/*
 * Copyright (c) 2000-2001 Christoph Hellwig.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL").
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Veritas filesystem driver - superblock related routines.
 */
#include <linux/init.h>
#include <linux/module.h>

#include <linux/blkdev.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/vfs.h>
#include <linux/mount.h>

#include "vxfs.h"
#include "vxfs_extern.h"
#include "vxfs_dir.h"
#include "vxfs_inode.h"


MODULE_AUTHOR("Christoph Hellwig");
MODULE_DESCRIPTION("Veritas Filesystem (VxFS) driver");
MODULE_LICENSE("Dual BSD/GPL");

MODULE_ALIAS("vxfs"); /* makes mount -t vxfs autoload the module */


static void             vxfs_put_super(struct super_block *);
static int              vxfs_statfs(struct dentry *, struct kstatfs *);
static int              vxfs_remount(struct super_block *, int *, char *);

static const struct super_operations vxfs_super_ops = {
        .read_inode =           vxfs_read_inode,
        .clear_inode =          vxfs_clear_inode,
        .put_super =            vxfs_put_super,
        .statfs =               vxfs_statfs,
        .remount_fs =           vxfs_remount,
};

/**
 * vxfs_put_super - free superblock resources
 * @sbp:        VFS superblock.
 *
 * Description:
 *   vxfs_put_super frees all resources allocated for @sbp
 *   after the last instance of the filesystem is unmounted.
 */

static void
vxfs_put_super(struct super_block *sbp)
{
        struct vxfs_sb_info     *infp = VXFS_SBI(sbp);

        vxfs_put_fake_inode(infp->vsi_fship);
        vxfs_put_fake_inode(infp->vsi_ilist);
        vxfs_put_fake_inode(infp->vsi_stilist);

        brelse(infp->vsi_bp);
        kfree(infp);
}

/**
 * vxfs_statfs - get filesystem information
 * @dentry:     VFS dentry to locate superblock
 * @bufp:       output buffer
 *
 * Description:
 *   vxfs_statfs fills the statfs buffer @bufp with information
 *   about the filesystem described by @dentry.
 *
 * Returns:
 *   Zero.
 *
 * Locking:
 *   No locks held.
 *
 * Notes:
 *   This is everything but complete...
 */
static int
vxfs_statfs(struct dentry *dentry, struct kstatfs *bufp)
{
        struct vxfs_sb_info             *infp = VXFS_SBI(dentry->d_sb);

        bufp->f_type = VXFS_SUPER_MAGIC;
        bufp->f_bsize = dentry->d_sb->s_blocksize;
        bufp->f_blocks = infp->vsi_raw->vs_dsize;
        bufp->f_bfree = infp->vsi_raw->vs_free;
        bufp->f_bavail = 0;
        bufp->f_files = 0;
        bufp->f_ffree = infp->vsi_raw->vs_ifree;
        bufp->f_namelen = VXFS_NAMELEN;

        return 0;
}

static int vxfs_remount(struct super_block *sb, int *flags, char *data)
{
        *flags |= MS_RDONLY;
        return 0;
}

/**
 * vxfs_read_super - read superblock into memory and initalize filesystem
 * @sbp:                VFS superblock (to fill)
 * @dp:                 fs private mount data
 * @silent:             do not complain loudly when sth is wrong
 *
 * Description:
 *   We are called on the first mount of a filesystem to read the
 *   superblock into memory and do some basic setup.
 *
 * Returns:
 *   The superblock on success, else %NULL.
 *
 * Locking:
 *   We are under the bkl and @sbp->s_lock.
 */
static int vxfs_fill_super(struct super_block *sbp, void *dp, int silent)
{
        struct vxfs_sb_info     *infp;
        struct vxfs_sb          *rsbp;
        struct buffer_head      *bp = NULL;
        u_long                  bsize;
        struct inode *root;

        sbp->s_flags |= MS_RDONLY;

