]>
Commit | Line | Data |
---|---|---|
1e51764a AB |
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: Adrian Hunter | |
20 | * Artem Bityutskiy (Битюцкий Артём) | |
21 | */ | |
22 | ||
23 | /* | |
24 | * This file implements functions needed to recover from unclean un-mounts. | |
25 | * When UBIFS is mounted, it checks a flag on the master node to determine if | |
af901ca1 | 26 | * an un-mount was completed successfully. If not, the process of mounting |
6fb4374f | 27 | * incorporates additional checking and fixing of on-flash data structures. |
1e51764a AB |
28 | * UBIFS always cleans away all remnants of an unclean un-mount, so that |
29 | * errors do not accumulate. However UBIFS defers recovery if it is mounted | |
30 | * read-only, and the flash is not modified in that case. | |
be7b42a5 AB |
31 | * |
32 | * The general UBIFS approach to the recovery is that it recovers from | |
33 | * corruptions which could be caused by power cuts, but it refuses to recover | |
34 | * from corruption caused by other reasons. And UBIFS tries to distinguish | |
35 | * between these 2 reasons of corruptions and silently recover in the former | |
36 | * case and loudly complain in the latter case. | |
37 | * | |
38 | * UBIFS writes only to erased LEBs, so it writes only to the flash space | |
39 | * containing only 0xFFs. UBIFS also always writes strictly from the beginning | |
40 | * of the LEB to the end. And UBIFS assumes that the underlying flash media | |
2765df7d | 41 | * writes in @c->max_write_size bytes at a time. |
be7b42a5 AB |
42 | * |
43 | * Hence, if UBIFS finds a corrupted node at offset X, it expects only the min. | |
44 | * I/O unit corresponding to offset X to contain corrupted data, all the | |
45 | * following min. I/O units have to contain empty space (all 0xFFs). If this is | |
46 | * not true, the corruption cannot be the result of a power cut, and UBIFS | |
47 | * refuses to mount. | |
1e51764a AB |
48 | */ |
49 | ||
50 | #include <linux/crc32.h> | |
5a0e3ad6 | 51 | #include <linux/slab.h> |
1e51764a AB |
52 | #include "ubifs.h" |
53 | ||
54 | /** | |
55 | * is_empty - determine whether a buffer is empty (contains all 0xff). | |
56 | * @buf: buffer to clean | |
57 | * @len: length of buffer | |
58 | * | |
59 | * This function returns %1 if the buffer is empty (contains all 0xff) otherwise | |
60 | * %0 is returned. | |
61 | */ | |
62 | static int is_empty(void *buf, int len) | |
63 | { | |
64 | uint8_t *p = buf; | |
65 | int i; | |
66 | ||
67 | for (i = 0; i < len; i++) | |
68 | if (*p++ != 0xff) | |
69 | return 0; | |
70 | return 1; | |
71 | } | |
72 | ||
06112547 AB |
73 | /** |
74 | * first_non_ff - find offset of the first non-0xff byte. | |
75 | * @buf: buffer to search in | |
76 | * @len: length of buffer | |
77 | * | |
78 | * This function returns offset of the first non-0xff byte in @buf or %-1 if | |
79 | * the buffer contains only 0xff bytes. | |
80 | */ | |
81 | static int first_non_ff(void *buf, int len) | |
82 | { | |
83 | uint8_t *p = buf; | |
84 | int i; | |
85 | ||
86 | for (i = 0; i < len; i++) | |
87 | if (*p++ != 0xff) | |
88 | return i; | |
89 | return -1; | |
90 | } | |
91 | ||
1e51764a AB |
92 | /** |
93 | * get_master_node - get the last valid master node allowing for corruption. | |
94 | * @c: UBIFS file-system description object | |
95 | * @lnum: LEB number | |
96 | * @pbuf: buffer containing the LEB read, is returned here | |
97 | * @mst: master node, if found, is returned here | |
98 | * @cor: corruption, if found, is returned here | |
99 | * | |
100 | * This function allocates a buffer, reads the LEB into it, and finds and | |
101 | * returns the last valid master node allowing for one area of corruption. | |
102 | * The corrupt area, if there is one, must be consistent with the assumption | |
103 | * that it is the result of an unclean unmount while the master node was being | |
104 | * written. Under those circumstances, it is valid to use the previously written | |
105 | * master node. | |
106 | * | |
107 | * This function returns %0 on success and a negative error code on failure. | |
108 | */ | |
109 | static int get_master_node(const struct ubifs_info *c, int lnum, void **pbuf, | |
110 | struct ubifs_mst_node **mst, void **cor) | |
111 | { | |
112 | const int sz = c->mst_node_alsz; | |
113 | int err, offs, len; | |
114 | void *sbuf, *buf; | |
115 | ||
116 | sbuf = vmalloc(c->leb_size); | |
117 | if (!sbuf) | |
118 | return -ENOMEM; | |
119 | ||
120 | err = ubi_read(c->ubi, lnum, sbuf, 0, c->leb_size); | |
121 | if (err && err != -EBADMSG) | |
122 | goto out_free; | |
123 | ||
124 | /* Find the first position that is definitely not a node */ | |
125 | offs = 0; | |
126 | buf = sbuf; | |
127 | len = c->leb_size; | |
128 | while (offs + UBIFS_MST_NODE_SZ <= c->leb_size) { | |
129 | struct ubifs_ch *ch = buf; | |
130 | ||
131 | if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC) | |
132 | break; | |
133 | offs += sz; | |
134 | buf += sz; | |
135 | len -= sz; | |
136 | } | |
137 | /* See if there was a valid master node before that */ | |
138 | if (offs) { | |
139 | int ret; | |
140 | ||
141 | offs -= sz; | |
142 | buf -= sz; | |
143 | len += sz; | |
144 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1); | |
145 | if (ret != SCANNED_A_NODE && offs) { | |
146 | /* Could have been corruption so check one place back */ | |
147 | offs -= sz; | |
148 | buf -= sz; | |
149 | len += sz; | |
150 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1); | |
151 | if (ret != SCANNED_A_NODE) | |
152 | /* | |
153 | * We accept only one area of corruption because | |
154 | * we are assuming that it was caused while | |
155 | * trying to write a master node. | |
156 | */ | |
157 | goto out_err; | |
158 | } | |
159 | if (ret == SCANNED_A_NODE) { | |
160 | struct ubifs_ch *ch = buf; | |
161 | ||
162 | if (ch->node_type != UBIFS_MST_NODE) | |
163 | goto out_err; | |
164 | dbg_rcvry("found a master node at %d:%d", lnum, offs); | |
165 | *mst = buf; | |
166 | offs += sz; | |
167 | buf += sz; | |
168 | len -= sz; | |
169 | } | |
170 | } | |
171 | /* Check for corruption */ | |
172 | if (offs < c->leb_size) { | |
173 | if (!is_empty(buf, min_t(int, len, sz))) { | |
174 | *cor = buf; | |
175 | dbg_rcvry("found corruption at %d:%d", lnum, offs); | |
176 | } | |
177 | offs += sz; | |
178 | buf += sz; | |
179 | len -= sz; | |
180 | } | |
181 | /* Check remaining empty space */ | |
182 | if (offs < c->leb_size) | |
183 | if (!is_empty(buf, len)) | |
184 | goto out_err; | |
185 | *pbuf = sbuf; | |
186 | return 0; | |
187 | ||
188 | out_err: | |
189 | err = -EINVAL; | |
190 | out_free: | |
191 | vfree(sbuf); | |
192 | *mst = NULL; | |
193 | *cor = NULL; | |
194 | return err; | |
195 | } | |
196 | ||
197 | /** | |
198 | * write_rcvrd_mst_node - write recovered master node. | |
199 | * @c: UBIFS file-system description object | |
200 | * @mst: master node | |
201 | * | |
202 | * This function returns %0 on success and a negative error code on failure. | |
203 | */ | |
204 | static int write_rcvrd_mst_node(struct ubifs_info *c, | |
205 | struct ubifs_mst_node *mst) | |
206 | { | |
207 | int err = 0, lnum = UBIFS_MST_LNUM, sz = c->mst_node_alsz; | |
0ecb9529 | 208 | __le32 save_flags; |
