Contents of /tags/mkinitrd-6_2_2/busybox/util-linux/mkfs_ext2.c
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Sun May 30 12:33:03 2010 UTC (14 years, 3 months ago) by niro
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Sun May 30 12:33:03 2010 UTC (14 years, 3 months ago) by niro
File MIME type: text/plain
File size: 23991 byte(s)
tagged 'mkinitrd-6_2_2'
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * mkfs_ext2: utility to create EXT2 filesystem |
4 | * inspired by genext2fs |
5 | * |
6 | * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com> |
7 | * |
8 | * Licensed under GPLv2, see file LICENSE in this tarball for details. |
9 | */ |
10 | #include "libbb.h" |
11 | #include <linux/fs.h> |
12 | #include <linux/ext2_fs.h> |
13 | #include "volume_id/volume_id_internal.h" |
14 | |
15 | #define ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT 0 |
16 | #define ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX 1 |
17 | |
18 | // from e2fsprogs |
19 | #define s_reserved_gdt_blocks s_padding1 |
20 | #define s_mkfs_time s_reserved[0] |
21 | #define s_flags s_reserved[22] |
22 | |
23 | #define EXT2_HASH_HALF_MD4 1 |
24 | #define EXT2_FLAGS_SIGNED_HASH 0x0001 |
25 | #define EXT2_FLAGS_UNSIGNED_HASH 0x0002 |
26 | |
27 | // storage helpers |
28 | char BUG_wrong_field_size(void); |
29 | #define STORE_LE(field, value) \ |
30 | do { \ |
31 | if (sizeof(field) == 4) \ |
32 | field = cpu_to_le32(value); \ |
33 | else if (sizeof(field) == 2) \ |
34 | field = cpu_to_le16(value); \ |
35 | else if (sizeof(field) == 1) \ |
36 | field = (value); \ |
37 | else \ |
38 | BUG_wrong_field_size(); \ |
39 | } while (0) |
40 | |
41 | #define FETCH_LE32(field) \ |
42 | (sizeof(field) == 4 ? cpu_to_le32(field) : BUG_wrong_field_size()) |
43 | |
44 | // All fields are little-endian |
45 | struct ext2_dir { |
46 | uint32_t inode1; |
47 | uint16_t rec_len1; |
48 | uint8_t name_len1; |
49 | uint8_t file_type1; |
50 | char name1[4]; |
51 | uint32_t inode2; |
52 | uint16_t rec_len2; |
53 | uint8_t name_len2; |
54 | uint8_t file_type2; |
55 | char name2[4]; |
56 | uint32_t inode3; |
57 | uint16_t rec_len3; |
58 | uint8_t name_len3; |
59 | uint8_t file_type3; |
60 | char name3[12]; |
61 | }; |
62 | |
63 | static unsigned int_log2(unsigned arg) |
64 | { |
65 | unsigned r = 0; |
66 | while ((arg >>= 1) != 0) |
67 | r++; |
68 | return r; |
69 | } |
70 | |
71 | // taken from mkfs_minix.c. libbb candidate? |
72 | // "uint32_t size", since we never use it for anything >32 bits |
73 | static uint32_t div_roundup(uint32_t size, uint32_t n) |
74 | { |
75 | // Overflow-resistant |
76 | uint32_t res = size / n; |
77 | if (res * n != size) |
78 | res++; |
79 | return res; |
80 | } |
81 | |
82 | static void allocate(uint8_t *bitmap, uint32_t blocksize, uint32_t start, uint32_t end) |
83 | { |
84 | uint32_t i; |
85 | |
86 | //bb_info_msg("ALLOC: [%u][%u][%u]: [%u-%u]:=[%x],[%x]", blocksize, start, end, start/8, blocksize - end/8 - 1, (1 << (start & 7)) - 1, (uint8_t)(0xFF00 >> (end & 7))); |
87 | memset(bitmap, 0, blocksize); |
88 | i = start / 8; |
89 | memset(bitmap, 0xFF, i); |
90 | bitmap[i] = (1 << (start & 7)) - 1; //0..7 => 00000000..01111111 |
91 | i = end / 8; |
92 | bitmap[blocksize - i - 1] |= 0x7F00 >> (end & 7); //0..7 => 00000000..11111110 |
93 | memset(bitmap + blocksize - i, 0xFF, i); // N.B. no overflow here! |
94 | } |
95 | |
96 | static uint32_t has_super(uint32_t x) |
97 | { |
98 | // 0, 1 and powers of 3, 5, 7 up to 2^32 limit |
99 | static const uint32_t supers[] = { |
100 | 0, 1, 3, 5, 7, 9, 25, 27, 49, 81, 125, 243, 343, 625, 729, |
