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2b27bdcc | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1e51764a AB |
2 | /* |
3 | * This file is part of UBIFS. | |
4 | * | |
5 | * Copyright (C) 2006-2008 Nokia Corporation | |
6 | * | |
1e51764a AB |
7 | * Authors: Adrian Hunter |
8 | * Artem Bityutskiy (Битюцкий Артём) | |
9 | */ | |
10 | ||
11 | /* | |
12 | * This file implements functions needed to recover from unclean un-mounts. | |
13 | * When UBIFS is mounted, it checks a flag on the master node to determine if | |
af901ca1 | 14 | * an un-mount was completed successfully. If not, the process of mounting |
6fb4374f | 15 | * incorporates additional checking and fixing of on-flash data structures. |
1e51764a AB |
16 | * UBIFS always cleans away all remnants of an unclean un-mount, so that |
17 | * errors do not accumulate. However UBIFS defers recovery if it is mounted | |
18 | * read-only, and the flash is not modified in that case. | |
be7b42a5 AB |
19 | * |
20 | * The general UBIFS approach to the recovery is that it recovers from | |
21 | * corruptions which could be caused by power cuts, but it refuses to recover | |
22 | * from corruption caused by other reasons. And UBIFS tries to distinguish | |
23 | * between these 2 reasons of corruptions and silently recover in the former | |
24 | * case and loudly complain in the latter case. | |
25 | * | |
26 | * UBIFS writes only to erased LEBs, so it writes only to the flash space | |
27 | * containing only 0xFFs. UBIFS also always writes strictly from the beginning | |
28 | * of the LEB to the end. And UBIFS assumes that the underlying flash media | |
2765df7d | 29 | * writes in @c->max_write_size bytes at a time. |
be7b42a5 AB |
30 | * |
31 | * Hence, if UBIFS finds a corrupted node at offset X, it expects only the min. | |
32 | * I/O unit corresponding to offset X to contain corrupted data, all the | |
33 | * following min. I/O units have to contain empty space (all 0xFFs). If this is | |
34 | * not true, the corruption cannot be the result of a power cut, and UBIFS | |
35 | * refuses to mount. | |
1e51764a AB |
36 | */ |
37 | ||
38 | #include <linux/crc32.h> | |
5a0e3ad6 | 39 | #include <linux/slab.h> |
1e51764a AB |
40 | #include "ubifs.h" |
41 | ||
42 | /** | |
43 | * is_empty - determine whether a buffer is empty (contains all 0xff). | |
44 | * @buf: buffer to clean | |
45 | * @len: length of buffer | |
46 | * | |
47 | * This function returns %1 if the buffer is empty (contains all 0xff) otherwise | |
48 | * %0 is returned. | |
49 | */ | |
50 | static int is_empty(void *buf, int len) | |
51 | { | |
52 | uint8_t *p = buf; | |
53 | int i; | |
54 | ||
55 | for (i = 0; i < len; i++) | |
56 | if (*p++ != 0xff) | |
57 | return 0; | |
58 | return 1; | |
59 | } | |
60 | ||
06112547 AB |
61 | /** |
62 | * first_non_ff - find offset of the first non-0xff byte. | |
63 | * @buf: buffer to search in | |
64 | * @len: length of buffer | |
65 | * | |
66 | * This function returns offset of the first non-0xff byte in @buf or %-1 if | |
67 | * the buffer contains only 0xff bytes. | |
68 | */ | |
69 | static int first_non_ff(void *buf, int len) | |
70 | { | |
71 | uint8_t *p = buf; | |
72 | int i; | |
73 | ||
74 | for (i = 0; i < len; i++) | |
75 | if (*p++ != 0xff) | |
76 | return i; | |
77 | return -1; | |
78 | } | |
79 | ||
1e51764a AB |
80 | /** |
81 | * get_master_node - get the last valid master node allowing for corruption. | |
82 | * @c: UBIFS file-system description object | |
83 | * @lnum: LEB number | |
84 | * @pbuf: buffer containing the LEB read, is returned here | |
85 | * @mst: master node, if found, is returned here | |
86 | * @cor: corruption, if found, is returned here | |
87 | * | |
88 | * This function allocates a buffer, reads the LEB into it, and finds and | |
89 | * returns the last valid master node allowing for one area of corruption. | |
90 | * The corrupt area, if there is one, must be consistent with the assumption | |
91 | * that it is the result of an unclean unmount while the master node was being | |
92 | * written. Under those circumstances, it is valid to use the previously written | |
93 | * master node. | |
94 | * | |
95 | * This function returns %0 on success and a negative error code on failure. | |
96 | */ | |
97 | static int get_master_node(const struct ubifs_info *c, int lnum, void **pbuf, | |
98 | struct ubifs_mst_node **mst, void **cor) | |
99 | { | |
100 | const int sz = c->mst_node_alsz; | |
101 | int err, offs, len; | |
102 | void *sbuf, *buf; | |
103 | ||
104 | sbuf = vmalloc(c->leb_size); | |
105 | if (!sbuf) | |
106 | return -ENOMEM; | |
107 | ||
d304820a | 108 | err = ubifs_leb_read(c, lnum, sbuf, 0, c->leb_size, 0); |
1e51764a AB |
109 | if (err && err != -EBADMSG) |
110 | goto out_free; | |
111 | ||
112 | /* Find the first position that is definitely not a node */ | |
113 | offs = 0; | |
114 | buf = sbuf; | |
115 | len = c->leb_size; | |
116 | while (offs + UBIFS_MST_NODE_SZ <= c->leb_size) { | |
117 | struct ubifs_ch *ch = buf; | |
118 | ||
119 | if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC) | |
120 | break; | |
121 | offs += sz; | |
122 | buf += sz; | |
123 | len -= sz; | |
124 | } | |
125 | /* See if there was a valid master node before that */ | |
126 | if (offs) { | |
127 | int ret; | |
128 | ||
129 | offs -= sz; | |
130 | buf -= sz; | |
131 | len += sz; | |
132 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1); | |
133 | if (ret != SCANNED_A_NODE && offs) { | |
134 | /* Could have been corruption so check one place back */ | |
135 | offs -= sz; | |
136 | buf -= sz; | |
137 | len += sz; | |
138 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1); | |
139 | if (ret != SCANNED_A_NODE) | |
140 | /* | |
141 | * We accept only one area of corruption because | |
142 | * we are assuming that it was caused while | |
143 | * trying to write a master node. | |
144 | */ | |
145 | goto out_err; | |
146 | } | |
147 | if (ret == SCANNED_A_NODE) { | |
148 | struct ubifs_ch *ch = buf; | |
149 | ||
150 | if (ch->node_type != UBIFS_MST_NODE) | |
151 | goto out_err; | |
152 | dbg_rcvry("found a master node at %d:%d", lnum, offs); | |
153 | *mst = buf; | |
154 | offs += sz; | |
155 | buf += sz; | |
156 | len -= sz; | |
157 | } | |
158 | } | |
159 | /* Check for corruption */ | |
160 | if (offs < c->leb_size) { | |
161 | if (!is_empty(buf, min_t(int, len, sz))) { | |
162 | *cor = buf; | |
163 | dbg_rcvry("found corruption at %d:%d", lnum, offs); | |
164 | } | |
165 | offs += sz; | |
166 | buf += sz; | |
167 | len -= sz; | |
168 | } | |
169 | /* Check remaining empty space */ | |
170 | if (offs < c->leb_size) | |
171 | if (!is_empty(buf, len)) | |
172 | goto out_err; | |
173 | *pbuf = sbuf; | |
174 | return 0; | |
175 | ||
176 | out_err: | |
177 | err = -EINVAL; | |
178 | out_free: | |
179 | vfree(sbuf); | |
180 | *mst = NULL; | |
181 | *cor = NULL; | |
182 | return err; | |
183 | } | |
184 | ||
185 | /** | |
186 | * write_rcvrd_mst_node - write recovered master node. | |
187 | * @c: UBIFS file-system description object | |
188 | * @mst: master node | |
189 | * | |
190 | * This function returns %0 on success and a negative error code on failure. | |
191 | */ | |
192 | static int write_rcvrd_mst_node(struct ubifs_info *c, | |
193 | struct ubifs_mst_node *mst) | |
194 | { | |
195 | int err = 0, lnum = UBIFS_MST_LNUM, sz = c->mst_node_alsz; | |
0ecb9529 | 196 | __le32 save_flags; |
1e51764a AB |
197 | |
198 | dbg_rcvry("recovery"); | |
199 | ||
200 | save_flags = mst->flags; | |
0ecb9529 | 201 | mst->flags |= cpu_to_le32(UBIFS_MST_RCVRY); |
