/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/lustre/llite/llite_nfs.c
 *
 * NFS export of Lustre Light File System
 *
 * Author: Yury Umanets <umka@clusterfs.com>
 * Author: Huang Hua <huanghua@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_LLITE
#include "../include/lustre_lite.h"
#include "llite_internal.h"
#include <linux/exportfs.h>

__u32 get_uuid2int(const char *name, int len)
{
        __u32 key0 = 0x12a3fe2d, key1 = 0x37abe8f9;
        while (len--) {
                __u32 key = key1 + (key0 ^ (*name++ * 7152373));

                if (key & 0x80000000)
                        key -= 0x7fffffff;
                key1 = key0;
                key0 = key;
        }
        return (key0 << 1);
}

void get_uuid2fsid(const char *name, int len, __kernel_fsid_t *fsid)
{
        __u64 key = 0, key0 = 0x12a3fe2d, key1 = 0x37abe8f9;

        while (len--) {
                key = key1 + (key0 ^ (*name++ * 7152373));
                if (key & 0x8000000000000000ULL)
                        key -= 0x7fffffffffffffffULL;
                key1 = key0;
                key0 = key;
        }

        fsid->val[0] = key;
        fsid->val[1] = key >> 32;
}

static int ll_nfs_test_inode(struct inode *inode, void *opaque)
{
        return lu_fid_eq(&ll_i2info(inode)->lli_fid,
                         (struct lu_fid *)opaque);
}

struct inode *search_inode_for_lustre(struct super_block *sb,
                                      const struct lu_fid *fid)
{
        struct ll_sb_info     *sbi = ll_s2sbi(sb);
        struct ptlrpc_request *req = NULL;
        struct inode      *inode = NULL;
        int                eadatalen = 0;
        unsigned long         hash = cl_fid_build_ino(fid,
                                                      ll_need_32bit_api(sbi));
        struct  md_op_data    *op_data;
        int                rc;

        CDEBUG(D_INFO, "searching inode for:(%lu,"DFID")\n", hash, PFID(fid));

        inode = ilookup5(sb, hash, ll_nfs_test_inode, (void *)fid);
        if (inode)
                return inode;

        rc = ll_get_default_mdsize(sbi, &eadatalen);
        if (rc)
                return ERR_PTR(rc);

        /* Because inode is NULL, ll_prep_md_op_data can not
         * be used here. So we allocate op_data ourselves */
        op_data = kzalloc(sizeof(*op_data), GFP_NOFS);
        if (!op_data)
                return ERR_PTR(-ENOMEM);

        op_data->op_fid1 = *fid;
        op_data->op_mode = eadatalen;
        op_data->op_valid = OBD_MD_FLEASIZE;

        /* mds_fid2dentry ignores f_type */
        rc = md_getattr(sbi->ll_md_exp, op_data, &req);
        OBD_FREE_PTR(op_data);
        if (rc) {
                CERROR("can't get object attrs, fid "DFID", rc %d\n",
                       PFID(fid), rc);
                return ERR_PTR(rc);
        }
        rc = ll_prep_inode(&inode, req, sb, NULL);
        ptlrpc_req_finished(req);
        if (rc)
                return ERR_PTR(rc);

        return inode;
}

struct lustre_nfs_fid {
        struct lu_fid   lnf_child;
        struct lu_fid   lnf_parent;
};

static struct dentry *
ll_iget_for_nfs(struct super_block *sb, struct lu_fid *fid, struct lu_fid *parent)
{
        struct inode  *inode;
        struct dentry *result;

        CDEBUG(D_INFO, "Get dentry for fid: "DFID"\n", PFID(fid));
        if (!fid_is_sane(fid))
                return ERR_PTR(-ESTALE);

        inode = search_inode_for_lustre(sb, fid);
        if (IS_ERR(inode))
                return ERR_CAST(inode);

        if (is_bad_inode(inode)) {
                /* we didn't find the right inode.. */
                iput(inode);
                return ERR_PTR(-ESTALE);
        }

        /**
         * It is an anonymous dentry without OST objects created yet.
         * We have to find the parent to tell MDS how to init lov objects.
         */
        if (S_ISREG(inode->i_mode) && !ll_i2info(inode)->lli_has_smd &&
            parent != NULL) {
                struct ll_inode_info *lli = ll_i2info(inode);

                spin_lock(&lli->lli_lock);
                lli->lli_pfid = *parent;
                spin_unlock(&lli->lli_lock);
        }

        result = d_obtain_alias(inode);
        if (IS_ERR(result)) {
                iput(inode);
                return result;
        }

        return result;
}

#define LUSTRE_NFS_FID    0x97

/**
 * \a connectable - is nfsd will connect himself or this should be done
 *                at lustre
 *
 * The return value is file handle type:
 * 1 -- contains child file handle;
 * 2 -- contains child file handle and parent file handle;
 * 255 -- error.
 */
static int ll_encode_fh(struct inode *inode, __u32 *fh, int *plen,
                        struct inode *parent)
{
        struct lustre_nfs_fid *nfs_fid = (void *)fh;

