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 /* This file implements reading and writing the master node */
24
25 #include "ubifs.h"
26
27 /**
28 * scan_for_master - search the valid master node.
29 * @c: UBIFS file-system description object
30 *
31 * This function scans the master node LEBs and search for the latest master
32 * node. Returns zero in case of success, %-EUCLEAN if there master area is
33 * corrupted and requires recovery, and a negative error code in case of
34 * failure.
35 */
scan_for_master(struct ubifs_info * c)36 static int scan_for_master(struct ubifs_info *c)
37 {
38 struct ubifs_scan_leb *sleb;
39 struct ubifs_scan_node *snod;
40 int lnum, offs = 0, nodes_cnt;
41
42 lnum = UBIFS_MST_LNUM;
43
44 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
45 if (IS_ERR(sleb))
46 return PTR_ERR(sleb);
47 nodes_cnt = sleb->nodes_cnt;
48 if (nodes_cnt > 0) {
49 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
50 list);
51 if (snod->type != UBIFS_MST_NODE)
52 goto out_dump;
53 memcpy(c->mst_node, snod->node, snod->len);
54 offs = snod->offs;
55 }
56 ubifs_scan_destroy(sleb);
57
58 lnum += 1;
59
60 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
61 if (IS_ERR(sleb))
62 return PTR_ERR(sleb);
63 if (sleb->nodes_cnt != nodes_cnt)
64 goto out;
65 if (!sleb->nodes_cnt)
66 goto out;
67 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list);
68 if (snod->type != UBIFS_MST_NODE)
69 goto out_dump;
70 if (snod->offs != offs)
71 goto out;
72 if (memcmp((void *)c->mst_node + UBIFS_CH_SZ,
73 (void *)snod->node + UBIFS_CH_SZ,
74 UBIFS_MST_NODE_SZ - UBIFS_CH_SZ))
75 goto out;
76 c->mst_offs = offs;
77 ubifs_scan_destroy(sleb);
78 return 0;
79
80 out:
81 ubifs_scan_destroy(sleb);
82 return -EUCLEAN;
83
84 out_dump:
85 ubifs_err(c, "unexpected node type %d master LEB %d:%d",
86 snod->type, lnum, snod->offs);
87 ubifs_scan_destroy(sleb);
88 return -EINVAL;
89 }
90
91 /**
92 * validate_master - validate master node.
93 * @c: UBIFS file-system description object
94 *
95 * This function validates data which was read from master node. Returns zero
96 * if the data is all right and %-EINVAL if not.
97 */
validate_master(const struct ubifs_info * c)98 static int validate_master(const struct ubifs_info *c)
99 {
100 long long main_sz;
101 int err;
102
103 if (c->max_sqnum >= SQNUM_WATERMARK) {
104 err = 1;
105 goto out;
106 }
107
108 if (c->cmt_no >= c->max_sqnum) {
109 err = 2;
110 goto out;
111 }
112
113 if (c->highest_inum >= INUM_WATERMARK) {
114 err = 3;
115 goto out;
116 }
117
118 if (c->lhead_lnum < UBIFS_LOG_LNUM ||
119 c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs ||
120 c->lhead_offs < 0 || c->lhead_offs >= c->leb_size ||
121 c->lhead_offs & (c->min_io_size - 1)) {
122 err = 4;
123 goto out;
124 }
125
126 if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first ||
127 c->zroot.offs >= c->leb_size || c->zroot.offs & 7) {
128 err = 5;
129 goto out;
130 }
131
132 if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len ||
133 c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) {
134 err = 6;
135 goto out;
136 }
137
138 if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) {
139 err = 7;
140 goto out;
141 }
142
143 if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first ||
144 c->ihead_offs % c->min_io_size || c->ihead_offs < 0 ||
145 c->ihead_offs > c->leb_size || c->ihead_offs & 7) {
146 err = 8;
147 goto out;
148 }
149
150 main_sz = (long long)c->main_lebs * c->leb_size;
151 if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) {
152 err = 9;
153 goto out;
154 }
155
156 if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last ||
157 c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) {
158 err = 10;
159 goto out;
160 }
161
162 if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last ||
163 c->nhead_offs < 0 || c->nhead_offs % c->min_io_size ||
164 c->nhead_offs > c->leb_size) {
165 err = 11;
166 goto out;
167 }
168
169 if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last ||
170 c->ltab_offs < 0 ||
171 c->ltab_offs + c->ltab_sz > c->leb_size) {
172 err = 12;
173 goto out;
174 }
175
176 if (c->big_lpt && (c->lsave_lnum < c->lpt_first ||
177 c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 ||
178 c->lsave_offs + c->lsave_sz > c->leb_size)) {
179 err = 13;
180 goto out;
181 }
182
183 if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) {
184 err = 14;
185 goto out;
186 }
187
188 if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) {
189 err = 15;
190 goto out;
191 }
192
193 if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) {
194 err = 16;
195 goto out;
196 }
197
198 if (c->lst.total_free < 0 || c->lst.total_free > main_sz ||
199 c->lst.total_free & 7) {
200 err = 17;
201 goto out;
202 }
203
204 if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) {
205 err = 18;
206 goto out;
207 }
208
209 if (c->lst.total_used < 0 || (c->lst.total_used & 7)) {
210 err = 19;
211 goto out;
212 }
213
214 if (c->lst.total_free + c->lst.total_dirty +
215 c->lst.total_used > main_sz) {
216 err = 20;
217 goto out;
218 }
219
220 if (c->lst.total_dead + c->lst.total_dark +
221 c->lst.total_used + c->bi.old_idx_sz > main_sz) {
222 err = 21;
223 goto out;
224 }
225
226 if (c->lst.total_dead < 0 ||
227 c->lst.total_dead > c->lst.total_free + c->lst.total_dirty ||
228 c->lst.total_dead & 7) {
229 err = 22;
230 goto out;
231 }
232
233 if (c->lst.total_dark < 0 ||
234 c->lst.total_dark > c->lst.total_free + c->lst.total_dirty ||
235 c->lst.total_dark & 7) {
236 err = 23;
237 goto out;
238 }
239
240 return 0;
241
242 out:
243 ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err);
244 ubifs_dump_node(c, c->mst_node);
245 return -EINVAL;
246 }
247
248 /**
249 * ubifs_read_master - read master node.
