// SPDX-License-Identifier: GPL-2.0

  /*
   * Copyright (c) 2014 Christoph Hellwig.
   */

  #include <linux/blkdev.h>

  #include <linux/kmod.h>
  #include <linux/file.h>

  #include <linux/jhash.h>
  #include <linux/sched.h>

  #include <linux/sunrpc/addr.h>

  
  #include "pnfs.h"
  #include "netns.h"

  #include "trace.h"

  
  #define NFSDDBG_FACILITY                NFSDDBG_PNFS
  
  struct nfs4_layout {
  	struct list_head		lo_perstate;
  	struct nfs4_layout_stateid	*lo_state;
  	struct nfsd4_layout_seg		lo_seg;
  };
  
  static struct kmem_cache *nfs4_layout_cache;
  static struct kmem_cache *nfs4_layout_stateid_cache;

  static const struct nfsd4_callback_ops nfsd4_cb_layout_ops;

  static const struct lock_manager_operations nfsd4_layouts_lm_ops;

  const struct nfsd4_layout_ops *nfsd4_layout_ops[LAYOUT_TYPE_MAX] =  {

  #ifdef CONFIG_NFSD_FLEXFILELAYOUT
  	[LAYOUT_FLEX_FILES]	= &ff_layout_ops,
  #endif

  #ifdef CONFIG_NFSD_BLOCKLAYOUT

  	[LAYOUT_BLOCK_VOLUME]	= &bl_layout_ops,

  #endif

  #ifdef CONFIG_NFSD_SCSILAYOUT
  	[LAYOUT_SCSI]		= &scsi_layout_ops,
  #endif

  };
  
  /* pNFS device ID to export fsid mapping */
  #define DEVID_HASH_BITS	8
  #define DEVID_HASH_SIZE	(1 << DEVID_HASH_BITS)
  #define DEVID_HASH_MASK	(DEVID_HASH_SIZE - 1)
  static u64 nfsd_devid_seq = 1;
  static struct list_head nfsd_devid_hash[DEVID_HASH_SIZE];
  static DEFINE_SPINLOCK(nfsd_devid_lock);
  
  static inline u32 devid_hashfn(u64 idx)
  {
  	return jhash_2words(idx, idx >> 32, 0) & DEVID_HASH_MASK;
  }
  
  static void
  nfsd4_alloc_devid_map(const struct svc_fh *fhp)
  {
  	const struct knfsd_fh *fh = &fhp->fh_handle;
  	size_t fsid_len = key_len(fh->fh_fsid_type);
  	struct nfsd4_deviceid_map *map, *old;
  	int i;
  
  	map = kzalloc(sizeof(*map) + fsid_len, GFP_KERNEL);
  	if (!map)
  		return;
  
  	map->fsid_type = fh->fh_fsid_type;
  	memcpy(&map->fsid, fh->fh_fsid, fsid_len);
  
  	spin_lock(&nfsd_devid_lock);
  	if (fhp->fh_export->ex_devid_map)
  		goto out_unlock;
  
  	for (i = 0; i < DEVID_HASH_SIZE; i++) {
  		list_for_each_entry(old, &nfsd_devid_hash[i], hash) {
  			if (old->fsid_type != fh->fh_fsid_type)
  				continue;
  			if (memcmp(old->fsid, fh->fh_fsid,
  					key_len(old->fsid_type)))
  				continue;
  
  			fhp->fh_export->ex_devid_map = old;
  			goto out_unlock;
  		}
  	}
  
  	map->idx = nfsd_devid_seq++;
  	list_add_tail_rcu(&map->hash, &nfsd_devid_hash[devid_hashfn(map->idx)]);
  	fhp->fh_export->ex_devid_map = map;
  	map = NULL;
  
  out_unlock:
  	spin_unlock(&nfsd_devid_lock);
  	kfree(map);
  }
  
  struct nfsd4_deviceid_map *
  nfsd4_find_devid_map(int idx)
  {
  	struct nfsd4_deviceid_map *map, *ret = NULL;
  
  	rcu_read_lock();
  	list_for_each_entry_rcu(map, &nfsd_devid_hash[devid_hashfn(idx)], hash)
  		if (map->idx == idx)
  			ret = map;
  	rcu_read_unlock();
  
