blob: 2a935b317232b6ff87e408143c410ca3b745501f [file] [log] [blame]
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001/*
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
André Goddard Rosaaf901ca2009-11-14 13:09:05 -020026 * an un-mount was completed successfully. If not, the process of mounting
Artem Bityutskiy6fb43742010-05-23 15:20:21 +030027 * incorporates additional checking and fixing of on-flash data structures.
Artem Bityutskiy1e517642008-07-14 19:08:37 +030028 * 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.
Artem Bityutskiybe7b42a2011-02-06 16:41:06 +020031 *
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
Artem Bityutskiy2765df72011-02-02 09:22:54 +020041 * writes in @c->max_write_size bytes at a time.
Artem Bityutskiybe7b42a2011-02-06 16:41:06 +020042 *
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.
Artem Bityutskiy1e517642008-07-14 19:08:37 +030048 */
49
50#include <linux/crc32.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090051#include <linux/slab.h>
Artem Bityutskiy1e517642008-07-14 19:08:37 +030052#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 */
62static 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
73/**
Artem Bityutskiy06112542009-06-29 19:27:14 +030074 * 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 */
81static 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
92/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +030093 * 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 */
109static 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
Artem Bityutskiyd3048202011-06-03 14:03:25 +0300120 err = ubifs_leb_read(c, lnum, sbuf, 0, c->leb_size, 0);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300121 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
188out_err:
189 err = -EINVAL;
190out_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 */
204static 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;
Harvey Harrison0ecb9522008-10-24 10:52:57 -0700208 __le32 save_flags;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300209
210 dbg_rcvry("recovery");
211
212 save_flags = mst->flags;
Harvey Harrison0ecb9522008-10-24 10:52:57 -0700213 mst->flags |= cpu_to_le32(UBIFS_MST_RCVRY);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300214
215 ubifs_prepare_node(c, mst, UBIFS_MST_NODE_SZ, 1);
Artem Bityutskiyd3b25782011-06-03 14:22:05 +0300216 err = ubifs_leb_change(c, lnum, mst, sz, UBI_SHORTTERM);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300217 if (err)
218 goto out;
Artem Bityutskiyd3b25782011-06-03 14:22:05 +0300219 err = ubifs_leb_change(c, lnum + 1, mst, sz, UBI_SHORTTERM);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300220 if (err)
221 goto out;
222out:
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 */
236int 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;
Anatolij Gustschin19495f72011-07-07 12:25:02 +0200277 } else if (offs1 == 0 &&
278 c->leb_size - offs2 - sz < sz) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300279 /* 1st LEB was unmapped and written, 2nd not */
280 if (cor1)
281 goto out_err;
282 mst = mst1;
283 } else
284 goto out_err;
285 } else {
286 /*
287 * 2nd LEB was unmapped and about to be written, so
288 * there must be only one master node in the first LEB
289 * and no corruption.
290 */
291 if (offs1 != 0 || cor1)
292 goto out_err;
293 mst = mst1;
294 }
295 } else {
296 if (!mst2)
297 goto out_err;
298 /*
299 * 1st LEB was unmapped and about to be written, so there must
300 * be no room left in 2nd LEB.
301 */
302 offs2 = (void *)mst2 - buf2;
303 if (offs2 + sz + sz <= c->leb_size)
304 goto out_err;
305 mst = mst2;
306 }
307
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300308 ubifs_msg("recovered master node from LEB %d",
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300309 (mst == mst1 ? UBIFS_MST_LNUM : UBIFS_MST_LNUM + 1));
310
311 memcpy(c->mst_node, mst, UBIFS_MST_NODE_SZ);
312
Artem Bityutskiy2ef13292010-09-19 18:34:26 +0300313 if (c->ro_mount) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300314 /* Read-only mode. Keep a copy for switching to rw mode */
315 c->rcvrd_mst_node = kmalloc(sz, GFP_KERNEL);
316 if (!c->rcvrd_mst_node) {
317 err = -ENOMEM;
318 goto out_free;
319 }
320 memcpy(c->rcvrd_mst_node, c->mst_node, UBIFS_MST_NODE_SZ);
Artem Bityutskiy6e0d9fd2011-04-21 14:49:55 +0300321
322 /*
323 * We had to recover the master node, which means there was an
324 * unclean reboot. However, it is possible that the master node
325 * is clean at this point, i.e., %UBIFS_MST_DIRTY is not set.
326 * E.g., consider the following chain of events:
327 *
328 * 1. UBIFS was cleanly unmounted, so the master node is clean
329 * 2. UBIFS is being mounted R/W and starts changing the master
330 * node in the first (%UBIFS_MST_LNUM). A power cut happens,
331 * so this LEB ends up with some amount of garbage at the
332 * end.
333 * 3. UBIFS is being mounted R/O. We reach this place and
334 * recover the master node from the second LEB
335 * (%UBIFS_MST_LNUM + 1). But we cannot update the media
336 * because we are being mounted R/O. We have to defer the
337 * operation.
338 * 4. However, this master node (@c->mst_node) is marked as
339 * clean (since the step 1). And if we just return, the
340 * mount code will be confused and won't recover the master
341 * node when it is re-mounter R/W later.
342 *
343 * Thus, to force the recovery by marking the master node as
344 * dirty.
345 */
346 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300347 } else {
348 /* Write the recovered master node */
349 c->max_sqnum = le64_to_cpu(mst->ch.sqnum) - 1;
350 err = write_rcvrd_mst_node(c, c->mst_node);
351 if (err)
352 goto out_free;
353 }
354
355 vfree(buf2);
356 vfree(buf1);
357
358 return 0;
359
360out_err:
361 err = -EINVAL;
362out_free:
363 ubifs_err("failed to recover master node");
364 if (mst1) {
365 dbg_err("dumping first master node");
366 dbg_dump_node(c, mst1);
367 }
368 if (mst2) {
369 dbg_err("dumping second master node");
370 dbg_dump_node(c, mst2);
371 }
372 vfree(buf2);
373 vfree(buf1);
374 return err;
375}
376
377/**
378 * ubifs_write_rcvrd_mst_node - write the recovered master node.
379 * @c: UBIFS file-system description object
380 *
381 * This function writes the master node that was recovered during mounting in
382 * read-only mode and must now be written because we are remounting rw.
383 *
384 * This function returns %0 on success and a negative error code on failure.
385 */
386int ubifs_write_rcvrd_mst_node(struct ubifs_info *c)
387{
388 int err;
389
390 if (!c->rcvrd_mst_node)
391 return 0;
392 c->rcvrd_mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
393 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
394 err = write_rcvrd_mst_node(c, c->rcvrd_mst_node);
395 if (err)
396 return err;
397 kfree(c->rcvrd_mst_node);
398 c->rcvrd_mst_node = NULL;
399 return 0;
400}
401
402/**
403 * is_last_write - determine if an offset was in the last write to a LEB.
