1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * This file is part of UBIFS. |
4 | * |
5 | * Copyright (C) 2006-2008 Nokia Corporation |
6 | * |
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 |
14 | * an un-mount was completed successfully. If not, the process of mounting |
15 | * incorporates additional checking and fixing of on-flash data structures. |
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. |
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 |
29 | * writes in @c->max_write_size bytes at a time. |
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. |
36 | */ |
37 | |
38 | #include <linux/crc32.h> |
39 | #include <linux/slab.h> |
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 | |
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 | |
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(size: c->leb_size); |
105 | if (!sbuf) |
106 | return -ENOMEM; |
107 | |
108 | err = ubifs_leb_read(c, lnum, buf: sbuf, offs: 0, len: c->leb_size, even_ebadmsg: 0); |
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, quiet: 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, quiet: 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(addr: 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; |
196 | __le32 save_flags; |
197 | |
198 | dbg_rcvry("recovery" ); |
199 | |
200 | save_flags = mst->flags; |
201 | mst->flags |= cpu_to_le32(UBIFS_MST_RCVRY); |
202 | |
203 | err = ubifs_prepare_node_hmac(c, node: mst, UBIFS_MST_NODE_SZ, |
204 | offsetof(struct ubifs_mst_node, hmac), pad: 1); |
205 | if (err) |
206 | goto out; |
207 | err = ubifs_leb_change(c, lnum, buf: mst, len: sz); |
208 | if (err) |
209 | goto out; |
210 | err = ubifs_leb_change(c, lnum: lnum + 1, buf: mst, len: sz); |
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, pbuf: &buf1, mst: &mst1, cor: &cor1); |
237 | if (err) |
238 | goto out_free; |
239 | |
240 | err = get_master_node(c, UBIFS_MST_LNUM + 1, pbuf: &buf2, mst: &mst2, cor: &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 */ |
258 | if (ubifs_compare_master_node(c, m1: mst1, m2: mst2)) |
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; |
266 | } else if (offs1 == 0 && |
267 | c->leb_size - offs2 - sz < sz) { |
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 | |
297 | ubifs_msg(c, fmt: "recovered master node from LEB %d" , |
298 | (mst == mst1 ? UBIFS_MST_LNUM : UBIFS_MST_LNUM + 1)); |
299 | |
300 | memcpy(c->mst_node, mst, UBIFS_MST_NODE_SZ); |
301 | |
302 | if (c->ro_mount) { |
303 | /* Read-only mode. Keep a copy for switching to rw mode */ |
304 | c->rcvrd_mst_node = kmalloc(size: 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); |
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); |
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, mst: c->mst_node); |
340 | if (err) |
341 | goto out_free; |
342 | } |
343 | |
344 | vfree(addr: buf2); |
345 | vfree(addr: buf1); |
346 | |
347 | return 0; |
348 | |
349 | out_err: |
350 | err = -EINVAL; |
351 | out_free: |
352 | ubifs_err(c, fmt: "failed to recover master node" ); |
353 | if (mst1) { |
354 | ubifs_err(c, fmt: "dumping first master node" ); |
355 | ubifs_dump_node(c, node: mst1, node_len: c->leb_size - ((void *)mst1 - buf1)); |
356 | } |
357 | if (mst2) { |
358 | ubifs_err(c, fmt: "dumping second master node" ); |
359 | ubifs_dump_node(c, node: mst2, node_len: c->leb_size - ((void *)mst2 - buf2)); |
360 | } |
361 | vfree(addr: buf2); |
362 | vfree(addr: 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, mst: c->rcvrd_mst_node); |
384 | if (err) |
385 | return err; |
386 | kfree(objp: 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 |
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. |
401 | */ |
402 | static int is_last_write(const struct ubifs_info *c, void *buf, int offs) |
403 | { |
404 | int empty_offs, check_len; |
405 | uint8_t *p; |
406 | |
407 | /* |
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. |
410 | */ |
411 | empty_offs = ALIGN(offs + 1, c->max_write_size); |
412 | check_len = c->leb_size - empty_offs; |
