1 /* 2 * This file is part of UBIFS. 3 * 4 * Copyright (C) 2006-2008 Nokia Corporation. 5 * Copyright (C) 2006, 2007 University of Szeged, Hungary 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 as published by 9 * the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 14 * more details. 15 * 16 * You should have received a copy of the GNU General Public License along with 17 * this program; if not, write to the Free Software Foundation, Inc., 51 18 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 19 * 20 * Authors: Artem Bityutskiy (Битюцкий Артём) 21 * Adrian Hunter 22 * Zoltan Sogor 23 */ 24 25 /* 26 * This file implements UBIFS I/O subsystem which provides various I/O-related 27 * helper functions (reading/writing/checking/validating nodes) and implements 28 * write-buffering support. Write buffers help to save space which otherwise 29 * would have been wasted for padding to the nearest minimal I/O unit boundary. 30 * Instead, data first goes to the write-buffer and is flushed when the 31 * buffer is full or when it is not used for some time (by timer). This is 32 * similar to the mechanism is used by JFFS2. 33 * 34 * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by 35 * mutexes defined inside these objects. Since sometimes upper-level code 36 * has to lock the write-buffer (e.g. journal space reservation code), many 37 * functions related to write-buffers have "nolock" suffix which means that the 38 * caller has to lock the write-buffer before calling this function. 39 * 40 * UBIFS stores nodes at 64 bit-aligned addresses. If the node length is not 41 * aligned, UBIFS starts the next node from the aligned address, and the padded 42 * bytes may contain any rubbish. In other words, UBIFS does not put padding 43 * bytes in those small gaps. Common headers of nodes store real node lengths, 44 * not aligned lengths. Indexing nodes also store real lengths in branches. 45 * 46 * UBIFS uses padding when it pads to the next min. I/O unit. In this case it 47 * uses padding nodes or padding bytes, if the padding node does not fit. 48 * 49 * All UBIFS nodes are protected by CRC checksums and UBIFS checks all nodes 50 * every time they are read from the flash media. 51 */ 52 53 #include <linux/crc32.h> 54 #include "ubifs.h" 55 56 /** 57 * ubifs_ro_mode - switch UBIFS to read read-only mode. 58 * @c: UBIFS file-system description object 59 * @err: error code which is the reason of switching to R/O mode 60 */ 61 void ubifs_ro_mode(struct ubifs_info *c, int err) 62 { 63 if (!c->ro_media) { 64 c->ro_media = 1; 65 c->no_chk_data_crc = 0; 66 ubifs_warn("switched to read-only mode, error %d", err); 67 dbg_dump_stack(); 68 } 69 } 70 71 /** 72 * ubifs_check_node - check node. 73 * @c: UBIFS file-system description object 74 * @buf: node to check 75 * @lnum: logical eraseblock number 76 * @offs: offset within the logical eraseblock 77 * @quiet: print no messages 78 * @must_chk_crc: indicates whether to always check the CRC 79 * 80 * This function checks node magic number and CRC checksum. This function also 81 * validates node length to prevent UBIFS from becoming crazy when an attacker 82 * feeds it a file-system image with incorrect nodes. For example, too large 83 * node length in the common header could cause UBIFS to read memory outside of 84 * allocated buffer when checking the CRC checksum. 85 * 86 * This function may skip data nodes CRC checking if @c->no_chk_data_crc is 87 * true, which is controlled by corresponding UBIFS mount option. However, if 88 * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is 89 * checked. Similarly, if @c->always_chk_crc is true, @c->no_chk_data_crc is 90 * ignored and CRC is checked. 