blob: 240335b32e7b425077c21f9f79f1e1a42d913bd1
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * initialize.c --- initialize a filesystem handle given superblock |
4 | * parameters. Used by mke2fs when initializing a filesystem. |
5 | * |
6 | * Copyright (C) 1994, 1995, 1996 Theodore Ts'o. |
7 | * |
8 | * %Begin-Header% |
9 | * This file may be redistributed under the terms of the GNU Public |
10 | * License. |
11 | * %End-Header% |
12 | */ |
13 | |
14 | #include <stdio.h> |
15 | #include <string.h> |
16 | #if HAVE_UNISTD_H |
17 | #include <unistd.h> |
18 | #endif |
19 | #include <fcntl.h> |
20 | #include <time.h> |
21 | #if HAVE_SYS_STAT_H |
22 | #include <sys/stat.h> |
23 | #endif |
24 | #if HAVE_SYS_TYPES_H |
25 | #include <sys/types.h> |
26 | #endif |
27 | |
28 | #include "ext2_fs.h" |
29 | #include "ext2fs.h" |
30 | |
31 | #if defined(__linux__) && defined(EXT2_OS_LINUX) |
32 | #define CREATOR_OS EXT2_OS_LINUX |
33 | #else |
34 | #if defined(__GNU__) && defined(EXT2_OS_HURD) |
35 | #define CREATOR_OS EXT2_OS_HURD |
36 | #else |
37 | #if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) |
38 | #define CREATOR_OS EXT2_OS_FREEBSD |
39 | #else |
40 | #if defined(LITES) && defined(EXT2_OS_LITES) |
41 | #define CREATOR_OS EXT2_OS_LITES |
42 | #else |
43 | #define CREATOR_OS EXT2_OS_LINUX /* by default */ |
44 | #endif /* defined(LITES) && defined(EXT2_OS_LITES) */ |
45 | #endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */ |
46 | #endif /* defined(__GNU__) && defined(EXT2_OS_HURD) */ |
47 | #endif /* defined(__linux__) && defined(EXT2_OS_LINUX) */ |
48 | |
49 | /* |
50 | * Note we override the kernel include file's idea of what the default |
51 | * check interval (never) should be. It's a good idea to check at |
52 | * least *occasionally*, specially since servers will never rarely get |
53 | * to reboot, since Linux is so robust these days. :-) |
54 | * |
55 | * 180 days (six months) seems like a good value. |
56 | */ |
57 | #ifdef EXT2_DFL_CHECKINTERVAL |
58 | #undef EXT2_DFL_CHECKINTERVAL |
59 | #endif |
60 | #define EXT2_DFL_CHECKINTERVAL (86400L * 180L) |
61 | |
62 | /* |
63 | * Calculate the number of GDT blocks to reserve for online filesystem growth. |
64 | * The absolute maximum number of GDT blocks we can reserve is determined by |
65 | * the number of block pointers that can fit into a single block. |
66 | */ |
67 | static int calc_reserved_gdt_blocks(ext2_filsys fs) |
68 | { |
69 | struct ext2_super_block *sb = fs->super; |
70 | unsigned long bpg = sb->s_blocks_per_group; |
71 | unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc); |
72 | unsigned long max_blocks = 0xffffffff; |
73 | unsigned long rsv_groups; |
74 | int rsv_gdb; |
75 | |
76 | /* We set it at 1024x the current filesystem size, or |
77 | * the upper block count limit (2^32), whichever is lower. |
78 | */ |
79 | if (sb->s_blocks_count < max_blocks / 1024) |
80 | max_blocks = sb->s_blocks_count * 1024; |
81 | rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg; |
82 | rsv_gdb = (rsv_groups + gdpb - 1) / gdpb - fs->desc_blocks; |
83 | if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb)) |
84 | rsv_gdb = EXT2_ADDR_PER_BLOCK(sb); |
85 | #ifdef RES_GDT_DEBUG |
86 | printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n", |
87 | max_blocks, rsv_groups, rsv_gdb); |
88 | #endif |
89 | |
90 | return rsv_gdb; |
91 | } |
92 | |
93 | errcode_t ext2fs_initialize(const char *name, int flags, |
94 | struct ext2_super_block *param, |
95 | io_manager manager, ext2_filsys *ret_fs) |
96 | { |
97 | ext2_filsys fs; |
98 | errcode_t retval; |
99 | struct ext2_super_block *super; |
100 | int frags_per_block; |
101 | unsigned int rem; |
102 | unsigned int overhead = 0; |
103 | blk_t group_block; |
104 | unsigned int ipg; |
105 | dgrp_t i; |
106 | blk_t numblocks; |
107 | int rsv_gdt; |
108 | char *buf; |
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 | retval = manager->open(name, IO_FLAG_RW, &fs->io); |
125 | if (retval) |
126 | goto cleanup; |
127 | fs->image_io = fs->io; |
128 | fs->io->app_data = fs; |
129 | retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); |
130 | if (retval) |
131 | goto cleanup; |
132 | |
133 | strcpy(fs->device_name, name); |
134 | retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); |
135 | if (retval) |
136 | goto cleanup; |
137 | fs->super = super; |
138 | |
139 | memset(super, 0, SUPERBLOCK_SIZE); |
140 | |
141 | #define set_field(field, default) (super->field = param->field ? \ |
142 | param->field : (default)) |
143 | |
