1 /* vi: set sw=4 ts=4: */
3 * mkfs_vfat: utility to create FAT32 filesystem
4 * inspired by dosfstools
6 * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
8 * Licensed under GPLv2, see file LICENSE in this source tree.
11 //usage:#define mkfs_vfat_trivial_usage
12 //usage: "[-v] [-n LABEL] BLOCKDEV [KBYTES]"
13 /* Accepted but ignored:
14 "[-c] [-C] [-I] [-l bad-block-file] [-b backup-boot-sector] "
15 "[-m boot-msg-file] [-i volume-id] "
16 "[-s sectors-per-cluster] [-S logical-sector-size] [-f number-of-FATs] "
17 "[-h hidden-sectors] [-F fat-size] [-r root-dir-entries] [-R reserved-sectors] "
19 //usage:#define mkfs_vfat_full_usage "\n\n"
20 //usage: "Make a FAT32 filesystem\n"
21 /* //usage: "\n -c Check device for bad blocks" */
22 //usage: "\n -v Verbose"
23 /* //usage: "\n -I Allow to use entire disk device (e.g. /dev/hda)" */
24 //usage: "\n -n LBL Volume label"
28 #include <linux/hdreg.h> /* HDIO_GETGEO */
29 #include <linux/fd.h> /* FDGETPRM */
30 #include <sys/mount.h> /* BLKSSZGET */
31 #if !defined(BLKSSZGET)
32 # define BLKSSZGET _IO(0x12, 104)
34 //#include <linux/msdos_fs.h>
36 #define SECTOR_SIZE 512
38 #define SECTORS_PER_BLOCK (BLOCK_SIZE / SECTOR_SIZE)
40 // M$ says the high 4 bits of a FAT32 FAT entry are reserved
41 #define EOF_FAT32 0x0FFFFFF8
42 #define BAD_FAT32 0x0FFFFFF7
43 #define MAX_CLUST_32 0x0FFFFFF0
49 /* FAT32 filesystem looks like this:
50 * sector -nn...-1: "hidden" sectors, all sectors before this partition
51 * (-h hidden-sectors sets it. Useful only for boot loaders,
52 * they need to know _disk_ offset in order to be able to correctly
53 * address sectors relative to start of disk)
54 * sector 0: boot sector
55 * sector 1: info sector
56 * sector 2: set aside for boot code which didn't fit into sector 0
57 * ...(zero-filled sectors)...
58 * sector B: backup copy of sector 0 [B set by -b backup-boot-sector]
59 * sector B+1: backup copy of sector 1
60 * sector B+2: backup copy of sector 2
61 * ...(zero-filled sectors)...
62 * sector R: FAT#1 [R set by -R reserved-sectors]
64 * sector R+fat_size: FAT#2
66 * sector R+fat_size*2: cluster #2
68 * sector R+fat_size*2+clust_size: cluster #3
69 * ...(the rest is filled by clusters till the end)...
73 // Perhaps this should remain constant
74 info_sector_number = 1,
75 // TODO: make these cmdline options
76 // dont forget sanity check: backup_boot_sector + 3 <= reserved_sect
77 backup_boot_sector = 3,
81 // how many blocks we try to read while testing
82 #define TEST_BUFFER_BLOCKS 16
84 struct msdos_dir_entry {
85 char name[11]; /* 000 name and extension */
86 uint8_t attr; /* 00b attribute bits */
87 uint8_t lcase; /* 00c case for base and extension */
88 uint8_t ctime_cs; /* 00d creation time, centiseconds (0-199) */
89 uint16_t ctime; /* 00e creation time */
90 uint16_t cdate; /* 010 creation date */
91 uint16_t adate; /* 012 last access date */
92 uint16_t starthi; /* 014 high 16 bits of cluster in FAT32 */
93 uint16_t time; /* 016 time */
94 uint16_t date; /* 018 date */
95 uint16_t start; /* 01a first cluster */
96 uint32_t size; /* 01c file size in bytes */
99 /* Example of boot sector's beginning:
100 0000 eb 58 90 4d 53 57 49 4e 34 2e 31 00 02 08 26 00 |...MSWIN4.1...&.|
101 0010 02 00 00 00 00 f8 00 00 3f 00 ff 00 3f 00 00 00 |........?...?...|