250 * @c: UBIFS file-system description object
251 *
252 * This function finds and reads the master node during file-system mount. If
253 * the flash is empty, it creates default master node as well. Returns zero in
254 * case of success and a negative error code in case of failure.
255 */
ubifs_read_master(struct ubifs_info * c)256 int ubifs_read_master(struct ubifs_info *c)
257 {
258 int err, old_leb_cnt;
259
260 c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL);
261 if (!c->mst_node)
262 return -ENOMEM;
263
264 err = scan_for_master(c);
265 if (err) {
266 if (err == -EUCLEAN)
267 err = ubifs_recover_master_node(c);
268 if (err)
269 /*
270 * Note, we do not free 'c->mst_node' here because the
271 * unmount routine will take care of this.
272 */
273 return err;
274 }
275
276 /* Make sure that the recovery flag is clear */
277 c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY);
278
279 c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum);
280 c->highest_inum = le64_to_cpu(c->mst_node->highest_inum);
281 c->cmt_no = le64_to_cpu(c->mst_node->cmt_no);
282 c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum);
283 c->zroot.offs = le32_to_cpu(c->mst_node->root_offs);
284 c->zroot.len = le32_to_cpu(c->mst_node->root_len);
285 c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum);
286 c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum);
287 c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum);
288 c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs);
289 c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size);
290 c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum);
291 c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs);
292 c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum);
293 c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs);
294 c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum);
295 c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs);
296 c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum);
297 c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs);
298 c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum);
299 c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs);
300 c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs);
301 old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt);
302 c->lst.total_free = le64_to_cpu(c->mst_node->total_free);
303 c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty);
304 c->lst.total_used = le64_to_cpu(c->mst_node->total_used);
305 c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead);
306 c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark);
307
308 c->calc_idx_sz = c->bi.old_idx_sz;
309
310 if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS))
311 c->no_orphs = 1;
312
313 if (old_leb_cnt != c->leb_cnt) {
314 /* The file system has been resized */
315 int growth = c->leb_cnt - old_leb_cnt;
316
317 if (c->leb_cnt < old_leb_cnt ||
318 c->leb_cnt < UBIFS_MIN_LEB_CNT) {
319 ubifs_err(c, "bad leb_cnt on master node");
320 ubifs_dump_node(c, c->mst_node);
321 return -EINVAL;
322 }
323
324 dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs",
325 old_leb_cnt, c->leb_cnt);
326 c->lst.empty_lebs += growth;
327 c->lst.total_free += growth * (long long)c->leb_size;
328 c->lst.total_dark += growth * (long long)c->dark_wm;
329
330 /*
331 * Reflect changes back onto the master node. N.B. the master
332 * node gets written immediately whenever mounting (or
333 * remounting) in read-write mode, so we do not need to write it
334 * here.
335 */
336 c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt);
337 c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs);
338 c->mst_node->total_free = cpu_to_le64(c->lst.total_free);
339 c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark);
340 }
341
342 err = validate_master(c);
343 if (err)
344 return err;
345
346 err = dbg_old_index_check_init(c, &c->zroot);
347
348 return err;
349 }
350
351 /**
352 * ubifs_write_master - write master node.
353 * @c: UBIFS file-system description object
354 *
355 * This function writes the master node. Returns zero in case of success and a
356 * negative error code in case of failure. The master node is written twice to
357 * enable recovery.
358 */
ubifs_write_master(struct ubifs_info * c)359 int ubifs_write_master(struct ubifs_info *c)
360 {
361 int err, lnum, offs, len;
362
363 ubifs_assert(c, !c->ro_media && !c->ro_mount);
364 if (c->ro_error)
365 return -EROFS;
366
367 lnum = UBIFS_MST_LNUM;
368 offs = c->mst_offs + c->mst_node_alsz;
369 len = UBIFS_MST_NODE_SZ;
370
371 if (offs + UBIFS_MST_NODE_SZ > c->leb_size) {
372 err = ubifs_leb_unmap(c, lnum);
373 if (err)
374 return err;
375 offs = 0;
376 }
377
378 c->mst_offs = offs;
379 c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
380
381 err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
382 if (err)
383 return err;
384
385 lnum += 1;
386
387 if (offs == 0) {
388 err = ubifs_leb_unmap(c, lnum);
389 if (err)
390 return err;
391 }
392 err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
393
394 return err;
395 }
396