  	return ret;
  }
  
  int
  nfsd4_set_deviceid(struct nfsd4_deviceid *id, const struct svc_fh *fhp,
  		u32 device_generation)
  {
  	if (!fhp->fh_export->ex_devid_map) {
  		nfsd4_alloc_devid_map(fhp);
  		if (!fhp->fh_export->ex_devid_map)
  			return -ENOMEM;
  	}
  
  	id->fsid_idx = fhp->fh_export->ex_devid_map->idx;
  	id->generation = device_generation;
  	id->pad = 0;
  	return 0;
  }
  
  void nfsd4_setup_layout_type(struct svc_export *exp)
  {

  #if defined(CONFIG_NFSD_BLOCKLAYOUT) || defined(CONFIG_NFSD_SCSILAYOUT)

  	struct super_block *sb = exp->ex_path.mnt->mnt_sb;

  #endif

  	if (!(exp->ex_flags & NFSEXP_PNFS))

  		return;

  	/*

  	 * If flex file is configured, use it by default. Otherwise
  	 * check if the file system supports exporting a block-like layout.

  	 * If the block device supports reservations prefer the SCSI layout,
  	 * otherwise advertise the block layout.
  	 */

  #ifdef CONFIG_NFSD_FLEXFILELAYOUT

  	exp->ex_layout_types |= 1 << LAYOUT_FLEX_FILES;

  #endif

  #ifdef CONFIG_NFSD_BLOCKLAYOUT

  	/* overwrite flex file layout selection if needed */

  	if (sb->s_export_op->get_uuid &&
  	    sb->s_export_op->map_blocks &&
  	    sb->s_export_op->commit_blocks)

  		exp->ex_layout_types |= 1 << LAYOUT_BLOCK_VOLUME;

  #endif

  #ifdef CONFIG_NFSD_SCSILAYOUT
  	/* overwrite block layout selection if needed */
  	if (sb->s_export_op->map_blocks &&
  	    sb->s_export_op->commit_blocks &&
  	    sb->s_bdev && sb->s_bdev->bd_disk->fops->pr_ops)

  		exp->ex_layout_types |= 1 << LAYOUT_SCSI;

  #endif

  }
  
  static void
  nfsd4_free_layout_stateid(struct nfs4_stid *stid)
  {
  	struct nfs4_layout_stateid *ls = layoutstateid(stid);
  	struct nfs4_client *clp = ls->ls_stid.sc_client;
  	struct nfs4_file *fp = ls->ls_stid.sc_file;

  	trace_layoutstate_free(&ls->ls_stid.sc_stateid);

  	spin_lock(&clp->cl_lock);
  	list_del_init(&ls->ls_perclnt);
  	spin_unlock(&clp->cl_lock);
  
  	spin_lock(&fp->fi_lock);
  	list_del_init(&ls->ls_perfile);
  	spin_unlock(&fp->fi_lock);

  	if (!nfsd4_layout_ops[ls->ls_layout_type]->disable_recalls)
  		vfs_setlease(ls->ls_file, F_UNLCK, NULL, (void **)&ls);

  	fput(ls->ls_file);
  
  	if (ls->ls_recalled)
  		atomic_dec(&ls->ls_stid.sc_file->fi_lo_recalls);

  	kmem_cache_free(nfs4_layout_stateid_cache, ls);
  }

  static int
  nfsd4_layout_setlease(struct nfs4_layout_stateid *ls)
  {
  	struct file_lock *fl;
  	int status;

  	if (nfsd4_layout_ops[ls->ls_layout_type]->disable_recalls)
  		return 0;

  	fl = locks_alloc_lock();
  	if (!fl)
  		return -ENOMEM;
  	locks_init_lock(fl);
  	fl->fl_lmops = &nfsd4_layouts_lm_ops;
  	fl->fl_flags = FL_LAYOUT;
  	fl->fl_type = F_RDLCK;
  	fl->fl_end = OFFSET_MAX;
  	fl->fl_owner = ls;
  	fl->fl_pid = current->tgid;
  	fl->fl_file = ls->ls_file;
  
  	status = vfs_setlease(fl->fl_file, fl->fl_type, &fl, NULL);
  	if (status) {
  		locks_free_lock(fl);
  		return status;
  	}
  	BUG_ON(fl != NULL);
  	return 0;
  }