101 | 2187, 2401, 3125, 6561, 15625, 16807, 19683, 59049, 78125, |
102 | 117649, 177147, 390625, 531441, 823543, 1594323, 1953125, |
103 | 4782969, 5764801, 9765625, 14348907, 40353607, 43046721, |
104 | 48828125, 129140163, 244140625, 282475249, 387420489, |
105 | 1162261467, 1220703125, 1977326743, 3486784401/* >2^31 */, |
106 | }; |
107 | const uint32_t *sp = supers + ARRAY_SIZE(supers); |
108 | while (1) { |
109 | sp--; |
110 | if (x == *sp) |
111 | return 1; |
112 | if (x > *sp) |
113 | return 0; |
114 | } |
115 | } |
116 | |
117 | #define fd 3 /* predefined output descriptor */ |
118 | |
119 | static void PUT(uint64_t off, void *buf, uint32_t size) |
120 | { |
121 | // bb_info_msg("PUT[%llu]:[%u]", off, size); |
122 | xlseek(fd, off, SEEK_SET); |
123 | xwrite(fd, buf, size); |
124 | } |
125 | |
126 | // 128 and 256-byte inodes: |
127 | // 128-byte inode is described by struct ext2_inode. |
128 | // 256-byte one just has these fields appended: |
129 | // __u16 i_extra_isize; |
130 | // __u16 i_pad1; |
131 | // __u32 i_ctime_extra; /* extra Change time (nsec << 2 | epoch) */ |
132 | // __u32 i_mtime_extra; /* extra Modification time (nsec << 2 | epoch) */ |
133 | // __u32 i_atime_extra; /* extra Access time (nsec << 2 | epoch) */ |
134 | // __u32 i_crtime; /* File creation time */ |
135 | // __u32 i_crtime_extra; /* extra File creation time (nsec << 2 | epoch)*/ |
136 | // __u32 i_version_hi; /* high 32 bits for 64-bit version */ |
137 | // the rest is padding. |
138 | // |
139 | // linux/ext2_fs.h has "#define i_size_high i_dir_acl" which suggests that even |
140 | // 128-byte inode is capable of describing large files (i_dir_acl is meaningful |
141 | // only for directories, which never need i_size_high). |
142 | // |
143 | // Standard mke2fs creates a filesystem with 256-byte inodes if it is |
144 | // bigger than 0.5GB. So far, we do not do this. |
145 | |
146 | // Standard mke2fs 1.41.9: |
147 | // Usage: mke2fs [-c|-l filename] [-b block-size] [-f fragment-size] |
148 | // [-i bytes-per-inode] [-I inode-size] [-J journal-options] |
149 | // [-G meta group size] [-N number-of-inodes] |
150 | // [-m reserved-blocks-percentage] [-o creator-os] |
151 | // [-g blocks-per-group] [-L volume-label] [-M last-mounted-directory] |
152 | // [-O feature[,...]] [-r fs-revision] [-E extended-option[,...]] |
153 | // [-T fs-type] [-U UUID] [-jnqvFSV] device [blocks-count] |
154 | // |
155 | // Options not commented below are taken but silently ignored: |
156 | enum { |
157 | OPT_c = 1 << 0, |
158 | OPT_l = 1 << 1, |
159 | OPT_b = 1 << 2, // block size, in bytes |
160 | OPT_f = 1 << 3, |
161 | OPT_i = 1 << 4, // bytes per inode |
162 | OPT_I = 1 << 5, // custom inode size, in bytes |
163 | OPT_J = 1 << 6, |
164 | OPT_G = 1 << 7, |
165 | OPT_N = 1 << 8, |
166 | OPT_m = 1 << 9, // percentage of blocks reserved for superuser |
167 | OPT_o = 1 << 10, |
168 | OPT_g = 1 << 11, |
169 | OPT_L = 1 << 12, // label |
170 | OPT_M = 1 << 13, |
171 | OPT_O = 1 << 14, |
172 | OPT_r = 1 << 15, |
173 | OPT_E = 1 << 16, |
174 | OPT_T = 1 << 17, |
175 | OPT_U = 1 << 18, |
176 | OPT_j = 1 << 19, |
177 | OPT_n = 1 << 20, // dry run: do not write anything |
178 | OPT_q = 1 << 21, |
179 | OPT_v = 1 << 22, |
180 | OPT_F = 1 << 23, |
181 | OPT_S = 1 << 24, |
182 | //OPT_V = 1 << 25, // -V version. bbox applets don't support that |
183 | }; |
184 | |
185 | int mkfs_ext2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
186 | int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) |
187 | { |
188 | unsigned i, pos, n; |
189 | unsigned bs, bpi; |
