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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * This file is part of UBIFS.4 *5 * Copyright (C) 2006-2008 Nokia Corporation.6 * Copyright (C) 2006, 2007 University of Szeged, Hungary7 *8 * Authors: Artem Bityutskiy (Битюцкий Артём)9 * Adrian Hunter10 * Zoltan Sogor11 */12 13/*14 * This file implements UBIFS I/O subsystem which provides various I/O-related15 * helper functions (reading/writing/checking/validating nodes) and implements16 * write-buffering support. Write buffers help to save space which otherwise17 * would have been wasted for padding to the nearest minimal I/O unit boundary.18 * Instead, data first goes to the write-buffer and is flushed when the19 * buffer is full or when it is not used for some time (by timer). This is20 * similar to the mechanism is used by JFFS2.21 *22 * UBIFS distinguishes between minimum write size (@c->min_io_size) and maximum23 * write size (@c->max_write_size). The latter is the maximum amount of bytes24 * the underlying flash is able to program at a time, and writing in25 * @c->max_write_size units should presumably be faster. Obviously,26 * @c->min_io_size <= @c->max_write_size. Write-buffers are of27 * @c->max_write_size bytes in size for maximum performance. However, when a28 * write-buffer is flushed, only the portion of it (aligned to @c->min_io_size29 * boundary) which contains data is written, not the whole write-buffer,30 * because this is more space-efficient.31 *32 * This optimization adds few complications to the code. Indeed, on the one33 * hand, we want to write in optimal @c->max_write_size bytes chunks, which34 * also means aligning writes at the @c->max_write_size bytes offsets. On the35 * other hand, we do not want to waste space when synchronizing the write36 * buffer, so during synchronization we writes in smaller chunks. And this makes37 * the next write offset to be not aligned to @c->max_write_size bytes. So the38 * have to make sure that the write-buffer offset (@wbuf->offs) becomes aligned39 * to @c->max_write_size bytes again. We do this by temporarily shrinking40 * write-buffer size (@wbuf->size).41 *42 * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by43 * mutexes defined inside these objects. Since sometimes upper-level code44 * has to lock the write-buffer (e.g. journal space reservation code), many45 * functions related to write-buffers have "nolock" suffix which means that the46 * caller has to lock the write-buffer before calling this function.47 *48 * UBIFS stores nodes at 64 bit-aligned addresses. If the node length is not49 * aligned, UBIFS starts the next node from the aligned address, and the padded50 * bytes may contain any rubbish. In other words, UBIFS does not put padding51 * bytes in those small gaps. Common headers of nodes store real node lengths,52 * not aligned lengths. Indexing nodes also store real lengths in branches.53 *54 * UBIFS uses padding when it pads to the next min. I/O unit. In this case it55 * uses padding nodes or padding bytes, if the padding node does not fit.56 *57 * All UBIFS nodes are protected by CRC checksums and UBIFS checks CRC when58 * they are read from the flash media.59 */60 61#include <linux/crc32.h>62#include <linux/slab.h>63#include "ubifs.h"64 65/**66 * ubifs_ro_mode - switch UBIFS to read read-only mode.67 * @c: UBIFS file-system description object68 * @err: error code which is the reason of switching to R/O mode69 */70void ubifs_ro_mode(struct ubifs_info *c, int err)71{72 if (!c->ro_error) {73 c->ro_error = 1;74 c->no_chk_data_crc = 0;75 c->vfs_sb->s_flags |= SB_RDONLY;76 ubifs_warn(c, "switched