1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * This file is part of UBIFS.
4 *
5 * Copyright (C) 2006-2008 Nokia Corporation.
6 *
7 * Authors: Artem Bityutskiy (Битюцкий Артём)
8 * Adrian Hunter
9 */
10
11 /* This file implements reading and writing the master node */
12
13 #include "ubifs.h"
14 #ifdef __UBOOT__
15 #include <linux/compat.h>
16 #include <linux/err.h>
17 #include <ubi_uboot.h>
18 #endif
19
20 /**
21 * scan_for_master - search the valid master node.
22 * @c: UBIFS file-system description object
23 *
24 * This function scans the master node LEBs and search for the latest master
25 * node. Returns zero in case of success, %-EUCLEAN if there master area is
26 * corrupted and requires recovery, and a negative error code in case of
27 * failure.
28 */
scan_for_master(struct ubifs_info * c)29 static int scan_for_master(struct ubifs_info *c)
30 {
31 struct ubifs_scan_leb *sleb;
32 struct ubifs_scan_node *snod;
33 int lnum, offs = 0, nodes_cnt;
34
35 lnum = UBIFS_MST_LNUM;
36
37 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
38 if (IS_ERR(sleb))
39 return PTR_ERR(sleb);
40 nodes_cnt = sleb->nodes_cnt;
41 if (nodes_cnt > 0) {
42 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
43 list);
44 if (snod->type != UBIFS_MST_NODE)
45 goto out_dump;
46 memcpy(c->mst_node, snod->node, snod->len);
47 offs = snod->offs;
48 }
49 ubifs_scan_destroy(sleb);
50
51 lnum += 1;
52
53 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
54 if (IS_ERR(sleb))
55 return PTR_ERR(sleb);
56 if (sleb->nodes_cnt != nodes_cnt)
57 goto out;
58 if (!sleb->nodes_cnt)
59 goto out;
60 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list);
61 if (snod->type != UBIFS_MST_NODE)
62 goto out_dump;
63 if (snod->offs != offs)
64 goto out;
65 if (memcmp((void *)c->mst_node + UBIFS_CH_SZ,
66 (void *)snod->node + UBIFS_CH_SZ,
67 UBIFS_MST_NODE_SZ - UBIFS_CH_SZ))
68 goto out;
69 c->mst_offs = offs;
70 ubifs_scan_destroy(sleb);
71 return 0;
72
73 out:
74 ubifs_scan_destroy(sleb);
75 return -EUCLEAN;
76
77 out_dump:
78 ubifs_err(c, "unexpected node type %d master LEB %d:%d",
79 snod->type, lnum, snod->offs);
80 ubifs_scan_destroy(sleb);
81 return -EINVAL;
82 }
83
84 /**
85 * validate_master - validate master node.
86 * @c: UBIFS file-system description object
87 *
88 * This function validates data which was read from master node. Returns zero
89 * if the data is all right and %-EINVAL if not.
90 */
validate_master(const struct ubifs_info * c)91 static int validate_master(const struct ubifs_info *c)
92 {
93 long long main_sz;
94 int err;
95
96 if (c->max_sqnum >= SQNUM_WATERMARK) {
97 err = 1;
98 goto out;
99 }
100
101 if (c->cmt_no >= c->max_sqnum) {
102 err = 2;
103 goto out;
104 }
105
106 if (c->highest_inum >= INUM_WATERMARK) {
107 err = 3;
108 goto out;
109 }
110
111 if (c->lhead_lnum < UBIFS_LOG_LNUM ||
112 c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs ||
113 c->lhead_offs < 0 || c->lhead_offs >= c->leb_size ||
114 c->lhead_offs & (c->min_io_size - 1)) {
115 err = 4;
116 goto out;
117 }
118
119 if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first ||
120 c->zroot.offs >= c->leb_size || c->zroot.offs & 7) {
121 err = 5;
122 goto out;
123 }
124
125 if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len ||
126 c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) {
127 err = 6;
128 goto out;
129 }
130
131 if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) {
132 err = 7;
133 goto out;
134 }
135
136 if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first ||
137 c->ihead_offs % c->min_io_size || c->ihead_offs < 0 ||
138 c->ihead_offs > c->leb_size || c->ihead_offs & 7) {
139 err = 8;
140 goto out;
141 }
142
143 main_sz = (long long)c->main_lebs * c->leb_size;
144 if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) {
145 err = 9;
146 goto out;
147 }
148
149 if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last ||
150 c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) {
151 err = 10;
152 goto out;
153 }
154
155 if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last ||
156 c->nhead_offs < 0 || c->nhead_offs % c->min_io_size ||
157 c->nhead_offs > c->leb_size) {
158 err = 11;
159 goto out;
160 }
161
162 if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last ||
163 c->ltab_offs < 0 ||
164 c->ltab_offs + c->ltab_sz > c->leb_size) {
165 err = 12;
166 goto out;
167 }
168
169 if (c->big_lpt && (c->lsave_lnum < c->lpt_first ||
170 c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 ||
171 c->lsave_offs + c->lsave_sz > c->leb_size)) {
172 err = 13;
173 goto out;
174 }
175
176 if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) {
177 err = 14;
178 goto out;
179 }
180
181 if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) {
182 err = 15;
183 goto out;
184 }
185
186 if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) {
187 err = 16;
188 goto out;
189 }
190
191 if (c->lst.total_free < 0 || c->lst.total_free > main_sz ||
192 c->lst.total_free & 7) {
193 err = 17;
194 goto out;
195 }
196
197 if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) {
198 err = 18;
199 goto out;
200 }
201
202 if (c->lst.total_used < 0 || (c->lst.total_used & 7)) {
203 err = 19;
204 goto out;
205 }
206
207 if (c->lst.total_free + c->lst.total_dirty +
208 c->lst.total_used > main_sz) {
209 err = 20;
210 goto out;
211 }
212
213 if (c->lst.total_dead + c->lst.total_dark +
214 c->lst.total_used + c->bi.old_idx_sz > main_sz) {
215 err = 21;
216 goto out;
217 }
218
219 if (c->lst.total_dead < 0 ||
220 c->lst.total_dead > c->lst.total_free + c->lst.total_dirty ||
221 c->lst.total_dead & 7) {
222 err = 22;
223 goto out;
224 }
225
226 if (c->lst.total_dark < 0 ||
227 c->lst.total_dark > c->lst.total_free + c->lst.total_dirty ||
228 c->lst.total_dark & 7) {
229 err = 23;
230 goto out;
231 }
232
233 return 0;
234
235 out:
236 ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err);
237 ubifs_dump_node(c, c->mst_node);
238 return -EINVAL;
239 }
240
241 /**
242 * ubifs_read_master - read master node.