190 | unsigned blocksize, blocksize_log2; |
191 | unsigned inodesize, user_inodesize; |
192 | unsigned reserved_percent = 5; |
193 | unsigned long long kilobytes; |
194 | uint32_t nblocks, nblocks_full; |
195 | uint32_t nreserved; |
196 | uint32_t ngroups; |
197 | uint32_t bytes_per_inode; |
198 | uint32_t first_block; |
199 | uint32_t inodes_per_group; |
200 | uint32_t group_desc_blocks; |
201 | uint32_t inode_table_blocks; |
202 | uint32_t lost_and_found_blocks; |
203 | time_t timestamp; |
204 | const char *label = ""; |
205 | struct stat st; |
206 | struct ext2_super_block *sb; // superblock |
207 | struct ext2_group_desc *gd; // group descriptors |
208 | struct ext2_inode *inode; |
209 | struct ext2_dir *dir; |
210 | uint8_t *buf; |
211 | |
212 | // using global "option_mask32" instead of local "opts": |
213 | // we are register starved here |
214 | opt_complementary = "-1:b+:m+:i+"; |
215 | /*opts =*/ getopt32(argv, "cl:b:f:i:I:J:G:N:m:o:g:L:M:O:r:E:T:U:jnqvFS", |
216 | NULL, &bs, NULL, &bpi, &user_inodesize, NULL, NULL, NULL, |
217 | &reserved_percent, NULL, NULL, &label, NULL, NULL, NULL, NULL, NULL, NULL); |
218 | argv += optind; // argv[0] -- device |
219 | |
220 | // check the device is a block device |
221 | xmove_fd(xopen(argv[0], O_WRONLY), fd); |
222 | fstat(fd, &st); |
223 | if (!S_ISBLK(st.st_mode) && !(option_mask32 & OPT_F)) |
224 | bb_error_msg_and_die("not a block device"); |
225 | |
226 | // check if it is mounted |
227 | // N.B. what if we format a file? find_mount_point will return false negative since |
228 | // it is loop block device which mounted! |
229 | if (find_mount_point(argv[0], 0)) |
230 | bb_error_msg_and_die("can't format mounted filesystem"); |
231 | |
232 | // open the device, get size in kbytes |
233 | if (argv[1]) { |
234 | kilobytes = xatoull(argv[1]); |
235 | // seek past end fails on block devices but works on files |
236 | if (lseek(fd, kilobytes * 1024 - 1, SEEK_SET) != (off_t)-1) { |
237 | if (!(option_mask32 & OPT_n)) |
238 | xwrite(fd, "", 1); // file grows if needed |
239 | } |
240 | //else { |
241 | // bb_error_msg("warning, block device is smaller"); |
242 | //} |
243 | } else { |
244 | kilobytes = (uoff_t)xlseek(fd, 0, SEEK_END) / 1024; |
245 | } |
246 | |
247 | bytes_per_inode = 16384; |
248 | if (kilobytes < 512*1024) |
249 | bytes_per_inode = 4096; |
250 | if (kilobytes < 3*1024) |
251 | bytes_per_inode = 8192; |
252 | if (option_mask32 & OPT_i) |
253 | bytes_per_inode = bpi; |
254 | |
255 | // Determine block size and inode size |
256 | // block size is a multiple of 1024 |
257 | // inode size is a multiple of 128 |
258 | blocksize = 1024; |
259 | inodesize = sizeof(struct ext2_inode); // 128 |
260 | if (kilobytes >= 512*1024) { // mke2fs 1.41.9 compat |
261 | blocksize = 4096; |
262 | inodesize = 256; |
263 | } |
264 | if (EXT2_MAX_BLOCK_SIZE > 4096) { |
265 | // kilobytes >> 22 == size in 4gigabyte chunks. |
266 | // if size >= 16k gigs, blocksize must be increased. |
267 | // Try "mke2fs -F image $((16 * 1024*1024*1024))" |
268 | while ((kilobytes >> 22) >= blocksize) |
269 | blocksize *= 2; |
270 | } |
271 | if (option_mask32 & OPT_b) |
272 | blocksize = bs; |
273 | if (blocksize < EXT2_MIN_BLOCK_SIZE |
274 | || blocksize > EXT2_MAX_BLOCK_SIZE |
275 | || (blocksize & (blocksize - 1)) // not power of 2 |
276 | ) { |
277 | bb_error_msg_and_die("blocksize %u is bad", blocksize); |
278 | } |
279 | // Do we have custom inode size? |
280 | if (option_mask32 & OPT_I) { |
281 | if (user_inodesize < sizeof(*inode) |
282 | || user_inodesize > blocksize |