to read-only mode, error %d", err);77 dump_stack();78 }79}80 81/*82 * Below are simple wrappers over UBI I/O functions which include some83 * additional checks and UBIFS debugging stuff. See corresponding UBI function84 * for more information.85 */86 87int ubifs_leb_read(const struct ubifs_info *c, int lnum, void *buf, int offs,88 int len, int even_ebadmsg)89{90 int err;91 92 err = ubi_read(c->ubi, lnum, buf, offs, len);93 /*94 * In case of %-EBADMSG print the error message only if the95 * @even_ebadmsg is true.96 */97 if (err && (err != -EBADMSG || even_ebadmsg)) {98 ubifs_err(c, "reading %d bytes from LEB %d:%d failed, error %d",99 len, lnum, offs, err);100 dump_stack();101 }102 return err;103}104 105int ubifs_leb_write(struct ubifs_info *c, int lnum, const void *buf, int offs,106 int len)107{108 int err;109 110 ubifs_assert(c, !c->ro_media && !c->ro_mount);111 if (c->ro_error)112 return -EROFS;113 if (!dbg_is_tst_rcvry(c))114 err = ubi_leb_write(c->ubi, lnum, buf, offs, len);115 else116 err = dbg_leb_write(c, lnum, buf, offs, len);117 if (err) {118 ubifs_err(c, "writing %d bytes to LEB %d:%d failed, error %d",119 len, lnum, offs, err);120 ubifs_ro_mode(c, err);121 dump_stack();122 }123 return err;124}125 126int ubifs_leb_change(struct ubifs_info *c, int lnum, const void *buf, int len)127{128 int err;129 130 ubifs_assert(c, !c->ro_media && !c->ro_mount);131 if (c->ro_error)132 return -EROFS;133 if (!dbg_is_tst_rcvry(c))134 err = ubi_leb_change(c->ubi, lnum, buf, len);135 else136 err = dbg_leb_change(c, lnum, buf, len);137 if (err) {138 ubifs_err(c, "changing %d bytes in LEB %d failed, error %d",139 len, lnum, err);140 ubifs_ro_mode(c, err);141 dump_stack();142 }143 return err;144}145 146int ubifs_leb_unmap(struct ubifs_info *c, int lnum)147{148 int err;149 150 ubifs_assert(c, !c->ro_media && !c->ro_mount);151 if (c->ro_error)152 return -EROFS;153 if (!dbg_is_tst_rcvry(c))154 err = ubi_leb_unmap(c->ubi, lnum);155 else156 err = dbg_leb_unmap(c, lnum);157 if (err) {158 ubifs_err(c, "unmap LEB %d failed, error %d", lnum, err);159 ubifs_ro_mode(c, err);160 dump_stack();161 }162 return err;163}164 165int ubifs_leb_map(struct ubifs_info *c, int lnum)166{167 int err;168 169 ubifs_assert(c, !c->ro_media && !c->ro_mount);170 if (c->ro_error)171 return -EROFS;172 if (!dbg_is_tst_rcvry(c))173 err = ubi_leb_map(c->ubi, lnum);174 else175 err = dbg_leb_map(c, lnum);176 if (err) {177 ubifs_err(c, "mapping LEB %d failed, error %d", lnum, err);178 ubifs_ro_mode(c, err);179 dump_stack();180 }181 return err;182}183 184int ubifs_is_mapped(const struct ubifs_info *c, int lnum)185{186 int err;187 188 err = ubi_is_mapped(c->ubi, lnum);189 if (err < 0) {190 ubifs_err(c, "ubi_is_mapped failed for LEB %d, error %d",191 lnum, err);192 dump_stack();193 }194 return err;195}196 197static void record_magic_error(struct ubifs_stats_info *stats)198{199 if (stats)200 stats->magic_errors++;201}202 203static void record_node_error(struct ubifs_stats_info *stats)204{205 if (stats)206 stats->node_errors++;207}208 209static void record_crc_error(struct ubifs_stats_info *stats)210{211 if (stats)212 stats->crc_errors++;213}214 215/**216 * ubifs_check_node - check node.217 * @c: UBIFS file-system description object218 * @buf: node to check219 * @len: node length220 * @lnum: logical eraseblock number221 * @offs: offset within the logical eraseblock222 * @quiet: print no messages223 * @must_chk_crc: indicates whether to always check the CRC224 *225 * This function checks node magic number and CRC checksum. This function also226 * validates node length to prevent UBIFS from becoming crazy when an attacker227 * feeds it a file-system image with incorrect nodes. For example, too large228 * node length in the common header could cause UBIFS to read memory outside of229 * allocated buffer when checking the CRC checksum.230 *231 * This function may skip data nodes CRC checking if @c->no_chk_data_crc is232 * true, which is controlled by corresponding UBIFS mount option. However, if233 * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is234 * checked. Similarly, if @c->mounting or @c->remounting_rw is true (we are235 * mounting or re-mounting to R/W mode), @c->no_chk_data_crc is ignored and CRC236 * is checked. This is because during mounting or re-mounting from R/O mode to237 * R/W mode we may read journal nodes (when replying the journal or doing the238 * recovery) and the journal nodes may potentially be corrupted, so checking is239 * required.240 *241 * This function returns zero in case of success and %-EUCLEAN in case of bad242 * CRC or magic.243 */244int ubifs_check_node(const struct ubifs_info *c, const void *buf, int len,245 int lnum, int offs, int quiet, int must_chk_crc)246{247 int err = -EINVAL, type, node_len;248 uint32_t crc, node_crc, magic;249 const struct ubifs_ch *ch = buf;250 251 ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);252 ubifs_assert(c, !(offs & 7) && offs < c->leb_size);253 254 magic = le32_to_cpu(ch->magic);255 if (magic != UBIFS_NODE_MAGIC) {256 if (!quiet)257 ubifs_err(c, "bad magic %#08x, expected %#08x",258 magic, UBIFS_NODE_MAGIC);259 record_magic_error(c->stats);260 err = -EUCLEAN;261 goto out;262 }263 264 type = ch->node_type;265 if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {266 if (!quiet)267 ubifs_err(c, "bad node type %d", type);268 record_node_error(c->stats);269 goto out;270 }271 272 node_len = le32_to_cpu(ch->len);273 if (node_len + offs > c->leb_size)274 goto out_len;275 276 if (c->ranges[type].max_len == 0) {277 if (node_len != c->ranges[type].len)278 goto out_len;279 } else if (node_len < c->ranges[type].min_len ||280 node_len > c->ranges[type].max_len)281 goto out_len;282 283 if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->mounting &&284 !c->remounting_rw && c->no_chk_data_crc)285 return 0;286 287 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);288 node_crc = le32_to_cpu(ch->crc);289 if (crc != node_crc) {290 if (!quiet)291 ubifs_err(c, "bad CRC: calculated %#08x, read %#08x",292 crc, node_crc);293 record_crc_error(c->stats);294 err = -EUCLEAN;295 goto out;296 }297 298 return 0;299 300out_len:301 if (!quiet)302 ubifs_err(c, "bad node length %d", node_len);303out:304 if (!quiet) {305 ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);306 ubifs_dump_node(c, buf, len);307 dump_stack();308 }309 return err;310}311 312/**313 * ubifs_pad - pad flash space.314 * @c: UBIFS file-system description object315 * @buf: buffer to put padding to316 * @pad: how many bytes to pad317 *318 * The flash media obliges us to write only in chunks of %c->min_io_size and319 * when we have to write less data we add padding node to the write-buffer and320 * pad it to the next minimal I/O unit's boundary. Padding nodes help when the321 * media is being scanned. If the amount of wasted space is not enough to fit a322 * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes323 * pattern (%UBIFS_PADDING_BYTE).324 *325 * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is326 * used.327 */328void ubifs_pad(const struct ubifs_info *c, void *buf, int pad)329{330 uint32_t crc;331 332 ubifs_assert(c, pad >= 0);333 334 if (pad >= UBIFS_PAD_NODE_SZ) {335 struct ubifs_ch *ch = buf;336 struct ubifs_pad_node *pad_node = buf;337 338 