// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2000-2001 Christoph Hellwig.
 */

/* 
 * Veritas filesystem driver - object location table support.
 */
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/kernel.h>

#include "vxfs.h"
#include "vxfs_olt.h"
#include "vxfs_extern.h"


static inline void
vxfs_get_fshead(struct vxfs_oltfshead *fshp, struct vxfs_sb_info *infp)
{
        BUG_ON(infp->vsi_fshino);
        infp->vsi_fshino = fs32_to_cpu(infp, fshp->olt_fsino[0]);
}

static inline void
vxfs_get_ilist(struct vxfs_oltilist *ilistp, struct vxfs_sb_info *infp)
{
        BUG_ON(infp->vsi_iext);
        infp->vsi_iext = fs32_to_cpu(infp, ilistp->olt_iext[0]);
}

static inline u_long
vxfs_oblock(struct super_block *sbp, daddr_t block, u_long bsize)
{
        BUG_ON(sbp->s_blocksize % bsize);
        return (block * (sbp->s_blocksize / bsize));
}


/**
 * vxfs_read_olt - read olt
 * @sbp:        superblock of the filesystem
 * @bsize:      blocksize of the filesystem
 *
 * Description:
 *   vxfs_read_olt reads the olt of the filesystem described by @sbp
 *   into main memory and does some basic setup.
 *
 * Returns:
 *   Zero on success, else a negative error code.
 */
int
vxfs_read_olt(struct super_block *sbp, u_long bsize)
{
        struct vxfs_sb_info     *infp = VXFS_SBI(sbp);
        struct buffer_head      *bp;
        struct vxfs_olt         *op;
        char                    *oaddr, *eaddr;

        bp = sb_bread(sbp, vxfs_oblock(sbp, infp->vsi_oltext, bsize));
        if (!bp || !bp->b_data)
                goto fail;

        op = (struct vxfs_olt *)bp->b_data;
        if (fs32_to_cpu(infp, op->olt_magic) != VXFS_OLT_MAGIC) {
                printk(KERN_NOTICE "vxfs: ivalid olt magic number\n");
                goto fail;
        }

        /*
         * It is in theory possible that vsi_oltsize is > 1.
         * I've not seen any such filesystem yet and I'm lazy..  --hch
         */
        if (infp->vsi_oltsize > 1) {
                printk(KERN_NOTICE "vxfs: oltsize > 1 detected.\n");
                printk(KERN_NOTICE "vxfs: please notify hch@infradead.org\n");
                goto fail;
        }

        oaddr = bp->b_data + fs32_to_cpu(infp, op->olt_size);
        eaddr = bp->b_data + (infp->vsi_oltsize * sbp->s_blocksize);

        while (oaddr < eaddr) {
                struct vxfs_oltcommon   *ocp =
                        (struct vxfs_oltcommon *)oaddr;
                
                switch (fs32_to_cpu(infp, ocp->olt_type)) {
                case VXFS_OLT_FSHEAD:
                        vxfs_get_fshead((struct vxfs_oltfshead *)oaddr, infp);
                        break;
                case VXFS_OLT_ILIST:
                        vxfs_get_ilist((struct vxfs_oltilist *)oaddr, infp);
                        break;
                }

                oaddr += fs32_to_cpu(infp, ocp->olt_size);
        }

        brelse(bp);
        return (infp->vsi_fshino && infp->vsi_iext) ? 0 : -EINVAL;

fail:
        brelse(bp);
        return -EINVAL;
}