404 * @c: UBIFS file-system description object
405 * @buf: buffer to check
406 * @offs: offset to check
407 *
408 * This function returns %1 if @offs was in the last write to the LEB whose data
Artem Bityutskiy2765df72011-02-02 09:22:54 +0200409 * is in @buf, otherwise %0 is returned. The determination is made by checking
410 * for subsequent empty space starting from the next @c->max_write_size
411 * boundary.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300412 */
413static int is_last_write(const struct ubifs_info *c, void *buf, int offs)
414{
Artem Bityutskiy428ff9d2009-05-25 16:59:28 +0300415 int empty_offs, check_len;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300416 uint8_t *p;
417
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300418 /*
Artem Bityutskiy2765df72011-02-02 09:22:54 +0200419 * Round up to the next @c->max_write_size boundary i.e. @offs is in
420 * the last wbuf written. After that should be empty space.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300421 */
Artem Bityutskiy2765df72011-02-02 09:22:54 +0200422 empty_offs = ALIGN(offs + 1, c->max_write_size);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300423 check_len = c->leb_size - empty_offs;
424 p = buf + empty_offs - offs;
Artem Bityutskiy431102f2009-06-29 18:58:34 +0300425 return is_empty(p, check_len);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300426}
427
428/**
429 * clean_buf - clean the data from an LEB sitting in a buffer.
430 * @c: UBIFS file-system description object
431 * @buf: buffer to clean
432 * @lnum: LEB number to clean
433 * @offs: offset from which to clean
434 * @len: length of buffer
435 *
436 * This function pads up to the next min_io_size boundary (if there is one) and
437 * sets empty space to all 0xff. @buf, @offs and @len are updated to the next
Artem Bityutskiy428ff9d2009-05-25 16:59:28 +0300438 * @c->min_io_size boundary.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300439 */
440static void clean_buf(const struct ubifs_info *c, void **buf, int lnum,
441 int *offs, int *len)
442{
443 int empty_offs, pad_len;
444
445 lnum = lnum;
446 dbg_rcvry("cleaning corruption at %d:%d", lnum, *offs);
447
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300448 ubifs_assert(!(*offs & 7));
449 empty_offs = ALIGN(*offs, c->min_io_size);
450 pad_len = empty_offs - *offs;
451 ubifs_pad(c, *buf, pad_len);
452 *offs += pad_len;
453 *buf += pad_len;
454 *len -= pad_len;
455 memset(*buf, 0xff, c->leb_size - empty_offs);
456}
457
458/**
459 * no_more_nodes - determine if there are no more nodes in a buffer.
460 * @c: UBIFS file-system description object
461 * @buf: buffer to check
462 * @len: length of buffer
463 * @lnum: LEB number of the LEB from which @buf was read
464 * @offs: offset from which @buf was read
465 *
Adrian Hunterde097572009-03-20 11:09:04 +0100466 * This function ensures that the corrupted node at @offs is the last thing
467 * written to a LEB. This function returns %1 if more data is not found and
468 * %0 if more data is found.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300469 */
470static int no_more_nodes(const struct ubifs_info *c, void *buf, int len,
471 int lnum, int offs)
472{
Adrian Hunterde097572009-03-20 11:09:04 +0100473 struct ubifs_ch *ch = buf;
474 int skip, dlen = le32_to_cpu(ch->len);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300475
Adrian Hunterde097572009-03-20 11:09:04 +0100476 /* Check for empty space after the corrupt node's common header */
Artem Bityutskiy2765df72011-02-02 09:22:54 +0200477 skip = ALIGN(offs + UBIFS_CH_SZ, c->max_write_size) - offs;
Adrian Hunterde097572009-03-20 11:09:04 +0100478 if (is_empty(buf + skip, len - skip))
479 return 1;
480 /*
481 * The area after the common header size is not empty, so the common
482 * header must be intact. Check it.
483 */
484 if (ubifs_check_node(c, buf, lnum, offs, 1, 0) != -EUCLEAN) {
485 dbg_rcvry("unexpected bad common header at %d:%d", lnum, offs);
486 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300487 }
Adrian Hunterde097572009-03-20 11:09:04 +0100488 /* Now we know the corrupt node's length we can skip over it */
Artem Bityutskiy2765df72011-02-02 09:22:54 +0200489 skip = ALIGN(offs + dlen, c->max_write_size) - offs;
Adrian Hunterde097572009-03-20 11:09:04 +0100490 /* After which there should be empty space */
491 if (is_empty(buf + skip, len - skip))
492 return 1;
493 dbg_rcvry("unexpected data at %d:%d", lnum, offs + skip);
494 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300495}
496
497/**
498 * fix_unclean_leb - fix an unclean LEB.
499 * @c: UBIFS file-system description object
500 * @sleb: scanned LEB information
501 * @start: offset where scan started
502 */
503static int fix_unclean_leb(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
504 int start)
505{
506 int lnum = sleb->lnum, endpt = start;
507
508 /* Get the end offset of the last node we are keeping */
509 if (!list_empty(&sleb->nodes)) {
510 struct ubifs_scan_node *snod;
511
512 snod = list_entry(sleb->nodes.prev,
513 struct ubifs_scan_node, list);
514 endpt = snod->offs + snod->len;
515 }
516
Artem Bityutskiy2ef13292010-09-19 18:34:26 +0300517 if (c->ro_mount && !c->remounting_rw) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300518 /* Add to recovery list */
519 struct ubifs_unclean_leb *ucleb;
520
521 dbg_rcvry("need to fix LEB %d start %d endpt %d",
522 lnum, start, sleb->endpt);
523 ucleb = kzalloc(sizeof(struct ubifs_unclean_leb), GFP_NOFS);
524 if (!ucleb)
525 return -ENOMEM;
526 ucleb->lnum = lnum;
527 ucleb->endpt = endpt;
528 list_add_tail(&ucleb->list, &c->unclean_leb_list);
529 } else {
530 /* Write the fixed LEB back to flash */
531 int err;
532
533 dbg_rcvry("fixing LEB %d start %d endpt %d",
534 lnum, start, sleb->endpt);
535 if (endpt == 0) {
536 err = ubifs_leb_unmap(c, lnum);
537 if (err)
538 return err;
539 } else {
540 int len = ALIGN(endpt, c->min_io_size);
541
542 if (start) {
Artem Bityutskiyd3048202011-06-03 14:03:25 +0300543 err = ubifs_leb_read(c, lnum, sleb->buf, 0,
544 start, 1);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300545 if (err)
546 return err;
547 }
548 /* Pad to min_io_size */
549 if (len > endpt) {
550 int pad_len = len - ALIGN(endpt, 8);
551
552 if (pad_len > 0) {
553 void *buf = sleb->buf + len - pad_len;
554
555 ubifs_pad(c, buf, pad_len);
556 }
557 }
Artem Bityutskiyd3b25782011-06-03 14:22:05 +0300558 err = ubifs_leb_change(c, lnum, sleb->buf, len,
559 UBI_UNKNOWN);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300560 if (err)
561 return err;
562 }
563 }
564 return 0;
565}
566
567/**
Artem Bityutskiyda8b94e2011-05-26 08:58:19 +0300568 * drop_last_group - drop the last group of nodes.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300569 * @sleb: scanned LEB information
570 * @offs: offset of dropped nodes is returned here
571 *
Artem Bityutskiybbf2b372011-05-16 15:15:52 +0300572 * This is a helper function for 'ubifs_recover_leb()' which drops the last
Artem Bityutskiyda8b94e2011-05-26 08:58:19 +0300573 * group of nodes of the scanned LEB.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300574 */
Artem Bityutskiyda8b94e2011-05-26 08:58:19 +0300575static void drop_last_group(struct ubifs_scan_leb *sleb, int *offs)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300576{
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300577 while (!list_empty(&sleb->nodes)) {
578 struct ubifs_scan_node *snod;
579 struct ubifs_ch *ch;
580
581 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
582 list);
583 ch = snod->node;
584 if (ch->group_type != UBIFS_IN_NODE_GROUP)
Artem Bityutskiyda8b94e2011-05-26 08:58:19 +0300585 break;
586
587 dbg_rcvry("dropping grouped node at %d:%d",
588 sleb->lnum, snod->offs);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300589 *offs = snod->offs;
590 list_del(&snod->list);
591 kfree(snod);
592 sleb->nodes_cnt -= 1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300593 }
Artem Bityutskiyda8b94e2011-05-26 08:58:19 +0300594}
595
596/**
597 * drop_last_node - drop the last node.
