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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>
#include <linux/namei.h>
#include <linux/mutex.h>

#define NFSDDBG_FACILITY                NFSDDBG_PROC

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

#define ZERO_STATEID(stateid) (!memcmp((stateid), &zerostateid, sizeof(stateid_t)))
#define ONE_STATEID(stateid)  (!memcmp((stateid), &onestateid, sizeof(stateid_t)))

/* forward declarations */
static 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);
static char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
static void nfs4_set_recdir(char *recdir);

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

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

void
nfs4_lock_state(void)
{
      mutex_lock(&client_mutex);
}

void
nfs4_unlock_state(void)
{
      mutex_unlock(&client_mutex);
}

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 */
static DEFINE_SPINLOCK(recall_lock);
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 int num_delegations;

/*
 * 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];

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");
      if (num_delegations > STATEID_HASH_SIZE * 4)
            return NULL;
      dp = kmem_cache_alloc(deleg_slab, GFP_KERNEL);
      if (dp == NULL)
            return dp;
      num_delegations++;
      INIT_LIST_HEAD(&dp->dl_perfile);
      INIT_LIST_HEAD(&dp->dl_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_perfile, &fp->fi_delegations);
      list_add(&dp->dl_perclnt, &clp->cl_delegations);
      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);
            num_delegations--;
      }
}

/* 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_perfile);
      list_del_init(&dp->dl_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) \
      (opaque_hashval((name), 8) & 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
shutdown_callback_client(struct nfs4_client *clp)
{
      struct rpc_clnt *clnt = clp->cl_callback.cb_client;

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

static void
expire_client(struct nfs4_client *clp)
{
      struct nfs4_stateowner *sop;
      struct nfs4_delegation *dp;
      struct list_head reaplist;

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

      shutdown_callback_client(clp);

      INIT_LIST_HEAD(&reaplist);
      spin_lock(&recall_lock);
      while (!list_empty(&clp->cl_delegations)) {
            dp = list_entry(clp->cl_delegations.next, struct nfs4_delegation, dl_perclnt);
            dprintk("NFSD: expire client. dp %p, fp %p\n", dp,
                        dp->dl_flock);
            list_del_init(&dp->dl_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_openowners)) {
            sop = list_entry(clp->cl_openowners.next, struct nfs4_stateowner, so_perclient);
            release_stateowner(sop);
      }
      put_nfs4_client(clp);
}

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

      if (!(clp = alloc_client(name)))
            goto out;
      memcpy(clp->cl_recdir, recdir, HEXDIR_LEN);
      atomic_set(&clp->cl_count, 1);
      atomic_set(&clp->cl_callback.cb_set, 0);
      INIT_LIST_HEAD(&clp->cl_idhash);
      INIT_LIST_HEAD(&clp->cl_strhash);
      INIT_LIST_HEAD(&clp->cl_openowners);
      INIT_LIST_HEAD(&clp->cl_delegations);
      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 inline int
same_name(const char *n1, const char *n2) {
      return 0 == memcmp(n1, n2, HEXDIR_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;
}

static 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();
}

static 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_move(&clp->cl_idhash, &conf_id_hashtbl[idhashval]);
      strhashval = clientstr_hashval(clp->cl_recdir);
      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;
}

static struct nfs4_client *
find_confirmed_client_by_str(const char *dname, unsigned int hashval)
{
      struct nfs4_client *clp;

      list_for_each_entry(clp, &conf_str_hashtbl[hashval], cl_strhash) {
            if (same_name(clp->cl_recdir, dname))
                  return clp;
      }
      return NULL;
}

static struct nfs4_client *
find_unconfirmed_client_by_str(const char *dname, unsigned int hashval)
{
      struct nfs4_client *clp;

      list_for_each_entry(clp, &unconf_str_hashtbl[hashval], cl_strhash) {
            if (same_name(clp->cl_recdir, dname))
                  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 */
static 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;
}

static 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;
      return;
out_err:
      dprintk(KERN_INFO "NFSD: this client (clientid %08x/%08x) "
            "will not receive delegations\n",
            clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);

      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;
      int               status;
      char                    dname[HEXDIR_LEN];
      
      if (!check_name(clname))
            return nfserr_inval;

      status = nfs4_make_rec_clidname(dname, &clname);
      if (status)
            return status;