413 | p = buf + empty_offs - offs; |
414 | return is_empty(buf: p, len: check_len); |
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 |
427 | * @c->min_io_size boundary. |
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 | |
434 | dbg_rcvry("cleaning corruption at %d:%d" , lnum, *offs); |
435 | |
436 | ubifs_assert(c, !(*offs & 7)); |
437 | empty_offs = ALIGN(*offs, c->min_io_size); |
438 | pad_len = empty_offs - *offs; |
439 | ubifs_pad(c, buf: *buf, pad: 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 | * |
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. |
457 | */ |
458 | static int no_more_nodes(const struct ubifs_info *c, void *buf, int len, |
459 | int lnum, int offs) |
460 | { |
461 | struct ubifs_ch *ch = buf; |
462 | int skip, dlen = le32_to_cpu(ch->len); |
463 | |
464 | /* Check for empty space after the corrupt node's common header */ |
465 | skip = ALIGN(offs + UBIFS_CH_SZ, c->max_write_size) - offs; |
466 | if (is_empty(buf: buf + skip, len: 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, len, lnum, offs, quiet: 1, must_chk_crc: 0) != -EUCLEAN) { |
473 | dbg_rcvry("unexpected bad common header at %d:%d" , lnum, offs); |
474 | return 0; |
475 | } |
476 | /* Now we know the corrupt node's length we can skip over it */ |
477 | skip = ALIGN(offs + dlen, c->max_write_size) - offs; |
478 | /* After which there should be empty space */ |
479 | if (is_empty(buf: buf + skip, len: len - skip)) |
480 | return 1; |
481 | dbg_rcvry("unexpected data at %d:%d" , lnum, offs + skip); |
482 | return 0; |
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(head: &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 | |
505 | if (c->ro_mount && !c->remounting_rw) { |
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(size: 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(new: &ucleb->list, head: &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) { |
531 | err = ubifs_leb_read(c, lnum, buf: sleb->buf, offs: 0, |
532 | len: start, even_ebadmsg: 1); |
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: pad_len); |
544 | } |
545 | } |
546 | err = ubifs_leb_change(c, lnum, buf: sleb->buf, len); |
547 | if (err) |
548 | return err; |
549 | } |
550 | } |
551 | return 0; |
552 | } |
553 | |
554 | /** |
555 | * drop_last_group - drop the last group of nodes. |
556 | * @sleb: scanned LEB information |
557 | * @offs: offset of dropped nodes is returned here |
558 | * |
559 | * This is a helper function for 'ubifs_recover_leb()' which drops the last |
560 | * group of nodes of the scanned LEB. |
561 | */ |
562 | static void drop_last_group(struct ubifs_scan_leb *sleb, int *offs) |
563 | { |
564 | while (!list_empty(head: &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) |
572 | break; |
573 | |
574 | dbg_rcvry("dropping grouped node at %d:%d" , |
575 | sleb->lnum, snod->offs); |
576 | *offs = snod->offs; |
577 | list_del(entry: &snod->list); |
578 | kfree(objp: 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 |
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(head: &sleb->nodes)) { |
596 | snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, |
597 | list); |
598 | |
599 | dbg_rcvry("dropping last node at %d:%d" , |
600 | sleb->lnum, snod->offs); |
601 | *offs = snod->offs; |
602 | list_del(entry: &snod->list); |
603 | kfree(objp: snod); |
604 | sleb->nodes_cnt -= 1; |
605 | } |
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 |
614 | * @jhead: journal head number this LEB belongs to (%-1 if the LEB does not |
615 | * belong to any journal head) |
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. |
619 | * Returns the scanned information on success and a negative error code on |
620 | * failure. |
621 | */ |
622 | struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum, |
623 | int offs, void *sbuf, int jhead) |
624 | { |
625 | int ret = 0, err, len = c->leb_size - offs, start = offs, min_io_unit; |
626 | int grouped = jhead == -1 ? 0 : c->jheads[jhead].grouped; |
627 | struct ubifs_scan_leb *sleb; |
