summaryrefslogtreecommitdiff
path: root/e2fsprogs/old_e2fsprogs/ext2fs/initialize.c
blob: ef1d3437979e22158a11ab07c905c0fd44ff3e39 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
/* vi: set sw=4 ts=4: */
/*
 * initialize.c --- initialize a filesystem handle given superblock
 *	parameters.  Used by mke2fs when initializing a filesystem.
 *
 * Copyright (C) 1994, 1995, 1996 Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 */

#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <time.h>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#include "ext2_fs.h"
#include "ext2fs.h"

#if defined(__linux__)    &&	defined(EXT2_OS_LINUX)
#define CREATOR_OS EXT2_OS_LINUX
#else
#if defined(__GNU__)     &&	defined(EXT2_OS_HURD)
#define CREATOR_OS EXT2_OS_HURD
#else
#if defined(__FreeBSD__) &&	defined(EXT2_OS_FREEBSD)
#define CREATOR_OS EXT2_OS_FREEBSD
#else
#if defined(LITES)	   &&	defined(EXT2_OS_LITES)
#define CREATOR_OS EXT2_OS_LITES
#else
#define CREATOR_OS EXT2_OS_LINUX /* by default */
#endif /* defined(LITES) && defined(EXT2_OS_LITES) */
#endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
#endif /* defined(__GNU__)     && defined(EXT2_OS_HURD) */
#endif /* defined(__linux__)   && defined(EXT2_OS_LINUX) */

/*
 * Note we override the kernel include file's idea of what the default
 * check interval (never) should be.  It's a good idea to check at
 * least *occasionally*, specially since servers will never rarely get
 * to reboot, since Linux is so robust these days.  :-)
 *
 * 180 days (six months) seems like a good value.
 */
#ifdef EXT2_DFL_CHECKINTERVAL
#undef EXT2_DFL_CHECKINTERVAL
#endif
#define EXT2_DFL_CHECKINTERVAL (86400L * 180L)

/*
 * Calculate the number of GDT blocks to reserve for online filesystem growth.
 * The absolute maximum number of GDT blocks we can reserve is determined by
 * the number of block pointers that can fit into a single block.
 */
static int calc_reserved_gdt_blocks(ext2_filsys fs)
{
	struct ext2_super_block *sb = fs->super;
	unsigned long bpg = sb->s_blocks_per_group;
	unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc);
	unsigned long max_blocks = 0xffffffff;
	unsigned long rsv_groups;
	int rsv_gdb;

	/* We set it at 1024x the current filesystem size, or
	 * the upper block count limit (2^32), whichever is lower.
	 */
	if (sb->s_blocks_count < max_blocks / 1024)
		max_blocks = sb->s_blocks_count * 1024;
	rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg;
	rsv_gdb = (rsv_groups + gdpb - 1) / gdpb - fs->desc_blocks;
	if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
		rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
#ifdef RES_GDT_DEBUG
	printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %lu\n",
	       max_blocks, rsv_groups, rsv_gdb);
#endif

	return rsv_gdb;
}

errcode_t ext2fs_initialize(const char *name, int flags,
			    struct ext2_super_block *param,
			    io_manager manager, ext2_filsys *ret_fs)
{
	ext2_filsys	fs;
	errcode_t	retval;
	struct ext2_super_block *super;
	int		frags_per_block;
	unsigned int	rem;
	unsigned int	overhead = 0;
	blk_t		group_block;
	unsigned int	ipg;
	dgrp_t		i;
	blk_t		numblocks;
	int		rsv_gdt;
	char		*buf;

	if (!param || !param->s_blocks_count)
		return EXT2_ET_INVALID_ARGUMENT;

	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
	if (retval)
		return retval;

	memset(fs, 0, sizeof(struct struct_ext2_filsys));
	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
	fs->flags = flags | EXT2_FLAG_RW;
	fs->umask = 022;
#ifdef WORDS_BIGENDIAN
	fs->flags |= EXT2_FLAG_SWAP_BYTES;
#endif
	retval = manager->open(name, IO_FLAG_RW, &fs->io);
	if (retval)
		goto cleanup;
	fs->image_io = fs->io;
	fs->io->app_data = fs;
	retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
	if (retval)
		goto cleanup;

	strcpy(fs->device_name, name);
	retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
	if (retval)
		goto cleanup;
	fs->super = super;

	memset(super, 0, SUPERBLOCK_SIZE);

