1/* $OpenBSD: setup.c,v 1.33 2019/07/01 07:13:44 kevlo Exp $ */ 2/* $NetBSD: setup.c,v 1.1 1997/06/11 11:22:01 bouyer Exp $ */ 3 4/* 5 * Copyright (c) 1997 Manuel Bouyer. 6 * Copyright (c) 1980, 1986, 1993 7 * The Regents of the University of California. All rights reserved. 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. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#define DKTYPENAMES 35#include <sys/param.h> /* DEV_BSIZE roundup */ 36#include <sys/time.h> 37#include <ufs/ext2fs/ext2fs_dinode.h> 38#include <ufs/ext2fs/ext2fs.h> 39#include <sys/stat.h> 40#include <sys/ioctl.h> 41#include <sys/dkio.h> 42#include <sys/disklabel.h> 43 44#include <errno.h> 45#include <fcntl.h> 46#include <stdio.h> 47#include <stdlib.h> 48#include <unistd.h> 49#include <string.h> 50#include <ctype.h> 51#include <err.h> 52 53#include "fsck.h" 54#include "extern.h" 55#include "fsutil.h" 56 57#define POWEROF2(num) (((num) & ((num) - 1)) == 0) 58 59void badsb(int, char *); 60int calcsb(char *, int, struct m_ext2fs *, struct disklabel *); 61static struct disklabel *getdisklabel(char *, int); 62static int readsb(int); 63 64int 65setup(char *dev) 66{ 67 long cg, asked, i; 68 long bmapsize; 69 struct disklabel *lp; 70 off_t sizepb; 71 struct stat statb; 72 struct m_ext2fs proto; 73 int doskipclean; 74 u_int64_t maxfilesize; 75 76 havesb = 0; 77 fswritefd = -1; 78 doskipclean = skipclean; 79 if (stat(dev, &statb) == -1) { 80 printf("Can't stat %s: %s\n", dev, strerror(errno)); 81 return (0); 82 } 83 if (!S_ISCHR(statb.st_mode)) { 84 pfatal("%s is not a character device", dev); 85 if (reply("CONTINUE") == 0) 86 return (0); 87 } 88 if ((fsreadfd = open(dev, O_RDONLY)) == -1) { 89 printf("Can't open %s: %s\n", dev, strerror(errno)); 90 return (0); 91 } 92 if (preen == 0) 93 printf("** %s", dev); 94 if (nflag || (fswritefd = open(dev, O_WRONLY)) == -1) { 95 fswritefd = -1; 96 if (preen) 97 pfatal("NO WRITE ACCESS"); 98 printf(" (NO WRITE)"); 99 } 100 if (preen == 0) 101 printf("\n"); 102 fsmodified = 0; 103 lfdir = 0; 104 initbarea(&sblk); 105 initbarea(&asblk); 106 sblk.b_un.b_buf = malloc(SBSIZE); 107 asblk.b_un.b_buf = malloc(SBSIZE); 108 if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL) 109 errexit("cannot allocate space for superblock\n"); 110 if ((lp = getdisklabel(NULL, fsreadfd)) != NULL) 111 secsize = lp->d_secsize; 112 else 113 secsize = DEV_BSIZE; 114 115 if (!hotroot()) { 116#ifndef SMALL 117 if (pledge("stdio getpw", NULL) == -1) 118 err(1, "pledge"); 119#else 120 if (pledge("stdio", NULL) == -1) 121 err(1, "pledge"); 122#endif 123 } 124 125 /* 126 * Read in the superblock, looking for alternates