283 | || (user_inodesize & (user_inodesize - 1)) // not power of 2 |
284 | ) { |
285 | bb_error_msg("-%c is bad", 'I'); |
286 | } else { |
287 | inodesize = user_inodesize; |
288 | } |
289 | } |
290 | |
291 | if ((int32_t)bytes_per_inode < blocksize) |
292 | bb_error_msg_and_die("-%c is bad", 'i'); |
293 | // number of bits in one block, i.e. 8*blocksize |
294 | #define blocks_per_group (8 * blocksize) |
295 | first_block = (EXT2_MIN_BLOCK_SIZE == blocksize); |
296 | blocksize_log2 = int_log2(blocksize); |
297 | |
298 | // Determine number of blocks |
299 | kilobytes >>= (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE); |
300 | nblocks = kilobytes; |
301 | if (nblocks != kilobytes) |
302 | bb_error_msg_and_die("block count doesn't fit in 32 bits"); |
303 | #define kilobytes kilobytes_unused_after_this |
304 | // Experimentally, standard mke2fs won't work on images smaller than 60k |
305 | if (nblocks < 60) |
306 | bb_error_msg_and_die("need >= 60 blocks"); |
307 | |
308 | // How many reserved blocks? |
309 | if (reserved_percent > 50) |
310 | bb_error_msg_and_die("-%c is bad", 'm'); |
311 | nreserved = (uint64_t)nblocks * reserved_percent / 100; |
312 | |
313 | // N.B. killing e2fsprogs feature! Unused blocks don't account in calculations |
314 | nblocks_full = nblocks; |
315 | |
316 | // If last block group is too small, nblocks may be decreased in order |
317 | // to discard it, and control returns here to recalculate some |
318 | // parameters. |
319 | // Note: blocksize and bytes_per_inode are never recalculated. |
320 | retry: |
321 | // N.B. a block group can have no more than blocks_per_group blocks |
322 | ngroups = div_roundup(nblocks - first_block, blocks_per_group); |
323 | |
324 | group_desc_blocks = div_roundup(ngroups, blocksize / sizeof(*gd)); |
325 | // TODO: reserved blocks must be marked as such in the bitmaps, |
326 | // or resulting filesystem is corrupt |
327 | if (ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT) { |
328 | /* |
329 | * From e2fsprogs: Calculate the number of GDT blocks to reserve for online |
330 | * filesystem growth. |
331 | * The absolute maximum number of GDT blocks we can reserve is determined by |
332 | * the number of block pointers that can fit into a single block. |
333 | * We set it at 1024x the current filesystem size, or |
334 | * the upper block count limit (2^32), whichever is lower. |
335 | */ |
336 | uint32_t reserved_group_desc_blocks = 0xFFFFFFFF; // maximum block number |
337 | if (nblocks < reserved_group_desc_blocks / 1024) |
338 | reserved_group_desc_blocks = nblocks * 1024; |
339 | reserved_group_desc_blocks = div_roundup(reserved_group_desc_blocks - first_block, blocks_per_group); |
340 | reserved_group_desc_blocks = div_roundup(reserved_group_desc_blocks, blocksize / sizeof(*gd)) - group_desc_blocks; |
341 | if (reserved_group_desc_blocks > blocksize / sizeof(uint32_t)) |
342 | reserved_group_desc_blocks = blocksize / sizeof(uint32_t); |
343 | //TODO: STORE_LE(sb->s_reserved_gdt_blocks, reserved_group_desc_blocks); |
344 | group_desc_blocks += reserved_group_desc_blocks; |
345 | } |
346 | |
347 | { |
348 | // N.B. e2fsprogs does as follows! |
349 | uint32_t overhead, remainder; |
350 | // ninodes is the max number of inodes in this filesystem |
351 | uint32_t ninodes = ((uint64_t) nblocks_full * blocksize) / bytes_per_inode; |
352 | if (ninodes < EXT2_GOOD_OLD_FIRST_INO+1) |
353 | ninodes = EXT2_GOOD_OLD_FIRST_INO+1; |
354 | inodes_per_group = div_roundup(ninodes, ngroups); |
355 | // minimum number because the first EXT2_GOOD_OLD_FIRST_INO-1 are reserved |
