// 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 lease_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_fsid(fh), 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_fsid(fh),
                                        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;
        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;

#ifdef CONFIG_NFSD_FLEXFILELAYOUT
        exp->ex_layout_types |= 1 << LAYOUT_FLEX_FILES;
#endif
#ifdef CONFIG_NFSD_BLOCKLAYOUT
        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
        if (sb->s_export_op->map_blocks &&
            sb->s_export_op->commit_blocks &&
            sb->s_bdev &&
            sb->s_bdev->bd_disk->fops->pr_ops &&
            sb->s_bdev->bd_disk->fops->get_unique_id)
                exp->ex_layout_types |= 1 << LAYOUT_SCSI;
#endif
}

void nfsd4_close_layout(struct nfs4_layout_stateid *ls)
{
        struct nfsd_file *fl;

        spin_lock(&ls->ls_stid.sc_file->fi_lock);
        fl = ls->ls_file;
        ls->ls_file = NULL;
        spin_unlock(&ls->ls_stid.sc_file->fi_lock);

        if (fl) {
                if (!nfsd4_layout_ops[ls->ls_layout_type]->disable_recalls)
                        kernel_setlease(fl->nf_file, F_UNLCK, NULL,
                                        (void **)&ls);
                nfsd_file_put(fl);
        }
}

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_nfsd_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);

        nfsd4_close_layout(ls);

        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_lease *fl;
        int status;

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

        fl = locks_alloc_lease();
        if (!fl)
                return -ENOMEM;
        locks_init_lease(fl);
        fl->fl_lmops = &nfsd4_layouts_lm_ops;
        fl->c.flc_flags = FL_LAYOUT;
        fl->c.flc_type = F_RDLCK;
        fl->c.flc_owner = ls;
        fl->c.flc_pid = current->tgid;
        fl->c.flc_file = ls->ls_file->nf_file;

        status = kernel_setlease(fl->c.flc_file, fl->c.flc_type, &fl, NULL);
        if (status) {
                locks_free_lease(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 == SC_TYPE_DELEG)
                ls->ls_file = nfsd_file_get(fp->fi_deleg_file);
        else
                ls->ls_file = find_any_file(fp);
        BUG_ON(!ls->ls_file);

        if (nfsd4_layout_setlease(ls)) {
                nfsd_file_put(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 = SC_TYPE_LAYOUT;
        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_nfsd_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 short typemask = SC_TYPE_LAYOUT;
        __be32 status;

        if (create)
                typemask |= (SC_TYPE_OPEN | SC_TYPE_LOCK | SC_TYPE_DELEG);

        status = nfsd4_lookup_stateid(cstate, stateid, typemask, 0, &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 != SC_TYPE_LAYOUT) {
                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;

        if (list_empty(&ls->ls_layouts))
                goto out_unlock;

        ls->ls_recalled = true;
        atomic_inc(&ls->ls_stid.sc_file->fi_lo_recalls);
        trace_nfsd_layout_recall(&ls->ls_stid.sc_stateid);

        if (!test_and_set_bit(NFSD4_CALLBACK_RUNNING, &ls->ls_recall.cb_flags)) {
                refcount_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(new->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;
        }

        refcount_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\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_nfsd_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 = true;
        } else {
                trace_nfsd_layoutstate_unhash(&ls->ls_stid.sc_stateid);
                ls->ls_stid.sc_status |= SC_STATUS_CLOSED;
                lrp->lrs_present = false;
        }
        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 = false;

        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 nfsd_file *file)
{
        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..\n", addr_str);

        argv[0] = (char *)nfsd_recall_failed;
        argv[1] = addr_str;
        argv[2] = file->nf_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!\n",
                        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;
        struct nfsd_file *fl;

        trace_nfsd_cb_layout_done(&ls->ls_stid.sc_stateid, task);
        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,
                                         (u64)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_nfsd_layout_recall_fail(&ls->ls_stid.sc_stateid);
                rcu_read_lock();
                fl = nfsd_file_get(ls->ls_file);
                rcu_read_unlock();
                if (fl) {
                        ops = nfsd4_layout_ops[ls->ls_layout_type];
                        if (ops->fence_client)
                                ops->fence_client(ls, fl);
                        else
                                nfsd4_cb_layout_fail(ls, fl);
                        nfsd_file_put(fl);
                }
                return 1;
        case -NFS4ERR_NOMATCHING_LAYOUT:
                trace_nfsd_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_nfsd_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,
        .opcode         = OP_CB_LAYOUTRECALL,
};

static bool
nfsd4_layout_lm_break(struct file_lease *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->c.flc_owner);
        return false;
}

static int
nfsd4_layout_lm_change(struct file_lease *onlist, int arg,
                struct list_head *dispose)
{
        BUG_ON(!(arg & F_UNLCK));
        return lease_modify(onlist, arg, dispose);
}

/**
 *  nfsd4_layout_lm_open_conflict - see if the given file points to an inode that has
 *                                  an existing open that would conflict with the
 *                                  desired lease.
 * @filp:       file to check
 * @arg:        type of lease that we're trying to acquire
 *
 * The kernel will call into this operation to determine whether there
 * are conflicting opens that may prevent the layout from being granted.
 * For nfsd, that check is done at a higher level, so this trivially
 * returns 0.
 */
static int
nfsd4_layout_lm_open_conflict(struct file *filp, int arg)
{
        return 0;
}

static const struct lease_manager_operations nfsd4_layouts_lm_ops = {
        .lm_break               = nfsd4_layout_lm_break,
        .lm_change              = nfsd4_layout_lm_change,
        .lm_open_conflict       = nfsd4_layout_lm_open_conflict,
};

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(nfs4_layout, 0);
        if (!nfs4_layout_cache)
                return -ENOMEM;

        nfs4_layout_stateid_cache = KMEM_CACHE(nfs4_layout_stateid, 0);
        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);
        }
}