598 * @sleb: scanned LEB information
599 * @offs: offset of dropped nodes is returned here
600 * @grouped: non-zero if whole group of nodes have to be dropped
601 *
602 * This is a helper function for 'ubifs_recover_leb()' which drops the last
603 * node of the scanned LEB.
604 */
605static void drop_last_node(struct ubifs_scan_leb *sleb, int *offs)
606{
607 struct ubifs_scan_node *snod;
608
609 if (!list_empty(&sleb->nodes)) {
610 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
611 list);
612
613 dbg_rcvry("dropping last node at %d:%d", sleb->lnum, snod->offs);
614 *offs = snod->offs;
615 list_del(&snod->list);
616 kfree(snod);
617 sleb->nodes_cnt -= 1;
618 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300619}
620
621/**
622 * ubifs_recover_leb - scan and recover a LEB.
623 * @c: UBIFS file-system description object
624 * @lnum: LEB number
625 * @offs: offset
626 * @sbuf: LEB-sized buffer to use
Artem Bityutskiyefcfde52011-05-26 08:36:52 +0300627 * @jhead: journal head number this LEB belongs to (%-1 if the LEB does not
628 * belong to any journal head)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300629 *
630 * This function does a scan of a LEB, but caters for errors that might have
631 * been caused by the unclean unmount from which we are attempting to recover.
Artem Bityutskiyed43f2f2009-06-29 17:59:23 +0300632 * Returns %0 in case of success, %-EUCLEAN if an unrecoverable corruption is
633 * found, and a negative error code in case of failure.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300634 */
635struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum,
Artem Bityutskiyefcfde52011-05-26 08:36:52 +0300636 int offs, void *sbuf, int jhead)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300637{
Artem Bityutskiybbf2b372011-05-16 15:15:52 +0300638 int ret = 0, err, len = c->leb_size - offs, start = offs, min_io_unit;
Artem Bityutskiyefcfde52011-05-26 08:36:52 +0300639 int grouped = jhead == -1 ? 0 : c->jheads[jhead].grouped;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300640 struct ubifs_scan_leb *sleb;
641 void *buf = sbuf + offs;
642
Artem Bityutskiyefcfde52011-05-26 08:36:52 +0300643 dbg_rcvry("%d:%d, jhead %d, grouped %d", lnum, offs, jhead, grouped);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300644
645 sleb = ubifs_start_scan(c, lnum, offs, sbuf);
646 if (IS_ERR(sleb))
647 return sleb;
648
Artem Bityutskiybbf2b372011-05-16 15:15:52 +0300649 ubifs_assert(len >= 8);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300650 while (len >= 8) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300651 dbg_scan("look at LEB %d:%d (%d bytes left)",
652 lnum, offs, len);
653
654 cond_resched();
655
656 /*
657 * Scan quietly until there is an error from which we cannot
658 * recover
659 */
Artem Bityutskiyab759502011-05-26 06:51:48 +0300660 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300661 if (ret == SCANNED_A_NODE) {
662 /* A valid node, and not a padding node */
663 struct ubifs_ch *ch = buf;
664 int node_len;
665
666 err = ubifs_add_snod(c, sleb, buf, offs);
667 if (err)
668 goto error;
669 node_len = ALIGN(le32_to_cpu(ch->len), 8);
670 offs += node_len;
671 buf += node_len;
672 len -= node_len;
Artem Bityutskiy61799202011-05-16 13:41:55 +0300673 } else if (ret > 0) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300674 /* Padding bytes or a valid padding node */
675 offs += ret;
676 buf += ret;
677 len -= ret;
Artem Bityutskiy61799202011-05-16 13:41:55 +0300678 } else if (ret == SCANNED_EMPTY_SPACE ||
679 ret == SCANNED_GARBAGE ||
680 ret == SCANNED_A_BAD_PAD_NODE ||
681 ret == SCANNED_A_CORRUPT_NODE) {
Artem Bityutskiy78437362012-01-16 12:10:56 +0200682 dbg_rcvry("found corruption (%d) at %d:%d",
683 ret, lnum, offs);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300684 break;
Artem Bityutskiy61799202011-05-16 13:41:55 +0300685 } else {
686 dbg_err("unexpected return value %d", ret);
Artem Bityutskiyed43f2f2009-06-29 17:59:23 +0300687 err = -EINVAL;
688 goto error;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300689 }
690 }
691
Artem Bityutskiy61799202011-05-16 13:41:55 +0300692 if (ret == SCANNED_GARBAGE || ret == SCANNED_A_BAD_PAD_NODE) {
Artem Bityutskiy43e07072011-05-16 14:21:51 +0300693 if (!is_last_write(c, buf, offs))
Artem Bityutskiy61799202011-05-16 13:41:55 +0300694 goto corrupted_rescan;
695 } else if (ret == SCANNED_A_CORRUPT_NODE) {
Artem Bityutskiy43e07072011-05-16 14:21:51 +0300696 if (!no_more_nodes(c, buf, len, lnum, offs))
Artem Bityutskiy61799202011-05-16 13:41:55 +0300697 goto corrupted_rescan;
698 } else if (!is_empty(buf, len)) {
Artem Bityutskiy43e07072011-05-16 14:21:51 +0300699 if (!is_last_write(c, buf, offs)) {
Artem Bityutskiy06112542009-06-29 19:27:14 +0300700 int corruption = first_non_ff(buf, len);
701
Artem Bityutskiybe7b42a2011-02-06 16:41:06 +0200702 /*
703 * See header comment for this file for more
704 * explanations about the reasons we have this check.
