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/* -*- mode: c; c-basic-offset: 8; -*-

 * vim: noexpandtab sw=8 ts=8 sts=0:

 *

 * export.c

 *

 * Functions to facilitate NFS exporting

 *

 * Copyright (C) 2002, 2005 Oracle.  All rights reserved.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * 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 for more details.

 *

 * You should have received a copy of the GNU General Public

 * License along with this program; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 021110-1307, USA.

 */

#include <linux/fs.h>

#include <linux/types.h>

#define MLOG_MASK_PREFIX ML_EXPORT

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "dir.h"

#include "dlmglue.h"

#include "dcache.h"

#include "export.h"

#include "inode.h"

#include "buffer_head_io.h"

struct ocfs2_inode_handle

{

        u64 ih_blkno;

        u32 ih_generation;

};

static struct dentry *ocfs2_get_dentry(struct super_block *sb,

                struct ocfs2_inode_handle *handle)

{

        struct inode *inode;

        struct dentry *result;

        mlog_entry("(0x%p, 0x%p)\n", sb, handle);

        if (handle->ih_blkno == 0) {

                mlog_errno(-ESTALE);

                return ERR_PTR(-ESTALE);

        }

        inode = ocfs2_iget(OCFS2_SB(sb), handle->ih_blkno, 0);

        if (IS_ERR(inode))

                return (void *)inode;

        if (handle->ih_generation != inode->i_generation) {

                iput(inode);

                return ERR_PTR(-ESTALE);

        }

        result = d_alloc_anon(inode);

        if (!result) {

                iput(inode);

                mlog_errno(-ENOMEM);

                return ERR_PTR(-ENOMEM);

        }

        result->d_op = &ocfs2_dentry_ops;

        mlog_exit_ptr(result);

        return result;

}

static struct dentry *ocfs2_get_parent(struct dentry *child)

{

        int status;

        u64 blkno;

        struct dentry *parent;

        struct inode *inode;

        struct inode *dir = child->d_inode;

        mlog_entry("(0x%p, '%.*s')\n", child,

                   child->d_name.len, child->d_name.name);

        mlog(0, "find parent of directory %llu\n",

             (unsigned long long)OCFS2_I(dir)->ip_blkno);

        status = ocfs2_meta_lock(dir, NULL, 0);

        if (status < 0) {

                if (status != -ENOENT)

                        mlog_errno(status);

                parent = ERR_PTR(status);

                goto bail;

        }

        status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);

        if (status < 0) {

                parent = ERR_PTR(-ENOENT);

                goto bail_unlock;

        }

        inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0);

        if (IS_ERR(inode)) {

                mlog(ML_ERROR, "Unable to create inode %llu\n",

                     (unsigned long long)blkno);

                parent = ERR_PTR(-EACCES);

                goto bail_unlock;

        }

        parent = d_alloc_anon(inode);

        if (!parent) {

                iput(inode);

                parent = ERR_PTR(-ENOMEM);

        }

        parent->d_op = &ocfs2_dentry_ops;

bail_unlock:

        ocfs2_meta_unlock(dir, 0);

bail:

        mlog_exit_ptr(parent);

        return parent;

}

static int ocfs2_encode_fh(struct dentry *dentry, u32 *fh_in, int *max_len,

                           int connectable)

{

        struct inode *inode = dentry->d_inode;

        int len = *max_len;

        int type = 1;

        u64 blkno;

        u32 generation;

        __le32 *fh = (__force __le32 *) fh_in;

        mlog_entry("(0x%p, '%.*s', 0x%p, %d, %d)\n", dentry,

                   dentry->d_name.len, dentry->d_name.name,

                   fh, len, connectable);

        if (len < 3 || (connectable && len < 6)) {

                mlog(ML_ERROR, "fh buffer is too small for encoding\n");

                type = 255;

                goto bail;

        }

        blkno = OCFS2_I(inode)->ip_blkno;

        generation = inode->i_generation;

        mlog(0, "Encoding fh: blkno: %llu, generation: %u\n",

             (unsigned long long)blkno, generation);

        len = 3;

        fh[0] = cpu_to_le32((u32)(blkno >> 32));

        fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));

        fh[2] = cpu_to_le32(generation);

        if (connectable && !S_ISDIR(inode->i_mode)) {

                struct inode *parent;

                spin_lock(&dentry->d_lock);

                parent = dentry->d_parent->d_inode;

                blkno = OCFS2_I(parent)->ip_blkno;

                generation = parent->i_generation;

                fh[3] = cpu_to_le32((u32)(blkno >> 32));

                fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));

                fh[5] = cpu_to_le32(generation);

                spin_unlock(&dentry->d_lock);

                len = 6;

                type = 2;

                mlog(0, "Encoding parent: blkno: %llu, generation: %u\n",

                     (unsigned long long)blkno, generation);

        }

        *max_len = len;

bail:

        mlog_exit(type);

        return type;

}

static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,

                struct fid *fid, int fh_len, int fh_type)

{

        struct ocfs2_inode_handle handle;

        if (fh_len < 3 || fh_type > 2)

                return NULL;

        handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;

        handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);

        handle.ih_generation = le32_to_cpu(fid->raw[2]);

        return ocfs2_get_dentry(sb, &handle);

}

static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,

                struct fid *fid, int fh_len, int fh_type)

{

        struct ocfs2_inode_handle parent;

        if (fh_type != 2 || fh_len < 6)

                return NULL;

        parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;

        parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);

        parent.ih_generation = le32_to_cpu(fid->raw[5]);

        return ocfs2_get_dentry(sb, &parent);

}

const struct export_operations ocfs2_export_ops = {

        .encode_fh      = ocfs2_encode_fh,

        .fh_to_dentry   = ocfs2_fh_to_dentry,

        .fh_to_parent   = ocfs2_fh_to_parent,

        .get_parent     = ocfs2_get_parent,

};