  static struct nfs4_layout_stateid *
  nfsd4_alloc_layout_stateid(struct nfsd4_compound_state *cstate,
  		struct nfs4_stid *parent, u32 layout_type)
  {
  	struct nfs4_client *clp = cstate->clp;
  	struct nfs4_file *fp = parent->sc_file;
  	struct nfs4_layout_stateid *ls;
  	struct nfs4_stid *stp;

  	stp = nfs4_alloc_stid(cstate->clp, nfs4_layout_stateid_cache,
  					nfsd4_free_layout_stateid);

  	if (!stp)
  		return NULL;

  	get_nfs4_file(fp);
  	stp->sc_file = fp;
  
  	ls = layoutstateid(stp);
  	INIT_LIST_HEAD(&ls->ls_perclnt);
  	INIT_LIST_HEAD(&ls->ls_perfile);
  	spin_lock_init(&ls->ls_lock);
  	INIT_LIST_HEAD(&ls->ls_layouts);

  	mutex_init(&ls->ls_mutex);

  	ls->ls_layout_type = layout_type;

  	nfsd4_init_cb(&ls->ls_recall, clp, &nfsd4_cb_layout_ops,
  			NFSPROC4_CLNT_CB_LAYOUT);
  
  	if (parent->sc_type == NFS4_DELEG_STID)
  		ls->ls_file = get_file(fp->fi_deleg_file);
  	else
  		ls->ls_file = find_any_file(fp);
  	BUG_ON(!ls->ls_file);
  
  	if (nfsd4_layout_setlease(ls)) {

  		fput(ls->ls_file);

  		put_nfs4_file(fp);
  		kmem_cache_free(nfs4_layout_stateid_cache, ls);
  		return NULL;
  	}

  
  	spin_lock(&clp->cl_lock);
  	stp->sc_type = NFS4_LAYOUT_STID;
  	list_add(&ls->ls_perclnt, &clp->cl_lo_states);
  	spin_unlock(&clp->cl_lock);
  
  	spin_lock(&fp->fi_lock);
  	list_add(&ls->ls_perfile, &fp->fi_lo_states);
  	spin_unlock(&fp->fi_lock);

  	trace_layoutstate_alloc(&ls->ls_stid.sc_stateid);

  	return ls;
  }
  
  __be32
  nfsd4_preprocess_layout_stateid(struct svc_rqst *rqstp,
  		struct nfsd4_compound_state *cstate, stateid_t *stateid,
  		bool create, u32 layout_type, struct nfs4_layout_stateid **lsp)
  {
  	struct nfs4_layout_stateid *ls;
  	struct nfs4_stid *stid;
  	unsigned char typemask = NFS4_LAYOUT_STID;
  	__be32 status;
  
  	if (create)
  		typemask |= (NFS4_OPEN_STID | NFS4_LOCK_STID | NFS4_DELEG_STID);
  
  	status = nfsd4_lookup_stateid(cstate, stateid, typemask, &stid,
  			net_generic(SVC_NET(rqstp), nfsd_net_id));
  	if (status)
  		goto out;
  
  	if (!fh_match(&cstate->current_fh.fh_handle,
  		      &stid->sc_file->fi_fhandle)) {
  		status = nfserr_bad_stateid;
  		goto out_put_stid;
  	}
  
  	if (stid->sc_type != NFS4_LAYOUT_STID) {
  		ls = nfsd4_alloc_layout_stateid(cstate, stid, layout_type);
  		nfs4_put_stid(stid);
  
  		status = nfserr_jukebox;
  		if (!ls)
  			goto out;

  		mutex_lock(&ls->ls_mutex);

  	} else {
  		ls = container_of(stid, struct nfs4_layout_stateid, ls_stid);
  
  		status = nfserr_bad_stateid;

  		mutex_lock(&ls->ls_mutex);

  		if (nfsd4_stateid_generation_after(stateid, &stid->sc_stateid))

  			goto out_unlock_stid;

  		if (layout_type != ls->ls_layout_type)

  			goto out_unlock_stid;

