sys/ufs/ext2fs/ext2fs_bmap.c

   1 /*      $NetBSD: ext2fs_bmap.c,v 1.24 2008/03/27 19:06:52 ad Exp $      */
   2
   3 /*
   4  * Copyright (c) 1989, 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  * (c) UNIX System Laboratories, Inc.
   7  * All or some portions of this file are derived from material licensed
   8  * to the University of California by American Telephone and Telegraph
   9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  10  * the permission of UNIX System Laboratories, Inc.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  *      @(#)ufs_bmap.c  8.6 (Berkeley) 1/21/94
  37  * Modified for ext2fs by Manuel Bouyer.
  38  */
  39
  40 /*
  41  * Copyright (c) 1997 Manuel Bouyer.
  42  *
  43  * Redistribution and use in source and binary forms, with or without
  44  * modification, are permitted provided that the following conditions
  45  * are met:
  46  * 1. Redistributions of source code must retain the above copyright
  47  *    notice, this list of conditions and the following disclaimer.
  48  * 2. Redistributions in binary form must reproduce the above copyright
  49  *    notice, this list of conditions and the following disclaimer in the
  50  *    documentation and/or other materials provided with the distribution.
  51  *
  52  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  53  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  54  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  55  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  56  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  57  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  58  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  59  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  60  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  61  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  62  *
  63  *      @(#)ufs_bmap.c  8.6 (Berkeley) 1/21/94
  64  * Modified for ext2fs by Manuel Bouyer.
  65  */
  66
  67 #include <sys/cdefs.h>
  68 __KERNEL_RCSID(0, "$NetBSD: ext2fs_bmap.c,v 1.24 2008/03/27 19:06:52 ad Exp $");
  69
  70 #include <sys/param.h>
  71 #include <sys/systm.h>
  72 #include <sys/buf.h>
  73 #include <sys/proc.h>
  74 #include <sys/vnode.h>
  75 #include <sys/mount.h>
  76 #include <sys/resourcevar.h>
  77 #include <sys/trace.h>
  78
  79 #include <miscfs/specfs/specdev.h>
  80
  81 #include <ufs/ufs/inode.h>
  82 #include <ufs/ufs/ufsmount.h>
  83 #include <ufs/ufs/ufs_extern.h>
  84 #include <ufs/ext2fs/ext2fs.h>
  85 #include <ufs/ext2fs/ext2fs_extern.h>
  86
  87 static int ext2fs_bmaparray(struct vnode *, daddr_t, daddr_t *,
  88                                 struct indir *, int *, int *);
  89
  90 #define is_sequential(ump, a, b)        ((b) == (a) + ump->um_seqinc)
  91
  92 /*
  93  * Bmap converts a the logical block number of a file to its physical block
  94  * number on the disk. The conversion is done by using the logical block
  95  * number to index into the array of block pointers described by the dinode.
  96  */
  97 int
  98 ext2fs_bmap(void *v)
  99 {
 100         struct vop_bmap_args /* {
 101                 struct vnode *a_vp;
 102                 daddr_t  a_bn;
 103                 struct vnode **a_vpp;
 104                 daddr_t *a_bnp;
 105                 int *a_runp;
 106         } */ *ap = v;
 107         /*
 108          * Check for underlying vnode requests and ensure that logical
 109          * to physical mapping is requested.
 110          */
 111         if (ap->a_vpp != NULL)
 112                 *ap->a_vpp = VTOI(ap->a_vp)->i_devvp;
 113         if (ap->a_bnp == NULL)
 114                 return (0);
 115
 116         return (ext2fs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL,
 117                 ap->a_runp));
 118 }
 119
 120 /*
 121  * Indirect blocks are now on the vnode for the file.  They are given negative
 122  * logical block numbers.  Indirect blocks are addressed by the negative
 123  * address of the first data block to which they point.  Double indirect blocks
 124  * are addressed by one less than the address of the first indirect block to
 125  * which they point.  Triple indirect blocks are addressed by one less than
 126  * the address of the first double indirect block to which they point.
 127  *
 128  * ext2fs_bmaparray does the bmap conversion, and if requested returns the
 129  * array of logical blocks which must be traversed to get to a block.
 130  * Each entry contains the offset into that block that gets you to the
 131  * next block and the disk address of the block (if it is assigned).
 132  */
 133
 134 int
 135 ext2fs_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, struct indir *ap,
 136                 int *nump, int *runp)
 137 {
 138         struct inode *ip;
 139         struct buf *bp, *cbp;
 140         struct ufsmount *ump;
 141         struct mount *mp;
 142         struct indir a[NIADDR+1], *xap;
 143         daddr_t daddr;
 144         daddr_t metalbn;
 145         int error, maxrun = 0, num;
 146
 147         ip = VTOI(vp);
 148         mp = vp->v_mount;
 149         ump = ip->i_ump;
 150 #ifdef DIAGNOSTIC
 151         if ((ap != NULL && nump == NULL) || (ap == NULL && nump != NULL))
 152                 panic("ext2fs_bmaparray: invalid arguments");
 153 #endif
 154
 155         if (runp) {
 156                 /*
 157                  * XXX
 158                  * If MAXBSIZE is the largest transfer the disks can handle,
 159                  * we probably want maxrun to be 1 block less so that we
 160                  * don't create a block larger than the device can handle.
