintk("NFSD stale clientid (%08x/%08x)\n", 
                        clid->cl_boot, clid->cl_id);
        return 1;
}

/* 
 * XXX Should we use a slab cache ?
 * This type of memory management is somewhat inefficient, but we use it
 * anyway since SETCLIENTID is not a common operation.
 */
static inline struct nfs4_client *
alloc_client(struct xdr_netobj name)
{
        struct nfs4_client *clp;

        if ((clp = kmalloc(sizeof(struct nfs4_client), GFP_KERNEL))!= NULL) {
                memset(clp, 0, sizeof(*clp));
                if ((clp->cl_name.data = kmalloc(name.len, GFP_KERNEL)) != NULL) {
                        memcpy(clp->cl_name.data, name.data, name.len);
                        clp->cl_name.len = name.len;
                }
                else {
                        kfree(clp);
                        clp = NULL;
                }
        }
        return clp;
}

static inline void
free_client(struct nfs4_client *clp)
{
        if (clp->cl_cred.cr_group_info)
                put_group_info(clp->cl_cred.cr_group_info);
        kfree(clp->cl_name.data);
        kfree(clp);
}

void
put_nfs4_client(struct nfs4_client *clp)
{
        if (atomic_dec_and_test(&clp->cl_count))
                free_client(clp);
}

static void
expire_client(struct nfs4_client *clp)
{
        struct nfs4_stateowner *sop;
        struct nfs4_delegation *dp;
        struct nfs4_callback *cb = &clp->cl_callback;
        struct rpc_clnt *clnt = clp->cl_callback.cb_client;
        struct list_head reaplist;

        dprintk("NFSD: expire_client cl_count %d\n",
                            atomic_read(&clp->cl_count));

        /* shutdown rpc client, ending any outstanding recall rpcs */
        if (atomic_read(&cb->cb_set) == 1 && clnt) {
                rpc_shutdown_client(clnt);
                clnt = clp->cl_callback.cb_client = NULL;
        }

        INIT_LIST_HEAD(&reaplist);
        spin_lock(&recall_lock);
        while (!list_empty(&clp->cl_del_perclnt)) {
                dp = list_entry(clp->cl_del_perclnt.next, struct nfs4_delegation, dl_del_perclnt);
                dprintk("NFSD: expire client. dp %p, fp %p\n", dp,
                                dp->dl_flock);
                list_del_init(&dp->dl_del_perclnt);
                list_move(&dp->dl_recall_lru, &reaplist);
        }
        spin_unlock(&recall_lock);
        while (!list_empty(&reaplist)) {
                dp = list_entry(reaplist.next, struct nfs4_delegation, dl_recall_lru);
                list_del_init(&dp->dl_recall_lru);
                unhash_delegation(dp);
        }
        list_del(&clp->cl_idhash);
        list_del(&clp->cl_strhash);
        list_del(&clp->cl_lru);
        while (!list_empty(&clp->cl_perclient)) {
                sop = list_entry(clp->cl_perclient.next, struct nfs4_stateowner, so_perclient);
                release_stateowner(sop);
        }
        put_nfs4_client(clp);
}

static struct nfs4_client *
create_client(struct xdr_netobj name) {
        struct nfs4_client *clp;

        if (!(clp = alloc_client(name)))
                goto out;
        atomic_set(&clp->cl_count, 1);
        atomic_set(&clp->cl_callback.cb_set, 0);
        clp->cl_callback.cb_parsed = 0;
        INIT_LIST_HEAD(&clp->cl_idhash);
        INIT_LIST_HEAD(&clp->cl_strhash);
        INIT_LIST_HEAD(&clp->cl_perclient);
        INIT_LIST_HEAD(&clp->cl_del_perclnt);
        INIT_LIST_HEAD(&clp->cl_lru);
out:
        return clp;
}

static void
copy_verf(struct nfs4_client *target, nfs4_verifier *source) {
        memcpy(target->cl_verifier.data, source->data, sizeof(target->cl_verifier.data));
}

static void
copy_clid(struct nfs4_client *target, struct nfs4_client *source) {
        target->cl_clientid.cl_boot = source->cl_clientid.cl_boot; 
        target->cl_clientid.cl_id = source->cl_clientid.cl_id; 
}

static void
copy_cred(struct svc_cred *target, struct svc_cred *source) {

        target->cr_uid = source->cr_uid;
        target->cr_gid = source->cr_gid;
        target->cr_group_info = source->cr_group_info;
        get_group_info(target->cr_group_info);
}

static int
cmp_name(struct xdr_netobj *n1, struct xdr_netobj *n2) {
        if (!n1 || !n2)
                return 0;
        return((n1->len == n2->len) && !memcmp(n1->data, n2->data, n2->len));
}

static int
cmp_verf(nfs4_verifier *v1, nfs4_verifier *v2) {
        return(!memcmp(v1->data,v2->data,sizeof(v1->data)));
}

static int
cmp_clid(clientid_t * cl1, clientid_t * cl2) {
        return((cl1->cl_boot == cl2->cl_boot) &&
                (cl1->cl_id == cl2->cl_id));
}

/* XXX what about NGROUP */
static int
cmp_creds(struct svc_cred *cr1, struct svc_cred *cr2){
        return(cr1->cr_uid == cr2->cr_uid);

}

static void
gen_clid(struct nfs4_client *clp) {
        clp->cl_clientid.cl_boot = boot_time;
        clp->cl_clientid.cl_id = current_clientid++; 
}

static void
gen_confirm(struct nfs4_client *clp) {
        struct timespec         tv;
        u32 *                   p;

        tv = CURRENT_TIME;
        p = (u32 *)clp->cl_confirm.data;
        *p++ = tv.tv_sec;
        *p++ = tv.tv_nsec;
}

static int
check_name(struct xdr_netobj name) {

        if (name.len == 0) 
                return 0;
        if (name.len > NFS4_OPAQUE_LIMIT) {
                printk("NFSD: check_name: name too long(%d)!\n", name.len);
                return 0;
        }
        return 1;
}

void
add_to_unconfirmed(struct nfs4_client *clp, unsigned int strhashval)
{
        unsigned int idhashval;

        list_add(&clp->cl_strhash, &unconf_str_hashtbl[strhashval]);
        idhashval = clientid_hashval(clp->cl_clientid.cl_id);
        list_add(&clp->cl_idhash, &unconf_id_hashtbl[idhashval]);
        list_add_tail(&clp->cl_lru, &client_lru);
        clp->cl_time = get_seconds();
}

void
move_to_confirmed(struct nfs4_client *clp)
{
        unsigned int idhashval = clientid_hashval(clp->cl_clientid.cl_id);
        unsigned int strhashval;

        dprintk("NFSD: move_to_confirm nfs4_client %p\n", clp);
        list_del_init(&clp->cl_strhash);
        list_del_init(&clp->cl_idhash);
        list_add(&clp->cl_idhash, &conf_id_hashtbl[idhashval]);
        strhashval = clientstr_hashval(clp->cl_name.data, 
                        clp->cl_name.len);
        list_add(&clp->cl_strhash, &conf_str_hashtbl[strhashval]);
        renew_client(clp);
}

static struct nfs4_client *
find_confirmed_client(clientid_t *clid)
{
        struct nfs4_client *clp;
        unsigned int idhashval = clientid_hashval(clid->cl_id);

        list_for_each_entry(clp, &conf_id_hashtbl[idhashval], cl_idhash) {
                if (cmp_clid(&clp->cl_clientid, clid))
                        return clp;
        }
        return NULL;
}

static struct nfs4_client *
find_unconfirmed_client(clientid_t *clid)
{
        struct nfs4_client *clp;
        unsigned int idhashval = clientid_hashval(clid->cl_id);

        list_for_each_entry(clp, &unconf_id_hashtbl[idhashval], cl_idhash) {
                if (cmp_clid(&clp->cl_clientid, clid))
                        return clp;
        }
        return NULL;
}

/* a helper function for parse_callback */
static int
parse_octet(unsigned int *lenp, char **addrp)
{
        unsigned int len = *lenp;
        char *p = *addrp;
        int n = -1;
        char c;

        for (;;) {
                if (!len)
                        break;
                len--;
                c = *p++;
                if (c == '.')
                        break;
                if ((c < '0') || (c > '9')) {
                        n = -1;
                        break;
                }
                if (n < 0)
                        n = 0;
                n = (n * 10) + (c - '0');
                if (n > 255) {
                        n = -1;
                        break;
                }
        }
        *lenp = len;
        *addrp = p;
        return n;
}

/* parse and set the setclientid ipv4 callback address */
int
parse_ipv4(unsigned int addr_len, char *addr_val, unsigned int *cbaddrp, unsigned short *cbportp)
{
        int temp = 0;
        u32 cbaddr = 0;
        u16 cbport = 0;
        u32 addrlen = addr_len;
        char *addr = addr_val;
        int i, shift;

        /* ipaddress */
        shift = 24;
        for(i = 4; i > 0  ; i--) {
                if ((temp = parse_octet(&addrlen, &addr)) < 0) {
                        return 0;
                }
                cbaddr |= (temp << shift);
                if (shift > 0)
                shift -= 8;
        }
        *cbaddrp = cbaddr;

        /* port */
        shift = 8;
        for(i = 2; i > 0  ; i--) {
                if ((temp = parse_octet(&addrlen, &addr)) < 0) {
                        return 0;
                }
                cbport |= (temp << shift);
                if (shift > 0)
                        shift -= 8;
        }
        *cbportp = cbport;
        return 1;
}

void
gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se)
{
        struct nfs4_callback *cb = &clp->cl_callback;

        /* Currently, we only support tcp for the callback channel */
        if ((se->se_callback_netid_len != 3) || memcmp((char *)se->se_callback_netid_val, "tcp", 3))
                goto out_err;

        if ( !(parse_ipv4(se->se_callback_addr_len, se->se_callback_addr_val,
                         &cb->cb_addr, &cb->cb_port)))
                goto out_err;
        cb->cb_prog = se->se_callback_prog;
        cb->cb_ident = se->se_callback_ident;
        cb->cb_parsed = 1;
        return;
out_err:
        printk(KERN_INFO "NFSD: this client (clientid %08x/%08x) "
                "will not receive delegations\n",
                clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);

        cb->cb_parsed = 0;
        return;
}

/*
 * RFC 3010 has a complex implmentation description of processing a 
 * SETCLIENTID request consisting of 5 bullets, labeled as 
 * CASE0 - CASE4 below.
 *
 * NOTES:
 *      callback information will be processed in a future patch
 *
 *      an unconfirmed record is added when:
 *      NORMAL (part of CASE 4): there is no confirmed nor unconfirmed record.
 *      CASE 1: confirmed record found with matching name, principal,
 *              verifier, and clientid.
 *      CASE 2: confirmed record found with matching name, principal,
 *              and there is no unconfirmed record with matching
 *              name and principal
 *
 *      an unconfirmed record is replaced when:
 *      CASE 3: confirmed record found with matching name, principal,
 *              and an unconfirmed record is found with matching 
 *              name, principal, and with clientid and
 *              confirm that does not match the confirmed record.
 *      CASE 4: there is no confirmed record with matching name and 
 *              principal. there is an unconfirmed record with 
 *              matching name, principal.
 *
 *      an unconfirmed record is deleted when:
 *      CASE 1: an unconfirmed record that matches input name, verifier,
 *              and confirmed clientid.
 *      CASE 4: any unconfirmed records with matching name and principal
 *              that exist after an unconfirmed record has been replaced
 *              as described above.
 *
 */
int
nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_setclientid *setclid)
{
        u32                     ip_addr = rqstp->rq_addr.sin_addr.s_addr;
        struct xdr_netobj       clname = { 
                .len = setclid->se_namelen,
                .data = setclid->se_name,
        };
        nfs4_verifier           clverifier = setclid->se_verf;
        unsigned int            strhashval;
        struct nfs4_client *    conf, * unconf, * new, * clp;
        int                     status;
        
        status = nfserr_inval;
        if (!check_name(clname))
                goto out;

        /* 
         * XXX The Duplicate Request Cache (DRC) has been checked (??)
         * We get here on a DRC miss.
         */

        strhashval = clientstr_hashval(clname.data, clname.len);

        conf = NULL;
        nfs4_lock_state();
        list_for_each_entry(clp, &conf_str_hashtbl[strhashval], cl_strhash) {
                if (!cmp_name(&clp->cl_name, &clname))
                        continue;
                /* 
                 * CASE 0:
                 * clname match, confirmed, different principal
                 * or different ip_address
                 */
                status = nfserr_clid_inuse;
                if (!cmp_creds(&clp->cl_cred,&rqstp->rq_cred)) {
                        printk("NFSD: setclientid: string in use by client"
                        "(clientid %08x/%08x)\n",
                        clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);
                        goto out;
                }
                if (clp->cl_addr != ip_addr) { 
                        printk("NFSD: setclientid: string in use by client"
                        "(clientid %08x/%08x)\n",
                        clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);
                        goto out;
                }