705 */
Artem Bityutskiy06112542009-06-29 19:27:14 +0300706 ubifs_err("corrupt empty space LEB %d:%d, corruption "
707 "starts at %d", lnum, offs, corruption);
708 /* Make sure we dump interesting non-0xFF data */
Artem Bityutskiy10ac2792011-02-08 17:21:11 +0200709 offs += corruption;
Artem Bityutskiy06112542009-06-29 19:27:14 +0300710 buf += corruption;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300711 goto corrupted;
712 }
713 }
714
Artem Bityutskiybbf2b372011-05-16 15:15:52 +0300715 min_io_unit = round_down(offs, c->min_io_size);
716 if (grouped)
717 /*
718 * If nodes are grouped, always drop the incomplete group at
719 * the end.
720 */
Artem Bityutskiyda8b94e2011-05-26 08:58:19 +0300721 drop_last_group(sleb, &offs);
Artem Bityutskiybbf2b372011-05-16 15:15:52 +0300722
Artem Bityutskiyda8b94e2011-05-26 08:58:19 +0300723 if (jhead == GCHD) {
724 /*
725 * If this LEB belongs to the GC head then while we are in the
726 * middle of the same min. I/O unit keep dropping nodes. So
727 * basically, what we want is to make sure that the last min.
728 * I/O unit where we saw the corruption is dropped completely
729 * with all the uncorrupted nodes which may possibly sit there.
730 *
731 * In other words, let's name the min. I/O unit where the
732 * corruption starts B, and the previous min. I/O unit A. The
733 * below code tries to deal with a situation when half of B
734 * contains valid nodes or the end of a valid node, and the
735 * second half of B contains corrupted data or garbage. This
736 * means that UBIFS had been writing to B just before the power
737 * cut happened. I do not know how realistic is this scenario
738 * that half of the min. I/O unit had been written successfully
739 * and the other half not, but this is possible in our 'failure
740 * mode emulation' infrastructure at least.
741 *
742 * So what is the problem, why we need to drop those nodes? Why
743 * can't we just clean-up the second half of B by putting a
744 * padding node there? We can, and this works fine with one
745 * exception which was reproduced with power cut emulation
746 * testing and happens extremely rarely.
747 *
748 * Imagine the file-system is full, we run GC which starts
749 * moving valid nodes from LEB X to LEB Y (obviously, LEB Y is
750 * the current GC head LEB). The @c->gc_lnum is -1, which means
751 * that GC will retain LEB X and will try to continue. Imagine
752 * that LEB X is currently the dirtiest LEB, and the amount of
753 * used space in LEB Y is exactly the same as amount of free
754 * space in LEB X.
755 *
756 * And a power cut happens when nodes are moved from LEB X to
757 * LEB Y. We are here trying to recover LEB Y which is the GC
758 * head LEB. We find the min. I/O unit B as described above.
759 * Then we clean-up LEB Y by padding min. I/O unit. And later
760 * 'ubifs_rcvry_gc_commit()' function fails, because it cannot
761 * find a dirty LEB which could be GC'd into LEB Y! Even LEB X
762 * does not match because the amount of valid nodes there does
763 * not fit the free space in LEB Y any more! And this is
764 * because of the padding node which we added to LEB Y. The
765 * user-visible effect of this which I once observed and
766 * analysed is that we cannot mount the file-system with
767 * -ENOSPC error.
768 *
769 * So obviously, to make sure that situation does not happen we
770 * should free min. I/O unit B in LEB Y completely and the last
771 * used min. I/O unit in LEB Y should be A. This is basically
772 * what the below code tries to do.
773 */
774 while (offs > min_io_unit)
775 drop_last_node(sleb, &offs);
776 }
Artem Bityutskiybbf2b372011-05-16 15:15:52 +0300777
778 buf = sbuf + offs;
779 len = c->leb_size - offs;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300780
Artem Bityutskiy43e07072011-05-16 14:21:51 +0300781 clean_buf(c, &buf, lnum, &offs, &len);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300782 ubifs_end_scan(c, sleb, lnum, offs);
783
Artem Bityutskiy7c47bfd2011-05-16 13:44:48 +0300784 err = fix_unclean_leb(c, sleb, start);
785 if (err)
786 goto error;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300787
788 return sleb;
789
Artem Bityutskiy61799202011-05-16 13:41:55 +0300790corrupted_rescan:
791 /* Re-scan the corrupted data with verbose messages */
792 dbg_err("corruptio %d", ret);
793 ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300794corrupted:
795 ubifs_scanned_corruption(c, lnum, offs, buf);
796 err = -EUCLEAN;
797error:
798 ubifs_err("LEB %d scanning failed", lnum);
799 ubifs_scan_destroy(sleb);
800 return ERR_PTR(err);
801}
802
803/**
804 * get_cs_sqnum - get commit start sequence number.
805 * @c: UBIFS file-system description object
806 * @lnum: LEB number of commit start node
807 * @offs: offset of commit start node
808 * @cs_sqnum: commit start sequence number is returned here
809 *
810 * This function returns %0 on success and a negative error code on failure.
811 */
812static int get_cs_sqnum(struct ubifs_info *c, int lnum, int offs,
813 unsigned long long *cs_sqnum)
814{
815 struct ubifs_cs_node *cs_node = NULL;
816 int err, ret;
817
818 dbg_rcvry("at %d:%d", lnum, offs);
819 cs_node = kmalloc(UBIFS_CS_NODE_SZ, GFP_KERNEL);
820 if (!cs_node)
821 return -ENOMEM;
822 if (c->leb_size - offs < UBIFS_CS_NODE_SZ)
823 goto out_err;
Artem Bityutskiyd3048202011-06-03 14:03:25 +0300824 err = ubifs_leb_read(c, lnum, (void *)cs_node, offs,
825 UBIFS_CS_NODE_SZ, 0);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300826 if (err && err != -EBADMSG)
827 goto out_free;
828 ret = ubifs_scan_a_node(c, cs_node, UBIFS_CS_NODE_SZ, lnum, offs, 0);
829 if (ret != SCANNED_A_NODE) {
830 dbg_err("Not a valid node");
831 goto out_err;
832 }
833 if (cs_node->ch.node_type != UBIFS_CS_NODE) {
834 dbg_err("Node a CS node, type is %d", cs_node->ch.node_type);
835 goto out_err;
836 }
837 if (le64_to_cpu(cs_node->cmt_no) != c->cmt_no) {
838 dbg_err("CS node cmt_no %llu != current cmt_no %llu",
839 (unsigned long long)le64_to_cpu(cs_node->cmt_no),
840 c->cmt_no);
841 goto out_err;
842 }
843 *cs_sqnum = le64_to_cpu(cs_node->ch.sqnum);
844 dbg_rcvry("commit start sqnum %llu", *cs_sqnum);
845 kfree(cs_node);
846 return 0;
847
848out_err:
849 err = -EINVAL;
850out_free:
851 ubifs_err("failed to get CS sqnum");
852 kfree(cs_node);
853 return err;
854}
855
856/**
857 * ubifs_recover_log_leb - scan and recover a log LEB.
858 * @c: UBIFS file-system description object
859 * @lnum: LEB number
860 * @offs: offset
861 * @sbuf: LEB-sized buffer to use
862 *
863 * This function does a scan of a LEB, but caters for errors that might have
Artem Bityutskiy7d08ae32010-10-17 15:50:19 +0300864 * been caused by unclean reboots from which we are attempting to recover
865 * (assume that only the last log LEB can be corrupted by an unclean reboot).
