fs/freevxfs/vxfs_olt.c

   1 /*
   2  * Copyright (c) 2000-2001 Christoph Hellwig.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions, and the following disclaimer,
  10  *    without modification.
  11  * 2. The name of the author may not be used to endorse or promote products
  12  *    derived from this software without specific prior written permission.
  13  *
  14  * Alternatively, this software may be distributed under the terms of the
  15  * GNU General Public License ("GPL").
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  21  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * Veritas filesystem driver - object location table support.
  32  */
  33 #include <linux/fs.h>
  34 #include <linux/buffer_head.h>
  35 #include <linux/kernel.h>
  36
  37 #include "vxfs.h"
  38 #include "vxfs_olt.h"
  39 #include "vxfs_extern.h"
  40
  41
  42 static inline void
  43 vxfs_get_fshead(struct vxfs_oltfshead *fshp, struct vxfs_sb_info *infp)
  44 {
  45         if (infp->vsi_fshino)
  46                 BUG();
  47         infp->vsi_fshino = fshp->olt_fsino[0];
  48 }
  49
  50 static inline void
  51 vxfs_get_ilist(struct vxfs_oltilist *ilistp, struct vxfs_sb_info *infp)
  52 {
  53         if (infp->vsi_iext)
  54                 BUG();
  55         infp->vsi_iext = ilistp->olt_iext[0];
  56 }
  57
  58 static inline u_long
  59 vxfs_oblock(struct super_block *sbp, daddr_t block, u_long bsize)
  60 {
  61         if (sbp->s_blocksize % bsize)
  62                 BUG();
  63         return (block * (sbp->s_blocksize / bsize));
  64 }
  65
  66
  67 /**
  68  * vxfs_read_olt - read olt
  69  * @sbp:        superblock of the filesystem
  70  * @bsize:      blocksize of the filesystem
  71  *
  72  * Description:
  73  *   vxfs_read_olt reads the olt of the filesystem described by @sbp
  74  *   into main memory and does some basic setup.
  75  *
  76  * Returns:
  77  *   Zero on success, else a negative error code.
  78  */
  79 int
  80 vxfs_read_olt(struct super_block *sbp, u_long bsize)
  81 {
  82         struct vxfs_sb_info     *infp = VXFS_SBI(sbp);
  83         struct buffer_head      *bp;
  84         struct vxfs_olt         *op;
  85         char                    *oaddr, *eaddr;
  86
  87
  88         bp = sb_bread(sbp, vxfs_oblock(sbp, infp->vsi_oltext, bsize));
  89         if (!bp || !bp->b_data)
  90                 goto fail;
  91
  92         op = (struct vxfs_olt *)bp->b_data;
  93         if (op->olt_magic != VXFS_OLT_MAGIC) {
  94                 printk(KERN_NOTICE "vxfs: ivalid olt magic number\n");
  95                 goto fail;
  96         }
  97
  98         /*
  99          * It is in theory possible that vsi_oltsize is > 1.
 100          * I've not seen any such filesystem yet and I'm lazy..  --hch
 101          */
 102         if (infp->vsi_oltsize > 1) {
 103                 printk(KERN_NOTICE "vxfs: oltsize > 1 detected.\n");
 104                 printk(KERN_NOTICE "vxfs: please notify hch@infradead.org\n");
 105                 goto fail;
 106         }
 107
 108         oaddr = bp->b_data + op->olt_size;
 109         eaddr = bp->b_data + (infp->vsi_oltsize * sbp->s_blocksize);
 110
 111         while (oaddr < eaddr) {
 112                 struct vxfs_oltcommon   *ocp =
 113                         (struct vxfs_oltcommon *)oaddr;
 114
 115                 switch (ocp->olt_type) {
 116                 case VXFS_OLT_FSHEAD:
 117                         vxfs_get_fshead((struct vxfs_oltfshead *)oaddr, infp);
 118                         break;
 119                 case VXFS_OLT_ILIST:
 120                         vxfs_get_ilist((struct vxfs_oltilist *)oaddr, infp);
 121                         break;
 122                 }
 123
 124                 oaddr += ocp->olt_size;
 125         }
 126
 127         brelse(bp);
 128         return 0;
 129
 130 fail:
 131         brelse(bp);
 132         return -EINVAL;
 133 }