| 1 | |
| 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(c->leb_size);
|
| 105 | if (!sbuf)
|
| 106 | return -ENOMEM;
|
| 107 |
|
| 108 | err = ubifs_leb_read(c, lnum, sbuf, 0, c->leb_size, 0);
|
| 109 | if (err && err != -EBADMSG)
|
| 110 | goto out_free;
|
| 111 |
|
| 112 |
|
| 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 |
|
| 126 | if (offs) {
|
| 127 | int ret;
|
| 128 |
|
| 129 | offs -= sz;
|
| 130 | buf -= sz;
|
| 131 | len += sz;
|
| 132 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
|
| 133 | if (ret != SCANNED_A_NODE && offs) {
|
| 134 |
|
| 135 | offs -= sz;
|
| 136 | buf -= sz;
|
| 137 | len += sz;
|
| 138 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
|
| 139 | if (ret != SCANNED_A_NODE)
|
| 140 | |
| 141 | * We accept only one area of corruption because
|
| 142 | * we are assuming that it was caused while
|
| 143 | * trying to write a master node.
|
| 144 |
|
| 145 | goto out_err;
|
| 146 | }
|
| 147 | if (ret == SCANNED_A_NODE) {
|
| 148 | struct ubifs_ch *ch = buf;
|
| 149 |
|
| 150 | if (ch->node_type != UBIFS_MST_NODE)
|
| 151 | goto out_err;
|
| 152 | dbg_rcvry("found a master node at %d:%d", lnum, offs);
|
| 153 | *mst = buf;
|
| 154 | offs += sz;
|
| 155 | buf += sz;
|
| 156 | len -= sz;
|
| 157 | }
|
| 158 | }
|
| 159 |
|
| 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 |
|
| 170 | if (offs < c->leb_size)
|
| 171 | if (!is_empty(buf, len))
|
| 172 | goto out_err;
|
| 173 | *pbuf = sbuf;
|
| 174 | return 0;
|
| 175 |
|
| 176 | out_err:
|
| 177 | err = -EINVAL;
|
| 178 | out_free:
|
| 179 | vfree(sbuf);
|
| 180 | *mst = NULL;
|
| 181 | *cor = NULL;
|
| 182 | return err;
|
| 183 | }
|
| 184 |
|
| 185 | |
| 186 | * write_rcvrd_mst_node - write recovered master node.
|
| 187 | * @c: UBIFS file-system description object
|
| 188 | * @mst: master node
|
| 189 | *
|
| 190 | * This function returns %0 on success and a negative error code on failure.
|
| 191 |
|
| 192 | static int write_rcvrd_mst_node(struct ubifs_info *c,
|
| 193 | struct ubifs_mst_node *mst)
|
| 194 | {
|
| 195 | int err = 0, lnum = UBIFS_MST_LNUM, sz = c->mst_node_alsz;
|
| 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, mst, UBIFS_MST_NODE_SZ,
|
| 204 | offsetof(struct ubifs_mst_node, hmac), 1);
|
| 205 | if (err)
|
| 206 | goto out;
|
| 207 | err = ubifs_leb_change(c, lnum, mst, sz);
|
| 208 | if (err)
|
| 209 | goto out;
|
| 210 | err = ubifs_leb_change(c, lnum + 1, mst, 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, &buf1, &mst1, &cor1);
|
| 237 | if (err)
|
| 238 | goto out_free;
|
| 239 |
|
| 240 | err = get_master_node(c, UBIFS_MST_LNUM + 1, &buf2, &mst2, &cor2);
|
| 241 | if (err)
|
| 242 | goto out_free;
|
| 243 |
|
| 244 | if (mst1) {
|
| 245 | offs1 = (void *)mst1 - buf1;
|
| 246 | if ((le32_to_cpu(mst1->flags) & UBIFS_MST_RCVRY) &&
|
| 247 | (offs1 == 0 && !cor1)) {
|
| 248 | |
| 249 | * mst1 was written by recovery at offset 0 with no
|
| 250 | * corruption.