                /* 
                 * cl_name match from a previous SETCLIENTID operation
                 * XXX check for additional matches?
                 */
                conf = clp;
                break;
        }
        unconf = NULL;
        list_for_each_entry(clp, &unconf_str_hashtbl[strhashval], cl_strhash) {
                if (!cmp_name(&clp->cl_name, &clname))
                        continue;
                /* cl_name match from a previous SETCLIENTID operation */
                unconf = clp;
                break;
        }
        status = nfserr_resource;
        if (!conf) {
                /* 
                 * CASE 4:
                 * placed first, because it is the normal case.
                 */
                if (unconf)
                        expire_client(unconf);
                if (!(new = create_client(clname)))
                        goto out;
                copy_verf(new, &clverifier);
                new->cl_addr = ip_addr;
                copy_cred(&new->cl_cred,&rqstp->rq_cred);
                gen_clid(new);
                gen_confirm(new);
                gen_callback(new, setclid);
                add_to_unconfirmed(new, strhashval);
        } else if (cmp_verf(&conf->cl_verifier, &clverifier)) {
                /*
                 * CASE 1:
                 * cl_name match, confirmed, principal match
                 * verifier match: probable callback update
                 *
                 * remove any unconfirmed nfs4_client with 
                 * matching cl_name, cl_verifier, and cl_clientid
                 *
                 * create and insert an unconfirmed nfs4_client with same 
                 * cl_name, cl_verifier, and cl_clientid as existing 
                 * nfs4_client,  but with the new callback info and a 
                 * new cl_confirm
                 */
                if ((unconf) && 
                    cmp_verf(&unconf->cl_verifier, &conf->cl_verifier) &&
                     cmp_clid(&unconf->cl_clientid, &conf->cl_clientid)) {
                                expire_client(unconf);
                }
                if (!(new = create_client(clname)))
                        goto out;
                copy_verf(new,&conf->cl_verifier);
                new->cl_addr = ip_addr;
                copy_cred(&new->cl_cred,&rqstp->rq_cred);
                copy_clid(new, conf);
                gen_confirm(new);
                gen_callback(new, setclid);
                add_to_unconfirmed(new,strhashval);
        } else if (!unconf) {
                /*
                 * CASE 2:
                 * clname match, confirmed, principal match
                 * verfier does not match
                 * no unconfirmed. create a new unconfirmed nfs4_client
                 * using input clverifier, clname, and callback info
                 * and generate a new cl_clientid and cl_confirm.
                 */
                if (!(new = create_client(clname)))
                        goto out;
                copy_verf(new,&clverifier);
                new->cl_addr = ip_addr;
                copy_cred(&new->cl_cred,&rqstp->rq_cred);
                gen_clid(new);
                gen_confirm(new);
                gen_callback(new, setclid);
                add_to_unconfirmed(new, strhashval);
        } else if (!cmp_verf(&conf->cl_confirm, &unconf->cl_confirm)) {
                /*      
                 * CASE3:
                 * confirmed found (name, principal match)
                 * confirmed verifier does not match input clverifier
                 *
                 * unconfirmed found (name match)
                 * confirmed->cl_confirm != unconfirmed->cl_confirm
                 *
                 * remove unconfirmed.
                 *
                 * create an unconfirmed nfs4_client 
                 * with same cl_name as existing confirmed nfs4_client, 
                 * but with new callback info, new cl_clientid,
                 * new cl_verifier and a new cl_confirm
                 */
                expire_client(unconf);
                if (!(new = create_client(clname)))
                        goto out;
                copy_verf(new,&clverifier);
                new->cl_addr = ip_addr;
                copy_cred(&new->cl_cred,&rqstp->rq_cred);
                gen_clid(new);
                gen_confirm(new);
                gen_callback(new, setclid);
                add_to_unconfirmed(new, strhashval);
        } else {
                /* No cases hit !!! */
                status = nfserr_inval;
                goto out;

        }
        setclid->se_clientid.cl_boot = new->cl_clientid.cl_boot;
        setclid->se_clientid.cl_id = new->cl_clientid.cl_id;
        memcpy(setclid->se_confirm.data, new->cl_confirm.data, sizeof(setclid->se_confirm.data));
        status = nfs_ok;
out:
        nfs4_unlock_state();
        return status;
}


/*
 * RFC 3010 has a complex implmentation description of processing a 
 * SETCLIENTID_CONFIRM request consisting of 4 bullets describing
 * processing on a DRC miss, labeled as CASE1 - CASE4 below.
 *
 * NOTE: callback information will be processed here in a future patch
 */
int
nfsd4_setclientid_confirm(struct svc_rqst *rqstp, struct nfsd4_setclientid_confirm *setclientid_confirm)
{
        u32 ip_addr = rqstp->rq_addr.sin_addr.s_addr;
        struct nfs4_client *clp, *conf = NULL, *unconf = NULL;
        nfs4_verifier confirm = setclientid_confirm->sc_confirm; 
        clientid_t * clid = &setclientid_confirm->sc_clientid;
        int status;

        if (STALE_CLIENTID(clid))
                return nfserr_stale_clientid;
        /* 
         * XXX The Duplicate Request Cache (DRC) has been checked (??)
         * We get here on a DRC miss.
         */

        nfs4_lock_state();
        clp = find_confirmed_client(clid);
        if (clp) {
                status = nfserr_inval;
                /* 
                 * Found a record for this clientid. If the IP addresses
                 * don't match, return ERR_INVAL just as if the record had
                 * not been found.
                 */
                if (clp->cl_addr != ip_addr) { 
                        printk("NFSD: setclientid: string in use by client"
                        "(clientid %08x/%08x)\n",
                        clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);
                        goto out;
                }
                conf = clp;
        }
        clp = find_unconfirmed_client(clid);
        if (clp) {
                status = nfserr_inval;
                if (clp->cl_addr != ip_addr) { 
                        printk("NFSD: setclientid: string in use by client"
                        "(clientid %08x/%08x)\n",
                        clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);
                        goto out;
                }
                unconf = clp;
        }
        /* CASE 1: 
        * unconf record that matches input clientid and input confirm.
        * conf record that matches input clientid.
        * conf  and unconf records match names, verifiers 
        */
        if ((conf && unconf) && 
            (cmp_verf(&unconf->cl_confirm, &confirm)) &&
            (cmp_verf(&conf->cl_verifier, &unconf->cl_verifier)) &&
            (cmp_name(&conf->cl_name,&unconf->cl_name))  &&
            (!cmp_verf(&conf->cl_confirm, &unconf->cl_confirm))) {
                if (!cmp_creds(&conf->cl_cred, &unconf->cl_cred)) 
                        status = nfserr_clid_inuse;
                else {
                        expire_client(conf);
                        clp = unconf;
                        move_to_confirmed(unconf);
                        status = nfs_ok;
                }
                goto out;
        } 
        /* CASE 2:
         * conf record that matches input clientid.
         * if unconf record that matches input clientid, then unconf->cl_name
         * or unconf->cl_verifier don't match the conf record.
         */
        if ((conf && !unconf) || 
            ((conf && unconf) && 
             (!cmp_verf(&conf->cl_verifier, &unconf->cl_verifier) ||
              !cmp_name(&conf->cl_name, &unconf->cl_name)))) {
                if (!cmp_creds(&conf->cl_cred,&rqstp->rq_cred)) {
                        status = nfserr_clid_inuse;
                } else {
                        clp = conf;
                        status = nfs_ok;
                }
                goto out;
        }
        /* CASE 3:
         * conf record not found.
         * unconf record found. 
         * unconf->cl_confirm matches input confirm
         */ 
        if (!conf && unconf && cmp_verf(&unconf->cl_confirm, &confirm)) {
                if (!cmp_creds(&unconf->cl_cred, &rqstp->rq_cred)) {
                        status = nfserr_clid_inuse;
                } else {
                        status = nfs_ok;
                        clp = unconf;
                        move_to_confirmed(unconf);
                }
                goto out;
        }
        /* CASE 4:
         * conf record not found, or if conf, then conf->cl_confirm does not
         * match input confirm.
         * unconf record not found, or if unconf, then unconf->cl_confirm 
         * does not match input confirm.
         */
        if ((!conf || (conf && !cmp_verf(&conf->cl_confirm, &confirm))) &&
            (!unconf || (unconf && !cmp_verf(&unconf->cl_confirm, &confirm)))) {
                status = nfserr_stale_clientid;
                goto out;
        }
        /* check that we have hit one of the cases...*/
        status = nfserr_inval;
        goto out;
out:
        if (!status)
                nfsd4_probe_callback(clp);
        nfs4_unlock_state();
        return status;
}

/* 
 * Open owner state (share locks)
 */

/* hash tables for nfs4_stateowner */
#define OWNER_HASH_BITS              8
#define OWNER_HASH_SIZE             (1 << OWNER_HASH_BITS)
#define OWNER_HASH_MASK             (OWNER_HASH_SIZE - 1)

#define ownerid_hashval(id) \
        ((id) & OWNER_HASH_MASK)
#define ownerstr_hashval(clientid, ownername) \
        (((clientid) + opaque_hashval((ownername.data), (ownername.len))) & OWNER_HASH_MASK)

static struct list_head ownerid_hashtbl[OWNER_HASH_SIZE];
static struct list_head ownerstr_hashtbl[OWNER_HASH_SIZE];

/* hash table for nfs4_file */
#define FILE_HASH_BITS                   8
#define FILE_HASH_SIZE                  (1 << FILE_HASH_BITS)
#define FILE_HASH_MASK                  (FILE_HASH_SIZE - 1)
/* hash table for (open)nfs4_stateid */
#define STATEID_HASH_BITS              10
#define STATEID_HASH_SIZE              (1 << STATEID_HASH_BITS)
#define STATEID_HASH_MASK              (STATEID_HASH_SIZE - 1)

#define file_hashval(x) \
        hash_ptr(x, FILE_HASH_BITS)
#define stateid_hashval(owner_id, file_id)  \
        (((owner_id) + (file_id)) & STATEID_HASH_MASK)

static struct list_head file_hashtbl[FILE_HASH_SIZE];
static struct list_head stateid_hashtbl[STATEID_HASH_SIZE];

/* OPEN Share state helper functions */
static inline struct nfs4_file *
alloc_init_file(struct inode *ino)
{
        struct nfs4_file *fp;
        unsigned int hashval = file_hashval(ino);

        fp = kmem_cache_alloc(file_slab, GFP_KERNEL);
        if (fp) {
                kref_init(&fp->fi_ref);
                INIT_LIST_HEAD(&fp->fi_hash);
                INIT_LIST_HEAD(&fp->fi_stateids);
                INIT_LIST_HEAD(&fp->fi_delegations);
                list_add(&fp->fi_hash, &file_hashtbl[hashval]);
                fp->fi_inode = igrab(ino);
                fp->fi_id = current_fileid++;
                return fp;
        }
        return NULL;
}

static void
nfsd4_free_slab(kmem_cache_t **slab)
{
        int status;

        if (*slab == NULL)
                return;
        status = kmem_cache_destroy(*slab);
        *slab = NULL;
        WARN_ON(status);
}

static void
nfsd4_free_slabs(void)
{
        nfsd4_free_slab(&stateowner_slab);
        nfsd4_free_slab(&file_slab);
        nfsd4_free_slab(&stateid_slab);
        nfsd4_free_slab(&deleg_slab);
}

static int
nfsd4_init_slabs(void)
{
        stateowner_slab = kmem_cache_create("nfsd4_stateowners",
                        sizeof(struct nfs4_stateowner), 0, 0, NULL, NULL);
        if (stateowner_slab == NULL)
                goto out_nomem;
        file_slab = kmem_cache_create("nfsd4_files",
                        sizeof(struct nfs4_file), 0, 0, NULL, NULL);
        if (file_slab == NULL)
                goto out_nomem;
        stateid_slab = kmem_cache_create("nfsd4_stateids",
                        sizeof(struct nfs4_stateid), 0, 0, NULL, NULL);
        if (stateid_slab == NULL)
                goto out_nomem;
        deleg_slab = kmem_cache_create("nfsd4_delegations",
                        sizeof(struct nfs4_delegation), 0, 0, NULL, NULL);
        if (deleg_slab == NULL)
                goto out_nomem;
        return 0;
out_nomem:
        nfsd4_free_slabs();
        dprintk("nfsd4: out of memory while initializing nfsv4\n");
        return -ENOMEM;
}

void
nfs4_free_stateowner(struct kref *kref)
{
        struct nfs4_stateowner *sop =
                container_of(kref, struct nfs4_stateowner, so_ref);
        kfree(sop->so_owner.data);
        kmem_cache_free(stateowner_slab, sop);
}

static inline struct nfs4_stateowner *
alloc_stateowner(struct xdr_netobj *owner)
{
        struct nfs4_stateowner *sop;