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300866 *
867 * This function returns %0 on success and a negative error code on failure.
868 */
869struct ubifs_scan_leb *ubifs_recover_log_leb(struct ubifs_info *c, int lnum,
870 int offs, void *sbuf)
871{
872 struct ubifs_scan_leb *sleb;
873 int next_lnum;
874
875 dbg_rcvry("LEB %d", lnum);
876 next_lnum = lnum + 1;
877 if (next_lnum >= UBIFS_LOG_LNUM + c->log_lebs)
878 next_lnum = UBIFS_LOG_LNUM;
879 if (next_lnum != c->ltail_lnum) {
880 /*
881 * We can only recover at the end of the log, so check that the
882 * next log LEB is empty or out of date.
883 */
Artem Bityutskiy348709b2009-08-25 15:00:55 +0300884 sleb = ubifs_scan(c, next_lnum, 0, sbuf, 0);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300885 if (IS_ERR(sleb))
886 return sleb;
887 if (sleb->nodes_cnt) {
888 struct ubifs_scan_node *snod;
889 unsigned long long cs_sqnum = c->cs_sqnum;
890
891 snod = list_entry(sleb->nodes.next,
892 struct ubifs_scan_node, list);
893 if (cs_sqnum == 0) {
894 int err;
895
896 err = get_cs_sqnum(c, lnum, offs, &cs_sqnum);
897 if (err) {
898 ubifs_scan_destroy(sleb);
899 return ERR_PTR(err);
900 }
901 }
902 if (snod->sqnum > cs_sqnum) {
903 ubifs_err("unrecoverable log corruption "
904 "in LEB %d", lnum);
905 ubifs_scan_destroy(sleb);
906 return ERR_PTR(-EUCLEAN);
907 }
908 }
909 ubifs_scan_destroy(sleb);
910 }
Artem Bityutskiyefcfde52011-05-26 08:36:52 +0300911 return ubifs_recover_leb(c, lnum, offs, sbuf, -1);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300912}
913
914/**
915 * recover_head - recover a head.
916 * @c: UBIFS file-system description object
917 * @lnum: LEB number of head to recover
918 * @offs: offset of head to recover
919 * @sbuf: LEB-sized buffer to use
920 *
921 * This function ensures that there is no data on the flash at a head location.
922 *
923 * This function returns %0 on success and a negative error code on failure.
924 */
Artem Bityutskiy83cef702011-06-03 13:45:09 +0300925static int recover_head(struct ubifs_info *c, int lnum, int offs, void *sbuf)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300926{
Artem Bityutskiy2765df72011-02-02 09:22:54 +0200927 int len = c->max_write_size, err;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300928
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300929 if (offs + len > c->leb_size)
930 len = c->leb_size - offs;
931
932 if (!len)
933 return 0;
934
935 /* Read at the head location and check it is empty flash */
Artem Bityutskiyd3048202011-06-03 14:03:25 +0300936 err = ubifs_leb_read(c, lnum, sbuf, offs, len, 1);
Artem Bityutskiy431102f2009-06-29 18:58:34 +0300937 if (err || !is_empty(sbuf, len)) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300938 dbg_rcvry("cleaning head at %d:%d", lnum, offs);
939 if (offs == 0)
940 return ubifs_leb_unmap(c, lnum);
Artem Bityutskiyd3048202011-06-03 14:03:25 +0300941 err = ubifs_leb_read(c, lnum, sbuf, 0, offs, 1);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300942 if (err)
943 return err;
Artem Bityutskiyd3b25782011-06-03 14:22:05 +0300944 return ubifs_leb_change(c, lnum, sbuf, offs, UBI_UNKNOWN);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300945 }
946
947 return 0;
948}
949
950/**
951 * ubifs_recover_inl_heads - recover index and LPT heads.
952 * @c: UBIFS file-system description object
953 * @sbuf: LEB-sized buffer to use
954 *
955 * This function ensures that there is no data on the flash at the index and
956 * LPT head locations.
957 *
958 * This deals with the recovery of a half-completed journal commit. UBIFS is
959 * careful never to overwrite the last version of the index or the LPT. Because
960 * the index and LPT are wandering trees, data from a half-completed commit will
961 * not be referenced anywhere in UBIFS. The data will be either in LEBs that are
962 * assumed to be empty and will be unmapped anyway before use, or in the index
963 * and LPT heads.
964 *
965 * This function returns %0 on success and a negative error code on failure.
966 */
Artem Bityutskiy83cef702011-06-03 13:45:09 +0300967int ubifs_recover_inl_heads(struct ubifs_info *c, void *sbuf)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300968{
969 int err;
970
Artem Bityutskiy2ef13292010-09-19 18:34:26 +0300971 ubifs_assert(!c->ro_mount || c->remounting_rw);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300972
973 dbg_rcvry("checking index head at %d:%d", c->ihead_lnum, c->ihead_offs);
974 err = recover_head(c, c->ihead_lnum, c->ihead_offs, sbuf);
975 if (err)
976 return err;
977
978 dbg_rcvry("checking LPT head at %d:%d", c->nhead_lnum, c->nhead_offs);
979 err = recover_head(c, c->nhead_lnum, c->nhead_offs, sbuf);
980 if (err)
981 return err;
982
983 return 0;
984}
985
986/**
srimugunthan dhandapani7606f852011-08-26 16:08:39 +0530987 * clean_an_unclean_leb - read and write a LEB to remove corruption.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300988 * @c: UBIFS file-system description object
989 * @ucleb: unclean LEB information
990 * @sbuf: LEB-sized buffer to use
991 *
992 * This function reads a LEB up to a point pre-determined by the mount recovery,
993 * checks the nodes, and writes the result back to the flash, thereby cleaning
994 * off any following corruption, or non-fatal ECC errors.
995 *
996 * This function returns %0 on success and a negative error code on failure.