|
| 251 |
|
| 252 | dbg_rcvry("recovery recovery");
|
| 253 | mst = mst1;
|
| 254 | } else if (mst2) {
|
| 255 | offs2 = (void *)mst2 - buf2;
|
| 256 | if (offs1 == offs2) {
|
| 257 |
|
| 258 | if (ubifs_compare_master_node(c, mst1, mst2))
|
| 259 | goto out_err;
|
| 260 | mst = mst1;
|
| 261 | } else if (offs2 + sz == offs1) {
|
| 262 |
|
| 263 | if (cor1)
|
| 264 | goto out_err;
|
| 265 | mst = mst1;
|
| 266 | } else if (offs1 == 0 &&
|
| 267 | c->leb_size - offs2 - sz < sz) {
|
| 268 |
|
| 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, "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 |
|
| 304 | c->rcvrd_mst_node = kmalloc(sz, GFP_KERNEL);
|
| 305 | if (!c->rcvrd_mst_node) {
|
| 306 | err = -ENOMEM;
|
| 307 | goto out_free;
|
| 308 | }
|
| 309 | memcpy(c->rcvrd_mst_node, c->mst_node, UBIFS_MST_NODE_SZ);
|
| 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 |
|
| 338 | c->max_sqnum = le64_to_cpu(mst->ch.sqnum) - 1;
|
| 339 | err = write_rcvrd_mst_node(c, c->mst_node);
|
| 340 | if (err)
|
| 341 | goto out_free;
|
| 342 | }
|
| 343 |
|
| 344 | vfree(buf2);
|
| 345 | vfree(buf1);
|
| 346 |
|
| 347 | return 0;
|
| 348 |
|
| 349 | out_err:
|
| 350 | err = -EINVAL;
|
| 351 | out_free:
|
| 352 | ubifs_err(c, "failed to recover master node");
|
| 353 | if (mst1) {
|
| 354 | ubifs_err(c, "dumping first master node");
|
| 355 | ubifs_dump_node(c, mst1, c->leb_size - ((void *)mst1 - buf1));
|
| 356 | }
|
| 357 | if (mst2) {
|
| 358 | ubifs_err(c, "dumping second master node");
|
| 359 | ubifs_dump_node(c, mst2, c->leb_size - ((void *)mst2 - buf2));
|
| 360 | }
|
| 361 | vfree(buf2);
|
| 362 | vfree(buf1);
|
| 363 | return err;
|
| 364 | }
|
| 365 |
|
| 366 | |
| 367 | * ubifs_write_rcvrd_mst_node - write the recovered master node.
|
| 368 | * @c: UBIFS file-system description object
|
| 369 | *
|
| 370 | * This function writes the master node that was recovered during mounting in
|
| 371 | * read-only mode and must now be written because we are remounting rw.
|
| 372 | *
|
| 373 | * This function returns %0 on success and a negative error code on failure.
|
| 374 |
|
| 375 | int ubifs_write_rcvrd_mst_node(struct ubifs_info *c)
|
| 376 | {
|
| 377 | int err;
|
| 378 |
|
| 379 | if (!c->rcvrd_mst_node)
|
| 380 | return 0;
|
| 381 | c->rcvrd_mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
|
| 382 | c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
|
| 383 | err = write_rcvrd_mst_node(c, c->rcvrd_mst_node);
|
| 384 | if (err)
|
| 385 | return err;
|
| 386 | kfree(c->rcvrd_mst_node);
|
| 387 | c->rcvrd_mst_node = NULL;
|
| 388 | return 0;
|
| 389 | }
|
| 390 |
|
| 391 | |
| 392 | * is_last_write - determine if an offset was in the last write to a LEB.
|
| 393 | * @c: UBIFS file-system description object
|
| 394 | * @buf: buffer to check
|
| 395 | * @offs: offset to check
|
| 396 | *
|
| 397 | * This function returns %1 if @offs was in the last write to the LEB whose data
|
| 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(p, 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, 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 |
|
| 465 | skip = ALIGN(offs + UBIFS_CH_SZ, c->max_write_size) - offs;
|
| 466 | if (is_empty(buf + skip, len - skip))
|
| 467 | return 1;
|
| 468 | |
| 469 | * The area after the common header size is not empty, so the common
|
| 470 | * header must be intact. Check it.