356 | if (inodes_per_group < 16) |
357 | inodes_per_group = 16; |
358 | // a block group can't have more inodes than blocks |
359 | if (inodes_per_group > blocks_per_group) |
360 | inodes_per_group = blocks_per_group; |
361 | // adjust inodes per group so they completely fill the inode table blocks in the descriptor |
362 | inodes_per_group = (div_roundup(inodes_per_group * inodesize, blocksize) * blocksize) / inodesize; |
363 | // make sure the number of inodes per group is a multiple of 8 |
364 | inodes_per_group &= ~7; |
365 | inode_table_blocks = div_roundup(inodes_per_group * inodesize, blocksize); |
366 | |
367 | // to be useful, lost+found should occupy at least 2 blocks (but not exceeding 16*1024 bytes), |
368 | // and at most EXT2_NDIR_BLOCKS. So reserve these blocks right now |
369 | /* Or e2fsprogs comment verbatim (what does it mean?): |
370 | * Ensure that lost+found is at least 2 blocks, so we always |
371 | * test large empty blocks for big-block filesystems. */ |
372 | lost_and_found_blocks = MIN(EXT2_NDIR_BLOCKS, 16 >> (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE)); |
373 | |
374 | // the last group needs more attention: isn't it too small for possible overhead? |
375 | overhead = (has_super(ngroups - 1) ? (1/*sb*/ + group_desc_blocks) : 0) + 1/*bbmp*/ + 1/*ibmp*/ + inode_table_blocks; |
376 | remainder = (nblocks - first_block) % blocks_per_group; |
377 | ////can't happen, nblocks >= 60 guarantees this |
378 | ////if ((1 == ngroups) |
379 | //// && remainder |
380 | //// && (remainder < overhead + 1/* "/" */ + lost_and_found_blocks) |
381 | ////) { |
382 | //// bb_error_msg_and_die("way small device"); |
383 | ////} |
384 | |
385 | // Standard mke2fs uses 50. Looks like a bug in our calculation |
386 | // of "remainder" or "overhead" - we don't match standard mke2fs |
387 | // when we transition from one group to two groups |
388 | // (a bit after 8M image size), but it works for two->three groups |
389 | // transition (at 16M). |
390 | if (remainder && (remainder < overhead + 50)) { |
391 | //bb_info_msg("CHOP[%u]", remainder); |
392 | nblocks -= remainder; |
393 | goto retry; |
394 | } |
395 | } |
396 | |
397 | if (nblocks_full - nblocks) |
398 | printf("warning: %u blocks unused\n\n", nblocks_full - nblocks); |
399 | printf( |
400 | "Filesystem label=%s\n" |
401 | "OS type: Linux\n" |
402 | "Block size=%u (log=%u)\n" |
403 | "Fragment size=%u (log=%u)\n" |
404 | "%u inodes, %u blocks\n" |
405 | "%u blocks (%u%%) reserved for the super user\n" |
406 | "First data block=%u\n" |
407 | "Maximum filesystem blocks=%u\n" |
408 | "%u block groups\n" |
409 | "%u blocks per group, %u fragments per group\n" |
410 | "%u inodes per group" |
411 | , label |
412 | , blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE |
413 | , blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE |
414 | , inodes_per_group * ngroups, nblocks |
415 | , nreserved, reserved_percent |
416 | , first_block |
417 | , group_desc_blocks * (blocksize / (unsigned)sizeof(*gd)) * blocks_per_group |
418 | , ngroups |
419 | , blocks_per_group, blocks_per_group |
420 | , inodes_per_group |
421 | ); |
422 | { |
423 | const char *fmt = "\nSuperblock backups stored on blocks:\n" |
424 | "\t%u"; |
425 | pos = first_block; |
426 | for (i = 1; i < ngroups; i++) { |
427 | pos += blocks_per_group; |
428 | if (has_super(i)) { |
429 | printf(fmt, (unsigned)pos); |
430 | fmt = ", %u"; |
431 | } |
432 | } |
433 | } |
434 | bb_putchar('\n'); |
435 | |
436 | if (option_mask32 & OPT_n) { |
437 | if (ENABLE_FEATURE_CLEAN_UP) |
438 | close(fd); |
