/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 *  linux/mds/mds_null.c
 *
 *  Lustre Metadata Server (mds) journal abstraction routines
 *
 *  Copyright (C) 2002  Cluster File Systems, Inc.
 *  author: Andreas Dilger <adilger@clusterfs.com>
 *
 *  This code is issued under the GNU General Public License.
 *  See the file COPYING in this distribution
 *
 */

#define DEBUG_SUBSYSTEM S_MDS

#include <linux/fs.h>
#include <linux/ext2_fs.h>
#include <linux/lustre_mds.h>
#include <linux/module.h>

static void *mds_ext2_start(struct inode *inode, int nblocks)
{
        return (void *)1;
}

static int mds_ext2_stop(struct inode *inode, void *handle)
{
        return 0;
}

static int mds_ext2_setattr(struct dentry *dentry, void *handle,
                            struct iattr *iattr)
{
        struct inode *inode = dentry->d_inode;

        lock_kernel();

        /* a _really_ horrible hack to avoid removing the data stored
           in the block pointers; this data is the object id
           this will go into an extended attribute at some point.
        */
        if (iattr->ia_valid & ATTR_SIZE) {
                /* ATTR_SIZE would invoke truncate: clear it */
                iattr->ia_valid &= ~ATTR_SIZE;
                inode->i_size = iattr->ia_size;

                /* make sure _something_ gets set - so new inode
                   goes to disk (probably won't work over XFS */
                if (!iattr->ia_valid & ATTR_MODE) {
                        iattr->ia_valid |= ATTR_MODE;
                        iattr->ia_mode = inode->i_mode;
                }
        }

        if (inode->i_op->setattr)
                rc = inode->i_op->setattr(dentry, iattr);
        else
                rc = inode_setattr(inode, iattr);

        unlock_kernel();

        return rc;
}

/*
 * FIXME: nasty hack - store the object id in the first two
 *        direct block spots.  This should be done with EAs...
 */
static int mds_ext2_set_objid(struct inode *inode, void *handle, obd_id id)
{
        (__u64)(inode->u.ext2_i.i_data[0]) = cpu_to_le64(id);
        return 0;
}

static int mds_ext2_get_objid(struct inode *inode, obd_id *id)
{
        *id = le64_to_cpu(inode->u.ext2_i.i_data[0]);

        return 0;
}

static ssize_t mds_ext2_readpage(struct file *file, char *buf, size_t count,
                                 loff_t *offset)
{
        if (S_ISREG(file->f_dentry->d_inode->i_mode))
                return file->f_op->read(file, buf, count, offset);
        else
                return generic_file_read(file, buf, count, offset);
}

static struct mds_fs_operations mds_ext2_fs_ops;

static void mds_ext2_delete_inode(struct inode *inode)
{
        if (S_ISREG(inode->i_mode))
                mds_ext2_set_objid(inode, NULL, 0);

        mds_ext2_fs_ops.cl_delete_inode(inode);
}

static int mds_ext2_set_last_rcvd(struct mds_obd *mds, void *handle)
{
        /* Bail for ext2 - can't tell when it is on disk anyways, sync? */
        mds->mds_last_committed = mds->mds_last_rcvd;

        return 0;
}

static int mds_ext2_journal_data(struct file *filp)
{
        return 0;
}

static struct mds_fs_operations mds_ext2_fs_ops = {
        fs_owner:               THIS_MODULE,
        fs_start:               mds_ext2_start,
        fs_commit:              mds_ext2_stop,
        fs_setattr:             mds_ext2_setattr,
        fs_set_objid:           mds_ext2_set_objid,
        fs_get_objid:           mds_ext2_get_objid,
        fs_readpage:            mds_ext2_readpage,
        fs_delete_inode:        mds_ext2_delete_inode,
        cl_delete_inode:        clear_inode,
        fs_journal_data:        mds_ext2_journal_data,
        fs_set_last_rcvd:       mds_ext2_set_last_rcvd,
};

static int __init mds_ext2_init(void)
{
        return mds_register_fs_type(&mds_ext2_fs_ops, "ext2");
}

static void __exit mds_ext2_exit(void)
{
        mds_unregister_fs_type("ext2");
}

MODULE_AUTHOR("Cluster File Systems, Inc. <adilger@clusterfs.com>");
MODULE_DESCRIPTION("Lustre MDS ext2 Filesystem Helper v0.1");
MODULE_LICENSE("GPL");

module_init(mds_ext2_init);
module_exit(mds_ext2_exit);