|
| 471 |
|
| 472 | if (ubifs_check_node(c, buf, len, lnum, offs, 1, 0) != -EUCLEAN) {
|
| 473 | dbg_rcvry("unexpected bad common header at %d:%d", lnum, offs);
|
| 474 | return 0;
|
| 475 | }
|
| 476 |
|
| 477 | skip = ALIGN(offs + dlen, c->max_write_size) - offs;
|
| 478 |
|
| 479 | if (is_empty(buf + skip, len - skip))
|
| 480 | return 1;
|
| 481 | dbg_rcvry("unexpected data at %d:%d", lnum, offs + skip);
|
| 482 | return 0;
|
| 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 |
|
| 497 | if (!list_empty(&sleb->nodes)) {
|
| 498 | struct ubifs_scan_node *snod;
|
| 499 |
|
| 500 | snod = list_entry(sleb->nodes.prev,
|
| 501 | struct ubifs_scan_node, list);
|
| 502 | endpt = snod->offs + snod->len;
|
| 503 | }
|
| 504 |
|
| 505 | if (c->ro_mount && !c->remounting_rw) {
|
| 506 |
|
| 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_obj(struct ubifs_unclean_leb, GFP_NOFS);
|
| 512 | if (!ucleb)
|
| 513 | return -ENOMEM;
|
| 514 | ucleb->lnum = lnum;
|
| 515 | ucleb->endpt = endpt;
|
| 516 | list_add_tail(&ucleb->list, &c->unclean_leb_list);
|
| 517 | } else {
|
| 518 |
|
| 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, sleb->buf, 0,
|
| 532 | start, 1);
|
| 533 | if (err)
|
| 534 | return err;
|
| 535 | }
|
| 536 |
|
| 537 | if (len > endpt) {
|
| 538 | int pad_len = len - ALIGN(endpt, 8);
|
| 539 |
|
| 540 | if (pad_len > 0) {
|
| 541 | void *buf = sleb->buf + len - pad_len;
|
| 542 |
|
| 543 | ubifs_pad(c, buf, pad_len);
|
| 544 | }
|
| 545 | }
|
| 546 | err = ubifs_leb_change(c, lnum, 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(&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(&snod->list);
|
| 578 | kfree(snod);
|
| 579 | sleb->nodes_cnt -= 1;
|
| 580 | }
|
| 581 | }
|
| 582 |
|
| 583 | |
| 584 | * drop_last_node - drop the last node.
|
| 585 | * @sleb: scanned LEB information
|
| 586 | * @offs: offset of dropped nodes is returned here
|
| 587 | *
|
| 588 | * This is a helper function for 'ubifs_recover_leb()' which drops the last
|
| 589 | * node of the scanned LEB.
|
| 590 |
|
| 591 | static void drop_last_node(struct ubifs_scan_leb *sleb, int *offs)
|
| 592 | {
|
| 593 | struct ubifs_scan_node *snod;
|
| 594 |
|
| 595 | if (!list_empty(&sleb->nodes)) {
|
| 596 | snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
|
| 597 | list);
|
| 598 |
|
| 599 | dbg_rcvry("dropping last node at %d:%d",
|
| 600 | sleb->lnum, snod->offs);
|
| 601 | *offs = snod->offs;
|
| 602 | list_del(&snod->list);
|
| 603 | kfree(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(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, 1);
|
| 648 | if (ret == SCANNED_A_NODE) {
|
| 649 |
|
| 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 |
|
| 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, "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, "corrupt empty space LEB %d:%d, corruption starts at %d",
|
| 694 | lnum, offs, corruption);
|
| 695 |
|
| 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);
|
| 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);
|
| 763 | }
|
| 764 |
|
| 765 | buf = sbuf + offs;
|
| 766 | len = c->leb_size - offs;
|
| 767 |
|
| 768 | clean_buf(c, &buf, lnum, &offs, &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 |
|
| 779 | ubifs_err(c, "corruption %d", ret);
|
| 780 | ubifs_scan_a_node(c, buf, len, lnum, offs, 0);
|
| 781 | corrupted:
|
| 782 | ubifs_scanned_corruption(c, lnum, offs, buf);
|
| 783 | err = -EUCLEAN;
|
| 784 | error:
|
| 785 | ubifs_err(c, "LEB %d scanning failed", lnum);
|
| 786 | ubifs_scan_destroy(sleb);
|
| 787 | return ERR_PTR(err);
|
| 788 | }
|
| 789 |
|
| 790 | |
| 791 | * get_cs_sqnum - get commit start sequence number.
