sbin/ffsinfo/ffsinfo.c

   1 /*
   2  * Copyright (c) 2000 Christoph Herrmann, Thomas-Henning von Kamptz
   3  * Copyright (c) 1980, 1989, 1993 The Regents of the University of California.
   4  * All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * Christoph Herrmann and Thomas-Henning von Kamptz, Munich and Frankfurt.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgment:
  19  *      This product includes software developed by the University of
  20  *      California, Berkeley and its contributors, as well as Christoph
  21  *      Herrmann and Thomas-Henning von Kamptz.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  * $TSHeader: src/sbin/ffsinfo/ffsinfo.c,v 1.4 2000/12/12 19:30:55 tomsoft Exp $
  39  * $FreeBSD: src/sbin/ffsinfo/ffsinfo.c,v 1.3.2.1 2001/07/16 15:01:56 tomsoft Exp $
  40  * $DragonFly: src/sbin/ffsinfo/ffsinfo.c,v 1.2 2003/06/17 04:27:32 dillon Exp $
  41  *
  42  * @(#) Copyright (c) 2000 Christoph Herrmann, Thomas-Henning von Kamptz Copyright (c) 1980, 1989, 1993 The Regents of the University of California. All rights reserved.
  43  * $FreeBSD: src/sbin/ffsinfo/ffsinfo.c,v 1.3.2.1 2001/07/16 15:01:56 tomsoft Exp $
  44  */
  45
  46 /* ********************************************************** INCLUDES ***** */
  47 #include <sys/param.h>
  48 #include <sys/disklabel.h>
  49 #include <sys/stat.h>
  50
  51 #include <stdio.h>
  52 #include <paths.h>
  53 #include <ctype.h>
  54 #include <err.h>
  55 #include <fcntl.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58 #include <unistd.h>
  59
  60 #include "debug.h"
  61
  62 /* *********************************************************** GLOBALS ***** */
  63 #ifdef FS_DEBUG
  64 int     _dbg_lvl_ = (DL_INFO); /* DL_TRC */
  65 #endif /* FS_DEBUG */
  66
  67 static union {
  68         struct fs       fs;
  69         char    pad[SBSIZE];
  70 } fsun1, fsun2;
  71 #define sblock  fsun1.fs
  72 #define osblock fsun2.fs
  73
  74 static union {
  75         struct cg       cg;
  76         char    pad[MAXBSIZE];
  77 } cgun1;
  78 #define acg     cgun1.cg
  79
  80 static char     ablk[MAXBSIZE];
  81 static char     i1blk[MAXBSIZE];
  82 static char     i2blk[MAXBSIZE];
  83 static char     i3blk[MAXBSIZE];
  84
  85 static struct csum      *fscs;
  86
  87 /* ******************************************************** PROTOTYPES ***** */
  88 static void     rdfs(daddr_t, size_t, void *, int);
  89 static void     usage(void);
  90 static struct disklabel *get_disklabel(int);
  91 static struct dinode    *ginode(ino_t, int);
  92 static void     dump_whole_inode(ino_t, int, int);
  93
  94 /* ************************************************************** rdfs ***** */
  95 /*
  96  * Here we read some block(s) from disk.
  97  */
  98 void
  99 rdfs(daddr_t bno, size_t size, void *bf, int fsi)
 100 {
 101         DBG_FUNC("rdfs")
 102         ssize_t n;
 103
 104         DBG_ENTER;
 105
 106         if (lseek(fsi, (off_t)bno * DEV_BSIZE, 0) < 0) {
 107                 err(33, "rdfs: seek error: %ld", (long)bno);
 108         }
 109         n = read(fsi, bf, size);
 110         if (n != (ssize_t)size) {
 111                 err(34, "rdfs: read error: %ld", (long)bno);
 112         }
 113
 114         DBG_LEAVE;
 115         return;
 116 }
 117
 118 /* ************************************************************** main ***** */
 119 /*
 120  * ffsinfo(8) is a tool to dump all metadata of a filesystem. It helps to find
 121  * errors is the filesystem much easier. You can run ffsinfo before and  after
 122  * an  fsck(8),  and compare the two ascii dumps easy with diff, and  you  see
 123  * directly where the problem is. You can control how much detail you want  to
 124  * see  with some command line arguments. You can also easy check  the  status
 125  * of  a filesystem, like is there is enough space for growing  a  filesystem,
 126  * or  how  many active snapshots do we have. It provides much  more  detailed
 127  * information  then dumpfs. Snapshots, as they are very new, are  not  really
 128  * supported.  They  are just mentioned currently, but it is  planned  to  run
 129  * also over active snapshots, to even get that output.
