path: root/xlators/performance/nl-cache/src/nl-cache.c

/*
 *   Copyright (c) 2016 Red Hat, Inc. <http://www.redhat.com>
 *   This file is part of GlusterFS.
 *
 *   This file is licensed to you under your choice of the GNU Lesser
 *   General Public License, version 3 or any later version (LGPLv3 or
 *   later), or the GNU General Public License, version 2 (GPLv2), in all
 *   cases as published by the Free Software Foundation.
 */

#include "nl-cache.h"
#include <glusterfs/statedump.h>
#include <glusterfs/upcall-utils.h>

static void
nlc_dentry_op(call_frame_t *frame, xlator_t *this, gf_boolean_t multilink)
{
    nlc_local_t *local = frame->local;

    GF_VALIDATE_OR_GOTO(this->name, local, out);

    switch (local->fop) {
        case GF_FOP_MKDIR:
            nlc_set_dir_state(this, local->loc.inode, NLC_PE_FULL);
            /*fall-through*/
        case GF_FOP_MKNOD:
        case GF_FOP_CREATE:
        case GF_FOP_SYMLINK:
            nlc_dir_add_pe(this, local->loc.parent, local->loc.inode,
                           local->loc.name);
            break;
        case GF_FOP_LINK:
            nlc_dir_add_pe(this, local->loc2.parent, NULL, local->loc2.name);
            break;
        case GF_FOP_RMDIR:
            nlc_inode_clear_cache(this, local->loc.inode, _gf_false);
            /*fall-through*/
        case GF_FOP_UNLINK:
            nlc_dir_remove_pe(this, local->loc.parent, local->loc.inode,
                              local->loc.name, multilink);
            break;
        case GF_FOP_RENAME:
            /* TBD: Should these be atomic ?  In case of rename, the
             * newloc->inode can be NULL, and hence use oldloc->inode */
            nlc_dir_remove_pe(this, local->loc2.parent, local->loc2.inode,
                              local->loc2.name, _gf_false);

            /*TODO: Remove old dentry from destination before adding this pe*/
            nlc_dir_add_pe(this, local->loc.parent, local->loc2.inode,
                           local->loc.name);

        default:
            return;
    }

    nlc_lru_prune(this, NULL);
out:
    return;
}

#define NLC_FOP(_name, _op, loc1, loc2, frame, this, args...)                  \
    do {                                                                       \
        nlc_local_t *__local = NULL;                                           \
        nlc_conf_t *conf = NULL;                                               \
                                                                               \
        conf = this->private;                                                  \
                                                                               \
        if (!IS_PEC_ENABLED(conf))                                             \
            goto disabled;                                                     \
                                                                               \
        __local = nlc_local_init(frame, this, _op, loc1, loc2);                \
        GF_VALIDATE_OR_GOTO(this->name, __local, err);                         \
                                                                               \
        STACK_WIND(frame, nlc_##_name##_cbk, FIRST_CHILD(this),                \
                   FIRST_CHILD(this)->fops->_name, args);                      \
        break;                                                                 \
    disabled:                                                                  \
        default_##_name##_resume(frame, this, args);                           \
        break;                                                                 \
    err:                                                                       \
        default_##_name##_failure_cbk(frame, ENOMEM);                          \
        break;                                                                 \
    } while (0)

#define NLC_FOP_CBK(_name, multilink, frame, cookie, this, op_ret, op_errno,   \
                    args...)                                                   \
    do {                                                                       \
        nlc_conf_t *conf = NULL;                                               \
                                                                               \
        if (op_ret != 0)                                                       \
            goto out;                                                          \
                                                                               \
        conf = this->private;                                                  \
                                                                               \
        if (op_ret < 0 || !IS_PEC_ENABLED(conf))                               \
            goto out;                                                          \
        nlc_dentry_op(frame, this, multilink);                                 \
    out:                                                                       \
        NLC_STACK_UNWIND(_name, frame, op_ret, op_errno, args);                \
    } while (0)