|
| 792 | * @c: UBIFS file-system description object
|
| 793 | * @lnum: LEB number of commit start node
|
| 794 | * @offs: offset of commit start node
|
| 795 | * @cs_sqnum: commit start sequence number is returned here
|
| 796 | *
|
| 797 | * This function returns %0 on success and a negative error code on failure.
|
| 798 |
|
| 799 | static int get_cs_sqnum(struct ubifs_info *c, int lnum, int offs,
|
| 800 | unsigned long long *cs_sqnum)
|
| 801 | {
|
| 802 | struct ubifs_cs_node *cs_node = NULL;
|
| 803 | int err, ret;
|
| 804 |
|
| 805 | dbg_rcvry("at %d:%d", lnum, offs);
|
| 806 | cs_node = kmalloc(UBIFS_CS_NODE_SZ, GFP_KERNEL);
|
| 807 | if (!cs_node)
|
| 808 | return -ENOMEM;
|
| 809 | if (c->leb_size - offs < UBIFS_CS_NODE_SZ)
|
| 810 | goto out_err;
|
| 811 | err = ubifs_leb_read(c, lnum, (void *)cs_node, offs,
|
| 812 | UBIFS_CS_NODE_SZ, 0);
|
| 813 | if (err && err != -EBADMSG)
|
| 814 | goto out_free;
|
| 815 | ret = ubifs_scan_a_node(c, cs_node, UBIFS_CS_NODE_SZ, lnum, offs, 0);
|
| 816 | if (ret != SCANNED_A_NODE) {
|
| 817 | ubifs_err(c, "Not a valid node");
|
| 818 | goto out_err;
|
| 819 | }
|
| 820 | if (cs_node->ch.node_type != UBIFS_CS_NODE) {
|
| 821 | ubifs_err(c, "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, "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(cs_node);
|
| 833 | return 0;
|
| 834 |
|
| 835 | out_err:
|
| 836 | err = -EINVAL;
|
| 837 | out_free:
|
| 838 | ubifs_err(c, "failed to get CS sqnum");
|
| 839 | kfree(cs_node);
|
| 840 | return err;
|
| 841 | }
|
| 842 |
|
| 843 | |
| 844 | * ubifs_recover_log_leb - scan and recover a log LEB.
|
| 845 | * @c: UBIFS file-system description object
|
| 846 | * @lnum: LEB number
|
| 847 | * @offs: offset
|
| 848 | * @sbuf: LEB-sized buffer to use
|
| 849 | *
|
| 850 | * This function does a scan of a LEB, but caters for errors that might have
|
| 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, next_lnum, 0, sbuf, 0);
|
| 872 | if (IS_ERR(sleb))
|
| 873 | return sleb;
|
| 874 | if (sleb->nodes_cnt) {
|
| 875 | struct ubifs_scan_node *snod;
|
| 876 | unsigned long long cs_sqnum = c->cs_sqnum;
|
| 877 |
|
| 878 | snod = list_entry(sleb->nodes.next,
|
| 879 | struct ubifs_scan_node, list);
|
| 880 | if (cs_sqnum == 0) {
|
| 881 | int err;
|
| 882 |
|
| 883 | err = get_cs_sqnum(c, lnum, offs, &cs_sqnum);
|
| 884 | if (err) {
|
| 885 | ubifs_scan_destroy(sleb);
|
| 886 | return ERR_PTR(err);
|
| 887 | }
|
| 888 | }
|
| 889 | if (snod->sqnum > cs_sqnum) {
|
| 890 | ubifs_err(c, "unrecoverable log corruption in LEB %d",
|
| 891 | lnum);
|
| 892 | ubifs_scan_destroy(sleb);
|
| 893 | return ERR_PTR(-EUCLEAN);
|
| 894 | }
|
| 895 | }
|
| 896 | ubifs_scan_destroy(sleb);
|
| 897 | }
|
| 898 | return ubifs_recover_leb(c, lnum, offs, sbuf, -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 |
|
| 923 | err = ubifs_leb_read(c, lnum, sbuf, offs, len, 1);
|
| 924 | if (err || !is_empty(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, sbuf, 0, offs, 1);
|
| 929 | if (err)
|
| 930 | return err;
|
| 931 | return ubifs_leb_change(c, lnum, sbuf, 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, c->ihead_lnum, c->ihead_offs, sbuf);
|
| 962 | if (err)
|
| 963 | return err;
|
| 964 |
|
| 965 | dbg_rcvry("checking LPT head at %d:%d", c->nhead_lnum, c->nhead_offs);
|
| 966 |
|
| 967 | return recover_head(c, c->nhead_lnum, 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 |
