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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/file.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/swap.h>
#include <linux/mutex.h>
#include <linux/lockd/bind.h>
#include <linux/module.h>
#include <linux/sunrpc/svcauth_gss.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 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 */
static u64 current_sessionid = 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 char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
static void nfs4_set_recdir(char *recdir);

/* Locking: */

/* Currently used for almost all code touching nfsv4 state: */
static DEFINE_MUTEX(client_mutex);

/*
 * Currently used for the del_recall_lru and file hash table.  In an
 * effort to decrease the scope of the client_mutex, this spinlock may
 * eventually cover more:
 */
static DEFINE_SPINLOCK(recall_lock);

static struct kmem_cache *stateowner_slab = NULL;
static struct kmem_cache *file_slab = NULL;
static struct kmem_cache *stateid_slab = NULL;
static struct kmem_cache *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;
}

static struct list_head del_recall_lru;

static inline void
put_nfs4_file(struct nfs4_file *fi)
{
      if (atomic_dec_and_lock(&fi->fi_ref, &recall_lock)) {
            list_del(&fi->fi_hash);
            spin_unlock(&recall_lock);
            iput(fi->fi_inode);
            kmem_cache_free(file_slab, fi);
      }
}

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

static int num_delegations;
unsigned int max_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_cb_conn *cb = &stp->st_stateowner->so_client->cl_cb_conn;

      dprintk("NFSD alloc_init_deleg\n");
      if (fp->fi_had_conflict)
            return NULL;
      if (num_delegations > max_delegations)
            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_ident = cb->cb_ident;
      dp->dl_stateid.si_boot = get_seconds();
      dp->dl_stateid.si_stateownerid = current_delegid++;
      dp->dl_stateid.si_fileid = 0;
      dp->dl_stateid.si_generation = 0;
      fh_copy_shallow(&dp->dl_fh, &current_fh->fh_handle);
      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)
            vfs_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 void unhash_generic_stateid(struct nfs4_stateid *stp)
{
      list_del(&stp->st_hash);
      list_del(&stp->st_perfile);
      list_del(&stp->st_perstateowner);
}

static void free_generic_stateid(struct nfs4_stateid *stp)
{
      put_nfs4_file(stp->st_file);
      kmem_cache_free(stateid_slab, stp);
}

static void release_lock_stateid(struct nfs4_stateid *stp)
{
      unhash_generic_stateid(stp);
      locks_remove_posix(stp->st_vfs_file, (fl_owner_t)stp->st_stateowner);
      free_generic_stateid(stp);
}

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

      list_del(&sop->so_idhash);
      list_del(&sop->so_strhash);
      list_del(&sop->so_perstateid);
      while (!list_empty(&sop->so_stateids)) {
            stp = list_first_entry(&sop->so_stateids,
                        struct nfs4_stateid, st_perstateowner);
            release_lock_stateid(stp);
      }
}

static void release_lockowner(struct nfs4_stateowner *sop)
{
      unhash_lockowner(sop);
      nfs4_put_stateowner(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_lockowner(lock_sop);
      }
}

static void release_open_stateid(struct nfs4_stateid *stp)
{
      unhash_generic_stateid(stp);
      release_stateid_lockowners(stp);
      nfsd_close(stp->st_vfs_file);
      free_generic_stateid(stp);
}

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

      list_del(&sop->so_idhash);
      list_del(&sop->so_strhash);
      list_del(&sop->so_perclient);
      list_del(&sop->so_perstateid); /* XXX: necessary? */
      while (!list_empty(&sop->so_stateids)) {
            stp = list_first_entry(&sop->so_stateids,
                        struct nfs4_stateid, st_perstateowner);
            release_open_stateid(stp);
      }
}

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

static DEFINE_SPINLOCK(sessionid_lock);
#define SESSION_HASH_SIZE     512
static struct list_head sessionid_hashtbl[SESSION_HASH_SIZE];

static inline int
hash_sessionid(struct nfs4_sessionid *sessionid)
{
      struct nfsd4_sessionid *sid = (struct nfsd4_sessionid *)sessionid;

      return sid->sequence % SESSION_HASH_SIZE;
}

static inline void
dump_sessionid(const char *fn, struct nfs4_sessionid *sessionid)
{
      u32 *ptr = (u32 *)(&sessionid->data[0]);
      dprintk("%s: %u:%u:%u:%u\n", fn, ptr[0], ptr[1], ptr[2], ptr[3]);
}

static void
gen_sessionid(struct nfsd4_session *ses)
{
      struct nfs4_client *clp = ses->se_client;
      struct nfsd4_sessionid *sid;

      sid = (struct nfsd4_sessionid *)ses->se_sessionid.data;
      sid->clientid = clp->cl_clientid;
      sid->sequence = current_sessionid++;
      sid->reserved = 0;
}

/*
 * Give the client the number of slots it requests bound by
 * NFSD_MAX_SLOTS_PER_SESSION and by sv_drc_max_pages.
 *
 * If we run out of pages (sv_drc_pages_used == sv_drc_max_pages) we
 * should (up to a point) re-negotiate active sessions and reduce their
 * slot usage to make rooom for new connections. For now we just fail the
 * create session.
 */
static int set_forechannel_maxreqs(struct nfsd4_channel_attrs *fchan)
{
      int status = 0, np = fchan->maxreqs * NFSD_PAGES_PER_SLOT;

      if (fchan->maxreqs < 1)
            return nfserr_inval;
      else if (fchan->maxreqs > NFSD_MAX_SLOTS_PER_SESSION)
            fchan->maxreqs = NFSD_MAX_SLOTS_PER_SESSION;

      spin_lock(&nfsd_serv->sv_lock);
      if (np + nfsd_serv->sv_drc_pages_used > nfsd_serv->sv_drc_max_pages)
            np = nfsd_serv->sv_drc_max_pages - nfsd_serv->sv_drc_pages_used;
      nfsd_serv->sv_drc_pages_used += np;
      spin_unlock(&nfsd_serv->sv_lock);

      if (np <= 0) {
            status = nfserr_resource;
            fchan->maxreqs = 0;
      } else
            fchan->maxreqs = np / NFSD_PAGES_PER_SLOT;

      return status;
}

/*
 * fchan holds the client values on input, and the server values on output
 */
static int init_forechannel_attrs(struct svc_rqst *rqstp,
                          struct nfsd4_channel_attrs *session_fchan,
                          struct nfsd4_channel_attrs *fchan)
{
      int status = 0;
      __u32   maxcount = svc_max_payload(rqstp);

      /* headerpadsz set to zero in encode routine */

      /* Use the client's max request and max response size if possible */
      if (fchan->maxreq_sz > maxcount)
            fchan->maxreq_sz = maxcount;
      session_fchan->maxreq_sz = fchan->maxreq_sz;

      if (fchan->maxresp_sz > maxcount)
            fchan->maxresp_sz = maxcount;
      session_fchan->maxresp_sz = fchan->maxresp_sz;

      /* Set the max response cached size our default which is
       * a multiple of PAGE_SIZE and small */
      session_fchan->maxresp_cached = NFSD_PAGES_PER_SLOT * PAGE_SIZE;
      fchan->maxresp_cached = session_fchan->maxresp_cached;

      /* Use the client's maxops if possible */
      if (fchan->maxops > NFSD_MAX_OPS_PER_COMPOUND)
            fchan->maxops = NFSD_MAX_OPS_PER_COMPOUND;
      session_fchan->maxops = fchan->maxops;

      /* try to use the client requested number of slots */
      if (fchan->maxreqs > NFSD_MAX_SLOTS_PER_SESSION)
            fchan->maxreqs = NFSD_MAX_SLOTS_PER_SESSION;

      /* FIXME: Error means no more DRC pages so the server should
       * recover pages from existing sessions. For now fail session
       * creation.
       */
      status = set_forechannel_maxreqs(fchan);

      session_fchan->maxreqs = fchan->maxreqs;
      return status;
}

static int
alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp,
               struct nfsd4_create_session *cses)
{
      struct nfsd4_session *new, tmp;
      int idx, status = nfserr_resource, slotsize;

      memset(&tmp, 0, sizeof(tmp));

