1 /* mke2fs.c - Create an ext2 filesystem image.
2 *
3 * Copyright 2006, 2007 Rob Landley <rob@landley.net>
4
5 // Still to go: "E:jJ:L:m:O:"
6 USE_MKE2FS(NEWTOY(mke2fs, "<1>2g:Fnqm#N#i#b#", TOYFLAG_SBIN))
7
8 config MKE2FS
9 bool "mke2fs"
10 default n
11 help
12 usage: mke2fs [-Fnq] [-b ###] [-N|i ###] [-m ###] device
13
14 Create an ext2 filesystem on a block device or filesystem image.
15
16 -F Force to run on a mounted device
17 -n Don't write to device
18 -q Quiet (no output)
19 -b size Block size (1024, 2048, or 4096)
20 -N inodes Allocate this many inodes
21 -i bytes Allocate one inode for every XXX bytes of device
22 -m percent Reserve this percent of filesystem space for root user
23
24 config MKE2FS_JOURNAL
25 bool "Journaling support (ext3)"
26 default n
27 depends on MKE2FS
28 help
29 usage: mke2fs [-j] [-J size=###,device=XXX]
30
31 -j Create journal (ext3)
32 -J Journal options
33 size: Number of blocks (1024-102400)
34 device: Specify an external journal
35
36 config MKE2FS_GEN
37 bool "Generate (gene2fs)"
38 default n
39 depends on MKE2FS
40 help
41 usage: gene2fs [options] device filename
42
43 The [options] are the same as mke2fs.
44
45 config MKE2FS_LABEL
46 bool "Label support"
47 default n
48 depends on MKE2FS
49 help
50 usage: mke2fs [-L label] [-M path] [-o string]
51
52 -L Volume label
53 -M Path to mount point
54 -o Created by
55
56 config MKE2FS_EXTENDED
57 bool "Extended options"
58 default n
59 depends on MKE2FS
60 help
61 usage: mke2fs [-E stride=###] [-O option[,option]]
62
63 -E stride= Set RAID stripe size (in blocks)
64 -O [opts] Specify fewer ext2 option flags (for old kernels)
65 All of these are on by default (as appropriate)
66 none Clear default options (all but journaling)
67 dir_index Use htree indexes for large directories
68 filetype Store file type info in directory entry
69 has_journal Set by -j
70 journal_dev Set by -J device=XXX
71 sparse_super Don't allocate huge numbers of redundant superblocks
72 */
73
74 #define FOR_mke2fs
75 #include "toys.h"
76
77 GLOBALS(
78 // Command line arguments.
79 long blocksize;
80 long bytes_per_inode;
81 long inodes; // Total inodes in filesystem.
82 long reserved_percent; // Integer precent of space to reserve for root.
83 char *gendir; // Where to read dirtree from.
84
85 // Internal data.
86 struct dirtree *dt; // Tree of files to copy into the new filesystem.
87 unsigned treeblocks; // Blocks used by dt
88 unsigned treeinodes; // Inodes used by dt
89
90 unsigned blocks; // Total blocks in the filesystem.
91 unsigned freeblocks; // Free blocks in the filesystem.
92 unsigned inodespg; // Inodes per group
93 unsigned groups; // Total number of block groups.
94 unsigned blockbits; // Bits per block. (Also blocks per group.)
95
96 // For gene2fs
97 unsigned nextblock; // Next data block to allocate
98 unsigned nextgroup; // Next group we'll be allocating from
99 int fsfd; // File descriptor of filesystem (to output to).