628 | void *buf = sbuf + offs; |
629 | |
630 | dbg_rcvry("%d:%d, jhead %d, grouped %d" , lnum, offs, jhead, grouped); |
631 | |
632 | sleb = ubifs_start_scan(c, lnum, offs, sbuf); |
633 | if (IS_ERR(ptr: sleb)) |
634 | return sleb; |
635 | |
636 | ubifs_assert(c, len >= 8); |
637 | while (len >= 8) { |
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 | */ |
647 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet: 1); |
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; |
660 | } else if (ret > 0) { |
661 | /* Padding bytes or a valid padding node */ |
662 | offs += ret; |
663 | buf += ret; |
664 | len -= ret; |
665 | } else if (ret == SCANNED_EMPTY_SPACE || |
666 | ret == SCANNED_GARBAGE || |
667 | ret == SCANNED_A_BAD_PAD_NODE || |
668 | ret == SCANNED_A_CORRUPT_NODE) { |
669 | dbg_rcvry("found corruption (%d) at %d:%d" , |
670 | ret, lnum, offs); |
671 | break; |
672 | } else { |
673 | ubifs_err(c, fmt: "unexpected return value %d" , ret); |
674 | err = -EINVAL; |
675 | goto error; |
676 | } |
677 | } |
678 | |
679 | if (ret == SCANNED_GARBAGE || ret == SCANNED_A_BAD_PAD_NODE) { |
680 | if (!is_last_write(c, buf, offs)) |
681 | goto corrupted_rescan; |
682 | } else if (ret == SCANNED_A_CORRUPT_NODE) { |
683 | if (!no_more_nodes(c, buf, len, lnum, offs)) |
684 | goto corrupted_rescan; |
685 | } else if (!is_empty(buf, len)) { |
686 | if (!is_last_write(c, buf, offs)) { |
687 | int corruption = first_non_ff(buf, len); |
688 | |
689 | /* |
690 | * See header comment for this file for more |
691 | * explanations about the reasons we have this check. |
692 | */ |
693 | ubifs_err(c, fmt: "corrupt empty space LEB %d:%d, corruption starts at %d" , |
694 | lnum, offs, corruption); |
695 | /* Make sure we dump interesting non-0xFF data */ |
696 | offs += corruption; |
697 | buf += corruption; |
698 | goto corrupted; |
699 | } |
700 | } |
701 | |
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 | */ |
708 | drop_last_group(sleb, offs: &offs); |
709 | |
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: &offs); |
763 | } |
764 | |
765 | buf = sbuf + offs; |
766 | len = c->leb_size - offs; |
767 | |
768 | clean_buf(c, buf: &buf, lnum, offs: &offs, len: &len); |
769 | ubifs_end_scan(c, sleb, lnum, offs); |
770 | |
771 | err = fix_unclean_leb(c, sleb, start); |
772 | if (err) |
773 | goto error; |
774 | |
775 | return sleb; |
776 | |
777 | corrupted_rescan: |
778 | /* Re-scan the corrupted data with verbose messages */ |
779 | ubifs_err(c, fmt: "corruption %d" , ret); |
780 | ubifs_scan_a_node(c, buf, len, lnum, offs, quiet: 0); |
781 | corrupted: |
782 | ubifs_scanned_corruption(c, lnum, offs, buf); |
783 | err = -EUCLEAN; |
784 | error: |
785 | ubifs_err(c, fmt: "LEB %d scanning failed" , lnum); |
786 | ubifs_scan_destroy(sleb); |
787 | return ERR_PTR(error: 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; |
811 | err = ubifs_leb_read(c, lnum, buf: (void *)cs_node, offs, |
812 | UBIFS_CS_NODE_SZ, even_ebadmsg: 0); |
813 | if (err && err != -EBADMSG) |
814 | goto out_free; |
815 | ret = ubifs_scan_a_node(c, buf: cs_node, UBIFS_CS_NODE_SZ, lnum, offs, quiet: 0); |
816 | if (ret != SCANNED_A_NODE) { |
817 | ubifs_err(c, fmt: "Not a valid node" ); |
818 | goto out_err; |
819 | } |
820 | if (cs_node->ch.node_type != UBIFS_CS_NODE) { |
821 | ubifs_err(c, fmt: "Not a CS node, type is %d" , cs_node->ch.node_type); |
822 | goto out_err; |
823 | } |
824 | if (le64_to_cpu(cs_node->cmt_no) != c->cmt_no) { |
825 | ubifs_err(c, fmt: "CS node cmt_no %llu != current cmt_no %llu" , |
826 | (unsigned long long)le64_to_cpu(cs_node->cmt_no), |
827 | c->cmt_no); |
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(objp: cs_node); |
833 | return 0; |
834 | |
835 | out_err: |
836 | err = -EINVAL; |
837 | out_free: |
838 | ubifs_err(c, fmt: "failed to get CS sqnum" ); |
839 | kfree(objp: 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 |
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). |
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 | */ |
