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vxfs_olt.c
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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 
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 [email protected]\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 }
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