439 | return EXIT_SUCCESS; |
440 | } |
441 | |
442 | // TODO: 3/5 refuse if mounted |
443 | // TODO: 4/5 compat options |
444 | // TODO: 1/5 sanity checks |
445 | // TODO: 0/5 more verbose error messages |
446 | // TODO: 4/5 bigendianness: recheck, wait for ARM reporters |
447 | // TODO: 2/5 reserved GDT: how to mark but not allocate? |
448 | // TODO: 3/5 dir_index? |
449 | |
450 | // fill the superblock |
451 | sb = xzalloc(1024); |
452 | STORE_LE(sb->s_rev_level, EXT2_DYNAMIC_REV); // revision 1 filesystem |
453 | STORE_LE(sb->s_magic, EXT2_SUPER_MAGIC); |
454 | STORE_LE(sb->s_inode_size, inodesize); |
455 | // set "Required extra isize" and "Desired extra isize" fields to 28 |
456 | if (inodesize != sizeof(*inode)) |
457 | STORE_LE(sb->s_reserved[21], 0x001C001C); |
458 | STORE_LE(sb->s_first_ino, EXT2_GOOD_OLD_FIRST_INO); |
459 | STORE_LE(sb->s_log_block_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE); |
460 | STORE_LE(sb->s_log_frag_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE); |
461 | // first 1024 bytes of the device are for boot record. If block size is 1024 bytes, then |
462 | // the first block is 1, otherwise 0 |
463 | STORE_LE(sb->s_first_data_block, first_block); |
464 | // block and inode bitmaps occupy no more than one block, so maximum number of blocks is |
465 | STORE_LE(sb->s_blocks_per_group, blocks_per_group); |
466 | STORE_LE(sb->s_frags_per_group, blocks_per_group); |
467 | // blocks |
468 | STORE_LE(sb->s_blocks_count, nblocks); |
469 | // reserve blocks for superuser |
470 | STORE_LE(sb->s_r_blocks_count, nreserved); |
471 | // ninodes |
472 | STORE_LE(sb->s_inodes_per_group, inodes_per_group); |
473 | STORE_LE(sb->s_inodes_count, inodes_per_group * ngroups); |
474 | STORE_LE(sb->s_free_inodes_count, inodes_per_group * ngroups - EXT2_GOOD_OLD_FIRST_INO); |
475 | // timestamps |
476 | timestamp = time(NULL); |
477 | STORE_LE(sb->s_mkfs_time, timestamp); |
478 | STORE_LE(sb->s_wtime, timestamp); |
479 | STORE_LE(sb->s_lastcheck, timestamp); |
480 | // misc. Values are chosen to match mke2fs 1.41.9 |
481 | STORE_LE(sb->s_state, 1); // TODO: what's 1? |
482 | STORE_LE(sb->s_creator_os, EXT2_OS_LINUX); |
483 | STORE_LE(sb->s_checkinterval, 24*60*60 * 180); // 180 days |
484 | STORE_LE(sb->s_errors, EXT2_ERRORS_DEFAULT); |
485 | // mke2fs 1.41.9 also sets EXT3_FEATURE_COMPAT_RESIZE_INODE |
486 | // and if >= 0.5GB, EXT3_FEATURE_RO_COMPAT_LARGE_FILE. |
487 | // we use values which match "mke2fs -O ^resize_inode": |
488 | // in this case 1.41.9 never sets EXT3_FEATURE_RO_COMPAT_LARGE_FILE. |
489 | STORE_LE(sb->s_feature_compat, EXT2_FEATURE_COMPAT_SUPP |
490 | | (EXT2_FEATURE_COMPAT_RESIZE_INO * ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT) |
491 | | (EXT2_FEATURE_COMPAT_DIR_INDEX * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX) |
492 | ); |
493 | STORE_LE(sb->s_feature_incompat, EXT2_FEATURE_INCOMPAT_FILETYPE); |
494 | STORE_LE(sb->s_feature_ro_compat, EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER); |
495 | STORE_LE(sb->s_flags, EXT2_FLAGS_UNSIGNED_HASH * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX); |
496 | generate_uuid(sb->s_uuid); |
497 | if (ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX) { |
498 | STORE_LE(sb->s_def_hash_version, EXT2_HASH_HALF_MD4); |
499 | generate_uuid((uint8_t *)sb->s_hash_seed); |
500 | } |
501 | /* |
502 | * From e2fsprogs: add "jitter" to the superblock's check interval so that we |
503 | * don't check all the filesystems at the same time. We use a |
504 | * kludgy hack of using the UUID to derive a random jitter value. |