        if ((sop = kmem_cache_alloc(stateowner_slab, GFP_KERNEL))) {
                if ((sop->so_owner.data = kmalloc(owner->len, GFP_KERNEL))) {
                        memcpy(sop->so_owner.data, owner->data, owner->len);
                        sop->so_owner.len = owner->len;
                        kref_init(&sop->so_ref);
                        return sop;
                } 
                kmem_cache_free(stateowner_slab, sop);
        }
        return NULL;
}

static struct nfs4_stateowner *
alloc_init_open_stateowner(unsigned int strhashval, struct nfs4_client *clp, struct nfsd4_open *open) {
        struct nfs4_stateowner *sop;
        struct nfs4_replay *rp;
        unsigned int idhashval;

        if (!(sop = alloc_stateowner(&open->op_owner)))
                return NULL;
        idhashval = ownerid_hashval(current_ownerid);
        INIT_LIST_HEAD(&sop->so_idhash);
        INIT_LIST_HEAD(&sop->so_strhash);
        INIT_LIST_HEAD(&sop->so_perclient);
        INIT_LIST_HEAD(&sop->so_perfilestate);
        INIT_LIST_HEAD(&sop->so_perlockowner);  /* not used */
        INIT_LIST_HEAD(&sop->so_close_lru);
        sop->so_time = 0;
        list_add(&sop->so_idhash, &ownerid_hashtbl[idhashval]);
        list_add(&sop->so_strhash, &ownerstr_hashtbl[strhashval]);
        list_add(&sop->so_perclient, &clp->cl_perclient);
        sop->so_is_open_owner = 1;
        sop->so_id = current_ownerid++;
        sop->so_client = clp;
        sop->so_seqid = open->op_seqid;
        sop->so_confirmed = 0;
        rp = &sop->so_replay;
        rp->rp_status = NFSERR_SERVERFAULT;
        rp->rp_buflen = 0;
        rp->rp_buf = rp->rp_ibuf;
        return sop;
}

static void
release_stateid_lockowners(struct nfs4_stateid *open_stp)
{
        struct nfs4_stateowner *lock_sop;

        while (!list_empty(&open_stp->st_perlockowner)) {
                lock_sop = list_entry(open_stp->st_perlockowner.next,
                                struct nfs4_stateowner, so_perlockowner);
                /* list_del(&open_stp->st_perlockowner);  */
                BUG_ON(lock_sop->so_is_open_owner);
                release_stateowner(lock_sop);
        }
}

static void
unhash_stateowner(struct nfs4_stateowner *sop)
{
        struct nfs4_stateid *stp;

        list_del(&sop->so_idhash);
        list_del(&sop->so_strhash);
        if (sop->so_is_open_owner)
                list_del(&sop->so_perclient);
        list_del(&sop->so_perlockowner);
        while (!list_empty(&sop->so_perfilestate)) {
                stp = list_entry(sop->so_perfilestate.next, 
                        struct nfs4_stateid, st_perfilestate);
                if (sop->so_is_open_owner)
                        release_stateid(stp, OPEN_STATE);
                else
                        release_stateid(stp, LOCK_STATE);
        }
}

static void
release_stateowner(struct nfs4_stateowner *sop)
{
        unhash_stateowner(sop);
        list_del(&sop->so_close_lru);
        nfs4_put_stateowner(sop);
}

static inline void
init_stateid(struct nfs4_stateid *stp, struct nfs4_file *fp, struct nfsd4_open *open) {
        struct nfs4_stateowner *sop = open->op_stateowner;
        unsigned int hashval = stateid_hashval(sop->so_id, fp->fi_id);

        INIT_LIST_HEAD(&stp->st_hash);
        INIT_LIST_HEAD(&stp->st_perfilestate);
        INIT_LIST_HEAD(&stp->st_perlockowner);
        INIT_LIST_HEAD(&stp->st_perfile);
        list_add(&stp->st_hash, &stateid_hashtbl[hashval]);
        list_add(&stp->st_perfilestate, &sop->so_perfilestate);
        list_add(&stp->st_perfile, &fp->fi_stateids);
        stp->st_stateowner = sop;
        get_nfs4_file(fp);
        stp->st_file = fp;
        stp->st_stateid.si_boot = boot_time;
        stp->st_stateid.si_stateownerid = sop->so_id;
        stp->st_stateid.si_fileid = fp->fi_id;
        stp->st_stateid.si_generation = 0;
        stp->st_access_bmap = 0;
        stp->st_deny_bmap = 0;
        __set_bit(open->op_share_access, &stp->st_access_bmap);
        __set_bit(open->op_share_deny, &stp->st_deny_bmap);
}

static void
release_stateid(struct nfs4_stateid *stp, int flags)
{
        struct file *filp = stp->st_vfs_file;

        list_del(&stp->st_hash);
        list_del(&stp->st_perfile);
        list_del(&stp->st_perfilestate);
        if (flags & OPEN_STATE) {
                release_stateid_lockowners(stp);
                stp->st_vfs_file = NULL;
                nfsd_close(filp);
        } else if (flags & LOCK_STATE)
                locks_remove_posix(filp, (fl_owner_t) stp->st_stateowner);
        put_nfs4_file(stp->st_file);
        kmem_cache_free(stateid_slab, stp);
        stp = NULL;
}

void
move_to_close_lru(struct nfs4_stateowner *sop)
{
        dprintk("NFSD: move_to_close_lru nfs4_stateowner %p\n", sop);

        unhash_stateowner(sop);
        list_add_tail(&sop->so_close_lru, &close_lru);
        sop->so_time = get_seconds();
}

void
release_state_owner(struct nfs4_stateid *stp, int flag)
{
        struct nfs4_stateowner *sop = stp->st_stateowner;

        dprintk("NFSD: release_state_owner\n");
        release_stateid(stp, flag);

        /* place unused nfs4_stateowners on so_close_lru list to be
         * released by the laundromat service after the lease period
         * to enable us to handle CLOSE replay
         */
        if (sop->so_confirmed && list_empty(&sop->so_perfilestate))
                move_to_close_lru(sop);
}

static int
cmp_owner_str(struct nfs4_stateowner *sop, struct xdr_netobj *owner, clientid_t *clid) {
        return ((sop->so_owner.len == owner->len) && 
         !memcmp(sop->so_owner.data, owner->data, owner->len) && 
          (sop->so_client->cl_clientid.cl_id == clid->cl_id));
}

static struct nfs4_stateowner *
find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open)
{
        struct nfs4_stateowner *so = NULL;

        list_for_each_entry(so, &ownerstr_hashtbl[hashval], so_strhash) {
                if (cmp_owner_str(so, &open->op_owner, &open->op_clientid))
                        return so;
        }
        return NULL;
}

/* search file_hashtbl[] for file */
static struct nfs4_file *
find_file(struct inode *ino)
{
        unsigned int hashval = file_hashval(ino);
        struct nfs4_file *fp;

        list_for_each_entry(fp, &file_hashtbl[hashval], fi_hash) {
                if (fp->fi_inode == ino) {
                        get_nfs4_file(fp);
                        return fp;
                }
        }
        return NULL;
}

#define TEST_ACCESS(x) ((x > 0 || x < 4)?1:0)
#define TEST_DENY(x) ((x >= 0 || x < 5)?1:0)

void
set_access(unsigned int *access, unsigned long bmap) {
        int i;

        *access = 0;
        for (i = 1; i < 4; i++) {
                if (test_bit(i, &bmap))
                        *access |= i;
        }
}

void
set_deny(unsigned int *deny, unsigned long bmap) {
        int i;

        *deny = 0;
        for (i = 0; i < 4; i++) {
                if (test_bit(i, &bmap))
                        *deny |= i ;
        }
}

static int
test_share(struct nfs4_stateid *stp, struct nfsd4_open *open) {
        unsigned int access, deny;

        set_access(&access, stp->st_access_bmap);
        set_deny(&deny, stp->st_deny_bmap);
        if ((access & open->op_share_deny) || (deny & open->op_share_access))
                return 0;
        return 1;
}

/*
 * Called to check deny when READ with all zero stateid or
 * WRITE with all zero or all one stateid
 */
int
nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type)
{
        struct inode *ino = current_fh->fh_dentry->d_inode;
        struct nfs4_file *fp;
        struct nfs4_stateid *stp;
        int ret;

        dprintk("NFSD: nfs4_share_conflict\n");

        fp = find_file(ino);
        if (!fp)
                return nfs_ok;
        ret = nfserr_share_denied;
        /* Search for conflicting share reservations */
        list_for_each_entry(stp, &fp->fi_stateids, st_perfile) {
                if (test_bit(deny_type, &stp->st_deny_bmap) ||
                    test_bit(NFS4_SHARE_DENY_BOTH, &stp->st_deny_bmap))
                        goto out;
        }
        ret = nfs_ok;
out:
        put_nfs4_file(fp);
        return ret;
}

static inline void
nfs4_file_downgrade(struct file *filp, unsigned int share_access)
{
        if (share_access & NFS4_SHARE_ACCESS_WRITE) {
                put_write_access(filp->f_dentry->d_inode);
                filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE;
        }
}

/*
 * Recall a delegation
 */
static int
do_recall(void *__dp)
{
        struct nfs4_delegation *dp = __dp;

        daemonize("nfsv4-recall");

        nfsd4_cb_recall(dp);
        return 0;
}

/*
 * Spawn a thread to perform a recall on the delegation represented
 * by the lease (file_lock)
 *
 * Called from break_lease() with lock_kernel() held.
 * Note: we assume break_lease will only call this *once* for any given
 * lease.
 */
static
void nfsd_break_deleg_cb(struct file_lock *fl)
{
        struct nfs4_delegation *dp=  (struct nfs4_delegation *)fl->fl_owner;
        struct task_struct *t;

        dprintk("NFSD nfsd_break_deleg_cb: dp %p fl %p\n",dp,fl);
        if (!dp)
                return;

        /* We're assuming the state code never drops its reference
         * without first removing the lease.  Since we're in this lease
         * callback (and since the lease code is serialized by the kernel
         * lock) we know the server hasn't removed the lease yet, we know
         * it's safe to take a reference: */
        atomic_inc(&dp->dl_count);

        spin_lock(&recall_lock);
        list_add_tail(&dp->dl_recall_lru, &del_recall_lru);
        spin_unlock(&recall_lock);

        /* only place dl_time is set. protected by lock_kernel*/
        dp->dl_time = get_seconds();

        /* XXX need to merge NFSD_LEASE_TIME with fs/locks.c:lease_break_time */
        fl->fl_break_time = jiffies + NFSD_LEASE_TIME * HZ;

        t = kthread_run(do_recall, dp, "%s", "nfs4_cb_recall");
        if (IS_ERR(t)) {
                struct nfs4_client *clp = dp->dl_client;

                printk(KERN_INFO "NFSD: Callback thread failed for "
                        "for client (clientid %08x/%08x)\n",
                        clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);
                nfs4_put_delegation(dp);
        }
}

/*
 * The file_lock is being reapd.
 *
 * Called by locks_free_lock() with lock_kernel() held.
 */
static
void nfsd_release_deleg_cb(struct file_lock *fl)
{
        struct nfs4_delegation *dp = (struct nfs4_delegation *)fl->fl_owner;

        dprintk("NFSD nfsd_release_deleg_cb: fl %p dp %p dl_count %d\n", fl,dp, atomic_read(&dp->dl_count));

        if (!(fl->fl_flags & FL_LEASE) || !dp)
                return;
        dp->dl_flock = NULL;
}

/*
 * Set the delegation file_lock back pointer.
 *
 * Called from __setlease() with lock_kernel() held.
 */
static
void nfsd_copy_lock_deleg_cb(struct file_lock *new, struct file_lock *fl)
{
        struct nfs4_delegation *dp = (struct nfs4_delegation *)new->fl_owner;

        dprintk("NFSD: nfsd_copy_lock_deleg_cb: new fl %p dp %p\n", new, dp);
        if (!dp)
                return;
        dp->dl_flock = new;
}

/*
 * Called from __setlease() with lock_kernel() held
 */
static
int nfsd_same_client_deleg_cb(struct file_lock *onlist, struct file_lock *try)
{
        struct nfs4_delegation *onlistd =
                (struct nfs4_delegation *)onlist->fl_owner;
        struct nfs4_delegation *tryd =
                (struct nfs4_delegation *)try->fl_owner;

        if (onlist->fl_lmops != try->fl_lmops)
                return 0;

        return onlistd->dl_client == tryd->dl_client;
}


static
int nfsd_change_deleg_cb(struct file_lock **onlist, int arg)
{
        if (arg & F_UNLCK)
                return lease_modify(onlist, arg);
        else
                return -EAGAIN;
}

struct lock_manager_operations nfsd_lease_mng_ops = {
        .fl_break = nfsd_break_deleg_cb,
        .fl_release_private = nfsd_release_deleg_cb,
        .fl_copy_lock = nfsd_copy_lock_deleg_cb,
        .fl_mylease = nfsd_same_client_deleg_cb,
        .fl_change = nfsd_change_deleg_cb,
};


