/*
   * 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 - 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 = 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 = 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 (op->olt_magic != VXFS_OLT_MAGIC) {
  		printk(KERN_NOTICE "vxfs: ivalid olt magic number
  ");
  		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.
  ");
  		printk(KERN_NOTICE "vxfs: please notify hch@infradead.org
  ");
  		goto fail;
  	}
  
  	oaddr = bp->b_data + 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 (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 += ocp->olt_size;
  	}
  
  	brelse(bp);
  	return 0;
  
  fail:
  	brelse(bp);
  	return -EINVAL;
  }