      /* FIXME: For now, we just accept the client back channel attributes. */
      tmp.se_bchannel = cses->back_channel;
      status = init_forechannel_attrs(rqstp, &tmp.se_fchannel,
                              &cses->fore_channel);
      if (status)
            goto out;

      /* allocate struct nfsd4_session and slot table in one piece */
      slotsize = tmp.se_fchannel.maxreqs * sizeof(struct nfsd4_slot);
      new = kzalloc(sizeof(*new) + slotsize, GFP_KERNEL);
      if (!new)
            goto out;

      memcpy(new, &tmp, sizeof(*new));

      new->se_client = clp;
      gen_sessionid(new);
      idx = hash_sessionid(&new->se_sessionid);
      memcpy(clp->cl_sessionid.data, new->se_sessionid.data,
             NFS4_MAX_SESSIONID_LEN);

      new->se_flags = cses->flags;
      kref_init(&new->se_ref);
      spin_lock(&sessionid_lock);
      list_add(&new->se_hash, &sessionid_hashtbl[idx]);
      list_add(&new->se_perclnt, &clp->cl_sessions);
      spin_unlock(&sessionid_lock);

      status = nfs_ok;
out:
      return status;
}

/* caller must hold sessionid_lock */
static struct nfsd4_session *
find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid)
{
      struct nfsd4_session *elem;
      int idx;

      dump_sessionid(__func__, sessionid);
      idx = hash_sessionid(sessionid);
      dprintk("%s: idx is %d\n", __func__, idx);
      /* Search in the appropriate list */
      list_for_each_entry(elem, &sessionid_hashtbl[idx], se_hash) {
            dump_sessionid("list traversal", &elem->se_sessionid);
            if (!memcmp(elem->se_sessionid.data, sessionid->data,
                      NFS4_MAX_SESSIONID_LEN)) {
                  return elem;
            }
      }

      dprintk("%s: session not found\n", __func__);
      return NULL;
}

/* caller must hold sessionid_lock */
static void
unhash_session(struct nfsd4_session *ses)
{
      list_del(&ses->se_hash);
      list_del(&ses->se_perclnt);
}

static void
release_session(struct nfsd4_session *ses)
{
      spin_lock(&sessionid_lock);
      unhash_session(ses);
      spin_unlock(&sessionid_lock);
      nfsd4_put_session(ses);
}

static void nfsd4_release_respages(struct page **respages, short resused);

void
free_session(struct kref *kref)
{
      struct nfsd4_session *ses;
      int i;

      ses = container_of(kref, struct nfsd4_session, se_ref);
      for (i = 0; i < ses->se_fchannel.maxreqs; i++) {
            struct nfsd4_cache_entry *e = &ses->se_slots[i].sl_cache_entry;
            nfsd4_release_respages(e->ce_respages, e->ce_resused);
      }
      kfree(ses);
}

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) boot_time %08lx\n",
            clid->cl_boot, clid->cl_id, boot_time);
      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 struct nfs4_client *alloc_client(struct xdr_netobj name)
{
      struct nfs4_client *clp;

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

static void
shutdown_callback_client(struct nfs4_client *clp)
{
      struct rpc_clnt *clnt = clp->cl_cb_conn.cb_client;

      if (clnt) {
            /*
             * Callback threads take a reference on the client, so there
             * should be no outstanding callbacks at this point.
             */
            clp->cl_cb_conn.cb_client = NULL;
            rpc_shutdown_client(clnt);
      }
      if (clp->cl_cb_conn.cb_cred) {
            put_rpccred(clp->cl_cb_conn.cb_cred);
            clp->cl_cb_conn.cb_cred = NULL;
      }
}

static inline void
free_client(struct nfs4_client *clp)
{
      shutdown_callback_client(clp);
      nfsd4_release_respages(clp->cl_slot.sl_cache_entry.ce_respages,
                       clp->cl_slot.sl_cache_entry.ce_resused);
      if (clp->cl_cred.cr_group_info)
            put_group_info(clp->cl_cred.cr_group_info);
      kfree(clp->cl_principal);
      kfree(clp->cl_name.data);
      kfree(clp);
}

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

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

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

      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_openowner(sop);
      }
      while (!list_empty(&clp->cl_sessions)) {
            struct nfsd4_session  *ses;
            ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,
                         se_perclnt);
            release_session(ses);
      }
      put_nfs4_client(clp);
}

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

      clp = alloc_client(name);
      if (clp == NULL)
            return NULL;
      memcpy(clp->cl_recdir, recdir, HEXDIR_LEN);
      atomic_set(&clp->cl_count, 1);
      atomic_set(&clp->cl_cb_conn.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_sessions);
      INIT_LIST_HEAD(&clp->cl_lru);
      return clp;
}

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

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

static void copy_cred(struct svc_cred *target, struct svc_cred *source)
{
      target->cr_uid = source->cr_uid;
      target->cr_gid = source->cr_gid;
      target->cr_group_info = source->cr_group_info;
      get_group_info(target->cr_group_info);
}

static int same_name(const char *n1, const char *n2)
{
      return 0 == memcmp(n1, n2, HEXDIR_LEN);
}

static int
same_verf(nfs4_verifier *v1, nfs4_verifier *v2)
{
      return 0 == memcmp(v1->data, v2->data, sizeof(v1->data));
}

static int
same_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
same_creds(struct svc_cred *cr1, struct svc_cred *cr2)
{
      return cr1->cr_uid == cr2->cr_uid;
}

static void gen_clid(struct nfs4_client *clp)
{
      static u32 current_clientid = 1;

      clp->cl_clientid.cl_boot = boot_time;
      clp->cl_clientid.cl_id = current_clientid++; 
}

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

      p = (u32 *)clp->cl_confirm.data;
      *p++ = get_seconds();
      *p++ = i++;
}

static int check_name(struct xdr_netobj name)
{
      if (name.len == 0) 
            return 0;
      if (name.len > NFS4_OPAQUE_LIMIT) {
            dprintk("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 (same_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 (same_clid(&clp->cl_clientid, clid))
                  return clp;
      }
      return NULL;
}

/*
 * Return 1 iff clp's clientid establishment method matches the use_exchange_id
 * parameter. Matching is based on the fact the at least one of the
 * EXCHGID4_FLAG_USE_{NON_PNFS,PNFS_MDS,PNFS_DS} flags must be set for v4.1
 *
 * FIXME: we need to unify the clientid namespaces for nfsv4.x
 * and correctly deal with client upgrade/downgrade in EXCHANGE_ID
 * and SET_CLIENTID{,_CONFIRM}
 */
static inline int
match_clientid_establishment(struct nfs4_client *clp, bool use_exchange_id)
{
      bool has_exchange_flags = (clp->cl_exchange_flags != 0);
      return use_exchange_id == has_exchange_flags;
}

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

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

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

      list_for_each_entry(clp, &unconf_str_hashtbl[hashval], cl_strhash) {
            if (same_name(clp->cl_recdir, dname) &&
                match_clientid_establishment(clp, use_exchange_id))
                  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_cb_conn *cb = &clp->cl_cb_conn;

      /* 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_minorversion = 0;
      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;
}

void
nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
{
      struct nfsd4_compoundres *resp = rqstp->rq_resp;

      resp->cstate.statp = statp;
}

/*
 * Dereference the result pages.
 */
static void
nfsd4_release_respages(struct page **respages, short resused)
{
      int i;

      dprintk("--> %s\n", __func__);
      for (i = 0; i < resused; i++) {
            if (!respages[i])
                  continue;
            put_page(respages[i]);
            respages[i] = NULL;
      }
}

static void
nfsd4_copy_pages(struct page **topages, struct page **frompages, short count)
{
      int i;

      for (i = 0; i < count; i++) {
            topages[i] = frompages[i];
            if (!topages[i])
                  continue;
            get_page(topages[i]);
      }
}