1e51764a | 202 | |
625700cc SH |
203 | err = ubifs_prepare_node_hmac(c, mst, UBIFS_MST_NODE_SZ, |
204 | offsetof(struct ubifs_mst_node, hmac), 1); | |
205 | if (err) | |
206 | goto out; | |
b36a261e | 207 | err = ubifs_leb_change(c, lnum, mst, sz); |
1e51764a AB |
208 | if (err) |
209 | goto out; | |
b36a261e | 210 | err = ubifs_leb_change(c, lnum + 1, mst, sz); |
1e51764a AB |
211 | if (err) |
212 | goto out; | |
213 | out: | |
214 | mst->flags = save_flags; | |
215 | return err; | |
216 | } | |
217 | ||
218 | /** | |
219 | * ubifs_recover_master_node - recover the master node. | |
220 | * @c: UBIFS file-system description object | |
221 | * | |
222 | * This function recovers the master node from corruption that may occur due to | |
223 | * an unclean unmount. | |
224 | * | |
225 | * This function returns %0 on success and a negative error code on failure. | |
226 | */ | |
227 | int ubifs_recover_master_node(struct ubifs_info *c) | |
228 | { | |
229 | void *buf1 = NULL, *buf2 = NULL, *cor1 = NULL, *cor2 = NULL; | |
230 | struct ubifs_mst_node *mst1 = NULL, *mst2 = NULL, *mst; | |
231 | const int sz = c->mst_node_alsz; | |
232 | int err, offs1, offs2; | |
233 | ||
234 | dbg_rcvry("recovery"); | |
235 | ||
236 | err = get_master_node(c, UBIFS_MST_LNUM, &buf1, &mst1, &cor1); | |
237 | if (err) | |
238 | goto out_free; | |
239 | ||
240 | err = get_master_node(c, UBIFS_MST_LNUM + 1, &buf2, &mst2, &cor2); | |
241 | if (err) | |
242 | goto out_free; | |
243 | ||
244 | if (mst1) { | |
245 | offs1 = (void *)mst1 - buf1; | |
246 | if ((le32_to_cpu(mst1->flags) & UBIFS_MST_RCVRY) && | |
247 | (offs1 == 0 && !cor1)) { | |
248 | /* | |
249 | * mst1 was written by recovery at offset 0 with no | |
250 | * corruption. | |
251 | */ | |
252 | dbg_rcvry("recovery recovery"); | |
253 | mst = mst1; | |
254 | } else if (mst2) { | |
255 | offs2 = (void *)mst2 - buf2; | |
256 | if (offs1 == offs2) { | |
257 | /* Same offset, so must be the same */ | |
625700cc | 258 | if (ubifs_compare_master_node(c, mst1, mst2)) |
1e51764a AB |
259 | goto out_err; |
260 | mst = mst1; | |
261 | } else if (offs2 + sz == offs1) { | |
262 | /* 1st LEB was written, 2nd was not */ | |
263 | if (cor1) | |
264 | goto out_err; | |
265 | mst = mst1; | |
19495f70 AG |
266 | } else if (offs1 == 0 && |
267 | c->leb_size - offs2 - sz < sz) { | |
1e51764a AB |
268 | /* 1st LEB was unmapped and written, 2nd not */ |
269 | if (cor1) | |
270 | goto out_err; | |
271 | mst = mst1; | |
272 | } else | |
273 | goto out_err; | |
274 | } else { | |
275 | /* | |
276 | * 2nd LEB was unmapped and about to be written, so | |
277 | * there must be only one master node in the first LEB | |
278 | * and no corruption. | |
279 | */ | |
280 | if (offs1 != 0 || cor1) | |
281 | goto out_err; | |
282 | mst = mst1; | |
283 | } | |
284 | } else { | |
285 | if (!mst2) | |
286 | goto out_err; | |
287 | /* | |
288 | * 1st LEB was unmapped and about to be written, so there must | |
289 | * be no room left in 2nd LEB. | |
290 | */ | |
291 | offs2 = (void *)mst2 - buf2; | |
292 | if (offs2 + sz + sz <= c->leb_size) | |
293 | goto out_err; | |
294 | mst = mst2; | |
295 | } | |
296 | ||
235c362b | 297 | ubifs_msg(c, "recovered master node from LEB %d", |
1e51764a AB |
298 | (mst == mst1 ? UBIFS_MST_LNUM : UBIFS_MST_LNUM + 1)); |
299 | ||
300 | memcpy(c->mst_node, mst, UBIFS_MST_NODE_SZ); | |
301 | ||
2ef13294 | 302 | if (c->ro_mount) { |
1e51764a AB |
303 | /* Read-only mode. Keep a copy for switching to rw mode */ |
304 | c->rcvrd_mst_node = kmalloc(sz, GFP_KERNEL); | |
305 | if (!c->rcvrd_mst_node) { | |
306 | err = -ENOMEM; | |
307 | goto out_free; | |
308 | } | |
309 | memcpy(c->rcvrd_mst_node, c->mst_node, UBIFS_MST_NODE_SZ); | |
6e0d9fd3 AB |
310 | |
311 | /* | |
312 | * We had to recover the master node, which means there was an | |
313 | * unclean reboot. However, it is possible that the master node | |
314 | * is clean at this point, i.e., %UBIFS_MST_DIRTY is not set. | |
315 | * E.g., consider the following chain of events: | |
316 | * | |
317 | * 1. UBIFS was cleanly unmounted, so the master node is clean | |
318 | * 2. UBIFS is being mounted R/W and starts changing the master | |
319 | * node in the first (%UBIFS_MST_LNUM). A power cut happens, | |
320 | * so this LEB ends up with some amount of garbage at the | |
321 | * end. | |
322 | * 3. UBIFS is being mounted R/O. We reach this place and | |
323 | * recover the master node from the second LEB | |
324 | * (%UBIFS_MST_LNUM + 1). But we cannot update the media | |
325 | * because we are being mounted R/O. We have to defer the | |
326 | * operation. | |
327 | * 4. However, this master node (@c->mst_node) is marked as | |
328 | * clean (since the step 1). And if we just return, the | |
329 | * mount code will be confused and won't recover the master | |
330 | * node when it is re-mounter R/W later. | |
331 | * | |
332 | * Thus, to force the recovery by marking the master node as | |
333 | * dirty. | |
334 | */ | |
335 | c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY); | |
1e51764a AB |
336 | } else { |
337 | /* Write the recovered master node */ | |
338 | c->max_sqnum = le64_to_cpu(mst->ch.sqnum) - 1; | |
339 | err = write_rcvrd_mst_node(c, c->mst_node); | |
340 | if (err) | |
341 | goto out_free; | |
342 | } | |
343 | ||
344 | vfree(buf2); | |
345 | vfree(buf1); | |
346 | ||
347 | return 0; | |
348 | ||
349 | out_err: | |
350 | err = -EINVAL; | |
351 | out_free: | |
235c362b | 352 | ubifs_err(c, "failed to recover master node"); |
1e51764a | 353 | if (mst1) { |
235c362b | 354 | ubifs_err(c, "dumping first master node"); |
edf6be24 | 355 | ubifs_dump_node(c, mst1); |
1e51764a AB |
356 | } |
357 | if (mst2) { | |
235c362b | 358 | ubifs_err(c, "dumping second master node"); |
edf6be24 | 359 | ubifs_dump_node(c, mst2); |
1e51764a AB |
360 | } |
361 | vfree(buf2); | |
362 | vfree(buf1); | |
363 | return err; | |
364 | } | |
365 | ||
366 | /** | |
367 | * ubifs_write_rcvrd_mst_node - write the recovered master node. | |
368 | * @c: UBIFS file-system description object | |
369 | * | |
370 | * This function writes the master node that was recovered during mounting in | |
371 | * read-only mode and must now be written because we are remounting rw. | |
372 | * | |
373 | * This function returns %0 on success and a negative error code on failure. | |
374 | */ | |
375 | int ubifs_write_rcvrd_mst_node(struct ubifs_info *c) | |
376 | { | |
377 | int err; | |
378 | ||
379 | if (!c->rcvrd_mst_node) | |
380 | return 0; | |
381 | c->rcvrd_mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY); | |
382 | c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY); | |
383 | err = write_rcvrd_mst_node(c, c->rcvrd_mst_node); | |
384 | if (err) | |
385 | return err; | |
386 | kfree(c->rcvrd_mst_node); | |
387 | c->rcvrd_mst_node = NULL; | |
388 | return 0; | |
389 | } | |
390 | ||
391 | /** | |
392 | * is_last_write - determine if an offset was in the last write to a LEB. | |
393 | * @c: UBIFS file-system description object | |
394 | * @buf: buffer to check | |
395 | * @offs: offset to check | |
396 | * | |
397 | * This function returns %1 if @offs was in the last write to the LEB whose data | |
2765df7d AB |
398 | * is in @buf, otherwise %0 is returned. The determination is made by checking |
399 | * for subsequent empty space starting from the next @c->max_write_size | |
400 | * boundary. | |
1e51764a AB |
401 | */ |
402 | static int is_last_write(const struct ubifs_info *c, void *buf, int offs) | |
403 | { | |