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);339 ch->node_type = UBIFS_PAD_NODE;340 ch->group_type = UBIFS_NO_NODE_GROUP;341 ch->padding[0] = ch->padding[1] = 0;342 ch->sqnum = 0;343 ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ);344 pad -= UBIFS_PAD_NODE_SZ;345 pad_node->pad_len = cpu_to_le32(pad);346 crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8);347 ch->crc = cpu_to_le32(crc);348 memset(buf + UBIFS_PAD_NODE_SZ, 0, pad);349 } else if (pad > 0)350 /* Too little space, padding node won't fit */351 memset(buf, UBIFS_PADDING_BYTE, pad);352}353 354/**355 * next_sqnum - get next sequence number.356 * @c: UBIFS file-system description object357 */358static unsigned long long next_sqnum(struct ubifs_info *c)359{360 unsigned long long sqnum;361 362 spin_lock(&c->cnt_lock);363 sqnum = ++c->max_sqnum;364 spin_unlock(&c->cnt_lock);365 366 if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) {367 if (sqnum >= SQNUM_WATERMARK) {368 ubifs_err(c, "sequence number overflow %llu, end of life",369 sqnum);370 ubifs_ro_mode(c, -EINVAL);371 }372 ubifs_warn(c, "running out of sequence numbers, end of life soon");373 }374 375 return sqnum;376}377 378void ubifs_init_node(struct ubifs_info *c, void *node, int len, int pad)379{380 struct ubifs_ch *ch = node;381 unsigned long long sqnum = next_sqnum(c);382 383 ubifs_assert(c, len >= UBIFS_CH_SZ);384 385 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);386 ch->len = cpu_to_le32(len);387 ch->group_type = UBIFS_NO_NODE_GROUP;388 ch->sqnum = cpu_to_le64(sqnum);389 ch->padding[0] = ch->padding[1] = 0;390 391 if (pad) {392 len = ALIGN(len, 8);393 pad = ALIGN(len, c->min_io_size) - len;394 ubifs_pad(c, node + len, pad);395 }396}397 398void ubifs_crc_node(struct ubifs_info *c, void *node, int len)399{400 struct ubifs_ch *ch = node;401 uint32_t crc;402 403 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);404 ch->crc = cpu_to_le32(crc);405}406 407/**408 * ubifs_prepare_node_hmac - prepare node to be written to flash.409 * @c: UBIFS file-system description object410 * @node: the node to pad411 * @len: node length412 * @hmac_offs: offset of the HMAC in the node413 * @pad: if the buffer has to be padded414 *415 * This function prepares node at @node to be written to the media - it416 * calculates node CRC, fills the common header, and adds proper padding up to417 * the next minimum I/O unit if @pad is not zero. if @hmac_offs is positive then418 * a HMAC is inserted into the node at the given offset.419 *420 * This function returns 0 for success or a negative error code otherwise.421 */422int ubifs_prepare_node_hmac(struct ubifs_info *c, void *node, int len,423 int hmac_offs, int pad)424{425 int err;426 427 ubifs_init_node(c, node, len, pad);428 429 if (hmac_offs > 0) {430 err = ubifs_node_insert_hmac(c, node, len, hmac_offs);431 if (err)432 return err;433 }434 435 ubifs_crc_node(c, node, len);436 437 return 0;438}439 440/**441 * ubifs_prepare_node - prepare node to be written to flash.442 * @c: UBIFS file-system description object443 * @node: the node to pad444 * @len: node length445 * @pad: if the buffer has to be padded446 *447 * This function prepares node at @node to be written to the media - it448 * calculates node CRC, fills the common header, and adds proper padding up to449 * the next minimum I/O unit if @pad is not zero.450 */451void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)452{453 /*454 * Deliberately ignore return value since this function can only fail455 * when a hmac offset is given.456 */457 ubifs_prepare_node_hmac(c, node, len, 0, pad);458}459 460/**461 * ubifs_prep_grp_node - prepare node