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9eefe2a2 SR |
1 | /* |
2 | * This file is part of UBIFS. | |
3 | * | |
4 | * Copyright (C) 2006-2008 Nokia Corporation. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License version 2 as published by | |
8 | * the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along with | |
16 | * this program; if not, write to the Free Software Foundation, Inc., 51 | |
17 | * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | * | |
19 | * Authors: Artem Bityutskiy (Битюцкий Артём) | |
20 | * Adrian Hunter | |
21 | */ | |
22 | ||
23 | /* | |
24 | * This file implements UBIFS superblock. The superblock is stored at the first | |
25 | * LEB of the volume and is never changed by UBIFS. Only user-space tools may | |
26 | * change it. The superblock node mostly contains geometry information. | |
27 | */ | |
28 | ||
29 | #include "ubifs.h" | |
30 | ||
31 | /* | |
32 | * Default journal size in logical eraseblocks as a percent of total | |
33 | * flash size. | |
34 | */ | |
35 | #define DEFAULT_JNL_PERCENT 5 | |
36 | ||
37 | /* Default maximum journal size in bytes */ | |
38 | #define DEFAULT_MAX_JNL (32*1024*1024) | |
39 | ||
40 | /* Default indexing tree fanout */ | |
41 | #define DEFAULT_FANOUT 8 | |
42 | ||
43 | /* Default number of data journal heads */ | |
44 | #define DEFAULT_JHEADS_CNT 1 | |
45 | ||
46 | /* Default positions of different LEBs in the main area */ | |
47 | #define DEFAULT_IDX_LEB 0 | |
48 | #define DEFAULT_DATA_LEB 1 | |
49 | #define DEFAULT_GC_LEB 2 | |
50 | ||
51 | /* Default number of LEB numbers in LPT's save table */ | |
52 | #define DEFAULT_LSAVE_CNT 256 | |
53 | ||
54 | /* Default reserved pool size as a percent of maximum free space */ | |
55 | #define DEFAULT_RP_PERCENT 5 | |
56 | ||
57 | /* The default maximum size of reserved pool in bytes */ | |
58 | #define DEFAULT_MAX_RP_SIZE (5*1024*1024) | |
59 | ||
60 | /* Default time granularity in nanoseconds */ | |
61 | #define DEFAULT_TIME_GRAN 1000000000 | |
62 | ||
63 | /** | |
64 | * validate_sb - validate superblock node. | |
65 | * @c: UBIFS file-system description object | |
66 | * @sup: superblock node | |
67 | * | |
68 | * This function validates superblock node @sup. Since most of data was read | |
69 | * from the superblock and stored in @c, the function validates fields in @c | |
70 | * instead. Returns zero in case of success and %-EINVAL in case of validation | |
71 | * failure. | |
72 | */ | |
73 | static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup) | |
74 | { | |
75 | long long max_bytes; | |
76 | int err = 1, min_leb_cnt; | |
77 | ||
78 | if (!c->key_hash) { | |
79 | err = 2; | |
80 | goto failed; | |
81 | } | |
82 | ||
83 | if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) { | |
84 | err = 3; | |
85 | goto failed; | |
86 | } | |
87 | ||
88 | if (le32_to_cpu(sup->min_io_size) != c->min_io_size) { | |
89 | ubifs_err("min. I/O unit mismatch: %d in superblock, %d real", | |
90 | le32_to_cpu(sup->min_io_size), c->min_io_size); | |
91 | goto failed; | |
92 | } | |
93 | ||
94 | if (le32_to_cpu(sup->leb_size) != c->leb_size) { | |
95 | ubifs_err("LEB size mismatch: %d in superblock, %d real", | |
96 | le32_to_cpu(sup->leb_size), c->leb_size); | |
97 | goto failed; | |
98 | } | |
99 | ||
100 | if (c->log_lebs < UBIFS_MIN_LOG_LEBS || | |
101 | c->lpt_lebs < UBIFS_MIN_LPT_LEBS || | |
102 | c->orph_lebs < UBIFS_MIN_ORPH_LEBS || | |
103 | c->main_lebs < UBIFS_MIN_MAIN_LEBS) { | |
104 | err = 4; | |
105 | goto failed; | |
106 | } | |
107 | ||
108 | /* | |
109 | * Calculate minimum allowed amount of main area LEBs. This is very | |
110 | * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we | |
111 | * have just read from the superblock. | |
112 | */ | |
113 | min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs; | |
114 | min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6; | |
115 | ||
116 | if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) { | |