static int32_t
nlc_rename_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
               int32_t op_ret, int32_t op_errno, struct iatt *buf,
               struct iatt *preoldparent, struct iatt *postoldparent,
               struct iatt *prenewparent, struct iatt *postnewparent,
               dict_t *xdata)
{
    NLC_FOP_CBK(rename, _gf_false, frame, cookie, this, op_ret, op_errno, buf,
                preoldparent, postoldparent, prenewparent, postnewparent,
                xdata);
    return 0;
}

static int32_t
nlc_rename(call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc,
           dict_t *xdata)
{
    NLC_FOP(rename, GF_FOP_RENAME, newloc, oldloc, frame, this, oldloc, newloc,
            xdata);
    return 0;
}

static int32_t
nlc_mknod_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
              int32_t op_errno, inode_t *inode, struct iatt *buf,
              struct iatt *preparent, struct iatt *postparent, dict_t *xdata)
{
    NLC_FOP_CBK(mknod, _gf_false, frame, cookie, this, op_ret, op_errno, inode,
                buf, preparent, postparent, xdata);
    return 0;
}

static int32_t
nlc_mknod(call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
          dev_t rdev, mode_t umask, dict_t *xdata)
{
    NLC_FOP(mknod, GF_FOP_MKNOD, loc, NULL, frame, this, loc, mode, rdev, umask,
            xdata);
    return 0;
}

static int32_t
nlc_create_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
               int32_t op_ret, int32_t op_errno, fd_t *fd, inode_t *inode,
               struct iatt *buf, struct iatt *preparent,
               struct iatt *postparent, dict_t *xdata)
{
    NLC_FOP_CBK(create, _gf_false, frame, cookie, this, op_ret, op_errno, fd,
                inode, buf, preparent, postparent, xdata);
    return 0;
}

static int32_t
nlc_create(call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
           mode_t mode, mode_t umask, fd_t *fd, dict_t *xdata)
{
    NLC_FOP(create, GF_FOP_CREATE, loc, NULL, frame, this, loc, flags, mode,
            umask, fd, xdata);
    return 0;
}

static int32_t
nlc_mkdir_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
              int32_t op_errno, inode_t *inode, struct iatt *buf,
              struct iatt *preparent, struct iatt *postparent, dict_t *xdata)
{
    NLC_FOP_CBK(mkdir, _gf_false, frame, cookie, this, op_ret, op_errno, inode,
                buf, preparent, postparent, xdata);
    return 0;
}

static int32_t
nlc_mkdir(call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
          mode_t umask, dict_t *xdata)
{
    NLC_FOP(mkdir, GF_FOP_MKDIR, loc, NULL, frame, this, loc, mode, umask,
            xdata);
    return 0;
}

static int32_t
nlc_lookup_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
               int32_t op_ret, int32_t op_errno, inode_t *inode,
               struct iatt *buf, dict_t *xdata, struct iatt *postparent)
{
    nlc_local_t *local = NULL;
    nlc_conf_t *conf = NULL;

    local = frame->local;
    conf = this->private;

    if (!local)
        goto out;

    /* Donot add to pe, this may lead to duplicate entry and
     * requires search before adding if list of strings */
    if (op_ret < 0 && op_errno == ENOENT) {
        nlc_dir_add_ne(this, local->loc.parent, local->loc.name);
        GF_ATOMIC_INC(conf->nlc_counter.nlc_miss);
    }

out:
    NLC_STACK_UNWIND(lookup, frame, op_ret, op_errno, inode, buf, xdata,
                     postparent);
    return 0;
}

static int32_t
nlc_lookup(call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
{
    nlc_local_t *local = NULL;
    nlc_conf_t *conf = NULL;
    inode_t *inode = NULL;

    if (loc_is_nameless(loc))
        goto wind;