/*
 * Cache the reply pages up to NFSD_PAGES_PER_SLOT + 1, clearing the previous
 * pages. We add a page to NFSD_PAGES_PER_SLOT for the case where the total
 * length of the XDR response is less than se_fmaxresp_cached
 * (NFSD_PAGES_PER_SLOT * PAGE_SIZE) but the xdr_buf pages is used for a
 * of the reply (e.g. readdir).
 *
 * Store the base and length of the rq_req.head[0] page
 * of the NFSv4.1 data, just past the rpc header.
 */
void
nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
{
      struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
      struct svc_rqst *rqstp = resp->rqstp;
      struct nfsd4_compoundargs *args = rqstp->rq_argp;
      struct nfsd4_op *op = &args->ops[resp->opcnt];
      struct kvec *resv = &rqstp->rq_res.head[0];

      dprintk("--> %s entry %p\n", __func__, entry);

      /* Don't cache a failed OP_SEQUENCE. */
      if (resp->opcnt == 1 && op->opnum == OP_SEQUENCE && resp->cstate.status)
            return;

      nfsd4_release_respages(entry->ce_respages, entry->ce_resused);
      entry->ce_opcnt = resp->opcnt;
      entry->ce_status = resp->cstate.status;

      /*
       * Don't need a page to cache just the sequence operation - the slot
       * does this for us!
       */

      if (nfsd4_not_cached(resp)) {
            entry->ce_resused = 0;
            entry->ce_rpchdrlen = 0;
            dprintk("%s Just cache SEQUENCE. ce_cachethis %d\n", __func__,
                  resp->cstate.slot->sl_cache_entry.ce_cachethis);
            return;
      }
      entry->ce_resused = rqstp->rq_resused;
      if (entry->ce_resused > NFSD_PAGES_PER_SLOT + 1)
            entry->ce_resused = NFSD_PAGES_PER_SLOT + 1;
      nfsd4_copy_pages(entry->ce_respages, rqstp->rq_respages,
                   entry->ce_resused);
      entry->ce_datav.iov_base = resp->cstate.statp;
      entry->ce_datav.iov_len = resv->iov_len - ((char *)resp->cstate.statp -
                        (char *)page_address(rqstp->rq_respages[0]));
      /* Current request rpc header length*/
      entry->ce_rpchdrlen = (char *)resp->cstate.statp -
                        (char *)page_address(rqstp->rq_respages[0]);
}

/*
 * We keep the rpc header, but take the nfs reply from the replycache.
 */
static int
nfsd41_copy_replay_data(struct nfsd4_compoundres *resp,
                  struct nfsd4_cache_entry *entry)
{
      struct svc_rqst *rqstp = resp->rqstp;
      struct kvec *resv = &resp->rqstp->rq_res.head[0];
      int len;

      /* Current request rpc header length*/
      len = (char *)resp->cstate.statp -
                  (char *)page_address(rqstp->rq_respages[0]);
      if (entry->ce_datav.iov_len + len > PAGE_SIZE) {
            dprintk("%s v41 cached reply too large (%Zd).\n", __func__,
                  entry->ce_datav.iov_len);
            return 0;
      }
      /* copy the cached reply nfsd data past the current rpc header */
      memcpy((char *)resv->iov_base + len, entry->ce_datav.iov_base,
            entry->ce_datav.iov_len);
      resv->iov_len = len + entry->ce_datav.iov_len;
      return 1;
}

/*
 * Keep the first page of the replay. Copy the NFSv4.1 data from the first
 * cached page.  Replace any futher replay pages from the cache.
 */
__be32
nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
                   struct nfsd4_sequence *seq)
{
      struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
      __be32 status;

      dprintk("--> %s entry %p\n", __func__, entry);

      /*
       * If this is just the sequence operation, we did not keep
       * a page in the cache entry because we can just use the
       * slot info stored in struct nfsd4_sequence that was checked
       * against the slot in nfsd4_sequence().
       *
       * This occurs when seq->cachethis is FALSE, or when the client
       * session inactivity timer fires and a solo sequence operation
       * is sent (lease renewal).
       */
      if (seq && nfsd4_not_cached(resp)) {
            seq->maxslots = resp->cstate.session->se_fchannel.maxreqs;
            return nfs_ok;
      }

      if (!nfsd41_copy_replay_data(resp, entry)) {
            /*
             * Not enough room to use the replay rpc header, send the
             * cached header. Release all the allocated result pages.
             */
            svc_free_res_pages(resp->rqstp);
            nfsd4_copy_pages(resp->rqstp->rq_respages, entry->ce_respages,
                  entry->ce_resused);
      } else {
            /* Release all but the first allocated result page */

            resp->rqstp->rq_resused--;
            svc_free_res_pages(resp->rqstp);

            nfsd4_copy_pages(&resp->rqstp->rq_respages[1],
                         &entry->ce_respages[1],
                         entry->ce_resused - 1);
      }

      resp->rqstp->rq_resused = entry->ce_resused;
      resp->opcnt = entry->ce_opcnt;
      resp->cstate.iovlen = entry->ce_datav.iov_len + entry->ce_rpchdrlen;
      status = entry->ce_status;

      return status;
}

/*
 * Set the exchange_id flags returned by the server.
 */
static void
nfsd4_set_ex_flags(struct nfs4_client *new, struct nfsd4_exchange_id *clid)
{
      /* pNFS is not supported */
      new->cl_exchange_flags |= EXCHGID4_FLAG_USE_NON_PNFS;

      /* Referrals are supported, Migration is not. */
      new->cl_exchange_flags |= EXCHGID4_FLAG_SUPP_MOVED_REFER;

      /* set the wire flags to return to client. */
      clid->flags = new->cl_exchange_flags;
}

__be32
nfsd4_exchange_id(struct svc_rqst *rqstp,
              struct nfsd4_compound_state *cstate,
              struct nfsd4_exchange_id *exid)
{
      struct nfs4_client *unconf, *conf, *new;
      int status;
      unsigned int            strhashval;
      char              dname[HEXDIR_LEN];
      nfs4_verifier           verf = exid->verifier;
      u32               ip_addr = svc_addr_in(rqstp)->sin_addr.s_addr;

      dprintk("%s rqstp=%p exid=%p clname.len=%u clname.data=%p "
            " ip_addr=%u flags %x, spa_how %d\n",
            __func__, rqstp, exid, exid->clname.len, exid->clname.data,
            ip_addr, exid->flags, exid->spa_how);

      if (!check_name(exid->clname) || (exid->flags & ~EXCHGID4_FLAG_MASK_A))
            return nfserr_inval;

      /* Currently only support SP4_NONE */
      switch (exid->spa_how) {
      case SP4_NONE:
            break;
      case SP4_SSV:
            return nfserr_encr_alg_unsupp;
      default:
            BUG();                        /* checked by xdr code */
      case SP4_MACH_CRED:
            return nfserr_serverfault;    /* no excuse :-/ */
      }

      status = nfs4_make_rec_clidname(dname, &exid->clname);

      if (status)
            goto error;

      strhashval = clientstr_hashval(dname);

      nfs4_lock_state();
      status = nfs_ok;

      conf = find_confirmed_client_by_str(dname, strhashval, true);
      if (conf) {
            if (!same_verf(&verf, &conf->cl_verifier)) {
                  /* 18.35.4 case 8 */
                  if (exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A) {
                        status = nfserr_not_same;
                        goto out;
                  }
                  /* Client reboot: destroy old state */
                  expire_client(conf);
                  goto out_new;
            }
            if (!same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
                  /* 18.35.4 case 9 */
                  if (exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A) {
                        status = nfserr_perm;
                        goto out;
                  }
                  expire_client(conf);
                  goto out_new;
            }
            /*
             * Set bit when the owner id and verifier map to an already
             * confirmed client id (18.35.3).
             */
            exid->flags |= EXCHGID4_FLAG_CONFIRMED_R;