428ff9d2 | 404 | int empty_offs, check_len; |
1e51764a AB |
405 | uint8_t *p; |
406 | ||
1e51764a | 407 | /* |
2765df7d AB |
408 | * Round up to the next @c->max_write_size boundary i.e. @offs is in |
409 | * the last wbuf written. After that should be empty space. | |
1e51764a | 410 | */ |
2765df7d | 411 | empty_offs = ALIGN(offs + 1, c->max_write_size); |
1e51764a AB |
412 | check_len = c->leb_size - empty_offs; |
413 | p = buf + empty_offs - offs; | |
431102fe | 414 | return is_empty(p, check_len); |
1e51764a AB |
415 | } |
416 | ||
417 | /** | |
418 | * clean_buf - clean the data from an LEB sitting in a buffer. | |
419 | * @c: UBIFS file-system description object | |
420 | * @buf: buffer to clean | |
421 | * @lnum: LEB number to clean | |
422 | * @offs: offset from which to clean | |
423 | * @len: length of buffer | |
424 | * | |
425 | * This function pads up to the next min_io_size boundary (if there is one) and | |
426 | * sets empty space to all 0xff. @buf, @offs and @len are updated to the next | |
428ff9d2 | 427 | * @c->min_io_size boundary. |
1e51764a AB |
428 | */ |
429 | static void clean_buf(const struct ubifs_info *c, void **buf, int lnum, | |
430 | int *offs, int *len) | |
431 | { | |
432 | int empty_offs, pad_len; | |
433 | ||
1e51764a AB |
434 | dbg_rcvry("cleaning corruption at %d:%d", lnum, *offs); |
435 | ||
6eb61d58 | 436 | ubifs_assert(c, !(*offs & 7)); |
1e51764a AB |
437 | empty_offs = ALIGN(*offs, c->min_io_size); |
438 | pad_len = empty_offs - *offs; | |
439 | ubifs_pad(c, *buf, pad_len); | |
440 | *offs += pad_len; | |
441 | *buf += pad_len; | |
442 | *len -= pad_len; | |
443 | memset(*buf, 0xff, c->leb_size - empty_offs); | |
444 | } | |
445 | ||
446 | /** | |
447 | * no_more_nodes - determine if there are no more nodes in a buffer. | |
448 | * @c: UBIFS file-system description object | |
449 | * @buf: buffer to check | |
450 | * @len: length of buffer | |
451 | * @lnum: LEB number of the LEB from which @buf was read | |
452 | * @offs: offset from which @buf was read | |
453 | * | |
de097578 AH |
454 | * This function ensures that the corrupted node at @offs is the last thing |
455 | * written to a LEB. This function returns %1 if more data is not found and | |
456 | * %0 if more data is found. | |
1e51764a AB |
457 | */ |
458 | static int no_more_nodes(const struct ubifs_info *c, void *buf, int len, | |
459 | int lnum, int offs) | |
460 | { | |
de097578 AH |
461 | struct ubifs_ch *ch = buf; |
462 | int skip, dlen = le32_to_cpu(ch->len); | |
1e51764a | 463 | |
de097578 | 464 | /* Check for empty space after the corrupt node's common header */ |
2765df7d | 465 | skip = ALIGN(offs + UBIFS_CH_SZ, c->max_write_size) - offs; |
de097578 AH |
466 | if (is_empty(buf + skip, len - skip)) |
467 | return 1; | |
468 | /* | |
469 | * The area after the common header size is not empty, so the common | |
470 | * header must be intact. Check it. | |
471 | */ | |
472 | if (ubifs_check_node(c, buf, lnum, offs, 1, 0) != -EUCLEAN) { | |
473 | dbg_rcvry("unexpected bad common header at %d:%d", lnum, offs); | |
474 | return 0; | |
1e51764a | 475 | } |
de097578 | 476 | /* Now we know the corrupt node's length we can skip over it */ |
2765df7d | 477 | skip = ALIGN(offs + dlen, c->max_write_size) - offs; |
de097578 AH |
478 | /* After which there should be empty space */ |
479 | if (is_empty(buf + skip, len - skip)) | |
480 | return 1; | |
481 | dbg_rcvry("unexpected data at %d:%d", lnum, offs + skip); | |
482 | return 0; | |
1e51764a AB |
483 | } |
484 | ||
485 | /** | |
486 | * fix_unclean_leb - fix an unclean LEB. | |
487 | * @c: UBIFS file-system description object | |
488 | * @sleb: scanned LEB information | |
489 | * @start: offset where scan started | |
490 | */ | |
491 | static int fix_unclean_leb(struct ubifs_info *c, struct ubifs_scan_leb *sleb, | |
492 | int start) | |
493 | { | |
494 | int lnum = sleb->lnum, endpt = start; | |
495 | ||
496 | /* Get the end offset of the last node we are keeping */ | |
497 | if (!list_empty(&sleb->nodes)) { | |
498 | struct ubifs_scan_node *snod; | |
499 | ||
500 | snod = list_entry(sleb->nodes.prev, | |
501 | struct ubifs_scan_node, list); | |
502 | endpt = snod->offs + snod->len; | |
503 | } | |
504 | ||
2ef13294 | 505 | if (c->ro_mount && !c->remounting_rw) { |
1e51764a AB |
506 | /* Add to recovery list */ |
507 | struct ubifs_unclean_leb *ucleb; | |
508 | ||
509 | dbg_rcvry("need to fix LEB %d start %d endpt %d", | |
510 | lnum, start, sleb->endpt); | |
511 | ucleb = kzalloc(sizeof(struct ubifs_unclean_leb), GFP_NOFS); | |
512 | if (!ucleb) | |
513 | return -ENOMEM; | |
514 | ucleb->lnum = lnum; | |
515 | ucleb->endpt = endpt; | |
516 | list_add_tail(&ucleb->list, &c->unclean_leb_list); | |
517 | } else { | |
518 | /* Write the fixed LEB back to flash */ | |
519 | int err; | |
520 | ||
521 | dbg_rcvry("fixing LEB %d start %d endpt %d", | |
522 | lnum, start, sleb->endpt); | |
523 | if (endpt == 0) { | |
524 | err = ubifs_leb_unmap(c, lnum); | |
525 | if (err) | |
526 | return err; | |
527 | } else { | |
528 | int len = ALIGN(endpt, c->min_io_size); | |
529 | ||
530 | if (start) { | |
d304820a AB |
531 | err = ubifs_leb_read(c, lnum, sleb->buf, 0, |
532 | start, 1); | |
1e51764a AB |
533 | if (err) |
534 | return err; | |
535 | } | |
536 | /* Pad to min_io_size */ | |
537 | if (len > endpt) { | |
538 | int pad_len = len - ALIGN(endpt, 8); | |
539 | ||
540 | if (pad_len > 0) { | |
541 | void *buf = sleb->buf + len - pad_len; | |
542 | ||
543 | ubifs_pad(c, buf, pad_len); | |
544 | } | |
545 | } | |
b36a261e | 546 | err = ubifs_leb_change(c, lnum, sleb->buf, len); |
1e51764a AB |
547 | if (err) |
548 | return err; | |
549 | } | |
550 | } | |
551 | return 0; | |
552 | } | |
553 | ||
554 | /** | |
da8b94ea | 555 | * drop_last_group - drop the last group of nodes. |
1e51764a AB |
556 | * @sleb: scanned LEB information |
557 | * @offs: offset of dropped nodes is returned here | |
558 | * | |
bbf2b37a | 559 | * This is a helper function for 'ubifs_recover_leb()' which drops the last |
da8b94ea | 560 | * group of nodes of the scanned LEB. |
1e51764a | 561 | */ |
da8b94ea | 562 | static void drop_last_group(struct ubifs_scan_leb *sleb, int *offs) |
1e51764a | 563 | { |
1e51764a AB |
564 | while (!list_empty(&sleb->nodes)) { |
565 | struct ubifs_scan_node *snod; | |
566 | struct ubifs_ch *ch; | |
567 | ||
568 | snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, | |
569 | list); | |
570 | ch = snod->node; | |
571 | if (ch->group_type != UBIFS_IN_NODE_GROUP) | |
da8b94ea AB |
572 | break; |
573 | ||
574 | dbg_rcvry("dropping grouped node at %d:%d", | |
575 | sleb->lnum, snod->offs); | |
576 | *offs = snod->offs; | |
577 | list_del(&snod->list); | |
578 | kfree(snod); | |
579 | sleb->nodes_cnt -= 1; | |
580 | } | |
581 | } | |
582 | ||
583 | /** | |
584 | * drop_last_node - drop the last node. | |
585 | * @sleb: scanned LEB information | |
586 | * @offs: offset of dropped nodes is returned here | |
da8b94ea AB |
587 | * |
588 | * This is a helper function for 'ubifs_recover_leb()' which drops the last | |
589 | * node of the scanned LEB. | |
590 | */ | |
591 | static void drop_last_node(struct ubifs_scan_leb *sleb, int *offs) | |
592 | { | |
593 | struct ubifs_scan_node *snod; | |
594 | ||
595 | if (!list_empty(&sleb->nodes)) { | |
596 | snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, | |
597 | list); | |
598 | ||
79fda517 AB |
599 | dbg_rcvry("dropping last node at %d:%d", |
600 | sleb->lnum, snod->offs); | |
1e51764a AB |
601 | *offs = snod->offs; |
602 | list_del(&snod->list); | |