 130  */
 131 int
 132 main(int argc, char **argv)
 133 {
 134         DBG_FUNC("main")
 135         char    *device, *special, *cp;
 136         char    ch;
 137         size_t  len;
 138         struct stat     st;
 139         struct disklabel        *lp;
 140         struct partition        *pp;
 141         int     fsi;
 142         struct csum     *dbg_csp;
 143         int     dbg_csc;
 144         char    dbg_line[80];
 145         int     cylno,i;
 146         int     cfg_cg, cfg_in, cfg_lv;
 147         int     cg_start, cg_stop;
 148         ino_t   in;
 149         char    *out_file;
 150         int     Lflag=0;
 151
 152         DBG_ENTER;
 153
 154         cfg_lv=0xff;
 155         cfg_in=-2;
 156         cfg_cg=-2;
 157         out_file=strdup("/var/tmp/ffsinfo");
 158         if(out_file == NULL) {
 159                 errx(1, "strdup failed");
 160         }
 161
 162         while ((ch=getopt(argc, argv, "Lg:i:l:o:")) != -1) {
 163                 switch(ch) {
 164                 case 'L':
 165                         Lflag=1;
 166                         break;
 167                 case 'g':
 168                         cfg_cg=atol(optarg);
 169                         if(cfg_cg < -1) {
 170                                 usage();
 171                         }
 172                         break;
 173                 case 'i':
 174                         cfg_in=atol(optarg);
 175                         if(cfg_in < 0) {
 176                                 usage();
 177                         }
 178                         break;
 179                 case 'l':
 180                         cfg_lv=atol(optarg);
 181                         if(cfg_lv < 0x1||cfg_lv > 0x3ff) {
 182                                 usage();
 183                         }
 184                         break;
 185                 case 'o':
 186                         free(out_file);
 187                         out_file=strdup(optarg);
 188                         if(out_file == NULL) {
 189                                 errx(1, "strdup failed");
 190                         }
 191                         break;
 192                 case '?':
 193                         /* FALLTHROUGH */
 194                 default:
 195                         usage();
 196                 }
 197         }
 198         argc -= optind;
 199         argv += optind;
 200
 201         if(argc != 1) {
 202                 usage();
 203         }
 204         device=*argv;
 205
 206         /*
 207          * Now we try to guess the (raw)device name.
 208          */
 209         if (0 == strrchr(device, '/') && (stat(device, &st) == -1)) {
 210                 /*
 211                  * No path prefix was given, so try in that order:
 212                  *     /dev/r%s
 213                  *     /dev/%s
 214                  *     /dev/vinum/r%s
 215                  *     /dev/vinum/%s.
 216                  *
 217                  * FreeBSD now doesn't distinguish between raw and  block
 218                  * devices any longer, but it should still work this way.
 219                  */
 220                 len=strlen(device)+strlen(_PATH_DEV)+2+strlen("vinum/");
 221                 special=(char *)malloc(len);
 222                 if(special == NULL) {
 223                         errx(1, "malloc failed");
 224                 }
 225                 snprintf(special, len, "%sr%s", _PATH_DEV, device);
 226                 if (stat(special, &st) == -1) {
 227                         snprintf(special, len, "%s%s", _PATH_DEV, device);
 228                         if (stat(special, &st) == -1) {
 229                                 snprintf(special, len, "%svinum/r%s",
 230                                     _PATH_DEV, device);
 231                                 if (stat(special, &st) == -1) {
 232                                         /*
 233                                          * For now this is the 'last resort'.