91 * 92 * This function returns zero in case of success and %-EUCLEAN in case of bad 93 * CRC or magic. 94 */ 95 int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum, 96 int offs, int quiet, int must_chk_crc) 97 { 98 int err = -EINVAL, type, node_len; 99 uint32_t crc, node_crc, magic; 100 const struct ubifs_ch *ch = buf; 101 102 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0); 103 ubifs_assert(!(offs & 7) && offs < c->leb_size); 104 105 magic = le32_to_cpu(ch->magic); 106 if (magic != UBIFS_NODE_MAGIC) { 107 if (!quiet) 108 ubifs_err("bad magic %#08x, expected %#08x", 109 magic, UBIFS_NODE_MAGIC); 110 err = -EUCLEAN; 111 goto out; 112 } 113 114 type = ch->node_type; 115 if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) { 116 if (!quiet) 117 ubifs_err("bad node type %d", type); 118 goto out; 119 } 120 121 node_len = le32_to_cpu(ch->len); 122 if (node_len + offs > c->leb_size) 123 goto out_len; 124 125 if (c->ranges[type].max_len == 0) { 126 if (node_len != c->ranges[type].len) 127 goto out_len; 128 } else if (node_len < c->ranges[type].min_len || 129 node_len > c->ranges[type].max_len) 130 goto out_len; 131 132 if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc && 133 c->no_chk_data_crc) 134 return 0; 135 136 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8); 137 node_crc = le32_to_cpu(ch->crc); 138 if (crc != node_crc) { 139 if (!quiet) 140 ubifs_err("bad CRC: calculated %#08x, read %#08x", 141 crc, node_crc); 142 err = -EUCLEAN; 143 goto out; 144 } 145 146 return 0; 147 148 out_len: 149 if (!quiet) 150 ubifs_err("bad node length %d", node_len); 151 out: 152 if (!quiet) { 153 ubifs_err("bad node at LEB %d:%d", lnum, offs); 154 dbg_dump_node(c, buf); 155 dbg_dump_stack(); 156 } 157 return err; 158 } 159 160 /** 161 * ubifs_pad - pad flash space. 162 * @c: UBIFS file-system description object 163 * @buf: buffer to put padding to 164 * @pad: how many bytes to pad 165 * 166 * The flash media obliges us to write only in chunks of %c->min_io_size and 167 * when we have to write less data we add padding node to the write-buffer and 168 * pad it to the next minimal I/O unit's boundary. Padding nodes help when the 169 * media is being scanned. If the amount of wasted space is not enough to fit a 170 * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes 171 * pattern (%UBIFS_PADDING_BYTE). 172 * 173 * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is 174 * used. 175 */ 176 void ubifs_pad(const struct ubifs_info *c, void *buf, int pad) 177 { 178 uint32_t crc; 179 180 ubifs_assert(pad >= 0 && !(pad & 7)); 181 182 if (pad >= UBIFS_PAD_NODE_SZ) { 183 struct ubifs_ch *ch = buf; 184 struct ubifs_pad_node *pad_node = buf; 185 186 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC); 187 ch->node_type = UBIFS_PAD_NODE; 188 ch->group_type = UBIFS_NO_NODE_GROUP; 189 ch->padding[0] = ch->padding[1] = 0; 190 ch->sqnum = 0; 191 ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ); 192 pad -= UBIFS_PAD_NODE_SZ; 193 pad_node->pad_len = cpu_to_le32(pad); 194 crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8); 195 ch->crc = cpu_to_le32(crc); 196 memset(buf + UBIFS_PAD_NODE_SZ, 0, pad); 197 } else if (pad > 0) 198 /* Too little space, padding node won't fit */ 199 memset(buf, UBIFS_PADDING_BYTE, pad); 200 } 201 202 /** 203 * next_sqnum - get next sequence number. 