1e51764a AB |
209 | |
210 | dbg_rcvry("recovery"); | |
211 | ||
212 | save_flags = mst->flags; | |
0ecb9529 | 213 | mst->flags |= cpu_to_le32(UBIFS_MST_RCVRY); |
1e51764a AB |
214 | |
215 | ubifs_prepare_node(c, mst, UBIFS_MST_NODE_SZ, 1); | |
216 | err = ubi_leb_change(c->ubi, lnum, mst, sz, UBI_SHORTTERM); | |
217 | if (err) | |
218 | goto out; | |
219 | err = ubi_leb_change(c->ubi, lnum + 1, mst, sz, UBI_SHORTTERM); | |
220 | if (err) | |
221 | goto out; | |
222 | out: | |
223 | mst->flags = save_flags; | |
224 | return err; | |
225 | } | |
226 | ||
227 | /** | |
228 | * ubifs_recover_master_node - recover the master node. | |
229 | * @c: UBIFS file-system description object | |
230 | * | |
231 | * This function recovers the master node from corruption that may occur due to | |
232 | * an unclean unmount. | |
233 | * | |
234 | * This function returns %0 on success and a negative error code on failure. | |
235 | */ | |
236 | int ubifs_recover_master_node(struct ubifs_info *c) | |
237 | { | |
238 | void *buf1 = NULL, *buf2 = NULL, *cor1 = NULL, *cor2 = NULL; | |
239 | struct ubifs_mst_node *mst1 = NULL, *mst2 = NULL, *mst; | |
240 | const int sz = c->mst_node_alsz; | |
241 | int err, offs1, offs2; | |
242 | ||
243 | dbg_rcvry("recovery"); | |
244 | ||
245 | err = get_master_node(c, UBIFS_MST_LNUM, &buf1, &mst1, &cor1); | |
246 | if (err) | |
247 | goto out_free; | |
248 | ||
249 | err = get_master_node(c, UBIFS_MST_LNUM + 1, &buf2, &mst2, &cor2); | |
250 | if (err) | |
251 | goto out_free; | |
252 | ||
253 | if (mst1) { | |
254 | offs1 = (void *)mst1 - buf1; | |
255 | if ((le32_to_cpu(mst1->flags) & UBIFS_MST_RCVRY) && | |
256 | (offs1 == 0 && !cor1)) { | |
257 | /* | |
258 | * mst1 was written by recovery at offset 0 with no | |
259 | * corruption. | |
260 | */ | |
261 | dbg_rcvry("recovery recovery"); | |
262 | mst = mst1; | |
263 | } else if (mst2) { | |
264 | offs2 = (void *)mst2 - buf2; | |
265 | if (offs1 == offs2) { | |
266 | /* Same offset, so must be the same */ | |
267 | if (memcmp((void *)mst1 + UBIFS_CH_SZ, | |
268 | (void *)mst2 + UBIFS_CH_SZ, | |
269 | UBIFS_MST_NODE_SZ - UBIFS_CH_SZ)) | |
270 | goto out_err; | |
271 | mst = mst1; | |
272 | } else if (offs2 + sz == offs1) { | |
273 | /* 1st LEB was written, 2nd was not */ | |
274 | if (cor1) | |
275 | goto out_err; | |
276 | mst = mst1; | |
277 | } else if (offs1 == 0 && offs2 + sz >= c->leb_size) { | |
278 | /* 1st LEB was unmapped and written, 2nd not */ | |
279 | if (cor1) | |
280 | goto out_err; | |
281 | mst = mst1; | |
282 | } else | |
283 | goto out_err; | |
284 | } else { | |
285 | /* | |
286 | * 2nd LEB was unmapped and about to be written, so | |
287 | * there must be only one master node in the first LEB | |
288 | * and no corruption. | |
289 | */ | |
290 | if (offs1 != 0 || cor1) | |
291 | goto out_err; | |
292 | mst = mst1; | |
293 | } | |
294 | } else { | |
295 | if (!mst2) | |
296 | goto out_err; | |
297 | /* | |
298 | * 1st LEB was unmapped and about to be written, so there must | |
299 | * be no room left in 2nd LEB. | |
300 | */ | |
301 | offs2 = (void *)mst2 - buf2; | |
302 | if (offs2 + sz + sz <= c->leb_size) | |
303 | goto out_err; | |
304 | mst = mst2; | |
305 | } | |
306 | ||
348709ba | 307 | ubifs_msg("recovered master node from LEB %d", |
1e51764a AB |
308 | (mst == mst1 ? UBIFS_MST_LNUM : UBIFS_MST_LNUM + 1)); |
309 | ||
310 | memcpy(c->mst_node, mst, UBIFS_MST_NODE_SZ); | |
311 | ||
2ef13294 | 312 | if (c->ro_mount) { |
1e51764a AB |
313 | /* Read-only mode. Keep a copy for switching to rw mode */ |
314 | c->rcvrd_mst_node = kmalloc(sz, GFP_KERNEL); | |
315 | if (!c->rcvrd_mst_node) { | |
316 | err = -ENOMEM; | |
317 | goto out_free; | |
318 | } | |
319 | memcpy(c->rcvrd_mst_node, c->mst_node, UBIFS_MST_NODE_SZ); | |
6e0d9fd3 AB |
320 | |
321 | /* | |
322 | * We had to recover the master node, which means there was an | |
323 | * unclean reboot. However, it is possible that the master node | |
324 | * is clean at this point, i.e., %UBIFS_MST_DIRTY is not set. | |
325 | * E.g., consider the following chain of events: | |
326 | * | |
327 | * 1. UBIFS was cleanly unmounted, so the master node is clean | |
328 | * 2. UBIFS is being mounted R/W and starts changing the master | |
329 | * node in the first (%UBIFS_MST_LNUM). A power cut happens, | |
330 | * so this LEB ends up with some amount of garbage at the | |
331 | * end. | |
332 | * 3. UBIFS is being mounted R/O. We reach this place and | |
333 | * recover the master node from the second LEB | |
334 | * (%UBIFS_MST_LNUM + 1). But we cannot update the media | |
335 | * because we are being mounted R/O. We have to defer the | |
336 | * operation. | |
337 | * 4. However, this master node (@c->mst_node) is marked as | |
338 | * clean (since the step 1). And if we just return, the | |
339 | * mount code will be confused and won't recover the master | |
340 | * node when it is re-mounter R/W later. | |
341 | * | |
342 | * Thus, to force the recovery by marking the master node as | |
343 | * dirty. | |
344 | */ | |
345 | c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY); | |
1e51764a AB |
346 | } else { |
347 | /* Write the recovered master node */ | |
348 | c->max_sqnum = le64_to_cpu(mst->ch.sqnum) - 1; | |
349 | err = write_rcvrd_mst_node(c, c->mst_node); | |
350 | if (err) | |
351 | goto out_free; | |
352 | } | |
353 | ||
354 | vfree(buf2); | |
355 | vfree(buf1); | |
356 | ||
357 | return 0; | |
358 | ||
359 | out_err: | |
360 | err = -EINVAL; | |
361 | out_free: | |
362 | ubifs_err("failed to recover master node"); | |
363 | if (mst1) { | |
364 | dbg_err("dumping first master node"); | |
365 | dbg_dump_node(c, mst1); | |
366 | } | |
367 | if (mst2) { | |
368 | dbg_err("dumping second master node"); | |
369 | dbg_dump_node(c, mst2); | |
370 | } | |
371 | vfree(buf2); | |
372 | vfree(buf1); | |
373 | return err; | |
374 | } | |
375 | ||
376 | /** | |
377 | * ubifs_write_rcvrd_mst_node - write the recovered master node. | |
378 | * @c: UBIFS file-system description object | |
379 | * | |
380 | * This function writes the master node that was recovered during mounting in | |
381 | * read-only mode and must now be written because we are remounting rw. | |
382 | * | |
383 | * This function returns %0 on success and a negative error code on failure. | |
384 | */ | |
385 | int ubifs_write_rcvrd_mst_node(struct ubifs_info *c) | |
386 | { | |
387 | int err; | |
388 | ||
389 | if (!c->rcvrd_mst_node) | |
390 | return 0; | |
391 | c->rcvrd_mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY); | |
392 | c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY); | |
393 | err = write_rcvrd_mst_node(c, c->rcvrd_mst_node); | |
394 | if (err) | |
395 | return err; | |
396 | kfree(c->rcvrd_mst_node); | |
397 | c->rcvrd_mst_node = NULL; | |
398 | return 0; | |
399 | } | |
400 | ||
401 | /** | |
402 | * is_last_write - determine if an offset was in the last write to a LEB. | |
403 | * @c: UBIFS file-system description object | |
404 | * @buf: buffer to check | |
405 | * @offs: offset to check | |
406 | * | |
407 | * This function returns %1 if @offs was in the last write to the LEB whose data | |
2765df7d AB |
408 | * is in @buf, otherwise %0 is returned. The determination is made by checking |