997 */
Artem Bityutskiy83cef702011-06-03 13:45:09 +0300998static int clean_an_unclean_leb(struct ubifs_info *c,
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300999 struct ubifs_unclean_leb *ucleb, void *sbuf)
1000{
1001 int err, lnum = ucleb->lnum, offs = 0, len = ucleb->endpt, quiet = 1;
1002 void *buf = sbuf;
1003
1004 dbg_rcvry("LEB %d len %d", lnum, len);
1005
1006 if (len == 0) {
1007 /* Nothing to read, just unmap it */
1008 err = ubifs_leb_unmap(c, lnum);
1009 if (err)
1010 return err;
1011 return 0;
1012 }
1013
Artem Bityutskiyd3048202011-06-03 14:03:25 +03001014 err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001015 if (err && err != -EBADMSG)
1016 return err;
1017
1018 while (len >= 8) {
1019 int ret;
1020
1021 cond_resched();
1022
1023 /* Scan quietly until there is an error */
1024 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
1025
1026 if (ret == SCANNED_A_NODE) {
1027 /* A valid node, and not a padding node */
1028 struct ubifs_ch *ch = buf;
1029 int node_len;
1030
1031 node_len = ALIGN(le32_to_cpu(ch->len), 8);
1032 offs += node_len;
1033 buf += node_len;
1034 len -= node_len;
1035 continue;
1036 }
1037
1038 if (ret > 0) {
1039 /* Padding bytes or a valid padding node */
1040 offs += ret;
1041 buf += ret;
1042 len -= ret;
1043 continue;
1044 }
1045
1046 if (ret == SCANNED_EMPTY_SPACE) {
1047 ubifs_err("unexpected empty space at %d:%d",
1048 lnum, offs);
1049 return -EUCLEAN;
1050 }
1051
1052 if (quiet) {
1053 /* Redo the last scan but noisily */
1054 quiet = 0;
1055 continue;
1056 }
1057
1058 ubifs_scanned_corruption(c, lnum, offs, buf);
1059 return -EUCLEAN;
1060 }
1061
1062 /* Pad to min_io_size */
1063 len = ALIGN(ucleb->endpt, c->min_io_size);
1064 if (len > ucleb->endpt) {
1065 int pad_len = len - ALIGN(ucleb->endpt, 8);
1066
1067 if (pad_len > 0) {
1068 buf = c->sbuf + len - pad_len;
1069 ubifs_pad(c, buf, pad_len);
1070 }
1071 }
1072
1073 /* Write back the LEB atomically */
Artem Bityutskiyd3b25782011-06-03 14:22:05 +03001074 err = ubifs_leb_change(c, lnum, sbuf, len, UBI_UNKNOWN);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001075 if (err)
1076 return err;
1077
1078 dbg_rcvry("cleaned LEB %d", lnum);
1079
1080 return 0;
1081}
1082
1083/**
1084 * ubifs_clean_lebs - clean LEBs recovered during read-only mount.
1085 * @c: UBIFS file-system description object
1086 * @sbuf: LEB-sized buffer to use
1087 *
1088 * This function cleans a LEB identified during recovery that needs to be
1089 * written but was not because UBIFS was mounted read-only. This happens when
1090 * remounting to read-write mode.
1091 *
1092 * This function returns %0 on success and a negative error code on failure.
1093 */
Artem Bityutskiy83cef702011-06-03 13:45:09 +03001094int ubifs_clean_lebs(struct ubifs_info *c, void *sbuf)
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001095{
1096 dbg_rcvry("recovery");
1097 while (!list_empty(&c->unclean_leb_list)) {
1098 struct ubifs_unclean_leb *ucleb;
1099 int err;
1100
1101 ucleb = list_entry(c->unclean_leb_list.next,
1102 struct ubifs_unclean_leb, list);
1103 err = clean_an_unclean_leb(c, ucleb, sbuf);
1104 if (err)
1105 return err;
1106 list_del(&ucleb->list);
1107 kfree(ucleb);
1108 }
1109 return 0;
1110}
1111
1112/**
Artem Bityutskiy44744212011-04-27 14:52:35 +03001113 * grab_empty_leb - grab an empty LEB to use as GC LEB and run commit.
1114 * @c: UBIFS file-system description object
1115 *
1116 * This is a helper function for 'ubifs_rcvry_gc_commit()' which grabs an empty
1117 * LEB to be used as GC LEB (@c->gc_lnum), and then runs the commit. Returns
1118 * zero in case of success and a negative error code in case of failure.
1119 */
1120static int grab_empty_leb(struct ubifs_info *c)
1121{
1122 int lnum, err;
1123
1124 /*
1125 * Note, it is very important to first search for an empty LEB and then
1126 * run the commit, not vice-versa. The reason is that there might be
1127 * only one empty LEB at the moment, the one which has been the
1128 * @c->gc_lnum just before the power cut happened. During the regular
1129 * UBIFS operation (not now) @c->gc_lnum is marked as "taken", so no
1130 * one but GC can grab it. But at this moment this single empty LEB is
1131 * not marked as taken, so if we run commit - what happens? Right, the
1132 * commit will grab it and write the index there. Remember that the
1133 * index always expands as long as there is free space, and it only
1134 * starts consolidating when we run out of space.
1135 *
1136 * IOW, if we run commit now, we might not be able to find a free LEB
1137 * after this.
1138 */
1139 lnum = ubifs_find_free_leb_for_idx(c);
1140 if (lnum < 0) {
1141 dbg_err("could not find an empty LEB");
1142 dbg_dump_lprops(c);
1143 dbg_dump_budg(c, &c->bi);
1144 return lnum;
1145 }
1146
1147 /* Reset the index flag */
1148 err = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
1149 LPROPS_INDEX, 0);
1150 if (err)
1151 return err;
1152
1153 c->gc_lnum = lnum;
1154 dbg_rcvry("found empty LEB %d, run commit", lnum);
1155
1156 return ubifs_run_commit(c);
1157}
1158
1159/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001160 * ubifs_rcvry_gc_commit - recover the GC LEB number and run the commit.
1161 * @c: UBIFS file-system description object
1162 *
1163 * Out-of-place garbage collection requires always one empty LEB with which to
1164 * start garbage collection. The LEB number is recorded in c->gc_lnum and is
1165 * written to the master node on unmounting. In the case of an unclean unmount
1166 * the value of gc_lnum recorded in the master node is out of date and cannot
1167 * be used. Instead, recovery must allocate an empty LEB for this purpose.
1168 * However, there may not be enough empty space, in which case it must be
1169 * possible to GC the dirtiest LEB into the GC head LEB.
1170 *
1171 * This function also runs the commit which causes the TNC updates from
1172 * size-recovery and orphans to be written to the flash. That is important to
1173 * ensure correct replay order for subsequent mounts.
1174 *
1175 * This function returns %0 on success and a negative error code on failure.
1176 */
1177int ubifs_rcvry_gc_commit(struct ubifs_info *c)
1178{
1179 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
1180 struct ubifs_lprops lp;
Artem Bityutskiyfe79c052011-04-29 16:35:46 +03001181 int err;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001182
Artem Bityutskiyc839e292011-05-13 12:26:54 +03001183 dbg_rcvry("GC head LEB %d, offs %d", wbuf->lnum, wbuf->offs);
1184
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001185 c->gc_lnum = -1;
Artem Bityutskiyc839e292011-05-13 12:26:54 +03001186 if (wbuf->lnum == -1 || wbuf->offs == c->leb_size)
Artem Bityutskiy44744212011-04-27 14:52:35 +03001187 return grab_empty_leb(c);
Artem Bityutskiyfe79c052011-04-29 16:35:46 +03001188
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001189 err = ubifs_find_dirty_leb(c, &lp, wbuf->offs, 2);
1190 if (err) {
Artem Bityutskiyfe79c052011-04-29 16:35:46 +03001191 if (err != -ENOSPC)
1192 return err;
1193
1194 dbg_rcvry("could not find a dirty LEB");
1195 return grab_empty_leb(c);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001196 }
Artem Bityutskiy2405f592011-04-26 09:49:32 +03001197
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001198 ubifs_assert(!(lp.flags & LPROPS_INDEX));
Artem Bityutskiybcdca3e2011-04-26 10:07:50 +03001199 ubifs_assert(lp.free + lp.dirty >= wbuf->offs);
Artem Bityutskiy2405f592011-04-26 09:49:32 +03001200
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001201 /*
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001202 * We run the commit before garbage collection otherwise subsequent
1203 * mounts will see the GC and orphan deletion in a different order.