            /*
             * Falling into 18.35.4 case 2, possible router replay.
             * Leave confirmed record intact and return same result.
             */
            copy_verf(conf, &verf);
            new = conf;
            goto out_copy;
      }

      /* 18.35.4 case 7 */
      if (exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A) {
            status = nfserr_noent;
            goto out;
      }

      unconf  = find_unconfirmed_client_by_str(dname, strhashval, true);
      if (unconf) {
            /*
             * Possible retry or client restart.  Per 18.35.4 case 4,
             * a new unconfirmed record should be generated regardless
             * of whether any properties have changed.
             */
            expire_client(unconf);
      }

out_new:
      /* Normal case */
      new = create_client(exid->clname, dname);
      if (new == NULL) {
            status = nfserr_resource;
            goto out;
      }

      copy_verf(new, &verf);
      copy_cred(&new->cl_cred, &rqstp->rq_cred);
      new->cl_addr = ip_addr;
      gen_clid(new);
      gen_confirm(new);
      add_to_unconfirmed(new, strhashval);
out_copy:
      exid->clientid.cl_boot = new->cl_clientid.cl_boot;
      exid->clientid.cl_id = new->cl_clientid.cl_id;

      new->cl_slot.sl_seqid = 0;
      exid->seqid = 1;
      nfsd4_set_ex_flags(new, exid);

      dprintk("nfsd4_exchange_id seqid %d flags %x\n",
            new->cl_slot.sl_seqid, new->cl_exchange_flags);
      status = nfs_ok;

out:
      nfs4_unlock_state();
error:
      dprintk("nfsd4_exchange_id returns %d\n", ntohl(status));
      return status;
}

static int
check_slot_seqid(u32 seqid, struct nfsd4_slot *slot)
{
      dprintk("%s enter. seqid %d slot->sl_seqid %d\n", __func__, seqid,
            slot->sl_seqid);

      /* The slot is in use, and no response has been sent. */
      if (slot->sl_inuse) {
            if (seqid == slot->sl_seqid)
                  return nfserr_jukebox;
            else
                  return nfserr_seq_misordered;
      }
      /* Normal */
      if (likely(seqid == slot->sl_seqid + 1))
            return nfs_ok;
      /* Replay */
      if (seqid == slot->sl_seqid)
            return nfserr_replay_cache;
      /* Wraparound */
      if (seqid == 1 && (slot->sl_seqid + 1) == 0)
            return nfs_ok;
      /* Misordered replay or misordered new request */
      return nfserr_seq_misordered;
}

__be32
nfsd4_create_session(struct svc_rqst *rqstp,
                 struct nfsd4_compound_state *cstate,
                 struct nfsd4_create_session *cr_ses)
{
      u32 ip_addr = svc_addr_in(rqstp)->sin_addr.s_addr;
      struct nfsd4_compoundres *resp = rqstp->rq_resp;
      struct nfs4_client *conf, *unconf;
      struct nfsd4_slot *slot = NULL;
      int status = 0;

      nfs4_lock_state();
      unconf = find_unconfirmed_client(&cr_ses->clientid);
      conf = find_confirmed_client(&cr_ses->clientid);

      if (conf) {
            slot = &conf->cl_slot;
            status = check_slot_seqid(cr_ses->seqid, slot);
            if (status == nfserr_replay_cache) {
                  dprintk("Got a create_session replay! seqid= %d\n",
                        slot->sl_seqid);
                  cstate->slot = slot;
                  cstate->status = status;
                  /* Return the cached reply status */
                  status = nfsd4_replay_cache_entry(resp, NULL);
                  goto out;
            } else if (cr_ses->seqid != conf->cl_slot.sl_seqid + 1) {
                  status = nfserr_seq_misordered;
                  dprintk("Sequence misordered!\n");
                  dprintk("Expected seqid= %d but got seqid= %d\n",
                        slot->sl_seqid, cr_ses->seqid);
                  goto out;
            }
            conf->cl_slot.sl_seqid++;
      } else if (unconf) {
            if (!same_creds(&unconf->cl_cred, &rqstp->rq_cred) ||
                (ip_addr != unconf->cl_addr)) {
                  status = nfserr_clid_inuse;
                  goto out;
            }

            slot = &unconf->cl_slot;
            status = check_slot_seqid(cr_ses->seqid, slot);
            if (status) {
                  /* an unconfirmed replay returns misordered */
                  status = nfserr_seq_misordered;
                  goto out;
            }

            slot->sl_seqid++; /* from 0 to 1 */
            move_to_confirmed(unconf);

            /*
             * We do not support RDMA or persistent sessions
             */
            cr_ses->flags &= ~SESSION4_PERSIST;
            cr_ses->flags &= ~SESSION4_RDMA;

            conf = unconf;
      } else {
            status = nfserr_stale_clientid;
            goto out;
      }

      status = alloc_init_session(rqstp, conf, cr_ses);
      if (status)
            goto out;

      memcpy(cr_ses->sessionid.data, conf->cl_sessionid.data,
             NFS4_MAX_SESSIONID_LEN);
      cr_ses->seqid = slot->sl_seqid;

      slot->sl_inuse = true;
      cstate->slot = slot;
      /* Ensure a page is used for the cache */
      slot->sl_cache_entry.ce_cachethis = 1;
out:
      nfs4_unlock_state();
      dprintk("%s returns %d\n", __func__, ntohl(status));
      return status;
}

__be32
nfsd4_destroy_session(struct svc_rqst *r,
                  struct nfsd4_compound_state *cstate,
                  struct nfsd4_destroy_session *sessionid)
{
      struct nfsd4_session *ses;
      u32 status = nfserr_badsession;

      /* Notes:
       * - The confirmed nfs4_client->cl_sessionid holds destroyed sessinid
       * - Should we return nfserr_back_chan_busy if waiting for
       *   callbacks on to-be-destroyed session?
       * - Do we need to clear any callback info from previous session?
       */

      dump_sessionid(__func__, &sessionid->sessionid);
      spin_lock(&sessionid_lock);
      ses = find_in_sessionid_hashtbl(&sessionid->sessionid);
      if (!ses) {
            spin_unlock(&sessionid_lock);
            goto out;
      }

      unhash_session(ses);
      spin_unlock(&sessionid_lock);

      /* wait for callbacks */
      shutdown_callback_client(ses->se_client);
      nfsd4_put_session(ses);
      status = nfs_ok;
out:
      dprintk("%s returns %d\n", __func__, ntohl(status));
      return status;
}

__be32
nfsd4_sequence(struct svc_rqst *rqstp,
             struct nfsd4_compound_state *cstate,
             struct nfsd4_sequence *seq)
{
      struct nfsd4_compoundres *resp = rqstp->rq_resp;
      struct nfsd4_session *session;
      struct nfsd4_slot *slot;
      int status;

      if (resp->opcnt != 1)
            return nfserr_sequence_pos;

      spin_lock(&sessionid_lock);
      status = nfserr_badsession;
      session = find_in_sessionid_hashtbl(&seq->sessionid);
      if (!session)
            goto out;

      status = nfserr_badslot;
      if (seq->slotid >= session->se_fchannel.maxreqs)
            goto out;

      slot = &session->se_slots[seq->slotid];
      dprintk("%s: slotid %d\n", __func__, seq->slotid);

      status = check_slot_seqid(seq->seqid, slot);
      if (status == nfserr_replay_cache) {
            cstate->slot = slot;
            cstate->session = session;
            /* Return the cached reply status and set cstate->status
             * for nfsd4_svc_encode_compoundres processing */
            status = nfsd4_replay_cache_entry(resp, seq);
            cstate->status = nfserr_replay_cache;
            goto replay_cache;
      }
      if (status)
            goto out;