204 * @c: UBIFS file-system description object 205 */ 206 static unsigned long long next_sqnum(struct ubifs_info *c) 207 { 208 unsigned long long sqnum; 209 210 spin_lock(&c->cnt_lock); 211 sqnum = ++c->max_sqnum; 212 spin_unlock(&c->cnt_lock); 213 214 if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) { 215 if (sqnum >= SQNUM_WATERMARK) { 216 ubifs_err("sequence number overflow %llu, end of life", 217 sqnum); 218 ubifs_ro_mode(c, -EINVAL); 219 } 220 ubifs_warn("running out of sequence numbers, end of life soon"); 221 } 222 223 return sqnum; 224 } 225 226 /** 227 * ubifs_prepare_node - prepare node to be written to flash. 228 * @c: UBIFS file-system description object 229 * @node: the node to pad 230 * @len: node length 231 * @pad: if the buffer has to be padded 232 * 233 * This function prepares node at @node to be written to the media - it 234 * calculates node CRC, fills the common header, and adds proper padding up to 235 * the next minimum I/O unit if @pad is not zero. 236 */ 237 void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad) 238 { 239 uint32_t crc; 240 struct ubifs_ch *ch = node; 241 unsigned long long sqnum = next_sqnum(c); 242 243 ubifs_assert(len >= UBIFS_CH_SZ); 244 245 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC); 246 ch->len = cpu_to_le32(len); 247 ch->group_type = UBIFS_NO_NODE_GROUP; 248 ch->sqnum = cpu_to_le64(sqnum); 249 ch->padding[0] = ch->padding[1] = 0; 250 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8); 251 ch->crc = cpu_to_le32(crc); 252 253 if (pad) { 254 len = ALIGN(len, 8); 255 pad = ALIGN(len, c->min_io_size) - len; 256 ubifs_pad(c, node + len, pad); 257 } 258 } 259 260 /** 261 * ubifs_prep_grp_node - prepare node of a group to be written to flash. 262 * @c: UBIFS file-system description object 263 * @node: the node to pad 264 * @len: node length 265 * @last: indicates the last node of the group 266 * 267 * This function prepares node at @node to be written to the media - it 268 * calculates node CRC and fills the common header. 269 */ 270 void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last) 271 { 272 uint32_t crc; 273 struct ubifs_ch *ch = node; 274 unsigned long long sqnum = next_sqnum(c); 275 276 ubifs_assert(len >= UBIFS_CH_SZ); 277 278 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC); 279 ch->len = cpu_to_le32(len); 280 if (last) 281 ch->group_type = UBIFS_LAST_OF_NODE_GROUP; 282 else 283 ch->group_type = UBIFS_IN_NODE_GROUP; 284 ch->sqnum = cpu_to_le64(sqnum); 285 ch->padding[0] = ch->padding[1] = 0; 286 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8); 287 ch->crc = cpu_to_le32(crc); 288 } 289 290 /** 291 * wbuf_timer_callback - write-buffer timer callback function. 292 * @data: timer data (write-buffer descriptor) 293 * 294 * This function is called when the write-buffer timer expires. 295 */ 296 static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer) 297 { 298 struct ubifs_wbuf *wbuf = container_of(timer, struct ubifs_wbuf, timer); 299 300 dbg_io("jhead %s", dbg_jhead(wbuf->jhead)); 301 wbuf->need_sync = 1; 302 wbuf->c->need_wbuf_sync = 1; 303 ubifs_wake_up_bgt(wbuf->c); 304 return HRTIMER_NORESTART; 305 } 306 307 /** 308 * new_wbuf_timer - start new write-buffer timer. 309 * @wbuf: write-buffer descriptor 310 */ 311 static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf) 312 { 313 ubifs_assert(!hrtimer_active(&wbuf->timer)); 314 315 if (wbuf->no_timer) 316 return; 317 dbg_io("set timer for jhead %s, %llu-%llu millisecs", 318 dbg_jhead(wbuf->jhead), 319 div_u64(ktime_to_ns(wbuf->softlimit), USEC_PER_SEC), 320 div_u64(ktime_to_ns(wbuf->softlimit) + wbuf->delta, 321 USEC_PER_SEC)); 322 hrtimer_start_range_ns(&wbuf->timer, wbuf->softlimit, wbuf->delta, 323 HRTIMER_MODE_REL); 324 } 325 326 /** 327 * cancel_wbuf_timer - cancel write-buffer timer. 