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
  40
  41 static inline void
  42 vxfs_get_fshead(struct vxfs_oltfshead *fshp, struct vxfs_sb_info *infp)
  43 {
  44         if (infp->vsi_fshino)
  45                 BUG();
  46         infp->vsi_fshino = fshp->olt_fsino[0];
  47 }
  48
  49 static inline void
  50 vxfs_get_ilist(struct vxfs_oltilist *ilistp, struct vxfs_sb_info *infp)
  51 {
  52         if (infp->vsi_iext)
  53                 BUG();
  54         infp->vsi_iext = ilistp->olt_iext[0];
  55 }
  56
  57 static inline u_long
  58 vxfs_oblock(struct super_block *sbp, daddr_t block, u_long bsize)
  59 {
  60         if (sbp->s_blocksize % bsize)
  61                 BUG();
  62         return (block * (sbp->s_blocksize / bsize));
  63 }
  64
  65
  66 /**
  67  * vxfs_read_olt - read olt
  68  * @sbp:        superblock of the filesystem
  69  * @bsize:      blocksize of the filesystem
  70  *
  71  * Description:
  72  *   vxfs_read_olt reads the olt of the filesystem described by @sbp
  73  *   into main memory and does some basic setup.
  74  *
  75  * Returns:
  76  *   Zero on success, else a negative error code.
  77  */
  78 int
  79 vxfs_read_olt(struct super_block *sbp, u_long bsize)
  80 {
  81         struct vxfs_sb_info     *infp = VXFS_SBI(sbp);
  82         struct buffer_head      *bp;
  83         struct vxfs_olt         *op;
  84         char                    *oaddr, *eaddr;
  85
  86
  87         bp = sb_bread(sbp, vxfs_oblock(sbp, infp->vsi_oltext, bsize));
  88         if (!bp || !bp->b_data)
  89                 goto fail;
  90
  91         op = (struct vxfs_olt *)bp->b_data;
  92         if (op->olt_magic != VXFS_OLT_MAGIC) {
  93                 printk(KERN_NOTICE "vxfs: ivalid olt magic number\n");
  94                 goto fail;
  95         }
  96
  97         /*
  98          * It is in theory possible that vsi_oltsize is > 1.
  99          * I've not seen any such filesystem yet and I'm lazy..  --hch
 100          */
 101         if (infp->vsi_oltsize > 1) {
 102                 printk(KERN_NOTICE "vxfs: oltsize > 1 detected.\n");
 103                 printk(KERN_NOTICE "vxfs: please notify hch@infradead.org\n");
 104                 goto fail;
 105         }
 106
 107         oaddr = bp->b_data + op->olt_size;
 108         eaddr = bp->b_data + (infp->vsi_oltsize * sbp->s_blocksize);
 109
 110         while (oaddr < eaddr) {
 111                 struct vxfs_oltcommon   *ocp =
 112                         (struct vxfs_oltcommon *)oaddr;
 113
 114                 switch (ocp->olt_type) {
 115                 case VXFS_OLT_FSHEAD:
 116                         vxfs_get_fshead((struct vxfs_oltfshead *)oaddr, infp);
 117                         break;
 118                 case VXFS_OLT_ILIST:
 119                         vxfs_get_ilist((struct vxfs_oltilist *)oaddr, infp);
 120                         break;
 121                 }
 122
 123                 oaddr += ocp->olt_size;
 124         }
 125
 126         brelse(bp);
 127         return 0;
 128
 129 fail:
 130         brelse(bp);
 131         return -EINVAL;
 132 }