      /* Success! bump slot seqid */
      slot->sl_inuse = true;
      slot->sl_seqid = seq->seqid;
      slot->sl_cache_entry.ce_cachethis = seq->cachethis;
      /* Always set the cache entry cachethis for solo sequence */
      if (nfsd4_is_solo_sequence(resp))
            slot->sl_cache_entry.ce_cachethis = 1;

      cstate->slot = slot;
      cstate->session = session;

replay_cache:
      /* Renew the clientid on success and on replay.
       * Hold a session reference until done processing the compound:
       * nfsd4_put_session called only if the cstate slot is set.
       */
      renew_client(session->se_client);
      nfsd4_get_session(session);
out:
      spin_unlock(&sessionid_lock);
      dprintk("%s: return %d\n", __func__, ntohl(status));
      return status;
}

__be32
nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              struct nfsd4_setclientid *setclid)
{
      struct sockaddr_in      *sin = svc_addr_in(rqstp);
      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;
      __be32                  status;
      char              *princ;
      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, false);
      if (conf) {
            /* RFC 3530 14.2.33 CASE 0: */
            status = nfserr_clid_inuse;
            if (!same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
                  dprintk("NFSD: setclientid: string in use by client"
                        " at %pI4\n", &conf->cl_addr);
                  goto out;
            }
      }
      /*
       * section 14.2.33 of RFC 3530 (under the heading "IMPLEMENTATION")
       * has a description of SETCLIENTID request processing consisting
       * of 5 bullet points, labeled as CASE0 - CASE4 below.
       */
      unconf = find_unconfirmed_client_by_str(dname, strhashval, false);
      status = nfserr_resource;
      if (!conf) {
            /*
             * RFC 3530 14.2.33 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;
            gen_clid(new);
      } else if (same_verf(&conf->cl_verifier, &clverifier)) {
            /*
             * RFC 3530 14.2.33 CASE 1:
             * probable callback update
             */
            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_clid(new, conf);
      } else if (!unconf) {
            /*
             * RFC 3530 14.2.33 CASE 2:
             * probable client reboot; state will be removed if
             * confirmed.
             */
            new = create_client(clname, dname);
            if (new == NULL)
                  goto out;
            gen_clid(new);
      } else {
            /*
             * RFC 3530 14.2.33 CASE 3:
             * probable client reboot; state will be removed if
             * confirmed.
             */
            expire_client(unconf);
            new = create_client(clname, dname);
            if (new == NULL)
                  goto out;
            gen_clid(new);
      }
      copy_verf(new, &clverifier);
      new->cl_addr = sin->sin_addr.s_addr;
      new->cl_flavor = rqstp->rq_flavor;
      princ = svc_gss_principal(rqstp);
      if (princ) {
            new->cl_principal = kstrdup(princ, GFP_KERNEL);
            if (new->cl_principal == NULL) {
                  free_client(new);
                  goto out;
            }
      }
      copy_cred(&new->cl_cred, &rqstp->rq_cred);
      gen_confirm(new);
      gen_callback(new, setclid);
      add_to_unconfirmed(new, strhashval);
      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;
}


/*
 * Section 14.2.34 of RFC 3530 (under the heading "IMPLEMENTATION") has
 * a description of SETCLIENTID_CONFIRM request processing consisting of 4
 * bullets, labeled as CASE1 - CASE4 below.
 */
__be32
nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
                   struct nfsd4_compound_state *cstate,
                   struct nfsd4_setclientid_confirm *setclientid_confirm)
{
      struct sockaddr_in *sin = svc_addr_in(rqstp);
      struct nfs4_client *conf, *unconf;
      nfs4_verifier confirm = setclientid_confirm->sc_confirm; 
      clientid_t * clid = &setclientid_confirm->sc_clientid;
      __be32 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 != sin->sin_addr.s_addr)
            goto out;
      if (unconf && unconf->cl_addr != sin->sin_addr.s_addr)
            goto out;

      /*
       * section 14.2.34 of RFC 3530 has a description of
       * SETCLIENTID_CONFIRM request processing consisting
       * of 4 bullet points, labeled as CASE1 - CASE4 below.
       */
      if (conf && unconf && same_verf(&confirm, &unconf->cl_confirm)) {
            /*
             * RFC 3530 14.2.34 CASE 1:
             * callback update
             */
            if (!same_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_cb_conn.cb_set, 0);
                  expire_client(unconf);
                  status = nfs_ok;

            }
      } else if (conf && !unconf) {
            /*
             * RFC 3530 14.2.34 CASE 2:
             * probable retransmitted request; play it safe and
             * do nothing.
             */
            if (!same_creds(&conf->cl_cred, &rqstp->rq_cred))
                  status = nfserr_clid_inuse;
            else
                  status = nfs_ok;
      } else if (!conf && unconf
                  && same_verf(&unconf->cl_confirm, &confirm)) {
            /*
             * RFC 3530 14.2.34 CASE 3:
             * Normal case; new or rebooted client:
             */
            if (!same_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, false);
                  if (conf) {
                        nfsd4_remove_clid_dir(conf);
                        expire_client(conf);
                  }
                  move_to_confirmed(unconf);
                  conf = unconf;
                  nfsd4_probe_callback(conf);
                  status = nfs_ok;
            }
      } else if ((!conf || (conf && !same_verf(&conf->cl_confirm, &confirm)))
          && (!unconf || (unconf && !same_verf(&unconf->cl_confirm,
                                                &confirm)))) {
            /*
             * RFC 3530 14.2.34 CASE 4:
             * Client probably hasn't noticed that we rebooted yet.
             */
            status = nfserr_stale_clientid;
      } else {
            /* check that we have hit one of the cases...*/
            status = nfserr_clid_inuse;
      }
out:
      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) {
            atomic_set(&fp->fi_ref, 1);
            INIT_LIST_HEAD(&fp->fi_hash);
            INIT_LIST_HEAD(&fp->fi_stateids);
            INIT_LIST_HEAD(&fp->fi_delegations);
            spin_lock(&recall_lock);
            list_add(&fp->fi_hash, &file_hashtbl[hashval]);
            spin_unlock(&recall_lock);
            fp->fi_inode = igrab(ino);
            fp->fi_id = current_fileid++;
            fp->fi_had_conflict = false;
            return fp;
      }
      return NULL;
}

static void
nfsd4_free_slab(struct kmem_cache **slab)
{
      if (*slab == NULL)
            return;
      kmem_cache_destroy(*slab);
      *slab = NULL;
}

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);
      if (stateowner_slab == NULL)
            goto out_nomem;
      file_slab = kmem_cache_create("nfsd4_files",
                  sizeof(struct nfs4_file), 0, 0, NULL);
      if (file_slab == NULL)
            goto out_nomem;
      stateid_slab = kmem_cache_create("nfsd4_stateids",
                  sizeof(struct nfs4_stateid), 0, 0, NULL);
      if (stateid_slab == NULL)
            goto out_nomem;
      deleg_slab = kmem_cache_create("nfsd4_delegations",
                  sizeof(struct nfs4_delegation), 0, 0, 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 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 = get_seconds();
      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 & ~NFS4_SHARE_WANT_MASK,
              &stp->st_access_bmap);
      __set_bit(open->op_share_deny, &stp->st_deny_bmap);
      stp->st_openstp = NULL;
}

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
same_owner_str(struct nfs4_stateowner *sop, struct xdr_netobj *owner,
                                          clientid_t *clid)
{
      return (sop->so_owner.len == owner->len) &&
            0 == 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 (same_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;

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

static inline int access_valid(u32 x, u32 minorversion)
{
      if ((x & NFS4_SHARE_ACCESS_MASK) < NFS4_SHARE_ACCESS_READ)
            return 0;
      if ((x & NFS4_SHARE_ACCESS_MASK) > NFS4_SHARE_ACCESS_BOTH)
            return 0;
      x &= ~NFS4_SHARE_ACCESS_MASK;
      if (minorversion && x) {
            if ((x & NFS4_SHARE_WANT_MASK) > NFS4_SHARE_WANT_CANCEL)
                  return 0;
            if ((x & NFS4_SHARE_WHEN_MASK) > NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED)
                  return 0;
            x &= ~(NFS4_SHARE_WANT_MASK | NFS4_SHARE_WHEN_MASK);
      }
      if (x)
            return 0;
      return 1;
}

static inline int deny_valid(u32 x)
{
      /* Note: unlike access bits, deny bits may be zero. */
      return x <= NFS4_SHARE_DENY_BOTH;
}