100 )
101
102 // Stuff defined in linux/ext2_fs.h
103
104 #define EXT2_SUPER_MAGIC 0xEF53
105
106 struct ext2_superblock {
107 uint32_t inodes_count; // Inodes count
108 uint32_t blocks_count; // Blocks count
109 uint32_t r_blocks_count; // Reserved blocks count
110 uint32_t free_blocks_count; // Free blocks count
111 uint32_t free_inodes_count; // Free inodes count
112 uint32_t first_data_block; // First Data Block
113 uint32_t log_block_size; // Block size
114 uint32_t log_frag_size; // Fragment size
115 uint32_t blocks_per_group; // Blocks per group
116 uint32_t frags_per_group; // Fragments per group
117 uint32_t inodes_per_group; // Inodes per group
118 uint32_t mtime; // Mount time
119 uint32_t wtime; // Write time
120 uint16_t mnt_count; // Mount count
121 uint16_t max_mnt_count; // Maximal mount count
122 uint16_t magic; // Magic signature
123 uint16_t state; // File system state
124 uint16_t errors; // Behaviour when detecting errors
125 uint16_t minor_rev_level; // minor revision level
126 uint32_t lastcheck; // time of last check
127 uint32_t checkinterval; // max. time between checks
128 uint32_t creator_os; // OS
129 uint32_t rev_level; // Revision level
130 uint16_t def_resuid; // Default uid for reserved blocks
131 uint16_t def_resgid; // Default gid for reserved blocks
132 uint32_t first_ino; // First non-reserved inode
133 uint16_t inode_size; // size of inode structure
134 uint16_t block_group_nr; // block group # of this superblock
135 uint32_t feature_compat; // compatible feature set
136 uint32_t feature_incompat; // incompatible feature set
137 uint32_t feature_ro_compat; // readonly-compatible feature set
138 char uuid[16]; // 128-bit uuid for volume
139 char volume_name[16]; // volume name
140 char last_mounted[64]; // directory where last mounted
141 uint32_t alg_usage_bitmap; // For compression
142 // For EXT2_COMPAT_PREALLOC
143 uint8_t prealloc_blocks; // Nr of blocks to try to preallocate
144 uint8_t prealloc_dir_blocks; //Nr to preallocate for dirs
145 uint16_t padding1;
146 // For EXT3_FEATURE_COMPAT_HAS_JOURNAL
147 uint8_t journal_uuid[16]; // uuid of journal superblock
148 uint32_t journal_inum; // inode number of journal file
149 uint32_t journal_dev; // device number of journal file
150 uint32_t last_orphan; // start of list of inodes to delete
151 uint32_t hash_seed[4]; // HTREE hash seed
152 uint8_t def_hash_version; // Default hash version to use
153 uint8_t padding2[3];
154 uint32_t default_mount_opts;
155 uint32_t first_meta_bg; // First metablock block group
156 uint32_t mkfs_time; // Creation timestamp
157 uint32_t jnl_blocks[17]; // Backup of journal inode
158 // uint32_t reserved[172]; // Padding to the end of the block
159 };
160
161 struct ext2_group
162 {
163 uint32_t block_bitmap; // Block number of block bitmap
164 uint32_t inode_bitmap; // Block number of inode bitmap
165 uint32_t inode_table; // Block number of inode table
166 uint16_t free_blocks_count; // How many free blocks in this group?
167 uint16_t free_inodes_count; // How many free inodes in this group?
168 uint16_t used_dirs_count; // How many directories?
169 uint16_t reserved[7]; // pad to 32 bytes
170 };
171
172 struct ext2_dentry {
173 uint32_t inode; // Inode number
174 uint16_t rec_len; // Directory entry length
175 uint8_t name_len; // Name length
176 uint8_t file_type;
177 char name[0]; // File name
178 };
179
180 struct ext2_inode {
181 uint16_t mode; // File mode
182 uint16_t uid; // Low 16 bits of Owner Uid
183 uint32_t size; // Size in bytes
184 uint32_t atime; // Access time
185 uint32_t ctime; // Creation time
186 uint32_t mtime; // Modification time
187 uint32_t dtime; // Deletion Time
188 uint16_t gid; // Low 16 bits of Group Id
189 uint16_t links_count; // Links count
190 uint32_t blocks; // Blocks count
191 uint32_t flags; // File flags
192 uint32_t reserved1;
193 uint32_t block[15]; // Pointers to blocks
194 uint32_t generation; // File version (for NFS)
195 uint32_t file_acl; // File ACL
196 uint32_t dir_acl; // Directory ACL (or top bits of file length)
197 uint32_t faddr; // Last block in file
198 uint8_t frag; // Fragment number
199 uint8_t fsize; // Fragment size
200 uint16_t pad1;
201 uint16_t uid_high; // High bits of uid
202 uint16_t gid_high; // High bits of gid
203 uint32_t reserved2;
204 };
205
206 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC 0x0001
207 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES 0x0002
208 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
209 #define EXT2_FEATURE_COMPAT_EXT_ATTR 0x0008
210 #define EXT2_FEATURE_COMPAT_RESIZE_INO 0x0010
211 #define EXT2_FEATURE_COMPAT_DIR_INDEX 0x0020
212
213 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
214 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
215 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
216
217 #define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001
218 #define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
219 #define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004
220 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
221 #define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
222
223 #define EXT2_NAME_LEN 255
224
225 // Ext2 directory file types. Only the low 3 bits are used. The
226 // other bits are reserved for now.