/*
 * nfsd4_process_open1()
 *      lookup stateowner.
 *              found:
 *                      check confirmed 
 *                              confirmed:
 *                                      check seqid
 *                              not confirmed:
 *                                      delete owner
 *                                      create new owner
 *              notfound:
 *                      verify clientid
 *                      create new owner
 *
 * called with nfs4_lock_state() held.
 */
int
nfsd4_process_open1(struct nfsd4_open *open)
{
        int status;
        clientid_t *clientid = &open->op_clientid;
        struct nfs4_client *clp = NULL;
        unsigned int strhashval;
        struct nfs4_stateowner *sop = NULL;

        status = nfserr_inval;
        if (!check_name(open->op_owner))
                goto out;

        if (STALE_CLIENTID(&open->op_clientid))
                return nfserr_stale_clientid;

        strhashval = ownerstr_hashval(clientid->cl_id, open->op_owner);
        sop = find_openstateowner_str(strhashval, open);
        if (sop) {
                open->op_stateowner = sop;
                /* check for replay */
                if (open->op_seqid == sop->so_seqid){
                        if (sop->so_replay.rp_buflen)
                                return NFSERR_REPLAY_ME;
                        else {
                                /* The original OPEN failed so spectacularly
                                 * that we don't even have replay data saved!
                                 * Therefore, we have no choice but to continue
                                 * processing this OPEN; presumably, we'll
                                 * fail again for the same reason.
                                 */
                                dprintk("nfsd4_process_open1:"
                                        " replay with no replay cache\n");
                                goto renew;
                        }
                } else if (sop->so_confirmed) {
                        if (open->op_seqid == sop->so_seqid + 1)
                                goto renew;
                        status = nfserr_bad_seqid;
                        goto out;
                } else {
                        /* If we get here, we received an OPEN for an
                         * unconfirmed nfs4_stateowner. Since the seqid's are
                         * different, purge the existing nfs4_stateowner, and
                         * instantiate a new one.
                         */
                        clp = sop->so_client;
                        release_stateowner(sop);
                }
        } else {
                /* nfs4_stateowner not found.
                 * Verify clientid and instantiate new nfs4_stateowner.
                 * If verify fails this is presumably the result of the
                 * client's lease expiring.
                 */
                status = nfserr_expired;
                clp = find_confirmed_client(clientid);
                if (clp == NULL)
                        goto out;
        }
        status = nfserr_resource;
        sop = alloc_init_open_stateowner(strhashval, clp, open);
        if (sop == NULL)
                goto out;
        open->op_stateowner = sop;
renew:
        status = nfs_ok;
        renew_client(sop->so_client);
out:
        if (status && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
                status = nfserr_reclaim_bad;
        return status;
}

static inline int
nfs4_check_delegmode(struct nfs4_delegation *dp, int flags)
{
        if ((flags & WR_STATE) && (dp->dl_type == NFS4_OPEN_DELEGATE_READ))
                return nfserr_openmode;
        else
                return nfs_ok;
}

static struct nfs4_delegation *
find_delegation_file(struct nfs4_file *fp, stateid_t *stid)
{
        struct nfs4_delegation *dp;

        list_for_each_entry(dp, &fp->fi_delegations, dl_del_perfile) {
                if (dp->dl_stateid.si_stateownerid == stid->si_stateownerid)
                        return dp;
        }
        return NULL;
}

static int
nfs4_check_deleg(struct nfs4_file *fp, struct nfsd4_open *open,
                struct nfs4_delegation **dp)
{
        int flags;
        int status = nfserr_bad_stateid;

        *dp = find_delegation_file(fp, &open->op_delegate_stateid);
        if (*dp == NULL)
                goto out;
        flags = open->op_share_access == NFS4_SHARE_ACCESS_READ ?
                                                RD_STATE : WR_STATE;
        status = nfs4_check_delegmode(*dp, flags);
        if (status)
                *dp = NULL;
out:
        if (open->op_claim_type != NFS4_OPEN_CLAIM_DELEGATE_CUR)
                return nfs_ok;
        if (status)
                return status;
        open->op_stateowner->so_confirmed = 1;
        return nfs_ok;
}

static int
nfs4_check_open(struct nfs4_file *fp, struct nfsd4_open *open, struct nfs4_stateid **stpp)
{
        struct nfs4_stateid *local;
        int status = nfserr_share_denied;
        struct nfs4_stateowner *sop = open->op_stateowner;

        list_for_each_entry(local, &fp->fi_stateids, st_perfile) {
                /* ignore lock owners */
                if (local->st_stateowner->so_is_open_owner == 0)
                        continue;
                /* remember if we have seen this open owner */
                if (local->st_stateowner == sop)
                        *stpp = local;
                /* check for conflicting share reservations */
                if (!test_share(local, open))
                        goto out;
        }
        status = 0;
out:
        return status;
}

static inline struct nfs4_stateid *
nfs4_alloc_stateid(void)
{
        return kmem_cache_alloc(stateid_slab, GFP_KERNEL);
}

static int
nfs4_new_open(struct svc_rqst *rqstp, struct nfs4_stateid **stpp,
                struct nfs4_delegation *dp,
                struct svc_fh *cur_fh, int flags)
{
        struct nfs4_stateid *stp;

        stp = nfs4_alloc_stateid();
        if (stp == NULL)
                return nfserr_resource;

        if (dp) {
                get_file(dp->dl_vfs_file);
                stp->st_vfs_file = dp->dl_vfs_file;
        } else {
                int status;
                status = nfsd_open(rqstp, cur_fh, S_IFREG, flags,
                                &stp->st_vfs_file);
                if (status) {
                        if (status == nfserr_dropit)
                                status = nfserr_jukebox;
                        kmem_cache_free(stateid_slab, stp);
                        return status;
                }
        }
        *stpp = stp;
        return 0;
}

static inline int
nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
                struct nfsd4_open *open)
{
        struct iattr iattr = {
                .ia_valid = ATTR_SIZE,
                .ia_size = 0,
        };
        if (!open->op_truncate)
                return 0;
        if (!(open->op_share_access & NFS4_SHARE_ACCESS_WRITE))
                return -EINVAL;
        return nfsd_setattr(rqstp, fh, &iattr, 0, (time_t)0);
}

static int
nfs4_upgrade_open(struct svc_rqst *rqstp, struct svc_fh *cur_fh, struct nfs4_stateid *stp, struct nfsd4_open *open)
{
        struct file *filp = stp->st_vfs_file;
        struct inode *inode = filp->f_dentry->d_inode;
        unsigned int share_access;
        int status;

        set_access(&share_access, stp->st_access_bmap);
        share_access = ~share_access;
        share_access &= open->op_share_access;

        if (!(share_access & NFS4_SHARE_ACCESS_WRITE))
                return nfsd4_truncate(rqstp, cur_fh, open);

        status = get_write_access(inode);
        if (status)
                return nfserrno(status);
        status = nfsd4_truncate(rqstp, cur_fh, open);
        if (status) {
                put_write_access(inode);
                return status;
        }
        /* remember the open */
        filp->f_mode = (filp->f_mode | FMODE_WRITE) & ~FMODE_READ;
        set_bit(open->op_share_access, &stp->st_access_bmap);
        set_bit(open->op_share_deny, &stp->st_deny_bmap);

        return nfs_ok;
}


/* decrement seqid on successful reclaim, it will be bumped in encode_open */
static void
nfs4_set_claim_prev(struct nfsd4_open *open, int *status)
{
        if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS) {
                if (*status)
                        *status = nfserr_reclaim_bad;
                else {
                        open->op_stateowner->so_confirmed = 1;
                        open->op_stateowner->so_seqid--;
                }
        }
}

/*
 * Attempt to hand out a delegation.
 */
static void
nfs4_open_delegation(struct svc_fh *fh, struct nfsd4_open *open, struct nfs4_stateid *stp)
{
        struct nfs4_delegation *dp;
        struct nfs4_stateowner *sop = stp->st_stateowner;
        struct nfs4_callback *cb = &sop->so_client->cl_callback;
        struct file_lock fl, *flp = &fl;
        int status, flag = 0;

        flag = NFS4_OPEN_DELEGATE_NONE;
        open->op_recall = 0;
        switch (open->op_claim_type) {
                case NFS4_OPEN_CLAIM_PREVIOUS:
                        if (!atomic_read(&cb->cb_set))
                                open->op_recall = 1;
                        flag = open->op_delegate_type;
                        if (flag == NFS4_OPEN_DELEGATE_NONE)
                                goto out;
                        break;
                case NFS4_OPEN_CLAIM_NULL:
                        /* Let's not give out any delegations till everyone's
                         * had the chance to reclaim theirs.... */
                        if (nfs4_in_grace())
                                goto out;
                        if (!atomic_read(&cb->cb_set) || !sop->so_confirmed)
                                goto out;
                        if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
                                flag = NFS4_OPEN_DELEGATE_WRITE;
                        else
                                flag = NFS4_OPEN_DELEGATE_READ;
                        break;
                default:
                        goto out;
        }

        dp = alloc_init_deleg(sop->so_client, stp, fh, flag);
        if (dp == NULL) {
                flag = NFS4_OPEN_DELEGATE_NONE;
                goto out;
        }
        locks_init_lock(&fl);
        fl.fl_lmops = &nfsd_lease_mng_ops;
        fl.fl_flags = FL_LEASE;
        fl.fl_end = OFFSET_MAX;
        fl.fl_owner =  (fl_owner_t)dp;
        fl.fl_file = stp->st_vfs_file;
        fl.fl_pid = current->tgid;

        /* setlease checks to see if delegation should be handed out.
         * the lock_manager callbacks fl_mylease and fl_change are used
         */
        if ((status = setlease(stp->st_vfs_file,
                flag == NFS4_OPEN_DELEGATE_READ? F_RDLCK: F_WRLCK, &flp))) {
                dprintk("NFSD: setlease failed [%d], no delegation\n", status);
                unhash_delegation(dp);
                flag = NFS4_OPEN_DELEGATE_NONE;
                goto out;
        }

        memcpy(&open->op_delegate_stateid, &dp->dl_stateid, sizeof(dp->dl_stateid));

        dprintk("NFSD: delegation stateid=(%08x/%08x/%08x/%08x)\n\n",
                     dp->dl_stateid.si_boot,
                     dp->dl_stateid.si_stateownerid,
                     dp->dl_stateid.si_fileid,
                     dp->dl_stateid.si_generation);
out:
        if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS
                        && flag == NFS4_OPEN_DELEGATE_NONE
                        && open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE)
                printk("NFSD: WARNING: refusing delegation reclaim\n");
        open->op_delegate_type = flag;
}

/*
 * called with nfs4_lock_state() held.
 */
int
nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
{
        struct nfs4_file *fp = NULL;
        struct inode *ino = current_fh->fh_dentry->d_inode;
        struct nfs4_stateid *stp = NULL;
        struct nfs4_delegation *dp = NULL;
        int status;

        status = nfserr_inval;
        if (!TEST_ACCESS(open->op_share_access) || !TEST_DENY(open->op_share_deny))
                goto out;
        /*
         * Lookup file; if found, lookup stateid and check open request,
         * and check for delegations in the process of being recalled.
         * If not found, create the nfs4_file struct
         */
        fp = find_file(ino);
        if (fp) {
                if ((status = nfs4_check_open(fp, open, &stp)))
                        goto out;
                status = nfs4_check_deleg(fp, open, &dp);
                if (status)
                        goto out;
        } else {
                status = nfserr_bad_stateid;
                if (open->op_claim_type == NFS4_OPEN_CLAIM_DELEGATE_CUR)
                        goto out;
                status = nfserr_resource;
                fp = alloc_init_file(ino);
                if (fp == NULL)
                        goto out;
        }

        /*
         * OPEN the file, or upgrade an existing OPEN.
         * If truncate fails, the OPEN fails.
         */
        if (stp) {
                /* Stateid was found, this is an OPEN upgrade */
                status = nfs4_upgrade_open(rqstp, current_fh, stp, open);
                if (status)
                        goto out;
        } else {
                /* Stateid was not found, this is a new OPEN */
                int flags = 0;
                if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
                        flags = MAY_WRITE;
                else
                        flags = MAY_READ;
                status = nfs4_new_open(rqstp, &stp, dp, current_fh, flags);
                if (status)
                        goto out;
                init_stateid(stp, fp, open);
                status = nfsd4_truncate(rqstp, current_fh, open);
                if (status) {
                        release_stateid(stp, OPEN_STATE);
                        goto out;
                }
        }
        memcpy(&open->op_stateid, &stp->st_stateid, sizeof(stateid_t));