409 | * for subsequent empty space starting from the next @c->max_write_size | |
410 | * boundary. | |
1e51764a AB |
411 | */ |
412 | static int is_last_write(const struct ubifs_info *c, void *buf, int offs) | |
413 | { | |
428ff9d2 | 414 | int empty_offs, check_len; |
1e51764a AB |
415 | uint8_t *p; |
416 | ||
1e51764a | 417 | /* |
2765df7d AB |
418 | * Round up to the next @c->max_write_size boundary i.e. @offs is in |
419 | * the last wbuf written. After that should be empty space. | |
1e51764a | 420 | */ |
2765df7d | 421 | empty_offs = ALIGN(offs + 1, c->max_write_size); |
1e51764a AB |
422 | check_len = c->leb_size - empty_offs; |
423 | p = buf + empty_offs - offs; | |
431102fe | 424 | return is_empty(p, check_len); |
1e51764a AB |
425 | } |
426 | ||
427 | /** | |
428 | * clean_buf - clean the data from an LEB sitting in a buffer. | |
429 | * @c: UBIFS file-system description object | |
430 | * @buf: buffer to clean | |
431 | * @lnum: LEB number to clean | |
432 | * @offs: offset from which to clean | |
433 | * @len: length of buffer | |
434 | * | |
435 | * This function pads up to the next min_io_size boundary (if there is one) and | |
436 | * sets empty space to all 0xff. @buf, @offs and @len are updated to the next | |
428ff9d2 | 437 | * @c->min_io_size boundary. |
1e51764a AB |
438 | */ |
439 | static void clean_buf(const struct ubifs_info *c, void **buf, int lnum, | |
440 | int *offs, int *len) | |
441 | { | |
442 | int empty_offs, pad_len; | |
443 | ||
444 | lnum = lnum; | |
445 | dbg_rcvry("cleaning corruption at %d:%d", lnum, *offs); | |
446 | ||
1e51764a AB |
447 | ubifs_assert(!(*offs & 7)); |
448 | empty_offs = ALIGN(*offs, c->min_io_size); | |
449 | pad_len = empty_offs - *offs; | |
450 | ubifs_pad(c, *buf, pad_len); | |
451 | *offs += pad_len; | |
452 | *buf += pad_len; | |
453 | *len -= pad_len; | |
454 | memset(*buf, 0xff, c->leb_size - empty_offs); | |
455 | } | |
456 | ||
457 | /** | |
458 | * no_more_nodes - determine if there are no more nodes in a buffer. | |
459 | * @c: UBIFS file-system description object | |
460 | * @buf: buffer to check | |
461 | * @len: length of buffer | |
462 | * @lnum: LEB number of the LEB from which @buf was read | |
463 | * @offs: offset from which @buf was read | |
464 | * | |
de097578 AH |
465 | * This function ensures that the corrupted node at @offs is the last thing |
466 | * written to a LEB. This function returns %1 if more data is not found and | |
467 | * %0 if more data is found. | |
1e51764a AB |
468 | */ |
469 | static int no_more_nodes(const struct ubifs_info *c, void *buf, int len, | |
470 | int lnum, int offs) | |
471 | { | |
de097578 AH |
472 | struct ubifs_ch *ch = buf; |
473 | int skip, dlen = le32_to_cpu(ch->len); | |
1e51764a | 474 | |
de097578 | 475 | /* Check for empty space after the corrupt node's common header */ |
2765df7d | 476 | skip = ALIGN(offs + UBIFS_CH_SZ, c->max_write_size) - offs; |
de097578 AH |
477 | if (is_empty(buf + skip, len - skip)) |
478 | return 1; | |
479 | /* | |
480 | * The area after the common header size is not empty, so the common | |
481 | * header must be intact. Check it. | |
482 | */ | |
483 | if (ubifs_check_node(c, buf, lnum, offs, 1, 0) != -EUCLEAN) { | |
484 | dbg_rcvry("unexpected bad common header at %d:%d", lnum, offs); | |
485 | return 0; | |
1e51764a | 486 | } |
de097578 | 487 | /* Now we know the corrupt node's length we can skip over it */ |
2765df7d | 488 | skip = ALIGN(offs + dlen, c->max_write_size) - offs; |
de097578 AH |
489 | /* After which there should be empty space */ |
490 | if (is_empty(buf + skip, len - skip)) | |
491 | return 1; | |
492 | dbg_rcvry("unexpected data at %d:%d", lnum, offs + skip); | |
493 | return 0; | |
1e51764a AB |
494 | } |
495 | ||
496 | /** | |
497 | * fix_unclean_leb - fix an unclean LEB. | |
498 | * @c: UBIFS file-system description object | |
499 | * @sleb: scanned LEB information | |
500 | * @start: offset where scan started | |
501 | */ | |
502 | static int fix_unclean_leb(struct ubifs_info *c, struct ubifs_scan_leb *sleb, | |
503 | int start) | |
504 | { | |
505 | int lnum = sleb->lnum, endpt = start; | |
506 | ||
507 | /* Get the end offset of the last node we are keeping */ | |
508 | if (!list_empty(&sleb->nodes)) { | |
509 | struct ubifs_scan_node *snod; | |
510 | ||
511 | snod = list_entry(sleb->nodes.prev, | |
512 | struct ubifs_scan_node, list); | |
513 | endpt = snod->offs + snod->len; | |
514 | } | |
515 | ||
2ef13294 | 516 | if (c->ro_mount && !c->remounting_rw) { |
1e51764a AB |
517 | /* Add to recovery list */ |
518 | struct ubifs_unclean_leb *ucleb; | |
519 | ||
520 | dbg_rcvry("need to fix LEB %d start %d endpt %d", | |
521 | lnum, start, sleb->endpt); | |
522 | ucleb = kzalloc(sizeof(struct ubifs_unclean_leb), GFP_NOFS); | |
523 | if (!ucleb) | |
524 | return -ENOMEM; | |
525 | ucleb->lnum = lnum; | |
526 | ucleb->endpt = endpt; | |
527 | list_add_tail(&ucleb->list, &c->unclean_leb_list); | |
528 | } else { | |
529 | /* Write the fixed LEB back to flash */ | |
530 | int err; | |
531 | ||
532 | dbg_rcvry("fixing LEB %d start %d endpt %d", | |
533 | lnum, start, sleb->endpt); | |
534 | if (endpt == 0) { | |
535 | err = ubifs_leb_unmap(c, lnum); | |
536 | if (err) | |
537 | return err; | |
538 | } else { | |
539 | int len = ALIGN(endpt, c->min_io_size); | |
540 | ||
541 | if (start) { | |
542 | err = ubi_read(c->ubi, lnum, sleb->buf, 0, | |
543 | start); | |
544 | if (err) | |
545 | return err; | |
546 | } | |
547 | /* Pad to min_io_size */ | |
548 | if (len > endpt) { | |
549 | int pad_len = len - ALIGN(endpt, 8); | |
550 | ||
551 | if (pad_len > 0) { | |
552 | void *buf = sleb->buf + len - pad_len; | |
553 | ||
554 | ubifs_pad(c, buf, pad_len); | |
555 | } | |
556 | } | |
557 | err = ubi_leb_change(c->ubi, lnum, sleb->buf, len, | |
558 | UBI_UNKNOWN); | |
559 | if (err) | |
560 | return err; | |
561 | } | |
562 | } | |
563 | return 0; | |
564 | } | |
565 | ||
566 | /** | |
bbf2b37a | 567 | * drop_last_node - drop the last node or group of nodes. |
1e51764a AB |
568 | * @sleb: scanned LEB information |
569 | * @offs: offset of dropped nodes is returned here | |
bbf2b37a | 570 | * @grouped: non-zero if whole group of nodes have to be dropped |
1e51764a | 571 | * |
bbf2b37a AB |
572 | * This is a helper function for 'ubifs_recover_leb()' which drops the last |
573 | * node of the scanned LEB or the last group of nodes if @grouped is not zero. | |
574 | * This function returns %1 if a node was dropped and %0 otherwise. | |
1e51764a | 575 | */ |
bbf2b37a | 576 | static int drop_last_node(struct ubifs_scan_leb *sleb, int *offs, int grouped) |
1e51764a AB |
577 | { |
578 | int dropped = 0; | |
579 | ||
580 | while (!list_empty(&sleb->nodes)) { | |
581 | struct ubifs_scan_node *snod; | |
582 | struct ubifs_ch *ch; | |
583 | ||
584 | snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, | |
585 | list); | |
586 | ch = snod->node; | |
587 | if (ch->group_type != UBIFS_IN_NODE_GROUP) | |
588 | return dropped; | |
589 | dbg_rcvry("dropping node at %d:%d", sleb->lnum, snod->offs); | |
590 | *offs = snod->offs; | |
591 | list_del(&snod->list); | |
592 | kfree(snod); | |
593 | sleb->nodes_cnt -= 1; | |