/*
 * We store the NONE, READ, WRITE, and BOTH bits separately in the
 * st_{access,deny}_bmap field of the stateid, in order to track not
 * only what share bits are currently in force, but also what
 * combinations of share bits previous opens have used.  This allows us
 * to enforce the recommendation of rfc 3530 14.2.19 that the server
 * return an error if the client attempt to downgrade to a combination
 * of share bits not explicable by closing some of its previous opens.
 *
 * XXX: This enforcement is actually incomplete, since we don't keep
 * track of access/deny bit combinations; so, e.g., we allow:
 *
 *    OPEN allow read, deny write
 *    OPEN allow both, deny none
 *    DOWNGRADE allow read, deny none
 *
 * which we should reject.
 */
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 __be32
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;
      __be32 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) {
            drop_file_write_access(filp);
            filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE;
      }
}

/*
 * 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;

      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);
      atomic_inc(&dp->dl_client->cl_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();

      /*
       * We don't want the locks code to timeout the lease for us;
       * we'll remove it ourself if the delegation isn't returned
       * in time.
       */
      fl->fl_break_time = 0;

      dp->dl_file->fi_had_conflict = true;
      nfsd4_cb_recall(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,
};


__be32
nfsd4_process_open1(struct nfsd4_compound_state *cstate,
                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;
      }
      /* When sessions are used, skip open sequenceid processing */
      if (nfsd4_has_session(cstate))
            goto renew;
      if (!sop->so_confirmed) {
            /* Replace unconfirmed owners without checking for replay. */
            clp = sop->so_client;
            release_openowner(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 __be32
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 __be32
nfs4_check_deleg(struct nfs4_file *fp, struct nfsd4_open *open,
            struct nfs4_delegation **dp)
{
      int flags;
      __be32 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 __be32
nfs4_check_open(struct nfs4_file *fp, struct nfsd4_open *open, struct nfs4_stateid **stpp)
{
      struct nfs4_stateid *local;
      __be32 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 __be32
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 {
            __be32 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 __be32
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 __be32
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_path.dentry->d_inode;
      unsigned int share_access, new_writer;
      __be32 status;

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

      if (new_writer) {
            int err = get_write_access(inode);
            if (err)
                  return nfserrno(err);
            err = mnt_want_write(cur_fh->fh_export->ex_path.mnt);
            if (err)
                  return nfserrno(err);
            file_take_write(filp);
      }
      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_cb_conn *cb = &sop->so_client->cl_cb_conn;
      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 (locks_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_type = flag == NFS4_OPEN_DELEGATE_READ? F_RDLCK: F_WRLCK;
      fl.fl_end = OFFSET_MAX;
      fl.fl_owner =  (fl_owner_t)dp;
      fl.fl_file = stp->st_vfs_file;
      fl.fl_pid = current->tgid;

      /* vfs_setlease checks to see if delegation should be handed out.
       * the lock_manager callbacks fl_mylease and fl_change are used
       */
      if ((status = vfs_setlease(stp->st_vfs_file, fl.fl_type, &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)
            dprintk("NFSD: WARNING: refusing delegation reclaim\n");
      open->op_delegate_type = flag;
}

/*
 * called with nfs4_lock_state() held.
 */
__be32
nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
{
      struct nfsd4_compoundres *resp = rqstp->rq_resp;
      struct nfs4_file *fp = NULL;
      struct inode *ino = current_fh->fh_dentry->d_inode;
      struct nfs4_stateid *stp = NULL;
      struct nfs4_delegation *dp = NULL;
      __be32 status;

      status = nfserr_inval;
      if (!access_valid(open->op_share_access, resp->cstate.minorversion)
                  || !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 |= NFSD_MAY_READ;
            if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
                  flags |= NFSD_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_open_stateid(stp);
                  goto out;
            }
            if (nfsd4_has_session(&resp->cstate))
                  update_stateid(&stp->st_stateid);
      }
      memcpy(&open->op_stateid, &stp->st_stateid, sizeof(stateid_t));

      if (nfsd4_has_session(&resp->cstate))
            open->op_stateowner->so_confirmed = 1;

      /*
      * 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 &&
          !nfsd4_has_session(&resp->cstate))
            open->op_rflags |= NFS4_OPEN_RESULT_CONFIRM;

      return status;
}

__be32
nfsd4_renew(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
          clientid_t *clid)
{
      struct nfs4_client *clp;
      __be32 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_cb_conn.cb_set))
            goto out;
      status = nfs_ok;
out:
      nfs4_unlock_state();
      return status;
}

struct lock_manager nfsd4_manager = {
};

static void
nfsd4_end_grace(void)
{
      dprintk("NFSD: end of grace period\n");
      nfsd4_recdir_purge_old();
      locks_end_grace(&nfsd4_manager);
}

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 (locks_in_grace())
            nfsd4_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_openowner(sop);
      }
      if (clientid_val < NFSD_LAUNDROMAT_MINTIMEOUT)
            clientid_val = NFSD_LAUNDROMAT_MINTIMEOUT;
      nfs4_unlock_state();
      return clientid_val;
}

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

static void
laundromat_main(struct work_struct *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_path.dentry->d_inode;
}

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

static int
EXPIRED_STATEID(stateid_t *stateid)
{
      if (time_before((unsigned long)boot_time,
                  ((unsigned long)stateid->si_boot)) &&
          time_before((unsigned long)(stateid->si_boot + lease_time), get_seconds())) {
            dprintk("NFSD: expired stateid (%08x/%08x/%08x/%08x)!\n",
                  stateid->si_boot, stateid->si_stateownerid,
                  stateid->si_fileid, stateid->si_generation);
            return 1;
      }
      return 0;
}

static __be32
stateid_error_map(stateid_t *stateid)
{
      if (STALE_STATEID(stateid))
            return nfserr_stale_stateid;
      if (EXPIRED_STATEID(stateid))
            return nfserr_expired;

      dprintk("NFSD: bad stateid (%08x/%08x/%08x/%08x)!\n",
            stateid->si_boot, stateid->si_stateownerid,
            stateid->si_fileid, stateid->si_generation);
      return nfserr_bad_stateid;
}

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
__be32 nfs4_check_openmode(struct nfs4_stateid *stp, int flags)
{
        __be32 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 __be32
check_special_stateids(svc_fh *current_fh, stateid_t *stateid, int flags)
{
      if (ONE_STATEID(stateid) && (flags & RD_STATE))
            return nfs_ok;
      else if (locks_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
grace_disallows_io(struct inode *inode)
{
      return locks_in_grace() && mandatory_lock(inode);
}

static int check_stateid_generation(stateid_t *in, stateid_t *ref, int flags)
{
      /*
       * When sessions are used the stateid generation number is ignored
       * when it is zero.
       */
      if ((flags & HAS_SESSION) && in->si_generation == 0)
            goto out;

      /* If the client sends us a stateid from the future, it's buggy: */
      if (in->si_generation > ref->si_generation)
            return nfserr_bad_stateid;
      /*
       * The following, however, can happen.  For example, if the
       * client sends an open and some IO at the same time, the open
       * may bump si_generation while the IO is still in flight.
       * Thanks to hard links and renames, the client never knows what
       * file an open will affect.  So it could avoid that situation
       * only by serializing all opens and IO from the same open
       * owner.  To recover from the old_stateid error, the client
       * will just have to retry the IO:
       */
      if (in->si_generation < ref->si_generation)
            return nfserr_old_stateid;
out:
      return nfs_ok;
}

static int is_delegation_stateid(stateid_t *stateid)
{
      return stateid->si_fileid == 0;
}