        /*
        * Attempt to hand out a delegation. No error return, because the
        * OPEN succeeds even if we fail.
        */
        nfs4_open_delegation(current_fh, open, stp);

        status = nfs_ok;

        dprintk("nfs4_process_open2: stateid=(%08x/%08x/%08x/%08x)\n",
                    stp->st_stateid.si_boot, stp->st_stateid.si_stateownerid,
                    stp->st_stateid.si_fileid, stp->st_stateid.si_generation);
out:
        if (fp)
                put_nfs4_file(fp);
        /* CLAIM_PREVIOUS has different error returns */
        nfs4_set_claim_prev(open, &status);
        /*
        * To finish the open response, we just need to set the rflags.
        */
        open->op_rflags = NFS4_OPEN_RESULT_LOCKTYPE_POSIX;
        if (!open->op_stateowner->so_confirmed)
                open->op_rflags |= NFS4_OPEN_RESULT_CONFIRM;

        return status;
}

static struct workqueue_struct *laundry_wq;
static struct work_struct laundromat_work;
static void laundromat_main(void *);
static DECLARE_WORK(laundromat_work, laundromat_main, NULL);

int 
nfsd4_renew(clientid_t *clid)
{
        struct nfs4_client *clp;
        int status;

        nfs4_lock_state();
        dprintk("process_renew(%08x/%08x): starting\n", 
                        clid->cl_boot, clid->cl_id);
        status = nfserr_stale_clientid;
        if (STALE_CLIENTID(clid))
                goto out;
        clp = find_confirmed_client(clid);
        status = nfserr_expired;
        if (clp == NULL) {
                /* We assume the client took too long to RENEW. */
                dprintk("nfsd4_renew: clientid not found!\n");
                goto out;
        }
        renew_client(clp);
        status = nfserr_cb_path_down;
        if (!list_empty(&clp->cl_del_perclnt)
                        && !atomic_read(&clp->cl_callback.cb_set))
                goto out;
        status = nfs_ok;
out:
        nfs4_unlock_state();
        return status;
}

time_t
nfs4_laundromat(void)
{
        struct nfs4_client *clp;
        struct nfs4_stateowner *sop;
        struct nfs4_delegation *dp;
        struct list_head *pos, *next, reaplist;
        time_t cutoff = get_seconds() - NFSD_LEASE_TIME;
        time_t t, clientid_val = NFSD_LEASE_TIME;
        time_t u, test_val = NFSD_LEASE_TIME;

        nfs4_lock_state();

        dprintk("NFSD: laundromat service - starting\n");
        list_for_each_safe(pos, next, &client_lru) {
                clp = list_entry(pos, struct nfs4_client, cl_lru);
                if (time_after((unsigned long)clp->cl_time, (unsigned long)cutoff)) {
                        t = clp->cl_time - cutoff;
                        if (clientid_val > t)
                                clientid_val = t;
                        break;
                }
                dprintk("NFSD: purging unused client (clientid %08x)\n",
                        clp->cl_clientid.cl_id);
                expire_client(clp);
        }
        INIT_LIST_HEAD(&reaplist);
        spin_lock(&recall_lock);
        list_for_each_safe(pos, next, &del_recall_lru) {
                dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
                if (time_after((unsigned long)dp->dl_time, (unsigned long)cutoff)) {
                        u = dp->dl_time - cutoff;
                        if (test_val > u)
                                test_val = u;
                        break;
                }
                dprintk("NFSD: purging unused delegation dp %p, fp %p\n",
                                    dp, dp->dl_flock);
                list_move(&dp->dl_recall_lru, &reaplist);
        }
        spin_unlock(&recall_lock);
        list_for_each_safe(pos, next, &reaplist) {
                dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
                list_del_init(&dp->dl_recall_lru);
                unhash_delegation(dp);
        }
        test_val = NFSD_LEASE_TIME;
        list_for_each_safe(pos, next, &close_lru) {
                sop = list_entry(pos, struct nfs4_stateowner, so_close_lru);
                if (time_after((unsigned long)sop->so_time, (unsigned long)cutoff)) {
                        u = sop->so_time - cutoff;
                        if (test_val > u)
                                test_val = u;
                        break;
                }
                dprintk("NFSD: purging unused open stateowner (so_id %d)\n",
                        sop->so_id);
                list_del(&sop->so_close_lru);
                nfs4_put_stateowner(sop);
        }
        if (clientid_val < NFSD_LAUNDROMAT_MINTIMEOUT)
                clientid_val = NFSD_LAUNDROMAT_MINTIMEOUT;
        nfs4_unlock_state();
        return clientid_val;
}

void
laundromat_main(void *not_used)
{
        time_t t;

        t = nfs4_laundromat();
        dprintk("NFSD: laundromat_main - sleeping for %ld seconds\n", t);
        queue_delayed_work(laundry_wq, &laundromat_work, t*HZ);
}

/* search ownerid_hashtbl[] and close_lru for stateid owner
 * (stateid->si_stateownerid)
 */
struct nfs4_stateowner *
find_openstateowner_id(u32 st_id, int flags) {
        struct nfs4_stateowner *local = NULL;

        dprintk("NFSD: find_openstateowner_id %d\n", st_id);
        if (flags & CLOSE_STATE) {
                list_for_each_entry(local, &close_lru, so_close_lru) {
                        if (local->so_id == st_id)
                                return local;
                }
        }
        return NULL;
}

static inline int
nfs4_check_fh(struct svc_fh *fhp, struct nfs4_stateid *stp)
{
        return fhp->fh_dentry->d_inode != stp->st_vfs_file->f_dentry->d_inode;
}

static int
STALE_STATEID(stateid_t *stateid)
{
        if (stateid->si_boot == boot_time)
                return 0;
        printk("NFSD: stale stateid (%08x/%08x/%08x/%08x)!\n",
                stateid->si_boot, stateid->si_stateownerid, stateid->si_fileid,
                stateid->si_generation);
        return 1;
}

static inline int
access_permit_read(unsigned long access_bmap)
{
        return test_bit(NFS4_SHARE_ACCESS_READ, &access_bmap) ||
                test_bit(NFS4_SHARE_ACCESS_BOTH, &access_bmap) ||
                test_bit(NFS4_SHARE_ACCESS_WRITE, &access_bmap);
}

static inline int
access_permit_write(unsigned long access_bmap)
{
        return test_bit(NFS4_SHARE_ACCESS_WRITE, &access_bmap) ||
                test_bit(NFS4_SHARE_ACCESS_BOTH, &access_bmap);
}

static
int nfs4_check_openmode(struct nfs4_stateid *stp, int flags)
{
        int status = nfserr_openmode;

        if ((flags & WR_STATE) && (!access_permit_write(stp->st_access_bmap)))
                goto out;
        if ((flags & RD_STATE) && (!access_permit_read(stp->st_access_bmap)))
                goto out;
        status = nfs_ok;
out:
        return status;
}

static inline int
check_special_stateids(svc_fh *current_fh, stateid_t *stateid, int flags)
{
        /* Trying to call delegreturn with a special stateid? Yuch: */
        if (!(flags & (RD_STATE | WR_STATE)))
                return nfserr_bad_stateid;
        else if (ONE_STATEID(stateid) && (flags & RD_STATE))
                return nfs_ok;
        else if (nfs4_in_grace()) {
                /* Answer in remaining cases depends on existance of
                 * conflicting state; so we must wait out the grace period. */
                return nfserr_grace;
        } else if (flags & WR_STATE)
                return nfs4_share_conflict(current_fh,
                                NFS4_SHARE_DENY_WRITE);
        else /* (flags & RD_STATE) && ZERO_STATEID(stateid) */
                return nfs4_share_conflict(current_fh,
                                NFS4_SHARE_DENY_READ);
}

/*
 * Allow READ/WRITE during grace period on recovered state only for files
 * that are not able to provide mandatory locking.
 */
static inline int
io_during_grace_disallowed(struct inode *inode, int flags)
{
        return nfs4_in_grace() && (flags & (RD_STATE | WR_STATE))
                && MANDATORY_LOCK(inode);
}

/*
* Checks for stateid operations
*/
int
nfs4_preprocess_stateid_op(struct svc_fh *current_fh, stateid_t *stateid, int flags, struct file **filpp)
{
        struct nfs4_stateid *stp = NULL;
        struct nfs4_delegation *dp = NULL;
        stateid_t *stidp;
        struct inode *ino = current_fh->fh_dentry->d_inode;
        int status;

        dprintk("NFSD: preprocess_stateid_op: stateid = (%08x/%08x/%08x/%08x)\n",
                stateid->si_boot, stateid->si_stateownerid, 
                stateid->si_fileid, stateid->si_generation); 
        if (filpp)
                *filpp = NULL;

        if (io_during_grace_disallowed(ino, flags))
                return nfserr_grace;

        if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
                return check_special_stateids(current_fh, stateid, flags);

        /* STALE STATEID */
        status = nfserr_stale_stateid;
        if (STALE_STATEID(stateid)) 
                goto out;

        /* BAD STATEID */
        status = nfserr_bad_stateid;
        if (!stateid->si_fileid) { /* delegation stateid */
                if(!(dp = find_delegation_stateid(ino, stateid))) {
                        dprintk("NFSD: delegation stateid not found\n");
                        if (nfs4_in_grace())
                                status = nfserr_grace;
                        goto out;
                }
                stidp = &dp->dl_stateid;
        } else { /* open or lock stateid */
                if (!(stp = find_stateid(stateid, flags))) {
                        dprintk("NFSD: open or lock stateid not found\n");
                        if (nfs4_in_grace())
                                status = nfserr_grace;
                        goto out;
                }
                if ((flags & CHECK_FH) && nfs4_check_fh(current_fh, stp))
                        goto out;
                if (!stp->st_stateowner->so_confirmed)
                        goto out;
                stidp = &stp->st_stateid;
        }
        if (stateid->si_generation > stidp->si_generation)
                goto out;

        /* OLD STATEID */
        status = nfserr_old_stateid;
        if (stateid->si_generation < stidp->si_generation)
                goto out;
        if (stp) {
                if ((status = nfs4_check_openmode(stp,flags)))
                        goto out;
                renew_client(stp->st_stateowner->so_client);
                if (filpp)
                        *filpp = stp->st_vfs_file;
        } else if (dp) {
                if ((status = nfs4_check_delegmode(dp, flags)))
                        goto out;
                renew_client(dp->dl_client);
                if (flags & DELEG_RET)
                        unhash_delegation(dp);
                if (filpp)
                        *filpp = dp->dl_vfs_file;
        }
        status = nfs_ok;
out:
        return status;
}


/* 
 * Checks for sequence id mutating operations. 
 */
int
nfs4_preprocess_seqid_op(struct svc_fh *current_fh, u32 seqid, stateid_t *stateid, int flags, struct nfs4_stateowner **sopp, struct nfs4_stateid **stpp, clientid_t *lockclid)
{
        int status;
        struct nfs4_stateid *stp;
        struct nfs4_stateowner *sop;

        dprintk("NFSD: preprocess_seqid_op: seqid=%d " 
                        "stateid = (%08x/%08x/%08x/%08x)\n", seqid,
                stateid->si_boot, stateid->si_stateownerid, stateid->si_fileid,
                stateid->si_generation);
                                
        *stpp = NULL;
        *sopp = NULL;

        status = nfserr_bad_stateid;
        if (ZERO_STATEID(stateid) || ONE_STATEID(stateid)) {
                printk("NFSD: preprocess_seqid_op: magic stateid!\n");
                goto out;
        }

        status = nfserr_stale_stateid;
        if (STALE_STATEID(stateid))
                goto out;
        /*
        * We return BAD_STATEID if filehandle doesn't match stateid, 
        * the confirmed flag is incorrecly set, or the generation 
        * number is incorrect.  
        * If there is no entry in the openfile table for this id, 
        * we can't always return BAD_STATEID;
        * this might be a retransmitted CLOSE which has arrived after 
        * the openfile has been released.
        */
        if (!(stp = find_stateid(stateid, flags)))
                goto no_nfs4_stateid;

        status = nfserr_bad_stateid;

        /* for new lock stateowners:
         * check that the lock->v.new.open_stateid
         * refers to an open stateowner
         *
         * check that the lockclid (nfs4_lock->v.new.clientid) is the same
         * as the open_stateid->st_stateowner->so_client->clientid
         */
        if (lockclid) {
                struct nfs4_stateowner *sop = stp->st_stateowner;
                struct nfs4_client *clp = sop->so_client;

                if (!sop->so_is_open_owner)
                        goto out;
                if (!cmp_clid(&clp->cl_clientid, lockclid))
                        goto out;
        }

        if ((flags & CHECK_FH) && nfs4_check_fh(current_fh, stp)) {
                printk("NFSD: preprocess_seqid_op: fh-stateid mismatch!\n");
                goto out;
        }

        *stpp = stp;
        *sopp = sop = stp->st_stateowner;

