fs/nfsd/nfs4layouts.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (c) 2014 Christoph Hellwig.
  */
 #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 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] =  {
 	[LAYOUT_BLOCK_VOLUME]	= &bl_layout_ops,
 };

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

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

 	if (sb->s_export_op->get_uuid &&
 	    sb->s_export_op->map_blocks &&
 	    sb->s_export_op->commit_blocks)
 		exp->ex_layout_type = LAYOUT_BLOCK_VOLUME;
 }

 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);

 	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;

 	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);
 	if (!stp)
 		return NULL;
 	stp->sc_free = nfsd4_free_layout_stateid;
 	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);
 	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)) {
 		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;
 	} else {
 		ls = container_of(stid, struct nfs4_layout_stateid, ls_stid);

 		status = nfserr_bad_stateid;
 		if (stateid->si_generation > stid->sc_stateid.si_generation)
 			goto out_put_stid;
 		if (layout_type != ls->ls_layout_type)
 			goto out_put_stid;
 	}

 	*lsp = ls;
 	return 0;

 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);
 	update_stateid(&ls->ls_stid.sc_stateid);
 	memcpy(&ls->ls_recall_sid, &ls->ls_stid.sc_stateid, sizeof(stateid_t));
 	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:
 	update_stateid(&ls->ls_stid.sc_stateid);
 	memcpy(&lgp->lg_sid, &ls->ls_stid.sc_stateid, sizeof(stateid_t));
 	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\n", __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) {
 			update_stateid(&ls->ls_stid.sc_stateid);
 			memcpy(&lrp->lr_sid, &ls->ls_stid.sc_stateid,
 				sizeof(stateid_t));
 		}
 		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);

 	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 *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));

 	trace_layout_recall_fail(&ls->ls_stid.sc_stateid);

 	printk(KERN_WARNING
 		"nfsd: client %s failed to respond to layout recall. "
 		"  Fencing..\n", addr_str);

 	argv[0] = "/sbin/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(argv[0], argv, envp, UMH_WAIT_PROC);
 	if (error) {
 		printk(KERN_ERR "nfsd: fence failed for client %s: %d!\n",
 			addr_str, error);
 	}
 }

 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);
 	LIST_HEAD(reaplist);

 	switch (task->tk_status) {
 	case 0:
 		return 1;
 	case -NFS4ERR_NOMATCHING_LAYOUT:
 		trace_layout_recall_done(&ls->ls_stid.sc_stateid);
 		task->tk_status = 0;
 		return 1;
 	case -NFS4ERR_DELAY:
 		/* Poll the client until it's done with the layout */
 		/* FIXME: cap number of retries.
 		 * The pnfs standard states that we need to only expire
 		 * the client after at-least "lease time" .eg lease-time * 2
 		 * when failing to communicate a recall
 		 */
 		rpc_delay(task, HZ/100); /* 10 mili-seconds */
 		return 0;
 	default:
 		/*
 		 * Unknown error or non-responding client, we'll need to fence.
 		 */
 		nfsd4_cb_layout_fail(ls);
 		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 struct nfsd4_callback_ops nfsd4_cb_layout_ops = {
 	.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);
 	}
 }
	/*
	* Copyright (c) 2014 Christoph Hellwig.
	*/
	#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 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] = {
	[LAYOUT_BLOCK_VOLUME] = &bl_layout_ops,
	};

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

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

	if (sb->s_export_op->get_uuid &&
	sb->s_export_op->map_blocks &&
	sb->s_export_op->commit_blocks)
	exp->ex_layout_type = LAYOUT_BLOCK_VOLUME;
	}

	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);

	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;

	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);
	if (!stp)
	return NULL;
	stp->sc_free = nfsd4_free_layout_stateid;
	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);
	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)) {
	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;
	} else {
	ls = container_of(stid, struct nfs4_layout_stateid, ls_stid);

	status = nfserr_bad_stateid;
	if (stateid->si_generation > stid->sc_stateid.si_generation)
	goto out_put_stid;
	if (layout_type != ls->ls_layout_type)
	goto out_put_stid;
	}

	*lsp = ls;
	return 0;

	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);
	update_stateid(&ls->ls_stid.sc_stateid);
	memcpy(&ls->ls_recall_sid, &ls->ls_stid.sc_stateid, sizeof(stateid_t));
	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:
	update_stateid(&ls->ls_stid.sc_stateid);
	memcpy(&lgp->lg_sid, &ls->ls_stid.sc_stateid, sizeof(stateid_t));
	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\n", __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) {
	update_stateid(&ls->ls_stid.sc_stateid);
	memcpy(&lrp->lr_sid, &ls->ls_stid.sc_stateid,
	sizeof(stateid_t));
	}
	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);

	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 *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));

	trace_layout_recall_fail(&ls->ls_stid.sc_stateid);

	printk(KERN_WARNING
	"nfsd: client %s failed to respond to layout recall. "
	" Fencing..\n", addr_str);

	argv[0] = "/sbin/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(argv[0], argv, envp, UMH_WAIT_PROC);
	if (error) {
	printk(KERN_ERR "nfsd: fence failed for client %s: %d!\n",
	addr_str, error);
	}
	}

	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);
	LIST_HEAD(reaplist);

	switch (task->tk_status) {
	case 0:
	return 1;
	case -NFS4ERR_NOMATCHING_LAYOUT:
	trace_layout_recall_done(&ls->ls_stid.sc_stateid);
	task->tk_status = 0;
	return 1;
	case -NFS4ERR_DELAY:
	/* Poll the client until it's done with the layout */
	/* FIXME: cap number of retries.
	* The pnfs standard states that we need to only expire
	* the client after at-least "lease time" .eg lease-time * 2
	* when failing to communicate a recall
	*/
	rpc_delay(task, HZ/100); /* 10 mili-seconds */
	return 0;
	default:
	/*
	* Unknown error or non-responding client, we'll need to fence.
	*/
	nfsd4_cb_layout_fail(ls);
	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 struct nfsd4_callback_ops nfsd4_cb_layout_ops = {
	.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);
	}
	}