if necessary 127 */ 128 if (readsb(1) == 0) { 129 if (bflag || preen || calcsb(dev, fsreadfd, &proto, lp) == 0) 130 return(0); 131 if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0) 132 return (0); 133 for (cg = 1; cg < proto.e2fs_ncg; cg++) { 134 bflag = fsbtodb(&proto, 135 cg * proto.e2fs.e2fs_bpg + proto.e2fs.e2fs_first_dblock); 136 if (readsb(0) != 0) 137 break; 138 } 139 if (cg >= proto.e2fs_ncg) { 140 printf("%s %s\n%s %s\n%s %s\n", 141 "SEARCH FOR ALTERNATE SUPER-BLOCK", 142 "FAILED. YOU MUST USE THE", 143 "-b OPTION TO FSCK_FFS TO SPECIFY THE", 144 "LOCATION OF AN ALTERNATE", 145 "SUPER-BLOCK TO SUPPLY NEEDED", 146 "INFORMATION; SEE fsck_ext2fs(8)."); 147 return(0); 148 } 149 doskipclean = 0; 150 pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag); 151 } 152 if (debug) 153 printf("state = %d\n", sblock.e2fs.e2fs_state); 154 if (sblock.e2fs.e2fs_state == E2FS_ISCLEAN) { 155 if (doskipclean) { 156 pwarn("%sile system is clean; not checking\n", 157 preen ? "f" : "** F"); 158 return (-1); 159 } 160 if (!preen) 161 pwarn("** File system is already clean\n"); 162 } 163 maxfsblock = sblock.e2fs.e2fs_bcount; 164 maxino = sblock.e2fs_ncg * sblock.e2fs.e2fs_ipg; 165 sizepb = sblock.e2fs_bsize; 166 maxfilesize = sblock.e2fs_bsize * NDADDR - 1; 167 for (i = 0; i < NIADDR; i++) { 168 sizepb *= NINDIR(&sblock); 169 maxfilesize += sizepb; 170 } 171 /* 172 * Check and potentially fix certain fields in the super block. 173 */ 174 if (/* (sblock.e2fs.e2fs_rbcount < 0) || */ 175 (sblock.e2fs.e2fs_rbcount > sblock.e2fs.e2fs_bcount)) { 176 pfatal("IMPOSSIBLE RESERVED BLOCK COUNT=%d IN SUPERBLOCK", 177 sblock.e2fs.e2fs_rbcount); 178 if (reply("SET TO DEFAULT") == 1) { 179 sblock.e2fs.e2fs_rbcount = sblock.e2fs.e2fs_bcount * 0.1; 180 sbdirty(); 181 dirty(&asblk); 182 } 183 } 184 if (sblock.e2fs.e2fs_bpg != sblock.e2fs.e2fs_fpg) { 185 pfatal("WRONG FPG=%d (BPG=%d) IN SUPERBLOCK", 186 sblock.e2fs.e2fs_fpg, sblock.e2fs.e2fs_bpg); 187 return 0; 188 } 189 if (asblk.b_dirty && !bflag) { 190 copyback_sb(&asblk); 191 flush(fswritefd, &asblk); 192 } 193 /* 194 * read in the summary info. 195 */ 196 197 sblock.e2fs_gd = calloc(sblock.e2fs_ngdb, sblock.e2fs_bsize); 198 if (sblock.e2fs_gd == NULL) 199 errexit("out of memory\n"); 200 asked = 0; 201 for (i=0; i < sblock.e2fs_ngdb; i++) { 202 if (bread(fsreadfd,(char *) 203 &sblock.e2fs_gd[i* sblock.e2fs_bsize / sizeof(struct ext2_gd)], 204 fsbtodb(&sblock, ((sblock.e2fs_bsize>1024)?0:1)+i+1), 205 sblock.e2fs_bsize) != 0 && !asked) { 206 pfatal("BAD SUMMARY INFORMATION"); 207 if (reply("CONTINUE") == 0) 208 errexit("%s\n", ""); 209 asked++; 210 } 211 } 212 /* 213 * allocate and initialize the necessary maps 214 */ 215 bmapsize = roundup(howmany(maxfsblock, NBBY), sizeof(int16_t)); 216 blockmap = calloc((unsigned)bmapsize, sizeof (char)); 217 if (blockmap == NULL) { 218 printf("cannot alloc %u bytes for blockmap\n", 219 (unsigned)bmapsize); 220 goto badsblabel; 221 } 222 statemap = calloc((unsigned)(maxino + 2), sizeof(char)); 223 if (statemap == NULL) { 224 printf("cannot alloc %u bytes for statemap\n", 225 (unsigned)(maxino + 1)); 226 goto badsblabel; 227 } 228 typemap = calloc((unsigned)(maxino + 1), sizeof(u_char)); 229 if (typemap == NULL) { 230 printf("cannot alloc %u bytes for typemap\n", 231 (unsigned)(maxino + 1)); 232 goto badsblabel; 233 } 234 lncntp = calloc((unsigned)(maxino + 1), sizeof(int16_t)); 235 if (lncntp == NULL) { 236 printf("cannot alloc %u bytes for lncntp\n", 237 (unsigned)((maxino + 1) * sizeof(int16_t))); 238 goto badsblabel; 239 } 240 for (numdirs = 0, cg = 0; cg < sblock.e2fs_ncg; cg++) { 241 numdirs += letoh16(sblock.e2fs_gd[cg].ext2bgd_ndirs); 242 } 243 inplast = 0; 244 listmax = numdirs + 10; 245 inpsort = calloc((unsigned)listmax, sizeof(struct inoinfo *)); 246 inphead = calloc((unsigned)numdirs, sizeof(struct inoinfo *)); 247 if (inpsort == NULL || inphead == NULL) { 248 printf("cannot alloc %u bytes for inphead\n", 249 (unsigned)(numdirs * sizeof(struct inoinfo *))); 250 goto badsblabel; 251 } 252 bufinit(); 253 return (1); 254 255badsblabel: 256 ckfini(0); 257 return (0); 258} 259 260/* 261 * Read in the super block and its summary info. 262 */ 263static int 264readsb(int listerr) 265{ 266 daddr32_t super = bflag ? bflag : SBOFF / DEV_BSIZE; 267 268 if (bread(fsreadfd, (char *)sblk.b_un.b_fs, super, (long)SBSIZE) != 0) 269 return (0); 270 sblk.b_bno = super; 271 sblk.b_size = SBSIZE; 272 273 /* Copy the superblock in memory */ 274 e2fs_sbload(sblk.b_un.b_fs, &sblock.e2fs); 275 276 /* 277 * run a few consistency checks of the super block 278 */ 279 if (sblock.e2fs.e2fs_magic != E2FS_MAGIC) { 280 badsb(listerr, "MAGIC NUMBER WRONG"); return (0); 281 } 282 if (sblock.e2fs.e2fs_log_bsize > 2) { 283 badsb(listerr, "BAD LOG_BSIZE"); return (0); 284 } 285 if (sblock.e2fs.e2fs_bpg == 0) { 286 badsb(listerr, "BAD BLOCKS PER GROUP"); return (0); 287 } 288 289 /* compute the dynamic fields of the in-memory sb */ 290 /* compute dynamic sb infos */ 291 sblock.e2fs_ncg = 292 howmany(sblock.e2fs.e2fs_bcount - sblock.e2fs.e2fs_first_dblock, 293 sblock.e2fs.e2fs_bpg); 294 /* XXX assume hw bsize = 512 */ 295 sblock.e2fs_fsbtodb = sblock.e2fs.e2fs_log_bsize + 1; 296 sblock.e2fs_bsize = 1024 << sblock.e2fs.e2fs_log_bsize; 297 sblock.e2fs_bshift = LOG_MINBSIZE + sblock.e2fs.e2fs_log_bsize; 298 sblock.e2fs_qbmask = sblock.e2fs_bsize - 1; 299 sblock.e2fs_bmask = ~sblock.e2fs_qbmask; 300 sblock.e2fs_ngdb = howmany(sblock.e2fs_ncg, 301 sblock.e2fs_bsize / sizeof(struct ext2_gd)); 302 sblock.e2fs_ipb = sblock.e2fs_bsize / EXT2_DINODE_SIZE(&sblock); 303 sblock.e2fs_itpg = sblock.e2fs.e2fs_ipg/sblock.e2fs_ipb; 304 305 /* 306 * Compute block size that the filesystem is based on, 307 * according to fsbtodb, and adjust superblock block number 308 * so we can tell if this is an alternate later. 309 */ 310 sblk.b_bno = super / DEV_BSIZE; 311 312 if (sblock.e2fs_ncg == 1) { 313 /* no alternate superblock; assume it's okey */ 314 havesb = 1; 315 return 1; 316 } 317 318 getblk(&asblk, 1 * sblock.e2fs.e2fs_bpg + sblock.e2fs.e2fs_first_dblock, 319 (long)SBSIZE); 320 if (asblk.b_errs) 321 return (0); 322 if (bflag) { 323 havesb = 1; 324 return (1); 325 } 326 327 /* 328 * Set all possible fields that could differ, then do check 329 * of whole super block against an alternate super block. 330 * When an alternate super-block is specified this check is skipped. 331 */ 332 asblk.b_un.b_fs->e2fs_rbcount = sblk.b_un.b_fs->e2fs_rbcount; 333 asblk.b_un.b_fs->e2fs_fbcount = sblk.b_un.b_fs->e2fs_fbcount; 334 asblk.b_un.b_fs->e2fs_ficount = sblk.b_un.b_fs->e2fs_ficount; 335 asblk.b_un.b_fs->e2fs_mtime = sblk.b_un.b_fs->e2fs_mtime; 336 asblk.b_un.b_fs->e2fs_wtime = sblk.b_un.b_fs->e2fs_wtime; 337 asblk.b_un.b_fs->e2fs_mnt_count = sblk.b_un.b_fs->e2fs_mnt_count; 338 asblk.b_un.b_fs->e2fs_max_mnt_count = sblk.b_un.b_fs->e2fs_max_mnt_count; 339 asblk.b_un.b_fs->e2fs_state = sblk.b_un.b_fs->e2fs_state; 340 asblk.b_un.b_fs->e2fs_beh = sblk.b_un.b_fs->e2fs_beh; 341 asblk.b_un.b_fs->e2fs_lastfsck = sblk.b_un.b_fs->e2fs_lastfsck; 342 asblk.b_un.b_fs->e2fs_fsckintv = sblk.b_un.b_fs->e2fs_fsckintv; 343 asblk.b_un.b_fs->e2fs_ruid = sblk.b_un.b_fs->e2fs_ruid; 344 asblk.b_un.b_fs->e2fs_rgid = sblk.b_un.b_fs->e2fs_rgid; 345 asblk.b_un.b_fs->e2fs_block_group_nr = 346 sblk.b_un.b_fs->e2fs_block_group_nr; 347 asblk.b_un.b_fs->e2fs_features_rocompat &= ~EXT2F_ROCOMPAT_LARGE_FILE; 348 asblk.b_un.b_fs->e2fs_features_rocompat |= 349 sblk.b_un.b_fs->e2fs_features_rocompat & EXT2F_ROCOMPAT_LARGE_FILE; 350 if (sblock.e2fs.e2fs_rev > E2FS_REV0 && 351 ((sblock.e2fs.e2fs_features_incompat & ~EXT2F_INCOMPAT_SUPP) || 352 (sblock.e2fs.e2fs_features_rocompat & ~EXT2F_ROCOMPAT_SUPP))) { 353 if (debug) { 354 printf("compat 0x%08x, incompat 0x%08x, compat_ro " 355 "0x%08x\n", 356 sblock.e2fs.e2fs_features_compat, 357 sblock.e2fs.e2fs_features_incompat, 358 sblock.e2fs.e2fs_features_rocompat); 