1 /*
2 * initialize.c --- initialize a filesystem handle given superblock
3 * parameters. Used by mke2fs when initializing a filesystem.
4 *
5 * Copyright (C) 1994, 1995, 1996 Theodore Ts'o.
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the GNU Public
9 * License.
10 * %End-Header%
11 */
12
13 #include <stdio.h>
14 #include <string.h>
15 #if HAVE_UNISTD_H
16 #include <unistd.h>
17 #endif
18 #include <fcntl.h>
19 #include <time.h>
20 #if HAVE_SYS_STAT_H
21 #include <sys/stat.h>
22 #endif
23 #if HAVE_SYS_TYPES_H
24 #include <sys/types.h>
25 #endif
26
27 #include "ext2_fs.h"
28 #include "ext2fs.h"
29
30 #if defined(__linux__) && defined(EXT2_OS_LINUX)
31 #define CREATOR_OS EXT2_OS_LINUX
32 #else
33 #if defined(__GNU__) && defined(EXT2_OS_HURD)
34 #define CREATOR_OS EXT2_OS_HURD
35 #else
36 #if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD)
37 #define CREATOR_OS EXT2_OS_FREEBSD
38 #else
39 #if defined(LITES) && defined(EXT2_OS_LITES)
40 #define CREATOR_OS EXT2_OS_LITES
41 #else
42 #define CREATOR_OS EXT2_OS_LINUX /* by default */
43 #endif /* defined(LITES) && defined(EXT2_OS_LITES) */
44 #endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
45 #endif /* defined(__GNU__) && defined(EXT2_OS_HURD) */
46 #endif /* defined(__linux__) && defined(EXT2_OS_LINUX) */
47
48 /*
49 * Note we override the kernel include file's idea of what the default
50 * check interval (never) should be. It's a good idea to check at
51 * least *occasionally*, specially since servers will never rarely get
52 * to reboot, since Linux is so robust these days. :-)
53 *
54 * 180 days (six months) seems like a good value.
55 */
56 #ifdef EXT2_DFL_CHECKINTERVAL
57 #undef EXT2_DFL_CHECKINTERVAL
58 #endif
59 #define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
60
61 /*
62 * Calculate the number of GDT blocks to reserve for online filesystem growth.
63 * The absolute maximum number of GDT blocks we can reserve is determined by
64 * the number of block pointers that can fit into a single block.
65 */
calc_reserved_gdt_blocks(ext2_filsys fs)66 static unsigned int calc_reserved_gdt_blocks(ext2_filsys fs)
67 {
68 struct ext2_super_block *sb = fs->super;
69 unsigned long bpg = sb->s_blocks_per_group;
70 unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb);
71 unsigned long max_blocks = 0xffffffff;
72 unsigned long rsv_groups;
73 unsigned int rsv_gdb;
74
75 /* We set it at 1024x the current filesystem size, or
76 * the upper block count limit (2^32), whichever is lower.
77 */
78 if (sb->s_blocks_count < max_blocks / 1024)
79 max_blocks = sb->s_blocks_count * 1024;
80 rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg);
81 rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks;
82 if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
83 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
84 #ifdef RES_GDT_DEBUG
85 printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n",
86 max_blocks, rsv_groups, rsv_gdb);
87 #endif
88
89 return rsv_gdb;
90 }
91
ext2fs_initialize(const char * name,int flags,struct ext2_super_block * param,io_manager manager,ext2_filsys * ret_fs)92 errcode_t ext2fs_initialize(const char *name, int flags,
93 struct ext2_super_block *param,
94 io_manager manager, ext2_filsys *ret_fs)
95 {
96 ext2_filsys fs;
97 errcode_t retval;
98 struct ext2_super_block *super;
99 int frags_per_block;
100 unsigned int rem;
101 unsigned int overhead = 0;
102 unsigned int ipg;
103 dgrp_t i;
104 blk_t numblocks;
105 int rsv_gdt;
106 int csum_flag;
107 int io_flags;
108 char *buf = 0;
109 char c;
110
111 if (!param || !param->s_blocks_count)
112 return EXT2_ET_INVALID_ARGUMENT;
113
114 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
115 if (retval)
116 return retval;
117
118 memset(fs, 0, sizeof(struct struct_ext2_filsys));
119 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
120 fs->flags = flags | EXT2_FLAG_RW;
121 fs->umask = 022;
122 #ifdef WORDS_BIGENDIAN
123 fs->flags |= EXT2_FLAG_SWAP_BYTES;
124 #endif
125 io_flags = IO_FLAG_RW;
126 if (flags & EXT2_FLAG_EXCLUSIVE)
127 io_flags |= IO_FLAG_EXCLUSIVE;
128 retval = manager->open(name, io_flags, &fs->io);
129 if (retval)
130 goto cleanup;
131 fs->image_io = fs->io;
132 fs->io->app_data = fs;
133 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
134 if (retval)
135 goto cleanup;
136
137 strcpy(fs->device_name, name);
138 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
139 if (retval)
140 goto cleanup;
141 fs->super = super;
142
143 memset(super, 0, SUPERBLOCK_SIZE);
144
145 #define set_field(field, default) (super->field = param->field ? \
146 param->field : (default))
147
148 super->s_magic = EXT2_SUPER_MAGIC;
149 super->s_state = EXT2_VALID_FS;
150
151 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