505 | */ |
506 | STORE_LE(sb->s_max_mnt_count, |
507 | EXT2_DFL_MAX_MNT_COUNT |
508 | + (sb->s_uuid[ARRAY_SIZE(sb->s_uuid)-1] % EXT2_DFL_MAX_MNT_COUNT)); |
509 | |
510 | // write the label |
511 | safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name)); |
512 | |
513 | // calculate filesystem skeleton structures |
514 | gd = xzalloc(group_desc_blocks * blocksize); |
515 | buf = xmalloc(blocksize); |
516 | sb->s_free_blocks_count = 0; |
517 | for (i = 0, pos = first_block, n = nblocks - first_block; |
518 | i < ngroups; |
519 | i++, pos += blocks_per_group, n -= blocks_per_group |
520 | ) { |
521 | uint32_t overhead = pos + (has_super(i) ? (1/*sb*/ + group_desc_blocks) : 0); |
522 | uint32_t free_blocks; |
523 | // fill group descriptors |
524 | STORE_LE(gd[i].bg_block_bitmap, overhead + 0); |
525 | STORE_LE(gd[i].bg_inode_bitmap, overhead + 1); |
526 | STORE_LE(gd[i].bg_inode_table, overhead + 2); |
527 | overhead = overhead - pos + 1/*bbmp*/ + 1/*ibmp*/ + inode_table_blocks; |
528 | gd[i].bg_free_inodes_count = inodes_per_group; |
529 | //STORE_LE(gd[i].bg_used_dirs_count, 0); |
530 | // N.B. both "/" and "/lost+found" are within the first block group |
531 | // "/" occupies 1 block, "/lost+found" occupies lost_and_found_blocks... |
532 | if (0 == i) { |
533 | // ... thus increased overhead for the first block group ... |
534 | overhead += 1 + lost_and_found_blocks; |
535 | // ... and 2 used directories |
536 | STORE_LE(gd[i].bg_used_dirs_count, 2); |
537 | // well known reserved inodes belong to the first block too |
538 | gd[i].bg_free_inodes_count -= EXT2_GOOD_OLD_FIRST_INO; |
539 | } |
540 | |
541 | // cache free block count of the group |
542 | free_blocks = (n < blocks_per_group ? n : blocks_per_group) - overhead; |
543 | |
544 | // mark preallocated blocks as allocated |
545 | //bb_info_msg("ALLOC: [%u][%u][%u]", blocksize, overhead, blocks_per_group - (free_blocks + overhead)); |
546 | allocate(buf, blocksize, |
547 | // reserve "overhead" blocks |
548 | overhead, |
549 | // mark unused trailing blocks |
550 | blocks_per_group - (free_blocks + overhead) |
551 | ); |
552 | // dump block bitmap |
553 | PUT((uint64_t)(FETCH_LE32(gd[i].bg_block_bitmap)) * blocksize, buf, blocksize); |
554 | STORE_LE(gd[i].bg_free_blocks_count, free_blocks); |
555 | |
556 | // mark preallocated inodes as allocated |
557 | allocate(buf, blocksize, |
558 | // mark reserved inodes |
559 | inodes_per_group - gd[i].bg_free_inodes_count, |
560 | // mark unused trailing inodes |
561 | blocks_per_group - inodes_per_group |
562 | ); |
563 | // dump inode bitmap |
564 | //PUT((uint64_t)(FETCH_LE32(gd[i].bg_block_bitmap)) * blocksize, buf, blocksize); |
565 | //but it's right after block bitmap, so we can just: |
566 | xwrite(fd, buf, blocksize); |
567 | STORE_LE(gd[i].bg_free_inodes_count, gd[i].bg_free_inodes_count); |
568 | |
569 | // count overall free blocks |
570 | sb->s_free_blocks_count += free_blocks; |
571 | } |
572 | STORE_LE(sb->s_free_blocks_count, sb->s_free_blocks_count); |
573 | |
574 | // dump filesystem skeleton structures |
575 | // printf("Writing superblocks and filesystem accounting information: "); |
576 | for (i = 0, pos = first_block; i < ngroups; i++, pos += blocks_per_group) { |
577 | // dump superblock and group descriptors and their backups |
578 | if (has_super(i)) { |
579 | // N.B. 1024 byte blocks are special |
580 | PUT(((uint64_t)pos * blocksize) + ((0 == i && 1024 != blocksize) ? 1024 : 0), |
581 | sb, 1024); |
582 | PUT(((uint64_t)pos * blocksize) + blocksize, |
583 | gd, group_desc_blocks * blocksize); |