of a group to be written to flash.462 * @c: UBIFS file-system description object463 * @node: the node to pad464 * @len: node length465 * @last: indicates the last node of the group466 *467 * This function prepares node at @node to be written to the media - it468 * calculates node CRC and fills the common header.469 */470void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last)471{472 uint32_t crc;473 struct ubifs_ch *ch = node;474 unsigned long long sqnum = next_sqnum(c);475 476 ubifs_assert(c, len >= UBIFS_CH_SZ);477 478 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);479 ch->len = cpu_to_le32(len);480 if (last)481 ch->group_type = UBIFS_LAST_OF_NODE_GROUP;482 else483 ch->group_type = UBIFS_IN_NODE_GROUP;484 ch->sqnum = cpu_to_le64(sqnum);485 ch->padding[0] = ch->padding[1] = 0;486 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);487 ch->crc = cpu_to_le32(crc);488}489 490/**491 * wbuf_timer_callback_nolock - write-buffer timer callback function.492 * @timer: timer data (write-buffer descriptor)493 *494 * This function is called when the write-buffer timer expires.495 */496static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer)497{498 struct ubifs_wbuf *wbuf = container_of(timer, struct ubifs_wbuf, timer);499 500 dbg_io("jhead %s", dbg_jhead(wbuf->jhead));501 wbuf->need_sync = 1;502 wbuf->c->need_wbuf_sync = 1;503 ubifs_wake_up_bgt(wbuf->c);504 return HRTIMER_NORESTART;505}506 507/**508 * new_wbuf_timer_nolock - start new write-buffer timer.509 * @c: UBIFS file-system description object510 * @wbuf: write-buffer descriptor511 */512static void new_wbuf_timer_nolock(struct ubifs_info *c, struct ubifs_wbuf *wbuf)513{514 ktime_t softlimit = ms_to_ktime(dirty_writeback_interval * 10);515 unsigned long long delta = dirty_writeback_interval;516 517 /* centi to milli, milli to nano, then 10% */518 delta *= 10ULL * NSEC_PER_MSEC / 10ULL;519 520 ubifs_assert(c, !hrtimer_active(&wbuf->timer));521 ubifs_assert(c, delta <= ULONG_MAX);522 523 if (wbuf->no_timer)524 return;525 dbg_io("set timer for jhead %s, %llu-%llu millisecs",526 dbg_jhead(wbuf->jhead),527 div_u64(ktime_to_ns(softlimit), USEC_PER_SEC),528 div_u64(ktime_to_ns(softlimit) + delta, USEC_PER_SEC));529 hrtimer_start_range_ns(&wbuf->timer, softlimit, delta,530 HRTIMER_MODE_REL);531}532 533/**534 * cancel_wbuf_timer_nolock - cancel write-buffer timer.535 * @wbuf: write-buffer descriptor536 */537static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)538{539 if (wbuf->no_timer)540 return;541 wbuf->need_sync = 0;542 hrtimer_cancel(&wbuf->timer);543}544 545/**546 * ubifs_wbuf_sync_nolock - synchronize write-buffer.547 * @wbuf: write-buffer to synchronize548 *549 * This function synchronizes write-buffer @buf and returns zero in case of550 * success or a negative error code in case of failure.551 *552 * Note, although write-buffers are of @c->max_write_size, this function does553 * not necessarily writes all @c->max_write_size bytes to the flash. Instead,554 * if the write-buffer is only partially filled with data, only the used part555 * of the write-buffer (aligned on @c->min_io_size boundary) is synchronized.556 * This way we waste less space.557 */558int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)559{560 struct ubifs_info *c = wbuf->c;561 int err, dirt, sync_len;562 563 cancel_wbuf_timer_nolock(wbuf);564 if (!wbuf->used || wbuf->lnum == -1)565 /* Write-buffer is empty or not seeked */566 return 0;567 568 dbg_io("LEB %d:%d, %d bytes, jhead %s",569 wbuf->lnum, wbuf->offs, wbuf->used, dbg_jhead(wbuf->jhead));570 ubifs_assert(c, !