603 | kfree(snod); | |
604 | sleb->nodes_cnt -= 1; | |
1e51764a | 605 | } |
1e51764a AB |
606 | } |
607 | ||
608 | /** | |
609 | * ubifs_recover_leb - scan and recover a LEB. | |
610 | * @c: UBIFS file-system description object | |
611 | * @lnum: LEB number | |
612 | * @offs: offset | |
613 | * @sbuf: LEB-sized buffer to use | |
efcfde54 AB |
614 | * @jhead: journal head number this LEB belongs to (%-1 if the LEB does not |
615 | * belong to any journal head) | |
1e51764a AB |
616 | * |
617 | * This function does a scan of a LEB, but caters for errors that might have | |
618 | * been caused by the unclean unmount from which we are attempting to recover. | |
f2b6521a | 619 | * Returns the scanned information on success and a negative error code on |
d685c412 | 620 | * failure. |
1e51764a AB |
621 | */ |
622 | struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum, | |
efcfde54 | 623 | int offs, void *sbuf, int jhead) |
1e51764a | 624 | { |
bbf2b37a | 625 | int ret = 0, err, len = c->leb_size - offs, start = offs, min_io_unit; |
efcfde54 | 626 | int grouped = jhead == -1 ? 0 : c->jheads[jhead].grouped; |
1e51764a AB |
627 | struct ubifs_scan_leb *sleb; |
628 | void *buf = sbuf + offs; | |
629 | ||
efcfde54 | 630 | dbg_rcvry("%d:%d, jhead %d, grouped %d", lnum, offs, jhead, grouped); |
1e51764a AB |
631 | |
632 | sleb = ubifs_start_scan(c, lnum, offs, sbuf); | |
633 | if (IS_ERR(sleb)) | |
634 | return sleb; | |
635 | ||
6eb61d58 | 636 | ubifs_assert(c, len >= 8); |
1e51764a | 637 | while (len >= 8) { |
1e51764a AB |
638 | dbg_scan("look at LEB %d:%d (%d bytes left)", |
639 | lnum, offs, len); | |
640 | ||
641 | cond_resched(); | |
642 | ||
643 | /* | |
644 | * Scan quietly until there is an error from which we cannot | |
645 | * recover | |
646 | */ | |
ab75950b | 647 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1); |
1e51764a AB |
648 | if (ret == SCANNED_A_NODE) { |
649 | /* A valid node, and not a padding node */ | |
650 | struct ubifs_ch *ch = buf; | |
651 | int node_len; | |
652 | ||
653 | err = ubifs_add_snod(c, sleb, buf, offs); | |
654 | if (err) | |
655 | goto error; | |
656 | node_len = ALIGN(le32_to_cpu(ch->len), 8); | |
657 | offs += node_len; | |
658 | buf += node_len; | |
659 | len -= node_len; | |
61799206 | 660 | } else if (ret > 0) { |
1e51764a AB |
661 | /* Padding bytes or a valid padding node */ |
662 | offs += ret; | |
663 | buf += ret; | |
664 | len -= ret; | |
61799206 AB |
665 | } else if (ret == SCANNED_EMPTY_SPACE || |
666 | ret == SCANNED_GARBAGE || | |
667 | ret == SCANNED_A_BAD_PAD_NODE || | |
668 | ret == SCANNED_A_CORRUPT_NODE) { | |
78437368 AB |
669 | dbg_rcvry("found corruption (%d) at %d:%d", |
670 | ret, lnum, offs); | |
1e51764a | 671 | break; |
61799206 | 672 | } else { |
235c362b | 673 | ubifs_err(c, "unexpected return value %d", ret); |
ed43f2f0 AB |
674 | err = -EINVAL; |
675 | goto error; | |
1e51764a AB |
676 | } |
677 | } | |
678 | ||
61799206 | 679 | if (ret == SCANNED_GARBAGE || ret == SCANNED_A_BAD_PAD_NODE) { |
43e07073 | 680 | if (!is_last_write(c, buf, offs)) |
61799206 AB |
681 | goto corrupted_rescan; |
682 | } else if (ret == SCANNED_A_CORRUPT_NODE) { | |
43e07073 | 683 | if (!no_more_nodes(c, buf, len, lnum, offs)) |
61799206 AB |
684 | goto corrupted_rescan; |
685 | } else if (!is_empty(buf, len)) { | |
43e07073 | 686 | if (!is_last_write(c, buf, offs)) { |
06112547 AB |
687 | int corruption = first_non_ff(buf, len); |
688 | ||
be7b42a5 AB |
689 | /* |
690 | * See header comment for this file for more | |
691 | * explanations about the reasons we have this check. | |
692 | */ | |
235c362b | 693 | ubifs_err(c, "corrupt empty space LEB %d:%d, corruption starts at %d", |
79fda517 | 694 | lnum, offs, corruption); |
06112547 | 695 | /* Make sure we dump interesting non-0xFF data */ |
10ac2797 | 696 | offs += corruption; |
06112547 | 697 | buf += corruption; |
1e51764a AB |
698 | goto corrupted; |
699 | } | |
700 | } | |
701 | ||
bbf2b37a AB |
702 | min_io_unit = round_down(offs, c->min_io_size); |
703 | if (grouped) | |
704 | /* | |
705 | * If nodes are grouped, always drop the incomplete group at | |
706 | * the end. | |
707 | */ | |
da8b94ea | 708 | drop_last_group(sleb, &offs); |
bbf2b37a | 709 | |
da8b94ea AB |
710 | if (jhead == GCHD) { |
711 | /* | |
712 | * If this LEB belongs to the GC head then while we are in the | |
713 | * middle of the same min. I/O unit keep dropping nodes. So | |
714 | * basically, what we want is to make sure that the last min. | |
715 | * I/O unit where we saw the corruption is dropped completely | |
716 | * with all the uncorrupted nodes which may possibly sit there. | |
717 | * | |
718 | * In other words, let's name the min. I/O unit where the | |
719 | * corruption starts B, and the previous min. I/O unit A. The | |
720 | * below code tries to deal with a situation when half of B | |
721 | * contains valid nodes or the end of a valid node, and the | |
722 | * second half of B contains corrupted data or garbage. This | |
723 | * means that UBIFS had been writing to B just before the power | |
724 | * cut happened. I do not know how realistic is this scenario | |
725 | * that half of the min. I/O unit had been written successfully | |
726 | * and the other half not, but this is possible in our 'failure | |
727 | * mode emulation' infrastructure at least. | |
728 | * | |
729 | * So what is the problem, why we need to drop those nodes? Why | |
730 | * can't we just clean-up the second half of B by putting a | |
731 | * padding node there? We can, and this works fine with one | |
732 | * exception which was reproduced with power cut emulation | |
733 | * testing and happens extremely rarely. | |
734 | * | |
735 | * Imagine the file-system is full, we run GC which starts | |
736 | * moving valid nodes from LEB X to LEB Y (obviously, LEB Y is | |
737 | * the current GC head LEB). The @c->gc_lnum is -1, which means | |
738 | * that GC will retain LEB X and will try to continue. Imagine | |
739 | * that LEB X is currently the dirtiest LEB, and the amount of | |
740 | * used space in LEB Y is exactly the same as amount of free | |
741 | * space in LEB X. | |
742 | * | |
743 | * And a power cut happens when nodes are moved from LEB X to | |
744 | * LEB Y. We are here trying to recover LEB Y which is the GC | |
745 | * head LEB. We find the min. I/O unit B as described above. | |
746 | * Then we clean-up LEB Y by padding min. I/O unit. And later | |
747 | * 'ubifs_rcvry_gc_commit()' function fails, because it cannot | |
748 | * find a dirty LEB which could be GC'd into LEB Y! Even LEB X | |
749 | * does not match because the amount of valid nodes there does | |
750 | * not fit the free space in LEB Y any more! And this is | |
751 | * because of the padding node which we added to LEB Y. The | |
752 | * user-visible effect of this which I once observed and | |
753 | * analysed is that we cannot mount the file-system with | |
754 | * -ENOSPC error. | |
755 | * | |
756 | * So obviously, to make sure that situation does not happen we | |
757 | * should free min. I/O unit B in LEB Y completely and the last | |
758 | * used min. I/O unit in LEB Y should be A. This is basically | |
759 | * what the below code tries to do. | |
760 | */ | |
761 | while (offs > min_io_unit) | |
762 | drop_last_node(sleb, &offs); | |
763 | } | |
bbf2b37a AB |
764 | |
765 | buf = sbuf + offs; | |
766 | len = c->leb_size - offs; | |
1e51764a | 767 | |
43e07073 | 768 | clean_buf(c, &buf, lnum, &offs, &len); |
1e51764a AB |
769 | ubifs_end_scan(c, sleb, lnum, offs); |
