/*
 * 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 - filesystem to disk block mapping.
 */
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/kernel.h>

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


#ifdef DIAGNOSTIC
static void
vxfs_typdump(struct vxfs_typed *typ)
{
        printk(KERN_DEBUG "type=%Lu ", typ->vt_hdr >> VXFS_TYPED_TYPESHIFT);
        printk("offset=%Lx ", typ->vt_hdr & VXFS_TYPED_OFFSETMASK);
        printk("block=%x ", typ->vt_block);
        printk("size=%x\n", typ->vt_size);
}
#endif

/**
 * vxfs_bmap_ext4 - do bmap for ext4 extents
 * @ip:         pointer to the inode we do bmap for
 * @iblock:     logical block.
 *
 * Description:
 *   vxfs_bmap_ext4 performs the bmap operation for inodes with
 *   ext4-style extents (which are much like the traditional UNIX
 *   inode organisation).
 *
 * Returns:
 *   The physical block number on success, else Zero.
 */
static daddr_t
vxfs_bmap_ext4(struct inode *ip, long bn)
{
        struct super_block *sb = ip->i_sb;
        struct vxfs_inode_info *vip = VXFS_INO(ip);
        unsigned long bsize = sb->s_blocksize;
        u32 indsize = vip->vii_ext4.ve4_indsize;
        int i;

        if (indsize > sb->s_blocksize)
                goto fail_size;

        for (i = 0; i < VXFS_NDADDR; i++) {
                struct direct *d = vip->vii_ext4.ve4_direct + i;
                if (bn >= 0 && bn < d->size)
                        return (bn + d->extent);
                bn -= d->size;
        }

        if ((bn / (indsize * indsize * bsize / 4)) == 0) {
                struct buffer_head *buf;
                daddr_t bno;
                u32 *indir;

                buf = sb_bread(sb, vip->vii_ext4.ve4_indir[0]);
                if (!buf || !buffer_mapped(buf))
                        goto fail_buf;

                indir = (u32 *)buf->b_data;
                bno = indir[(bn/indsize) % (indsize*bn)] + (bn%indsize);

                brelse(buf);
                return bno;
        } else
                printk(KERN_WARNING "no matching indir?");

        return 0;

fail_size:
        printk("vxfs: indirect extent too big!\n");
fail_buf:
        return 0;
}

/**
 * vxfs_bmap_indir - recursion for vxfs_bmap_typed
 * @ip:         pointer to the inode we do bmap for
 * @indir:      indirect block we start reading at
 * @size:       size of the typed area to search
 * @block:      partially result from further searches
 *
 * Description:
 *   vxfs_bmap_indir reads a &struct vxfs_typed at @indir
 *   and performs the type-defined action.
 *
 * Return Value:
 *   The physical block number on success, else Zero.
 *
 * Note:
 *   Kernelstack is rare.  Unrecurse?
 */
static daddr_t
vxfs_bmap_indir(struct inode *ip, long indir, int size, long block)
{
        struct buffer_head              *bp = NULL;
        daddr_t                         pblock = 0;
        int                             i;

        for (i = 0; i < size * VXFS_TYPED_PER_BLOCK(ip->i_sb); i++) {
                struct vxfs_typed       *typ;
                int64_t                 off;

                bp = sb_bread(ip->i_sb,
                                indir + (i / VXFS_TYPED_PER_BLOCK(ip->i_sb)));
                if (!bp || !buffer_mapped(bp))
                        return 0;

                typ = ((struct vxfs_typed *)bp->b_data) +
                        (i % VXFS_TYPED_PER_BLOCK(ip->i_sb));
                off = (typ->vt_hdr & VXFS_TYPED_OFFSETMASK);

                if (block < off) {
                        brelse(bp);
                        continue;
                }

                switch ((u_int32_t)(typ->vt_hdr >> VXFS_TYPED_TYPESHIFT)) {
                case VXFS_TYPED_INDIRECT:
                        pblock = vxfs_bmap_indir(ip, typ->vt_block,
                                        typ->vt_size, block - off);
                        if (pblock == -2)
                                break;
                        goto out;
                case VXFS_TYPED_DATA:
                        if ((block - off) >= typ->vt_size)
                                break;
                        pblock = (typ->vt_block + block - off);
                        goto out;
                case VXFS_TYPED_INDIRECT_DEV4:
                case VXFS_TYPED_DATA_DEV4: {
                        struct vxfs_typed_dev4  *typ4 =
                                (struct vxfs_typed_dev4 *)typ;

