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 = fs->blocksize / sizeof(struct ext2_group_desc);
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 io_flags;
107 char *buf;
108 char c;
109
110 if (!param || !param->s_blocks_count)
111 return EXT2_ET_INVALID_ARGUMENT;
112
113 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
114 if (retval)
115 return retval;
116
117 memset(fs, 0, sizeof(struct struct_ext2_filsys));
118 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
119 fs->flags = flags | EXT2_FLAG_RW;
120 fs->umask = 022;
121 #ifdef WORDS_BIGENDIAN
122 fs->flags |= EXT2_FLAG_SWAP_BYTES;
123 #endif
124 io_flags = IO_FLAG_RW;
125 if (flags & EXT2_FLAG_EXCLUSIVE)
126 io_flags |= IO_FLAG_EXCLUSIVE;
127 retval = manager->open(name, io_flags, &fs->io);
128 if (retval)
129 goto cleanup;
130 fs->image_io = fs->io;
131 fs->io->app_data = fs;
132 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
133 if (retval)
134 goto cleanup;
135
136 strcpy(fs->device_name, name);
137 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
138 if (retval)
139 goto cleanup;
140 fs->super = super;
141
142 memset(super, 0, SUPERBLOCK_SIZE);
143
144 #define set_field(field, default) (super->field = param->field ? \
145 param->field : (default))
146
147 super->s_magic = EXT2_SUPER_MAGIC;
148 super->s_state = EXT2_VALID_FS;
149
150 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
151 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
152 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
153 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
154 set_field(s_errors, EXT2_ERRORS_DEFAULT);
155 set_field(s_feature_compat, 0);
156 set_field(s_feature_incompat, 0);
157 set_field(s_feature_ro_compat, 0);
158 set_field(s_first_meta_bg, 0);
159 set_field(s_raid_stride, 0); /* default stride size: 0 */
160 set_field(s_raid_stripe_width, 0); /* default stripe width: 0 */
161 set_field(s_flags, 0);
162 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
163 retval = EXT2_ET_UNSUPP_FEATURE;
164 goto cleanup;
165 }
166 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
167 retval = EXT2_ET_RO_UNSUPP_FEATURE;
168 goto cleanup;
169 }
170
171 set_field(s_rev_level, EXT2_GOOD_OLD_REV);
172 if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
173 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
174 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
175 }
176
177 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
178 super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
179
180 super->s_creator_os = CREATOR_OS;
181
182 fs->blocksize = EXT2_BLOCK_SIZE(super);
183 fs->fragsize = EXT2_FRAG_SIZE(super);
184 frags_per_block = fs->blocksize / fs->fragsize;
185
186 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
187 set_field(s_blocks_per_group, fs->blocksize * 8);
188 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
189 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
190 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
191
192 super->s_blocks_count = param->s_blocks_count;
193 super->s_r_blocks_count = param->s_r_blocks_count;
194 if (super->s_r_blocks_count >= param->s_blocks_count) {
195 retval = EXT2_ET_INVALID_ARGUMENT;
196 goto cleanup;
197 }
198
199 /*
200 * If we're creating an external journal device, we don't need
201 * to bother with the rest.
202 */
203 if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
204 fs->group_desc_count = 0;
205 ext2fs_mark_super_dirty(fs);
206 *ret_fs = fs;
207 return 0;
208 }
209
210 retry:
211 fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count -
212 super->s_first_data_block,
213 EXT2_BLOCKS_PER_GROUP(super));
214 if (fs->group_desc_count == 0) {
215 retval = EXT2_ET_TOOSMALL;
216 goto cleanup;
217 }
218 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
219 EXT2_DESC_PER_BLOCK(super));
220
221 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
222 set_field(s_inodes_count, super->s_blocks_count / i);
223
224 /*
225 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
226 * that we have enough inodes for the filesystem(!)
227 */
228 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
229 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
230
231 /*
232 * There should be at least as many inodes as the user
233 * requested. Figure out how many inodes per group that
234 * should be. But make sure that we don't allocate more than
235 * one bitmap's worth of inodes each group.
236 */
237 ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
238 if (ipg > fs->blocksize * 8) {
239 if (super->s_blocks_per_group >= 256) {
240 /* Try again with slightly different parameters */
241 super->s_blocks_per_group -= 8;
242 super->s_blocks_count = param->s_blocks_count;
243 super->s_frags_per_group = super->s_blocks_per_group *
244 frags_per_block;
245 goto retry;
246 } else
247 return EXT2_ET_TOO_MANY_INODES;
248 }
249
250 if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
251 ipg = EXT2_MAX_INODES_PER_GROUP(super);
252
253 ipg_retry:
254 super->s_inodes_per_group = ipg;
255
256 /*
257 * Make sure the number of inodes per group completely fills
258 * the inode table blocks in the descriptor. If not, add some
259 * additional inodes/group. Waste not, want not...