102 0020 54 9b d0 00 0d 34 00 00 00 00 00 00 02 00 00 00 |T....4..........|
103 0030 01 00 06 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
104 0040 80 00 29 71 df 51 e0 4e 4f 20 4e 41 4d 45 20 20 |..)q.Q.NO NAME |
105 0050 20 20 46 41 54 33 32 20 20 20 33 c9 8e d1 bc f4 | FAT32 3.....|
107 struct msdos_volume_info { /* (offsets are relative to start of boot sector) */
108 uint8_t drive_number; /* 040 BIOS drive number */
109 uint8_t reserved; /* 041 unused */
110 uint8_t ext_boot_sign; /* 042 0x29 if fields below exist (DOS 3.3+) */
111 uint32_t volume_id32; /* 043 volume ID number */
112 char volume_label[11];/* 047 volume label */
113 char fs_type[8]; /* 052 typically "FATnn" */
114 } PACKED; /* 05a end. Total size 26 (0x1a) bytes */
116 struct msdos_boot_sector {
117 /* We use strcpy to fill both, and gcc-4.4.x complains if they are separate */
118 char boot_jump_and_sys_id[3+8]; /* 000 short or near jump instruction */
119 /*char system_id[8];*/ /* 003 name - can be used to special case partition manager volumes */
120 uint16_t bytes_per_sect; /* 00b bytes per logical sector */
121 uint8_t sect_per_clust; /* 00d sectors/cluster */
122 uint16_t reserved_sect; /* 00e reserved sectors (sector offset of 1st FAT relative to volume start) */
123 uint8_t fats; /* 010 number of FATs */
124 uint16_t dir_entries; /* 011 root directory entries */
125 uint16_t volume_size_sect; /* 013 volume size in sectors */
126 uint8_t media_byte; /* 015 media code */
127 uint16_t sect_per_fat; /* 016 sectors/FAT */
128 uint16_t sect_per_track; /* 018 sectors per track */
129 uint16_t heads; /* 01a number of heads */
130 uint32_t hidden; /* 01c hidden sectors (sector offset of volume within physical disk) */
131 uint32_t fat32_volume_size_sect; /* 020 volume size in sectors (if volume_size_sect == 0) */
132 uint32_t fat32_sect_per_fat; /* 024 sectors/FAT */
133 uint16_t fat32_flags; /* 028 bit 8: fat mirroring, low 4: active fat */
134 uint8_t fat32_version[2]; /* 02a major, minor filesystem version (I see 0,0) */
135 uint32_t fat32_root_cluster; /* 02c first cluster in root directory */
136 uint16_t fat32_info_sector; /* 030 filesystem info sector (usually 1) */
137 uint16_t fat32_backup_boot; /* 032 backup boot sector (usually 6) */
138 uint32_t reserved2[3]; /* 034 unused */
139 struct msdos_volume_info vi; /* 040 */
140 char boot_code[0x200 - 0x5a - 2]; /* 05a */
141 #define BOOT_SIGN 0xAA55
142 uint16_t boot_sign; /* 1fe */
145 #define FAT_FSINFO_SIG1 0x41615252
146 #define FAT_FSINFO_SIG2 0x61417272
147 struct fat32_fsinfo {
148 uint32_t signature1; /* 0x52,0x52,0x41,0x61, "RRaA" */
149 uint32_t reserved1[128 - 8];
150 uint32_t signature2; /* 0x72,0x72,0x61,0x41, "rrAa" */
151 uint32_t free_clusters; /* free cluster count. -1 if unknown */
152 uint32_t next_cluster; /* most recently allocated cluster */
153 uint32_t reserved2[3];
154 uint16_t reserved3; /* 1fc */
155 uint16_t boot_sign; /* 1fe */
159 char BUG1[sizeof(struct msdos_dir_entry ) == 0x20 ? 1 : -1];
160 char BUG2[sizeof(struct msdos_volume_info) == 0x1a ? 1 : -1];
161 char BUG3[sizeof(struct msdos_boot_sector) == 0x200 ? 1 : -1];
162 char BUG4[sizeof(struct fat32_fsinfo ) == 0x200 ? 1 : -1];
165 static const char boot_code[] ALIGN1 =
166 "\x0e" /* 05a: push cs */
167 "\x1f" /* 05b: pop ds */
168 "\xbe\x77\x7c" /* write_msg: mov si, offset message_txt */