|
| 992 | return ubifs_leb_unmap(c, lnum);
|
| 993 | }
|
| 994 |
|
| 995 | err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
|
| 996 | if (err && err != -EBADMSG)
|
| 997 | return err;
|
| 998 |
|
| 999 | while (len >= 8) {
|
| 1000 | int ret;
|
| 1001 |
|
| 1002 | cond_resched();
|
| 1003 |
|
| 1004 |
|
| 1005 | ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
|
| 1006 |
|
| 1007 | if (ret == SCANNED_A_NODE) {
|
| 1008 |
|
| 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 |
|
| 1021 | offs += ret;
|
| 1022 | buf += ret;
|
| 1023 | len -= ret;
|
| 1024 | continue;
|
| 1025 | }
|
| 1026 |
|
| 1027 | if (ret == SCANNED_EMPTY_SPACE) {
|
| 1028 | ubifs_err(c, "unexpected empty space at %d:%d",
|
| 1029 | lnum, offs);
|
| 1030 | return -EUCLEAN;
|
| 1031 | }
|
| 1032 |
|
| 1033 | if (quiet) {
|
| 1034 |
|
| 1035 | quiet = 0;
|
| 1036 | continue;
|
| 1037 | }
|
| 1038 |
|
| 1039 | ubifs_scanned_corruption(c, lnum, offs, buf);
|
| 1040 | return -EUCLEAN;
|
| 1041 | }
|
| 1042 |
|
| 1043 |
|
| 1044 | len = ALIGN(ucleb->endpt, c->min_io_size);
|
| 1045 | if (len > ucleb->endpt) {
|
| 1046 | int pad_len = len - ALIGN(ucleb->endpt, 8);
|
| 1047 |
|
| 1048 | if (pad_len > 0) {
|
| 1049 | buf = c->sbuf + len - pad_len;
|
| 1050 | ubifs_pad(c, buf, pad_len);
|
| 1051 | }
|
| 1052 | }
|
| 1053 |
|
| 1054 |
|
| 1055 | err = ubifs_leb_change(c, lnum, 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(&c->unclean_leb_list)) {
|
| 1079 | struct ubifs_unclean_leb *ucleb;
|
| 1080 | int err;
|
| 1081 |
|
| 1082 | ucleb = list_entry(c->unclean_leb_list.next,
|
| 1083 | struct ubifs_unclean_leb, list);
|
| 1084 | err = clean_an_unclean_leb(c, ucleb, sbuf);
|
| 1085 | if (err)
|
| 1086 | return err;
|
| 1087 | list_del(&ucleb->list);
|
| 1088 | kfree(ucleb);
|
| 1089 | }
|
| 1090 | return 0;
|
| 1091 | }
|
| 1092 |
|
| 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, "could not find an empty LEB");
|
| 1123 | ubifs_dump_lprops(c);
|
| 1124 | ubifs_dump_budg(c, &c->bi);
|
| 1125 | return lnum;
|
| 1126 | }
|
| 1127 |
|
| 1128 |
|
| 1129 | err = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
|
| 1130 | LPROPS_INDEX, 0);
|
| 1131 | if (err)
|
| 1132 | return err;
|
| 1133 |
|
| 1134 | c->gc_lnum = lnum;
|
| 1135 | dbg_rcvry("found empty LEB %d, run commit", lnum);
|
| 1136 |
|
| 1137 | return ubifs_run_commit(c);
|
| 1138 | }
|
| 1139 |
|
| 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, &lp, wbuf->offs, 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(&wbuf->io_mutex, wbuf->jhead);
|
| 1193 | err = ubifs_garbage_collect_leb(c, &lp);
|
| 1194 | if (err >= 0) {
|
| 1195 | int err2 = ubifs_wbuf_sync_nolock(wbuf);
|
| 1196 |
|
| 1197 | if (err2)
|
| 1198 | err = err2;
|
| 1199 | }
|
| 1200 | mutex_unlock(&wbuf->io_mutex);
|
| 1201 | if (err < 0) {
|
| 1202 | ubifs_err(c, "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, 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_obj(struct size_entry);
|
| 1262 | if (!e)
|
| 1263 | return -ENOMEM;
|
| 1264 |
|
| 1265 | e->inum = inum;
|
| 1266 | e->i_size = i_size;
|
| 1267 | e->d_size = d_size;
|
| 1268 | e->exists = exists;
|
| 1269 |
|
| 1270 | rb_link_node(&e->rb, parent, p);
|
| 1271 | rb_insert_color(&e->rb, &c->size_tree);
|
| 1272 |
|
| 1273 | return 0;
|
| 1274 | }
|
| 1275 |
|
| 1276 | |
| 1277 | * find_ino - find an entry on the size tree.