        /*
        *  We now validate the seqid and stateid generation numbers.
        *  For the moment, we ignore the possibility of 
        *  generation number wraparound.
        */
        if (seqid != sop->so_seqid + 1)
                goto check_replay;

        if (sop->so_confirmed) {
                if (flags & CONFIRM) {
                        printk("NFSD: preprocess_seqid_op: expected unconfirmed stateowner!\n");
                        goto out;
                }
        }
        else {
                if (!(flags & CONFIRM)) {
                        printk("NFSD: preprocess_seqid_op: stateowner not confirmed yet!\n");
                        goto out;
                }
        }
        if (stateid->si_generation > stp->st_stateid.si_generation) {
                printk("NFSD: preprocess_seqid_op: future stateid?!\n");
                goto out;
        }

        status = nfserr_old_stateid;
        if (stateid->si_generation < stp->st_stateid.si_generation) {
                printk("NFSD: preprocess_seqid_op: old stateid!\n");
                goto out;
        }
        /* XXX renew the client lease here */
        status = nfs_ok;

out:
        return status;

no_nfs4_stateid:

        /*
        * We determine whether this is a bad stateid or a replay, 
        * starting by trying to look up the stateowner.
        * If stateowner is not found - stateid is bad.
        */
        if (!(sop = find_openstateowner_id(stateid->si_stateownerid, flags))) {
                printk("NFSD: preprocess_seqid_op: no stateowner or nfs4_stateid!\n");
                status = nfserr_bad_stateid;
                goto out;
        }
        *sopp = sop;

check_replay:
        if (seqid == sop->so_seqid) {
                printk("NFSD: preprocess_seqid_op: retransmission?\n");
                /* indicate replay to calling function */
                status = NFSERR_REPLAY_ME;
        } else  {
                printk("NFSD: preprocess_seqid_op: bad seqid (expected %d, got %d\n", sop->so_seqid +1, seqid);

                *sopp = NULL;
                status = nfserr_bad_seqid;
        }
        goto out;
}

int
nfsd4_open_confirm(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open_confirm *oc)
{
        int status;
        struct nfs4_stateowner *sop;
        struct nfs4_stateid *stp;

        dprintk("NFSD: nfsd4_open_confirm on file %.*s\n",
                        (int)current_fh->fh_dentry->d_name.len,
                        current_fh->fh_dentry->d_name.name);

        if ((status = fh_verify(rqstp, current_fh, S_IFREG, 0)))
                goto out;

        nfs4_lock_state();

        if ((status = nfs4_preprocess_seqid_op(current_fh, oc->oc_seqid,
                                        &oc->oc_req_stateid,
                                        CHECK_FH | CONFIRM | OPEN_STATE,
                                        &oc->oc_stateowner, &stp, NULL)))
                goto out; 

        sop = oc->oc_stateowner;
        sop->so_confirmed = 1;
        update_stateid(&stp->st_stateid);
        memcpy(&oc->oc_resp_stateid, &stp->st_stateid, sizeof(stateid_t));
        dprintk("NFSD: nfsd4_open_confirm: success, seqid=%d " 
                "stateid=(%08x/%08x/%08x/%08x)\n", oc->oc_seqid,
                         stp->st_stateid.si_boot,
                         stp->st_stateid.si_stateownerid,
                         stp->st_stateid.si_fileid,
                         stp->st_stateid.si_generation);
out:
        if (oc->oc_stateowner)
                nfs4_get_stateowner(oc->oc_stateowner);
        nfs4_unlock_state();
        return status;
}


/*
 * unset all bits in union bitmap (bmap) that
 * do not exist in share (from successful OPEN_DOWNGRADE)
 */
static void
reset_union_bmap_access(unsigned long access, unsigned long *bmap)
{
        int i;
        for (i = 1; i < 4; i++) {
                if ((i & access) != i)
                        __clear_bit(i, bmap);
        }
}

static void
reset_union_bmap_deny(unsigned long deny, unsigned long *bmap)
{
        int i;
        for (i = 0; i < 4; i++) {
                if ((i & deny) != i)
                        __clear_bit(i, bmap);
        }
}

int
nfsd4_open_downgrade(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open_downgrade *od)
{
        int status;
        struct nfs4_stateid *stp;
        unsigned int share_access;

        dprintk("NFSD: nfsd4_open_downgrade on file %.*s\n", 
                        (int)current_fh->fh_dentry->d_name.len,
                        current_fh->fh_dentry->d_name.name);

        if (!TEST_ACCESS(od->od_share_access) || !TEST_DENY(od->od_share_deny))
                return nfserr_inval;

        nfs4_lock_state();
        if ((status = nfs4_preprocess_seqid_op(current_fh, od->od_seqid, 
                                        &od->od_stateid, 
                                        CHECK_FH | OPEN_STATE, 
                                        &od->od_stateowner, &stp, NULL)))
                goto out; 

        status = nfserr_inval;
        if (!test_bit(od->od_share_access, &stp->st_access_bmap)) {
                dprintk("NFSD:access not a subset current bitmap: 0x%lx, input access=%08x\n",
                        stp->st_access_bmap, od->od_share_access);
                goto out;
        }
        if (!test_bit(od->od_share_deny, &stp->st_deny_bmap)) {
                dprintk("NFSD:deny not a subset current bitmap: 0x%lx, input deny=%08x\n",
                        stp->st_deny_bmap, od->od_share_deny);
                goto out;
        }
        set_access(&share_access, stp->st_access_bmap);
        nfs4_file_downgrade(stp->st_vfs_file,
                            share_access & ~od->od_share_access);

        reset_union_bmap_access(od->od_share_access, &stp->st_access_bmap);
        reset_union_bmap_deny(od->od_share_deny, &stp->st_deny_bmap);

        update_stateid(&stp->st_stateid);
        memcpy(&od->od_stateid, &stp->st_stateid, sizeof(stateid_t));
        status = nfs_ok;
out:
        if (od->od_stateowner)
                nfs4_get_stateowner(od->od_stateowner);
        nfs4_unlock_state();
        return status;
}

/*
 * nfs4_unlock_state() called after encode
 */
int
nfsd4_close(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_close *close)
{
        int status;
        struct nfs4_stateid *stp;

        dprintk("NFSD: nfsd4_close on file %.*s\n", 
                        (int)current_fh->fh_dentry->d_name.len,
                        current_fh->fh_dentry->d_name.name);

        nfs4_lock_state();
        /* check close_lru for replay */
        if ((status = nfs4_preprocess_seqid_op(current_fh, close->cl_seqid, 
                                        &close->cl_stateid, 
                                        CHECK_FH | OPEN_STATE | CLOSE_STATE,
                                        &close->cl_stateowner, &stp, NULL)))
                goto out; 
        /*
        *  Return success, but first update the stateid.
        */
        status = nfs_ok;
        update_stateid(&stp->st_stateid);
        memcpy(&close->cl_stateid, &stp->st_stateid, sizeof(stateid_t));

        /* release_state_owner() calls nfsd_close() if needed */
        release_state_owner(stp, OPEN_STATE);
out:
        if (close->cl_stateowner)
                nfs4_get_stateowner(close->cl_stateowner);
        nfs4_unlock_state();
        return status;
}

int
nfsd4_delegreturn(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_delegreturn *dr)
{
        int status;

        if ((status = fh_verify(rqstp, current_fh, S_IFREG, 0)))
                goto out;

        nfs4_lock_state();
        status = nfs4_preprocess_stateid_op(current_fh, &dr->dr_stateid, DELEG_RET, NULL);
        nfs4_unlock_state();
out:
        return status;
}


/* 
 * Lock owner state (byte-range locks)
 */
#define LOFF_OVERFLOW(start, len)      ((u64)(len) > ~(u64)(start))
#define LOCK_HASH_BITS              8
#define LOCK_HASH_SIZE             (1 << LOCK_HASH_BITS)
#define LOCK_HASH_MASK             (LOCK_HASH_SIZE - 1)

#define lockownerid_hashval(id) \
        ((id) & LOCK_HASH_MASK)

static inline unsigned int
lock_ownerstr_hashval(struct inode *inode, u32 cl_id,
                struct xdr_netobj *ownername)
{
        return (file_hashval(inode) + cl_id
                        + opaque_hashval(ownername->data, ownername->len))
                & LOCK_HASH_MASK;
}

static struct list_head lock_ownerid_hashtbl[LOCK_HASH_SIZE];
static struct list_head lock_ownerstr_hashtbl[LOCK_HASH_SIZE];
static struct list_head lockstateid_hashtbl[STATEID_HASH_SIZE];

struct nfs4_stateid *
find_stateid(stateid_t *stid, int flags)
{
        struct nfs4_stateid *local = NULL;
        u32 st_id = stid->si_stateownerid;
        u32 f_id = stid->si_fileid;
        unsigned int hashval;

        dprintk("NFSD: find_stateid flags 0x%x\n",flags);
        if ((flags & LOCK_STATE) || (flags & RD_STATE) || (flags & WR_STATE)) {
                hashval = stateid_hashval(st_id, f_id);
                list_for_each_entry(local, &lockstateid_hashtbl[hashval], st_hash) {
                        if ((local->st_stateid.si_stateownerid == st_id) &&
                            (local->st_stateid.si_fileid == f_id))
                                return local;
                }
        } 
        if ((flags & OPEN_STATE) || (flags & RD_STATE) || (flags & WR_STATE)) {
                hashval = stateid_hashval(st_id, f_id);
                list_for_each_entry(local, &stateid_hashtbl[hashval], st_hash) {
                        if ((local->st_stateid.si_stateownerid == st_id) &&
                            (local->st_stateid.si_fileid == f_id))
                                return local;
                }
        } else
                printk("NFSD: find_stateid: ERROR: no state flag\n");
        return NULL;
}

static struct nfs4_delegation *
find_delegation_stateid(struct inode *ino, stateid_t *stid)
{
        struct nfs4_file *fp;
        struct nfs4_delegation *dl;

        dprintk("NFSD:find_delegation_stateid stateid=(%08x/%08x/%08x/%08x)\n",
                    stid->si_boot, stid->si_stateownerid,
                    stid->si_fileid, stid->si_generation);

        fp = find_file(ino);
        if (!fp)
                return NULL;
        dl = find_delegation_file(fp, stid);
        put_nfs4_file(fp);
        return dl;
}

/*
 * TODO: Linux file offsets are _signed_ 64-bit quantities, which means that
 * we can't properly handle lock requests that go beyond the (2^63 - 1)-th
 * byte, because of sign extension problems.  Since NFSv4 calls for 64-bit
 * locking, this prevents us from being completely protocol-compliant.  The
 * real solution to this problem is to start using unsigned file offsets in
 * the VFS, but this is a very deep change!
 */
static inline void
nfs4_transform_lock_offset(struct file_lock *lock)
{
        if (lock->fl_start < 0)
                lock->fl_start = OFFSET_MAX;
        if (lock->fl_end < 0)
                lock->fl_end = OFFSET_MAX;
}

int
nfs4_verify_lock_stateowner(struct nfs4_stateowner *sop, unsigned int hashval)
{
        struct nfs4_stateowner *local = NULL;
        int status = 0;
                                
        if (hashval >= LOCK_HASH_SIZE)
                goto out;
        list_for_each_entry(local, &lock_ownerid_hashtbl[hashval], so_idhash) {
                if (local == sop) {
                        status = 1;
                        goto out;
                }
        }
out:
        return status;
}


static inline void
nfs4_set_lock_denied(struct file_lock *fl, struct nfsd4_lock_denied *deny)
{
        struct nfs4_stateowner *sop = (struct nfs4_stateowner *) fl->fl_owner;
        unsigned int hval = lockownerid_hashval(sop->so_id);

        deny->ld_sop = NULL;
        if (nfs4_verify_lock_stateowner(sop, hval)) {
                kref_get(&sop->so_ref);
                deny->ld_sop = sop;
                deny->ld_clientid = sop->so_client->cl_clientid;
        }
        deny->ld_start = fl->fl_start;
        deny->ld_length = ~(u64)0;
        if (fl->fl_end != ~(u64)0)
                deny->ld_length = fl->fl_end - fl->fl_start + 1;        
        deny->ld_type = NFS4_READ_LT;
        if (fl->fl_type != F_RDLCK)
                deny->ld_type = NFS4_WRITE_LT;
}

static struct nfs4_stateowner *
find_lockstateowner(struct xdr_netobj *owner, clientid_t *clid)
{
        struct nfs4_stateowner *local = NULL;
        int i;

        for (i = 0; i < LOCK_HASH_SIZE; i++) {
                list_for_each_entry(local, &lock_ownerid_hashtbl[i], so_idhash) {
                        if (!cmp_owner_str(local, owner, clid))
                                continue;
                        return local;
                }
        }
        return NULL;
}

static struct nfs4_stateowner *
find_lockstateowner_str(struct inode *inode, clientid_t *clid,
                struct xdr_netobj *owner)
{
        unsigned int hashval = lock_ownerstr_hashval(inode, clid->cl_id, owner);
        struct nfs4_stateowner *op;

        list_for_each_entry(op, &lock_ownerstr_hashtbl[hashval], so_strhash) {
                if (cmp_owner_str(op, owner, clid))
                        return op;
        }
        return NULL;
}