359 } 360 badsb(listerr,"INCOMPATIBLE FEATURE BITS IN SUPER BLOCK"); 361 return 0; 362 } 363 if (memcmp(sblk.b_un.b_fs, asblk.b_un.b_fs, SBSIZE)) { 364 if (debug) { 365 u_int32_t *nlp, *olp, *endlp; 366 367 printf("superblock mismatches\n"); 368 nlp = (u_int32_t *)asblk.b_un.b_fs; 369 olp = (u_int32_t *)sblk.b_un.b_fs; 370 endlp = olp + (SBSIZE / sizeof *olp); 371 for ( ; olp < endlp; olp++, nlp++) { 372 if (*olp == *nlp) 373 continue; 374 printf("offset %ld, original %ld, alternate %ld\n", 375 (long)(olp - (u_int32_t *)sblk.b_un.b_fs), 376 (long)letoh32(*olp), 377 (long)letoh32(*nlp)); 378 } 379 } 380 badsb(listerr, 381 "VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE"); 382 return (0); 383 } 384 havesb = 1; 385 return (1); 386} 387 388void 389copyback_sb(struct bufarea *bp) 390{ 391 /* Copy the in-memory superblock back to buffer */ 392 bp->b_un.b_fs->e2fs_icount = letoh32(sblock.e2fs.e2fs_icount); 393 bp->b_un.b_fs->e2fs_bcount = letoh32(sblock.e2fs.e2fs_bcount); 394 bp->b_un.b_fs->e2fs_rbcount = letoh32(sblock.e2fs.e2fs_rbcount); 395 bp->b_un.b_fs->e2fs_fbcount = letoh32(sblock.e2fs.e2fs_fbcount); 396 bp->b_un.b_fs->e2fs_ficount = letoh32(sblock.e2fs.e2fs_ficount); 397 bp->b_un.b_fs->e2fs_first_dblock = 398 letoh32(sblock.e2fs.e2fs_first_dblock); 399 bp->b_un.b_fs->e2fs_log_bsize = letoh32(sblock.e2fs.e2fs_log_bsize); 400 bp->b_un.b_fs->e2fs_log_fsize = letoh32(sblock.e2fs.e2fs_log_fsize); 401 bp->b_un.b_fs->e2fs_bpg = letoh32(sblock.e2fs.e2fs_bpg); 402 bp->b_un.b_fs->e2fs_fpg = letoh32(sblock.e2fs.e2fs_fpg); 403 bp->b_un.b_fs->e2fs_ipg = letoh32(sblock.e2fs.e2fs_ipg); 404 bp->b_un.b_fs->e2fs_mtime = letoh32(sblock.e2fs.e2fs_mtime); 405 bp->b_un.b_fs->e2fs_wtime = letoh32(sblock.e2fs.e2fs_wtime); 406 bp->b_un.b_fs->e2fs_lastfsck = letoh32(sblock.e2fs.e2fs_lastfsck); 407 bp->b_un.b_fs->e2fs_fsckintv = letoh32(sblock.e2fs.e2fs_fsckintv); 408 bp->b_un.b_fs->e2fs_creator = letoh32(sblock.e2fs.e2fs_creator); 409 bp->b_un.b_fs->e2fs_rev = letoh32(sblock.e2fs.e2fs_rev); 410 bp->b_un.b_fs->e2fs_mnt_count = letoh16(sblock.e2fs.e2fs_mnt_count); 411 bp->b_un.b_fs->e2fs_max_mnt_count = 412 letoh16(sblock.e2fs.e2fs_max_mnt_count); 413 bp->b_un.b_fs->e2fs_magic = letoh16(sblock.e2fs.e2fs_magic); 414 bp->b_un.b_fs->e2fs_state = letoh16(sblock.e2fs.e2fs_state); 415 bp->b_un.b_fs->e2fs_beh = letoh16(sblock.e2fs.e2fs_beh); 416 bp->b_un.b_fs->e2fs_ruid = letoh16(sblock.e2fs.e2fs_ruid); 417 bp->b_un.b_fs->e2fs_rgid = letoh16(sblock.e2fs.e2fs_rgid); 418} 419 420void 421badsb(int listerr, char *s) 422{ 423 424 if (!listerr) 425 return; 426 if (preen) 427 printf("%s: ", cdevname()); 428 pfatal("BAD SUPER BLOCK: %s\n", s); 429} 430 431/* 432 * Calculate a prototype superblock based on information in the disk label. 