328 * @wbuf: write-buffer descriptor 329 */ 330 static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf) 331 { 332 if (wbuf->no_timer) 333 return; 334 wbuf->need_sync = 0; 335 hrtimer_cancel(&wbuf->timer); 336 } 337 338 /** 339 * ubifs_wbuf_sync_nolock - synchronize write-buffer. 340 * @wbuf: write-buffer to synchronize 341 * 342 * This function synchronizes write-buffer @buf and returns zero in case of 343 * success or a negative error code in case of failure. 344 */ 345 int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf) 346 { 347 struct ubifs_info *c = wbuf->c; 348 int err, dirt; 349 350 cancel_wbuf_timer_nolock(wbuf); 351 if (!wbuf->used || wbuf->lnum == -1) 352 /* Write-buffer is empty or not seeked */ 353 return 0; 354 355 dbg_io("LEB %d:%d, %d bytes, jhead %s", 356 wbuf->lnum, wbuf->offs, wbuf->used, dbg_jhead(wbuf->jhead)); 357 ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY)); 358 ubifs_assert(!(wbuf->avail & 7)); 359 ubifs_assert(wbuf->offs + c->min_io_size <= c->leb_size); 360 361 if (c->ro_media) 362 return -EROFS; 363 364 ubifs_pad(c, wbuf->buf + wbuf->used, wbuf->avail); 365 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs, 366 c->min_io_size, wbuf->dtype); 367 if (err) { 368 ubifs_err("cannot write %d bytes to LEB %d:%d", 369 c->min_io_size, wbuf->lnum, wbuf->offs); 370 dbg_dump_stack(); 371 return err; 372 } 373 374 dirt = wbuf->avail; 375 376 spin_lock(&wbuf->lock); 377 wbuf->offs += c->min_io_size; 378 wbuf->avail = c->min_io_size; 379 wbuf->used = 0; 380 wbuf->next_ino = 0; 381 spin_unlock(&wbuf->lock); 382 383 if (wbuf->sync_callback) 384 err = wbuf->sync_callback(c, wbuf->lnum, 385 c->leb_size - wbuf->offs, dirt); 386 return err; 387 } 388 389 /** 390 * ubifs_wbuf_seek_nolock - seek write-buffer. 391 * @wbuf: write-buffer 392 * @lnum: logical eraseblock number to seek to 393 * @offs: logical eraseblock offset to seek to 394 * @dtype: data type 395 * 396 * This function targets the write-buffer to logical eraseblock @lnum:@offs. 397 * The write-buffer is synchronized if it is not empty. Returns zero in case of 398 * success and a negative error code in case of failure. 399 */ 400 int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs, 401 int dtype) 402 { 403 const struct ubifs_info *c = wbuf->c; 404 405 dbg_io("LEB %d:%d, jhead %s", lnum, offs, dbg_jhead(wbuf->jhead)); 406 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt); 407 ubifs_assert(offs >= 0 && offs <= c->leb_size); 408 ubifs_assert(offs % c->min_io_size == 0 && !(offs & 7)); 409 ubifs_assert(lnum != wbuf->lnum); 410 411 if (wbuf->used > 0) { 412 int err = ubifs_wbuf_sync_nolock(wbuf); 413 414 if (err) 415 return err; 416 } 417 418 spin_lock(&wbuf->lock); 419 wbuf->lnum = lnum; 420 wbuf->offs = offs; 421 wbuf->avail = c->min_io_size; 422 wbuf->used = 0; 423 spin_unlock(&wbuf->lock); 424 wbuf->dtype = dtype; 425 426 return 0; 427 } 428 429 /** 430 * ubifs_bg_wbufs_sync - synchronize write-buffers. 431 * @c: UBIFS file-system description object 432 * 433 * This function is called by background thread to synchronize write-buffers. 434 * Returns zero in case of success and a negative error code in case of 435 * failure. 436 */ 437 int ubifs_bg_wbufs_sync(struct ubifs_info *c) 438 { 439 int err, i; 440 441 if (!c->need_wbuf_sync) 442 return 0; 443 c->need_wbuf_sync = 0; 444 445 if (c->ro_media) { 446 err = -EROFS; 447 goto out_timers; 448 } 449 450 dbg_io("synchronize"); 451 for (i = 0; i < c->jhead_cnt; i++) { 452 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf; 453 454 cond_resched(); 455 456 /* 457 * If the mutex is locked then wbuf is being changed, so 458 * synchronization is not necessary. 