594 | dropped = 1; | |
bbf2b37a AB |
595 | if (!grouped) |
596 | break; | |
1e51764a AB |
597 | } |
598 | return dropped; | |
599 | } | |
600 | ||
601 | /** | |
602 | * ubifs_recover_leb - scan and recover a LEB. | |
603 | * @c: UBIFS file-system description object | |
604 | * @lnum: LEB number | |
605 | * @offs: offset | |
606 | * @sbuf: LEB-sized buffer to use | |
607 | * @grouped: nodes may be grouped for recovery | |
608 | * | |
609 | * This function does a scan of a LEB, but caters for errors that might have | |
610 | * been caused by the unclean unmount from which we are attempting to recover. | |
ed43f2f0 AB |
611 | * Returns %0 in case of success, %-EUCLEAN if an unrecoverable corruption is |
612 | * found, and a negative error code in case of failure. | |
1e51764a AB |
613 | */ |
614 | struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum, | |
615 | int offs, void *sbuf, int grouped) | |
616 | { | |
bbf2b37a | 617 | int ret = 0, err, len = c->leb_size - offs, start = offs, min_io_unit; |
1e51764a AB |
618 | struct ubifs_scan_leb *sleb; |
619 | void *buf = sbuf + offs; | |
620 | ||
621 | dbg_rcvry("%d:%d", lnum, offs); | |
622 | ||
623 | sleb = ubifs_start_scan(c, lnum, offs, sbuf); | |
624 | if (IS_ERR(sleb)) | |
625 | return sleb; | |
626 | ||
bbf2b37a | 627 | ubifs_assert(len >= 8); |
1e51764a | 628 | while (len >= 8) { |
1e51764a AB |
629 | dbg_scan("look at LEB %d:%d (%d bytes left)", |
630 | lnum, offs, len); | |
631 | ||
632 | cond_resched(); | |
633 | ||
634 | /* | |
635 | * Scan quietly until there is an error from which we cannot | |
636 | * recover | |
637 | */ | |
61799206 | 638 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 0); |
1e51764a AB |
639 | if (ret == SCANNED_A_NODE) { |
640 | /* A valid node, and not a padding node */ | |
641 | struct ubifs_ch *ch = buf; | |
642 | int node_len; | |
643 | ||
644 | err = ubifs_add_snod(c, sleb, buf, offs); | |
645 | if (err) | |
646 | goto error; | |
647 | node_len = ALIGN(le32_to_cpu(ch->len), 8); | |
648 | offs += node_len; | |
649 | buf += node_len; | |
650 | len -= node_len; | |
61799206 | 651 | } else if (ret > 0) { |
1e51764a AB |
652 | /* Padding bytes or a valid padding node */ |
653 | offs += ret; | |
654 | buf += ret; | |
655 | len -= ret; | |
61799206 AB |
656 | } else if (ret == SCANNED_EMPTY_SPACE || |
657 | ret == SCANNED_GARBAGE || | |
658 | ret == SCANNED_A_BAD_PAD_NODE || | |
659 | ret == SCANNED_A_CORRUPT_NODE) { | |
660 | dbg_rcvry("found corruption - %d", ret); | |
1e51764a | 661 | break; |
61799206 AB |
662 | } else { |
663 | dbg_err("unexpected return value %d", ret); | |
ed43f2f0 AB |
664 | err = -EINVAL; |
665 | goto error; | |
1e51764a AB |
666 | } |
667 | } | |
668 | ||
61799206 | 669 | if (ret == SCANNED_GARBAGE || ret == SCANNED_A_BAD_PAD_NODE) { |
43e07073 | 670 | if (!is_last_write(c, buf, offs)) |
61799206 AB |
671 | goto corrupted_rescan; |
672 | } else if (ret == SCANNED_A_CORRUPT_NODE) { | |
43e07073 | 673 | if (!no_more_nodes(c, buf, len, lnum, offs)) |
61799206 AB |
674 | goto corrupted_rescan; |
675 | } else if (!is_empty(buf, len)) { | |
43e07073 | 676 | if (!is_last_write(c, buf, offs)) { |
06112547 AB |
677 | int corruption = first_non_ff(buf, len); |
678 | ||
be7b42a5 AB |
679 | /* |
680 | * See header comment for this file for more | |
681 | * explanations about the reasons we have this check. | |
682 | */ | |
06112547 AB |
683 | ubifs_err("corrupt empty space LEB %d:%d, corruption " |
684 | "starts at %d", lnum, offs, corruption); | |
685 | /* Make sure we dump interesting non-0xFF data */ | |
10ac2797 | 686 | offs += corruption; |
06112547 | 687 | buf += corruption; |
1e51764a AB |
688 | goto corrupted; |
689 | } | |
690 | } | |
691 | ||
bbf2b37a AB |
692 | min_io_unit = round_down(offs, c->min_io_size); |
693 | if (grouped) | |
694 | /* | |
695 | * If nodes are grouped, always drop the incomplete group at | |
696 | * the end. | |
697 | */ | |
698 | drop_last_node(sleb, &offs, 1); | |
699 | ||
700 | /* | |
701 | * While we are in the middle of the same min. I/O unit keep dropping | |
702 | * nodes. So basically, what we want is to make sure that the last min. | |
703 | * I/O unit where we saw the corruption is dropped completely with all | |
704 | * the uncorrupted node which may possibly sit there. | |
705 | * | |
706 | * In other words, let's name the min. I/O unit where the corruption | |
707 | * starts B, and the previous min. I/O unit A. The below code tries to | |
708 | * deal with a situation when half of B contains valid nodes or the end | |
709 | * of a valid node, and the second half of B contains corrupted data or | |
710 | * garbage. This means that UBIFS had been writing to B just before the | |
711 | * power cut happened. I do not know how realistic is this scenario | |
712 | * that half of the min. I/O unit had been written successfully and the | |
713 | * other half not, but this is possible in our 'failure mode emulation' | |
714 | * infrastructure at least. | |
715 | * | |
716 | * So what is the problem, why we need to drop those nodes? Whey can't | |
717 | * we just clean-up the second half of B by putting a padding node | |
718 | * there? We can, and this works fine with one exception which was | |
719 | * reproduced with power cut emulation testing and happens extremely | |
720 | * rarely. The description follows, but it is worth noting that that is | |
721 | * only about the GC head, so we could do this trick only if the bud | |
722 | * belongs to the GC head, but it does not seem to be worth an | |
723 | * additional "if" statement. | |
724 | * | |
725 | * So, imagine the file-system is full, we run GC which is moving valid | |
726 | * nodes from LEB X to LEB Y (obviously, LEB Y is the current GC head | |
727 | * LEB). The @c->gc_lnum is -1, which means that GC will retain LEB X | |
728 | * and will try to continue. Imagine that LEB X is currently the | |
729 | * dirtiest LEB, and the amount of used space in LEB Y is exactly the | |
730 | * same as amount of free space in LEB X. | |
731 | * | |
732 | * And a power cut happens when nodes are moved from LEB X to LEB Y. We | |
733 | * are here trying to recover LEB Y which is the GC head LEB. We find | |
734 | * the min. I/O unit B as described above. Then we clean-up LEB Y by | |
735 | * padding min. I/O unit. And later 'ubifs_rcvry_gc_commit()' function | |
736 | * fails, because it cannot find a dirty LEB which could be GC'd into | |
737 | * LEB Y! Even LEB X does not match because the amount of valid nodes | |
738 | * there does not fit the free space in LEB Y any more! And this is | |
739 | * because of the padding node which we added to LEB Y. The | |
740 | * user-visible effect of this which I once observed and analysed is | |
741 | * that we cannot mount the file-system with -ENOSPC error. | |
742 | * | |
743 | * So obviously, to make sure that situation does not happen we should | |
744 | * free min. I/O unit B in LEB Y completely and the last used min. I/O | |
745 | * unit in LEB Y should be A. This is basically what the below code | |
746 | * tries to do. | |
747 | */ | |
748 | while (min_io_unit == round_down(offs, c->min_io_size) && | |
749 | min_io_unit != offs && | |
750 | drop_last_node(sleb, &offs, grouped)); | |