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

      strhashval = clientstr_hashval(dname);

      nfs4_lock_state();
      conf = find_confirmed_client_by_str(dname, strhashval);
      if (conf) {
            /* 
             * CASE 0:
             * clname match, confirmed, different principal
             * or different ip_address
             */
            status = nfserr_clid_inuse;
            if (!cmp_creds(&conf->cl_cred, &rqstp->rq_cred)
                        || conf->cl_addr != ip_addr) {
                  printk("NFSD: setclientid: string in use by client"
                  "(clientid %08x/%08x)\n",
                  conf->cl_clientid.cl_boot, conf->cl_clientid.cl_id);
                  goto out;
            }
      }
      unconf = find_unconfirmed_client_by_str(dname, strhashval);
      status = nfserr_resource;
      if (!conf) {
            /* 
             * CASE 4:
             * placed first, because it is the normal case.
             */
            if (unconf)
                  expire_client(unconf);
            new = create_client(clname, dname);
            if (new == NULL)
                  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) {
                  /* Note this is removing unconfirmed {*x***},
                   * which is stronger than RFC recommended {vxc**}.
                   * This has the advantage that there is at most
                   * one {*x***} in either list at any time.
                   */
                  expire_client(unconf);
            }
            new = create_client(clname, dname);
            if (new == NULL)
                  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.
             */
            new = create_client(clname, dname);
            if (new == NULL)
                  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);
            new = create_client(clname, dname);
            if (new == NULL)
                  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 *conf, *unconf;
      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();

      conf = find_confirmed_client(clid);
      unconf = find_unconfirmed_client(clid);

      status = nfserr_clid_inuse;
      if (conf && conf->cl_addr != ip_addr)
            goto out;
      if (unconf && unconf->cl_addr != ip_addr)
            goto out;

      if ((conf && unconf) && 
          (cmp_verf(&unconf->cl_confirm, &confirm)) &&
          (cmp_verf(&conf->cl_verifier, &unconf->cl_verifier)) &&
          (same_name(conf->cl_recdir,unconf->cl_recdir))  &&
          (!cmp_verf(&conf->cl_confirm, &unconf->cl_confirm))) {
            /* 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 (!cmp_creds(&conf->cl_cred, &unconf->cl_cred)) 
                  status = nfserr_clid_inuse;
            else {
                  /* XXX: We just turn off callbacks until we can handle
                    * change request correctly. */
                  atomic_set(&conf->cl_callback.cb_set, 0);
                  gen_confirm(conf);
                  nfsd4_remove_clid_dir(unconf);
                  expire_client(unconf);
                  status = nfs_ok;

            }
      } else if ((conf && !unconf) ||
          ((conf && unconf) && 
           (!cmp_verf(&conf->cl_verifier, &unconf->cl_verifier) ||
            !same_name(conf->cl_recdir, unconf->cl_recdir)))) {
            /* CASE 2:
             * conf record that matches input clientid.
             * if unconf record matches input clientid, then
             * unconf->cl_name or unconf->cl_verifier don't match the
             * conf record.
             */
            if (!cmp_creds(&conf->cl_cred,&rqstp->rq_cred))
                  status = nfserr_clid_inuse;
            else
                  status = nfs_ok;
      } else if (!conf && unconf
                  && cmp_verf(&unconf->cl_confirm, &confirm)) {
            /* CASE 3:
             * conf record not found.
             * unconf record found.
             * unconf->cl_confirm matches input confirm
             */
            if (!cmp_creds(&unconf->cl_cred, &rqstp->rq_cred)) {
                  status = nfserr_clid_inuse;
            } else {
                  unsigned int hash =
                        clientstr_hashval(unconf->cl_recdir);
                  conf = find_confirmed_client_by_str(unconf->cl_recdir,
                                                      hash);
                  if (conf) {
                        nfsd4_remove_clid_dir(conf);
                        expire_client(conf);
                  }
                  move_to_confirmed(unconf);
                  conf = unconf;
                  status = nfs_ok;
            }
      } else if ((!conf || (conf && !cmp_verf(&conf->cl_confirm, &confirm)))
          && (!unconf || (unconf && !cmp_verf(&unconf->cl_confirm,
                                                &confirm)))) {
            /* CASE 4:
             * conf record not found, or if conf, conf->cl_confirm does not
             * match input confirm.
             * unconf record not found, or if unconf, unconf->cl_confirm
             * does not match input confirm.
             */
            status = nfserr_stale_clientid;
      } else {
            /* check that we have hit one of the cases...*/
            status = nfserr_clid_inuse;
      }
out:
      if (!status)
            nfsd4_probe_callback(conf);
      nfs4_unlock_state();
      return status;
}