 234                                          */
 235                                         snprintf(special, len, "%svinum/%s",
 236                                             _PATH_DEV, device);
 237                                 }
 238                         }
 239                 }
 240                 device = special;
 241         }
 242
 243         /*
 244          * Open our device for reading.
 245          */
 246         fsi = open(device, O_RDONLY);
 247         if (fsi < 0) {
 248                 err(1, "%s", device);
 249         }
 250
 251         stat(device, &st);
 252
 253         if(S_ISREG(st.st_mode)) { /* label check not supported for files */
 254                 Lflag=1;
 255         }
 256
 257         if(!Lflag) {
 258                 /*
 259                  * Try  to read a label and gess the slice if not  specified.
 260                  * This code should guess the right thing and avaid to bother
 261                  * the user user with the task of specifying the option -v on
 262                  * vinum volumes.
 263                  */
 264                 cp=device+strlen(device)-1;
 265                 lp = get_disklabel(fsi);
 266                 if(lp->d_type == DTYPE_VINUM) {
 267                         pp = &lp->d_partitions[0];
 268                 } else if (isdigit(*cp)) {
 269                         pp = &lp->d_partitions[2];
 270                 } else if (*cp>='a' && *cp<='h') {
 271                         pp = &lp->d_partitions[*cp - 'a'];
 272                 } else {
 273                         errx(1, "unknown device");
 274                 }
 275
 276                 /*
 277                  * Check if that partition looks suited for dumping.
 278                  */
 279                 if (pp->p_size < 1) {
 280                         errx(1, "partition is unavailable");
 281                 }
 282                 if (pp->p_fstype != FS_BSDFFS) {
 283                         errx(1, "partition not 4.2BSD");
 284                 }
 285         }
 286
 287         /*
 288          * Read the current superblock.
 289          */
 290         rdfs((daddr_t)(SBOFF/DEV_BSIZE), (size_t)SBSIZE, (void *)&sblock, fsi);
 291         if (sblock.fs_magic != FS_MAGIC) {
 292                 errx(1, "superblock not recognized");
 293         }
 294
 295         DBG_OPEN(out_file); /* already here we need a superblock */
 296
 297         if(cfg_lv & 0x001) {
 298                 DBG_DUMP_FS(&sblock,
 299                     "primary sblock");
 300         }
 301
 302         /*
 303          * Determine here what cylinder groups to dump.
 304          */
 305         if(cfg_cg==-2) {
 306                 cg_start=0;
 307                 cg_stop=sblock.fs_ncg;
 308         } else if (cfg_cg==-1) {
 309                 cg_start=sblock.fs_ncg-1;
 310                 cg_stop=sblock.fs_ncg;
 311         } else if (cfg_cg<sblock.fs_ncg) {
 312                 cg_start=cfg_cg;
 313                 cg_stop=cfg_cg+1;
 314         } else {
 315                 cg_start=sblock.fs_ncg;
 316                 cg_stop=sblock.fs_ncg;
 317         }
 318
 319         if (cfg_lv & 0x004) {
 320                 fscs = (struct csum *)calloc((size_t)1,
 321                     (size_t)sblock.fs_cssize);
 322                 if(fscs == NULL) {
 323                         errx(1, "calloc failed");
 324                 }
 325
 326                 /*
 327                  * Get the cylinder summary into the memory ...
 328                  */
 329                 for (i = 0; i < sblock.fs_cssize; i += sblock.fs_bsize) {
 330                         rdfs(fsbtodb(&sblock, sblock.fs_csaddr +
 331                             numfrags(&sblock, i)), (size_t)(sblock.fs_cssize-i<
 332                             sblock.fs_bsize ? sblock.fs_cssize - i :
 333                             sblock.fs_bsize), (void *)(((char *)fscs)+i), fsi);
 334                 }
 335
 336                 dbg_csp=fscs;
 337                 /*
 338                  * ... and dump it.