169 "\xac" /* 05f: lodsb */
170 "\x22\xc0" /* 060: and al, al */
171 "\x74\x0b" /* 062: jz key_press */
172 "\x56" /* 064: push si */
173 "\xb4\x0e" /* 065: mov ah, 0eh */
174 "\xbb\x07\x00" /* 067: mov bx, 0007h */
175 "\xcd\x10" /* 06a: int 10h */
176 "\x5e" /* 06c: pop si */
177 "\xeb\xf0" /* 06d: jmp write_msg */
178 "\x32\xe4" /* key_press: xor ah, ah */
179 "\xcd\x16" /* 071: int 16h */
180 "\xcd\x19" /* 073: int 19h */
181 "\xeb\xfe" /* foo: jmp foo */
182 /* 077: message_txt: */
183 "This is not a bootable disk\r\n";
186 #define MARK_CLUSTER(cluster, value) \
187 ((uint32_t *)fat)[cluster] = SWAP_LE32(value)
189 void BUG_unsupported_field_size(void);
190 #define STORE_LE(field, value) \
192 if (sizeof(field) == 4) \
193 field = SWAP_LE32(value); \
194 else if (sizeof(field) == 2) \
195 field = SWAP_LE16(value); \
196 else if (sizeof(field) == 1) \
199 BUG_unsupported_field_size(); \
203 * mkdosfs 2.11 (12 Mar 2005)
204 * Usage: mkdosfs [-A] [-c] [-C] [-v] [-I] [-l bad-block-file]
205 * [-b backup-boot-sector]
206 * [-m boot-msg-file] [-n volume-name] [-i volume-id]
207 * [-s sectors-per-cluster] [-S logical-sector-size]
208 * [-f number-of-FATs]
209 * [-h hidden-sectors] [-F fat-size] [-r root-dir-entries]
210 * [-R reserved-sectors]
213 int mkfs_vfat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
214 int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
217 const char *volume_label = "";
220 uoff_t volume_size_bytes;
221 uoff_t volume_size_sect;
222 uint32_t total_clust;
225 unsigned bytes_per_sect;
226 unsigned sect_per_fat;
228 uint16_t sect_per_track;
230 uint8_t sect_per_clust;
233 OPT_A = 1 << 0, // [IGNORED] atari format
234 OPT_b = 1 << 1, // [IGNORED] location of backup boot sector
235 OPT_c = 1 << 2, // [IGNORED] check filesystem
236 OPT_C = 1 << 3, // [IGNORED] create a new file
237 OPT_f = 1 << 4, // [IGNORED] number of FATs
238 OPT_F = 1 << 5, // [IGNORED, implied 32] choose FAT size
239 OPT_h = 1 << 6, // [IGNORED] number of hidden sectors
240 OPT_I = 1 << 7, // [IGNORED] don't bark at entire disk devices
241 OPT_i = 1 << 8, // [IGNORED] volume ID
242 OPT_l = 1 << 9, // [IGNORED] bad block filename
243 OPT_m = 1 << 10, // [IGNORED] message file
244 OPT_n = 1 << 11, // volume label
245 OPT_r = 1 << 12, // [IGNORED] root directory entries
246 OPT_R = 1 << 13, // [IGNORED] number of reserved sectors
247 OPT_s = 1 << 14, // [IGNORED] sectors per cluster
248 OPT_S = 1 << 15, // [IGNORED] sector size
249 OPT_v = 1 << 16, // verbose
252 opt_complementary = "-1";//:b+:f+:F+:h+:r+:R+:s+:S+:vv:c--l:l--c";
253 opts = getopt32(argv, "Ab:cCf:F:h:Ii:l:m:n:r:R:s:S:v",
254 NULL, NULL, NULL, NULL, NULL,
255 NULL, NULL, &volume_label, NULL, NULL, NULL, NULL);
259 device_name = argv[0];
260 // default volume ID = creation time
261 volume_id = time(NULL);
263 dev = xopen(device_name, O_RDWR);
264 xfstat(dev, &st, device_name);
267 // Get image size and sector size
269 bytes_per_sect = SECTOR_SIZE;
270 if (!S_ISBLK(st.st_mode)) {
271 if (!S_ISREG(st.st_mode)) {
273 bb_error_msg_and_die("image size must be specified");
275 // not a block device, skip bad sectors check
278 int min_bytes_per_sect;
281 // for true block devices we do check sanity
282 device_num = st.st_rdev & 0xff3f;
283 // do we allow to format the whole disk device?