770 | ||
7c47bfd0 AB |
771 | err = fix_unclean_leb(c, sleb, start); |
772 | if (err) | |
773 | goto error; | |
1e51764a AB |
774 | |
775 | return sleb; | |
776 | ||
61799206 AB |
777 | corrupted_rescan: |
778 | /* Re-scan the corrupted data with verbose messages */ | |
235c362b | 779 | ubifs_err(c, "corruption %d", ret); |
be186cc4 | 780 | ubifs_scan_a_node(c, buf, len, lnum, offs, 0); |
1e51764a AB |
781 | corrupted: |
782 | ubifs_scanned_corruption(c, lnum, offs, buf); | |
783 | err = -EUCLEAN; | |
784 | error: | |
235c362b | 785 | ubifs_err(c, "LEB %d scanning failed", lnum); |
1e51764a AB |
786 | ubifs_scan_destroy(sleb); |
787 | return ERR_PTR(err); | |
788 | } | |
789 | ||
790 | /** | |
791 | * get_cs_sqnum - get commit start sequence number. | |
792 | * @c: UBIFS file-system description object | |
793 | * @lnum: LEB number of commit start node | |
794 | * @offs: offset of commit start node | |
795 | * @cs_sqnum: commit start sequence number is returned here | |
796 | * | |
797 | * This function returns %0 on success and a negative error code on failure. | |
798 | */ | |
799 | static int get_cs_sqnum(struct ubifs_info *c, int lnum, int offs, | |
800 | unsigned long long *cs_sqnum) | |
801 | { | |
802 | struct ubifs_cs_node *cs_node = NULL; | |
803 | int err, ret; | |
804 | ||
805 | dbg_rcvry("at %d:%d", lnum, offs); | |
806 | cs_node = kmalloc(UBIFS_CS_NODE_SZ, GFP_KERNEL); | |
807 | if (!cs_node) | |
808 | return -ENOMEM; | |
809 | if (c->leb_size - offs < UBIFS_CS_NODE_SZ) | |
810 | goto out_err; | |
d304820a AB |
811 | err = ubifs_leb_read(c, lnum, (void *)cs_node, offs, |
812 | UBIFS_CS_NODE_SZ, 0); | |
1e51764a AB |
813 | if (err && err != -EBADMSG) |
814 | goto out_free; | |
815 | ret = ubifs_scan_a_node(c, cs_node, UBIFS_CS_NODE_SZ, lnum, offs, 0); | |
816 | if (ret != SCANNED_A_NODE) { | |
235c362b | 817 | ubifs_err(c, "Not a valid node"); |
1e51764a AB |
818 | goto out_err; |
819 | } | |
820 | if (cs_node->ch.node_type != UBIFS_CS_NODE) { | |
7d8c811b | 821 | ubifs_err(c, "Not a CS node, type is %d", cs_node->ch.node_type); |
1e51764a AB |
822 | goto out_err; |
823 | } | |
824 | if (le64_to_cpu(cs_node->cmt_no) != c->cmt_no) { | |
235c362b | 825 | ubifs_err(c, "CS node cmt_no %llu != current cmt_no %llu", |
a6aae4dd AB |
826 | (unsigned long long)le64_to_cpu(cs_node->cmt_no), |
827 | c->cmt_no); | |
1e51764a AB |
828 | goto out_err; |
829 | } | |
830 | *cs_sqnum = le64_to_cpu(cs_node->ch.sqnum); | |
831 | dbg_rcvry("commit start sqnum %llu", *cs_sqnum); | |
832 | kfree(cs_node); | |
833 | return 0; | |
834 | ||
835 | out_err: | |
836 | err = -EINVAL; | |
837 | out_free: | |
235c362b | 838 | ubifs_err(c, "failed to get CS sqnum"); |
1e51764a AB |
839 | kfree(cs_node); |
840 | return err; | |
841 | } | |
842 | ||
843 | /** | |
844 | * ubifs_recover_log_leb - scan and recover a log LEB. | |
845 | * @c: UBIFS file-system description object | |
846 | * @lnum: LEB number | |
847 | * @offs: offset | |
848 | * @sbuf: LEB-sized buffer to use | |
849 | * | |
850 | * This function does a scan of a LEB, but caters for errors that might have | |
7d08ae3c AB |
851 | * been caused by unclean reboots from which we are attempting to recover |
852 | * (assume that only the last log LEB can be corrupted by an unclean reboot). | |
1e51764a AB |
853 | * |
854 | * This function returns %0 on success and a negative error code on failure. | |
855 | */ | |
856 | struct ubifs_scan_leb *ubifs_recover_log_leb(struct ubifs_info *c, int lnum, | |
857 | int offs, void *sbuf) | |
858 | { | |
859 | struct ubifs_scan_leb *sleb; | |
860 | int next_lnum; | |
861 | ||
862 | dbg_rcvry("LEB %d", lnum); | |
863 | next_lnum = lnum + 1; | |
864 | if (next_lnum >= UBIFS_LOG_LNUM + c->log_lebs) | |
865 | next_lnum = UBIFS_LOG_LNUM; | |
866 | if (next_lnum != c->ltail_lnum) { | |
867 | /* | |
868 | * We can only recover at the end of the log, so check that the | |
869 | * next log LEB is empty or out of date. | |
870 | */ | |
348709ba | 871 | sleb = ubifs_scan(c, next_lnum, 0, sbuf, 0); |
1e51764a AB |
872 | if (IS_ERR(sleb)) |
873 | return sleb; | |
874 | if (sleb->nodes_cnt) { | |
875 | struct ubifs_scan_node *snod; | |
876 | unsigned long long cs_sqnum = c->cs_sqnum; | |
877 | ||
878 | snod = list_entry(sleb->nodes.next, | |
879 | struct ubifs_scan_node, list); | |
880 | if (cs_sqnum == 0) { | |
881 | int err; | |
882 | ||
883 | err = get_cs_sqnum(c, lnum, offs, &cs_sqnum); | |
884 | if (err) { | |
885 | ubifs_scan_destroy(sleb); | |
886 | return ERR_PTR(err); | |
887 | } | |
888 | } | |
889 | if (snod->sqnum > cs_sqnum) { | |
235c362b | 890 | ubifs_err(c, "unrecoverable log corruption in LEB %d", |
79fda517 | 891 | lnum); |
1e51764a AB |
892 | ubifs_scan_destroy(sleb); |
893 | return ERR_PTR(-EUCLEAN); | |
894 | } | |
895 | } | |
896 | ubifs_scan_destroy(sleb); | |
897 | } | |
efcfde54 | 898 | return ubifs_recover_leb(c, lnum, offs, sbuf, -1); |
1e51764a AB |
899 | } |
900 | ||
901 | /** | |
902 | * recover_head - recover a head. | |
903 | * @c: UBIFS file-system description object | |
904 | * @lnum: LEB number of head to recover | |
905 | * @offs: offset of head to recover | |
906 | * @sbuf: LEB-sized buffer to use | |
907 | * | |
908 | * This function ensures that there is no data on the flash at a head location. | |
909 | * | |
910 | * This function returns %0 on success and a negative error code on failure. | |
911 | */ | |
83cef708 | 912 | static int recover_head(struct ubifs_info *c, int lnum, int offs, void *sbuf) |
1e51764a | 913 | { |
2765df7d | 914 | int len = c->max_write_size, err; |
1e51764a | 915 | |
1e51764a AB |
916 | if (offs + len > c->leb_size) |
917 | len = c->leb_size - offs; | |
918 | ||
919 | if (!len) | |
920 | return 0; | |
921 | ||
922 | /* Read at the head location and check it is empty flash */ | |
d304820a | 923 | err = ubifs_leb_read(c, lnum, sbuf, offs, len, 1); |
431102fe | 924 | if (err || !is_empty(sbuf, len)) { |
1e51764a AB |
925 | dbg_rcvry("cleaning head at %d:%d", lnum, offs); |
926 | if (offs == 0) | |
927 | return ubifs_leb_unmap(c, lnum); | |
d304820a | 928 | err = ubifs_leb_read(c, lnum, sbuf, 0, offs, 1); |
1e51764a AB |
929 | if (err) |
930 | return err; | |
b36a261e | 931 | return ubifs_leb_change(c, lnum, sbuf, offs); |
1e51764a AB |
932 | } |
933 | ||
934 | return 0; | |
935 | } | |
936 | ||
937 | /** | |
938 | * ubifs_recover_inl_heads - recover index and LPT heads. | |
939 | * @c: UBIFS file-system description object | |
940 | * @sbuf: LEB-sized buffer to use | |
941 | * | |
942 | * This function ensures that there is no data on the flash at the index and | |
943 | * LPT head locations. | |
944 | * | |
945 | * This deals with the recovery of a half-completed journal commit. UBIFS is | |
946 | * careful never to overwrite the last version of the index or the LPT. Because | |
947 | * the index and LPT are wandering trees, data from a half-completed commit will | |
948 | * not be referenced anywhere in UBIFS. The data will be either in LEBs that are | |
949 | * assumed to be empty and will be unmapped anyway before use, or in the index | |
950 | * and LPT heads. | |
951 | * | |
952 | * This function returns %0 on success and a negative error code on failure. | |
953 | */ | |
83cef708 | 954 | int ubifs_recover_inl_heads(struct ubifs_info *c, void *sbuf) |
1e51764a AB |
955 | { |
956 | int err; | |
957 | ||
6eb61d58 | 958 | ubifs_assert(c, !c->ro_mount || c->remounting_rw); |
1e51764a AB |
959 | |
960 | dbg_rcvry("checking index head at %d:%d", c->ihead_lnum, c->ihead_offs); | |