459 */ 460 if (mutex_is_locked(&wbuf->io_mutex)) 461 continue; 462 463 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); 464 if (!wbuf->need_sync) { 465 mutex_unlock(&wbuf->io_mutex); 466 continue; 467 } 468 469 err = ubifs_wbuf_sync_nolock(wbuf); 470 mutex_unlock(&wbuf->io_mutex); 471 if (err) { 472 ubifs_err("cannot sync write-buffer, error %d", err); 473 ubifs_ro_mode(c, err); 474 goto out_timers; 475 } 476 } 477 478 return 0; 479 480 out_timers: 481 /* Cancel all timers to prevent repeated errors */ 482 for (i = 0; i < c->jhead_cnt; i++) { 483 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf; 484 485 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); 486 cancel_wbuf_timer_nolock(wbuf); 487 mutex_unlock(&wbuf->io_mutex); 488 } 489 return err; 490 } 491 492 /** 493 * ubifs_wbuf_write_nolock - write data to flash via write-buffer. 494 * @wbuf: write-buffer 495 * @buf: node to write 496 * @len: node length 497 * 498 * This function writes data to flash via write-buffer @wbuf. This means that 499 * the last piece of the node won't reach the flash media immediately if it 500 * does not take whole minimal I/O unit. Instead, the node will sit in RAM 501 * until the write-buffer is synchronized (e.g., by timer). 502 * 503 * This function returns zero in case of success and a negative error code in 504 * case of failure. If the node cannot be written because there is no more 505 * space in this logical eraseblock, %-ENOSPC is returned. 506 */ 507 int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len) 508 { 509 struct ubifs_info *c = wbuf->c; 510 int err, written, n, aligned_len = ALIGN(len, 8), offs; 511 512 dbg_io("%d bytes (%s) to jhead %s wbuf at LEB %d:%d", len, 513 dbg_ntype(((struct ubifs_ch *)buf)->node_type), 514 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs + wbuf->used); 515 ubifs_assert(len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt); 516 ubifs_assert(wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0); 517 ubifs_assert(!(wbuf->offs & 7) && wbuf->offs <= c->leb_size); 518 ubifs_assert(wbuf->avail > 0 && wbuf->avail <= c->min_io_size); 519 ubifs_assert(mutex_is_locked(&wbuf->io_mutex)); 520 521 if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) { 522 err = -ENOSPC; 523 goto out; 524 } 525 526 cancel_wbuf_timer_nolock(wbuf); 527 528 if (c->ro_media) 529 return -EROFS; 530 531 if (aligned_len <= wbuf->avail) { 532 /* 533 * The node is not very large and fits entirely within 534 * write-buffer. 535 */ 536 memcpy(wbuf->buf + wbuf->used, buf, len); 537 538 if (aligned_len == wbuf->avail) { 539 dbg_io("flush jhead %s wbuf to LEB %d:%d", 540 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs); 541 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, 542 wbuf->offs, c->min_io_size, 543 wbuf->dtype); 544 if (err) 545 goto out; 546 547 spin_lock(&wbuf->lock); 548 wbuf->offs += c->min_io_size; 549 wbuf->avail = c->min_io_size; 550 wbuf->used = 0; 551 wbuf->next_ino = 0; 552 spin_unlock(&wbuf->lock); 553 } else { 554 spin_lock(&wbuf->lock); 555 wbuf->avail -= aligned_len; 556 wbuf->used += aligned_len; 557 spin_unlock(&wbuf->lock); 558 } 559 560 goto exit; 561 } 562 563 /* 564 * The node is large enough and does not fit entirely within current 565 * minimal I/O unit. We have to fill and flush write-buffer and switch 566 * to the next min. I/O unit. 567 */ 568 dbg_io("flush jhead %s wbuf to LEB %d:%d", 569 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs); 570 memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail); 571 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs, 572 c->min_io_size, wbuf->dtype); 573 if (err) 574 goto out; 575 576 offs = wbuf->offs + c->min_io_size; 577 len -= wbuf->avail; 578 aligned_len -= wbuf->avail; 579 written = wbuf->avail; 580 581 /* 582 * The remaining data may take more whole min. I/O units, so write the 583 * remains multiple to min. I/O unit size directly to the flash media. 