    local = nlc_local_init(frame, this, GF_FOP_LOOKUP, loc, NULL);
    if (!local)
        goto err;

    conf = this->private;

    inode = inode_grep(loc->inode->table, loc->parent, loc->name);
    if (inode) {
        inode_unref(inode);
        goto wind;
    }

    if (nlc_is_negative_lookup(this, loc)) {
        GF_ATOMIC_INC(conf->nlc_counter.nlc_hit);
        gf_msg_trace(this->name, 0,
                     "Serving negative lookup from "
                     "cache:%s",
                     loc->name);
        goto unwind;
    }

wind:
    STACK_WIND(frame, nlc_lookup_cbk, FIRST_CHILD(this),
               FIRST_CHILD(this)->fops->lookup, loc, xdata);
    return 0;
unwind:
    NLC_STACK_UNWIND(lookup, frame, -1, ENOENT, NULL, NULL, NULL, NULL);
    return 0;
err:
    NLC_STACK_UNWIND(lookup, frame, -1, ENOMEM, NULL, NULL, NULL, NULL);
    return 0;
}

static int32_t
nlc_rmdir_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
              int32_t op_errno, struct iatt *preparent, struct iatt *postparent,
              dict_t *xdata)
{
    NLC_FOP_CBK(rmdir, _gf_false, frame, cookie, this, op_ret, op_errno,
                preparent, postparent, xdata);
    return 0;
}

static int32_t
nlc_rmdir(call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
          dict_t *xdata)
{
    NLC_FOP(rmdir, GF_FOP_RMDIR, loc, NULL, frame, this, loc, flags, xdata);
    return 0;
}

static int32_t
nlc_getxattr_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                 int32_t op_ret, int32_t op_errno, dict_t *dict, dict_t *xdata)
{
    nlc_conf_t *conf = NULL;

    conf = this->private;
    GF_VALIDATE_OR_GOTO(this->name, conf, out);

    if (!IS_PEC_ENABLED(conf))
        goto out;

    if (op_ret < 0 && op_errno == ENOENT) {
        GF_ATOMIC_INC(conf->nlc_counter.getrealfilename_miss);
    }

out:
    NLC_STACK_UNWIND(getxattr, frame, op_ret, op_errno, dict, xdata);
    return 0;
}

static int32_t
nlc_getxattr(call_frame_t *frame, xlator_t *this, loc_t *loc, const char *key,
             dict_t *xdata)
{
    int32_t op_ret = -1;
    int32_t op_errno = 0;
    dict_t *dict = NULL;
    nlc_local_t *local = NULL;
    gf_boolean_t hit = _gf_false;
    const char *fname = NULL;
    nlc_conf_t *conf = NULL;

    conf = this->private;

    if (!IS_PEC_ENABLED(conf))
        goto wind;

    if (!key || (strncmp(key, GF_XATTR_GET_REAL_FILENAME_KEY,
                         SLEN(GF_XATTR_GET_REAL_FILENAME_KEY)) != 0))
        goto wind;

    local = nlc_local_init(frame, this, GF_FOP_GETXATTR, loc, NULL);
    if (!local)
        goto err;

    if (loc->inode && key) {
        dict = dict_new();
        if (!dict)
            goto err;

        fname = key + SLEN(GF_XATTR_GET_REAL_FILENAME_KEY);
        hit = nlc_get_real_file_name(this, loc, fname, &op_ret, &op_errno,
                                     dict);
        if (hit)
            goto unwind;
        else
            dict_unref(dict);
    }