152 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
153 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
154 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
155 set_field(s_errors, EXT2_ERRORS_DEFAULT);
156 set_field(s_feature_compat, 0);
157 set_field(s_feature_incompat, 0);
158 set_field(s_feature_ro_compat, 0);
159 set_field(s_first_meta_bg, 0);
160 set_field(s_raid_stride, 0); /* default stride size: 0 */
161 set_field(s_raid_stripe_width, 0); /* default stripe width: 0 */
162 set_field(s_log_groups_per_flex, 0);
163 set_field(s_flags, 0);
164 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
165 retval = EXT2_ET_UNSUPP_FEATURE;
166 goto cleanup;
167 }
168 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
169 retval = EXT2_ET_RO_UNSUPP_FEATURE;
170 goto cleanup;
171 }
172
173 set_field(s_rev_level, EXT2_GOOD_OLD_REV);
174 if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
175 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
176 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
177 if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
178 int extra_isize = sizeof(struct ext2_inode_large) -
179 EXT2_GOOD_OLD_INODE_SIZE;
180 set_field(s_min_extra_isize, extra_isize);
181 set_field(s_want_extra_isize, extra_isize);
182 }
183 } else {
184 super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
185 super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
186 }
187
188 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
189 super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
190
191 super->s_creator_os = CREATOR_OS;
192
193 fs->blocksize = EXT2_BLOCK_SIZE(super);
194 fs->fragsize = EXT2_FRAG_SIZE(super);
195 frags_per_block = fs->blocksize / fs->fragsize;
196
197 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
198 set_field(s_blocks_per_group, fs->blocksize * 8);
199 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
200 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
201 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
202
203 super->s_blocks_count = param->s_blocks_count;
204 super->s_r_blocks_count = param->s_r_blocks_count;
205 if (super->s_r_blocks_count >= param->s_blocks_count) {
206 retval = EXT2_ET_INVALID_ARGUMENT;
207 goto cleanup;
208 }
209
210 /*
211 * If we're creating an external journal device, we don't need
212 * to bother with the rest.
213 */
214 if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
215 fs->group_desc_count = 0;
216 ext2fs_mark_super_dirty(fs);
217 *ret_fs = fs;
218 return 0;
219 }
220
221 retry:
222 fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count -
223 super->s_first_data_block,
224 EXT2_BLOCKS_PER_GROUP(super));
225 if (fs->group_desc_count == 0) {
226 retval = EXT2_ET_TOOSMALL;
227 goto cleanup;
228 }
229 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
230 EXT2_DESC_PER_BLOCK(super));
231
232 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
233 set_field(s_inodes_count, super->s_blocks_count / i);
234
235 /*
236 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
237 * that we have enough inodes for the filesystem(!)
238 */
239 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
240 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
241
242 /*
243 * There should be at least as many inodes as the user
244 * requested. Figure out how many inodes per group that
245 * should be. But make sure that we don't allocate more than
246 * one bitmap's worth of inodes each group.
247 */
248 ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
249 if (ipg > fs->blocksize * 8) {
250 if (super->s_blocks_per_group >= 256) {
251 /* Try again with slightly different parameters */
252 super->s_blocks_per_group -= 8;
253 super->s_blocks_count = param->s_blocks_count;
254 super->s_frags_per_group = super->s_blocks_per_group *
255 frags_per_block;
256 goto retry;
257 } else {
258 retval = EXT2_ET_TOO_MANY_INODES;
259 goto cleanup;
260 }
261 }
262
263 if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
264 ipg = EXT2_MAX_INODES_PER_GROUP(super);
265
266 ipg_retry:
267 super->s_inodes_per_group = ipg;
268
269 /*
270 * Make sure the number of inodes per group completely fills
271 * the inode table blocks in the descriptor. If not, add some
272 * additional inodes/group. Waste not, want not...
273 */
274 fs->inode_blocks_per_group = (((super->s_inodes_per_group *
275 EXT2_INODE_SIZE(super)) +
276 EXT2_BLOCK_SIZE(super) - 1) /
277 EXT2_BLOCK_SIZE(super));
278 super->s_inodes_per_group = ((fs->inode_blocks_per_group *
279 EXT2_BLOCK_SIZE(super)) /
280 EXT2_INODE_SIZE(super));
281 /*
282 * Finally, make sure the number of inodes per group is a
283 * multiple of 8. This is needed to simplify the bitmap
284 * splicing code.