584 * We align node length to 8-byte boundary because we anyway flash wbuf 585 * if the remaining space is less than 8 bytes. 586 */ 587 n = aligned_len >> c->min_io_shift; 588 if (n) { 589 n <<= c->min_io_shift; 590 dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, offs); 591 err = ubi_leb_write(c->ubi, wbuf->lnum, buf + written, offs, n, 592 wbuf->dtype); 593 if (err) 594 goto out; 595 offs += n; 596 aligned_len -= n; 597 len -= n; 598 written += n; 599 } 600 601 spin_lock(&wbuf->lock); 602 if (aligned_len) 603 /* 604 * And now we have what's left and what does not take whole 605 * min. I/O unit, so write it to the write-buffer and we are 606 * done. 607 */ 608 memcpy(wbuf->buf, buf + written, len); 609 610 wbuf->offs = offs; 611 wbuf->used = aligned_len; 612 wbuf->avail = c->min_io_size - aligned_len; 613 wbuf->next_ino = 0; 614 spin_unlock(&wbuf->lock); 615 616 exit: 617 if (wbuf->sync_callback) { 618 int free = c->leb_size - wbuf->offs - wbuf->used; 619 620 err = wbuf->sync_callback(c, wbuf->lnum, free, 0); 621 if (err) 622 goto out; 623 } 624 625 if (wbuf->used) 626 new_wbuf_timer_nolock(wbuf); 627 628 return 0; 629 630 out: 631 ubifs_err("cannot write %d bytes to LEB %d:%d, error %d", 632 len, wbuf->lnum, wbuf->offs, err); 633 dbg_dump_node(c, buf); 634 dbg_dump_stack(); 635 dbg_dump_leb(c, wbuf->lnum); 636 return err; 637 } 638 639 /** 640 * ubifs_write_node - write node to the media. 641 * @c: UBIFS file-system description object 642 * @buf: the node to write 643 * @len: node length 644 * @lnum: logical eraseblock number 645 * @offs: offset within the logical eraseblock 646 * @dtype: node life-time hint (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN) 647 * 648 * This function automatically fills node magic number, assigns sequence 649 * number, and calculates node CRC checksum. The length of the @buf buffer has 650 * to be aligned to the minimal I/O unit size. This function automatically 651 * appends padding node and padding bytes if needed. Returns zero in case of 652 * success and a negative error code in case of failure. 653 */ 654 int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum, 655 int offs, int dtype) 656 { 657 int err, buf_len = ALIGN(len, c->min_io_size); 658 659 dbg_io("LEB %d:%d, %s, length %d (aligned %d)", 660 lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len, 661 buf_len); 662 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0); 663 ubifs_assert(offs % c->min_io_size == 0 && offs < c->leb_size); 664 665 if (c->ro_media) 666 return -EROFS; 667 668 ubifs_prepare_node(c, buf, len, 1); 669 err = ubi_leb_write(c->ubi, lnum, buf, offs, buf_len, dtype); 670 if (err) { 671 ubifs_err("cannot write %d bytes to LEB %d:%d, error %d", 672 buf_len, lnum, offs, err); 673 dbg_dump_node(c, buf); 674 dbg_dump_stack(); 675 } 676 677 return err; 678 } 679 680 /** 681 * ubifs_read_node_wbuf - read node from the media or write-buffer. 682 * @wbuf: wbuf to check for un-written data 683 * @buf: buffer to read to 684 * @type: node type 685 * @len: node length 686 * @lnum: logical eraseblock number 687 * @offs: offset within the logical eraseblock 688 * 689 * This function reads a node of known type and length, checks it and stores 690 * in @buf. If the node partially or fully sits in the write-buffer, this 691 * function takes data from the buffer, otherwise it reads the flash media. 