  	}
  
  	*lsp = ls;
  	return 0;

  out_unlock_stid:
  	mutex_unlock(&ls->ls_mutex);

  out_put_stid:
  	nfs4_put_stid(stid);
  out:
  	return status;
  }

  static void
  nfsd4_recall_file_layout(struct nfs4_layout_stateid *ls)
  {
  	spin_lock(&ls->ls_lock);
  	if (ls->ls_recalled)
  		goto out_unlock;
  
  	ls->ls_recalled = true;
  	atomic_inc(&ls->ls_stid.sc_file->fi_lo_recalls);
  	if (list_empty(&ls->ls_layouts))
  		goto out_unlock;

  	trace_layout_recall(&ls->ls_stid.sc_stateid);

  	atomic_inc(&ls->ls_stid.sc_count);

  	nfsd4_run_cb(&ls->ls_recall);
  
  out_unlock:
  	spin_unlock(&ls->ls_lock);
  }

  static inline u64
  layout_end(struct nfsd4_layout_seg *seg)
  {
  	u64 end = seg->offset + seg->length;
  	return end >= seg->offset ? end : NFS4_MAX_UINT64;
  }
  
  static void
  layout_update_len(struct nfsd4_layout_seg *lo, u64 end)
  {
  	if (end == NFS4_MAX_UINT64)
  		lo->length = NFS4_MAX_UINT64;
  	else
  		lo->length = end - lo->offset;
  }
  
  static bool
  layouts_overlapping(struct nfs4_layout *lo, struct nfsd4_layout_seg *s)
  {
  	if (s->iomode != IOMODE_ANY && s->iomode != lo->lo_seg.iomode)
  		return false;
  	if (layout_end(&lo->lo_seg) <= s->offset)
  		return false;
  	if (layout_end(s) <= lo->lo_seg.offset)
  		return false;
  	return true;
  }
  
  static bool
  layouts_try_merge(struct nfsd4_layout_seg *lo, struct nfsd4_layout_seg *new)
  {
  	if (lo->iomode != new->iomode)
  		return false;
  	if (layout_end(new) < lo->offset)
  		return false;
  	if (layout_end(lo) < new->offset)
  		return false;
  
  	lo->offset = min(lo->offset, new->offset);
  	layout_update_len(lo, max(layout_end(lo), layout_end(new)));
  	return true;
  }

  static __be32
  nfsd4_recall_conflict(struct nfs4_layout_stateid *ls)
  {
  	struct nfs4_file *fp = ls->ls_stid.sc_file;
  	struct nfs4_layout_stateid *l, *n;
  	__be32 nfserr = nfs_ok;
  
  	assert_spin_locked(&fp->fi_lock);
  
  	list_for_each_entry_safe(l, n, &fp->fi_lo_states, ls_perfile) {
  		if (l != ls) {
  			nfsd4_recall_file_layout(l);
  			nfserr = nfserr_recallconflict;
  		}
  	}
  
  	return nfserr;
  }

  __be32
  nfsd4_insert_layout(struct nfsd4_layoutget *lgp, struct nfs4_layout_stateid *ls)
  {
  	struct nfsd4_layout_seg *seg = &lgp->lg_seg;

  	struct nfs4_file *fp = ls->ls_stid.sc_file;

  	struct nfs4_layout *lp, *new = NULL;

  	__be32 nfserr;

  	spin_lock(&fp->fi_lock);
  	nfserr = nfsd4_recall_conflict(ls);
  	if (nfserr)
  		goto out;

  	spin_lock(&ls->ls_lock);
  	list_for_each_entry(lp, &ls->ls_layouts, lo_perstate) {
  		if (layouts_try_merge(&lp->lo_seg, seg))
  			goto done;
  	}
  	spin_unlock(&ls->ls_lock);

  	spin_unlock(&fp->fi_lock);

  
  	new = kmem_cache_alloc(nfs4_layout_cache, GFP_KERNEL);
  	if (!new)
  		return nfserr_jukebox;
  	memcpy(&new->lo_seg, seg, sizeof(lp->lo_seg));
  	new->lo_state = ls;

  	spin_lock(&fp->fi_lock);
  	nfserr = nfsd4_recall_conflict(ls);
  	if (nfserr)
  		goto out;

  	spin_lock(&ls->ls_lock);
  	list_for_each_entry(lp, &ls->ls_layouts, lo_perstate) {
  		if (layouts_try_merge(&lp->lo_seg, seg))
  			goto done;
  	}
  
  	atomic_inc(&ls->ls_stid.sc_count);
  	list_add_tail(&new->lo_perstate, &ls->ls_layouts);
  	new = NULL;
  done:

  	nfs4_inc_and_copy_stateid(&lgp->lg_sid, &ls->ls_stid);

  	spin_unlock(&ls->ls_lock);

  out:
  	spin_unlock(&fp->fi_lock);

  	if (new)
  		kmem_cache_free(nfs4_layout_cache, new);

  	return nfserr;