751 | ||
752 | buf = sbuf + offs; | |
753 | len = c->leb_size - offs; | |
1e51764a | 754 | |
43e07073 | 755 | clean_buf(c, &buf, lnum, &offs, &len); |
1e51764a AB |
756 | ubifs_end_scan(c, sleb, lnum, offs); |
757 | ||
7c47bfd0 AB |
758 | err = fix_unclean_leb(c, sleb, start); |
759 | if (err) | |
760 | goto error; | |
1e51764a AB |
761 | |
762 | return sleb; | |
763 | ||
61799206 AB |
764 | corrupted_rescan: |
765 | /* Re-scan the corrupted data with verbose messages */ | |
766 | dbg_err("corruptio %d", ret); | |
767 | ubifs_scan_a_node(c, buf, len, lnum, offs, 1); | |
1e51764a AB |
768 | corrupted: |
769 | ubifs_scanned_corruption(c, lnum, offs, buf); | |
770 | err = -EUCLEAN; | |
771 | error: | |
772 | ubifs_err("LEB %d scanning failed", lnum); | |
773 | ubifs_scan_destroy(sleb); | |
774 | return ERR_PTR(err); | |
775 | } | |
776 | ||
777 | /** | |
778 | * get_cs_sqnum - get commit start sequence number. | |
779 | * @c: UBIFS file-system description object | |
780 | * @lnum: LEB number of commit start node | |
781 | * @offs: offset of commit start node | |
782 | * @cs_sqnum: commit start sequence number is returned here | |
783 | * | |
784 | * This function returns %0 on success and a negative error code on failure. | |
785 | */ | |
786 | static int get_cs_sqnum(struct ubifs_info *c, int lnum, int offs, | |
787 | unsigned long long *cs_sqnum) | |
788 | { | |
789 | struct ubifs_cs_node *cs_node = NULL; | |
790 | int err, ret; | |
791 | ||
792 | dbg_rcvry("at %d:%d", lnum, offs); | |
793 | cs_node = kmalloc(UBIFS_CS_NODE_SZ, GFP_KERNEL); | |
794 | if (!cs_node) | |
795 | return -ENOMEM; | |
796 | if (c->leb_size - offs < UBIFS_CS_NODE_SZ) | |
797 | goto out_err; | |
798 | err = ubi_read(c->ubi, lnum, (void *)cs_node, offs, UBIFS_CS_NODE_SZ); | |
799 | if (err && err != -EBADMSG) | |
800 | goto out_free; | |
801 | ret = ubifs_scan_a_node(c, cs_node, UBIFS_CS_NODE_SZ, lnum, offs, 0); | |
802 | if (ret != SCANNED_A_NODE) { | |
803 | dbg_err("Not a valid node"); | |
804 | goto out_err; | |
805 | } | |
806 | if (cs_node->ch.node_type != UBIFS_CS_NODE) { | |
807 | dbg_err("Node a CS node, type is %d", cs_node->ch.node_type); | |
808 | goto out_err; | |
809 | } | |
810 | if (le64_to_cpu(cs_node->cmt_no) != c->cmt_no) { | |
811 | dbg_err("CS node cmt_no %llu != current cmt_no %llu", | |
812 | (unsigned long long)le64_to_cpu(cs_node->cmt_no), | |
813 | c->cmt_no); | |
814 | goto out_err; | |
815 | } | |
816 | *cs_sqnum = le64_to_cpu(cs_node->ch.sqnum); | |
817 | dbg_rcvry("commit start sqnum %llu", *cs_sqnum); | |
818 | kfree(cs_node); | |
819 | return 0; | |
820 | ||
821 | out_err: | |
822 | err = -EINVAL; | |
823 | out_free: | |
824 | ubifs_err("failed to get CS sqnum"); | |
825 | kfree(cs_node); | |
826 | return err; | |
827 | } | |
828 | ||
829 | /** | |
830 | * ubifs_recover_log_leb - scan and recover a log LEB. | |
831 | * @c: UBIFS file-system description object | |
832 | * @lnum: LEB number | |
833 | * @offs: offset | |
834 | * @sbuf: LEB-sized buffer to use | |
835 | * | |
836 | * This function does a scan of a LEB, but caters for errors that might have | |
7d08ae3c AB |
837 | * been caused by unclean reboots from which we are attempting to recover |
838 | * (assume that only the last log LEB can be corrupted by an unclean reboot). | |
1e51764a AB |
839 | * |
840 | * This function returns %0 on success and a negative error code on failure. | |
841 | */ | |
842 | struct ubifs_scan_leb *ubifs_recover_log_leb(struct ubifs_info *c, int lnum, | |
843 | int offs, void *sbuf) | |
844 | { | |
845 | struct ubifs_scan_leb *sleb; | |
846 | int next_lnum; | |
847 | ||
848 | dbg_rcvry("LEB %d", lnum); | |
849 | next_lnum = lnum + 1; | |
850 | if (next_lnum >= UBIFS_LOG_LNUM + c->log_lebs) | |
851 | next_lnum = UBIFS_LOG_LNUM; | |
852 | if (next_lnum != c->ltail_lnum) { | |
853 | /* | |
854 | * We can only recover at the end of the log, so check that the | |
855 | * next log LEB is empty or out of date. | |
856 | */ | |
348709ba | 857 | sleb = ubifs_scan(c, next_lnum, 0, sbuf, 0); |
1e51764a AB |
858 | if (IS_ERR(sleb)) |
859 | return sleb; | |
860 | if (sleb->nodes_cnt) { | |
861 | struct ubifs_scan_node *snod; | |
862 | unsigned long long cs_sqnum = c->cs_sqnum; | |
863 | ||
864 | snod = list_entry(sleb->nodes.next, | |
865 | struct ubifs_scan_node, list); | |
866 | if (cs_sqnum == 0) { | |
867 | int err; | |
868 | ||
869 | err = get_cs_sqnum(c, lnum, offs, &cs_sqnum); | |
870 | if (err) { | |
871 | ubifs_scan_destroy(sleb); | |
872 | return ERR_PTR(err); | |
873 | } | |
874 | } | |
875 | if (snod->sqnum > cs_sqnum) { | |
876 | ubifs_err("unrecoverable log corruption " | |
877 | "in LEB %d", lnum); | |
878 | ubifs_scan_destroy(sleb); | |
879 | return ERR_PTR(-EUCLEAN); | |
880 | } | |
881 | } | |
882 | ubifs_scan_destroy(sleb); | |
883 | } | |
884 | return ubifs_recover_leb(c, lnum, offs, sbuf, 0); | |
885 | } | |
886 | ||
887 | /** | |
888 | * recover_head - recover a head. | |
889 | * @c: UBIFS file-system description object | |
890 | * @lnum: LEB number of head to recover | |
891 | * @offs: offset of head to recover | |
892 | * @sbuf: LEB-sized buffer to use | |
893 | * | |
894 | * This function ensures that there is no data on the flash at a head location. | |
895 | * | |
896 | * This function returns %0 on success and a negative error code on failure. | |
897 | */ | |
898 | static int recover_head(const struct ubifs_info *c, int lnum, int offs, | |
899 | void *sbuf) | |
900 | { | |
2765df7d | 901 | int len = c->max_write_size, err; |
1e51764a | 902 | |
1e51764a AB |
903 | if (offs + len > c->leb_size) |
904 | len = c->leb_size - offs; | |
905 | ||
906 | if (!len) | |
907 | return 0; | |
908 | ||
909 | /* Read at the head location and check it is empty flash */ | |
910 | err = ubi_read(c->ubi, lnum, sbuf, offs, len); | |
431102fe | 911 | if (err || !is_empty(sbuf, len)) { |
1e51764a AB |
912 | dbg_rcvry("cleaning head at %d:%d", lnum, offs); |
913 | if (offs == 0) | |
914 | return ubifs_leb_unmap(c, lnum); | |
915 | err = ubi_read(c->ubi, lnum, sbuf, 0, offs); | |
916 | if (err) | |
917 | return err; | |
918 | return ubi_leb_change(c->ubi, lnum, sbuf, offs, UBI_UNKNOWN); | |
919 | } | |
920 | ||
921 | return 0; | |
922 | } | |
923 | ||
924 | /** | |
925 | * ubifs_recover_inl_heads - recover index and LPT heads. | |
926 | * @c: UBIFS file-system description object | |
927 | * @sbuf: LEB-sized buffer to use | |
928 | * | |
929 | * This function ensures that there is no data on the flash at the index and | |
930 | * LPT head locations. | |
931 | * | |
932 | * This deals with the recovery of a half-completed journal commit. UBIFS is | |
933 | * careful never to overwrite the last version of the index or the LPT. Because | |
934 | * the index and LPT are wandering trees, data from a half-completed commit will | |
935 | * not be referenced anywhere in UBIFS. The data will be either in LEBs that are | |
936 | * assumed to be empty and will be unmapped anyway before use, or in the index | |
937 | * and LPT heads. | |
938 | * | |
939 | * This function returns %0 on success and a negative error code on failure. | |
940 | */ | |
941 | int ubifs_recover_inl_heads(const struct ubifs_info *c, void *sbuf) | |