227
228 enum {
229 EXT2_FT_UNKNOWN,
230 EXT2_FT_REG_FILE,
231 EXT2_FT_DIR,
232 EXT2_FT_CHRDEV,
233 EXT2_FT_BLKDEV,
234 EXT2_FT_FIFO,
235 EXT2_FT_SOCK,
236 EXT2_FT_SYMLINK,
237 EXT2_FT_MAX
238 };
239
240 #define INODES_RESERVED 10
241
div_round_up(uint32_t a,uint32_t b)242 static uint32_t div_round_up(uint32_t a, uint32_t b)
243 {
244 uint32_t c = a/b;
245
246 if (a%b) c++;
247 return c;
248 }
249
250 // Calculate data blocks plus index blocks needed to hold a file.
251
file_blocks_used(uint64_t size,uint32_t * blocklist)252 static uint32_t file_blocks_used(uint64_t size, uint32_t *blocklist)
253 {
254 uint32_t dblocks = (uint32_t)((size+(TT.blocksize-1))/TT.blocksize);
255 uint32_t idx=TT.blocksize/4, iblocks=0, diblocks=0, tiblocks=0;
256
257 // Fill out index blocks in inode.
258
259 if (blocklist) {
260 int i;
261
262 // Direct index blocks
263 for (i=0; i<13 && i<dblocks; i++) blocklist[i] = i;
264 // Singly indirect index blocks
265 if (dblocks > 13+idx) blocklist[13] = 13+idx;
266 // Doubly indirect index blocks
267 idx = 13 + idx + (idx*idx);
268 if (dblocks > idx) blocklist[14] = idx;
269
270 return 0;
271 }
272
273 // Account for direct, singly, doubly, and triply indirect index blocks
274
275 if (dblocks > 12) {
276 iblocks = ((dblocks-13)/idx)+1;
277 if (iblocks > 1) {
278 diblocks = ((iblocks-2)/idx)+1;
279 if (diblocks > 1)
280 tiblocks = ((diblocks-2)/idx)+1;
281 }
282 }
283
284 return dblocks + iblocks + diblocks + tiblocks;
285 }
286
287 // Use the parent pointer to iterate through the tree non-recursively.
treenext(struct dirtree * this)288 static struct dirtree *treenext(struct dirtree *this)
289 {
290 while (this && !this->next) this = this->parent;
291 if (this) this = this->next;
292
293 return this;
294 }
295
296 // Recursively calculate the number of blocks used by each inode in the tree.
297 // Returns blocks used by this directory, assigns bytes used to *size.
298 // Writes total block count to TT.treeblocks and inode count to TT.treeinodes.
299
check_treesize(struct dirtree * that,off_t * size)300 static long check_treesize(struct dirtree *that, off_t *size)
301 {
302 long blocks;
303
304 while (that) {
305 *size += sizeof(struct ext2_dentry) + strlen(that->name);
306
307 if (that->child)
308 that->st.st_blocks = check_treesize(that->child, &that->st.st_size);
309 else if (S_ISREG(that->st.st_mode)) {
310 that->st.st_blocks = file_blocks_used(that->st.st_size, 0);
311 TT.treeblocks += that->st.st_blocks;
312 }
313 that = that->next;
314 }
315 TT.treeblocks += blocks = file_blocks_used(*size, 0);
316 TT.treeinodes++;
317
318 return blocks;
319 }
320
321 // Calculate inode numbers and link counts.
322 //
323 // To do this right I need to copy the tree and sort it, but here's a really
324 // ugly n^2 way of dealing with the problem that doesn't scale well to large
325 // numbers of files (> 100,000) but can be done in very little code.
326 // This rewrites inode numbers to their final values, allocating depth first.
327
check_treelinks(struct dirtree * tree)328 static void check_treelinks(struct dirtree *tree)
329 {
330 struct dirtree *current=tree, *that;
331 long inode = INODES_RESERVED;
332
333 while (current) {
334 ++inode;
335 // Since we can't hardlink to directories, we know their link count.