/* 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_stateids);
      INIT_LIST_HEAD(&sop->so_perstateid);  /* 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_openowners);
      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_lockowners)) {
            lock_sop = list_entry(open_stp->st_lockowners.next,
                        struct nfs4_stateowner, so_perstateid);
            /* list_del(&open_stp->st_lockowners);  */
            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_perstateid);
      while (!list_empty(&sop->so_stateids)) {
            stp = list_entry(sop->so_stateids.next,
                  struct nfs4_stateid, st_perstateowner);
            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_perstateowner);
      INIT_LIST_HEAD(&stp->st_lockowners);
      INIT_LIST_HEAD(&stp->st_perfile);
      list_add(&stp->st_hash, &stateid_hashtbl[hashval]);
      list_add(&stp->st_perstateowner, &sop->so_stateids);
      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);
      stp->st_openstp = NULL;
}

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_perstateowner);
      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);
}

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

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

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;
}

static int access_valid(u32 x)
{
      return (x > 0 && x < 4);
}

static int deny_valid(u32 x)
{
      return (x >= 0 && x < 5);
}

static 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;
      }
}

static 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
 */
static 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_locked;
      /* 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;
}

static 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,
};


int
nfsd4_process_open1(struct nfsd4_open *open)
{
      clientid_t *clientid = &open->op_clientid;
      struct nfs4_client *clp = NULL;
      unsigned int strhashval;
      struct nfs4_stateowner *sop = NULL;

      if (!check_name(open->op_owner))
            return nfserr_inval;

      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);
      open->op_stateowner = sop;
      if (!sop) {
            /* Make sure the client's lease hasn't expired. */
            clp = find_confirmed_client(clientid);
            if (clp == NULL)
                  return nfserr_expired;
            goto renew;
      }
      if (!sop->so_confirmed) {
            /* Replace unconfirmed owners without checking for replay. */
            clp = sop->so_client;
            release_stateowner(sop);
            open->op_stateowner = NULL;
            goto renew;
      }
      if (open->op_seqid == sop->so_seqid - 1) {
            if (sop->so_replay.rp_buflen)
                  return NFSERR_REPLAY_ME;
            /* 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;
      }
      if (open->op_seqid != sop->so_seqid)
            return nfserr_bad_seqid;
renew:
      if (open->op_stateowner == NULL) {
            sop = alloc_init_open_stateowner(strhashval, clp, open);
            if (sop == NULL)
                  return nfserr_resource;
            open->op_stateowner = sop;
      }
      list_del_init(&sop->so_close_lru);
      renew_client(sop->so_client);
      return nfs_ok;
}

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_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 nfserr_inval;
      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, new_writer;
      int status;

      set_access(&share_access, stp->st_access_bmap);
      new_writer = (~share_access) & open->op_share_access
                  & NFS4_SHARE_ACCESS_WRITE;

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

      return nfs_ok;
}


static void
nfs4_set_claim_prev(struct nfsd4_open *open)
{
      open->op_stateowner->so_confirmed = 1;
      open->op_stateowner->so_client->cl_firststate = 1;
}

/*
 * 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 (!access_valid(open->op_share_access)
                  || !deny_valid(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;
            update_stateid(&stp->st_stateid);
      } else {
            /* Stateid was not found, this is a new OPEN */
            int flags = 0;
            if (open->op_share_access & NFS4_SHARE_ACCESS_READ)
                  flags |= MAY_READ;
            if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
                  flags |= MAY_WRITE;
            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);
      if (status == 0 && open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS)
            nfs4_set_claim_prev(open);
      /*
      * 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_delegations)
                  && !atomic_read(&clp->cl_callback.cb_set))
            goto out;
      status = nfs_ok;
out:
      nfs4_unlock_state();
      return status;
}

static void
end_grace(void)
{
      dprintk("NFSD: end of grace period\n");
      nfsd4_recdir_purge_old();
      in_grace = 0;
}

static 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");
      if (in_grace)
            end_grace();
      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);
            nfsd4_remove_clid_dir(clp);
            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);
            release_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);
}

static struct nfs4_stateowner *
search_close_lru(u32 st_id, int flags)
{
      struct nfs4_stateowner *local = NULL;