        CDEBUG(D_INFO, "encoding for (%lu,"DFID") maxlen=%d minlen=%d\n",
              inode->i_ino, PFID(ll_inode2fid(inode)), *plen,
              (int)sizeof(struct lustre_nfs_fid));

        if (*plen < sizeof(struct lustre_nfs_fid) / 4)
                return 255;

        nfs_fid->lnf_child = *ll_inode2fid(inode);
        nfs_fid->lnf_parent = *ll_inode2fid(parent);
        *plen = sizeof(struct lustre_nfs_fid) / 4;

        return LUSTRE_NFS_FID;
}

static int ll_nfs_get_name_filldir(struct dir_context *ctx, const char *name,
                                   int namelen, loff_t hash, u64 ino,
                                   unsigned type)
{
        /* It is hack to access lde_fid for comparison with lgd_fid.
         * So the input 'name' must be part of the 'lu_dirent'. */
        struct lu_dirent *lde = container_of0(name, struct lu_dirent, lde_name);
        struct ll_getname_data *lgd =
                container_of(ctx, struct ll_getname_data, ctx);
        struct lu_fid fid;

        fid_le_to_cpu(&fid, &lde->lde_fid);
        if (lu_fid_eq(&fid, &lgd->lgd_fid)) {
                memcpy(lgd->lgd_name, name, namelen);
                lgd->lgd_name[namelen] = 0;
                lgd->lgd_found = 1;
        }
        return lgd->lgd_found;
}

static int ll_get_name(struct dentry *dentry, char *name,
                       struct dentry *child)
{
        struct inode *dir = dentry->d_inode;
        int rc;
        struct ll_getname_data lgd = {
                .lgd_name = name,
                .lgd_fid = ll_i2info(child->d_inode)->lli_fid,
                .ctx.actor = ll_nfs_get_name_filldir,
        };

        if (!dir || !S_ISDIR(dir->i_mode)) {
                rc = -ENOTDIR;
                goto out;
        }

        if (!dir->i_fop) {
                rc = -EINVAL;
                goto out;
        }

        mutex_lock(&dir->i_mutex);
        rc = ll_dir_read(dir, &lgd.ctx);
        mutex_unlock(&dir->i_mutex);
        if (!rc && !lgd.lgd_found)
                rc = -ENOENT;
out:
        return rc;
}

static struct dentry *ll_fh_to_dentry(struct super_block *sb, struct fid *fid,
                                      int fh_len, int fh_type)
{
        struct lustre_nfs_fid *nfs_fid = (struct lustre_nfs_fid *)fid;

        if (fh_type != LUSTRE_NFS_FID)
                return ERR_PTR(-EPROTO);

        return ll_iget_for_nfs(sb, &nfs_fid->lnf_child, &nfs_fid->lnf_parent);
}

static struct dentry *ll_fh_to_parent(struct super_block *sb, struct fid *fid,
                                      int fh_len, int fh_type)
{
        struct lustre_nfs_fid *nfs_fid = (struct lustre_nfs_fid *)fid;

        if (fh_type != LUSTRE_NFS_FID)
                return ERR_PTR(-EPROTO);

        return ll_iget_for_nfs(sb, &nfs_fid->lnf_parent, NULL);
}

static struct dentry *ll_get_parent(struct dentry *dchild)
{
        struct ptlrpc_request *req = NULL;
        struct inode      *dir = dchild->d_inode;
        struct ll_sb_info     *sbi;
        struct dentry    *result = NULL;
        struct mdt_body       *body;
        static char        dotdot[] = "..";
        struct md_op_data     *op_data;
        int                rc;
        int                   lmmsize;

        LASSERT(dir && S_ISDIR(dir->i_mode));

        sbi = ll_s2sbi(dir->i_sb);

        CDEBUG(D_INFO, "getting parent for (%lu,"DFID")\n",
                        dir->i_ino, PFID(ll_inode2fid(dir)));

        rc = ll_get_default_mdsize(sbi, &lmmsize);
        if (rc != 0)
                return ERR_PTR(rc);

        op_data = ll_prep_md_op_data(NULL, dir, NULL, dotdot,
                                     strlen(dotdot), lmmsize,
                                     LUSTRE_OPC_ANY, NULL);
        if (IS_ERR(op_data))
                return (void *)op_data;

        rc = md_getattr_name(sbi->ll_md_exp, op_data, &req);
        ll_finish_md_op_data(op_data);
        if (rc) {
                CERROR("failure %d inode %lu get parent\n", rc, dir->i_ino);
                return ERR_PTR(rc);
        }
        body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
        LASSERT(body->valid & OBD_MD_FLID);

        CDEBUG(D_INFO, "parent for "DFID" is "DFID"\n",
                PFID(ll_inode2fid(dir)), PFID(&body->fid1));

        result = ll_iget_for_nfs(dir->i_sb, &body->fid1, NULL);

        ptlrpc_req_finished(req);
        return result;
}

struct export_operations lustre_export_operations = {
       .get_parent = ll_get_parent,
       .encode_fh  = ll_encode_fh,
       .get_name   = ll_get_name,
        .fh_to_dentry = ll_fh_to_dentry,
        .fh_to_parent = ll_fh_to_parent,
};