871 | sleb = ubifs_scan(c, lnum: next_lnum, offs: 0, sbuf, quiet: 0); |
872 | if (IS_ERR(ptr: 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: &cs_sqnum); |
884 | if (err) { |
885 | ubifs_scan_destroy(sleb); |
886 | return ERR_PTR(error: err); |
887 | } |
888 | } |
889 | if (snod->sqnum > cs_sqnum) { |
890 | ubifs_err(c, fmt: "unrecoverable log corruption in LEB %d" , |
891 | lnum); |
892 | ubifs_scan_destroy(sleb); |
893 | return ERR_PTR(error: -EUCLEAN); |
894 | } |
895 | } |
896 | ubifs_scan_destroy(sleb); |
897 | } |
898 | return ubifs_recover_leb(c, lnum, offs, sbuf, jhead: -1); |
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 | */ |
912 | static int recover_head(struct ubifs_info *c, int lnum, int offs, void *sbuf) |
913 | { |
914 | int len = c->max_write_size, err; |
915 | |
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 */ |
923 | err = ubifs_leb_read(c, lnum, buf: sbuf, offs, len, even_ebadmsg: 1); |
924 | if (err || !is_empty(buf: sbuf, len)) { |
925 | dbg_rcvry("cleaning head at %d:%d" , lnum, offs); |
926 | if (offs == 0) |
927 | return ubifs_leb_unmap(c, lnum); |
928 | err = ubifs_leb_read(c, lnum, buf: sbuf, offs: 0, len: offs, even_ebadmsg: 1); |
929 | if (err) |
930 | return err; |
931 | return ubifs_leb_change(c, lnum, buf: sbuf, len: offs); |
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 | */ |
954 | int ubifs_recover_inl_heads(struct ubifs_info *c, void *sbuf) |
955 | { |
956 | int err; |
957 | |
958 | ubifs_assert(c, !c->ro_mount || c->remounting_rw); |
959 | |
960 | dbg_rcvry("checking index head at %d:%d" , c->ihead_lnum, c->ihead_offs); |
961 | err = recover_head(c, lnum: c->ihead_lnum, offs: 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); |
966 | |
967 | return recover_head(c, lnum: c->nhead_lnum, offs: c->nhead_offs, sbuf); |
968 | } |
969 | |
970 | /** |
971 | * clean_an_unclean_leb - read and write a LEB to remove corruption. |
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 | */ |
982 | static int clean_an_unclean_leb(struct ubifs_info *c, |
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 */ |
992 | return ubifs_leb_unmap(c, lnum); |
993 | } |
994 | |
995 | err = ubifs_leb_read(c, lnum, buf, offs, len, even_ebadmsg: 0); |
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) { |
1028 | ubifs_err(c, fmt: "unexpected empty space at %d:%d" , |
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: pad_len); |
1051 | } |
1052 | } |
1053 | |
1054 | /* Write back the LEB atomically */ |
1055 | err = ubifs_leb_change(c, lnum, buf: sbuf, len); |
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 | */ |
1075 | int ubifs_clean_lebs(struct ubifs_info *c, void *sbuf) |
1076 | { |
1077 | dbg_rcvry("recovery" ); |
1078 | while (!list_empty(head: &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(entry: &ucleb->list); |
1088 | kfree(objp: ucleb); |
1089 | } |
1090 | return 0; |
1091 | } |
1092 | |
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) { |
1122 | ubifs_err(c, fmt: "could not find an empty LEB" ); |
1123 | ubifs_dump_lprops(c); |
1124 | ubifs_dump_budg(c, bi: &c->bi); |
1125 | return lnum; |
1126 | } |
1127 | |
1128 | /* Reset the index flag */ |
1129 | err = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, flags_set: 0, |
1130 | flags_clean: LPROPS_INDEX, idx_gc_cnt: 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 | |
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; |
1162 | int err; |
1163 | |
1164 | dbg_rcvry("GC head LEB %d, offs %d" , wbuf->lnum, wbuf->offs); |
1165 | |
1166 | c->gc_lnum = -1; |
1167 | if (wbuf->lnum == -1 || wbuf->offs == c->leb_size) |
1168 | return grab_empty_leb(c); |
1169 | |
1170 | err = ubifs_find_dirty_leb(c, ret_lp: &lp, min_space: wbuf->offs, pick_free: 2); |
1171 | if (err) { |
1172 | if (err != -ENOSPC) |
1173 | return err; |
1174 | |
1175 | dbg_rcvry("could not find a dirty LEB" ); |
1176 | return grab_empty_leb(c); |
1177 | } |
1178 | |
1179 | ubifs_assert(c, !(lp.flags & LPROPS_INDEX)); |
1180 | ubifs_assert(c, lp.free + lp.dirty >= wbuf->offs); |
1181 | |