961 | err = recover_head(c, c->ihead_lnum, c->ihead_offs, sbuf); | |
962 | if (err) | |
963 | return err; | |
964 | ||
965 | dbg_rcvry("checking LPT head at %d:%d", c->nhead_lnum, c->nhead_offs); | |
1e51764a | 966 | |
8a87dc55 | 967 | return recover_head(c, c->nhead_lnum, c->nhead_offs, sbuf); |
1e51764a AB |
968 | } |
969 | ||
970 | /** | |
7606f85a | 971 | * clean_an_unclean_leb - read and write a LEB to remove corruption. |
1e51764a AB |
972 | * @c: UBIFS file-system description object |
973 | * @ucleb: unclean LEB information | |
974 | * @sbuf: LEB-sized buffer to use | |
975 | * | |
976 | * This function reads a LEB up to a point pre-determined by the mount recovery, | |
977 | * checks the nodes, and writes the result back to the flash, thereby cleaning | |
978 | * off any following corruption, or non-fatal ECC errors. | |
979 | * | |
980 | * This function returns %0 on success and a negative error code on failure. | |
981 | */ | |
83cef708 | 982 | static int clean_an_unclean_leb(struct ubifs_info *c, |
1e51764a AB |
983 | struct ubifs_unclean_leb *ucleb, void *sbuf) |
984 | { | |
985 | int err, lnum = ucleb->lnum, offs = 0, len = ucleb->endpt, quiet = 1; | |
986 | void *buf = sbuf; | |
987 | ||
988 | dbg_rcvry("LEB %d len %d", lnum, len); | |
989 | ||
990 | if (len == 0) { | |
991 | /* Nothing to read, just unmap it */ | |
8a87dc55 | 992 | return ubifs_leb_unmap(c, lnum); |
1e51764a AB |
993 | } |
994 | ||
d304820a | 995 | err = ubifs_leb_read(c, lnum, buf, offs, len, 0); |
1e51764a AB |
996 | if (err && err != -EBADMSG) |
997 | return err; | |
998 | ||
999 | while (len >= 8) { | |
1000 | int ret; | |
1001 | ||
1002 | cond_resched(); | |
1003 | ||
1004 | /* Scan quietly until there is an error */ | |
1005 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet); | |
1006 | ||
1007 | if (ret == SCANNED_A_NODE) { | |
1008 | /* A valid node, and not a padding node */ | |
1009 | struct ubifs_ch *ch = buf; | |
1010 | int node_len; | |
1011 | ||
1012 | node_len = ALIGN(le32_to_cpu(ch->len), 8); | |
1013 | offs += node_len; | |
1014 | buf += node_len; | |
1015 | len -= node_len; | |
1016 | continue; | |
1017 | } | |
1018 | ||
1019 | if (ret > 0) { | |
1020 | /* Padding bytes or a valid padding node */ | |
1021 | offs += ret; | |
1022 | buf += ret; | |
1023 | len -= ret; | |
1024 | continue; | |
1025 | } | |
1026 | ||
1027 | if (ret == SCANNED_EMPTY_SPACE) { | |
235c362b | 1028 | ubifs_err(c, "unexpected empty space at %d:%d", |
1e51764a AB |
1029 | lnum, offs); |
1030 | return -EUCLEAN; | |
1031 | } | |
1032 | ||
1033 | if (quiet) { | |
1034 | /* Redo the last scan but noisily */ | |
1035 | quiet = 0; | |
1036 | continue; | |
1037 | } | |
1038 | ||
1039 | ubifs_scanned_corruption(c, lnum, offs, buf); | |
1040 | return -EUCLEAN; | |
1041 | } | |
1042 | ||
1043 | /* Pad to min_io_size */ | |
1044 | len = ALIGN(ucleb->endpt, c->min_io_size); | |
1045 | if (len > ucleb->endpt) { | |
1046 | int pad_len = len - ALIGN(ucleb->endpt, 8); | |
1047 | ||
1048 | if (pad_len > 0) { | |
1049 | buf = c->sbuf + len - pad_len; | |
1050 | ubifs_pad(c, buf, pad_len); | |
1051 | } | |
1052 | } | |
1053 | ||
1054 | /* Write back the LEB atomically */ | |
b36a261e | 1055 | err = ubifs_leb_change(c, lnum, sbuf, len); |
1e51764a AB |
1056 | if (err) |
1057 | return err; | |
1058 | ||
1059 | dbg_rcvry("cleaned LEB %d", lnum); | |
1060 | ||
1061 | return 0; | |
1062 | } | |
1063 | ||
1064 | /** | |
1065 | * ubifs_clean_lebs - clean LEBs recovered during read-only mount. | |
1066 | * @c: UBIFS file-system description object | |
1067 | * @sbuf: LEB-sized buffer to use | |
1068 | * | |
1069 | * This function cleans a LEB identified during recovery that needs to be | |
1070 | * written but was not because UBIFS was mounted read-only. This happens when | |
1071 | * remounting to read-write mode. | |
1072 | * | |
1073 | * This function returns %0 on success and a negative error code on failure. | |
1074 | */ | |
83cef708 | 1075 | int ubifs_clean_lebs(struct ubifs_info *c, void *sbuf) |
1e51764a AB |
1076 | { |
1077 | dbg_rcvry("recovery"); | |
1078 | while (!list_empty(&c->unclean_leb_list)) { | |
1079 | struct ubifs_unclean_leb *ucleb; | |
1080 | int err; | |
1081 | ||
1082 | ucleb = list_entry(c->unclean_leb_list.next, | |
1083 | struct ubifs_unclean_leb, list); | |
1084 | err = clean_an_unclean_leb(c, ucleb, sbuf); | |
1085 | if (err) | |
1086 | return err; | |
1087 | list_del(&ucleb->list); | |
1088 | kfree(ucleb); | |
1089 | } | |
1090 | return 0; | |
1091 | } | |
1092 | ||
44744213 AB |
1093 | /** |
1094 | * grab_empty_leb - grab an empty LEB to use as GC LEB and run commit. | |
1095 | * @c: UBIFS file-system description object | |
1096 | * | |
1097 | * This is a helper function for 'ubifs_rcvry_gc_commit()' which grabs an empty | |
1098 | * LEB to be used as GC LEB (@c->gc_lnum), and then runs the commit. Returns | |
1099 | * zero in case of success and a negative error code in case of failure. | |
1100 | */ | |
1101 | static int grab_empty_leb(struct ubifs_info *c) | |
1102 | { | |
1103 | int lnum, err; | |
1104 | ||
1105 | /* | |
1106 | * Note, it is very important to first search for an empty LEB and then | |
1107 | * run the commit, not vice-versa. The reason is that there might be | |
1108 | * only one empty LEB at the moment, the one which has been the | |
1109 | * @c->gc_lnum just before the power cut happened. During the regular | |
1110 | * UBIFS operation (not now) @c->gc_lnum is marked as "taken", so no | |
1111 | * one but GC can grab it. But at this moment this single empty LEB is | |
1112 | * not marked as taken, so if we run commit - what happens? Right, the | |
1113 | * commit will grab it and write the index there. Remember that the | |
1114 | * index always expands as long as there is free space, and it only | |
1115 | * starts consolidating when we run out of space. | |
1116 | * | |
1117 | * IOW, if we run commit now, we might not be able to find a free LEB | |
1118 | * after this. | |
1119 | */ | |
1120 | lnum = ubifs_find_free_leb_for_idx(c); | |
1121 | if (lnum < 0) { | |
235c362b | 1122 | ubifs_err(c, "could not find an empty LEB"); |
edf6be24 AB |
1123 | ubifs_dump_lprops(c); |
1124 | ubifs_dump_budg(c, &c->bi); | |
44744213 AB |
1125 | return lnum; |
1126 | } | |
1127 | ||
1128 | /* Reset the index flag */ | |
1129 | err = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0, | |
1130 | LPROPS_INDEX, 0); | |
1131 | if (err) | |
1132 | return err; | |
1133 | ||
1134 | c->gc_lnum = lnum; | |
1135 | dbg_rcvry("found empty LEB %d, run commit", lnum); | |
1136 | ||
1137 | return ubifs_run_commit(c); | |
1138 | } | |
1139 | ||
1e51764a AB |
1140 | /** |
1141 | * ubifs_rcvry_gc_commit - recover the GC LEB number and run the commit. | |
1142 | * @c: UBIFS file-system description object | |
1143 | * | |
1144 | * Out-of-place garbage collection requires always one empty LEB with which to | |
1145 | * start garbage collection. The LEB number is recorded in c->gc_lnum and is | |
1146 | * written to the master node on unmounting. In the case of an unclean unmount | |
1147 | * the value of gc_lnum recorded in the master node is out of date and cannot | |
1148 | * be used. Instead, recovery must allocate an empty LEB for this purpose. | |
1149 | * However, there may not be enough empty space, in which case it must be | |
1150 | * possible to GC the dirtiest LEB into the GC head LEB. | |
1151 | * | |
1152 | * This function also runs the commit which causes the TNC updates from | |
1153 | * size-recovery and orphans to be written to the flash. That is important to | |