                        printk(KERN_INFO "\n\nTYPED_DEV4 detected!\n");
                        printk(KERN_INFO "block: %Lu\tsize: %Ld\tdev: %d\n",
                               (unsigned long long) typ4->vd4_block,
                               (unsigned long long) typ4->vd4_size,
                               typ4->vd4_dev);
                        goto fail;
                }
                default:
                        BUG();
                }
                brelse(bp);
        }

fail:
        pblock = 0;
out:
        brelse(bp);
        return (pblock);
}

/**
 * vxfs_bmap_typed - bmap for typed extents
 * @ip:         pointer to the inode we do bmap for
 * @iblock:     logical block
 *
 * Description:
 *   Performs the bmap operation for typed extents.
 *
 * Return Value:
 *   The physical block number on success, else Zero.
 */
static daddr_t
vxfs_bmap_typed(struct inode *ip, long iblock)
{
        struct vxfs_inode_info          *vip = VXFS_INO(ip);
        daddr_t                         pblock = 0;
        int                             i;

        for (i = 0; i < VXFS_NTYPED; i++) {
                struct vxfs_typed       *typ = vip->vii_org.typed + i;
                int64_t                 off = (typ->vt_hdr & VXFS_TYPED_OFFSETMASK);

#ifdef DIAGNOSTIC
                vxfs_typdump(typ);
#endif
                if (iblock < off)
                        continue;
                switch ((u_int32_t)(typ->vt_hdr >> VXFS_TYPED_TYPESHIFT)) {
                case VXFS_TYPED_INDIRECT:
                        pblock = vxfs_bmap_indir(ip, typ->vt_block,
                                        typ->vt_size, iblock - off);
                        if (pblock == -2)
                                break;
                        return (pblock);
                case VXFS_TYPED_DATA:
                        if ((iblock - off) < typ->vt_size)
                                return (typ->vt_block + iblock - off);
                        break;
                case VXFS_TYPED_INDIRECT_DEV4:
                case VXFS_TYPED_DATA_DEV4: {
                        struct vxfs_typed_dev4  *typ4 =
                                (struct vxfs_typed_dev4 *)typ;

                        printk(KERN_INFO "\n\nTYPED_DEV4 detected!\n");
                        printk(KERN_INFO "block: %Lu\tsize: %Ld\tdev: %d\n",
                               (unsigned long long) typ4->vd4_block,
                               (unsigned long long) typ4->vd4_size,
                               typ4->vd4_dev);
                        return 0;
                }
                default:
                        BUG();
                }
        }

        return 0;
}

/**
 * vxfs_bmap1 - vxfs-internal bmap operation
 * @ip:                 pointer to the inode we do bmap for
 * @iblock:             logical block
 *
 * Description:
 *   vxfs_bmap1 perfoms a logical to physical block mapping
 *   for vxfs-internal purposes.
 *
 * Return Value:
 *   The physical block number on success, else Zero.
 */
daddr_t
vxfs_bmap1(struct inode *ip, long iblock)
{
        struct vxfs_inode_info          *vip = VXFS_INO(ip);

        if (VXFS_ISEXT4(vip))
                return vxfs_bmap_ext4(ip, iblock);
        if (VXFS_ISTYPED(vip))
                return vxfs_bmap_typed(ip, iblock);
        if (VXFS_ISNONE(vip))
                goto unsupp;
        if (VXFS_ISIMMED(vip))
                goto unsupp;

        printk(KERN_WARNING "vxfs: inode %ld has no valid orgtype (%x)\n",
                        ip->i_ino, vip->vii_orgtype);
        BUG();

unsupp:
        printk(KERN_WARNING "vxfs: inode %ld has an unsupported orgtype (%x)\n",
                        ip->i_ino, vip->vii_orgtype);
        return 0;
}