117 | ubifs_err("bad LEB count: %d in superblock, %d on UBI volume, " | |
118 | "%d minimum required", c->leb_cnt, c->vi.size, | |
119 | min_leb_cnt); | |
120 | goto failed; | |
121 | } | |
122 | ||
123 | if (c->max_leb_cnt < c->leb_cnt) { | |
124 | ubifs_err("max. LEB count %d less than LEB count %d", | |
125 | c->max_leb_cnt, c->leb_cnt); | |
126 | goto failed; | |
127 | } | |
128 | ||
129 | if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) { | |
130 | err = 7; | |
131 | goto failed; | |
132 | } | |
133 | ||
134 | if (c->max_bud_bytes < (long long)c->leb_size * UBIFS_MIN_BUD_LEBS || | |
135 | c->max_bud_bytes > (long long)c->leb_size * c->main_lebs) { | |
136 | err = 8; | |
137 | goto failed; | |
138 | } | |
139 | ||
140 | if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 || | |
141 | c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) { | |
142 | err = 9; | |
143 | goto failed; | |
144 | } | |
145 | ||
146 | if (c->fanout < UBIFS_MIN_FANOUT || | |
147 | ubifs_idx_node_sz(c, c->fanout) > c->leb_size) { | |
148 | err = 10; | |
149 | goto failed; | |
150 | } | |
151 | ||
152 | if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT && | |
153 | c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - | |
154 | c->log_lebs - c->lpt_lebs - c->orph_lebs)) { | |
155 | err = 11; | |
156 | goto failed; | |
157 | } | |
158 | ||
159 | if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs + | |
160 | c->orph_lebs + c->main_lebs != c->leb_cnt) { | |
161 | err = 12; | |
162 | goto failed; | |
163 | } | |
164 | ||
165 | if (c->default_compr < 0 || c->default_compr >= UBIFS_COMPR_TYPES_CNT) { | |
166 | err = 13; | |
167 | goto failed; | |
168 | } | |
169 | ||
170 | max_bytes = c->main_lebs * (long long)c->leb_size; | |
171 | if (c->rp_size < 0 || max_bytes < c->rp_size) { | |
172 | err = 14; | |
173 | goto failed; | |
174 | } | |
175 | ||
176 | if (le32_to_cpu(sup->time_gran) > 1000000000 || | |
177 | le32_to_cpu(sup->time_gran) < 1) { | |
178 | err = 15; | |
179 | goto failed; | |
180 | } | |
181 | ||
182 | return 0; | |
183 | ||
184 | failed: | |
185 | ubifs_err("bad superblock, error %d", err); | |
186 | dbg_dump_node(c, sup); | |
187 | return -EINVAL; | |
188 | } | |
189 | ||
190 | /** | |
191 | * ubifs_read_sb_node - read superblock node. | |
192 | * @c: UBIFS file-system description object | |
193 | * | |
194 | * This function returns a pointer to the superblock node or a negative error | |
195 | * code. | |
196 | */ | |
197 | struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c) | |
198 | { | |
199 | struct ubifs_sb_node *sup; | |
200 | int err; | |
201 | ||
202 | sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS); | |
203 | if (!sup) | |
204 | return ERR_PTR(-ENOMEM); | |
205 | ||
206 | err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ, | |
207 | UBIFS_SB_LNUM, 0); | |
208 | if (err) { | |
209 | kfree(sup); | |
210 | return ERR_PTR(err); | |
211 | } | |
212 | ||
213 | return sup; | |
214 | } | |
215 | ||
216 | /** | |
217 | * ubifs_read_superblock - read superblock. | |
218 | * @c: UBIFS file-system description object | |
219 | * | |
220 | * This function finds, reads and checks the superblock. If an empty UBI volume | |
221 | * is being mounted, this function creates default superblock. Returns zero in | |
222 | * case of success, and a negative error code in case of failure. | |
223 | */ | |
224 | int ubifs_read_superblock(struct ubifs_info *c) | |
225 | { | |
226 | int err, sup_flags; | |
227 | struct ubifs_sb_node *sup; | |
228 | ||
229 | if (c->empty) { | |
230 | printf("No UBIFS filesystem found!\n"); | |
231 | return -1; | |
232 | } | |
233 | ||
234 | sup = ubifs_read_sb_node(c); | |
235 | if (IS_ERR(sup)) | |
236 | return PTR_ERR(sup); | |
237 | ||
febd7e41 AB |
238 | c->fmt_version = le32_to_cpu(sup->fmt_version); |
239 | c->ro_compat_version = le32_to_cpu(sup->ro_compat_version); | |
240 | ||
9eefe2a2 SR |
241 | /* |
242 | * The software supports all previous versions but not future versions, | |