144 | super->s_magic = EXT2_SUPER_MAGIC; |
145 | super->s_state = EXT2_VALID_FS; |
146 | |
147 | set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ |
148 | set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ |
149 | set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); |
150 | set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); |
151 | set_field(s_errors, EXT2_ERRORS_DEFAULT); |
152 | set_field(s_feature_compat, 0); |
153 | set_field(s_feature_incompat, 0); |
154 | set_field(s_feature_ro_compat, 0); |
155 | set_field(s_first_meta_bg, 0); |
156 | if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { |
157 | retval = EXT2_ET_UNSUPP_FEATURE; |
158 | goto cleanup; |
159 | } |
160 | if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) { |
161 | retval = EXT2_ET_RO_UNSUPP_FEATURE; |
162 | goto cleanup; |
163 | } |
164 | |
165 | set_field(s_rev_level, EXT2_GOOD_OLD_REV); |
166 | if (super->s_rev_level >= EXT2_DYNAMIC_REV) { |
167 | set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); |
168 | set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); |
169 | } |
170 | |
171 | set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); |
172 | super->s_mkfs_time = super->s_lastcheck = time(NULL); |
173 | |
174 | super->s_creator_os = CREATOR_OS; |
175 | |
176 | fs->blocksize = EXT2_BLOCK_SIZE(super); |
177 | fs->fragsize = EXT2_FRAG_SIZE(super); |
178 | frags_per_block = fs->blocksize / fs->fragsize; |
179 | |
180 | /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ |
181 | set_field(s_blocks_per_group, fs->blocksize * 8); |
182 | if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) |
183 | super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); |
184 | super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; |
185 | |
186 | super->s_blocks_count = param->s_blocks_count; |
187 | super->s_r_blocks_count = param->s_r_blocks_count; |
188 | if (super->s_r_blocks_count >= param->s_blocks_count) { |
189 | retval = EXT2_ET_INVALID_ARGUMENT; |
190 | goto cleanup; |
191 | } |
192 | |
193 | /* |
194 | * If we're creating an external journal device, we don't need |
195 | * to bother with the rest. |
196 | */ |
197 | if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { |
198 | fs->group_desc_count = 0; |
199 | ext2fs_mark_super_dirty(fs); |
200 | *ret_fs = fs; |
201 | return 0; |
202 | } |
203 | |
204 | retry: |
205 | fs->group_desc_count = (super->s_blocks_count - |
206 | super->s_first_data_block + |
207 | EXT2_BLOCKS_PER_GROUP(super) - 1) |
208 | / EXT2_BLOCKS_PER_GROUP(super); |
209 | if (fs->group_desc_count == 0) { |
210 | retval = EXT2_ET_TOOSMALL; |
211 | goto cleanup; |
212 | } |
213 | fs->desc_blocks = (fs->group_desc_count + |
214 | EXT2_DESC_PER_BLOCK(super) - 1) |
215 | / EXT2_DESC_PER_BLOCK(super); |
216 | |
217 | i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; |
218 | set_field(s_inodes_count, super->s_blocks_count / i); |
219 | |
220 | /* |
221 | * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so |
222 | * that we have enough inodes for the filesystem(!) |
223 | */ |
224 | if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) |
225 | super->s_inodes_count = EXT2_FIRST_INODE(super)+1; |
226 | |
227 | /* |
228 | * There should be at least as many inodes as the user |
229 | * requested. Figure out how many inodes per group that |
230 | * should be. But make sure that we don't allocate more than |
231 | * one bitmap's worth of inodes each group. |
232 | */ |
233 | ipg = (super->s_inodes_count + fs->group_desc_count - 1) / |
234 | fs->group_desc_count; |
235 | if (ipg > fs->blocksize * 8) { |
236 | if (super->s_blocks_per_group >= 256) { |
237 | /* Try again with slightly different parameters */ |
238 | super->s_blocks_per_group -= 8; |
239 | super->s_blocks_count = param->s_blocks_count; |
240 | super->s_frags_per_group = super->s_blocks_per_group * |
241 | frags_per_block; |
242 | goto retry; |
243 | } else |
244 | return EXT2_ET_TOO_MANY_INODES; |
245 | } |
246 | |
247 | if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) |
248 | ipg = EXT2_MAX_INODES_PER_GROUP(super); |
249 | |
250 | super->s_inodes_per_group = ipg; |
251 | if (super->s_inodes_count > ipg * fs->group_desc_count) |
252 | super->s_inodes_count = ipg * fs->group_desc_count; |
253 | |
254 | /* |
255 | * Make sure the number of inodes per group completely fills |
256 | * the inode table blocks in the descriptor. If not, add some |
257 | * additional inodes/group. Waste not, want not... |
258 | */ |
259 | fs->inode_blocks_per_group = (((super->s_inodes_per_group * |