336 if (S_ISDIR(current->st.st_mode)) current->st.st_nlink = 2;
337 else {
338 dev_t new = current->st.st_dev;
339
340 if (!new) continue;
341
342 // Look for other copies of current node
343 current->st.st_nlink = 0;
344 for (that = tree; that; that = treenext(that)) {
345 if (current->st.st_ino == that->st.st_ino &&
346 current->st.st_dev == that->st.st_dev)
347 {
348 current->st.st_nlink++;
349 current->st.st_ino = inode;
350 }
351 }
352 }
353 current->st.st_ino = inode;
354 current = treenext(current);
355 }
356 }
357
358 // Calculate inodes per group from total inodes.
get_inodespg(uint32_t inodes)359 static uint32_t get_inodespg(uint32_t inodes)
360 {
361 uint32_t temp;
362
363 // Round up to fill complete inode blocks.
364 temp = (inodes + TT.groups - 1) / TT.groups;
365 inodes = TT.blocksize/sizeof(struct ext2_inode);
366 return ((temp + inodes - 1)/inodes)*inodes;
367 }
368
369 // Fill out superblock and TT structures.
370
init_superblock(struct ext2_superblock * sb)371 static void init_superblock(struct ext2_superblock *sb)
372 {
373 uint32_t temp;
374
375 // Set log_block_size and log_frag_size.
376
377 for (temp = 0; temp < 4; temp++) if (TT.blocksize == 1024<<temp) break;
378 if (temp==4) error_exit("bad blocksize");
379 sb->log_block_size = sb->log_frag_size = SWAP_LE32(temp);
380
381 // Fill out blocks_count, r_blocks_count, first_data_block
382
383 sb->blocks_count = SWAP_LE32(TT.blocks);
384 sb->free_blocks_count = SWAP_LE32(TT.freeblocks);
385 temp = (TT.blocks * (uint64_t)TT.reserved_percent) / 100;
386 sb->r_blocks_count = SWAP_LE32(temp);
387
388 sb->first_data_block = SWAP_LE32(TT.blocksize == 1024 ? 1 : 0);
389
390 // Set blocks_per_group and frags_per_group, which is the size of an
391 // allocation bitmap that fits in one block (I.E. how many bits per block)?
392
393 sb->blocks_per_group = sb->frags_per_group = SWAP_LE32(TT.blockbits);
394
395 // Set inodes_per_group and total inodes_count
396 sb->inodes_per_group = SWAP_LE32(TT.inodespg);
397 sb->inodes_count = SWAP_LE32(TT.inodespg * TT.groups);
398
399 // Determine free inodes.
400 temp = TT.inodespg*TT.groups - INODES_RESERVED;
401 if (temp < TT.treeinodes) error_exit("Not enough inodes.\n");
402 sb->free_inodes_count = SWAP_LE32(temp - TT.treeinodes);
403
404 // Fill out the rest of the superblock.
405 sb->max_mnt_count=0xFFFF;
406 sb->wtime = sb->lastcheck = sb->mkfs_time = SWAP_LE32(time(NULL));
407 sb->magic = SWAP_LE32(0xEF53);
408 sb->state = sb->errors = SWAP_LE16(1);
409
410 sb->rev_level = SWAP_LE32(1);
411 sb->first_ino = SWAP_LE32(INODES_RESERVED+1);
412 sb->inode_size = SWAP_LE16(sizeof(struct ext2_inode));
413 sb->feature_incompat = SWAP_LE32(EXT2_FEATURE_INCOMPAT_FILETYPE);
414 sb->feature_ro_compat = SWAP_LE32(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER);
415
416 create_uuid(sb->uuid);
417
418 // TODO If we're called as mke3fs or mkfs.ext3, do a journal.
419
420 //if (strchr(toys.which->name,'3'))
421 // sb->feature_compat |= SWAP_LE32(EXT3_FEATURE_COMPAT_HAS_JOURNAL);
422 }
423
424 // Does this group contain a superblock backup (and group descriptor table)?
is_sb_group(uint32_t group)425 static int is_sb_group(uint32_t group)
426 {
427 int i;
428
429 // Superblock backups are on groups 0, 1, and powers of 3, 5, and 7.
