fs/freevxfs/vxfs_bmap.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 - filesystem to disk block mapping.
  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_inode.h"
  39 #include "vxfs_extern.h"
  40
  41
  42 #ifdef DIAGNOSTIC
  43 static void
  44 vxfs_typdump(struct vxfs_typed *typ)
  45 {
  46         printk(KERN_DEBUG "type=%Lu ", typ->vt_hdr >> VXFS_TYPED_TYPESHIFT);
  47         printk("offset=%Lx ", typ->vt_hdr & VXFS_TYPED_OFFSETMASK);
  48         printk("block=%x ", typ->vt_block);
  49         printk("size=%x\n", typ->vt_size);
  50 }
  51 #endif
  52
  53 /**
  54  * vxfs_bmap_ext4 - do bmap for ext4 extents
  55  * @ip:         pointer to the inode we do bmap for
  56  * @iblock:     logical block.
  57  *
  58  * Description:
  59  *   vxfs_bmap_ext4 performs the bmap operation for inodes with
  60  *   ext4-style extents (which are much like the traditional UNIX
  61  *   inode organisation).
  62  *
  63  * Returns:
  64  *   The physical block number on success, else Zero.
  65  */
  66 static daddr_t
  67 vxfs_bmap_ext4(struct inode *ip, long bn)
  68 {
  69         struct super_block *sb = ip->i_sb;
  70         struct vxfs_inode_info *vip = VXFS_INO(ip);
  71         unsigned long bsize = sb->s_blocksize;
  72         u32 indsize = vip->vii_ext4.ve4_indsize;
  73         int i;
  74
  75         if (indsize > sb->s_blocksize)
  76                 goto fail_size;
  77
  78         for (i = 0; i < VXFS_NDADDR; i++) {
  79                 struct direct *d = vip->vii_ext4.ve4_direct + i;
  80                 if (bn >= 0 && bn < d->size)
  81                         return (bn + d->extent);
  82                 bn -= d->size;
  83         }
  84
  85         if ((bn / (indsize * indsize * bsize / 4)) == 0) {
  86                 struct buffer_head *buf;
  87                 daddr_t bno;
  88                 u32 *indir;
  89
  90                 buf = sb_bread(sb, vip->vii_ext4.ve4_indir[0]);
  91                 if (!buf || !buffer_mapped(buf))
  92                         goto fail_buf;
  93
  94                 indir = (u32 *)buf->b_data;
  95                 bno = indir[(bn/indsize) % (indsize*bn)] + (bn%indsize);
  96
  97                 brelse(buf);
  98                 return bno;
  99         } else
 100                 printk(KERN_WARNING "no matching indir?");
 101
 102         return 0;
 103
 104 fail_size:
 105         printk("vxfs: indirect extent too big!\n");
 106 fail_buf:
 107         return 0;
 108 }
 109
 110 /**
 111  * vxfs_bmap_indir - recursion for vxfs_bmap_typed
 112  * @ip:         pointer to the inode we do bmap for
 113  * @indir:      indirect block we start reading at
 114  * @size:       size of the typed area to search
 115  * @block:      partially result from further searches
 116  *
 117  * Description:
 118  *   vxfs_bmap_indir reads a &struct vxfs_typed at @indir
 119  *   and performs the type-defined action.
 120  *
 121  * Return Value:
 122  *   The physical block number on success, else Zero.
 123  *
 124  * Note:
 125  *   Kernelstack is rare.  Unrecurse?
 126  */
 127 static daddr_t
 128 vxfs_bmap_indir(struct inode *ip, long indir, int size, long block)
 129 {
 130         struct buffer_head              *bp = NULL;
 131         daddr_t                         pblock = 0;
 132         int                             i;
 133
 134         for (i = 0; i < size * VXFS_TYPED_PER_BLOCK(ip->i_sb); i++) {
 135                 struct vxfs_typed       *typ;
 136                 int64_t                 off;
 137
 138                 bp = sb_bread(ip->i_sb,
 139                                 indir + (i / VXFS_TYPED_PER_BLOCK(ip->i_sb)));
 140                 if (!bp || !buffer_mapped(bp))
 141                         return 0;
 142
 143                 typ = ((struct vxfs_typed *)bp->b_data) +
 144                         (i % VXFS_TYPED_PER_BLOCK(ip->i_sb));
 145                 off = (typ->vt_hdr & VXFS_TYPED_OFFSETMASK);
 146
 147                 if (block < off) {
 148                         brelse(bp);
 149                         continue;
 150                 }
 151
 152                 switch ((u_int32_t)(typ->vt_hdr >> VXFS_TYPED_TYPESHIFT)) {
 153                 case VXFS_TYPED_INDIRECT:
 154                         pblock = vxfs_bmap_indir(ip, typ->vt_block,
 155                                         typ->vt_size, block - off);
 156                         if (pblock == -2)
 157                                 break;
 158                         goto out;
 159                 case VXFS_TYPED_DATA:
 160                         if ((block - off) >= typ->vt_size)
 161                                 break;
 162                         pblock = (typ->vt_block + block - off);
 163                         goto out;
 164                 case VXFS_TYPED_INDIRECT_DEV4:
 165                 case VXFS_TYPED_DATA_DEV4: {
 166                         struct vxfs_typed_dev4  *typ4 =
 167                                 (struct vxfs_typed_dev4 *)typ;
 168
 169                         printk(KERN_INFO "\n\nTYPED_DEV4 detected!\n");
 170                         printk(KERN_INFO "block: %Lu\tsize: %Ld\tdev: %d\n",
 171                                (unsigned long long) typ4->vd4_block,
 172                                (unsigned long long) typ4->vd4_size,
 173                                typ4->vd4_dev);
 174                         goto fail;
 175                 }
 176                 default:
 177                         BUG();
 178                 }
 179                 brelse(bp);
 180         }
 181
 182 fail:
 183         pblock = 0;
 184 out:
 185         brelse(bp);
 186         return (pblock);
 187 }
 188
 189 /**
 190  * vxfs_bmap_typed - bmap for typed extents
 191  * @ip:         pointer to the inode we do bmap for
 192  * @iblock:     logical block
 193  *
 194  * Description:
 195  *   Performs the bmap operation for typed extents.