        infp = kzalloc(sizeof(*infp), GFP_KERNEL);
        if (!infp) {
                printk(KERN_WARNING "vxfs: unable to allocate incore superblock\n");
                return -ENOMEM;
        }

        bsize = sb_min_blocksize(sbp, BLOCK_SIZE);
        if (!bsize) {
                printk(KERN_WARNING "vxfs: unable to set blocksize\n");
                goto out;
        }

        bp = sb_bread(sbp, 1);
        if (!bp || !buffer_mapped(bp)) {
                if (!silent) {
                        printk(KERN_WARNING
                                "vxfs: unable to read disk superblock\n");
                }
                goto out;
        }

        rsbp = (struct vxfs_sb *)bp->b_data;
        if (rsbp->vs_magic != VXFS_SUPER_MAGIC) {
                if (!silent)
                        printk(KERN_NOTICE "vxfs: WRONG superblock magic\n");
                goto out;
        }

        if ((rsbp->vs_version < 2 || rsbp->vs_version > 4) && !silent) {
                printk(KERN_NOTICE "vxfs: unsupported VxFS version (%d)\n",
                       rsbp->vs_version);
                goto out;
        }

#ifdef DIAGNOSTIC
        printk(KERN_DEBUG "vxfs: supported VxFS version (%d)\n", rsbp->vs_version);
        printk(KERN_DEBUG "vxfs: blocksize: %d\n", rsbp->vs_bsize);
#endif

        sbp->s_magic = rsbp->vs_magic;
        sbp->s_fs_info = infp;

        infp->vsi_raw = rsbp;
        infp->vsi_bp = bp;
        infp->vsi_oltext = rsbp->vs_oltext[0];
        infp->vsi_oltsize = rsbp->vs_oltsize;

        if (!sb_set_blocksize(sbp, rsbp->vs_bsize)) {
                printk(KERN_WARNING "vxfs: unable to set final block size\n");
                goto out;
        }

        if (vxfs_read_olt(sbp, bsize)) {
                printk(KERN_WARNING "vxfs: unable to read olt\n");
                goto out;
        }

        if (vxfs_read_fshead(sbp)) {
                printk(KERN_WARNING "vxfs: unable to read fshead\n");
                goto out;
        }

        sbp->s_op = &vxfs_super_ops;
        root = iget(sbp, VXFS_ROOT_INO);
        sbp->s_root = d_alloc_root(root);
        if (!sbp->s_root) {
                iput(root);
                printk(KERN_WARNING "vxfs: unable to get root dentry.\n");
                goto out_free_ilist;
        }

        return 0;
        
out_free_ilist:
        vxfs_put_fake_inode(infp->vsi_fship);
        vxfs_put_fake_inode(infp->vsi_ilist);
        vxfs_put_fake_inode(infp->vsi_stilist);
out:
        brelse(bp);
        kfree(infp);
        return -EINVAL;
}

/*
 * The usual module blurb.
 */
static int vxfs_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
        return get_sb_bdev(fs_type, flags, dev_name, data, vxfs_fill_super,
                           mnt);
}

static struct file_system_type vxfs_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "vxfs",
        .get_sb         = vxfs_get_sb,
        .kill_sb        = kill_block_super,
        .fs_flags       = FS_REQUIRES_DEV,
};

static int __init
vxfs_init(void)
{
        int rv;

        vxfs_inode_cachep = kmem_cache_create("vxfs_inode",
                        sizeof(struct vxfs_inode_info), 0,
                        SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL);
        if (!vxfs_inode_cachep)
                return -ENOMEM;
        rv = register_filesystem(&vxfs_fs_type);
        if (rv < 0)
                kmem_cache_destroy(vxfs_inode_cachep);
        return rv;
}

static void __exit
vxfs_cleanup(void)
{
        unregister_filesystem(&vxfs_fs_type);
        kmem_cache_destroy(vxfs_inode_cachep);
}

module_init(vxfs_init);
module_exit(vxfs_cleanup);