430 if(!group || group==1) return 1;
431 for (i=3; i<9; i+=2) {
432 int j = i;
433 while (j<group) j*=i;
434 if (j==group) return 1;
435 }
436 return 0;
437 }
438
439
440 // Number of blocks used in group by optional superblock/group list backup.
group_superblock_overhead(uint32_t group)441 static int group_superblock_overhead(uint32_t group)
442 {
443 int used;
444
445 if (!is_sb_group(group)) return 0;
446
447 // How many blocks does the group descriptor table take up?
448 used = TT.groups * sizeof(struct ext2_group);
449 used += TT.blocksize - 1;
450 used /= TT.blocksize;
451 // Plus the superblock itself.
452 used++;
453 // And a corner case.
454 if (!group && TT.blocksize == 1024) used++;
455
456 return used;
457 }
458
459 // Number of blocks used in group to store superblock/group/inode list
group_overhead(uint32_t group)460 static int group_overhead(uint32_t group)
461 {
462 // Return superblock backup overhead (if any), plus block/inode
463 // allocation bitmaps, plus inode tables.
464 return group_superblock_overhead(group) + 2 + get_inodespg(TT.inodespg)
465 / (TT.blocksize/sizeof(struct ext2_inode));
466 }
467
468 // In bitmap "array" set "len" bits starting at position "start" (from 0).
bits_set(char * array,int start,int len)469 static void bits_set(char *array, int start, int len)
470 {
471 while(len) {
472 if ((start&7) || len<8) {
473 array[start/8]|=(1<<(start&7));
474 start++;
475 len--;
476 } else {
477 array[start/8]=255;
478 start+=8;
479 len-=8;
480 }
481 }
482 }
483
484 // Seek past len bytes (to maintain sparse file), or write zeroes if output
485 // not seekable
put_zeroes(int len)486 static void put_zeroes(int len)
487 {
488 if(-1 == lseek(TT.fsfd, len, SEEK_SET)) {
489 memset(toybuf, 0, sizeof(toybuf));
490 while (len) {
491 int out = len > sizeof(toybuf) ? sizeof(toybuf) : len;
492 xwrite(TT.fsfd, toybuf, out);
493 len -= out;
494 }
495 }
496 }
497
498 // Fill out an inode structure from struct stat info in dirtree.
fill_inode(struct ext2_inode * in,struct dirtree * that)499 static void fill_inode(struct ext2_inode *in, struct dirtree *that)
500 {
501 uint32_t fbu[15];
502 int temp;
503
504 file_blocks_used(that->st.st_size, fbu);
505
506 // If that inode needs data blocks allocated to it.
507 if (that->st.st_size) {
508 int i, group = TT.nextblock/TT.blockbits;
509
510 // TODO: teach this about indirect blocks.
511 for (i=0; i<15; i++) {
512 // If we just jumped into a new group, skip group overhead blocks.
513 while (group >= TT.nextgroup)
514 TT.nextblock += group_overhead(TT.nextgroup++);
515 }
516 }
517 // TODO : S_ISREG/DIR/CHR/BLK/FIFO/LNK/SOCK(m)
518 in->mode = SWAP_LE32(that->st.st_mode);
519
520 in->uid = SWAP_LE16(that->st.st_uid & 0xFFFF);
521 in->uid_high = SWAP_LE16(that->st.st_uid >> 16);
522 in->gid = SWAP_LE16(that->st.st_gid & 0xFFFF);
523 in->gid_high = SWAP_LE16(that->st.st_gid >> 16);
524 in->size = SWAP_LE32(that->st.st_size & 0xFFFFFFFF);
525
526 // Contortions to make the compiler not generate a warning for x>>32
527 // when x is 32 bits. The optimizer should clean this up.
528 if (sizeof(that->st.st_size) > 4) temp = 32;
529 else temp = 0;
530 if (temp) in->dir_acl = SWAP_LE32(that->st.st_size >> temp);
531
532 in->atime = SWAP_LE32(that->st.st_atime);
533 in->ctime = SWAP_LE32(that->st.st_ctime);
534 in->mtime = SWAP_LE32(that->st.st_mtime);
535
536 in->links_count = SWAP_LE16(that->st.st_nlink);
537 in->blocks = SWAP_LE32(that->st.st_blocks);
538 // in->faddr
539 }
540
541 // Works like an archiver.
542 // The first argument is the name of the file to create. If it already
543 // exists, that size will be used.
544
mke2fs_main(void)545 void mke2fs_main(void)
546 {
547 int i, temp;
548 off_t length;
549 uint32_t usedblocks, usedinodes, dtiblk, dtbblk;
550 struct dirtree *dti, *dtb;
551 struct ext2_superblock sb;
552
553 // Handle command line arguments.