      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;
      dprintk("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");
                  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");
                  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;
}

static inline int
setlkflg (int type)
{
      return (type == NFS4_READW_LT || type == NFS4_READ_LT) ?
            RD_STATE : WR_STATE;
}

/* 
 * Checks for sequence id mutating operations. 
 */
static 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, struct nfsd4_lock *lock)
{
      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;

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

      if (STALE_STATEID(stateid))
            return nfserr_stale_stateid;
      /*
      * We return BAD_STATEID if filehandle doesn't match stateid, 
      * the confirmed flag is incorrecly set, or the generation 
      * number is incorrect.  
      */
      stp = find_stateid(stateid, flags);
      if (stp == NULL) {
            /*
             * Also, we should make sure this isn't just the result of
             * a replayed close:
             */
            sop = search_close_lru(stateid->si_stateownerid, flags);
            if (sop == NULL)
                  return nfserr_bad_stateid;
            *sopp = sop;
            goto check_replay;
      }

      if (lock) {
            struct nfs4_stateowner *sop = stp->st_stateowner;
            clientid_t *lockclid = &lock->v.new.clientid;
            struct nfs4_client *clp = sop->so_client;
            int lkflg = 0;
            int status;

            lkflg = setlkflg(lock->lk_type);

            if (lock->lk_is_new) {
                       if (!sop->so_is_open_owner)
                         return nfserr_bad_stateid;
                       if (!cmp_clid(&clp->cl_clientid, lockclid))
                         return nfserr_bad_stateid;
                       /* stp is the open stateid */
                       status = nfs4_check_openmode(stp, lkflg);
                       if (status)
                         return status;
               } else {
                       /* stp is the lock stateid */
                       status = nfs4_check_openmode(stp->st_openstp, lkflg);
                       if (status)
                         return status;
               }

      }

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

      *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)
            goto check_replay;

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

      if (stateid->si_generation < stp->st_stateid.si_generation) {
            printk("NFSD: preprocess_seqid_op: old stateid!\n");
            return nfserr_old_stateid;
      }
      renew_client(sop->so_client);
      return nfs_ok;

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

int
nfsd4_open_confirm(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open_confirm *oc, struct nfs4_stateowner **replay_owner)
{
      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);

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

      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);

      nfsd4_create_clid_dir(sop->so_client);
out:
      if (oc->oc_stateowner) {
            nfs4_get_stateowner(oc->oc_stateowner);
            *replay_owner = 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, struct nfs4_stateowner **replay_owner)
{
      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 (!access_valid(od->od_share_access)
                  || !deny_valid(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);
            *replay_owner = 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, struct nfs4_stateowner **replay_owner)
{
      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; 
      status = nfs_ok;
      update_stateid(&stp->st_stateid);
      memcpy(&close->cl_stateid, &stp->st_stateid, sizeof(stateid_t));

      /* release_stateid() calls nfsd_close() if needed */
      release_stateid(stp, OPEN_STATE);

      /* 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 (list_empty(&close->cl_stateowner->so_stateids))
            move_to_close_lru(close->cl_stateowner);
out:
      if (close->cl_stateowner) {
            nfs4_get_stateowner(close->cl_stateowner);
            *replay_owner = 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];

static 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;
            }
      }
      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;
}

/* Hack!: For now, we're defining this just so we can use a pointer to it
 * as a unique cookie to identify our (NFSv4's) posix locks. */
static struct lock_manager_operations nfsd_posix_mng_ops  = {
};

static inline void
nfs4_set_lock_denied(struct file_lock *fl, struct nfsd4_lock_denied *deny)
{
      struct nfs4_stateowner *sop;
      unsigned int hval;

      if (fl->fl_lmops == &nfsd_posix_mng_ops) {
            sop = (struct nfs4_stateowner *) fl->fl_owner;
            hval = lockownerid_hashval(sop->so_id);
            kref_get(&sop->so_ref);
            deny->ld_sop = sop;
            deny->ld_clientid = sop->so_client->cl_clientid;
      } else {
            deny->ld_sop = NULL;
            deny->ld_clientid.cl_boot = 0;
            deny->ld_clientid.cl_id = 0;
      }
      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_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 
 */