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; |
1190 | |
1191 | dbg_rcvry("GC'ing LEB %d" , lp.lnum); |
1192 | mutex_lock_nested(lock: &wbuf->io_mutex, subclass: wbuf->jhead); |
1193 | err = ubifs_garbage_collect_leb(c, lp: &lp); |
1194 | if (err >= 0) { |
1195 | int err2 = ubifs_wbuf_sync_nolock(wbuf); |
1196 | |
1197 | if (err2) |
1198 | err = err2; |
1199 | } |
1200 | mutex_unlock(lock: &wbuf->io_mutex); |
1201 | if (err < 0) { |
1202 | ubifs_err(c, fmt: "GC failed, error %d" , err); |
1203 | if (err == -EAGAIN) |
1204 | err = -EINVAL; |
1205 | return err; |
1206 | } |
1207 | |
1208 | ubifs_assert(c, err == LEB_RETAINED); |
1209 | if (err != LEB_RETAINED) |
1210 | return -EINVAL; |
1211 | |
1212 | err = ubifs_leb_unmap(c, lnum: c->gc_lnum); |
1213 | if (err) |
1214 | return err; |
1215 | |
1216 | dbg_rcvry("allocated LEB %d for GC" , lp.lnum); |
1217 | return 0; |
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(size: 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(node: &e->rb, parent, rb_link: 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(objp: 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 | { |
1319 | struct size_entry *e, *n; |
1320 | |
1321 | rbtree_postorder_for_each_entry_safe(e, n, &c->size_tree, rb) { |
1322 | iput(e->inode); |
1323 | kfree(objp: e); |
1324 | } |
1325 | |
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, k: 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, i_size: new_size, d_size: 0, exists: 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, i_size: 0, d_size: new_size, exists: 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: &key, inum: e->inum); |
1413 | err = ubifs_tnc_locate(c, key: &key, node: ino, lnum: &lnum, offs: &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 */ |
1424 | err = ubifs_leb_read(c, lnum, buf: c->sbuf, offs: 0, len: c->leb_size, even_ebadmsg: 1); |
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 */ |
1440 | err = ubifs_leb_change(c, lnum, buf: c->sbuf, len); |
1441 | if (err) |
1442 | goto out; |
1443 | dbg_rcvry("inode %lu at %d:%d size %lld -> %lld" , |
1444 | (unsigned long)e->inum, lnum, offs, i_size, e->d_size); |
1445 | return 0; |
1446 | |
1447 | out: |
1448 | ubifs_warn(c, fmt: "inode %lu failed to fix size %lld -> %lld error %d" , |
1449 | (unsigned long)e->inum, e->i_size, e->d_size, err); |
1450 | return err; |
1451 | } |
1452 | |
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(sb: c->vfs_sb, inum: e->inum); |
1472 | if (IS_ERR(ptr: inode)) |
1473 | return PTR_ERR(ptr: 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(objp: e); |
1514 | |
1515 | return 0; |
1516 | } |
1517 | |
1518 | /** |
1519 | * ubifs_recover_size - recover inode size. |
1520 | * @c: UBIFS file-system description object |
1521 | * @in_place: If true, do a in-place size fixup |
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 | */ |
1528 | int ubifs_recover_size(struct ubifs_info *c, bool in_place) |
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); |
1537 | |
1538 | this = rb_next(this); |
1539 | |
1540 | if (!e->exists) { |
1541 | union ubifs_key key; |
1542 | |
1543 | ino_key_init(c, key: &key, inum: e->inum); |
1544 | err = ubifs_tnc_lookup(c, key: &key, node: c->sbuf); |
1545 | if (err && err != -ENOENT) |
1546 | return err; |
1547 | if (err == -ENOENT) { |
1548 | /* Remove data nodes that have no inode */ |
1549 | dbg_rcvry("removing ino %lu" , |
1550 | (unsigned long)e->inum); |
1551 | err = ubifs_tnc_remove_ino(c, inum: 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 | } |
1561 | |
1562 | if (e->exists && e->i_size < e->d_size) { |
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) { |
1571 | err = fix_size_in_place(c, e); |
1572 | if (err) |
1573 | return err; |
1574 | iput(e->inode); |
1575 | } else { |
1576 | err = inode_fix_size(c, e); |
1577 | if (err) |
1578 | return err; |
1579 | continue; |
1580 | } |
1581 | } |
1582 | |
1583 | rb_erase(&e->rb, &c->size_tree); |
1584 | kfree(objp: e); |
1585 | } |
1586 | |
1587 | return 0; |
1588 | } |
1589 | |