260 */
261 fs->inode_blocks_per_group = (((super->s_inodes_per_group *
262 EXT2_INODE_SIZE(super)) +
263 EXT2_BLOCK_SIZE(super) - 1) /
264 EXT2_BLOCK_SIZE(super));
265 super->s_inodes_per_group = ((fs->inode_blocks_per_group *
266 EXT2_BLOCK_SIZE(super)) /
267 EXT2_INODE_SIZE(super));
268 /*
269 * Finally, make sure the number of inodes per group is a
270 * multiple of 8. This is needed to simplify the bitmap
271 * splicing code.
272 */
273 super->s_inodes_per_group &= ~7;
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
279 /*
280 * adjust inode count to reflect the adjusted inodes_per_group
281 */
282 if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
283 ipg--;
284 goto ipg_retry;
285 }
286 super->s_inodes_count = super->s_inodes_per_group *
287 fs->group_desc_count;
288 super->s_free_inodes_count = super->s_inodes_count;
289
290 /*
291 * check the number of reserved group descriptor table blocks
292 */
293 if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
294 rsv_gdt = calc_reserved_gdt_blocks(fs);
295 else
296 rsv_gdt = 0;
297 set_field(s_reserved_gdt_blocks, rsv_gdt);
298 if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
299 retval = EXT2_ET_RES_GDT_BLOCKS;
300 goto cleanup;
301 }
302
303 /*
304 * Calculate the maximum number of bookkeeping blocks per
305 * group. It includes the superblock, the block group
306 * descriptors, the block bitmap, the inode bitmap, the inode
307 * table, and the reserved gdt blocks.
308 */
309 overhead = (int) (3 + fs->inode_blocks_per_group +
310 fs->desc_blocks + super->s_reserved_gdt_blocks);
311
312 /* This can only happen if the user requested too many inodes */
313 if (overhead > super->s_blocks_per_group)
314 return EXT2_ET_TOO_MANY_INODES;
315
316 /*
317 * See if the last group is big enough to support the
318 * necessary data structures. If not, we need to get rid of
319 * it. We need to recalculate the overhead for the last block
320 * group, since it might or might not have a superblock
321 * backup.
322 */
323 overhead = (int) (2 + fs->inode_blocks_per_group);
324 if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
325 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
326 rem = ((super->s_blocks_count - super->s_first_data_block) %
327 super->s_blocks_per_group);
328 if ((fs->group_desc_count == 1) && rem && (rem < overhead))
329 return EXT2_ET_TOOSMALL;
330 if (rem && (rem < overhead+50)) {
331 super->s_blocks_count -= rem;
332 goto retry;
333 }
334
335 /*
336 * At this point we know how big the filesystem will be. So
337 * we can do any and all allocations that depend on the block
338 * count.
339 */
340
341 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
342 if (retval)
343 goto cleanup;
344
345 sprintf(buf, "block bitmap for %s", fs->device_name);
346 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
347 if (retval)
348 goto cleanup;
349
350 sprintf(buf, "inode bitmap for %s", fs->device_name);
351 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
352 if (retval)
353 goto cleanup;
354
355 ext2fs_free_mem(&buf);
356
357 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
358 &fs->group_desc);
359 if (retval)
360 goto cleanup;
361
362 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
363
364 /*
365 * Reserve the superblock and group descriptors for each
366 * group, and fill in the correct group statistics for group.
367 * Note that although the block bitmap, inode bitmap, and
368 * inode table have not been allocated (and in fact won't be
369 * by this routine), they are accounted for nevertheless.
370 */
371 super->s_free_blocks_count = 0;
372 for (i = 0; i < fs->group_desc_count; i++) {
373 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
374
375 super->s_free_blocks_count += numblocks;
376 fs->group_desc[i].bg_free_blocks_count = numblocks;
377 fs->group_desc[i].bg_free_inodes_count =
378 fs->super->s_inodes_per_group;
379 fs->group_desc[i].bg_used_dirs_count = 0;
380 }
381
382 c = (char) 255;
383 if (((int) c) == -1) {
384 super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
385 } else {
386 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
387 }
388
389 ext2fs_mark_super_dirty(fs);
390 ext2fs_mark_bb_dirty(fs);
391 ext2fs_mark_ib_dirty(fs);
392
393 io_channel_set_blksize(fs->io, fs->blocksize);
394
395 *ret_fs = fs;
396 return 0;
397 cleanup:
398 ext2fs_free(fs);
399 return retval;
400 }
401