    STACK_WIND(frame, nlc_getxattr_cbk, FIRST_CHILD(this),
               FIRST_CHILD(this)->fops->getxattr, loc, key, xdata);
    return 0;
wind:
    STACK_WIND(frame, default_getxattr_cbk, FIRST_CHILD(this),
               FIRST_CHILD(this)->fops->getxattr, loc, key, xdata);
    return 0;
unwind:
    GF_ATOMIC_INC(conf->nlc_counter.getrealfilename_hit);
    NLC_STACK_UNWIND(getxattr, frame, op_ret, op_errno, dict, NULL);
    dict_unref(dict);
    return 0;
err:
    NLC_STACK_UNWIND(getxattr, frame, -1, ENOMEM, NULL, NULL);
    return 0;
}

static int32_t
nlc_symlink_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                int32_t op_ret, int32_t op_errno, inode_t *inode,
                struct iatt *buf, struct iatt *preparent,
                struct iatt *postparent, dict_t *xdata)
{
    NLC_FOP_CBK(symlink, _gf_false, frame, cookie, this, op_ret, op_errno,
                inode, buf, preparent, postparent, xdata);
    return 0;
}

static int32_t
nlc_symlink(call_frame_t *frame, xlator_t *this, const char *linkpath,
            loc_t *loc, mode_t umask, dict_t *xdata)
{
    NLC_FOP(symlink, GF_FOP_SYMLINK, loc, NULL, frame, this, linkpath, loc,
            umask, xdata);
    return 0;
}

static int32_t
nlc_link_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
             int32_t op_errno, inode_t *inode, struct iatt *buf,
             struct iatt *preparent, struct iatt *postparent, dict_t *xdata)
{
    NLC_FOP_CBK(link, _gf_false, frame, cookie, this, op_ret, op_errno, inode,
                buf, preparent, postparent, xdata);
    return 0;
}

static int32_t
nlc_link(call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc,
         dict_t *xdata)
{
    NLC_FOP(link, GF_FOP_LINK, oldloc, newloc, frame, this, oldloc, newloc,
            xdata);
    return 0;
}

static int32_t
nlc_unlink_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
               int32_t op_ret, int32_t op_errno, struct iatt *preparent,
               struct iatt *postparent, dict_t *xdata)
{
    uint32_t link_count = 0;
    gf_boolean_t multilink = _gf_false;

    if (xdata && !dict_get_uint32(xdata, GET_LINK_COUNT, &link_count)) {
        if (link_count > 1)
            multilink = _gf_true;
    } else {
        /* Don't touch cache if we don't know enough */
        gf_msg(this->name, GF_LOG_WARNING, 0, NLC_MSG_DICT_FAILURE,
               "Failed to get GET_LINK_COUNT from dict");
        NLC_STACK_UNWIND(unlink, frame, op_ret, op_errno, preparent, postparent,
                         xdata);
        return 0;
    }

    NLC_FOP_CBK(unlink, multilink, frame, cookie, this, op_ret, op_errno,
                preparent, postparent, xdata);
    return 0;
}

static int32_t
nlc_unlink(call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
           dict_t *xdata)
{
    nlc_conf_t *conf = NULL;
    gf_boolean_t new_dict = _gf_false;

    conf = this->private;

    if (!IS_PEC_ENABLED(conf))
        goto do_fop;

    if (!xdata) {
        xdata = dict_new();
        if (xdata)
            new_dict = _gf_true;
    }

    if (xdata && dict_set_uint32(xdata, GET_LINK_COUNT, 0)) {
        gf_msg(this->name, GF_LOG_WARNING, 0, NLC_MSG_DICT_FAILURE,
               "Failed to set GET_LINK_COUNT in dict");
        goto err;
    }

do_fop:
    NLC_FOP(unlink, GF_FOP_UNLINK, loc, NULL, frame, this, loc, flags, xdata);

    if (new_dict)
        dict_unref(xdata);
    return 0;
}

static int32_t
nlc_invalidate(xlator_t *this, void *data)
{
    struct gf_upcall *up_data = NULL;
    struct gf_upcall_cache_invalidation *up_ci = NULL;
    inode_t *inode = NULL;
    inode_t *parent1 = NULL;
    inode_t *parent2 = NULL;
    int ret = 0;
    inode_table_t *itable = NULL;
    nlc_conf_t *conf = NULL;

    up_data = (struct gf_upcall *)data;

    if (up_data->event_type != GF_UPCALL_CACHE_INVALIDATION)
        goto out;

    conf = this->private;
    if (!conf)
        goto out;

    up_ci = (struct gf_upcall_cache_invalidation *)up_data->data;