/*
 * Alloc a lock owner structure.
 * Called in nfsd4_lock - therefore, OPEN and OPEN_CONFIRM (if needed) has 
 * occured. 
 *
 * strhashval = lock_ownerstr_hashval 
 * so_seqid = lock->lk_new_lock_seqid - 1: it gets bumped in encode 
 */

static struct nfs4_stateowner *
alloc_init_lock_stateowner(unsigned int strhashval, struct nfs4_client *clp, struct nfs4_stateid *open_stp, struct nfsd4_lock *lock) {
        struct nfs4_stateowner *sop;
        struct nfs4_replay *rp;
        unsigned int idhashval;

        if (!(sop = alloc_stateowner(&lock->lk_new_owner)))
                return NULL;
        idhashval = lockownerid_hashval(current_ownerid);
        INIT_LIST_HEAD(&sop->so_idhash);
        INIT_LIST_HEAD(&sop->so_strhash);
        INIT_LIST_HEAD(&sop->so_perclient);
        INIT_LIST_HEAD(&sop->so_perfilestate);
        INIT_LIST_HEAD(&sop->so_perlockowner);
        INIT_LIST_HEAD(&sop->so_close_lru); /* not used */
        sop->so_time = 0;
        list_add(&sop->so_idhash, &lock_ownerid_hashtbl[idhashval]);
        list_add(&sop->so_strhash, &lock_ownerstr_hashtbl[strhashval]);
        list_add(&sop->so_perlockowner, &open_stp->st_perlockowner);
        sop->so_is_open_owner = 0;
        sop->so_id = current_ownerid++;
        sop->so_client = clp;
        sop->so_seqid = lock->lk_new_lock_seqid - 1;
        sop->so_confirmed = 1;
        rp = &sop->so_replay;
        rp->rp_status = NFSERR_SERVERFAULT;
        rp->rp_buflen = 0;
        rp->rp_buf = rp->rp_ibuf;
        return sop;
}

struct nfs4_stateid *
alloc_init_lock_stateid(struct nfs4_stateowner *sop, struct nfs4_file *fp, struct nfs4_stateid *open_stp)
{
        struct nfs4_stateid *stp;
        unsigned int hashval = stateid_hashval(sop->so_id, fp->fi_id);

        stp = nfs4_alloc_stateid();
        if (stp == NULL)
                goto out;
        INIT_LIST_HEAD(&stp->st_hash);
        INIT_LIST_HEAD(&stp->st_perfile);
        INIT_LIST_HEAD(&stp->st_perfilestate);
        INIT_LIST_HEAD(&stp->st_perlockowner); /* not used */
        list_add(&stp->st_hash, &lockstateid_hashtbl[hashval]);
        list_add(&stp->st_perfile, &fp->fi_stateids);
        list_add(&stp->st_perfilestate, &sop->so_perfilestate);
        stp->st_stateowner = sop;
        get_nfs4_file(fp);
        stp->st_file = fp;
        stp->st_stateid.si_boot = boot_time;
        stp->st_stateid.si_stateownerid = sop->so_id;
        stp->st_stateid.si_fileid = fp->fi_id;
        stp->st_stateid.si_generation = 0;
        stp->st_vfs_file = open_stp->st_vfs_file; /* FIXME refcount?? */
        stp->st_access_bmap = open_stp->st_access_bmap;
        stp->st_deny_bmap = open_stp->st_deny_bmap;

out:
        return stp;
}

int
check_lock_length(u64 offset, u64 length)
{
        return ((length == 0)  || ((length != ~(u64)0) &&
             LOFF_OVERFLOW(offset, length)));
}

/*
 *  LOCK operation 
 */
int
nfsd4_lock(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lock *lock)
{
        struct nfs4_stateowner *lock_sop = NULL, *open_sop = NULL;
        struct nfs4_stateid *lock_stp;
        struct file *filp;
        struct file_lock file_lock;
        struct file_lock *conflock;
        int status = 0;
        unsigned int strhashval;

        dprintk("NFSD: nfsd4_lock: start=%Ld length=%Ld\n",
                (long long) lock->lk_offset,
                (long long) lock->lk_length);

        if (nfs4_in_grace() && !lock->lk_reclaim)
                return nfserr_grace;
        if (!nfs4_in_grace() && lock->lk_reclaim)
                return nfserr_no_grace;

        if (check_lock_length(lock->lk_offset, lock->lk_length))
                 return nfserr_inval;

        nfs4_lock_state();

        if (lock->lk_is_new) {
        /*
         * Client indicates that this is a new lockowner.
         * Use open owner and open stateid to create lock owner and lock 
         * stateid.
         */
                struct nfs4_stateid *open_stp = NULL;
                struct nfs4_file *fp;
                
                status = nfserr_stale_clientid;
                if (STALE_CLIENTID(&lock->lk_new_clientid)) {
                        printk("NFSD: nfsd4_lock: clientid is stale!\n");
                        goto out;
                }

                /* is the new lock seqid presented by the client zero? */
                status = nfserr_bad_seqid;
                if (lock->v.new.lock_seqid != 0)
                        goto out;

                /* validate and update open stateid and open seqid */
                status = nfs4_preprocess_seqid_op(current_fh, 
                                        lock->lk_new_open_seqid,
                                        &lock->lk_new_open_stateid,
                                        CHECK_FH | OPEN_STATE,
                                        &open_sop, &open_stp,
                                        &lock->v.new.clientid);
                if (status) {
                        if (lock->lk_reclaim)
                                status = nfserr_reclaim_bad;
                        goto out;
                }
                /* create lockowner and lock stateid */
                fp = open_stp->st_file;
                strhashval = lock_ownerstr_hashval(fp->fi_inode, 
                                open_sop->so_client->cl_clientid.cl_id, 
                                &lock->v.new.owner);
                /* 
                 * If we already have this lock owner, the client is in 
                 * error (or our bookeeping is wrong!) 
                 * for asking for a 'new lock'.
                 */
                status = nfserr_bad_stateid;
                lock_sop = find_lockstateowner(&lock->v.new.owner,
                                                &lock->v.new.clientid);
                if (lock_sop)
                        goto out;
                status = nfserr_resource;
                if (!(lock->lk_stateowner = alloc_init_lock_stateowner(strhashval, open_sop->so_client, open_stp, lock)))
                        goto out;
                if ((lock_stp = alloc_init_lock_stateid(lock->lk_stateowner, 
                                                fp, open_stp)) == NULL) {
                        release_stateowner(lock->lk_stateowner);
                        lock->lk_stateowner = NULL;
                        goto out;
                }
                /* bump the open seqid used to create the lock */
                open_sop->so_seqid++;
        } else {
                /* lock (lock owner + lock stateid) already exists */
                status = nfs4_preprocess_seqid_op(current_fh,
                                       lock->lk_old_lock_seqid, 
                                       &lock->lk_old_lock_stateid, 
                                       CHECK_FH | LOCK_STATE, 
                                       &lock->lk_stateowner, &lock_stp, NULL);
                if (status)
                        goto out;
        }
        /* lock->lk_stateowner and lock_stp have been created or found */
        filp = lock_stp->st_vfs_file;

        if ((status = fh_verify(rqstp, current_fh, S_IFREG, MAY_LOCK))) {
                printk("NFSD: nfsd4_lock: permission denied!\n");
                goto out;
        }

        locks_init_lock(&file_lock);
        switch (lock->lk_type) {
                case NFS4_READ_LT:
                case NFS4_READW_LT:
                        file_lock.fl_type = F_RDLCK;
                break;
                case NFS4_WRITE_LT:
                case NFS4_WRITEW_LT:
                        file_lock.fl_type = F_WRLCK;
                break;
                default:
                        status = nfserr_inval;
                goto out;
        }
        file_lock.fl_owner = (fl_owner_t) lock->lk_stateowner;
        file_lock.fl_pid = current->tgid;
        file_lock.fl_file = filp;
        file_lock.fl_flags = FL_POSIX;

        file_lock.fl_start = lock->lk_offset;
        if ((lock->lk_length == ~(u64)0) || 
                        LOFF_OVERFLOW(lock->lk_offset, lock->lk_length))
                file_lock.fl_end = ~(u64)0;
        else
                file_lock.fl_end = lock->lk_offset + lock->lk_length - 1;
        nfs4_transform_lock_offset(&file_lock);

        /*
        * Try to lock the file in the VFS.
        * Note: locks.c uses the BKL to protect the inode's lock list.
        */

        status = posix_lock_file(filp, &file_lock);
        if (file_lock.fl_ops && file_lock.fl_ops->fl_release_private)
                file_lock.fl_ops->fl_release_private(&file_lock);
        dprintk("NFSD: nfsd4_lock: posix_lock_file status %d\n",status);
        switch (-status) {
        case 0: /* success! */
                update_stateid(&lock_stp->st_stateid);
                memcpy(&lock->lk_resp_stateid, &lock_stp->st_stateid, 
                                sizeof(stateid_t));
                goto out;
        case (EAGAIN):
                goto conflicting_lock;
        case (EDEADLK):
                status = nfserr_deadlock;
        default:        
                dprintk("NFSD: nfsd4_lock: posix_lock_file() failed! status %d\n",status);
                goto out_destroy_new_stateid;
        }

conflicting_lock:
        dprintk("NFSD: nfsd4_lock: conflicting lock found!\n");
        status = nfserr_denied;
        /* XXX There is a race here. Future patch needed to provide 
         * an atomic posix_lock_and_test_file
         */
        if (!(conflock = posix_test_lock(filp, &file_lock))) {
                status = nfserr_serverfault;
                goto out;
        }
        nfs4_set_lock_denied(conflock, &lock->lk_denied);

out_destroy_new_stateid:
        if (lock->lk_is_new) {
                dprintk("NFSD: nfsd4_lock: destroy new stateid!\n");
        /*
        * An error encountered after instantiation of the new
        * stateid has forced us to destroy it.
        */
                if (!seqid_mutating_err(status))
                        open_sop->so_seqid--;

                release_state_owner(lock_stp, LOCK_STATE);
        }
out:
        if (lock->lk_stateowner)
                nfs4_get_stateowner(lock->lk_stateowner);
        nfs4_unlock_state();
        return status;
}

/*
 * LOCKT operation
 */
int
nfsd4_lockt(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lockt *lockt)
{
        struct inode *inode;
        struct file file;
        struct file_lock file_lock;
        struct file_lock *conflicting_lock;
        int status;

        if (nfs4_in_grace())
                return nfserr_grace;

        if (check_lock_length(lockt->lt_offset, lockt->lt_length))
                 return nfserr_inval;

        lockt->lt_stateowner = NULL;
        nfs4_lock_state();

        status = nfserr_stale_clientid;
        if (STALE_CLIENTID(&lockt->lt_clientid)) {
                printk("NFSD: nfsd4_lockt: clientid is stale!\n");
                goto out;
        }

        if ((status = fh_verify(rqstp, current_fh, S_IFREG, 0))) {
                printk("NFSD: nfsd4_lockt: fh_verify() failed!\n");
                if (status == nfserr_symlink)
                        status = nfserr_inval;
                goto out;
        }

        inode = current_fh->fh_dentry->d_inode;
        locks_init_lock(&file_lock);
        switch (lockt->lt_type) {
                case NFS4_READ_LT:
                case NFS4_READW_LT:
                        file_lock.fl_type = F_RDLCK;
                break;
                case NFS4_WRITE_LT:
                case NFS4_WRITEW_LT:
                        file_lock.fl_type = F_WRLCK;
                break;
                default:
                        printk("NFSD: nfs4_lockt: bad lock type!\n");
                        status = nfserr_inval;
                goto out;
        }

        lockt->lt_stateowner = find_lockstateowner_str(inode,
                        &lockt->lt_clientid, &lockt->lt_owner);
        if (lockt->lt_stateowner)
                file_lock.fl_owner = (fl_owner_t)lockt->lt_stateowner;
        file_lock.fl_pid = current->tgid;
        file_lock.fl_flags = FL_POSIX;

        file_lock.fl_start = lockt->lt_offset;
        if ((lockt->lt_length == ~(u64)0) || LOFF_OVERFLOW(lockt->lt_offset, lockt->lt_length))
                file_lock.fl_end = ~(u64)0;
        else
                file_lock.fl_end = lockt->lt_offset + lockt->lt_length - 1;

        nfs4_transform_lock_offset(&file_lock);