 339                  */
 340                 for(dbg_csc=0; dbg_csc<sblock.fs_ncg; dbg_csc++) {
 341                         snprintf(dbg_line, sizeof(dbg_line),
 342                             "%d. csum in fscs", dbg_csc);
 343                         DBG_DUMP_CSUM(&sblock,
 344                             dbg_line,
 345                             dbg_csp++);
 346                 }
 347         }
 348
 349         /*
 350          * For each requested cylinder group ...
 351          */
 352         for(cylno=cg_start; cylno<cg_stop; cylno++) {
 353                 snprintf(dbg_line, sizeof(dbg_line), "cgr %d", cylno);
 354                 if(cfg_lv & 0x002) {
 355                         /*
 356                          * ... dump the superblock copies ...
 357                          */
 358                         rdfs(fsbtodb(&sblock, cgsblock(&sblock, cylno)),
 359                             (size_t)SBSIZE, (void *)&osblock, fsi);
 360                         DBG_DUMP_FS(&osblock,
 361                             dbg_line);
 362                 }
 363                 /*
 364                  * ... read the cylinder group and dump whatever was requested.
 365                  */
 366                 rdfs(fsbtodb(&sblock, cgtod(&sblock, cylno)),
 367                     (size_t)sblock.fs_cgsize, (void *)&acg, fsi);
 368                 if(cfg_lv & 0x008) {
 369                         DBG_DUMP_CG(&sblock,
 370                             dbg_line,
 371                             &acg);
 372                 }
 373                 if(cfg_lv & 0x010) {
 374                         DBG_DUMP_INMAP(&sblock,
 375                             dbg_line,
 376                             &acg);
 377                 }
 378                 if(cfg_lv & 0x020) {
 379                         DBG_DUMP_FRMAP(&sblock,
 380                             dbg_line,
 381                             &acg);
 382                 }
 383                 if(cfg_lv & 0x040) {
 384                         DBG_DUMP_CLMAP(&sblock,
 385                             dbg_line,
 386                             &acg);
 387                         DBG_DUMP_CLSUM(&sblock,
 388                             dbg_line,
 389                             &acg);
 390                 }
 391                 if(cfg_lv & 0x080) {
 392                         DBG_DUMP_SPTBL(&sblock,
 393                             dbg_line,
 394                             &acg);
 395                 }
 396         }
 397         /*
 398          * Dump the requested inode(s).
 399          */
 400         if(cfg_in != -2) {
 401                 dump_whole_inode((ino_t)cfg_in, fsi, cfg_lv);
 402         } else {
 403                 for(in=cg_start*sblock.fs_ipg; in<(ino_t)cg_stop*sblock.fs_ipg;
 404                     in++) {
 405                         dump_whole_inode(in, fsi, cfg_lv);
 406                 }
 407         }
 408
 409         DBG_CLOSE;
 410
 411         close(fsi);
 412
 413         DBG_LEAVE;
 414         return 0;
 415 }
 416
 417 /* ************************************************** dump_whole_inode ***** */
 418 /*
 419  * Here we dump a list of all blocks allocated by this inode. We follow
 420  * all indirect blocks.
 421  */
 422 void
 423 dump_whole_inode(ino_t inode, int fsi, int level)
 424 {
 425         DBG_FUNC("dump_whole_inode")
 426         struct dinode   *ino;
 427         int     rb;
 428         unsigned int    ind2ctr, ind3ctr;
 429         ufs_daddr_t     *ind2ptr, *ind3ptr;
 430         char    comment[80];
 431
 432         DBG_ENTER;
 433
 434         /*
 435          * Read the inode from disk/cache.
 436          */
 437         ino=ginode(inode, fsi);
 438
 439         if(ino->di_nlink==0) {
 440                 DBG_LEAVE;
 441                 return; /* inode not in use */
 442         }
 443
 444         /*
 445          * Dump the main inode structure.