584 | } |
585 | } |
586 | |
587 | // zero boot sectors |
588 | memset(buf, 0, blocksize); |
589 | PUT(0, buf, 1024); // N.B. 1024 <= blocksize, so buf[0..1023] contains zeros |
590 | // zero inode tables |
591 | for (i = 0; i < ngroups; ++i) |
592 | for (n = 0; n < inode_table_blocks; ++n) |
593 | PUT((uint64_t)(FETCH_LE32(gd[i].bg_inode_table) + n) * blocksize, |
594 | buf, blocksize); |
595 | |
596 | // prepare directory inode |
597 | inode = (struct ext2_inode *)buf; |
598 | STORE_LE(inode->i_mode, S_IFDIR | S_IRWXU | S_IRGRP | S_IROTH | S_IXGRP | S_IXOTH); |
599 | STORE_LE(inode->i_mtime, timestamp); |
600 | STORE_LE(inode->i_atime, timestamp); |
601 | STORE_LE(inode->i_ctime, timestamp); |
602 | STORE_LE(inode->i_size, blocksize); |
603 | // inode->i_blocks stores the number of 512 byte data blocks |
604 | // (512, because it goes directly to struct stat without scaling) |
605 | STORE_LE(inode->i_blocks, blocksize / 512); |
606 | |
607 | // dump root dir inode |
608 | STORE_LE(inode->i_links_count, 3); // "/.", "/..", "/lost+found/.." point to this inode |
609 | STORE_LE(inode->i_block[0], FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks); |
610 | PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_ROOT_INO-1) * inodesize, |
611 | buf, inodesize); |
612 | |
613 | // dump lost+found dir inode |
614 | STORE_LE(inode->i_links_count, 2); // both "/lost+found" and "/lost+found/." point to this inode |
615 | STORE_LE(inode->i_size, lost_and_found_blocks * blocksize); |
616 | STORE_LE(inode->i_blocks, (lost_and_found_blocks * blocksize) / 512); |
617 | n = FETCH_LE32(inode->i_block[0]) + 1; |
618 | for (i = 0; i < lost_and_found_blocks; ++i) |
619 | STORE_LE(inode->i_block[i], i + n); // use next block |
620 | //bb_info_msg("LAST BLOCK USED[%u]", i + n); |
621 | PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_GOOD_OLD_FIRST_INO-1) * inodesize, |
622 | buf, inodesize); |
623 | |
624 | // dump directories |
625 | memset(buf, 0, blocksize); |
626 | dir = (struct ext2_dir *)buf; |
627 | |
628 | // dump 2nd+ blocks of "/lost+found" |
629 | STORE_LE(dir->rec_len1, blocksize); // e2fsck 1.41.4 compat (1.41.9 does not need this) |
630 | for (i = 1; i < lost_and_found_blocks; ++i) |
631 | PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 1+i) * blocksize, |
632 | buf, blocksize); |
633 | |
634 | // dump 1st block of "/lost+found" |
635 | STORE_LE(dir->inode1, EXT2_GOOD_OLD_FIRST_INO); |
636 | STORE_LE(dir->rec_len1, 12); |
637 | STORE_LE(dir->name_len1, 1); |
638 | STORE_LE(dir->file_type1, EXT2_FT_DIR); |
639 | dir->name1[0] = '.'; |
640 | STORE_LE(dir->inode2, EXT2_ROOT_INO); |
641 | STORE_LE(dir->rec_len2, blocksize - 12); |
642 | STORE_LE(dir->name_len2, 2); |
643 | STORE_LE(dir->file_type2, EXT2_FT_DIR); |
644 | dir->name2[0] = '.'; dir->name2[1] = '.'; |
645 | PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 1) * blocksize, buf, blocksize); |
646 | |
647 | // dump root dir block |
648 | STORE_LE(dir->inode1, EXT2_ROOT_INO); |
649 | STORE_LE(dir->rec_len2, 12); |
650 | STORE_LE(dir->inode3, EXT2_GOOD_OLD_FIRST_INO); |
651 | STORE_LE(dir->rec_len3, blocksize - 12 - 12); |
652 | STORE_LE(dir->name_len3, 10); |
653 | STORE_LE(dir->file_type3, EXT2_FT_DIR); |
654 | strcpy(dir->name3, "lost+found"); |
655 | PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 0) * blocksize, buf, blocksize); |
656 | |
657 | // cleanup |
658 | if (ENABLE_FEATURE_CLEAN_UP) { |
659 | free(buf); |
660 | free(gd); |
661 | free(sb); |
662 | } |
663 | |
664 | xclose(fd); |
665 | return EXIT_SUCCESS; |
666 | } |