1154 | * ensure correct replay order for subsequent mounts. | |
1155 | * | |
1156 | * This function returns %0 on success and a negative error code on failure. | |
1157 | */ | |
1158 | int ubifs_rcvry_gc_commit(struct ubifs_info *c) | |
1159 | { | |
1160 | struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf; | |
1161 | struct ubifs_lprops lp; | |
fe79c05f | 1162 | int err; |
1e51764a | 1163 | |
c839e297 AB |
1164 | dbg_rcvry("GC head LEB %d, offs %d", wbuf->lnum, wbuf->offs); |
1165 | ||
1e51764a | 1166 | c->gc_lnum = -1; |
c839e297 | 1167 | if (wbuf->lnum == -1 || wbuf->offs == c->leb_size) |
44744213 | 1168 | return grab_empty_leb(c); |
fe79c05f | 1169 | |
1e51764a AB |
1170 | err = ubifs_find_dirty_leb(c, &lp, wbuf->offs, 2); |
1171 | if (err) { | |
fe79c05f AB |
1172 | if (err != -ENOSPC) |
1173 | return err; | |
1174 | ||
1175 | dbg_rcvry("could not find a dirty LEB"); | |
1176 | return grab_empty_leb(c); | |
1e51764a | 1177 | } |
2405f594 | 1178 | |
6eb61d58 RW |
1179 | ubifs_assert(c, !(lp.flags & LPROPS_INDEX)); |
1180 | ubifs_assert(c, lp.free + lp.dirty >= wbuf->offs); | |
2405f594 | 1181 | |
1e51764a AB |
1182 | /* |
1183 | * We run the commit before garbage collection otherwise subsequent | |
1184 | * mounts will see the GC and orphan deletion in a different order. | |
1185 | */ | |
1186 | dbg_rcvry("committing"); | |
1187 | err = ubifs_run_commit(c); | |
1188 | if (err) | |
1189 | return err; | |
fe79c05f AB |
1190 | |
1191 | dbg_rcvry("GC'ing LEB %d", lp.lnum); | |
1e51764a AB |
1192 | mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); |
1193 | err = ubifs_garbage_collect_leb(c, &lp); | |
1194 | if (err >= 0) { | |
1195 | int err2 = ubifs_wbuf_sync_nolock(wbuf); | |
1196 | ||
1197 | if (err2) | |
1198 | err = err2; | |
1199 | } | |
1200 | mutex_unlock(&wbuf->io_mutex); | |
1201 | if (err < 0) { | |
235c362b | 1202 | ubifs_err(c, "GC failed, error %d", err); |
1e51764a AB |
1203 | if (err == -EAGAIN) |
1204 | err = -EINVAL; | |
1205 | return err; | |
1206 | } | |
fe79c05f | 1207 | |
6eb61d58 | 1208 | ubifs_assert(c, err == LEB_RETAINED); |
fe79c05f | 1209 | if (err != LEB_RETAINED) |
1e51764a | 1210 | return -EINVAL; |
fe79c05f | 1211 | |
1e51764a AB |
1212 | err = ubifs_leb_unmap(c, c->gc_lnum); |
1213 | if (err) | |
1214 | return err; | |
fe79c05f AB |
1215 | |
1216 | dbg_rcvry("allocated LEB %d for GC", lp.lnum); | |
1e51764a | 1217 | return 0; |
1e51764a AB |
1218 | } |
1219 | ||
1220 | /** | |
1221 | * struct size_entry - inode size information for recovery. | |
1222 | * @rb: link in the RB-tree of sizes | |
1223 | * @inum: inode number | |
1224 | * @i_size: size on inode | |
1225 | * @d_size: maximum size based on data nodes | |
1226 | * @exists: indicates whether the inode exists | |
1227 | * @inode: inode if pinned in memory awaiting rw mode to fix it | |
1228 | */ | |
1229 | struct size_entry { | |
1230 | struct rb_node rb; | |
1231 | ino_t inum; | |
1232 | loff_t i_size; | |
1233 | loff_t d_size; | |
1234 | int exists; | |
1235 | struct inode *inode; | |
1236 | }; | |
1237 | ||
1238 | /** | |
1239 | * add_ino - add an entry to the size tree. | |
1240 | * @c: UBIFS file-system description object | |
1241 | * @inum: inode number | |
1242 | * @i_size: size on inode | |
1243 | * @d_size: maximum size based on data nodes | |
1244 | * @exists: indicates whether the inode exists | |
1245 | */ | |
1246 | static int add_ino(struct ubifs_info *c, ino_t inum, loff_t i_size, | |
1247 | loff_t d_size, int exists) | |
1248 | { | |
1249 | struct rb_node **p = &c->size_tree.rb_node, *parent = NULL; | |
1250 | struct size_entry *e; | |
1251 | ||
1252 | while (*p) { | |
1253 | parent = *p; | |
1254 | e = rb_entry(parent, struct size_entry, rb); | |
1255 | if (inum < e->inum) | |
1256 | p = &(*p)->rb_left; | |
1257 | else | |
1258 | p = &(*p)->rb_right; | |
1259 | } | |
1260 | ||
1261 | e = kzalloc(sizeof(struct size_entry), GFP_KERNEL); | |
1262 | if (!e) | |
1263 | return -ENOMEM; | |
1264 | ||
1265 | e->inum = inum; | |
1266 | e->i_size = i_size; | |
1267 | e->d_size = d_size; | |
1268 | e->exists = exists; | |
1269 | ||
1270 | rb_link_node(&e->rb, parent, p); | |
1271 | rb_insert_color(&e->rb, &c->size_tree); | |
1272 | ||
1273 | return 0; | |
1274 | } | |
1275 | ||
1276 | /** | |
1277 | * find_ino - find an entry on the size tree. | |
1278 | * @c: UBIFS file-system description object | |
1279 | * @inum: inode number | |
1280 | */ | |
1281 | static struct size_entry *find_ino(struct ubifs_info *c, ino_t inum) | |
1282 | { | |
1283 | struct rb_node *p = c->size_tree.rb_node; | |
1284 | struct size_entry *e; | |
1285 | ||
1286 | while (p) { | |
1287 | e = rb_entry(p, struct size_entry, rb); | |
1288 | if (inum < e->inum) | |
1289 | p = p->rb_left; | |
1290 | else if (inum > e->inum) | |
1291 | p = p->rb_right; | |
1292 | else | |
1293 | return e; | |
1294 | } | |
1295 | return NULL; | |
1296 | } | |
1297 | ||
1298 | /** | |
1299 | * remove_ino - remove an entry from the size tree. | |
1300 | * @c: UBIFS file-system description object | |
1301 | * @inum: inode number | |
1302 | */ | |
1303 | static void remove_ino(struct ubifs_info *c, ino_t inum) | |
1304 | { | |
1305 | struct size_entry *e = find_ino(c, inum); | |
1306 | ||
1307 | if (!e) | |
1308 | return; | |
1309 | rb_erase(&e->rb, &c->size_tree); | |
1310 | kfree(e); | |
1311 | } | |
1312 | ||
1313 | /** | |
1314 | * ubifs_destroy_size_tree - free resources related to the size tree. | |
1315 | * @c: UBIFS file-system description object | |
1316 | */ | |
1317 | void ubifs_destroy_size_tree(struct ubifs_info *c) | |
1318 | { | |
bb25e49f | 1319 | struct size_entry *e, *n; |
1e51764a | 1320 | |
bb25e49f | 1321 | rbtree_postorder_for_each_entry_safe(e, n, &c->size_tree, rb) { |
54bcfdf1 | 1322 | iput(e->inode); |
1e51764a AB |
1323 | kfree(e); |
1324 | } | |
bb25e49f | 1325 | |
1e51764a AB |
1326 | c->size_tree = RB_ROOT; |
1327 | } | |
1328 | ||
1329 | /** | |
1330 | * ubifs_recover_size_accum - accumulate inode sizes for recovery. | |
1331 | * @c: UBIFS file-system description object | |
1332 | * @key: node key | |
1333 | * @deletion: node is for a deletion | |
1334 | * @new_size: inode size | |
1335 | * | |
1336 | * This function has two purposes: | |
1337 | * 1) to ensure there are no data nodes that fall outside the inode size | |
1338 | * 2) to ensure there are no data nodes for inodes that do not exist | |
1339 | * To accomplish those purposes, a rb-tree is constructed containing an entry | |
1340 | * for each inode number in the journal that has not been deleted, and recording | |
1341 | * the size from the inode node, the maximum size of any data node (also altered | |
1342 | * by truncations) and a flag indicating a inode number for which no inode node | |
1343 | * was present in the journal. | |
1344 | * | |
1345 | * Note that there is still the possibility that there are data nodes that have | |
1346 | * been committed that are beyond the inode size, however the only way to find | |
1347 | * them would be to scan the entire index. Alternatively, some provision could | |
1348 | * be made to record the size of inodes at the start of commit, which would seem | |
1349 | * very cumbersome for a scenario that is quite unlikely and the only negative | |
1350 | * consequence of which is wasted space. | |
1351 | * | |
1352 | * This functions returns %0 on success and a negative error code on failure. | |
1353 | */ | |
1354 | int ubifs_recover_size_accum(struct ubifs_info *c, union ubifs_key *key, | |
1355 | int deletion, loff_t new_size) | |