 161                  */
 162                 *runp = 0;
 163                 maxrun = MAXBSIZE / mp->mnt_stat.f_iosize - 1;
 164         }
 165
 166         if (bn >= 0 && bn < NDADDR) {
 167                 /* XXX ondisk32 */
 168                 *bnp = blkptrtodb(ump, fs2h32(ip->i_e2fs_blocks[bn]));
 169                 if (*bnp == 0)
 170                         *bnp = -1;
 171                 else if (runp)
 172                         /* XXX ondisk32 */
 173                         for (++bn; bn < NDADDR && *runp < maxrun &&
 174                                 is_sequential(ump, (daddr_t)fs2h32(ip->i_e2fs_blocks[bn - 1]),
 175                                                           (daddr_t)fs2h32(ip->i_e2fs_blocks[bn]));
 176                                 ++bn, ++*runp);
 177                 return (0);
 178         }
 179
 180         xap = ap == NULL ? a : ap;
 181         if (!nump)
 182                 nump = &num;
 183         if ((error = ufs_getlbns(vp, bn, xap, nump)) != 0)
 184                 return (error);
 185
 186         num = *nump;
 187
 188         /* Get disk address out of indirect block array */
 189         /* XXX ondisk32 */
 190         daddr = fs2h32(ip->i_e2fs_blocks[NDADDR + xap->in_off]);
 191
 192 #ifdef DIAGNOSTIC
 193     if (num > NIADDR + 1 || num < 1) {
 194                 printf("ext2fs_bmaparray: num=%d\n", num);
 195                 panic("ext2fs_bmaparray: num");
 196         }
 197 #endif
 198         for (bp = NULL, ++xap; --num; ++xap) {
 199                 /*
 200                  * Exit the loop if there is no disk address assigned yet and
 201                  * the indirect block isn't in the cache, or if we were
 202                  * looking for an indirect block and we've found it.
 203                  */
 204
 205                 metalbn = xap->in_lbn;
 206                 if (metalbn == bn)
 207                         break;
 208                 if (daddr == 0) {
 209                         mutex_enter(&bufcache_lock);
 210                         cbp = incore(vp, metalbn);
 211                         mutex_exit(&bufcache_lock);
 212                         if (cbp == NULL)
 213                                 break;
 214                 }
 215                 /*
 216                  * If we get here, we've either got the block in the cache
 217                  * or we have a disk address for it, go fetch it.
 218                  */
 219                 if (bp)
 220                         brelse(bp, 0);
 221
 222                 xap->in_exists = 1;
 223                 bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0);
 224                 if (bp == NULL) {
 225
 226                         /*
 227                          * getblk() above returns NULL only iff we are
 228                          * pagedaemon.  See the implementation of getblk
 229                          * for detail.
 230                          */
 231
 232                          return (ENOMEM);
 233                 }
 234                 if (bp->b_oflags & (BO_DONE | BO_DELWRI)) {
 235                         trace(TR_BREADHIT, pack(vp, size), metalbn);
 236                 }
 237 #ifdef DIAGNOSTIC
 238                 else if (!daddr)
 239                         panic("ext2fs_bmaparry: indirect block not in cache");
 240 #endif
 241                 else {
 242                         trace(TR_BREADMISS, pack(vp, size), metalbn);
 243                         bp->b_blkno = blkptrtodb(ump, daddr);
 244                         bp->b_flags |= B_READ;
 245                         VOP_STRATEGY(vp, bp);
 246                         curlwp->l_ru.ru_inblock++;      /* XXX */
 247                         if ((error = biowait(bp)) != 0) {
 248                                 brelse(bp, 0);
 249                                 return (error);
 250                         }
 251                 }
 252
 253                 /* XXX ondisk32 */
 254                 daddr = fs2h32(((int32_t *)bp->b_data)[xap->in_off]);
 255                 if (num == 1 && daddr && runp)
 256                         /* XXX ondisk32 */
 257                         for (bn = xap->in_off + 1;
 258                                 bn < MNINDIR(ump) && *runp < maxrun &&
 259                                 is_sequential(ump, ((int32_t *)bp->b_data)[bn - 1],
 260                                 ((int32_t *)bp->b_data)[bn]);
 261                                 ++bn, ++*runp);
 262         }
 263         if (bp)
 264                 brelse(bp, 0);
 265
 266         daddr = blkptrtodb(ump, daddr);
 267         *bnp = daddr == 0 ? -1 : daddr;
 268         return (0);
 269 }