692 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative 693 * error code in case of failure. 694 */ 695 int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len, 696 int lnum, int offs) 697 { 698 const struct ubifs_info *c = wbuf->c; 699 int err, rlen, overlap; 700 struct ubifs_ch *ch = buf; 701 702 dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs, 703 dbg_ntype(type), len, dbg_jhead(wbuf->jhead)); 704 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0); 705 ubifs_assert(!(offs & 7) && offs < c->leb_size); 706 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT); 707 708 spin_lock(&wbuf->lock); 709 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs); 710 if (!overlap) { 711 /* We may safely unlock the write-buffer and read the data */ 712 spin_unlock(&wbuf->lock); 713 return ubifs_read_node(c, buf, type, len, lnum, offs); 714 } 715 716 /* Don't read under wbuf */ 717 rlen = wbuf->offs - offs; 718 if (rlen < 0) 719 rlen = 0; 720 721 /* Copy the rest from the write-buffer */ 722 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen); 723 spin_unlock(&wbuf->lock); 724 725 if (rlen > 0) { 726 /* Read everything that goes before write-buffer */ 727 err = ubi_read(c->ubi, lnum, buf, offs, rlen); 728 if (err && err != -EBADMSG) { 729 ubifs_err("failed to read node %d from LEB %d:%d, " 730 "error %d", type, lnum, offs, err); 731 dbg_dump_stack(); 732 return err; 733 } 734 } 735 736 if (type != ch->node_type) { 737 ubifs_err("bad node type (%d but expected %d)", 738 ch->node_type, type); 739 goto out; 740 } 741 742 err = ubifs_check_node(c, buf, lnum, offs, 0, 0); 743 if (err) { 744 ubifs_err("expected node type %d", type); 745 return err; 746 } 747 748 rlen = le32_to_cpu(ch->len); 749 if (rlen != len) { 750 ubifs_err("bad node length %d, expected %d", rlen, len); 751 goto out; 752 } 753 754 return 0; 755 756 out: 757 ubifs_err("bad node at LEB %d:%d", lnum, offs); 758 dbg_dump_node(c, buf); 759 dbg_dump_stack(); 760 return -EINVAL; 761 } 762 763 /** 764 * ubifs_read_node - read node. 765 * @c: UBIFS file-system description object 766 * @buf: buffer to read to 767 * @type: node type 768 * @len: node length (not aligned) 769 * @lnum: logical eraseblock number 770 * @offs: offset within the logical eraseblock 771 * 772 * This function reads a node of known type and and length, checks it and 773 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched 774 * and a negative error code in case of failure. 775 */ 776 int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len, 777 int lnum, int offs) 778 { 779 int err, l; 780 struct ubifs_ch *ch = buf; 781 782 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len); 783 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0); 784 ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size); 785 ubifs_assert(!(offs & 7) && offs < c->leb_size); 786 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT); 787 788 err = ubi_read(c->ubi, lnum, buf, offs, len); 789 if (err && err != -EBADMSG) { 790 ubifs_err("cannot read node %d from LEB %d:%d, error %d", 791 type, lnum, offs, err); 792 return err; 793 } 794 795 if (type != ch->node_type) { 796 ubifs_err("bad node type (%d but expected %d)", 797 ch->node_type, type); 798 goto out; 799 } 800 801 err = ubifs_check_node(c, buf, lnum, offs, 0, 0); 802 if (err) { 803 ubifs_err("expected node type %d", type); 804 return err; 805 } 806 807 l = le32_to_cpu(ch->len); 808 if (l != len) { 809 ubifs_err("bad node length %d, expected %d", l, len); 810 goto out; 811 } 812 813 return 0; 814 815 out: 816 ubifs_err("bad node at LEB %d:%d", lnum, offs); 817 dbg_dump_node(c, buf); 818 dbg_dump_stack(); 819 return -EINVAL; 820 } 821 822 /** 823 * ubifs_wbuf_init - initialize write-buffer. 