#define set_field(field, default) (super->field = param->field ? \
				   param->field : (default))

	super->s_magic = EXT2_SUPER_MAGIC;
	super->s_state = EXT2_VALID_FS;

	set_field(s_log_block_size, 0);	/* default blocksize: 1024 bytes */
	set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
	set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
	set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
	set_field(s_errors, EXT2_ERRORS_DEFAULT);
	set_field(s_feature_compat, 0);
	set_field(s_feature_incompat, 0);
	set_field(s_feature_ro_compat, 0);
	set_field(s_first_meta_bg, 0);
	if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
		retval = EXT2_ET_UNSUPP_FEATURE;
		goto cleanup;
	}
	if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
		retval = EXT2_ET_RO_UNSUPP_FEATURE;
		goto cleanup;
	}

	set_field(s_rev_level, EXT2_GOOD_OLD_REV);
	if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
		set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
		set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
	}

	set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
	super->s_mkfs_time = super->s_lastcheck = time(NULL);

	super->s_creator_os = CREATOR_OS;

	fs->blocksize = EXT2_BLOCK_SIZE(super);
	fs->fragsize = EXT2_FRAG_SIZE(super);
	frags_per_block = fs->blocksize / fs->fragsize;

	/* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
	set_field(s_blocks_per_group, fs->blocksize * 8);
	if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
		super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
	super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;

	super->s_blocks_count = param->s_blocks_count;
	super->s_r_blocks_count = param->s_r_blocks_count;
	if (super->s_r_blocks_count >= param->s_blocks_count) {
		retval = EXT2_ET_INVALID_ARGUMENT;
		goto cleanup;
	}

	/*
	 * If we're creating an external journal device, we don't need
	 * to bother with the rest.
	 */
	if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
		fs->group_desc_count = 0;
		ext2fs_mark_super_dirty(fs);
		*ret_fs = fs;
		return 0;
	}

retry:
	fs->group_desc_count = (super->s_blocks_count -
				super->s_first_data_block +
				EXT2_BLOCKS_PER_GROUP(super) - 1)
		/ EXT2_BLOCKS_PER_GROUP(super);
	if (fs->group_desc_count == 0) {
		retval = EXT2_ET_TOOSMALL;
		goto cleanup;
	}
	fs->desc_blocks = (fs->group_desc_count +
			   EXT2_DESC_PER_BLOCK(super) - 1)
		/ EXT2_DESC_PER_BLOCK(super);

	i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
	set_field(s_inodes_count, super->s_blocks_count / i);

	/*
	 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
	 * that we have enough inodes for the filesystem(!)
	 */
	if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
		super->s_inodes_count = EXT2_FIRST_INODE(super)+1;

	/*
	 * There should be at least as many inodes as the user
	 * requested.  Figure out how many inodes per group that
	 * should be.  But make sure that we don't allocate more than
	 * one bitmap's worth of inodes each group.
	 */
	ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
		fs->group_desc_count;
	if (ipg > fs->blocksize * 8) {
		if (super->s_blocks_per_group >= 256) {
			/* Try again with slightly different parameters */
			super->s_blocks_per_group -= 8;
			super->s_blocks_count = param->s_blocks_count;
			super->s_frags_per_group = super->s_blocks_per_group *
				frags_per_block;
			goto retry;
		} else
			return EXT2_ET_TOO_MANY_INODES;
	}

	if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
		ipg = EXT2_MAX_INODES_PER_GROUP(super);

	super->s_inodes_per_group = ipg;
	if (super->s_inodes_count > ipg * fs->group_desc_count)
		super->s_inodes_count = ipg * fs->group_desc_count;