243 * @c: UBIFS file-system description object
244 *
245 * This function finds and reads the master node during file-system mount. If
246 * the flash is empty, it creates default master node as well. Returns zero in
247 * case of success and a negative error code in case of failure.
248 */
ubifs_read_master(struct ubifs_info * c)249 int ubifs_read_master(struct ubifs_info *c)
250 {
251 int err, old_leb_cnt;
252
253 c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL);
254 if (!c->mst_node)
255 return -ENOMEM;
256
257 err = scan_for_master(c);
258 if (err) {
259 if (err == -EUCLEAN)
260 err = ubifs_recover_master_node(c);
261 if (err)
262 /*
263 * Note, we do not free 'c->mst_node' here because the
264 * unmount routine will take care of this.
265 */
266 return err;
267 }
268
269 /* Make sure that the recovery flag is clear */
270 c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY);
271
272 c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum);
273 c->highest_inum = le64_to_cpu(c->mst_node->highest_inum);
274 c->cmt_no = le64_to_cpu(c->mst_node->cmt_no);
275 c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum);
276 c->zroot.offs = le32_to_cpu(c->mst_node->root_offs);
277 c->zroot.len = le32_to_cpu(c->mst_node->root_len);
278 c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum);
279 c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum);
280 c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum);
281 c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs);
282 c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size);
283 c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum);
284 c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs);
285 c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum);
286 c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs);
287 c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum);
288 c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs);
289 c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum);
290 c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs);
291 c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum);
292 c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs);
293 c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs);
294 old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt);
295 c->lst.total_free = le64_to_cpu(c->mst_node->total_free);
296 c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty);
297 c->lst.total_used = le64_to_cpu(c->mst_node->total_used);
298 c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead);
299 c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark);
300
301 c->calc_idx_sz = c->bi.old_idx_sz;
302
303 if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS))
304 c->no_orphs = 1;
305
306 if (old_leb_cnt != c->leb_cnt) {
307 /* The file system has been resized */
308 int growth = c->leb_cnt - old_leb_cnt;
309
310 if (c->leb_cnt < old_leb_cnt ||
311 c->leb_cnt < UBIFS_MIN_LEB_CNT) {
312 ubifs_err(c, "bad leb_cnt on master node");
313 ubifs_dump_node(c, c->mst_node);
314 return -EINVAL;
315 }
316
317 dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs",
318 old_leb_cnt, c->leb_cnt);
319 c->lst.empty_lebs += growth;
320 c->lst.total_free += growth * (long long)c->leb_size;
321 c->lst.total_dark += growth * (long long)c->dark_wm;
322
323 /*
324 * Reflect changes back onto the master node. N.B. the master
325 * node gets written immediately whenever mounting (or
326 * remounting) in read-write mode, so we do not need to write it
327 * here.
328 */
329 c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt);
330 c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs);
331 c->mst_node->total_free = cpu_to_le64(c->lst.total_free);
332 c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark);
333 }
334
335 err = validate_master(c);
336 if (err)
337 return err;
338
339 #ifndef __UBOOT__
340 err = dbg_old_index_check_init(c, &c->zroot);
341 #endif
342
343 return err;
344 }
345
346 #ifndef __UBOOT__
347 /**
348 * ubifs_write_master - write master node.
349 * @c: UBIFS file-system description object
350 *
351 * This function writes the master node. Returns zero in case of success and a
352 * negative error code in case of failure. The master node is written twice to
353 * enable recovery.
354 */
ubifs_write_master(struct ubifs_info * c)355 int ubifs_write_master(struct ubifs_info *c)
356 {
357 int err, lnum, offs, len;
358
359 ubifs_assert(!c->ro_media && !c->ro_mount);
360 if (c->ro_error)
361 return -EROFS;
362
363 lnum = UBIFS_MST_LNUM;
364 offs = c->mst_offs + c->mst_node_alsz;
365 len = UBIFS_MST_NODE_SZ;
366
367 if (offs + UBIFS_MST_NODE_SZ > c->leb_size) {
368 err = ubifs_leb_unmap(c, lnum);
369 if (err)
370 return err;
371 offs = 0;
372 }
373
374 c->mst_offs = offs;
375 c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
376
377 err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
378 if (err)
379 return err;
380
381 lnum += 1;
382
383 if (offs == 0) {
384 err = ubifs_leb_unmap(c, lnum);
385 if (err)
386 return err;
387 }
388 err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
389
390 return err;
391 }
392 #endif
393