 196  *
 197  * Return Value:
 198  *   The physical block number on success, else Zero.
 199  */
 200 static daddr_t
 201 vxfs_bmap_typed(struct inode *ip, long iblock)
 202 {
 203         struct vxfs_inode_info          *vip = VXFS_INO(ip);
 204         daddr_t                         pblock = 0;
 205         int                             i;
 206
 207         for (i = 0; i < VXFS_NTYPED; i++) {
 208                 struct vxfs_typed       *typ = vip->vii_org.typed + i;
 209                 int64_t                 off = (typ->vt_hdr & VXFS_TYPED_OFFSETMASK);
 210
 211 #ifdef DIAGNOSTIC
 212                 vxfs_typdump(typ);
 213 #endif
 214                 if (iblock < off)
 215                         continue;
 216                 switch ((u_int32_t)(typ->vt_hdr >> VXFS_TYPED_TYPESHIFT)) {
 217                 case VXFS_TYPED_INDIRECT:
 218                         pblock = vxfs_bmap_indir(ip, typ->vt_block,
 219                                         typ->vt_size, iblock - off);
 220                         if (pblock == -2)
 221                                 break;
 222                         return (pblock);
 223                 case VXFS_TYPED_DATA:
 224                         if ((iblock - off) < typ->vt_size)
 225                                 return (typ->vt_block + iblock - off);
 226                         break;
 227                 case VXFS_TYPED_INDIRECT_DEV4:
 228                 case VXFS_TYPED_DATA_DEV4: {
 229                         struct vxfs_typed_dev4  *typ4 =
 230                                 (struct vxfs_typed_dev4 *)typ;
 231
 232                         printk(KERN_INFO "\n\nTYPED_DEV4 detected!\n");
 233                         printk(KERN_INFO "block: %Lu\tsize: %Ld\tdev: %d\n",
 234                                (unsigned long long) typ4->vd4_block,
 235                                (unsigned long long) typ4->vd4_size,
 236                                typ4->vd4_dev);
 237                         return 0;
 238                 }
 239                 default:
 240                         BUG();
 241                 }
 242         }
 243
 244         return 0;
 245 }
 246
 247 /**
 248  * vxfs_bmap1 - vxfs-internal bmap operation
 249  * @ip:                 pointer to the inode we do bmap for
 250  * @iblock:             logical block
 251  *
 252  * Description:
 253  *   vxfs_bmap1 perfoms a logical to physical block mapping
 254  *   for vxfs-internal purposes.
 255  *
 256  * Return Value:
 257  *   The physical block number on success, else Zero.
 258  */
 259 daddr_t
 260 vxfs_bmap1(struct inode *ip, long iblock)
 261 {
 262         struct vxfs_inode_info          *vip = VXFS_INO(ip);
 263
 264         if (VXFS_ISEXT4(vip))
 265                 return vxfs_bmap_ext4(ip, iblock);
 266         if (VXFS_ISTYPED(vip))
 267                 return vxfs_bmap_typed(ip, iblock);
 268         if (VXFS_ISNONE(vip))
 269                 goto unsupp;
 270         if (VXFS_ISIMMED(vip))
 271                 goto unsupp;
 272
 273         printk(KERN_WARNING "vxfs: inode %ld has no valid orgtype (%x)\n",
 274                         ip->i_ino, vip->vii_orgtype);
 275         BUG();
 276
 277 unsupp:
 278         printk(KERN_WARNING "vxfs: inode %ld has an unsupported orgtype (%x)\n",
 279                         ip->i_ino, vip->vii_orgtype);
 280         return 0;
 281 }