    /*TODO: Add he inodes found as a member in gf_upcall_cache_invalidation
     * so that it prevents subsequent xlators from doing inode_find again
     */
    itable = ((xlator_t *)this->graph->top)->itable;
    inode = inode_find(itable, up_data->gfid);
    if (!inode) {
        ret = -1;
        goto out;
    }

    if ((!((up_ci->flags & UP_TIMES) && inode->ia_type == IA_IFDIR)) &&
        (!(up_ci->flags & UP_PARENT_DENTRY_FLAGS))) {
        goto out;
    }

    if (!gf_uuid_is_null(up_ci->p_stat.ia_gfid)) {
        parent1 = inode_find(itable, up_ci->p_stat.ia_gfid);
        if (!parent1) {
            ret = -1;
            goto out;
        }
    }

    if (!gf_uuid_is_null(up_ci->oldp_stat.ia_gfid)) {
        parent2 = inode_find(itable, up_ci->oldp_stat.ia_gfid);
        if (!parent2) {
            ret = -1;
            goto out;
        }
    }

    /* TODO: get enough data in upcall so that we do not invalidate but
     * update */
    if (inode && inode->ia_type == IA_IFDIR)
        nlc_inode_clear_cache(this, inode, NLC_NONE);
    if (parent1)
        nlc_inode_clear_cache(this, parent1, NLC_NONE);
    if (parent2)
        nlc_inode_clear_cache(this, parent2, NLC_NONE);

    GF_ATOMIC_INC(conf->nlc_counter.nlc_invals);

out:
    if (inode)
        inode_unref(inode);
    if (parent1)
        inode_unref(parent1);
    if (parent2)
        inode_unref(parent2);

    return ret;
}

int
nlc_notify(xlator_t *this, int event, void *data, ...)
{
    int ret = 0;
    time_t now = 0;

    switch (event) {
        case GF_EVENT_CHILD_DOWN:
        case GF_EVENT_SOME_DESCENDENT_DOWN:
        case GF_EVENT_CHILD_UP:
        case GF_EVENT_SOME_DESCENDENT_UP:
            time(&now);
            nlc_update_child_down_time(this, &now);
            /* TODO: nlc_clear_all_cache (this); else
             lru prune will lazily clear it*/
            break;
        case GF_EVENT_UPCALL:
            ret = nlc_invalidate(this, data);
            break;
        case GF_EVENT_PARENT_DOWN:
            nlc_disable_cache(this);
            nlc_clear_all_cache(this);
        default:
            break;
    }

    if (default_notify(this, event, data) != 0)
        ret = -1;

    return ret;
}

static int32_t
nlc_forget(xlator_t *this, inode_t *inode)
{
    uint64_t pe_int = 0;
    uint64_t nlc_ctx_int = 0;
    nlc_ctx_t *nlc_ctx = NULL;
    nlc_conf_t *conf = NULL;

    conf = this->private;

    inode_ctx_reset1(inode, this, &pe_int);
    GF_ASSERT(pe_int == 0);

    nlc_inode_clear_cache(this, inode, NLC_NONE);
    inode_ctx_reset0(inode, this, &nlc_ctx_int);
    nlc_ctx = (void *)(long)nlc_ctx_int;
    if (nlc_ctx) {
        GF_FREE(nlc_ctx);
        GF_ATOMIC_SUB(conf->current_cache_size, sizeof(*nlc_ctx));
    }

    return 0;
}

static int32_t
nlc_inodectx(xlator_t *this, inode_t *inode)
{
    nlc_dump_inodectx(this, inode);
    return 0;
}