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_stateids);
      INIT_LIST_HEAD(&sop->so_perstateid);
      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_perstateid, &open_stp->st_lockowners);
      sop->so_is_open_owner = 0;
      sop->so_id = current_ownerid++;
      sop->so_client = clp;
      /* It is the openowner seqid that will be incremented in encode in the
       * case of new lockowners; so increment the lock seqid manually: */
      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;
}

static 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_perstateowner);
      INIT_LIST_HEAD(&stp->st_lockowners); /* not used */
      list_add(&stp->st_hash, &lockstateid_hashtbl[hashval]);
      list_add(&stp->st_perfile, &fp->fi_stateids);
      list_add(&stp->st_perstateowner, &sop->so_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_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;
      stp->st_openstp = open_stp;

out:
      return stp;
}

static 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 **replay_owner)
{
      struct nfs4_stateowner *open_sop = NULL;
      struct nfs4_stateowner *lock_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 (check_lock_length(lock->lk_offset, lock->lk_length))
             return nfserr_inval;

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

      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))
                  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,
                                    &lock->lk_replay_owner, &open_stp,
                              lock);
            if (status)
                  goto out;
            open_sop = lock->lk_replay_owner;
            /* 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);
            /* XXX: Do we need to check for duplicate stateowners on
             * the same file, or should they just be allowed (and
             * create new stateids)? */
            status = nfserr_resource;
            lock_sop = alloc_init_lock_stateowner(strhashval,
                        open_sop->so_client, open_stp, lock);
            if (lock_sop == NULL)
                  goto out;
            lock_stp = alloc_init_lock_stateid(lock_sop, fp, open_stp);
            if (lock_stp == NULL)
                  goto out;
      } 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_replay_owner, &lock_stp, lock);
            if (status)
                  goto out;
            lock_sop = lock->lk_replay_owner;
      }
      /* lock->lk_replay_owner and lock_stp have been created or found */
      filp = lock_stp->st_vfs_file;

      status = nfserr_grace;
      if (nfs4_in_grace() && !lock->lk_reclaim)
            goto out;
      status = nfserr_no_grace;
      if (!nfs4_in_grace() && lock->lk_reclaim)
            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_sop;
      file_lock.fl_pid = current->tgid;
      file_lock.fl_file = filp;
      file_lock.fl_flags = FL_POSIX;
      file_lock.fl_lmops = &nfsd_posix_mng_ops;

      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.
      */

      /* XXX?: Just to divert the locks_release_private at the start of
       * locks_copy_lock: */
      conflock.fl_ops = NULL;
      conflock.fl_lmops = NULL;
      status = posix_lock_file_conf(filp, &file_lock, &conflock);
      dprintk("NFSD: nfsd4_lock: posix_lock_file_conf 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));
            break;
      case (EAGAIN):          /* conflock holds conflicting lock */
            status = nfserr_denied;
            dprintk("NFSD: nfsd4_lock: conflicting lock found!\n");
            nfs4_set_lock_denied(&conflock, &lock->lk_denied);
            break;
      case (EDEADLK):
            status = nfserr_deadlock;
            break;
      default:        
            dprintk("NFSD: nfsd4_lock: posix_lock_file_conf() failed! status %d\n",status);
            status = nfserr_resource;
            break;
      }
out:
      if (status && lock->lk_is_new && lock_sop)
            release_stateowner(lock_sop);
      if (lock->lk_replay_owner) {
            nfs4_get_stateowner(lock->lk_replay_owner);
            *replay_owner = lock->lk_replay_owner;
      }
      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 conflock;
      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))
            goto out;

      if ((status = fh_verify(rqstp, current_fh, S_IFREG, 0))) {
            dprintk("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_lmops = &nfsd_posix_mng_ops;

      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;
      if (posix_test_lock(&file, &file_lock, &conflock)) {
            status = nfserr_denied;
            nfs4_set_lock_denied(&conflock, &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_stateowner **replay_owner)
{
      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_lmops = &nfsd_posix_mng_ops;
      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 (status) {
            dprintk("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);
            *replay_owner = 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 *sop;
      struct nfs4_stateid *stp;
      struct xdr_netobj *owner = &rlockowner->rl_owner;
      struct list_head matches;
      int i;
      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))
            return status;

      nfs4_lock_state();