284 if (!(opts & OPT_I) && (
285 device_num == 0x0300 || // hda, hdb
286 (device_num & 0xff0f) == 0x0800 || // sd
287 device_num == 0x0d00 || // xd
288 device_num == 0x1600 ) // hdc, hdd
290 bb_error_msg_and_die("will not try to make filesystem on full-disk device (use -I if wanted)");
291 // can't work on mounted filesystems
292 if (find_mount_point(device_name, 0))
293 bb_error_msg_and_die("can't format mounted filesystem");
295 // get true sector size
296 // (parameter must be int*, not long* or size_t*)
297 xioctl(dev, BLKSSZGET, &min_bytes_per_sect);
298 if (min_bytes_per_sect > SECTOR_SIZE) {
299 bytes_per_sect = min_bytes_per_sect;
300 bb_error_msg("for this device sector size is %u", min_bytes_per_sect);
303 volume_size_bytes = get_volume_size_in_bytes(dev, argv[1], 1024, /*extend:*/ 1);
304 volume_size_sect = volume_size_bytes / bytes_per_sect;
307 // Find out or guess media parameters
314 struct hd_geometry geometry;
315 // size (in sectors), sect (per track), head
316 struct floppy_struct param;
318 // N.B. whether to use HDIO_GETGEO or HDIO_REQ?
319 if (ioctl(dev, HDIO_GETGEO, &geometry) == 0
324 sect_per_track = geometry.sectors;
325 heads = geometry.heads;
328 /* For FAT32, try to do the same as M$'s format command
329 * (see http://www.win.tue.nl/~aeb/linux/fs/fat/fatgen103.pdf p. 20):
330 * fs size <= 260M: 0.5k clusters
331 * fs size <= 8G: 4k clusters
332 * fs size <= 16G: 8k clusters
333 * fs size > 16G: 16k clusters
336 if (volume_size_bytes >= 260*1024*1024) {
339 /* "error: integer overflow in expression" */
340 /* "error: right shift count >= width of type" */
341 if (sizeof(off_t) > 4) {
342 unsigned t = (volume_size_bytes >> 31 >> 1);
350 // floppy, loop, or regular file
351 int not_floppy = ioctl(dev, FDGETPRM, ¶m);
352 if (not_floppy == 0) {
354 sect_per_track = param.sect;
356 volume_size_sect = param.size;
357 volume_size_bytes = param.size * SECTOR_SIZE;
359 // setup the media descriptor byte
360 switch (volume_size_sect) {
361 case 2*360: // 5.25", 2, 9, 40 - 360K
364 case 2*720: // 3.5", 2, 9, 80 - 720K
365 case 2*1200: // 5.25", 2, 15, 80 - 1200K
368 default: // anything else
370 goto set_cluster_size;
371 case 2*1440: // 3.5", 2, 18, 80 - 1440K
372 case 2*2880: // 3.5", 2, 36, 80 - 2880K
376 // not floppy, but size matches floppy exactly.
377 // perhaps it is a floppy image.
378 // we already set media_byte as if it is a floppy,
379 // now set sect_per_track and heads.
381 sect_per_track = (unsigned)volume_size_sect / 160;
382 if (sect_per_track < 9)
388 // Calculate number of clusters, sectors/cluster, sectors/FAT
389 // (an initial guess for sect_per_clust should already be set)
391 // "mkdosfs -v -F 32 image5k 5" is the minimum:
392 // 2 sectors for FATs and 2 data sectors
393 if ((off_t)(volume_size_sect - reserved_sect) < 4)
394 bb_error_msg_and_die("the image is too small for FAT32");
399 uoff_t tcl = (volume_size_sect - reserved_sect - NUM_FATS * sect_per_fat) / sect_per_clust;
400 // tcl may be > MAX_CLUST_32 here, but it may be
401 // because sect_per_fat is underestimated,
402 // and with increased sect_per_fat it still may become
403 // <= MAX_CLUST_32. Therefore, we do not check
404 // against MAX_CLUST_32, but against a bigger const:
405 if (tcl > 0x80ffffff)
407 total_clust = tcl; // fits in uint32_t
408 // Every cluster needs 4 bytes in FAT. +2 entries since
409 // FAT has space for non-existent clusters 0 and 1.
410 // Let's see how many sectors that needs.
411 //May overflow at "*4":
412 //spf_adj = ((total_clust+2) * 4 + bytes_per_sect-1) / bytes_per_sect - sect_per_fat;
413 //Same in the more obscure, non-overflowing form:
414 spf_adj = ((total_clust+2) + (bytes_per_sect/4)-1) / (bytes_per_sect/4) - sect_per_fat;
416 bb_error_msg("sect_per_clust:%u sect_per_fat:%u total_clust:%u",
417 sect_per_clust, sect_per_fat, (int)tcl);
418 bb_error_msg("adjust to sect_per_fat:%d", spf_adj);
421 // do not need to adjust sect_per_fat.