static int32_t
nlc_priv_dump(xlator_t *this)
{
    nlc_conf_t *conf = NULL;
    char key_prefix[GF_DUMP_MAX_BUF_LEN];

    conf = this->private;

    snprintf(key_prefix, GF_DUMP_MAX_BUF_LEN, "%s.%s", this->type, this->name);
    gf_proc_dump_add_section("%s", key_prefix);

    gf_proc_dump_write("negative_lookup_hit_count", "%" PRId64,
                       GF_ATOMIC_GET(conf->nlc_counter.nlc_hit));
    gf_proc_dump_write("negative_lookup_miss_count", "%" PRId64,
                       GF_ATOMIC_GET(conf->nlc_counter.nlc_miss));
    gf_proc_dump_write("get_real_filename_hit_count", "%" PRId64,
                       GF_ATOMIC_GET(conf->nlc_counter.getrealfilename_hit));
    gf_proc_dump_write("get_real_filename_miss_count", "%" PRId64,
                       GF_ATOMIC_GET(conf->nlc_counter.getrealfilename_miss));
    gf_proc_dump_write("nameless_lookup_count", "%" PRId64,
                       GF_ATOMIC_GET(conf->nlc_counter.nameless_lookup));
    gf_proc_dump_write("inodes_with_positive_dentry_cache", "%" PRId64,
                       GF_ATOMIC_GET(conf->nlc_counter.pe_inode_cnt));
    gf_proc_dump_write("inodes_with_negative_dentry_cache", "%" PRId64,
                       GF_ATOMIC_GET(conf->nlc_counter.ne_inode_cnt));
    gf_proc_dump_write("dentry_invalidations_recieved", "%" PRId64,
                       GF_ATOMIC_GET(conf->nlc_counter.nlc_invals));
    gf_proc_dump_write("cache_limit", "%" PRIu64, conf->cache_size);
    gf_proc_dump_write("consumed_cache_size", "%" PRId64,
                       GF_ATOMIC_GET(conf->current_cache_size));
    gf_proc_dump_write("inode_limit", "%" PRIu64, conf->inode_limit);
    gf_proc_dump_write("consumed_inodes", "%" PRId64,
                       GF_ATOMIC_GET(conf->refd_inodes));

    return 0;
}

static int32_t
nlc_dump_metrics(xlator_t *this, int fd)
{
    nlc_conf_t *conf = NULL;

    conf = this->private;

    dprintf(fd, "%s.negative_lookup_hit_count %" PRId64 "\n", this->name,
            GF_ATOMIC_GET(conf->nlc_counter.nlc_hit));
    dprintf(fd, "%s.negative_lookup_miss_count %" PRId64 "\n", this->name,
            GF_ATOMIC_GET(conf->nlc_counter.nlc_miss));
    dprintf(fd, "%s.get_real_filename_hit_count %" PRId64 "\n", this->name,
            GF_ATOMIC_GET(conf->nlc_counter.getrealfilename_hit));
    dprintf(fd, "%s.get_real_filename_miss_count %" PRId64 "\n", this->name,
            GF_ATOMIC_GET(conf->nlc_counter.getrealfilename_miss));
    dprintf(fd, "%s.nameless_lookup_count %" PRId64 "\n", this->name,
            GF_ATOMIC_GET(conf->nlc_counter.nameless_lookup));
    dprintf(fd, "%s.inodes_with_positive_dentry_cache %" PRId64 "\n",
            this->name, GF_ATOMIC_GET(conf->nlc_counter.pe_inode_cnt));
    dprintf(fd, "%s.inodes_with_negative_dentry_cache %" PRId64 "\n",
            this->name, GF_ATOMIC_GET(conf->nlc_counter.ne_inode_cnt));
    dprintf(fd, "%s.dentry_invalidations_recieved %" PRId64 "\n", this->name,
            GF_ATOMIC_GET(conf->nlc_counter.nlc_invals));
    dprintf(fd, "%s.cache_limit %" PRIu64 "\n", this->name, conf->cache_size);
    dprintf(fd, "%s.consumed_cache_size %" PRId64 "\n", this->name,
            GF_ATOMIC_GET(conf->current_cache_size));
    dprintf(fd, "%s.inode_limit %" PRIu64 "\n", this->name, conf->inode_limit);
    dprintf(fd, "%s.consumed_inodes %" PRId64 "\n", this->name,
            GF_ATOMIC_GET(conf->refd_inodes));