554
555 if (toys.optargs[1]) {
556 sscanf(toys.optargs[1], "%u", &TT.blocks);
557 temp = O_RDWR|O_CREAT;
558 } else temp = O_RDWR;
559 if (!TT.reserved_percent) TT.reserved_percent = 5;
560
561 // TODO: Check if filesystem is mounted here
562
563 // For mke?fs, open file. For gene?fs, create file.
564 TT.fsfd = xcreate(*toys.optargs, temp, 0777);
565
566 // Determine appropriate block size and block count from file length.
567 // (If no length, default to 4k. They can override it on the cmdline.)
568
569 length = fdlength(TT.fsfd);
570 if (!TT.blocksize) TT.blocksize = (length && length < 1<<29) ? 1024 : 4096;
571 TT.blockbits = 8*TT.blocksize;
572 if (!TT.blocks) TT.blocks = length/TT.blocksize;
573
574 // Collect gene2fs list or lost+found, calculate requirements.
575
576 if (TT.gendir) {
577 strncpy(toybuf, TT.gendir, sizeof(toybuf));
578 dti = dirtree_read(toybuf, dirtree_notdotdot);
579 } else {
580 dti = xzalloc(sizeof(struct dirtree)+11);
581 strcpy(dti->name, "lost+found");
582 dti->st.st_mode = S_IFDIR|0755;
583 dti->st.st_ctime = dti->st.st_mtime = time(NULL);
584 }
585
586 // Add root directory inode. This is iterated through for when finding
587 // blocks, but not when finding inodes. The tree's parent pointers don't
588 // point back into this.
589
590 dtb = xzalloc(sizeof(struct dirtree)+1);
591 dtb->st.st_mode = S_IFDIR|0755;
592 dtb->st.st_ctime = dtb->st.st_mtime = time(NULL);
593 dtb->child = dti;
594
595 // Figure out how much space is used by preset files
596 length = check_treesize(dtb, &(dtb->st.st_size));
597 check_treelinks(dtb);
598
599 // Figure out how many total inodes we need.
600
601 if (!TT.inodes) {
602 if (!TT.bytes_per_inode) TT.bytes_per_inode = 8192;
603 TT.inodes = (TT.blocks * (uint64_t)TT.blocksize) / TT.bytes_per_inode;
604 }
605
606 // If we're generating a filesystem and have no idea how many blocks it
607 // needs, start with a minimal guess, find the overhead of that many
608 // groups, and loop until this is enough groups to store this many blocks.
609 if (!TT.blocks) TT.groups = (TT.treeblocks/TT.blockbits)+1;
610 else TT.groups = div_round_up(TT.blocks, TT.blockbits);
611
612 for (;;) {
613 temp = TT.treeblocks;
614
615 for (i = 0; i<TT.groups; i++) temp += group_overhead(i);
616
617 if (TT.blocks) {
618 if (TT.blocks < temp) error_exit("Not enough space.\n");
619 break;
620 }
621 if (temp <= TT.groups * TT.blockbits) {
622 TT.blocks = temp;
623 break;
624 }
625 TT.groups++;
626 }
627 TT.freeblocks = TT.blocks - temp;
628
629 // Now we know all the TT data, initialize superblock structure.
630
631 init_superblock(&sb);
632
633 // Start writing. Skip the first 1k to avoid the boot sector (if any).
634 put_zeroes(1024);
635
636 // Loop through block groups, write out each one.
637 dtiblk = dtbblk = usedblocks = usedinodes = 0;
638 for (i=0; i<TT.groups; i++) {
639 struct ext2_inode *in = (struct ext2_inode *)toybuf;
640 uint32_t start, itable, used, end;
641 int j, slot;
642
643 // Where does this group end?
644 end = TT.blockbits;
645 if ((i+1)*TT.blockbits > TT.blocks) end = TT.blocks & (TT.blockbits-1);
646
647 // Blocks used by inode table
648 itable = (TT.inodespg*sizeof(struct ext2_inode))/TT.blocksize;
649
650 // If a superblock goes here, write it out.