260 | EXT2_INODE_SIZE(super)) + |
261 | EXT2_BLOCK_SIZE(super) - 1) / |
262 | EXT2_BLOCK_SIZE(super)); |
263 | super->s_inodes_per_group = ((fs->inode_blocks_per_group * |
264 | EXT2_BLOCK_SIZE(super)) / |
265 | EXT2_INODE_SIZE(super)); |
266 | /* |
267 | * Finally, make sure the number of inodes per group is a |
268 | * multiple of 8. This is needed to simplify the bitmap |
269 | * splicing code. |
270 | */ |
271 | super->s_inodes_per_group &= ~7; |
272 | fs->inode_blocks_per_group = (((super->s_inodes_per_group * |
273 | EXT2_INODE_SIZE(super)) + |
274 | EXT2_BLOCK_SIZE(super) - 1) / |
275 | EXT2_BLOCK_SIZE(super)); |
276 | |
277 | /* |
278 | * adjust inode count to reflect the adjusted inodes_per_group |
279 | */ |
280 | super->s_inodes_count = super->s_inodes_per_group * |
281 | fs->group_desc_count; |
282 | super->s_free_inodes_count = super->s_inodes_count; |
283 | |
284 | /* |
285 | * check the number of reserved group descriptor table blocks |
286 | */ |
287 | if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INO) |
288 | rsv_gdt = calc_reserved_gdt_blocks(fs); |
289 | else |
290 | rsv_gdt = 0; |
291 | set_field(s_reserved_gdt_blocks, rsv_gdt); |
292 | if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) { |
293 | retval = EXT2_ET_RES_GDT_BLOCKS; |
294 | goto cleanup; |
295 | } |
296 | |
297 | /* |
298 | * Overhead is the number of bookkeeping blocks per group. It |
299 | * includes the superblock backup, the group descriptor |
300 | * backups, the inode bitmap, the block bitmap, and the inode |
301 | * table. |
302 | */ |
303 | |
304 | overhead = (int) (2 + fs->inode_blocks_per_group); |
305 | |
306 | if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1)) |
307 | overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks; |
308 | |
309 | /* This can only happen if the user requested too many inodes */ |
310 | if (overhead > super->s_blocks_per_group) |
311 | return EXT2_ET_TOO_MANY_INODES; |
312 | |
313 | /* |
314 | * See if the last group is big enough to support the |
315 | * necessary data structures. If not, we need to get rid of |
316 | * it. |
317 | */ |
318 | rem = ((super->s_blocks_count - super->s_first_data_block) % |
319 | super->s_blocks_per_group); |
320 | if ((fs->group_desc_count == 1) && rem && (rem < overhead)) |
321 | return EXT2_ET_TOOSMALL; |
322 | if (rem && (rem < overhead+50)) { |
323 | super->s_blocks_count -= rem; |
324 | goto retry; |
325 | } |
326 | |
327 | /* |
328 | * At this point we know how big the filesystem will be. So |
329 | * we can do any and all allocations that depend on the block |
330 | * count. |
331 | */ |
332 | |
333 | retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); |
334 | if (retval) |
335 | goto cleanup; |
336 | |
337 | sprintf(buf, "block bitmap for %s", fs->device_name); |
338 | retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); |
339 | if (retval) |
340 | goto cleanup; |
341 | |
342 | sprintf(buf, "inode bitmap for %s", fs->device_name); |
343 | retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); |
344 | if (retval) |
345 | goto cleanup; |
346 | |
347 | ext2fs_free_mem(&buf); |
348 | |
349 | retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, |
350 | &fs->group_desc); |
351 | if (retval) |
352 | goto cleanup; |
353 | |
354 | memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); |
355 | |
356 | /* |
357 | * Reserve the superblock and group descriptors for each |
358 | * group, and fill in the correct group statistics for group. |
359 | * Note that although the block bitmap, inode bitmap, and |
360 | * inode table have not been allocated (and in fact won't be |
361 | * by this routine), they are accounted for nevertheless. |
362 | */ |
363 | group_block = super->s_first_data_block; |
364 | super->s_free_blocks_count = 0; |
365 | for (i = 0; i < fs->group_desc_count; i++) { |
366 | numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); |
367 | |
368 | super->s_free_blocks_count += numblocks; |
369 | fs->group_desc[i].bg_free_blocks_count = numblocks; |
370 | fs->group_desc[i].bg_free_inodes_count = |
371 | fs->super->s_inodes_per_group; |
372 | fs->group_desc[i].bg_used_dirs_count = 0; |
373 | |
374 | group_block += super->s_blocks_per_group; |
375 | } |
376 | |
377 | ext2fs_mark_super_dirty(fs); |
378 | ext2fs_mark_bb_dirty(fs); |
379 | ext2fs_mark_ib_dirty(fs); |
380 | |
381 | io_channel_set_blksize(fs->io, fs->blocksize); |
382 | |
383 | *ret_fs = fs; |
384 | return 0; |
385 | cleanup: |
386 | ext2fs_free(fs); |
387 | return retval; |
388 | } |
389 |