|
| 1278 | * @c: UBIFS file-system description object
|
| 1279 | * @inum: inode number
|
| 1280 |
|
| 1281 | static struct size_entry *find_ino(struct ubifs_info *c, ino_t inum)
|
| 1282 | {
|
| 1283 | struct rb_node *p = c->size_tree.rb_node;
|
| 1284 | struct size_entry *e;
|
| 1285 |
|
| 1286 | while (p) {
|
| 1287 | e = rb_entry(p, struct size_entry, rb);
|
| 1288 | if (inum < e->inum)
|
| 1289 | p = p->rb_left;
|
| 1290 | else if (inum > e->inum)
|
| 1291 | p = p->rb_right;
|
| 1292 | else
|
| 1293 | return e;
|
| 1294 | }
|
| 1295 | return NULL;
|
| 1296 | }
|
| 1297 |
|
| 1298 | |
| 1299 | * remove_ino - remove an entry from the size tree.
|
| 1300 | * @c: UBIFS file-system description object
|
| 1301 | * @inum: inode number
|
| 1302 |
|
| 1303 | static void remove_ino(struct ubifs_info *c, ino_t inum)
|
| 1304 | {
|
| 1305 | struct size_entry *e = find_ino(c, inum);
|
| 1306 |
|
| 1307 | if (!e)
|
| 1308 | return;
|
| 1309 | rb_erase(&e->rb, &c->size_tree);
|
| 1310 | kfree(e);
|
| 1311 | }
|
| 1312 |
|
| 1313 | |
| 1314 | * ubifs_destroy_size_tree - free resources related to the size tree.
|
| 1315 | * @c: UBIFS file-system description object
|
| 1316 |
|
| 1317 | void ubifs_destroy_size_tree(struct ubifs_info *c)
|
| 1318 | {
|
| 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(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, key);
|
| 1358 | struct size_entry *e;
|
| 1359 | int err;
|
| 1360 |
|
| 1361 | switch (key_type(c, key)) {
|
| 1362 | case UBIFS_INO_KEY:
|
| 1363 | if (deletion)
|
| 1364 | remove_ino(c, inum);
|
| 1365 | else {
|
| 1366 | e = find_ino(c, inum);
|
| 1367 | if (e) {
|
| 1368 | e->i_size = new_size;
|
| 1369 | e->exists = 1;
|
| 1370 | } else {
|
| 1371 | err = add_ino(c, inum, new_size, 0, 1);
|
| 1372 | if (err)
|
| 1373 | return err;
|
| 1374 | }
|
| 1375 | }
|
| 1376 | break;
|
| 1377 | case UBIFS_DATA_KEY:
|
| 1378 | e = find_ino(c, inum);
|
| 1379 | if (e) {
|
| 1380 | if (new_size > e->d_size)
|
| 1381 | e->d_size = new_size;
|
| 1382 | } else {
|
| 1383 | err = add_ino(c, inum, 0, new_size, 0);
|
| 1384 | if (err)
|
| 1385 | return err;
|
| 1386 | }
|
| 1387 | break;
|
| 1388 | case UBIFS_TRUN_KEY:
|
| 1389 | e = find_ino(c, inum);
|
| 1390 | if (e)
|
| 1391 | e->d_size = new_size;
|
| 1392 | break;
|
| 1393 | }
|
| 1394 | return 0;
|
| 1395 | }
|
| 1396 |
|
| 1397 | |
| 1398 | * fix_size_in_place - fix inode size in place on flash.