285 */
286 super->s_inodes_per_group &= ~7;
287 fs->inode_blocks_per_group = (((super->s_inodes_per_group *
288 EXT2_INODE_SIZE(super)) +
289 EXT2_BLOCK_SIZE(super) - 1) /
290 EXT2_BLOCK_SIZE(super));
291
292 /*
293 * adjust inode count to reflect the adjusted inodes_per_group
294 */
295 if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
296 ipg--;
297 goto ipg_retry;
298 }
299 super->s_inodes_count = super->s_inodes_per_group *
300 fs->group_desc_count;
301 super->s_free_inodes_count = super->s_inodes_count;
302
303 /*
304 * check the number of reserved group descriptor table blocks
305 */
306 if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
307 rsv_gdt = calc_reserved_gdt_blocks(fs);
308 else
309 rsv_gdt = 0;
310 set_field(s_reserved_gdt_blocks, rsv_gdt);
311 if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
312 retval = EXT2_ET_RES_GDT_BLOCKS;
313 goto cleanup;
314 }
315
316 /*
317 * Calculate the maximum number of bookkeeping blocks per
318 * group. It includes the superblock, the block group
319 * descriptors, the block bitmap, the inode bitmap, the inode
320 * table, and the reserved gdt blocks.
321 */
322 overhead = (int) (3 + fs->inode_blocks_per_group +
323 fs->desc_blocks + super->s_reserved_gdt_blocks);
324
325 /* This can only happen if the user requested too many inodes */
326 if (overhead > super->s_blocks_per_group) {
327 retval = EXT2_ET_TOO_MANY_INODES;
328 goto cleanup;
329 }
330
331 /*
332 * See if the last group is big enough to support the
333 * necessary data structures. If not, we need to get rid of
334 * it. We need to recalculate the overhead for the last block
335 * group, since it might or might not have a superblock
336 * backup.
337 */
338 overhead = (int) (2 + fs->inode_blocks_per_group);
339 if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
340 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
341 rem = ((super->s_blocks_count - super->s_first_data_block) %
342 super->s_blocks_per_group);
343 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
344 retval = EXT2_ET_TOOSMALL;
345 goto cleanup;
346 }
347 if (rem && (rem < overhead+50)) {
348 super->s_blocks_count -= rem;
349 goto retry;
350 }
351
352 /*
353 * At this point we know how big the filesystem will be. So
354 * we can do any and all allocations that depend on the block
355 * count.
356 */
357
358 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
359 if (retval)
360 goto cleanup;
361
362 strcpy(buf, "block bitmap for ");
363 strcat(buf, fs->device_name);
364 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
365 if (retval)
366 goto cleanup;
367
368 strcpy(buf, "inode bitmap for ");
369 strcat(buf, fs->device_name);
370 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
371 if (retval)
372 goto cleanup;
373
374 ext2fs_free_mem(&buf);
375
376 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
377 &fs->group_desc);
378 if (retval)
379 goto cleanup;
380
381 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
382
383 /*
384 * Reserve the superblock and group descriptors for each
385 * group, and fill in the correct group statistics for group.
386 * Note that although the block bitmap, inode bitmap, and
387 * inode table have not been allocated (and in fact won't be
388 * by this routine), they are accounted for nevertheless.
389 *
390 * If FLEX_BG meta-data grouping is used, only account for the
391 * superblock and group descriptors (the inode tables and
392 * bitmaps will be accounted for when allocated).
393 */
394 super->s_free_blocks_count = 0;
395 csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
396 EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
397 for (i = 0; i < fs->group_desc_count; i++) {
398 /*
399 * Don't set the BLOCK_UNINIT group for the last group
400 * because the block bitmap needs to be padded.
401 */
402 if (csum_flag) {
403 if (i != fs->group_desc_count - 1)
404 fs->group_desc[i].bg_flags |=
405 EXT2_BG_BLOCK_UNINIT;
406 fs->group_desc[i].bg_flags |= EXT2_BG_INODE_UNINIT;
407 numblocks = super->s_inodes_per_group;
408 if (i == 0)
409 numblocks -= super->s_first_ino;
410 fs->group_desc[i].bg_itable_unused = numblocks;
411 }
412 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
413 if (fs->super->s_log_groups_per_flex)
414 numblocks += 2 + fs->inode_blocks_per_group;
415
416 super->s_free_blocks_count += numblocks;
417 fs->group_desc[i].bg_free_blocks_count = numblocks;
418 fs->group_desc[i].bg_free_inodes_count =
419 fs->super->s_inodes_per_group;
420 fs->group_desc[i].bg_used_dirs_count = 0;
421 ext2fs_group_desc_csum_set(fs, i);
422 }
423
424 c = (char) 255;
425 if (((int) c) == -1) {
426 super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
427 } else {
428 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
429 }
430
431 ext2fs_mark_super_dirty(fs);
432 ext2fs_mark_bb_dirty(fs);
433 ext2fs_mark_ib_dirty(fs);
434
435 io_channel_set_blksize(fs->io, fs->blocksize);
436
437 *ret_fs = fs;
438 return 0;
439 cleanup:
440 free(buf);
441 ext2fs_free(fs);
442 return retval;
443 }
444