    return 0;
}

void
nlc_fini(xlator_t *this)
{
    nlc_conf_t *conf = NULL;

    conf = this->private;
    GF_FREE(conf);

    glusterfs_ctx_tw_put(this->ctx);

    return;
}

int32_t
nlc_mem_acct_init(xlator_t *this)
{
    int ret = -1;

    ret = xlator_mem_acct_init(this, gf_nlc_mt_end + 1);
    return ret;
}

int32_t
nlc_reconfigure(xlator_t *this, dict_t *options)
{
    nlc_conf_t *conf = NULL;

    conf = this->private;

    GF_OPTION_RECONF("nl-cache-timeout", conf->cache_timeout, options, int32,
                     out);
    GF_OPTION_RECONF("nl-cache-positive-entry", conf->positive_entry_cache,
                     options, bool, out);
    GF_OPTION_RECONF("nl-cache-limit", conf->cache_size, options, size_uint64,
                     out);
    GF_OPTION_RECONF("pass-through", this->pass_through, options, bool, out);

out:
    return 0;
}

int32_t
nlc_init(xlator_t *this)
{
    nlc_conf_t *conf = NULL;
    int ret = -1;
    inode_table_t *itable = NULL;

    conf = GF_CALLOC(sizeof(*conf), 1, gf_nlc_mt_nlc_conf_t);
    if (!conf)
        goto out;

    GF_OPTION_INIT("nl-cache-timeout", conf->cache_timeout, int32, out);
    GF_OPTION_INIT("nl-cache-positive-entry", conf->positive_entry_cache, bool,
                   out);
    GF_OPTION_INIT("nl-cache-limit", conf->cache_size, size_uint64, out);
    GF_OPTION_INIT("pass-through", this->pass_through, bool, out);

    /* Since the positive entries are stored as list of refs on
     * existing inodes, we should not overflow the inode lru_limit.
     * Hence keep the limit of inodes that are refed by this xlator,
     * to 80% of inode_table->lru_limit. In fuse where the limit is
     * infinite, take 131072 as lru limit (as in gfapi). */
    itable = ((xlator_t *)this->graph->top)->itable;
    if (itable && itable->lru_limit)
        conf->inode_limit = itable->lru_limit * 80 / 100;
    else
        conf->inode_limit = 131072 * 80 / 100;

    LOCK_INIT(&conf->lock);
    GF_ATOMIC_INIT(conf->current_cache_size, 0);
    GF_ATOMIC_INIT(conf->refd_inodes, 0);
    GF_ATOMIC_INIT(conf->nlc_counter.nlc_hit, 0);
    GF_ATOMIC_INIT(conf->nlc_counter.nlc_miss, 0);
    GF_ATOMIC_INIT(conf->nlc_counter.nameless_lookup, 0);
    GF_ATOMIC_INIT(conf->nlc_counter.getrealfilename_hit, 0);
    GF_ATOMIC_INIT(conf->nlc_counter.getrealfilename_miss, 0);
    GF_ATOMIC_INIT(conf->nlc_counter.pe_inode_cnt, 0);
    GF_ATOMIC_INIT(conf->nlc_counter.ne_inode_cnt, 0);
    GF_ATOMIC_INIT(conf->nlc_counter.nlc_invals, 0);