|
| 1399 | * @c: UBIFS file-system description object
|
| 1400 | * @e: inode size information for recovery
|
| 1401 |
|
| 1402 | static int fix_size_in_place(struct ubifs_info *c, struct size_entry *e)
|
| 1403 | {
|
| 1404 | struct ubifs_ino_node *ino = c->sbuf;
|
| 1405 | unsigned char *p;
|
| 1406 | union ubifs_key key;
|
| 1407 | int err, lnum, offs, len;
|
| 1408 | loff_t i_size;
|
| 1409 |
|
| 1410 |
|
| 1411 | ino_key_init(c, &key, e->inum);
|
| 1412 | err = ubifs_tnc_locate(c, &key, ino, &lnum, &offs);
|
| 1413 | if (err)
|
| 1414 | goto out;
|
| 1415 | |
| 1416 | * If the size recorded on the inode node is greater than the size that
|
| 1417 | * was calculated from nodes in the journal then don't change the inode.
|
| 1418 |
|
| 1419 | i_size = le64_to_cpu(ino->size);
|
| 1420 | if (i_size >= e->d_size)
|
| 1421 | return 0;
|
| 1422 |
|
| 1423 | err = ubifs_leb_read(c, lnum, c->sbuf, 0, c->leb_size, 1);
|
| 1424 | if (err)
|
| 1425 | goto out;
|
| 1426 |
|
| 1427 | ino = c->sbuf + offs;
|
| 1428 | ino->size = cpu_to_le64(e->d_size);
|
| 1429 | len = le32_to_cpu(ino->ch.len);
|
| 1430 | ubifs_crc_node((void *)ino, len);
|
| 1431 |
|
| 1432 | p = c->sbuf;
|
| 1433 | len = c->leb_size - 1;
|
| 1434 | while (p[len] == 0xff)
|
| 1435 | len -= 1;
|
| 1436 | len = ALIGN(len + 1, c->min_io_size);
|
| 1437 |
|
| 1438 | err = ubifs_leb_change(c, lnum, c->sbuf, len);
|
| 1439 | if (err)
|
| 1440 | goto out;
|
| 1441 | dbg_rcvry("inode %lu at %d:%d size %lld -> %lld",
|
| 1442 | (unsigned long)e->inum, lnum, offs, i_size, e->d_size);
|
| 1443 | return 0;
|
| 1444 |
|
| 1445 | out:
|
| 1446 | ubifs_warn(c, "inode %lu failed to fix size %lld -> %lld error %d",
|
| 1447 | (unsigned long)e->inum, e->i_size, e->d_size, err);
|
| 1448 | return err;
|
| 1449 | }
|
| 1450 |
|
| 1451 | |
| 1452 | * inode_fix_size - fix inode size
|
| 1453 | * @c: UBIFS file-system description object
|
| 1454 | * @e: inode size information for recovery
|
| 1455 |
|
| 1456 | static int inode_fix_size(struct ubifs_info *c, struct size_entry *e)
|
| 1457 | {
|
| 1458 | struct inode *inode;
|
| 1459 | struct ubifs_inode *ui;
|
| 1460 | int err;
|
| 1461 |
|
| 1462 | if (c->ro_mount)
|
| 1463 | ubifs_assert(c, !e->inode);
|
| 1464 |
|
| 1465 | if (e->inode) {
|
| 1466 |
|
| 1467 | inode = e->inode;
|
| 1468 | } else {
|
| 1469 | inode = ubifs_iget(c->vfs_sb, e->inum);
|
| 1470 | if (IS_ERR(inode))
|
| 1471 | return PTR_ERR(inode);
|
| 1472 |
|
| 1473 | if (inode->i_size >= e->d_size) {
|
| 1474 | |
| 1475 | * The original inode in the index already has a size
|
| 1476 | * big enough, nothing to do
|
| 1477 |
|
| 1478 | iput(inode);
|
| 1479 | return 0;
|
| 1480 | }
|
| 1481 |
|
| 1482 | dbg_rcvry("ino %lu size %lld -> %lld",
|
| 1483 | (unsigned long)e->inum,
|
| 1484 | inode->i_size, e->d_size);
|
| 1485 |
|
| 1486 | ui = ubifs_inode(inode);
|
| 1487 |
|
| 1488 | inode->i_size = e->d_size;
|
| 1489 | ui->ui_size = e->d_size;
|
| 1490 | ui->synced_i_size = e->d_size;
|
| 1491 |
|
| 1492 | e->inode = inode;
|
| 1493 | }
|
| 1494 |
|
| 1495 | |
| 1496 | * In readonly mode just keep the inode pinned in memory until we go
|
| 1497 | * readwrite. In readwrite mode write the inode to the journal with the
|
| 1498 | * fixed size.