  }
  
  static void
  nfsd4_free_layouts(struct list_head *reaplist)
  {
  	while (!list_empty(reaplist)) {
  		struct nfs4_layout *lp = list_first_entry(reaplist,
  				struct nfs4_layout, lo_perstate);
  
  		list_del(&lp->lo_perstate);
  		nfs4_put_stid(&lp->lo_state->ls_stid);
  		kmem_cache_free(nfs4_layout_cache, lp);
  	}
  }
  
  static void
  nfsd4_return_file_layout(struct nfs4_layout *lp, struct nfsd4_layout_seg *seg,
  		struct list_head *reaplist)
  {
  	struct nfsd4_layout_seg *lo = &lp->lo_seg;
  	u64 end = layout_end(lo);
  
  	if (seg->offset <= lo->offset) {
  		if (layout_end(seg) >= end) {
  			list_move_tail(&lp->lo_perstate, reaplist);
  			return;
  		}

  		lo->offset = layout_end(seg);

  	} else {
  		/* retain the whole layout segment on a split. */
  		if (layout_end(seg) < end) {
  			dprintk("%s: split not supported
  ", __func__);
  			return;
  		}

  		end = seg->offset;

  	}
  
  	layout_update_len(lo, end);
  }
  
  __be32
  nfsd4_return_file_layouts(struct svc_rqst *rqstp,
  		struct nfsd4_compound_state *cstate,
  		struct nfsd4_layoutreturn *lrp)
  {
  	struct nfs4_layout_stateid *ls;
  	struct nfs4_layout *lp, *n;
  	LIST_HEAD(reaplist);
  	__be32 nfserr;
  	int found = 0;
  
  	nfserr = nfsd4_preprocess_layout_stateid(rqstp, cstate, &lrp->lr_sid,
  						false, lrp->lr_layout_type,
  						&ls);

  	if (nfserr) {
  		trace_layout_return_lookup_fail(&lrp->lr_sid);

  		return nfserr;

  	}

  
  	spin_lock(&ls->ls_lock);
  	list_for_each_entry_safe(lp, n, &ls->ls_layouts, lo_perstate) {
  		if (layouts_overlapping(lp, &lrp->lr_seg)) {
  			nfsd4_return_file_layout(lp, &lrp->lr_seg, &reaplist);
  			found++;
  		}
  	}
  	if (!list_empty(&ls->ls_layouts)) {

  		if (found)
  			nfs4_inc_and_copy_stateid(&lrp->lr_sid, &ls->ls_stid);

  		lrp->lrs_present = 1;
  	} else {

  		trace_layoutstate_unhash(&ls->ls_stid.sc_stateid);

  		nfs4_unhash_stid(&ls->ls_stid);
  		lrp->lrs_present = 0;
  	}
  	spin_unlock(&ls->ls_lock);

  	mutex_unlock(&ls->ls_mutex);

  	nfs4_put_stid(&ls->ls_stid);
  	nfsd4_free_layouts(&reaplist);
  	return nfs_ok;
  }
  
  __be32
  nfsd4_return_client_layouts(struct svc_rqst *rqstp,
  		struct nfsd4_compound_state *cstate,
  		struct nfsd4_layoutreturn *lrp)
  {
  	struct nfs4_layout_stateid *ls, *n;
  	struct nfs4_client *clp = cstate->clp;
  	struct nfs4_layout *lp, *t;
  	LIST_HEAD(reaplist);
  
  	lrp->lrs_present = 0;
  
  	spin_lock(&clp->cl_lock);
  	list_for_each_entry_safe(ls, n, &clp->cl_lo_states, ls_perclnt) {

  		if (ls->ls_layout_type != lrp->lr_layout_type)
  			continue;

  		if (lrp->lr_return_type == RETURN_FSID &&
  		    !fh_fsid_match(&ls->ls_stid.sc_file->fi_fhandle,
  				   &cstate->current_fh.fh_handle))
  			continue;
  