/*
* Checks for stateid operations
*/
__be32
nfs4_preprocess_stateid_op(struct nfsd4_compound_state *cstate,
                     stateid_t *stateid, int flags, struct file **filpp)
{
      struct nfs4_stateid *stp = NULL;
      struct nfs4_delegation *dp = NULL;
      struct svc_fh *current_fh = &cstate->current_fh;
      struct inode *ino = current_fh->fh_dentry->d_inode;
      __be32 status;

      if (filpp)
            *filpp = NULL;

      if (grace_disallows_io(ino))
            return nfserr_grace;

      if (nfsd4_has_session(cstate))
            flags |= HAS_SESSION;

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

      status = nfserr_stale_stateid;
      if (STALE_STATEID(stateid)) 
            goto out;

      status = nfserr_bad_stateid;
      if (is_delegation_stateid(stateid)) {
            dp = find_delegation_stateid(ino, stateid);
            if (!dp) {
                  status = stateid_error_map(stateid);
                  goto out;
            }
            status = check_stateid_generation(stateid, &dp->dl_stateid,
                                      flags);
            if (status)
                  goto out;
            status = nfs4_check_delegmode(dp, flags);
            if (status)
                  goto out;
            renew_client(dp->dl_client);
            if (filpp)
                  *filpp = dp->dl_vfs_file;
      } else { /* open or lock stateid */
            stp = find_stateid(stateid, flags);
            if (!stp) {
                  status = stateid_error_map(stateid);
                  goto out;
            }
            if (nfs4_check_fh(current_fh, stp))
                  goto out;
            if (!stp->st_stateowner->so_confirmed)
                  goto out;
            status = check_stateid_generation(stateid, &stp->st_stateid,
                                      flags);
            if (status)
                  goto out;
            status = nfs4_check_openmode(stp, flags);
            if (status)
                  goto out;
            renew_client(stp->st_stateowner->so_client);
            if (filpp)
                  *filpp = stp->st_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 __be32
nfs4_preprocess_seqid_op(struct nfsd4_compound_state *cstate, 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;
      struct svc_fh *current_fh = &cstate->current_fh;
      __be32 status;

      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)) {
            dprintk("NFSD: preprocess_seqid_op: magic stateid!\n");
            return nfserr_bad_stateid;
      }

      if (STALE_STATEID(stateid))
            return nfserr_stale_stateid;

      if (nfsd4_has_session(cstate))
            flags |= HAS_SESSION;

      /*
      * 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 stateid_error_map(stateid);
            *sopp = sop;
            goto check_replay;
      }

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

      if (lock) {
            clientid_t *lockclid = &lock->v.new.clientid;
            struct nfs4_client *clp = sop->so_client;
            int lkflg = 0;
            __be32 status;

            lkflg = setlkflg(lock->lk_type);

            if (lock->lk_is_new) {
                  if (!sop->so_is_open_owner)
                        return nfserr_bad_stateid;
                  if (!(flags & HAS_SESSION) &&
                      !same_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 (nfs4_check_fh(current_fh, stp)) {
            dprintk("NFSD: preprocess_seqid_op: fh-stateid mismatch!\n");
            return nfserr_bad_stateid;
      }

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

      if (sop->so_confirmed && flags & CONFIRM) {
            dprintk("NFSD: preprocess_seqid_op: expected"
                        " unconfirmed stateowner!\n");
            return nfserr_bad_stateid;
      }
      if (!sop->so_confirmed && !(flags & CONFIRM)) {
            dprintk("NFSD: preprocess_seqid_op: stateowner not"
                        " confirmed yet!\n");
            return nfserr_bad_stateid;
      }
      status = check_stateid_generation(stateid, &stp->st_stateid, flags);
      if (status)
            return status;
      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;
      }
      dprintk("NFSD: preprocess_seqid_op: bad seqid (expected %d, got %d)\n",
                  sop->so_seqid, seqid);
      *sopp = NULL;
      return nfserr_bad_seqid;
}

__be32
nfsd4_open_confirm(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
               struct nfsd4_open_confirm *oc)
{
      __be32 status;
      struct nfs4_stateowner *sop;
      struct nfs4_stateid *stp;

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

      status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0);
      if (status)
            return status;

      nfs4_lock_state();

      if ((status = nfs4_preprocess_seqid_op(cstate,
                              oc->oc_seqid, &oc->oc_req_stateid,
                              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);
            cstate->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);
      }
}

__be32
nfsd4_open_downgrade(struct svc_rqst *rqstp,
                 struct nfsd4_compound_state *cstate,
                 struct nfsd4_open_downgrade *od)
{
      __be32 status;
      struct nfs4_stateid *stp;
      unsigned int share_access;

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

      if (!access_valid(od->od_share_access, cstate->minorversion)
                  || !deny_valid(od->od_share_deny))
            return nfserr_inval;

      nfs4_lock_state();
      if ((status = nfs4_preprocess_seqid_op(cstate,
                              od->od_seqid,
                              &od->od_stateid, 
                              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);
            cstate->replay_owner = od->od_stateowner;
      }
      nfs4_unlock_state();
      return status;
}

/*
 * nfs4_unlock_state() called after encode
 */
__be32
nfsd4_close(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
          struct nfsd4_close *close)
{
      __be32 status;
      struct nfs4_stateid *stp;

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

      nfs4_lock_state();
      /* check close_lru for replay */
      if ((status = nfs4_preprocess_seqid_op(cstate,
                              close->cl_seqid,
                              &close->cl_stateid, 
                              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_open_stateid(stp);

      /* 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);
            cstate->replay_owner = close->cl_stateowner;
      }
      nfs4_unlock_state();
      return status;
}

__be32
nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
              struct nfsd4_delegreturn *dr)
{
      struct nfs4_delegation *dp;
      stateid_t *stateid = &dr->dr_stateid;
      struct inode *inode;
      __be32 status;
      int flags = 0;

      if ((status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0)))
            return status;
      inode = cstate->current_fh.fh_dentry->d_inode;

      if (nfsd4_has_session(cstate))
            flags |= HAS_SESSION;
      nfs4_lock_state();
      status = nfserr_bad_stateid;
      if (ZERO_STATEID(stateid) || ONE_STATEID(stateid))
            goto out;
      status = nfserr_stale_stateid;
      if (STALE_STATEID(stateid))
            goto out;
      status = nfserr_bad_stateid;
      if (!is_delegation_stateid(stateid))
            goto out;
      dp = find_delegation_stateid(inode, stateid);
      if (!dp) {
            status = stateid_error_map(stateid);
            goto out;
      }
      status = check_stateid_generation(stateid, &dp->dl_stateid, flags);
      if (status)
            goto out;
      renew_client(dp->dl_client);

      unhash_delegation(dp);
out:
      nfs4_unlock_state();

      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)

static inline u64
end_offset(u64 start, u64 len)
{
      u64 end;

      end = start + len;
      return end >= start ? end: NFS4_MAX_UINT64;
}

/* last octet in a range */
static inline u64
last_byte_offset(u64 start, u64 len)
{
      u64 end;

      BUG_ON(!len);
      end = start + len;
      return end > start ? end - 1: NFS4_MAX_UINT64;
}

#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;
      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 | RD_STATE | 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 | RD_STATE | 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 = NFS4_MAX_UINT64;
      if (fl->fl_end != NFS4_MAX_UINT64)
            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 (same_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 = get_seconds();
      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 != NFS4_MAX_UINT64) &&
           LOFF_OVERFLOW(offset, length)));
}

/*
 *  LOCK operation 
 */
__be32
nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         struct nfsd4_lock *lock)
{
      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;
      __be32 status = 0;
      unsigned int strhashval;
      unsigned int cmd;
      int err;