1204 */
1205 dbg_rcvry("committing");
1206 err = ubifs_run_commit(c);
1207 if (err)
1208 return err;
Artem Bityutskiyfe79c052011-04-29 16:35:46 +03001209
1210 dbg_rcvry("GC'ing LEB %d", lp.lnum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001211 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
1212 err = ubifs_garbage_collect_leb(c, &lp);
1213 if (err >= 0) {
1214 int err2 = ubifs_wbuf_sync_nolock(wbuf);
1215
1216 if (err2)
1217 err = err2;
1218 }
1219 mutex_unlock(&wbuf->io_mutex);
1220 if (err < 0) {
1221 dbg_err("GC failed, error %d", err);
1222 if (err == -EAGAIN)
1223 err = -EINVAL;
1224 return err;
1225 }
Artem Bityutskiyfe79c052011-04-29 16:35:46 +03001226
1227 ubifs_assert(err == LEB_RETAINED);
1228 if (err != LEB_RETAINED)
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001229 return -EINVAL;
Artem Bityutskiyfe79c052011-04-29 16:35:46 +03001230
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001231 err = ubifs_leb_unmap(c, c->gc_lnum);
1232 if (err)
1233 return err;
Artem Bityutskiyfe79c052011-04-29 16:35:46 +03001234
1235 dbg_rcvry("allocated LEB %d for GC", lp.lnum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001236 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001237}
1238
1239/**
1240 * struct size_entry - inode size information for recovery.
1241 * @rb: link in the RB-tree of sizes
1242 * @inum: inode number
1243 * @i_size: size on inode
1244 * @d_size: maximum size based on data nodes
1245 * @exists: indicates whether the inode exists
1246 * @inode: inode if pinned in memory awaiting rw mode to fix it
1247 */
1248struct size_entry {
1249 struct rb_node rb;
1250 ino_t inum;
1251 loff_t i_size;
1252 loff_t d_size;
1253 int exists;
1254 struct inode *inode;
1255};
1256
1257/**
1258 * add_ino - add an entry to the size tree.
1259 * @c: UBIFS file-system description object
1260 * @inum: inode number
1261 * @i_size: size on inode
1262 * @d_size: maximum size based on data nodes
1263 * @exists: indicates whether the inode exists
1264 */
1265static int add_ino(struct ubifs_info *c, ino_t inum, loff_t i_size,
1266 loff_t d_size, int exists)
1267{
1268 struct rb_node **p = &c->size_tree.rb_node, *parent = NULL;
1269 struct size_entry *e;
1270
1271 while (*p) {
1272 parent = *p;
1273 e = rb_entry(parent, struct size_entry, rb);
1274 if (inum < e->inum)
1275 p = &(*p)->rb_left;
1276 else
1277 p = &(*p)->rb_right;
1278 }
1279
1280 e = kzalloc(sizeof(struct size_entry), GFP_KERNEL);
1281 if (!e)
1282 return -ENOMEM;
1283
1284 e->inum = inum;
1285 e->i_size = i_size;
1286 e->d_size = d_size;
1287 e->exists = exists;
1288
1289 rb_link_node(&e->rb, parent, p);
1290 rb_insert_color(&e->rb, &c->size_tree);
1291
1292 return 0;
1293}
1294
1295/**
1296 * find_ino - find an entry on the size tree.
1297 * @c: UBIFS file-system description object
1298 * @inum: inode number
1299 */
1300static struct size_entry *find_ino(struct ubifs_info *c, ino_t inum)
1301{
1302 struct rb_node *p = c->size_tree.rb_node;
1303 struct size_entry *e;
1304
1305 while (p) {
1306 e = rb_entry(p, struct size_entry, rb);
1307 if (inum < e->inum)
1308 p = p->rb_left;
1309 else if (inum > e->inum)
1310 p = p->rb_right;
1311 else
1312 return e;
1313 }
1314 return NULL;
1315}
1316
1317/**
1318 * remove_ino - remove an entry from the size tree.
1319 * @c: UBIFS file-system description object
1320 * @inum: inode number
1321 */
1322static void remove_ino(struct ubifs_info *c, ino_t inum)
1323{
1324 struct size_entry *e = find_ino(c, inum);
1325
1326 if (!e)
1327 return;
1328 rb_erase(&e->rb, &c->size_tree);
1329 kfree(e);
1330}
1331
1332/**
1333 * ubifs_destroy_size_tree - free resources related to the size tree.
1334 * @c: UBIFS file-system description object
1335 */
1336void ubifs_destroy_size_tree(struct ubifs_info *c)
1337{
1338 struct rb_node *this = c->size_tree.rb_node;
1339 struct size_entry *e;
1340
1341 while (this) {
1342 if (this->rb_left) {
1343 this = this->rb_left;
1344 continue;
1345 } else if (this->rb_right) {
1346 this = this->rb_right;
1347 continue;
1348 }
1349 e = rb_entry(this, struct size_entry, rb);
1350 if (e->inode)
1351 iput(e->inode);
1352 this = rb_parent(this);
1353 if (this) {
1354 if (this->rb_left == &e->rb)
1355 this->rb_left = NULL;
1356 else
1357 this->rb_right = NULL;
1358 }
1359 kfree(e);
1360 }
1361 c->size_tree = RB_ROOT;
1362}
1363
1364/**
1365 * ubifs_recover_size_accum - accumulate inode sizes for recovery.
1366 * @c: UBIFS file-system description object
1367 * @key: node key
1368 * @deletion: node is for a deletion
1369 * @new_size: inode size
1370 *
1371 * This function has two purposes:
1372 * 1) to ensure there are no data nodes that fall outside the inode size
1373 * 2) to ensure there are no data nodes for inodes that do not exist
1374 * To accomplish those purposes, a rb-tree is constructed containing an entry
1375 * for each inode number in the journal that has not been deleted, and recording
1376 * the size from the inode node, the maximum size of any data node (also altered
1377 * by truncations) and a flag indicating a inode number for which no inode node
1378 * was present in the journal.
1379 *
1380 * Note that there is still the possibility that there are data nodes that have
1381 * been committed that are beyond the inode size, however the only way to find
1382 * them would be to scan the entire index. Alternatively, some provision could
1383 * be made to record the size of inodes at the start of commit, which would seem
1384 * very cumbersome for a scenario that is quite unlikely and the only negative
1385 * consequence of which is wasted space.
1386 *
1387 * This functions returns %0 on success and a negative error code on failure.