	/*
	 * Make sure the number of inodes per group completely fills
	 * the inode table blocks in the descriptor.  If not, add some
	 * additional inodes/group.  Waste not, want not...
	 */
	fs->inode_blocks_per_group = (((super->s_inodes_per_group *
					EXT2_INODE_SIZE(super)) +
				       EXT2_BLOCK_SIZE(super) - 1) /
				      EXT2_BLOCK_SIZE(super));
	super->s_inodes_per_group = ((fs->inode_blocks_per_group *
				      EXT2_BLOCK_SIZE(super)) /
				     EXT2_INODE_SIZE(super));
	/*
	 * Finally, make sure the number of inodes per group is a
	 * multiple of 8.  This is needed to simplify the bitmap
	 * splicing code.
	 */
	super->s_inodes_per_group &= ~7;
	fs->inode_blocks_per_group = (((super->s_inodes_per_group *
					EXT2_INODE_SIZE(super)) +
				       EXT2_BLOCK_SIZE(super) - 1) /
				      EXT2_BLOCK_SIZE(super));

	/*
	 * adjust inode count to reflect the adjusted inodes_per_group
	 */
	super->s_inodes_count = super->s_inodes_per_group *
		fs->group_desc_count;
	super->s_free_inodes_count = super->s_inodes_count;

	/*
	 * check the number of reserved group descriptor table blocks
	 */
	if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
		rsv_gdt = calc_reserved_gdt_blocks(fs);
	else
		rsv_gdt = 0;
	set_field(s_reserved_gdt_blocks, rsv_gdt);
	if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
		retval = EXT2_ET_RES_GDT_BLOCKS;
		goto cleanup;
	}

	/*
	 * Overhead is the number of bookkeeping blocks per group.  It
	 * includes the superblock backup, the group descriptor
	 * backups, the inode bitmap, the block bitmap, and the inode
	 * table.
	 */

	overhead = (int) (2 + fs->inode_blocks_per_group);

	if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
		overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;

	/* This can only happen if the user requested too many inodes */
	if (overhead > super->s_blocks_per_group)
		return EXT2_ET_TOO_MANY_INODES;

	/*
	 * See if the last group is big enough to support the
	 * necessary data structures.  If not, we need to get rid of
	 * it.
	 */
	rem = ((super->s_blocks_count - super->s_first_data_block) %
	       super->s_blocks_per_group);
	if ((fs->group_desc_count == 1) && rem && (rem < overhead))
		return EXT2_ET_TOOSMALL;
	if (rem && (rem < overhead+50)) {
		super->s_blocks_count -= rem;
		goto retry;
	}

	/*
	 * At this point we know how big the filesystem will be.  So
	 * we can do any and all allocations that depend on the block
	 * count.
	 */

	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
	if (retval)
		goto cleanup;

	sprintf(buf, "block bitmap for %s", fs->device_name);
	retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
	if (retval)
		goto cleanup;

	sprintf(buf, "inode bitmap for %s", fs->device_name);
	retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
	if (retval)
		goto cleanup;

	ext2fs_free_mem(&buf);

	retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
				&fs->group_desc);
	if (retval)
		goto cleanup;

	memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);

	/*
	 * Reserve the superblock and group descriptors for each
	 * group, and fill in the correct group statistics for group.
	 * Note that although the block bitmap, inode bitmap, and
	 * inode table have not been allocated (and in fact won't be
	 * by this routine), they are accounted for nevertheless.
	 */
	group_block = super->s_first_data_block;
	super->s_free_blocks_count = 0;
	for (i = 0; i < fs->group_desc_count; i++) {
		numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);

		super->s_free_blocks_count += numblocks;
		fs->group_desc[i].bg_free_blocks_count = numblocks;
		fs->group_desc[i].bg_free_inodes_count =
			fs->super->s_inodes_per_group;
		fs->group_desc[i].bg_used_dirs_count = 0;

		group_block += super->s_blocks_per_group;
	}

	ext2fs_mark_super_dirty(fs);
	ext2fs_mark_bb_dirty(fs);
	ext2fs_mark_ib_dirty(fs);

	io_channel_set_blksize(fs->io, fs->blocksize);

	*ret_fs = fs;
	return 0;
cleanup:
	ext2fs_free(fs);
	return retval;
}