      status = nfserr_locks_held;
      /* XXX: we're doing a linear search through all the lockowners.
       * Yipes!  For now we'll just hope clients aren't really using
       * release_lockowner much, but eventually we have to fix these
       * data structures. */
      INIT_LIST_HEAD(&matches);
      for (i = 0; i < LOCK_HASH_SIZE; i++) {
            list_for_each_entry(sop, &lock_ownerid_hashtbl[i], so_idhash) {
                  if (!cmp_owner_str(sop, owner, clid))
                        continue;
                  list_for_each_entry(stp, &sop->so_stateids,
                              st_perstateowner) {
                        if (check_for_locks(stp->st_vfs_file, sop))
                              goto out;
                        /* Note: so_perclient unused for lockowners,
                         * so it's OK to fool with here. */
                        list_add(&sop->so_perclient, &matches);
                  }
            }
      }
      /* Clients probably won't expect us to return with some (but not all)
       * of the lockowner state released; so don't release any until all
       * have been checked. */
      status = nfs_ok;
      while (!list_empty(&matches)) {
            sop = list_entry(matches.next, struct nfs4_stateowner,
                                                so_perclient);
            /* unhash_stateowner deletes so_perclient only
             * for openowners. */
            list_del(&sop->so_perclient);
            release_stateowner(sop);
      }
out:
      nfs4_unlock_state();
      return status;
}

static inline struct nfs4_client_reclaim *
alloc_reclaim(void)
{
      return kmalloc(sizeof(struct nfs4_client_reclaim), GFP_KERNEL);
}

int
nfs4_has_reclaimed_state(const char *name)
{
      unsigned int strhashval = clientstr_hashval(name);
      struct nfs4_client *clp;

      clp = find_confirmed_client_by_str(name, strhashval);
      return clp ? 1 : 0;
}

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

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

/*
 * called from OPEN, CLAIM_PREVIOUS with a new clientid. */
static 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 with recdir %s\n",
                        clp->cl_name.len, clp->cl_name.data,
                      clp->cl_recdir);

      /* find clp->cl_name in reclaim_str_hashtbl */
      strhashval = clientstr_hashval(clp->cl_recdir);
      list_for_each_entry(crp, &reclaim_str_hashtbl[strhashval], cr_strhash) {
            if (same_name(crp->cr_recdir, clp->cl_recdir)) {
                  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;
}

static void
nfsd4_load_reboot_recovery_data(void)
{
      int status;

      nfs4_lock_state();
      nfsd4_init_recdir(user_recovery_dirname);
      status = nfsd4_recdir_load();
      nfs4_unlock_state();
      if (status)
            printk("NFSD: Failure reading reboot recovery data\n");
}

/* 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;
      in_grace = 1;
      printk("NFSD: starting %ld-second grace period\n", grace_time);
      laundry_wq = create_singlethread_workqueue("nfsd4");
      queue_delayed_work(laundry_wq, &laundromat_work, grace_time*HZ);
}

int
nfs4_state_start(void)
{
      int status;

      if (nfs4_init)
            return 0;
      status = nfsd4_init_slabs();
      if (status)
            return status;
      nfsd4_load_reboot_recovery_data();
      __nfs4_state_start();
      nfs4_init = 1;
      return 0;
}

int
nfs4_in_grace(void)
{
      return in_grace;
}

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 list_head *pos, *next, reaplist;

      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);
      nfsd4_shutdown_recdir();
      nfs4_init = 0;
}

void
nfs4_state_shutdown(void)
{
      cancel_rearming_delayed_workqueue(laundry_wq, &laundromat_work);
      destroy_workqueue(laundry_wq);
      nfs4_lock_state();
      nfs4_release_reclaim();
      __nfs4_state_shutdown();
      nfsd4_free_slabs();
      nfs4_unlock_state();
}

static void
nfs4_set_recdir(char *recdir)
{
      nfs4_lock_state();
      strcpy(user_recovery_dirname, recdir);
      nfs4_unlock_state();
}

/*
 * Change the NFSv4 recovery directory to recdir.
 */
int
nfs4_reset_recoverydir(char *recdir)
{
      int status;
      struct nameidata nd;

      status = path_lookup(recdir, LOOKUP_FOLLOW, &nd);
      if (status)
            return status;
      status = -ENOTDIR;
      if (S_ISDIR(nd.dentry->d_inode->i_mode)) {
            nfs4_set_recdir(recdir);
            status = 0;
      }
      path_release(&nd);
      return status;
}

/*
 * 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();
}

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