1356 | { | |
1357 | ino_t inum = key_inum(c, key); | |
1358 | struct size_entry *e; | |
1359 | int err; | |
1360 | ||
1361 | switch (key_type(c, key)) { | |
1362 | case UBIFS_INO_KEY: | |
1363 | if (deletion) | |
1364 | remove_ino(c, inum); | |
1365 | else { | |
1366 | e = find_ino(c, inum); | |
1367 | if (e) { | |
1368 | e->i_size = new_size; | |
1369 | e->exists = 1; | |
1370 | } else { | |
1371 | err = add_ino(c, inum, new_size, 0, 1); | |
1372 | if (err) | |
1373 | return err; | |
1374 | } | |
1375 | } | |
1376 | break; | |
1377 | case UBIFS_DATA_KEY: | |
1378 | e = find_ino(c, inum); | |
1379 | if (e) { | |
1380 | if (new_size > e->d_size) | |
1381 | e->d_size = new_size; | |
1382 | } else { | |
1383 | err = add_ino(c, inum, 0, new_size, 0); | |
1384 | if (err) | |
1385 | return err; | |
1386 | } | |
1387 | break; | |
1388 | case UBIFS_TRUN_KEY: | |
1389 | e = find_ino(c, inum); | |
1390 | if (e) | |
1391 | e->d_size = new_size; | |
1392 | break; | |
1393 | } | |
1394 | return 0; | |
1395 | } | |
1396 | ||
1397 | /** | |
1398 | * fix_size_in_place - fix inode size in place on flash. | |
1399 | * @c: UBIFS file-system description object | |
1400 | * @e: inode size information for recovery | |
1401 | */ | |
1402 | static int fix_size_in_place(struct ubifs_info *c, struct size_entry *e) | |
1403 | { | |
1404 | struct ubifs_ino_node *ino = c->sbuf; | |
1405 | unsigned char *p; | |
1406 | union ubifs_key key; | |
1407 | int err, lnum, offs, len; | |
1408 | loff_t i_size; | |
1409 | uint32_t crc; | |
1410 | ||
1411 | /* Locate the inode node LEB number and offset */ | |
1412 | ino_key_init(c, &key, e->inum); | |
1413 | err = ubifs_tnc_locate(c, &key, ino, &lnum, &offs); | |
1414 | if (err) | |
1415 | goto out; | |
1416 | /* | |
1417 | * If the size recorded on the inode node is greater than the size that | |
1418 | * was calculated from nodes in the journal then don't change the inode. | |
1419 | */ | |
1420 | i_size = le64_to_cpu(ino->size); | |
1421 | if (i_size >= e->d_size) | |
1422 | return 0; | |
1423 | /* Read the LEB */ | |
d304820a | 1424 | err = ubifs_leb_read(c, lnum, c->sbuf, 0, c->leb_size, 1); |
1e51764a AB |
1425 | if (err) |
1426 | goto out; | |
1427 | /* Change the size field and recalculate the CRC */ | |
1428 | ino = c->sbuf + offs; | |
1429 | ino->size = cpu_to_le64(e->d_size); | |
1430 | len = le32_to_cpu(ino->ch.len); | |
1431 | crc = crc32(UBIFS_CRC32_INIT, (void *)ino + 8, len - 8); | |
1432 | ino->ch.crc = cpu_to_le32(crc); | |
1433 | /* Work out where data in the LEB ends and free space begins */ | |
1434 | p = c->sbuf; | |
1435 | len = c->leb_size - 1; | |
1436 | while (p[len] == 0xff) | |
1437 | len -= 1; | |
1438 | len = ALIGN(len + 1, c->min_io_size); | |
1439 | /* Atomically write the fixed LEB back again */ | |
b36a261e | 1440 | err = ubifs_leb_change(c, lnum, c->sbuf, len); |
1e51764a AB |
1441 | if (err) |
1442 | goto out; | |
69f8a75a | 1443 | dbg_rcvry("inode %lu at %d:%d size %lld -> %lld", |
e84461ad | 1444 | (unsigned long)e->inum, lnum, offs, i_size, e->d_size); |
1e51764a AB |
1445 | return 0; |
1446 | ||
1447 | out: | |
235c362b | 1448 | ubifs_warn(c, "inode %lu failed to fix size %lld -> %lld error %d", |
e84461ad | 1449 | (unsigned long)e->inum, e->i_size, e->d_size, err); |
1e51764a AB |
1450 | return err; |
1451 | } | |
1452 | ||
1e76592f SH |
1453 | /** |
1454 | * inode_fix_size - fix inode size | |
1455 | * @c: UBIFS file-system description object | |
1456 | * @e: inode size information for recovery | |
1457 | */ | |
1458 | static int inode_fix_size(struct ubifs_info *c, struct size_entry *e) | |
1459 | { | |
1460 | struct inode *inode; | |
1461 | struct ubifs_inode *ui; | |
1462 | int err; | |
1463 | ||
1464 | if (c->ro_mount) | |
1465 | ubifs_assert(c, !e->inode); | |
1466 | ||
1467 | if (e->inode) { | |
1468 | /* Remounting rw, pick up inode we stored earlier */ | |
1469 | inode = e->inode; | |
1470 | } else { | |
1471 | inode = ubifs_iget(c->vfs_sb, e->inum); | |
1472 | if (IS_ERR(inode)) | |
1473 | return PTR_ERR(inode); | |
1474 | ||
1475 | if (inode->i_size >= e->d_size) { | |
1476 | /* | |
1477 | * The original inode in the index already has a size | |
1478 | * big enough, nothing to do | |
1479 | */ | |
1480 | iput(inode); | |
1481 | return 0; | |
1482 | } | |
1483 | ||
1484 | dbg_rcvry("ino %lu size %lld -> %lld", | |
1485 | (unsigned long)e->inum, | |
1486 | inode->i_size, e->d_size); | |
1487 | ||
1488 | ui = ubifs_inode(inode); | |
1489 | ||
1490 | inode->i_size = e->d_size; | |
1491 | ui->ui_size = e->d_size; | |
1492 | ui->synced_i_size = e->d_size; | |
1493 | ||
1494 | e->inode = inode; | |
1495 | } | |
1496 | ||
1497 | /* | |
1498 | * In readonly mode just keep the inode pinned in memory until we go | |
1499 | * readwrite. In readwrite mode write the inode to the journal with the | |
1500 | * fixed size. | |
1501 | */ | |
1502 | if (c->ro_mount) | |
1503 | return 0; | |
1504 | ||
1505 | err = ubifs_jnl_write_inode(c, inode); | |
1506 | ||
1507 | iput(inode); | |
1508 | ||
1509 | if (err) | |
1510 | return err; | |
1511 | ||
1512 | rb_erase(&e->rb, &c->size_tree); | |
1513 | kfree(e); | |
1514 | ||
1515 | return 0; | |
1516 | } | |
1517 | ||
1e51764a AB |
1518 | /** |
1519 | * ubifs_recover_size - recover inode size. | |
1520 | * @c: UBIFS file-system description object | |
1e76592f | 1521 | * @in_place: If true, do a in-place size fixup |
1e51764a AB |
1522 | * |
1523 | * This function attempts to fix inode size discrepancies identified by the | |
1524 | * 'ubifs_recover_size_accum()' function. | |
1525 | * | |
1526 | * This functions returns %0 on success and a negative error code on failure. | |
1527 | */ | |
1e76592f | 1528 | int ubifs_recover_size(struct ubifs_info *c, bool in_place) |
1e51764a AB |
1529 | { |
1530 | struct rb_node *this = rb_first(&c->size_tree); | |
1531 | ||
1532 | while (this) { | |
1533 | struct size_entry *e; | |
1534 | int err; | |
1535 | ||
1536 | e = rb_entry(this, struct size_entry, rb); | |
1e76592f SH |
1537 | |
1538 | this = rb_next(this); | |
1539 | ||
1e51764a AB |
1540 | if (!e->exists) { |
1541 | union ubifs_key key; | |
1542 | ||
1543 | ino_key_init(c, &key, e->inum); | |
1544 | err = ubifs_tnc_lookup(c, &key, c->sbuf); | |
1545 | if (err && err != -ENOENT) | |
1546 | return err; | |
1547 | if (err == -ENOENT) { | |
1548 | /* Remove data nodes that have no inode */ | |
e84461ad AB |
1549 | dbg_rcvry("removing ino %lu", |
1550 | (unsigned long)e->inum); | |
1e51764a AB |
1551 | err = ubifs_tnc_remove_ino(c, e->inum); |
1552 | if (err) | |
1553 | return err; | |
1554 | } else { | |
1555 | struct ubifs_ino_node *ino = c->sbuf; | |
1556 | ||
1557 | e->exists = 1; | |
1558 | e->i_size = le64_to_cpu(ino->size); | |
1559 | } | |
1560 | } | |
69f8a75a | 1561 | |
1e51764a | 1562 | if (e->exists && e->i_size < e->d_size) { |
1e76592f SH |
1563 | ubifs_assert(c, !(c->ro_mount && in_place)); |
1564 | ||
1565 | /* | |
1566 | * We found data that is outside the found inode size, | |
1567 | * fixup the inode size | |
1568 | */ | |
1569 | ||
1570 | if (in_place) { | |
1e51764a AB |
1571 | err = fix_size_in_place(c, e); |
1572 | if (err) | |
1573 | return err; | |
54bcfdf1 | 1574 | iput(e->inode); |
1e76592f SH |
1575 | } else { |
1576 | err = inode_fix_size(c, e); | |
1577 | if (err) | |
1578 | return err; | |
1579 | continue; | |
1e51764a AB |
1580 | } |
1581 | } | |
69f8a75a | 1582 | |
1e51764a AB |
1583 | rb_erase(&e->rb, &c->size_tree); |
1584 | kfree(e); | |
1585 | } | |
69f8a75a | 1586 | |
1e51764a AB |
1587 | return 0; |
1588 | } |