942 | { | |
943 | int err; | |
944 | ||
2ef13294 | 945 | ubifs_assert(!c->ro_mount || c->remounting_rw); |
1e51764a AB |
946 | |
947 | dbg_rcvry("checking index head at %d:%d", c->ihead_lnum, c->ihead_offs); | |
948 | err = recover_head(c, c->ihead_lnum, c->ihead_offs, sbuf); | |
949 | if (err) | |
950 | return err; | |
951 | ||
952 | dbg_rcvry("checking LPT head at %d:%d", c->nhead_lnum, c->nhead_offs); | |
953 | err = recover_head(c, c->nhead_lnum, c->nhead_offs, sbuf); | |
954 | if (err) | |
955 | return err; | |
956 | ||
957 | return 0; | |
958 | } | |
959 | ||
960 | /** | |
961 | * clean_an_unclean_leb - read and write a LEB to remove corruption. | |
962 | * @c: UBIFS file-system description object | |
963 | * @ucleb: unclean LEB information | |
964 | * @sbuf: LEB-sized buffer to use | |
965 | * | |
966 | * This function reads a LEB up to a point pre-determined by the mount recovery, | |
967 | * checks the nodes, and writes the result back to the flash, thereby cleaning | |
968 | * off any following corruption, or non-fatal ECC errors. | |
969 | * | |
970 | * This function returns %0 on success and a negative error code on failure. | |
971 | */ | |
972 | static int clean_an_unclean_leb(const struct ubifs_info *c, | |
973 | struct ubifs_unclean_leb *ucleb, void *sbuf) | |
974 | { | |
975 | int err, lnum = ucleb->lnum, offs = 0, len = ucleb->endpt, quiet = 1; | |
976 | void *buf = sbuf; | |
977 | ||
978 | dbg_rcvry("LEB %d len %d", lnum, len); | |
979 | ||
980 | if (len == 0) { | |
981 | /* Nothing to read, just unmap it */ | |
982 | err = ubifs_leb_unmap(c, lnum); | |
983 | if (err) | |
984 | return err; | |
985 | return 0; | |
986 | } | |
987 | ||
988 | err = ubi_read(c->ubi, lnum, buf, offs, len); | |
989 | if (err && err != -EBADMSG) | |
990 | return err; | |
991 | ||
992 | while (len >= 8) { | |
993 | int ret; | |
994 | ||
995 | cond_resched(); | |
996 | ||
997 | /* Scan quietly until there is an error */ | |
998 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet); | |
999 | ||
1000 | if (ret == SCANNED_A_NODE) { | |
1001 | /* A valid node, and not a padding node */ | |
1002 | struct ubifs_ch *ch = buf; | |
1003 | int node_len; | |
1004 | ||
1005 | node_len = ALIGN(le32_to_cpu(ch->len), 8); | |
1006 | offs += node_len; | |
1007 | buf += node_len; | |
1008 | len -= node_len; | |
1009 | continue; | |
1010 | } | |
1011 | ||
1012 | if (ret > 0) { | |
1013 | /* Padding bytes or a valid padding node */ | |
1014 | offs += ret; | |
1015 | buf += ret; | |
1016 | len -= ret; | |
1017 | continue; | |
1018 | } | |
1019 | ||
1020 | if (ret == SCANNED_EMPTY_SPACE) { | |
1021 | ubifs_err("unexpected empty space at %d:%d", | |
1022 | lnum, offs); | |
1023 | return -EUCLEAN; | |
1024 | } | |
1025 | ||
1026 | if (quiet) { | |
1027 | /* Redo the last scan but noisily */ | |
1028 | quiet = 0; | |
1029 | continue; | |
1030 | } | |
1031 | ||
1032 | ubifs_scanned_corruption(c, lnum, offs, buf); | |
1033 | return -EUCLEAN; | |
1034 | } | |
1035 | ||
1036 | /* Pad to min_io_size */ | |
1037 | len = ALIGN(ucleb->endpt, c->min_io_size); | |
1038 | if (len > ucleb->endpt) { | |
1039 | int pad_len = len - ALIGN(ucleb->endpt, 8); | |
1040 | ||
1041 | if (pad_len > 0) { | |
1042 | buf = c->sbuf + len - pad_len; | |
1043 | ubifs_pad(c, buf, pad_len); | |
1044 | } | |
1045 | } | |
1046 | ||
1047 | /* Write back the LEB atomically */ | |
1048 | err = ubi_leb_change(c->ubi, lnum, sbuf, len, UBI_UNKNOWN); | |
1049 | if (err) | |
1050 | return err; | |
1051 | ||
1052 | dbg_rcvry("cleaned LEB %d", lnum); | |
1053 | ||
1054 | return 0; | |
1055 | } | |
1056 | ||
1057 | /** | |
1058 | * ubifs_clean_lebs - clean LEBs recovered during read-only mount. | |
1059 | * @c: UBIFS file-system description object | |
1060 | * @sbuf: LEB-sized buffer to use | |
1061 | * | |
1062 | * This function cleans a LEB identified during recovery that needs to be | |
1063 | * written but was not because UBIFS was mounted read-only. This happens when | |
1064 | * remounting to read-write mode. | |
1065 | * | |
1066 | * This function returns %0 on success and a negative error code on failure. | |
1067 | */ | |
1068 | int ubifs_clean_lebs(const struct ubifs_info *c, void *sbuf) | |
1069 | { | |
1070 | dbg_rcvry("recovery"); | |
1071 | while (!list_empty(&c->unclean_leb_list)) { | |
1072 | struct ubifs_unclean_leb *ucleb; | |
1073 | int err; | |
1074 | ||
1075 | ucleb = list_entry(c->unclean_leb_list.next, | |
1076 | struct ubifs_unclean_leb, list); | |
1077 | err = clean_an_unclean_leb(c, ucleb, sbuf); | |
1078 | if (err) | |
1079 | return err; | |
1080 | list_del(&ucleb->list); | |
1081 | kfree(ucleb); | |
1082 | } | |
1083 | return 0; | |
1084 | } | |
1085 | ||
44744213 AB |
1086 | /** |
1087 | * grab_empty_leb - grab an empty LEB to use as GC LEB and run commit. | |
1088 | * @c: UBIFS file-system description object | |
1089 | * | |
1090 | * This is a helper function for 'ubifs_rcvry_gc_commit()' which grabs an empty | |
1091 | * LEB to be used as GC LEB (@c->gc_lnum), and then runs the commit. Returns | |
1092 | * zero in case of success and a negative error code in case of failure. | |
1093 | */ | |
1094 | static int grab_empty_leb(struct ubifs_info *c) | |
1095 | { | |
1096 | int lnum, err; | |
1097 | ||
1098 | /* | |
1099 | * Note, it is very important to first search for an empty LEB and then | |
1100 | * run the commit, not vice-versa. The reason is that there might be | |
1101 | * only one empty LEB at the moment, the one which has been the | |
1102 | * @c->gc_lnum just before the power cut happened. During the regular | |
1103 | * UBIFS operation (not now) @c->gc_lnum is marked as "taken", so no | |
1104 | * one but GC can grab it. But at this moment this single empty LEB is | |
1105 | * not marked as taken, so if we run commit - what happens? Right, the | |
1106 | * commit will grab it and write the index there. Remember that the | |
1107 | * index always expands as long as there is free space, and it only | |
1108 | * starts consolidating when we run out of space. | |
1109 | * | |
1110 | * IOW, if we run commit now, we might not be able to find a free LEB | |
1111 | * after this. | |
1112 | */ | |
1113 | lnum = ubifs_find_free_leb_for_idx(c); | |
1114 | if (lnum < 0) { | |
1115 | dbg_err("could not find an empty LEB"); | |
1116 | dbg_dump_lprops(c); | |
1117 | dbg_dump_budg(c, &c->bi); | |
1118 | return lnum; | |
1119 | } | |
1120 | ||
1121 | /* Reset the index flag */ | |
1122 | err = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0, | |
1123 | LPROPS_INDEX, 0); | |
1124 | if (err) | |
1125 | return err; | |
1126 | ||
1127 | c->gc_lnum = lnum; | |
1128 | dbg_rcvry("found empty LEB %d, run commit", lnum); | |
1129 | ||
1130 | return ubifs_run_commit(c); | |
1131 | } | |
1132 | ||
1e51764a AB |
1133 | /** |
1134 | * ubifs_rcvry_gc_commit - recover the GC LEB number and run the commit. | |
1135 | * @c: UBIFS file-system description object | |
1136 | * | |
1137 | * Out-of-place garbage collection requires always one empty LEB with which to | |
1138 | * start garbage collection. The LEB number is recorded in c->gc_lnum and is | |
1139 | * written to the master node on unmounting. In the case of an unclean unmount | |