824 * @c: UBIFS file-system description object 825 * @wbuf: write-buffer to initialize 826 * 827 * This function initializes write-buffer. Returns zero in case of success 828 * %-ENOMEM in case of failure. 829 */ 830 int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf) 831 { 832 size_t size; 833 834 wbuf->buf = kmalloc(c->min_io_size, GFP_KERNEL); 835 if (!wbuf->buf) 836 return -ENOMEM; 837 838 size = (c->min_io_size / UBIFS_CH_SZ + 1) * sizeof(ino_t); 839 wbuf->inodes = kmalloc(size, GFP_KERNEL); 840 if (!wbuf->inodes) { 841 kfree(wbuf->buf); 842 wbuf->buf = NULL; 843 return -ENOMEM; 844 } 845 846 wbuf->used = 0; 847 wbuf->lnum = wbuf->offs = -1; 848 wbuf->avail = c->min_io_size; 849 wbuf->dtype = UBI_UNKNOWN; 850 wbuf->sync_callback = NULL; 851 mutex_init(&wbuf->io_mutex); 852 spin_lock_init(&wbuf->lock); 853 wbuf->c = c; 854 wbuf->next_ino = 0; 855 856 hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 857 wbuf->timer.function = wbuf_timer_callback_nolock; 858 wbuf->softlimit = ktime_set(WBUF_TIMEOUT_SOFTLIMIT, 0); 859 wbuf->delta = WBUF_TIMEOUT_HARDLIMIT - WBUF_TIMEOUT_SOFTLIMIT; 860 wbuf->delta *= 1000000000ULL; 861 ubifs_assert(wbuf->delta <= ULONG_MAX); 862 return 0; 863 } 864 865 /** 866 * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array. 867 * @wbuf: the write-buffer where to add 868 * @inum: the inode number 869 * 870 * This function adds an inode number to the inode array of the write-buffer. 871 */ 872 void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum) 873 { 874 if (!wbuf->buf) 875 /* NOR flash or something similar */ 876 return; 877 878 spin_lock(&wbuf->lock); 879 if (wbuf->used) 880 wbuf->inodes[wbuf->next_ino++] = inum; 881 spin_unlock(&wbuf->lock); 882 } 883 884 /** 885 * wbuf_has_ino - returns if the wbuf contains data from the inode. 886 * @wbuf: the write-buffer 887 * @inum: the inode number 888 * 889 * This function returns with %1 if the write-buffer contains some data from the 890 * given inode otherwise it returns with %0. 891 */ 892 static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum) 893 { 894 int i, ret = 0; 895 896 spin_lock(&wbuf->lock); 897 for (i = 0; i < wbuf->next_ino; i++) 898 if (inum == wbuf->inodes[i]) { 899 ret = 1; 900 break; 901 } 902 spin_unlock(&wbuf->lock); 903 904 return ret; 905 } 906 907 /** 908 * ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode. 909 * @c: UBIFS file-system description object 910 * @inode: inode to synchronize 911 * 912 * This function synchronizes write-buffers which contain nodes belonging to 913 * @inode. Returns zero in case of success and a negative error code in case of 914 * failure. 915 */ 916 int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode) 917 { 918 int i, err = 0; 919 920 for (i = 0; i < c->jhead_cnt; i++) { 921 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf; 922 923 if (i == GCHD) 924 /* 925 * GC head is special, do not look at it. Even if the 926 * head contains something related to this inode, it is 927 * a _copy_ of corresponding on-flash node which sits 928 * somewhere else. 929 */ 930 continue; 931 932 if (!wbuf_has_ino(wbuf, inode->i_ino)) 933 continue; 934 935 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); 936 if (wbuf_has_ino(wbuf, inode->i_ino)) 937 err = ubifs_wbuf_sync_nolock(wbuf); 938 mutex_unlock(&wbuf->io_mutex); 939 940 if (err) { 941 ubifs_ro_mode(c, err); 942 return err; 943 } 944 } 945 return 0; 946 } 947