433 * When done the cgsblock macro can be calculated and the fs_ncg field 434 * can be used. Do NOT attempt to use other macros without verifying that 435 * their needed information is available! 436 */ 437int 438calcsb(char *dev, int devfd, struct m_ext2fs *fs, struct disklabel *lp) 439{ 440 struct partition *pp; 441 char *cp; 442 443 cp = strchr(dev, '\0'); 444 if ((cp == NULL || (cp[-1] < 'a' || cp[-1] >= 'a' + MAXPARTITIONS)) && 445 !isdigit((unsigned char)cp[-1])) { 446 pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev); 447 return (0); 448 } 449 cp--; 450 if (lp == NULL) 451 pfatal("%s: CANNOT READ DISKLABEL\n", dev); 452 if (isdigit((unsigned char)*cp)) 453 pp = &lp->d_partitions[0]; 454 else 455 pp = &lp->d_partitions[*cp - 'a']; 456 if (pp->p_fstype != FS_EXT2FS) { 457 pfatal("%s: NOT LABELED AS A EXT2 FILE SYSTEM (%s)\n", 458 dev, pp->p_fstype < FSMAXTYPES ? 459 fstypenames[pp->p_fstype] : "unknown"); 460 return (0); 461 } 462 memset(fs, 0, sizeof(struct m_ext2fs)); 463 fs->e2fs_bsize = DISKLABELV1_FFS_FSIZE(pp->p_fragblock); /* XXX */ 464 if (fs->e2fs_bsize == 0) { 465 pfatal("%s: BLOCK SIZE DETERMINED TO BE ZERO\n", dev); 466 return (0); 467 } 468 fs->e2fs.e2fs_log_bsize = fs->e2fs_bsize / 1024; 469 fs->e2fs.e2fs_bcount = (pp->p_size * DEV_BSIZE) / fs->e2fs_bsize; 470 fs->e2fs.e2fs_first_dblock = (fs->e2fs.e2fs_log_bsize == 0) ? 1 : 0; 471 fs->e2fs.e2fs_bpg = fs->e2fs_bsize * NBBY; 472 fs->e2fs_bshift = LOG_MINBSIZE + fs->e2fs.e2fs_log_bsize; 473 fs->e2fs_qbmask = fs->e2fs_bsize - 1; 474 fs->e2fs_bmask = ~fs->e2fs_qbmask; 475 fs->e2fs_ncg = 476 howmany(fs->e2fs.e2fs_bcount - fs->e2fs.e2fs_first_dblock, 477 fs->e2fs.e2fs_bpg); 478 fs->e2fs_fsbtodb = fs->e2fs.e2fs_log_bsize + 1; 479 fs->e2fs_ngdb = howmany(fs->e2fs_ncg, 480 fs->e2fs_bsize / sizeof(struct ext2_gd)); 481 482 return (1); 483} 484 485static struct disklabel * 486getdisklabel(char *s, int fd) 487{ 488 static struct disklabel lab; 489 490 if (ioctl(fd, DIOCGDINFO, (char *)&lab) == -1) { 491 if (s == NULL) 492 return (NULL); 493 pwarn("ioctl (GCINFO): %s\n", strerror(errno)); 494 errexit("%s: can't read disk label\n", s); 495 } 496 return (&lab); 497} 498 499daddr32_t 500cgoverhead(int c) 501{ 502 int overh; 503 overh = 1 /* block bitmap */ + 504 1 /* inode bitmap */ + 505 sblock.e2fs_itpg; 506 if (sblock.e2fs.e2fs_rev > E2FS_REV0 && 507 sblock.e2fs.e2fs_features_rocompat & EXT2F_ROCOMPAT_SPARSE_SUPER) { 508 if (cg_has_sb(c) == 0) 509 return overh; 510 } 511 overh += 1 + sblock.e2fs_ngdb; 512 return overh; 513} 514