422 // so, was total_clust too big after all?
423 if (total_clust <= MAX_CLUST_32)
424 goto found_total_clust; // no
425 // yes, total_clust is _a bit_ too big
428 // adjust sect_per_fat, go back and recalc total_clust
429 // (note: just "sect_per_fat += spf_adj" isn't ok)
430 sect_per_fat += ((unsigned)spf_adj / 2) | 1;
433 if (sect_per_clust == 128)
434 bb_error_msg_and_die("can't make FAT32 with >128 sectors/cluster");
436 sect_per_fat = (sect_per_fat / 2) | 1;
446 "heads:%u, sectors/track:%u, bytes/sector:%u\n"
447 "media descriptor:%02x\n"
448 "total sectors:%"OFF_FMT"u, clusters:%u, sectors/cluster:%u\n"
449 "FATs:2, sectors/FAT:%u\n"
450 "volumeID:%08x, label:'%s'\n",
452 heads, sect_per_track, bytes_per_sect,
454 volume_size_sect, (int)total_clust, (int)sect_per_clust,
456 (int)volume_id, volume_label
461 // Write filesystem image sequentially (no seeking)
464 // (a | b) is poor man's max(a, b)
465 unsigned bufsize = reserved_sect;
466 //bufsize |= sect_per_fat; // can be quite large
467 bufsize |= 2; // use this instead
468 bufsize |= sect_per_clust;
469 buf = xzalloc(bufsize * bytes_per_sect);
472 { // boot and fsinfo sectors, and their copies
473 struct msdos_boot_sector *boot_blk = (void*)buf;
474 struct fat32_fsinfo *info = (void*)(buf + bytes_per_sect);
476 strcpy(boot_blk->boot_jump_and_sys_id, "\xeb\x58\x90" "mkdosfs");
477 STORE_LE(boot_blk->bytes_per_sect, bytes_per_sect);
478 STORE_LE(boot_blk->sect_per_clust, sect_per_clust);
479 // cast in needed on big endian to suppress a warning
480 STORE_LE(boot_blk->reserved_sect, (uint16_t)reserved_sect);
481 STORE_LE(boot_blk->fats, 2);
482 //STORE_LE(boot_blk->dir_entries, 0); // for FAT32, stays 0
483 if (volume_size_sect <= 0xffff)
484 STORE_LE(boot_blk->volume_size_sect, volume_size_sect);
485 STORE_LE(boot_blk->media_byte, media_byte);
486 // wrong: this would make Linux think that it's fat12/16:
487 //if (sect_per_fat <= 0xffff)
488 // STORE_LE(boot_blk->sect_per_fat, sect_per_fat);
490 //STORE_LE(boot_blk->sect_per_fat, 0);
491 STORE_LE(boot_blk->sect_per_track, sect_per_track);
492 STORE_LE(boot_blk->heads, heads);
493 //STORE_LE(boot_blk->hidden, 0);
494 STORE_LE(boot_blk->fat32_volume_size_sect, volume_size_sect);
495 STORE_LE(boot_blk->fat32_sect_per_fat, sect_per_fat);
496 //STORE_LE(boot_blk->fat32_flags, 0);
497 //STORE_LE(boot_blk->fat32_version[2], 0,0);
498 STORE_LE(boot_blk->fat32_root_cluster, 2);
499 STORE_LE(boot_blk->fat32_info_sector, info_sector_number);
500 STORE_LE(boot_blk->fat32_backup_boot, backup_boot_sector);
501 //STORE_LE(boot_blk->reserved2[3], 0,0,0);
502 STORE_LE(boot_blk->vi.ext_boot_sign, 0x29);
503 STORE_LE(boot_blk->vi.volume_id32, volume_id);
504 strncpy(boot_blk->vi.fs_type, "FAT32 ", sizeof(boot_blk->vi.fs_type));
505 strncpy(boot_blk->vi.volume_label, volume_label, sizeof(boot_blk->vi.volume_label));
506 memcpy(boot_blk->boot_code, boot_code, sizeof(boot_code));
507 STORE_LE(boot_blk->boot_sign, BOOT_SIGN);
509 STORE_LE(info->signature1, FAT_FSINFO_SIG1);
510 STORE_LE(info->signature2, FAT_FSINFO_SIG2);
511 // we've allocated cluster 2 for the root dir
512 STORE_LE(info->free_clusters, (total_clust - 1));
513 STORE_LE(info->next_cluster, 2);