      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, &cstate->current_fh,
                        S_IFREG, NFSD_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 (!nfsd4_has_session(cstate) &&
                STALE_CLIENTID(&lock->lk_new_clientid))
                  goto out;

            /* validate and update open stateid and open seqid */
            status = nfs4_preprocess_seqid_op(cstate,
                                lock->lk_new_open_seqid,
                                    &lock->lk_new_open_stateid,
                              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(cstate,
                               lock->lk_old_lock_seqid, 
                               &lock->lk_old_lock_stateid, 
                               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 (locks_in_grace() && !lock->lk_reclaim)
            goto out;
      status = nfserr_no_grace;
      if (!locks_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;
                  cmd = F_SETLK;
            break;
            case NFS4_WRITE_LT:
            case NFS4_WRITEW_LT:
                  file_lock.fl_type = F_WRLCK;
                  cmd = F_SETLK;
            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;
      file_lock.fl_end = last_byte_offset(lock->lk_offset, lock->lk_length);
      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.
      */

      err = vfs_lock_file(filp, cmd, &file_lock, &conflock);
      switch (-err) {
      case 0: /* success! */
            update_stateid(&lock_stp->st_stateid);
            memcpy(&lock->lk_resp_stateid, &lock_stp->st_stateid, 
                        sizeof(stateid_t));
            status = 0;
            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: vfs_lock_file() failed! status %d\n",err);
            status = nfserr_resource;
            break;
      }
out:
      if (status && lock->lk_is_new && lock_sop)
            release_lockowner(lock_sop);
      if (lock->lk_replay_owner) {
            nfs4_get_stateowner(lock->lk_replay_owner);
            cstate->replay_owner = lock->lk_replay_owner;
      }
      nfs4_unlock_state();
      return status;
}

/*
 * The NFSv4 spec allows a client to do a LOCKT without holding an OPEN,
 * so we do a temporary open here just to get an open file to pass to
 * vfs_test_lock.  (Arguably perhaps test_lock should be done with an
 * inode operation.)
 */
static int nfsd_test_lock(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file_lock *lock)
{
      struct file *file;
      int err;

      err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);
      if (err)
            return err;
      err = vfs_test_lock(file, lock);
      nfsd_close(file);
      return err;
}

/*
 * LOCKT operation
 */
__be32
nfsd4_lockt(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
          struct nfsd4_lockt *lockt)
{
      struct inode *inode;
      struct file_lock file_lock;
      int error;
      __be32 status;

      if (locks_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 (!nfsd4_has_session(cstate) && STALE_CLIENTID(&lockt->lt_clientid))
            goto out;

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

      inode = cstate->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:
                  dprintk("NFSD: nfs4_lockt: bad lock type!\n");
                  status = nfserr_inval;
            goto out;
      }

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

      file_lock.fl_start = lockt->lt_offset;
      file_lock.fl_end = last_byte_offset(lockt->lt_offset, lockt->lt_length);

      nfs4_transform_lock_offset(&file_lock);

      status = nfs_ok;
      error = nfsd_test_lock(rqstp, &cstate->current_fh, &file_lock);
      if (error) {
            status = nfserrno(error);
            goto out;
      }
      if (file_lock.fl_type != F_UNLCK) {
            status = nfserr_denied;
            nfs4_set_lock_denied(&file_lock, &lockt->lt_denied);
      }
out:
      nfs4_unlock_state();
      return status;
}

__be32
nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
          struct nfsd4_locku *locku)
{
      struct nfs4_stateid *stp;
      struct file *filp = NULL;
      struct file_lock file_lock;
      __be32 status;
      int err;
                                            
      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(cstate,
                              locku->lu_seqid, 
                              &locku->lu_stateid, 
                              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;

      file_lock.fl_end = last_byte_offset(locku->lu_offset, locku->lu_length);
      nfs4_transform_lock_offset(&file_lock);

      /*
      *  Try to unlock the file in the VFS.
      */
      err = vfs_lock_file(filp, F_SETLK, &file_lock, NULL);
      if (err) {
            dprintk("NFSD: nfs4_locku: vfs_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);
            cstate->replay_owner = locku->lu_stateowner;
      }
      nfs4_unlock_state();
      return status;

out_nfserr:
      status = nfserrno(err);
      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_path.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;
}

__be32
nfsd4_release_lockowner(struct svc_rqst *rqstp,
                  struct nfsd4_compound_state *cstate,
                  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;
      __be32 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 (!same_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_lockowner(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, bool use_exchange_id)
{
      unsigned int strhashval = clientstr_hashval(name);
      struct nfs4_client *clp;

      clp = find_confirmed_client_by_str(name, strhashval, use_exchange_id);
      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.
*/
__be32
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: */

int
nfs4_state_init(void)
{
      int i, status;

      status = nfsd4_init_slabs();
      if (status)
            return status;
      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]);
            INIT_LIST_HEAD(&reclaim_str_hashtbl[i]);
      }
      for (i = 0; i < SESSION_HASH_SIZE; i++)
            INIT_LIST_HEAD(&sessionid_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);
      reclaim_str_hashtbl_size = 0;
      return 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");
}

unsigned long
get_nfs4_grace_period(void)
{
      return max(user_lease_time, lease_time) * HZ;
}

/*
 * Since the lifetime of a delegation isn't limited to that of an open, a
 * client may quite reasonably hang on to a delegation as long as it has
 * the inode cached.  This becomes an obvious problem the first time a
 * client's inode cache approaches the size of the server's total memory.
 *
 * For now we avoid this problem by imposing a hard limit on the number
 * of delegations, which varies according to the server's memory size.
 */
static void
set_max_delegations(void)
{
      /*
       * Allow at most 4 delegations per megabyte of RAM.  Quick
       * estimates suggest that in the worst case (where every delegation
       * is for a different inode), a delegation could take about 1.5K,
       * giving a worst case usage of about 6% of memory.
       */
      max_delegations = nr_free_buffer_pages() >> (20 - 2 - PAGE_SHIFT);
}

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

static void
__nfs4_state_start(void)
{
      unsigned long grace_time;

      boot_time = get_seconds();
      grace_time = get_nfs4_grace_period();
      lease_time = user_lease_time;
      locks_start_grace(&nfsd4_manager);
      printk(KERN_INFO "NFSD: starting %ld-second grace period\n",
             grace_time/HZ);
      laundry_wq = create_singlethread_workqueue("nfsd4");
      queue_delayed_work(laundry_wq, &laundromat_work, grace_time);
      set_max_delegations();
}

void
nfs4_state_start(void)
{
      if (nfs4_init)
            return;
      nfsd4_load_reboot_recovery_data();
      __nfs4_state_start();
      nfs4_init = 1;
      return;
}

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);
      }

      nfsd4_shutdown_recdir();
      nfs4_init = 0;
}

void
nfs4_state_shutdown(void)
{
      cancel_rearming_delayed_workqueue(laundry_wq, &laundromat_work);
      destroy_workqueue(laundry_wq);
      locks_end_grace(&nfsd4_manager);
      nfs4_lock_state();
      nfs4_release_reclaim();
      __nfs4_state_shutdown();
      nfs4_unlock_state();
}

/*
 * user_recovery_dirname is protected by the nfsd_mutex since it's only
 * accessed when nfsd is starting.
 */
static void
nfs4_set_recdir(char *recdir)
{
      strcpy(user_recovery_dirname, recdir);
}

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

      status = kern_path(recdir, LOOKUP_FOLLOW, &path);
      if (status)
            return status;
      status = -ENOTDIR;
      if (S_ISDIR(path.dentry->d_inode->i_mode)) {
            nfs4_set_recdir(recdir);
            status = 0;
      }
      path_put(&path);
      return status;
}

char *
nfs4_recoverydir(void)
{
      return user_recovery_dirname;
}

/*
 * 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.
 *
 * user_lease_time is protected by nfsd_mutex since it's only really accessed
 * when nfsd is starting
 */
void
nfs4_reset_lease(time_t leasetime)
{
      user_lease_time = leasetime;
}

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