1140 | * the value of gc_lnum recorded in the master node is out of date and cannot | |
1141 | * be used. Instead, recovery must allocate an empty LEB for this purpose. | |
1142 | * However, there may not be enough empty space, in which case it must be | |
1143 | * possible to GC the dirtiest LEB into the GC head LEB. | |
1144 | * | |
1145 | * This function also runs the commit which causes the TNC updates from | |
1146 | * size-recovery and orphans to be written to the flash. That is important to | |
1147 | * ensure correct replay order for subsequent mounts. | |
1148 | * | |
1149 | * This function returns %0 on success and a negative error code on failure. | |
1150 | */ | |
1151 | int ubifs_rcvry_gc_commit(struct ubifs_info *c) | |
1152 | { | |
1153 | struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf; | |
1154 | struct ubifs_lprops lp; | |
fe79c05f | 1155 | int err; |
1e51764a | 1156 | |
c839e297 AB |
1157 | dbg_rcvry("GC head LEB %d, offs %d", wbuf->lnum, wbuf->offs); |
1158 | ||
1e51764a | 1159 | c->gc_lnum = -1; |
c839e297 | 1160 | if (wbuf->lnum == -1 || wbuf->offs == c->leb_size) |
44744213 | 1161 | return grab_empty_leb(c); |
fe79c05f | 1162 | |
1e51764a AB |
1163 | err = ubifs_find_dirty_leb(c, &lp, wbuf->offs, 2); |
1164 | if (err) { | |
fe79c05f AB |
1165 | if (err != -ENOSPC) |
1166 | return err; | |
1167 | ||
1168 | dbg_rcvry("could not find a dirty LEB"); | |
1169 | return grab_empty_leb(c); | |
1e51764a | 1170 | } |
2405f594 | 1171 | |
1e51764a | 1172 | ubifs_assert(!(lp.flags & LPROPS_INDEX)); |
bcdca3e1 | 1173 | ubifs_assert(lp.free + lp.dirty >= wbuf->offs); |
2405f594 | 1174 | |
1e51764a AB |
1175 | /* |
1176 | * We run the commit before garbage collection otherwise subsequent | |
1177 | * mounts will see the GC and orphan deletion in a different order. | |
1178 | */ | |
1179 | dbg_rcvry("committing"); | |
1180 | err = ubifs_run_commit(c); | |
1181 | if (err) | |
1182 | return err; | |
fe79c05f AB |
1183 | |
1184 | dbg_rcvry("GC'ing LEB %d", lp.lnum); | |
1e51764a AB |
1185 | mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); |
1186 | err = ubifs_garbage_collect_leb(c, &lp); | |
1187 | if (err >= 0) { | |
1188 | int err2 = ubifs_wbuf_sync_nolock(wbuf); | |
1189 | ||
1190 | if (err2) | |
1191 | err = err2; | |
1192 | } | |
1193 | mutex_unlock(&wbuf->io_mutex); | |
1194 | if (err < 0) { | |
1195 | dbg_err("GC failed, error %d", err); | |
1196 | if (err == -EAGAIN) | |
1197 | err = -EINVAL; | |
1198 | return err; | |
1199 | } | |
fe79c05f AB |
1200 | |
1201 | ubifs_assert(err == LEB_RETAINED); | |
1202 | if (err != LEB_RETAINED) | |
1e51764a | 1203 | return -EINVAL; |
fe79c05f | 1204 | |
1e51764a AB |
1205 | err = ubifs_leb_unmap(c, c->gc_lnum); |
1206 | if (err) | |
1207 | return err; | |
fe79c05f AB |
1208 | |
1209 | dbg_rcvry("allocated LEB %d for GC", lp.lnum); | |
1e51764a | 1210 | return 0; |
1e51764a AB |
1211 | } |
1212 | ||
1213 | /** | |
1214 | * struct size_entry - inode size information for recovery. | |
1215 | * @rb: link in the RB-tree of sizes | |
1216 | * @inum: inode number | |
1217 | * @i_size: size on inode | |
1218 | * @d_size: maximum size based on data nodes | |
1219 | * @exists: indicates whether the inode exists | |
1220 | * @inode: inode if pinned in memory awaiting rw mode to fix it | |
1221 | */ | |
1222 | struct size_entry { | |
1223 | struct rb_node rb; | |
1224 | ino_t inum; | |
1225 | loff_t i_size; | |
1226 | loff_t d_size; | |
1227 | int exists; | |
1228 | struct inode *inode; | |
1229 | }; | |
1230 | ||
1231 | /** | |
1232 | * add_ino - add an entry to the size tree. | |
1233 | * @c: UBIFS file-system description object | |
1234 | * @inum: inode number | |
1235 | * @i_size: size on inode | |
1236 | * @d_size: maximum size based on data nodes | |
1237 | * @exists: indicates whether the inode exists | |
1238 | */ | |
1239 | static int add_ino(struct ubifs_info *c, ino_t inum, loff_t i_size, | |
1240 | loff_t d_size, int exists) | |
1241 | { | |
1242 | struct rb_node **p = &c->size_tree.rb_node, *parent = NULL; | |
1243 | struct size_entry *e; | |
1244 | ||
1245 | while (*p) { | |
1246 | parent = *p; | |
1247 | e = rb_entry(parent, struct size_entry, rb); | |
1248 | if (inum < e->inum) | |
1249 | p = &(*p)->rb_left; | |
1250 | else | |
1251 | p = &(*p)->rb_right; | |
1252 | } | |
1253 | ||
1254 | e = kzalloc(sizeof(struct size_entry), GFP_KERNEL); | |
1255 | if (!e) | |
1256 | return -ENOMEM; | |
1257 | ||
1258 | e->inum = inum; | |
1259 | e->i_size = i_size; | |
1260 | e->d_size = d_size; | |
1261 | e->exists = exists; | |
1262 | ||
1263 | rb_link_node(&e->rb, parent, p); | |
1264 | rb_insert_color(&e->rb, &c->size_tree); | |
1265 | ||
1266 | return 0; | |
1267 | } | |
1268 | ||
1269 | /** | |
1270 | * find_ino - find an entry on the size tree. | |
1271 | * @c: UBIFS file-system description object | |
1272 | * @inum: inode number | |
1273 | */ | |
1274 | static struct size_entry *find_ino(struct ubifs_info *c, ino_t inum) | |
1275 | { | |
1276 | struct rb_node *p = c->size_tree.rb_node; | |
1277 | struct size_entry *e; | |
1278 | ||
1279 | while (p) { | |
1280 | e = rb_entry(p, struct size_entry, rb); | |
1281 | if (inum < e->inum) | |
1282 | p = p->rb_left; | |
1283 | else if (inum > e->inum) | |
1284 | p = p->rb_right; | |
1285 | else | |
1286 | return e; | |
1287 | } | |
1288 | return NULL; | |
1289 | } | |
1290 | ||
1291 | /** | |
1292 | * remove_ino - remove an entry from the size tree. | |
1293 | * @c: UBIFS file-system description object | |
1294 | * @inum: inode number | |
1295 | */ | |
1296 | static void remove_ino(struct ubifs_info *c, ino_t inum) | |
1297 | { | |
1298 | struct size_entry *e = find_ino(c, inum); | |
1299 | ||
1300 | if (!e) | |
1301 | return; | |
1302 | rb_erase(&e->rb, &c->size_tree); | |
1303 | kfree(e); | |
1304 | } | |
1305 | ||
1306 | /** | |
1307 | * ubifs_destroy_size_tree - free resources related to the size tree. | |
1308 | * @c: UBIFS file-system description object | |
1309 | */ | |
1310 | void ubifs_destroy_size_tree(struct ubifs_info *c) | |
1311 | { | |
1312 | struct rb_node *this = c->size_tree.rb_node; | |
1313 | struct size_entry *e; | |
1314 | ||
1315 | while (this) { | |
1316 | if (this->rb_left) { | |
1317 | this = this->rb_left; | |
1318 | continue; | |
1319 | } else if (this->rb_right) { | |
1320 | this = this->rb_right; | |
1321 | continue; | |
1322 | } | |
1323 | e = rb_entry(this, struct size_entry, rb); | |
1324 | if (e->inode) | |
1325 | iput(e->inode); | |
1326 | this = rb_parent(this); | |
1327 | if (this) { | |
1328 | if (this->rb_left == &e->rb) | |
1329 | this->rb_left = NULL; | |
1330 | else | |
1331 | this->rb_right = NULL; | |
1332 | } | |
1333 | kfree(e); | |
1334 | } | |
1335 | c->size_tree = RB_ROOT; | |
1336 | } | |
1337 | ||
1338 | /** | |
1339 | * ubifs_recover_size_accum - accumulate inode sizes for recovery. | |
1340 | * @c: UBIFS file-system description object | |
1341 | * @key: node key | |
1342 | * @deletion: node is for a deletion | |
1343 | * @new_size: inode size | |
1344 | * | |
1345 | * This function has two purposes: | |
1346 | * 1) to ensure there are no data nodes that fall outside the inode size | |
1347 | * 2) to ensure there are no data nodes for inodes that do not exist | |