  		spin_lock(&ls->ls_lock);
  		list_for_each_entry_safe(lp, t, &ls->ls_layouts, lo_perstate) {
  			if (lrp->lr_seg.iomode == IOMODE_ANY ||
  			    lrp->lr_seg.iomode == lp->lo_seg.iomode)
  				list_move_tail(&lp->lo_perstate, &reaplist);
  		}
  		spin_unlock(&ls->ls_lock);
  	}
  	spin_unlock(&clp->cl_lock);
  
  	nfsd4_free_layouts(&reaplist);
  	return 0;
  }
  
  static void
  nfsd4_return_all_layouts(struct nfs4_layout_stateid *ls,
  		struct list_head *reaplist)
  {
  	spin_lock(&ls->ls_lock);
  	list_splice_init(&ls->ls_layouts, reaplist);
  	spin_unlock(&ls->ls_lock);
  }
  
  void
  nfsd4_return_all_client_layouts(struct nfs4_client *clp)
  {
  	struct nfs4_layout_stateid *ls, *n;
  	LIST_HEAD(reaplist);
  
  	spin_lock(&clp->cl_lock);
  	list_for_each_entry_safe(ls, n, &clp->cl_lo_states, ls_perclnt)
  		nfsd4_return_all_layouts(ls, &reaplist);
  	spin_unlock(&clp->cl_lock);
  
  	nfsd4_free_layouts(&reaplist);
  }
  
  void
  nfsd4_return_all_file_layouts(struct nfs4_client *clp, struct nfs4_file *fp)
  {
  	struct nfs4_layout_stateid *ls, *n;
  	LIST_HEAD(reaplist);
  
  	spin_lock(&fp->fi_lock);
  	list_for_each_entry_safe(ls, n, &fp->fi_lo_states, ls_perfile) {
  		if (ls->ls_stid.sc_client == clp)
  			nfsd4_return_all_layouts(ls, &reaplist);
  	}
  	spin_unlock(&fp->fi_lock);
  
  	nfsd4_free_layouts(&reaplist);
  }

  static void
  nfsd4_cb_layout_fail(struct nfs4_layout_stateid *ls)
  {
  	struct nfs4_client *clp = ls->ls_stid.sc_client;
  	char addr_str[INET6_ADDRSTRLEN];

  	static char const nfsd_recall_failed[] = "/sbin/nfsd-recall-failed";

  	static char *envp[] = {
  		"HOME=/",
  		"TERM=linux",
  		"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
  		NULL
  	};
  	char *argv[8];
  	int error;
  
  	rpc_ntop((struct sockaddr *)&clp->cl_addr, addr_str, sizeof(addr_str));
  
  	printk(KERN_WARNING
  		"nfsd: client %s failed to respond to layout recall. "
  		"  Fencing..
  ", addr_str);

  	argv[0] = (char *)nfsd_recall_failed;

  	argv[1] = addr_str;
  	argv[2] = ls->ls_file->f_path.mnt->mnt_sb->s_id;
  	argv[3] = NULL;

  	error = call_usermodehelper(nfsd_recall_failed, argv, envp,
  				    UMH_WAIT_PROC);

  	if (error) {
  		printk(KERN_ERR "nfsd: fence failed for client %s: %d!
  ",
  			addr_str, error);
  	}
  }

  static void
  nfsd4_cb_layout_prepare(struct nfsd4_callback *cb)
  {
  	struct nfs4_layout_stateid *ls =
  		container_of(cb, struct nfs4_layout_stateid, ls_recall);
  
  	mutex_lock(&ls->ls_mutex);

  	nfs4_inc_and_copy_stateid(&ls->ls_recall_sid, &ls->ls_stid);

  	mutex_unlock(&ls->ls_mutex);

  }

  static int
  nfsd4_cb_layout_done(struct nfsd4_callback *cb, struct rpc_task *task)
  {
  	struct nfs4_layout_stateid *ls =
  		container_of(cb, struct nfs4_layout_stateid, ls_recall);

  	struct nfsd_net *nn;
  	ktime_t now, cutoff;

  	const struct nfsd4_layout_ops *ops;

  	LIST_HEAD(reaplist);

  	switch (task->tk_status) {
  	case 0:

  	case -NFS4ERR_DELAY:
  		/*
  		 * Anything left? If not, then call it done. Note that we don't
  		 * take the spinlock since this is an optimization and nothing
  		 * should get added until the cb counter goes to zero.
  		 */
  		if (list_empty(&ls->ls_layouts))
  			return 1;
  