651 start = group_superblock_overhead(i);
652 if (start) {
653 struct ext2_group *bg = (struct ext2_group *)toybuf;
654 int treeblocks = TT.treeblocks, treeinodes = TT.treeinodes;
655
656 sb.block_group_nr = SWAP_LE16(i);
657
658 // Write superblock and pad it up to block size
659 xwrite(TT.fsfd, &sb, sizeof(struct ext2_superblock));
660 temp = TT.blocksize - sizeof(struct ext2_superblock);
661 if (!i && TT.blocksize > 1024) temp -= 1024;
662 memset(toybuf, 0, TT.blocksize);
663 xwrite(TT.fsfd, toybuf, temp);
664
665 // Loop through groups to write group descriptor table.
666 for(j=0; j<TT.groups; j++) {
667
668 // Figure out what sector this group starts in.
669 used = group_superblock_overhead(j);
670
671 // Find next array slot in this block (flush block if full).
672 slot = j % (TT.blocksize/sizeof(struct ext2_group));
673 if (!slot) {
674 if (j) xwrite(TT.fsfd, bg, TT.blocksize);
675 memset(bg, 0, TT.blocksize);
676 }
677
678 // How many free inodes in this group?
679 temp = TT.inodespg;
680 if (!i) temp -= INODES_RESERVED;
681 if (temp > treeinodes) {
682 treeinodes -= temp;
683 temp = 0;
684 } else {
685 temp -= treeinodes;
686 treeinodes = 0;
687 }
688 bg[slot].free_inodes_count = SWAP_LE16(temp);
689
690 // How many free blocks in this group?
691 temp = TT.inodespg/(TT.blocksize/sizeof(struct ext2_inode)) + 2;
692 temp = end-used-temp;
693 if (temp > treeblocks) {
694 treeblocks -= temp;
695 temp = 0;
696 } else {
697 temp -= treeblocks;
698 treeblocks = 0;
699 }
700 bg[slot].free_blocks_count = SWAP_LE32(temp);
701
702 // Fill out rest of group structure
703 used += j*TT.blockbits;
704 bg[slot].block_bitmap = SWAP_LE32(used++);
705 bg[slot].inode_bitmap = SWAP_LE32(used++);
706 bg[slot].inode_table = SWAP_LE32(used);
707 bg[slot].used_dirs_count = 0; // (TODO)
708 }
709 xwrite(TT.fsfd, bg, TT.blocksize);
710 }
711
712 // Now write out stuff that every block group has.
713
714 // Write block usage bitmap
715
716 start += 2 + itable;
717 memset(toybuf, 0, TT.blocksize);
718 bits_set(toybuf, 0, start);
719 bits_set(toybuf, end, TT.blockbits-end);
720 temp = TT.treeblocks - usedblocks;
721 if (temp) {
722 if (end-start > temp) temp = end-start;
723 bits_set(toybuf, start, temp);
724 }
725 xwrite(TT.fsfd, toybuf, TT.blocksize);
726
727 // Write inode bitmap
728 memset(toybuf, 0, TT.blocksize);
729 j = 0;
730 if (!i) bits_set(toybuf, 0, j = INODES_RESERVED);
731 bits_set(toybuf, TT.inodespg, slot = TT.blockbits-TT.inodespg);
732 temp = TT.treeinodes - usedinodes;
733 if (temp) {
734 if (slot-j > temp) temp = slot-j;
735 bits_set(toybuf, j, temp);
736 }
737 xwrite(TT.fsfd, toybuf, TT.blocksize);
738
739 // Write inode table for this group (TODO)
740 for (j = 0; j<TT.inodespg; j++) {
741 slot = j % (TT.blocksize/sizeof(struct ext2_inode));
742 if (!slot) {
743 if (j) xwrite(TT.fsfd, in, TT.blocksize);
744 memset(in, 0, TT.blocksize);
745 }
746 if (!i && j<INODES_RESERVED) {
747 // Write root inode
748 if (j == 2) fill_inode(in+slot, dtb);
749 } else if (dti) {
750 fill_inode(in+slot, dti);
751 dti = treenext(dti);
752 }
753 }
754 xwrite(TT.fsfd, in, TT.blocksize);
755
756 while (dtb) {
757 // TODO write index data block
758 // TODO write root directory data block
759 // TODO write directory data block
760 // TODO write file data block
761 put_zeroes(TT.blocksize);
762 start++;
763 if (start == end) break;
764 }
765 // Write data blocks (TODO)
766 put_zeroes((end-start) * TT.blocksize);
767 }
768 }
769