1348 | * To accomplish those purposes, a rb-tree is constructed containing an entry | |
1349 | * for each inode number in the journal that has not been deleted, and recording | |
1350 | * the size from the inode node, the maximum size of any data node (also altered | |
1351 | * by truncations) and a flag indicating a inode number for which no inode node | |
1352 | * was present in the journal. | |
1353 | * | |
1354 | * Note that there is still the possibility that there are data nodes that have | |
1355 | * been committed that are beyond the inode size, however the only way to find | |
1356 | * them would be to scan the entire index. Alternatively, some provision could | |
1357 | * be made to record the size of inodes at the start of commit, which would seem | |
1358 | * very cumbersome for a scenario that is quite unlikely and the only negative | |
1359 | * consequence of which is wasted space. | |
1360 | * | |
1361 | * This functions returns %0 on success and a negative error code on failure. | |
1362 | */ | |
1363 | int ubifs_recover_size_accum(struct ubifs_info *c, union ubifs_key *key, | |
1364 | int deletion, loff_t new_size) | |
1365 | { | |
1366 | ino_t inum = key_inum(c, key); | |
1367 | struct size_entry *e; | |
1368 | int err; | |
1369 | ||
1370 | switch (key_type(c, key)) { | |
1371 | case UBIFS_INO_KEY: | |
1372 | if (deletion) | |
1373 | remove_ino(c, inum); | |
1374 | else { | |
1375 | e = find_ino(c, inum); | |
1376 | if (e) { | |
1377 | e->i_size = new_size; | |
1378 | e->exists = 1; | |
1379 | } else { | |
1380 | err = add_ino(c, inum, new_size, 0, 1); | |
1381 | if (err) | |
1382 | return err; | |
1383 | } | |
1384 | } | |
1385 | break; | |
1386 | case UBIFS_DATA_KEY: | |
1387 | e = find_ino(c, inum); | |
1388 | if (e) { | |
1389 | if (new_size > e->d_size) | |
1390 | e->d_size = new_size; | |
1391 | } else { | |
1392 | err = add_ino(c, inum, 0, new_size, 0); | |
1393 | if (err) | |
1394 | return err; | |
1395 | } | |
1396 | break; | |
1397 | case UBIFS_TRUN_KEY: | |
1398 | e = find_ino(c, inum); | |
1399 | if (e) | |
1400 | e->d_size = new_size; | |
1401 | break; | |
1402 | } | |
1403 | return 0; | |
1404 | } | |
1405 | ||
1406 | /** | |
1407 | * fix_size_in_place - fix inode size in place on flash. | |
1408 | * @c: UBIFS file-system description object | |
1409 | * @e: inode size information for recovery | |
1410 | */ | |
1411 | static int fix_size_in_place(struct ubifs_info *c, struct size_entry *e) | |
1412 | { | |
1413 | struct ubifs_ino_node *ino = c->sbuf; | |
1414 | unsigned char *p; | |
1415 | union ubifs_key key; | |
1416 | int err, lnum, offs, len; | |
1417 | loff_t i_size; | |
1418 | uint32_t crc; | |
1419 | ||
1420 | /* Locate the inode node LEB number and offset */ | |
1421 | ino_key_init(c, &key, e->inum); | |
1422 | err = ubifs_tnc_locate(c, &key, ino, &lnum, &offs); | |
1423 | if (err) | |
1424 | goto out; | |
1425 | /* | |
1426 | * If the size recorded on the inode node is greater than the size that | |
1427 | * was calculated from nodes in the journal then don't change the inode. | |
1428 | */ | |
1429 | i_size = le64_to_cpu(ino->size); | |
1430 | if (i_size >= e->d_size) | |
1431 | return 0; | |
1432 | /* Read the LEB */ | |
1433 | err = ubi_read(c->ubi, lnum, c->sbuf, 0, c->leb_size); | |
1434 | if (err) | |
1435 | goto out; | |
1436 | /* Change the size field and recalculate the CRC */ | |
1437 | ino = c->sbuf + offs; | |
1438 | ino->size = cpu_to_le64(e->d_size); | |
1439 | len = le32_to_cpu(ino->ch.len); | |
1440 | crc = crc32(UBIFS_CRC32_INIT, (void *)ino + 8, len - 8); | |
1441 | ino->ch.crc = cpu_to_le32(crc); | |
1442 | /* Work out where data in the LEB ends and free space begins */ | |
1443 | p = c->sbuf; | |
1444 | len = c->leb_size - 1; | |
1445 | while (p[len] == 0xff) | |
1446 | len -= 1; | |
1447 | len = ALIGN(len + 1, c->min_io_size); | |
1448 | /* Atomically write the fixed LEB back again */ | |
1449 | err = ubi_leb_change(c->ubi, lnum, c->sbuf, len, UBI_UNKNOWN); | |
1450 | if (err) | |
1451 | goto out; | |
69f8a75a | 1452 | dbg_rcvry("inode %lu at %d:%d size %lld -> %lld", |
e84461ad | 1453 | (unsigned long)e->inum, lnum, offs, i_size, e->d_size); |
1e51764a AB |
1454 | return 0; |
1455 | ||
1456 | out: | |
1457 | ubifs_warn("inode %lu failed to fix size %lld -> %lld error %d", | |
e84461ad | 1458 | (unsigned long)e->inum, e->i_size, e->d_size, err); |
1e51764a AB |
1459 | return err; |
1460 | } | |
1461 | ||
1462 | /** | |
1463 | * ubifs_recover_size - recover inode size. | |
1464 | * @c: UBIFS file-system description object | |
1465 | * | |
1466 | * This function attempts to fix inode size discrepancies identified by the | |
1467 | * 'ubifs_recover_size_accum()' function. | |
1468 | * | |
1469 | * This functions returns %0 on success and a negative error code on failure. | |
1470 | */ | |
1471 | int ubifs_recover_size(struct ubifs_info *c) | |
1472 | { | |
1473 | struct rb_node *this = rb_first(&c->size_tree); | |
1474 | ||
1475 | while (this) { | |
1476 | struct size_entry *e; | |
1477 | int err; | |
1478 | ||
1479 | e = rb_entry(this, struct size_entry, rb); | |
1480 | if (!e->exists) { | |
1481 | union ubifs_key key; | |
1482 | ||
1483 | ino_key_init(c, &key, e->inum); | |
1484 | err = ubifs_tnc_lookup(c, &key, c->sbuf); | |
1485 | if (err && err != -ENOENT) | |
1486 | return err; | |
1487 | if (err == -ENOENT) { | |
1488 | /* Remove data nodes that have no inode */ | |
e84461ad AB |
1489 | dbg_rcvry("removing ino %lu", |
1490 | (unsigned long)e->inum); | |
1e51764a AB |
1491 | err = ubifs_tnc_remove_ino(c, e->inum); |
1492 | if (err) | |
1493 | return err; | |
1494 | } else { | |
1495 | struct ubifs_ino_node *ino = c->sbuf; | |
1496 | ||
1497 | e->exists = 1; | |
1498 | e->i_size = le64_to_cpu(ino->size); | |
1499 | } | |
1500 | } | |
69f8a75a | 1501 | |
1e51764a | 1502 | if (e->exists && e->i_size < e->d_size) { |
69f8a75a | 1503 | if (c->ro_mount) { |
1e51764a AB |
1504 | /* Fix the inode size and pin it in memory */ |
1505 | struct inode *inode; | |
c1f1f91d | 1506 | struct ubifs_inode *ui; |
1e51764a | 1507 | |
69f8a75a AB |
1508 | ubifs_assert(!e->inode); |
1509 | ||
1e51764a AB |
1510 | inode = ubifs_iget(c->vfs_sb, e->inum); |
1511 | if (IS_ERR(inode)) | |
1512 | return PTR_ERR(inode); | |
c1f1f91d AB |
1513 | |
1514 | ui = ubifs_inode(inode); | |
1e51764a AB |
1515 | if (inode->i_size < e->d_size) { |
1516 | dbg_rcvry("ino %lu size %lld -> %lld", | |
e84461ad | 1517 | (unsigned long)e->inum, |
4c954520 | 1518 | inode->i_size, e->d_size); |
1e51764a | 1519 | inode->i_size = e->d_size; |
c1f1f91d AB |
1520 | ui->ui_size = e->d_size; |
1521 | ui->synced_i_size = e->d_size; | |
1e51764a AB |
1522 | e->inode = inode; |
1523 | this = rb_next(this); | |
1524 | continue; | |
1525 | } | |
1526 | iput(inode); | |
1527 | } else { | |
1528 | /* Fix the size in place */ | |
1529 | err = fix_size_in_place(c, e); | |
1530 | if (err) | |
1531 | return err; | |
1532 | if (e->inode) | |
1533 | iput(e->inode); | |
1534 | } | |
1535 | } | |
69f8a75a | 1536 | |
1e51764a AB |
1537 | this = rb_next(this); |
1538 | rb_erase(&e->rb, &c->size_tree); | |
1539 | kfree(e); | |
1540 | } | |
69f8a75a | 1541 | |
1e51764a AB |
1542 | return 0; |
1543 | } |