  		/* Poll the client until it's done with the layout */
  		now = ktime_get();
  		nn = net_generic(ls->ls_stid.sc_client->net, nfsd_net_id);
  
  		/* Client gets 2 lease periods to return it */
  		cutoff = ktime_add_ns(task->tk_start,
  					 nn->nfsd4_lease * NSEC_PER_SEC * 2);
  
  		if (ktime_before(now, cutoff)) {
  			rpc_delay(task, HZ/100); /* 10 mili-seconds */
  			return 0;
  		}
  		/* Fallthrough */

  	default:
  		/*
  		 * Unknown error or non-responding client, we'll need to fence.
  		 */

  		trace_layout_recall_fail(&ls->ls_stid.sc_stateid);
  
  		ops = nfsd4_layout_ops[ls->ls_layout_type];
  		if (ops->fence_client)
  			ops->fence_client(ls);
  		else
  			nfsd4_cb_layout_fail(ls);

  		return -1;

  	case -NFS4ERR_NOMATCHING_LAYOUT:
  		trace_layout_recall_done(&ls->ls_stid.sc_stateid);
  		task->tk_status = 0;
  		return 1;

  	}
  }
  
  static void
  nfsd4_cb_layout_release(struct nfsd4_callback *cb)
  {
  	struct nfs4_layout_stateid *ls =
  		container_of(cb, struct nfs4_layout_stateid, ls_recall);
  	LIST_HEAD(reaplist);

  	trace_layout_recall_release(&ls->ls_stid.sc_stateid);

  	nfsd4_return_all_layouts(ls, &reaplist);
  	nfsd4_free_layouts(&reaplist);
  	nfs4_put_stid(&ls->ls_stid);
  }

  static const struct nfsd4_callback_ops nfsd4_cb_layout_ops = {

  	.prepare	= nfsd4_cb_layout_prepare,

  	.done		= nfsd4_cb_layout_done,
  	.release	= nfsd4_cb_layout_release,
  };
  
  static bool
  nfsd4_layout_lm_break(struct file_lock *fl)
  {
  	/*
  	 * We don't want the locks code to timeout the lease for us;
  	 * we'll remove it ourself if a layout isn't returned
  	 * in time:
  	 */
  	fl->fl_break_time = 0;
  	nfsd4_recall_file_layout(fl->fl_owner);
  	return false;
  }
  
  static int
  nfsd4_layout_lm_change(struct file_lock *onlist, int arg,
  		struct list_head *dispose)
  {
  	BUG_ON(!(arg & F_UNLCK));
  	return lease_modify(onlist, arg, dispose);
  }
  
  static const struct lock_manager_operations nfsd4_layouts_lm_ops = {
  	.lm_break	= nfsd4_layout_lm_break,
  	.lm_change	= nfsd4_layout_lm_change,
  };

  int
  nfsd4_init_pnfs(void)
  {
  	int i;
  
  	for (i = 0; i < DEVID_HASH_SIZE; i++)
  		INIT_LIST_HEAD(&nfsd_devid_hash[i]);
  
  	nfs4_layout_cache = kmem_cache_create("nfs4_layout",
  			sizeof(struct nfs4_layout), 0, 0, NULL);
  	if (!nfs4_layout_cache)
  		return -ENOMEM;
  
  	nfs4_layout_stateid_cache = kmem_cache_create("nfs4_layout_stateid",
  			sizeof(struct nfs4_layout_stateid), 0, 0, NULL);
  	if (!nfs4_layout_stateid_cache) {
  		kmem_cache_destroy(nfs4_layout_cache);
  		return -ENOMEM;
  	}
  	return 0;
  }
  
  void
  nfsd4_exit_pnfs(void)
  {
  	int i;
  
  	kmem_cache_destroy(nfs4_layout_cache);
  	kmem_cache_destroy(nfs4_layout_stateid_cache);
  
  	for (i = 0; i < DEVID_HASH_SIZE; i++) {
  		struct nfsd4_deviceid_map *map, *n;
  
  		list_for_each_entry_safe(map, n, &nfsd_devid_hash[i], hash)
  			kfree(map);
  	}
  }