|
| 1499 |
|
| 1500 | if (c->ro_mount)
|
| 1501 | return 0;
|
| 1502 |
|
| 1503 | err = ubifs_jnl_write_inode(c, inode);
|
| 1504 |
|
| 1505 | iput(inode);
|
| 1506 |
|
| 1507 | if (err)
|
| 1508 | return err;
|
| 1509 |
|
| 1510 | rb_erase(&e->rb, &c->size_tree);
|
| 1511 | kfree(e);
|
| 1512 |
|
| 1513 | return 0;
|
| 1514 | }
|
| 1515 |
|
| 1516 | |
| 1517 | * ubifs_recover_size - recover inode size.
|
| 1518 | * @c: UBIFS file-system description object
|
| 1519 | * @in_place: If true, do a in-place size fixup
|
| 1520 | *
|
| 1521 | * This function attempts to fix inode size discrepancies identified by the
|
| 1522 | * 'ubifs_recover_size_accum()' function.
|
| 1523 | *
|
| 1524 | * This functions returns %0 on success and a negative error code on failure.
|
| 1525 |
|
| 1526 | int ubifs_recover_size(struct ubifs_info *c, bool in_place)
|
| 1527 | {
|
| 1528 | struct rb_node *this = rb_first(&c->size_tree);
|
| 1529 |
|
| 1530 | while (this) {
|
| 1531 | struct size_entry *e;
|
| 1532 | int err;
|
| 1533 |
|
| 1534 | e = rb_entry(this, struct size_entry, rb);
|
| 1535 |
|
| 1536 | this = rb_next(this);
|
| 1537 |
|
| 1538 | if (!e->exists) {
|
| 1539 | union ubifs_key key;
|
| 1540 |
|
| 1541 | ino_key_init(c, &key, e->inum);
|
| 1542 | err = ubifs_tnc_lookup(c, &key, c->sbuf);
|
| 1543 | if (err && err != -ENOENT)
|
| 1544 | return err;
|
| 1545 | if (err == -ENOENT) {
|
| 1546 |
|
| 1547 | dbg_rcvry("removing ino %lu",
|
| 1548 | (unsigned long)e->inum);
|
| 1549 | err = ubifs_tnc_remove_ino(c, e->inum);
|
| 1550 | if (err)
|
| 1551 | return err;
|
| 1552 | } else {
|
| 1553 | struct ubifs_ino_node *ino = c->sbuf;
|
| 1554 |
|
| 1555 | e->exists = 1;
|
| 1556 | e->i_size = le64_to_cpu(ino->size);
|
| 1557 | }
|
| 1558 | }
|
| 1559 |
|
| 1560 | if (e->exists && e->i_size < e->d_size) {
|
| 1561 | ubifs_assert(c, !(c->ro_mount && in_place));
|
| 1562 |
|
| 1563 | |
| 1564 | * We found data that is outside the found inode size,
|
| 1565 | * fixup the inode size
|
| 1566 |
|
| 1567 |
|
| 1568 | if (in_place) {
|
| 1569 | err = fix_size_in_place(c, e);
|
| 1570 | if (err)
|
| 1571 | return err;
|
| 1572 | iput(e->inode);
|
| 1573 | } else {
|
| 1574 | err = inode_fix_size(c, e);
|
| 1575 | if (err)
|
| 1576 | return err;
|
| 1577 | continue;
|
| 1578 | }
|
| 1579 | }
|
| 1580 |
|
| 1581 | rb_erase(&e->rb, &c->size_tree);
|
| 1582 | kfree(e);
|
| 1583 | }
|
| 1584 |
|
| 1585 | return 0;
|
| 1586 | }
|