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