514 STORE_LE(info->boot_sign, BOOT_SIGN);
517 xwrite(dev, buf, bytes_per_sect * backup_boot_sector);
518 // 2nd copy and possibly zero sectors
519 xwrite(dev, buf, bytes_per_sect * (reserved_sect - backup_boot_sector));
522 { // file allocation tables
524 unsigned char *fat = (void*)buf;
526 memset(buf, 0, bytes_per_sect * 2);
527 // initial FAT entries
528 MARK_CLUSTER(0, 0x0fffff00 | media_byte);
529 MARK_CLUSTER(1, 0xffffffff);
530 // mark cluster 2 as EOF (used for root dir)
531 MARK_CLUSTER(2, EOF_FAT32);
532 for (i = 0; i < NUM_FATS; i++) {
533 xwrite(dev, buf, bytes_per_sect);
534 for (j = 1; j < sect_per_fat; j++)
535 xwrite(dev, buf + bytes_per_sect, bytes_per_sect);
540 // empty directory is just a set of zero bytes
541 memset(buf, 0, sect_per_clust * bytes_per_sect);
542 if (volume_label[0]) {
543 // create dir entry for volume_label
544 struct msdos_dir_entry *de;
550 strncpy(de->name, volume_label, sizeof(de->name));
551 STORE_LE(de->attr, ATTR_VOLUME);
553 localtime_r(&create_time, &tm_time);
554 t = (tm_time.tm_sec >> 1) + (tm_time.tm_min << 5) + (tm_time.tm_hour << 11);
555 d = tm_time.tm_mday + ((tm_time.tm_mon+1) << 5) + ((tm_time.tm_year-80) << 9);
556 STORE_LE(de->time, t);
557 STORE_LE(de->date, d);
558 //STORE_LE(de->ctime_cs, 0);
559 de->ctime = de->time;
560 de->cdate = de->date;
561 de->adate = de->date;
564 xwrite(dev, buf, sect_per_clust * bytes_per_sect);
568 uoff_t volume_size_blocks;
569 unsigned start_data_sector;
570 unsigned start_data_block;
571 unsigned badblocks = 0;
573 off_t currently_testing;
574 char *blkbuf = xmalloc(BLOCK_SIZE * TEST_BUFFER_BLOCKS);
576 volume_size_blocks = (volume_size_bytes >> BLOCK_SIZE_BITS);
577 // N.B. the two following vars are in hard sectors, i.e. SECTOR_SIZE byte sectors!
578 start_data_sector = (reserved_sect + NUM_FATS * sect_per_fat) * (bytes_per_sect / SECTOR_SIZE);
579 start_data_block = (start_data_sector + SECTORS_PER_BLOCK - 1) / SECTORS_PER_BLOCK;
581 bb_error_msg("searching for bad blocks");
582 currently_testing = 0;
583 try = TEST_BUFFER_BLOCKS;
584 while (currently_testing < volume_size_blocks) {
585 if (currently_testing + try > volume_size_blocks)
586 try = volume_size_blocks - currently_testing;
587 // perform a test on a block. return the number of blocks
588 // that could be read successfully.
589 // seek to the correct location
590 xlseek(dev, currently_testing * BLOCK_SIZE, SEEK_SET);
592 got = read(dev, blkbuf, try * BLOCK_SIZE);
595 if (got & (BLOCK_SIZE - 1))
596 bb_error_msg("unexpected values in do_check: probably bugs");
598 currently_testing += got;
600 try = TEST_BUFFER_BLOCKS;
604 if (currently_testing < start_data_block)
605 bb_error_msg_and_die("bad blocks before data-area: cannot make fs");
607 // mark all of the sectors in the block as bad
608 for (i = 0; i < SECTORS_PER_BLOCK; i++) {
609 int cluster = (currently_testing * SECTORS_PER_BLOCK + i - start_data_sector) / (int) (sect_per_clust) / (bytes_per_sect / SECTOR_SIZE);
611 bb_error_msg_and_die("invalid cluster number in mark_sector: probably bug!");
612 MARK_CLUSTER(cluster, BAD_FAT32);
619 bb_error_msg("%d bad block(s)", badblocks);
624 if (ENABLE_FEATURE_CLEAN_UP) {