1388 */
1389int ubifs_recover_size_accum(struct ubifs_info *c, union ubifs_key *key,
1390 int deletion, loff_t new_size)
1391{
1392 ino_t inum = key_inum(c, key);
1393 struct size_entry *e;
1394 int err;
1395
1396 switch (key_type(c, key)) {
1397 case UBIFS_INO_KEY:
1398 if (deletion)
1399 remove_ino(c, inum);
1400 else {
1401 e = find_ino(c, inum);
1402 if (e) {
1403 e->i_size = new_size;
1404 e->exists = 1;
1405 } else {
1406 err = add_ino(c, inum, new_size, 0, 1);
1407 if (err)
1408 return err;
1409 }
1410 }
1411 break;
1412 case UBIFS_DATA_KEY:
1413 e = find_ino(c, inum);
1414 if (e) {
1415 if (new_size > e->d_size)
1416 e->d_size = new_size;
1417 } else {
1418 err = add_ino(c, inum, 0, new_size, 0);
1419 if (err)
1420 return err;
1421 }
1422 break;
1423 case UBIFS_TRUN_KEY:
1424 e = find_ino(c, inum);
1425 if (e)
1426 e->d_size = new_size;
1427 break;
1428 }
1429 return 0;
1430}
1431
1432/**
1433 * fix_size_in_place - fix inode size in place on flash.
1434 * @c: UBIFS file-system description object
1435 * @e: inode size information for recovery
1436 */
1437static int fix_size_in_place(struct ubifs_info *c, struct size_entry *e)
1438{
1439 struct ubifs_ino_node *ino = c->sbuf;
1440 unsigned char *p;
1441 union ubifs_key key;
1442 int err, lnum, offs, len;
1443 loff_t i_size;
1444 uint32_t crc;
1445
1446 /* Locate the inode node LEB number and offset */
1447 ino_key_init(c, &key, e->inum);
1448 err = ubifs_tnc_locate(c, &key, ino, &lnum, &offs);
1449 if (err)
1450 goto out;
1451 /*
1452 * If the size recorded on the inode node is greater than the size that
1453 * was calculated from nodes in the journal then don't change the inode.
1454 */
1455 i_size = le64_to_cpu(ino->size);
1456 if (i_size >= e->d_size)
1457 return 0;
1458 /* Read the LEB */
Artem Bityutskiyd3048202011-06-03 14:03:25 +03001459 err = ubifs_leb_read(c, lnum, c->sbuf, 0, c->leb_size, 1);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001460 if (err)
1461 goto out;
1462 /* Change the size field and recalculate the CRC */
1463 ino = c->sbuf + offs;
1464 ino->size = cpu_to_le64(e->d_size);
1465 len = le32_to_cpu(ino->ch.len);
1466 crc = crc32(UBIFS_CRC32_INIT, (void *)ino + 8, len - 8);
1467 ino->ch.crc = cpu_to_le32(crc);
1468 /* Work out where data in the LEB ends and free space begins */
1469 p = c->sbuf;
1470 len = c->leb_size - 1;
1471 while (p[len] == 0xff)
1472 len -= 1;
1473 len = ALIGN(len + 1, c->min_io_size);
1474 /* Atomically write the fixed LEB back again */
Artem Bityutskiyd3b25782011-06-03 14:22:05 +03001475 err = ubifs_leb_change(c, lnum, c->sbuf, len, UBI_UNKNOWN);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001476 if (err)
1477 goto out;
Artem Bityutskiy69f8a752011-05-02 21:51:17 +03001478 dbg_rcvry("inode %lu at %d:%d size %lld -> %lld",
Artem Bityutskiye84461a2008-10-29 12:08:43 +02001479 (unsigned long)e->inum, lnum, offs, i_size, e->d_size);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001480 return 0;
1481
1482out:
1483 ubifs_warn("inode %lu failed to fix size %lld -> %lld error %d",
Artem Bityutskiye84461a2008-10-29 12:08:43 +02001484 (unsigned long)e->inum, e->i_size, e->d_size, err);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001485 return err;
1486}
1487
1488/**
1489 * ubifs_recover_size - recover inode size.
1490 * @c: UBIFS file-system description object
1491 *
1492 * This function attempts to fix inode size discrepancies identified by the
1493 * 'ubifs_recover_size_accum()' function.
1494 *
1495 * This functions returns %0 on success and a negative error code on failure.
1496 */
1497int ubifs_recover_size(struct ubifs_info *c)
1498{
1499 struct rb_node *this = rb_first(&c->size_tree);
1500
1501 while (this) {
1502 struct size_entry *e;
1503 int err;
1504
1505 e = rb_entry(this, struct size_entry, rb);
1506 if (!e->exists) {
1507 union ubifs_key key;
1508
1509 ino_key_init(c, &key, e->inum);
1510 err = ubifs_tnc_lookup(c, &key, c->sbuf);
1511 if (err && err != -ENOENT)
1512 return err;
1513 if (err == -ENOENT) {
1514 /* Remove data nodes that have no inode */
Artem Bityutskiye84461a2008-10-29 12:08:43 +02001515 dbg_rcvry("removing ino %lu",
1516 (unsigned long)e->inum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001517 err = ubifs_tnc_remove_ino(c, e->inum);
1518 if (err)
1519 return err;
1520 } else {
1521 struct ubifs_ino_node *ino = c->sbuf;
1522
1523 e->exists = 1;
1524 e->i_size = le64_to_cpu(ino->size);
1525 }
1526 }
Artem Bityutskiy69f8a752011-05-02 21:51:17 +03001527
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001528 if (e->exists && e->i_size < e->d_size) {
Artem Bityutskiy69f8a752011-05-02 21:51:17 +03001529 if (c->ro_mount) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001530 /* Fix the inode size and pin it in memory */
1531 struct inode *inode;
Artem Bityutskiyc1f1f912011-05-05 14:16:32 +03001532 struct ubifs_inode *ui;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001533
Artem Bityutskiy69f8a752011-05-02 21:51:17 +03001534 ubifs_assert(!e->inode);
1535
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001536 inode = ubifs_iget(c->vfs_sb, e->inum);
1537 if (IS_ERR(inode))
1538 return PTR_ERR(inode);
Artem Bityutskiyc1f1f912011-05-05 14:16:32 +03001539
1540 ui = ubifs_inode(inode);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001541 if (inode->i_size < e->d_size) {
1542 dbg_rcvry("ino %lu size %lld -> %lld",
Artem Bityutskiye84461a2008-10-29 12:08:43 +02001543 (unsigned long)e->inum,
Artem Bityutskiy4c954522011-05-02 21:43:54 +03001544 inode->i_size, e->d_size);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001545 inode->i_size = e->d_size;
Artem Bityutskiyc1f1f912011-05-05 14:16:32 +03001546 ui->ui_size = e->d_size;
1547 ui->synced_i_size = e->d_size;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001548 e->inode = inode;
1549 this = rb_next(this);
1550 continue;
1551 }
1552 iput(inode);
1553 } else {
1554 /* Fix the size in place */
1555 err = fix_size_in_place(c, e);
1556 if (err)
1557 return err;
1558 if (e->inode)
1559 iput(e->inode);
1560 }
1561 }
Artem Bityutskiy69f8a752011-05-02 21:51:17 +03001562
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001563 this = rb_next(this);
1564 rb_erase(&e->rb, &c->size_tree);
1565 kfree(e);
1566 }
Artem Bityutskiy69f8a752011-05-02 21:51:17 +03001567
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001568 return 0;
1569}