 446          */
 447         snprintf(comment, sizeof(comment), "Inode 0x%08x", inode);
 448         if (level & 0x100) {
 449                 DBG_DUMP_INO(&sblock,
 450                     comment,
 451                     ino);
 452         }
 453
 454         if (!(level & 0x200)) {
 455                 DBG_LEAVE;
 456                 return;
 457         }
 458
 459         /*
 460          * Ok, now prepare for dumping all direct and indirect pointers.
 461          */
 462         rb=howmany(ino->di_size, sblock.fs_bsize)-NDADDR;
 463         if(rb>0) {
 464                 /*
 465                  * Dump single indirect block.
 466                  */
 467                 rdfs(fsbtodb(&sblock, ino->di_ib[0]), (size_t)sblock.fs_bsize,
 468                     (void *)&i1blk, fsi);
 469                 snprintf(comment, sizeof(comment), "Inode 0x%08x: indirect 0",
 470                     inode);
 471                 DBG_DUMP_IBLK(&sblock,
 472                     comment,
 473                     i1blk,
 474                     (size_t)rb);
 475                 rb-=howmany(sblock.fs_bsize, sizeof(ufs_daddr_t));
 476         }
 477         if(rb>0) {
 478                 /*
 479                  * Dump double indirect blocks.
 480                  */
 481                 rdfs(fsbtodb(&sblock, ino->di_ib[1]), (size_t)sblock.fs_bsize,
 482                     (void *)&i2blk, fsi);
 483                 snprintf(comment, sizeof(comment), "Inode 0x%08x: indirect 1",
 484                     inode);
 485                 DBG_DUMP_IBLK(&sblock,
 486                     comment,
 487                     i2blk,
 488                     howmany(rb, howmany(sblock.fs_bsize, sizeof(ufs_daddr_t))));
 489                 for(ind2ctr=0; ((ind2ctr < howmany(sblock.fs_bsize,
 490                     sizeof(ufs_daddr_t)))&&(rb>0)); ind2ctr++) {
 491                         ind2ptr=&((ufs_daddr_t *)(void *)&i2blk)[ind2ctr];
 492
 493                         rdfs(fsbtodb(&sblock, *ind2ptr),
 494                             (size_t)sblock.fs_bsize, (void *)&i1blk, fsi);
 495                         snprintf(comment, sizeof(comment),
 496                             "Inode 0x%08x: indirect 1->%d", inode, ind2ctr);
 497                         DBG_DUMP_IBLK(&sblock,
 498                             comment,
 499                             i1blk,
 500                             (size_t)rb);
 501                         rb-=howmany(sblock.fs_bsize, sizeof(ufs_daddr_t));
 502                 }
 503         }
 504         if(rb>0) {
 505                 /*
 506                  * Dump triple indirect blocks.
 507                  */
 508                 rdfs(fsbtodb(&sblock, ino->di_ib[2]), (size_t)sblock.fs_bsize,
 509                     (void *)&i3blk, fsi);
 510                 snprintf(comment, sizeof(comment), "Inode 0x%08x: indirect 2",
 511                     inode);
 512 #define SQUARE(a) ((a)*(a))
 513                 DBG_DUMP_IBLK(&sblock,
 514                     comment,
 515                     i3blk,
 516                     howmany(rb,
 517                       SQUARE(howmany(sblock.fs_bsize, sizeof(ufs_daddr_t)))));
 518 #undef SQUARE
 519                 for(ind3ctr=0; ((ind3ctr < howmany(sblock.fs_bsize,
 520                     sizeof(ufs_daddr_t)))&&(rb>0)); ind3ctr ++) {
 521                         ind3ptr=&((ufs_daddr_t *)(void *)&i3blk)[ind3ctr];
 522
 523                         rdfs(fsbtodb(&sblock, *ind3ptr),
 524                             (size_t)sblock.fs_bsize, (void *)&i2blk, fsi);
 525                         snprintf(comment, sizeof(comment),
 526                             "Inode 0x%08x: indirect 2->%d", inode, ind3ctr);
 527                         DBG_DUMP_IBLK(&sblock,
 528                             comment,
 529                             i2blk,
 530                             howmany(rb,