        /* posix_test_lock uses the struct file _only_ to resolve the inode.
         * since LOCKT doesn't require an OPEN, and therefore a struct
         * file may not exist, pass posix_test_lock a struct file with
         * only the dentry:inode set.
         */
        memset(&file, 0, sizeof (struct file));
        file.f_dentry = current_fh->fh_dentry;

        status = nfs_ok;
        conflicting_lock = posix_test_lock(&file, &file_lock);
        if (conflicting_lock) {
                status = nfserr_denied;
                nfs4_set_lock_denied(conflicting_lock, &lockt->lt_denied);
        }
out:
        nfs4_unlock_state();
        return status;
}

int
nfsd4_locku(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_locku *locku)
{
        struct nfs4_stateid *stp;
        struct file *filp = NULL;
        struct file_lock file_lock;
        int status;
                                                        
        dprintk("NFSD: nfsd4_locku: start=%Ld length=%Ld\n",
                (long long) locku->lu_offset,
                (long long) locku->lu_length);

        if (check_lock_length(locku->lu_offset, locku->lu_length))
                 return nfserr_inval;

        nfs4_lock_state();
                                                                                
        if ((status = nfs4_preprocess_seqid_op(current_fh, 
                                        locku->lu_seqid, 
                                        &locku->lu_stateid, 
                                        CHECK_FH | LOCK_STATE, 
                                        &locku->lu_stateowner, &stp, NULL)))
                goto out;

        filp = stp->st_vfs_file;
        BUG_ON(!filp);
        locks_init_lock(&file_lock);
        file_lock.fl_type = F_UNLCK;
        file_lock.fl_owner = (fl_owner_t) locku->lu_stateowner;
        file_lock.fl_pid = current->tgid;
        file_lock.fl_file = filp;
        file_lock.fl_flags = FL_POSIX; 
        file_lock.fl_start = locku->lu_offset;

        if ((locku->lu_length == ~(u64)0) || LOFF_OVERFLOW(locku->lu_offset, locku->lu_length))
                file_lock.fl_end = ~(u64)0;
        else
                file_lock.fl_end = locku->lu_offset + locku->lu_length - 1;
        nfs4_transform_lock_offset(&file_lock);

        /*
        *  Try to unlock the file in the VFS.
        */
        status = posix_lock_file(filp, &file_lock); 
        if (file_lock.fl_ops && file_lock.fl_ops->fl_release_private)
                file_lock.fl_ops->fl_release_private(&file_lock);
        if (status) {
                printk("NFSD: nfs4_locku: posix_lock_file failed!\n");
                goto out_nfserr;
        }
        /*
        * OK, unlock succeeded; the only thing left to do is update the stateid.
        */
        update_stateid(&stp->st_stateid);
        memcpy(&locku->lu_stateid, &stp->st_stateid, sizeof(stateid_t));

out:
        if (locku->lu_stateowner)
                nfs4_get_stateowner(locku->lu_stateowner);
        nfs4_unlock_state();
        return status;

out_nfserr:
        status = nfserrno(status);
        goto out;
}

/*
 * returns
 *      1: locks held by lockowner
 *      0: no locks held by lockowner
 */
static int
check_for_locks(struct file *filp, struct nfs4_stateowner *lowner)
{
        struct file_lock **flpp;
        struct inode *inode = filp->f_dentry->d_inode;
        int status = 0;

        lock_kernel();
        for (flpp = &inode->i_flock; *flpp != NULL; flpp = &(*flpp)->fl_next) {
                if ((*flpp)->fl_owner == (fl_owner_t)lowner)
                        status = 1;
                        goto out;
        }
out:
        unlock_kernel();
        return status;
}

int
nfsd4_release_lockowner(struct svc_rqst *rqstp, struct nfsd4_release_lockowner *rlockowner)
{
        clientid_t *clid = &rlockowner->rl_clientid;
        struct nfs4_stateowner *local = NULL;
        struct xdr_netobj *owner = &rlockowner->rl_owner;
        int status;

        dprintk("nfsd4_release_lockowner clientid: (%08x/%08x):\n",
                clid->cl_boot, clid->cl_id);

        /* XXX check for lease expiration */

        status = nfserr_stale_clientid;
        if (STALE_CLIENTID(clid)) {
                printk("NFSD: nfsd4_release_lockowner: clientid is stale!\n");
                return status;
        }

        nfs4_lock_state();

        status = nfs_ok;
        local = find_lockstateowner(owner, clid);
        if (local) {
                struct nfs4_stateid *stp;

                /* check for any locks held by any stateid
                 * associated with the (lock) stateowner */
                status = nfserr_locks_held;
                list_for_each_entry(stp, &local->so_perfilestate,
                                st_perfilestate) {
                        if (check_for_locks(stp->st_vfs_file, local))
                                goto out;
                }
                /* no locks held by (lock) stateowner */
                status = nfs_ok;
                release_stateowner(local);
        }
out:
        nfs4_unlock_state();
        return status;
}

static inline struct nfs4_client_reclaim *
alloc_reclaim(int namelen)
{
        struct nfs4_client_reclaim *crp = NULL;

        crp = kmalloc(sizeof(struct nfs4_client_reclaim), GFP_KERNEL);
        if (!crp)
                return NULL;
        crp->cr_name.data = kmalloc(namelen, GFP_KERNEL);
        if (!crp->cr_name.data) {
                kfree(crp);
                return NULL;
        }
        return crp;
}

/*
 * failure => all reset bets are off, nfserr_no_grace...
 */
static int
nfs4_client_to_reclaim(char *name, int namlen)
{
        unsigned int strhashval;
        struct nfs4_client_reclaim *crp = NULL;

        dprintk("NFSD nfs4_client_to_reclaim NAME: %.*s\n", namlen, name);
        crp = alloc_reclaim(namlen);
        if (!crp)
                return 0;
        strhashval = clientstr_hashval(name, namlen);
        INIT_LIST_HEAD(&crp->cr_strhash);
        list_add(&crp->cr_strhash, &reclaim_str_hashtbl[strhashval]);
        memcpy(crp->cr_name.data, name, namlen);
        crp->cr_name.len = namlen;
        reclaim_str_hashtbl_size++;
        return 1;
}

static void
nfs4_release_reclaim(void)
{
        struct nfs4_client_reclaim *crp = NULL;
        int i;

        for (i = 0; i < CLIENT_HASH_SIZE; i++) {
                while (!list_empty(&reclaim_str_hashtbl[i])) {
                        crp = list_entry(reclaim_str_hashtbl[i].next,
                                        struct nfs4_client_reclaim, cr_strhash);
                        list_del(&crp->cr_strhash);
                        kfree(crp->cr_name.data);
                        kfree(crp);
                        reclaim_str_hashtbl_size--;
                }
        }
        BUG_ON(reclaim_str_hashtbl_size);
}

/*
 * called from OPEN, CLAIM_PREVIOUS with a new clientid. */
struct nfs4_client_reclaim *
nfs4_find_reclaim_client(clientid_t *clid)
{
        unsigned int strhashval;
        struct nfs4_client *clp;
        struct nfs4_client_reclaim *crp = NULL;


        /* find clientid in conf_id_hashtbl */
        clp = find_confirmed_client(clid);
        if (clp == NULL)
                return NULL;

        dprintk("NFSD: nfs4_find_reclaim_client for %.*s\n",
                            clp->cl_name.len, clp->cl_name.data);

        /* find clp->cl_name in reclaim_str_hashtbl */
        strhashval = clientstr_hashval(clp->cl_name.data, clp->cl_name.len);
        list_for_each_entry(crp, &reclaim_str_hashtbl[strhashval], cr_strhash) {
                if (cmp_name(&crp->cr_name, &clp->cl_name)) {
                        return crp;
                }
        }
        return NULL;
}

/*
* Called from OPEN. Look for clientid in reclaim list.
*/
int
nfs4_check_open_reclaim(clientid_t *clid)
{
        return nfs4_find_reclaim_client(clid) ? nfs_ok : nfserr_reclaim_bad;
}

/* initialization to perform at module load time: */

void
nfs4_state_init(void)
{
        int i;

        for (i = 0; i < CLIENT_HASH_SIZE; i++) {
                INIT_LIST_HEAD(&conf_id_hashtbl[i]);
                INIT_LIST_HEAD(&conf_str_hashtbl[i]);
                INIT_LIST_HEAD(&unconf_str_hashtbl[i]);
                INIT_LIST_HEAD(&unconf_id_hashtbl[i]);
        }
        for (i = 0; i < FILE_HASH_SIZE; i++) {
                INIT_LIST_HEAD(&file_hashtbl[i]);
        }
        for (i = 0; i < OWNER_HASH_SIZE; i++) {
                INIT_LIST_HEAD(&ownerstr_hashtbl[i]);
                INIT_LIST_HEAD(&ownerid_hashtbl[i]);
        }
        for (i = 0; i < STATEID_HASH_SIZE; i++) {
                INIT_LIST_HEAD(&stateid_hashtbl[i]);
                INIT_LIST_HEAD(&lockstateid_hashtbl[i]);
        }
        for (i = 0; i < LOCK_HASH_SIZE; i++) {
                INIT_LIST_HEAD(&lock_ownerid_hashtbl[i]);
                INIT_LIST_HEAD(&lock_ownerstr_hashtbl[i]);
        }
        memset(&onestateid, ~0, sizeof(stateid_t));
        INIT_LIST_HEAD(&close_lru);
        INIT_LIST_HEAD(&client_lru);
        INIT_LIST_HEAD(&del_recall_lru);
        for (i = 0; i < CLIENT_HASH_SIZE; i++)
                INIT_LIST_HEAD(&reclaim_str_hashtbl[i]);
        reclaim_str_hashtbl_size = 0;
}

/* initialization to perform when the nfsd service is started: */

static void
__nfs4_state_start(void)
{
        time_t grace_time;

        boot_time = get_seconds();
        grace_time = max(user_lease_time, lease_time);
        lease_time = user_lease_time;
        printk("NFSD: starting %ld-second grace period\n", grace_time);
        grace_end = boot_time + grace_time;
        laundry_wq = create_singlethread_workqueue("nfsd4");
        queue_delayed_work(laundry_wq, &laundromat_work, NFSD_LEASE_TIME*HZ);
}

int
nfs4_state_start(void)
{
        int status;

        if (nfs4_init)
                return 0;
        status = nfsd4_init_slabs();
        if (status)
                return status;
        __nfs4_state_start();
        nfs4_init = 1;
        return 0;
}

int
nfs4_in_grace(void)
{
        return get_seconds() < grace_end;
}

void
set_no_grace(void)
{
        printk("NFSD: ERROR in reboot recovery.  State reclaims will fail.\n");
        grace_end = get_seconds();
}

time_t
nfs4_lease_time(void)
{
        return lease_time;
}

static void
__nfs4_state_shutdown(void)
{
        int i;
        struct nfs4_client *clp = NULL;
        struct nfs4_delegation *dp = NULL;
        struct nfs4_stateowner *sop = NULL;
        struct list_head *pos, *next, reaplist;

        list_for_each_safe(pos, next, &close_lru) {
                sop = list_entry(pos, struct nfs4_stateowner, so_close_lru);
                list_del(&sop->so_close_lru);
                nfs4_put_stateowner(sop);
        }

        for (i = 0; i < CLIENT_HASH_SIZE; i++) {
                while (!list_empty(&conf_id_hashtbl[i])) {
                        clp = list_entry(conf_id_hashtbl[i].next, struct nfs4_client, cl_idhash);
                        expire_client(clp);
                }
                while (!list_empty(&unconf_str_hashtbl[i])) {
                        clp = list_entry(unconf_str_hashtbl[i].next, struct nfs4_client, cl_strhash);
                        expire_client(clp);
                }
        }
        INIT_LIST_HEAD(&reaplist);
        spin_lock(&recall_lock);
        list_for_each_safe(pos, next, &del_recall_lru) {
                dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
                list_move(&dp->dl_recall_lru, &reaplist);
        }
        spin_unlock(&recall_lock);
        list_for_each_safe(pos, next, &reaplist) {
                dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
                list_del_init(&dp->dl_recall_lru);
                unhash_delegation(dp);
        }

        cancel_delayed_work(&laundromat_work);
        flush_workqueue(laundry_wq);
        destroy_workqueue(laundry_wq);
        nfs4_init = 0;
}

void
nfs4_state_shutdown(void)
{
        nfs4_lock_state();
        nfs4_release_reclaim();
        __nfs4_state_shutdown();
        nfsd4_free_slabs();
        nfs4_unlock_state();
}

/*
 * Called when leasetime is changed.
 *
 * The only way the protocol gives us to handle on-the-fly lease changes is to
 * simulate a reboot.  Instead of doing that, we just wait till the next time
 * we start to register any changes in lease time.  If the administrator
 * really wants to change the lease time *now*, they can go ahead and bring
 * nfsd down and then back up again after changing the lease time.
 */
void
nfs4_reset_lease(time_t leasetime)
{
        lock_kernel();
        user_lease_time = leasetime;
        unlock_kernel();
}