    INIT_LIST_HEAD(&conf->lru);
    time(&conf->last_child_down);

    conf->timer_wheel = glusterfs_ctx_tw_get(this->ctx);
    if (!conf->timer_wheel) {
        gf_msg(this->name, GF_LOG_ERROR, 0, NLC_MSG_NO_TIMER_WHEEL,
               "Initing the global timer wheel failed");
        goto out;
    }

    this->private = conf;

    ret = 0;
out:
    if (ret < 0)
        GF_FREE(conf);

    return ret;
}

struct xlator_fops nlc_fops = {
    .rename = nlc_rename,
    .mknod = nlc_mknod,
    .create = nlc_create,
    .mkdir = nlc_mkdir,
    .lookup = nlc_lookup,
    .rmdir = nlc_rmdir,
    .getxattr = nlc_getxattr,
    .symlink = nlc_symlink,
    .link = nlc_link,
    .unlink = nlc_unlink,
    /* TODO:
    .readdir              = nlc_readdir,
    .readdirp             = nlc_readdirp,
    .seek                 = nlc_seek,
    .opendir              = nlc_opendir, */
};

struct xlator_cbks nlc_cbks = {
    .forget = nlc_forget,
};

struct xlator_dumpops nlc_dumpops = {
    .inodectx = nlc_inodectx,
    .priv = nlc_priv_dump,
};

struct volume_options nlc_options[] = {
    {
        .key = {"nl-cache"},
        .type = GF_OPTION_TYPE_BOOL,
        .default_value = "off",
        .description = "enable/disable nl-cache",
        .op_version = {GD_OP_VERSION_6_0},
        .flags = OPT_FLAG_SETTABLE,
    },
    {
        .key = {"nl-cache-positive-entry"},
        .type = GF_OPTION_TYPE_BOOL,
        .default_value = "false",
        .op_version = {GD_OP_VERSION_3_11_0},
        .flags = OPT_FLAG_SETTABLE | OPT_FLAG_CLIENT_OPT | OPT_FLAG_DOC,
        .description = "Cache the name of the files/directories that was"
                       " looked up and are present in a directory",
    },
    {
        .key = {"nl-cache-limit"},
        .type = GF_OPTION_TYPE_SIZET,
        .min = 0,
        .default_value = "131072",
        .op_version = {GD_OP_VERSION_3_11_0},
        .flags = OPT_FLAG_SETTABLE | OPT_FLAG_CLIENT_OPT | OPT_FLAG_DOC,
        .description = "the value over which caching will be disabled for"
                       "a while and the cache is cleared based on LRU",
    },
    {
        .key = {"nl-cache-timeout"},
        .type = GF_OPTION_TYPE_TIME,
        .min = 0,
        .default_value = "60",
        .op_version = {GD_OP_VERSION_3_11_0},
        .flags = OPT_FLAG_SETTABLE | OPT_FLAG_CLIENT_OPT | OPT_FLAG_DOC,
        .description = "Time period after which cache has to be refreshed",
    },
    {.key = {"pass-through"},
     .type = GF_OPTION_TYPE_BOOL,
     .default_value = "false",
     .op_version = {GD_OP_VERSION_4_1_0},
     .flags = OPT_FLAG_SETTABLE | OPT_FLAG_DOC | OPT_FLAG_CLIENT_OPT,
     .tags = {"nl-cache"},
     .description = "Enable/Disable nl cache translator"},

    {.key = {NULL}},
};

xlator_api_t xlator_api = {
    .init = nlc_init,
    .fini = nlc_fini,
    .notify = nlc_notify,
    .reconfigure = nlc_reconfigure,
    .mem_acct_init = nlc_mem_acct_init,
    .dump_metrics = nlc_dump_metrics,
    .op_version = {1}, /* Present from the initial version */
    .dumpops = &nlc_dumpops,
    .fops = &nlc_fops,
    .cbks = &nlc_cbks,
    .options = nlc_options,
    .identifier = "nl-cache",
    .category = GF_TECH_PREVIEW,
};