243 | * due to the unavailability of time-travelling equipment. | |
244 | */ | |
9eefe2a2 | 245 | if (c->fmt_version > UBIFS_FORMAT_VERSION) { |
febd7e41 AB |
246 | struct super_block *sb = c->vfs_sb; |
247 | int mounting_ro = sb->s_flags & MS_RDONLY; | |
248 | ||
249 | ubifs_assert(!c->ro_media || mounting_ro); | |
250 | if (!mounting_ro || | |
251 | c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) { | |
252 | ubifs_err("on-flash format version is w%d/r%d, but " | |
253 | "software only supports up to version " | |
254 | "w%d/r%d", c->fmt_version, | |
255 | c->ro_compat_version, UBIFS_FORMAT_VERSION, | |
256 | UBIFS_RO_COMPAT_VERSION); | |
257 | if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) { | |
258 | ubifs_msg("only R/O mounting is possible"); | |
259 | err = -EROFS; | |
260 | } else | |
261 | err = -EINVAL; | |
262 | goto out; | |
263 | } | |
264 | ||
265 | /* | |
266 | * The FS is mounted R/O, and the media format is | |
267 | * R/O-compatible with the UBIFS implementation, so we can | |
268 | * mount. | |
269 | */ | |
270 | c->rw_incompat = 1; | |
9eefe2a2 SR |
271 | } |
272 | ||
273 | if (c->fmt_version < 3) { | |
274 | ubifs_err("on-flash format version %d is not supported", | |
275 | c->fmt_version); | |
276 | err = -EINVAL; | |
277 | goto out; | |
278 | } | |
279 | ||
280 | switch (sup->key_hash) { | |
281 | case UBIFS_KEY_HASH_R5: | |
282 | c->key_hash = key_r5_hash; | |
283 | c->key_hash_type = UBIFS_KEY_HASH_R5; | |
284 | break; | |
285 | ||
286 | case UBIFS_KEY_HASH_TEST: | |
287 | c->key_hash = key_test_hash; | |
288 | c->key_hash_type = UBIFS_KEY_HASH_TEST; | |
289 | break; | |
290 | }; | |
291 | ||
292 | c->key_fmt = sup->key_fmt; | |
293 | ||
294 | switch (c->key_fmt) { | |
295 | case UBIFS_SIMPLE_KEY_FMT: | |
296 | c->key_len = UBIFS_SK_LEN; | |
297 | break; | |
298 | default: | |
299 | ubifs_err("unsupported key format"); | |
300 | err = -EINVAL; | |
301 | goto out; | |
302 | } | |
303 | ||
304 | c->leb_cnt = le32_to_cpu(sup->leb_cnt); | |
305 | c->max_leb_cnt = le32_to_cpu(sup->max_leb_cnt); | |
306 | c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes); | |
307 | c->log_lebs = le32_to_cpu(sup->log_lebs); | |
308 | c->lpt_lebs = le32_to_cpu(sup->lpt_lebs); | |
309 | c->orph_lebs = le32_to_cpu(sup->orph_lebs); | |
310 | c->jhead_cnt = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT; | |
311 | c->fanout = le32_to_cpu(sup->fanout); | |
312 | c->lsave_cnt = le32_to_cpu(sup->lsave_cnt); | |
313 | c->default_compr = le16_to_cpu(sup->default_compr); | |
314 | c->rp_size = le64_to_cpu(sup->rp_size); | |
315 | c->rp_uid = le32_to_cpu(sup->rp_uid); | |
316 | c->rp_gid = le32_to_cpu(sup->rp_gid); | |
317 | sup_flags = le32_to_cpu(sup->flags); | |
318 | ||
319 | c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran); | |
320 | memcpy(&c->uuid, &sup->uuid, 16); | |
321 | c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT); | |
322 | ||
323 | /* Automatically increase file system size to the maximum size */ | |
324 | c->old_leb_cnt = c->leb_cnt; | |
325 | if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) { | |
326 | c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size); | |
327 | dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs", | |
328 | c->old_leb_cnt, c->leb_cnt); | |
329 | } | |
330 | ||
331 | c->log_bytes = (long long)c->log_lebs * c->leb_size; | |
332 | c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1; | |
333 | c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs; | |
334 | c->lpt_last = c->lpt_first + c->lpt_lebs - 1; | |
335 | c->orph_first = c->lpt_last + 1; | |
336 | c->orph_last = c->orph_first + c->orph_lebs - 1; | |
337 | c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS; | |
338 | c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs; | |
339 | c->main_first = c->leb_cnt - c->main_lebs; | |
340 | c->report_rp_size = ubifs_reported_space(c, c->rp_size); | |
341 | ||
342 | err = validate_sb(c, sup); | |
343 | out: | |
344 | kfree(sup); | |
345 | return err; | |
346 | } |