 531                               howmany(sblock.fs_bsize, sizeof(ufs_daddr_t))));
 532                         for(ind2ctr=0; ((ind2ctr < howmany(sblock.fs_bsize,
 533                             sizeof(ufs_daddr_t)))&&(rb>0)); ind2ctr ++) {
 534                                 ind2ptr=&((ufs_daddr_t *)(void *)&i2blk)
 535                                     [ind2ctr];
 536                                 rdfs(fsbtodb(&sblock, *ind2ptr),
 537                                     (size_t)sblock.fs_bsize, (void *)&i1blk,
 538                                     fsi);
 539                                 snprintf(comment, sizeof(comment),
 540                                     "Inode 0x%08x: indirect 2->%d->%d", inode,
 541                                     ind3ctr, ind3ctr);
 542                                 DBG_DUMP_IBLK(&sblock,
 543                                     comment,
 544                                     i1blk,
 545                                     (size_t)rb);
 546                                 rb-=howmany(sblock.fs_bsize,
 547                                     sizeof(ufs_daddr_t));
 548                         }
 549                 }
 550         }
 551
 552         DBG_LEAVE;
 553         return;
 554 }
 555
 556 /* ***************************************************** get_disklabel ***** */
 557 /*
 558  * Read the disklabel from disk.
 559  */
 560 struct disklabel *
 561 get_disklabel(int fd)
 562 {
 563         DBG_FUNC("get_disklabel")
 564         static struct disklabel *lab;
 565
 566         DBG_ENTER;
 567
 568         lab=(struct disklabel *)malloc(sizeof(struct disklabel));
 569         if (!lab) {
 570                 errx(1, "malloc failed");
 571         }
 572         if (ioctl(fd, DIOCGDINFO, (char *)lab) < 0) {
 573                 errx(1, "DIOCGDINFO failed");
 574                 exit(-1);
 575         }
 576
 577         DBG_LEAVE;
 578         return (lab);
 579 }
 580
 581
 582 /* ************************************************************* usage ***** */
 583 /*
 584  * Dump a line of usage.
 585  */
 586 void
 587 usage(void)
 588 {
 589         DBG_FUNC("usage")
 590
 591         DBG_ENTER;
 592
 593         fprintf(stderr,
 594             "usage: ffsinfo [-L] [-g cylgrp] [-i inode] [-l level] "
 595             "[-o outfile]\n"
 596             "               special | file\n");
 597
 598         DBG_LEAVE;
 599         exit(1);
 600 }
 601
 602 /* ************************************************************ ginode ***** */
 603 /*
 604  * This function provides access to an individual inode. We find out in which
 605  * block  the  requested inode is located, read it from disk if  needed,  and
 606  * return  the pointer into that block. We maintain a cache of one  block  to
 607  * not  read the same block again and again if we iterate linearly  over  all
 608  * inodes.
 609  */
 610 struct dinode *
 611 ginode(ino_t inumber, int fsi)
 612 {
 613         DBG_FUNC("ginode")
 614         ufs_daddr_t     iblk;
 615         static ino_t    startinum=0;    /* first inode in cached block */
 616         struct dinode   *pi;
 617
 618         DBG_ENTER;
 619
 620         pi=(struct dinode *)(void *)ablk;
 621         if (startinum == 0 || inumber < startinum ||
 622             inumber >= startinum + INOPB(&sblock)) {
 623                 /*
 624                  * The block needed is not cached, so we have to read it from
 625                  * disk now.
 626                  */
 627                 iblk = ino_to_fsba(&sblock, inumber);
 628                 rdfs(fsbtodb(&sblock, iblk), (size_t)sblock.fs_bsize,
 629                     (void *)&ablk, fsi);
 630                 startinum = (inumber / INOPB(&sblock)) * INOPB(&sblock);
 631         }
 632
 633         DBG_LEAVE;
 634         return (&(pi[inumber % INOPB(&sblock)]));
 635 }
 636