(wbuf->avail & 7));571 ubifs_assert(c, wbuf->offs + wbuf->size <= c->leb_size);572 ubifs_assert(c, wbuf->size >= c->min_io_size);573 ubifs_assert(c, wbuf->size <= c->max_write_size);574 ubifs_assert(c, wbuf->size % c->min_io_size == 0);575 ubifs_assert(c, !c->ro_media && !c->ro_mount);576 if (c->leb_size - wbuf->offs >= c->max_write_size)577 ubifs_assert(c, !((wbuf->offs + wbuf->size) % c->max_write_size));578 579 if (c->ro_error)580 return -EROFS;581 582 /*583 * Do not write whole write buffer but write only the minimum necessary584 * amount of min. I/O units.585 */586 sync_len = ALIGN(wbuf->used, c->min_io_size);587 dirt = sync_len - wbuf->used;588 if (dirt)589 ubifs_pad(c, wbuf->buf + wbuf->used, dirt);590 err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, sync_len);591 if (err)592 return err;593 594 spin_lock(&wbuf->lock);595 wbuf->offs += sync_len;596 /*597 * Now @wbuf->offs is not necessarily aligned to @c->max_write_size.598 * But our goal is to optimize writes and make sure we write in599 * @c->max_write_size chunks and to @c->max_write_size-aligned offset.600 * Thus, if @wbuf->offs is not aligned to @c->max_write_size now, make601 * sure that @wbuf->offs + @wbuf->size is aligned to602 * @c->max_write_size. This way we make sure that after next603 * write-buffer flush we are again at the optimal offset (aligned to604 * @c->max_write_size).605 */606 if (c->leb_size - wbuf->offs < c->max_write_size)607 wbuf->size = c->leb_size - wbuf->offs;608 else if (wbuf->offs & (c->max_write_size - 1))609 wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs;610 else611 wbuf->size = c->max_write_size;612 wbuf->avail = wbuf->size;613 wbuf->used = 0;614 wbuf->next_ino = 0;615 spin_unlock(&wbuf->lock);616 617 if (wbuf->sync_callback)618 err = wbuf->sync_callback(c, wbuf->lnum,619 c->leb_size - wbuf->offs, dirt);620 return err;621}622 623/**624 * ubifs_wbuf_seek_nolock - seek write-buffer.625 * @wbuf: write-buffer626 * @lnum: logical eraseblock number to seek to627 * @offs: logical eraseblock offset to seek to628 *629 * This function targets the write-buffer to logical eraseblock @lnum:@offs.630 * The write-buffer has to be empty. Returns zero in case of success and a631 * negative error code in case of failure.632 */633int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs)634{635 const struct ubifs_info *c = wbuf->c;636 637 dbg_io("LEB %d:%d, jhead %s", lnum, offs, dbg_jhead(wbuf->jhead));638 ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt);639 ubifs_assert(c, offs >= 0 && offs <= c->leb_size);640 ubifs_assert(c, offs % c->min_io_size == 0 && !(offs & 7));641 ubifs_assert(c, lnum != wbuf->lnum);642 ubifs_assert(c, wbuf->used == 0);643 644 spin_lock(&wbuf->lock);645 wbuf->lnum = lnum;646 wbuf->offs = offs;647 if (c->leb_size - wbuf->offs < c->max_write_size)648 wbuf->size = c->leb_size - wbuf->offs;649 else if (wbuf->offs & (c->max_write_size - 1))650 wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs;651 else652 wbuf->size = c->max_write_size;653 wbuf->avail = wbuf->size;654 wbuf->used = 0;655 spin_unlock(&wbuf->lock);656 657 return 0;658}659 660/**661 * ubifs_bg_wbufs_sync - synchronize write-buffers.662 * @c: UBIFS file-system description object663 *664 * This function is called by background thread to synchronize write-buffers.665 * Returns zero in case of success and a negative error code in case of666 * failure.667 */668int ubifs_bg_wbufs_sync(struct ubifs_info *c)669{670 int err, i;671 672 ubifs_assert(c, !c->ro_media && !c->ro_mount);673 if (!c->need_wbuf_sync)674 return 0;675 c->need_wbuf_sync = 0;676 677 if (c->ro_error) {678 err = -EROFS;679 goto out_timers;680 }681 682 dbg_io("synchronize");683 for (i = 0; i < c->jhead_cnt; i++) {684 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;685 686 cond_resched();687 688 /*689 * If the mutex is locked then wbuf is being changed, so690 * synchronization is not necessary.691 */692 if (mutex_is_locked(&wbuf->io_mutex))693 continue;694 695 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);696 if (!wbuf->need_sync) {697 mutex_unlock(&wbuf->io_mutex);698 continue;699 }700 701 err = ubifs_wbuf_sync_nolock(wbuf);702 mutex_unlock(&wbuf->io_mutex);703 if (err) {704 ubifs_err(c, "cannot sync write-buffer, error %d", err);705 ubifs_ro_mode(c, err);706 goto out_timers;707 }708 }709 710 return 0;711 712out_timers:713 /* Cancel all timers to prevent repeated errors */714 for (i = 0; i < c->jhead_cnt; i++) {715 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;716 717 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);718 cancel_wbuf_timer_nolock(wbuf);719 mutex_unlock(&wbuf->io_mutex);720 }721 return err;722}723 724/**725 * ubifs_wbuf_write_nolock - write data to flash via write-buffer.726 * @wbuf: write-buffer727 * @buf: node to write728 * @len: node length729 *730 * This function writes data to flash via write-buffer @wbuf. This means that731 * the last piece of the node won't reach the flash media immediately if it732 * does not take whole max. write unit (@c->max_write_size). Instead, the node733 * will sit in RAM until the write-buffer is synchronized (e.g., by timer, or734 * because more data are appended to the write-buffer).735 *736 * This function returns zero in case of success and a negative error code in737 * case of failure. If the node cannot be written because there is no more738 * space in this logical eraseblock, %-ENOSPC is returned.739 */740int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)741{742 struct ubifs_info *c = wbuf->c;743 int err, n, written = 0, aligned_len = ALIGN(len, 8);744 745 dbg_io("%d bytes (%s) to jhead %s wbuf at LEB %d:%d", len,746 dbg_ntype(((struct ubifs_ch *)buf)->node_type),747 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs + wbuf->used);748 ubifs_assert(c, len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);749 ubifs_assert(c, wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);750 ubifs_assert(c, !(wbuf->offs & 7) && wbuf->offs <= c->leb_size);751 ubifs_assert(c, wbuf->avail > 0 && wbuf->avail <= wbuf->size);752 ubifs_assert(c, wbuf->size >= c->min_io_size);753 ubifs_assert(c, wbuf->size <= c->max_write_size);754 ubifs_assert(c, wbuf->size % c->min_io_size == 0);755 ubifs_assert(c, mutex_is_locked(&wbuf->io_mutex));756 ubifs_assert(c, !c->ro_media && !c->ro_mount);757 ubifs_assert(c, !c->space_fixup);758 if (c->leb_size - wbuf->offs >= c->max_write_size)759 ubifs_assert(c, !((wbuf->offs + wbuf->size) % c->max_write_size));760 761 if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {762 err = -ENOSPC;763 goto out;764 }765 766 cancel_wbuf_timer_nolock(wbuf);767 768 if (c->ro_error)769 return -EROFS;770 771 if (aligned_len <= wbuf->avail) {772 /*773 * The node is not very large and fits entirely within774 * write-buffer.775 */776 memcpy(wbuf->buf + wbuf->used, buf, len);777 if (aligned_len > len) {778 ubifs_assert(c, aligned_len - len < 8);779 ubifs_pad(c, wbuf->buf + wbuf->used + len, aligned_len - len);780 }781 782 if (aligned_len == wbuf->avail) {783 dbg_io("flush jhead %s wbuf to LEB %d:%d",784 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);785 err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf,786 wbuf->offs, wbuf->size);787 if (err)788 goto out;789 790 spin_lock(&wbuf->lock);791 wbuf->offs += wbuf->size;792 if (c->leb_size - wbuf->offs >= c->max_write_size)793 wbuf->size = c->max_write_size;794 else795 wbuf->size = c->leb_size - wbuf->offs;796 wbuf->avail = wbuf->size;797 wbuf->used = 0;798 wbuf->next_ino = 0;799 spin_unlock(&wbuf->lock);800 } else {801 spin_lock(&wbuf->lock);802 wbuf->avail -= aligned_len;803 wbuf->used += aligned_len;804 spin_unlock(&wbuf->lock);805 }806 807 goto exit;808 }809 810 if (wbuf->used) {811 /*812 * The node is large enough and does not fit entirely within813 * current available space. We have to fill and flush814 * write-buffer and switch to the next max. write unit.815 */816 dbg_io("flush jhead %s wbuf to LEB %d:%d",817 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);818 memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);819 err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs,820 wbuf->size);821 if (err)822 goto out;823 824 wbuf->offs += wbuf->size;825 len -= wbuf->avail;826 aligned_len -= wbuf->avail;827 written += wbuf->avail;828 } else if (wbuf->offs & (c->max_write_size - 1)) {829 /*830 * The write-buffer offset is not aligned to831 * @c->max_write_size and @wbuf->size is less than832 * @c->max_write_size. Write @wbuf->size bytes to make sure the833 * following writes are done in optimal @c->max_write_size834 * chunks.835 */836 dbg_io("write %d bytes to LEB %d:%d",837 wbuf->size, wbuf->lnum, wbuf->offs);838 err = ubifs_leb_write(c, wbuf->lnum, buf, wbuf->offs,839 wbuf->size);840 if (err)841 goto out;842 843 wbuf->offs += wbuf->size;844 len -= wbuf->size;845 aligned_len -= wbuf->size;846 written += wbuf->size;847 }848 849 /*850 * The remaining data may take more whole max. write units, so write the851 * remains multiple to max. write unit size directly to the flash media.852 * We align node length to 8-byte boundary because we anyway flash wbuf853 * if the remaining space is less than 8 bytes.854 */855 n = aligned_len >> c->max_write_shift;856 if (n) {857 int m = n - 1;858 859 dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum,860 wbuf->offs);861 862 if (m) {863 /* '(n-1)<<c->max_write_shift < len' is always true. */864 m <<= c->max_write_shift;865 err = ubifs_leb_write(c, wbuf->lnum, buf + written,866 wbuf->offs, m);867 if (err)868 goto out;869 wbuf->offs += m;870 aligned_len -= m;871 len -= m;872 written += m;873 }874 875 /*876 * The non-written len of buf may be less than 'n' because877 * parameter 'len' is not 8 bytes aligned, so here we read878 * min(len, n) bytes from buf.879 */880 n = 1 << c->max_write_shift;881 memcpy(wbuf->buf, buf + written, min(len, n));882 if (n > len) {883 ubifs_assert(c, n - len < 8);884 ubifs_pad(c, wbuf->buf + len, n - len);885 }886 887 err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, n);888 if (err)889 goto out;890 wbuf->offs += n;891 aligned_len -= n;892 len -= min(len, n);893 written += n;894 }895 896 spin_lock(&wbuf->lock);897 if (aligned_len) {898 /*899 * And now we have what's left and what does not take whole900 * max. write unit, so write it to the write-buffer and we are901 * done.902 */903 memcpy(wbuf->buf, buf + written, len);904 if (aligned_len > len) {905 ubifs_assert(c, aligned_len - len < 8);906 ubifs_pad(c, wbuf->buf + len, aligned_len - len);907 }908 }909 910 if (c->leb_size - wbuf->offs >= c->max_write_size)911 wbuf->size = c->max_write_size;912 else913 wbuf->size = c->leb_size - wbuf->offs;914 wbuf->avail = wbuf->size - aligned_len;915 wbuf->used = aligned_len;916 wbuf->next_ino = 0;917 spin_unlock(&wbuf->lock);918 919exit:920 if (wbuf->sync_callback) {921 int free = c->leb_size - wbuf->offs - wbuf->used;922 923 err = wbuf->sync_callback(c, wbuf->lnum, free, 0);924 if (err)925 goto out;926 }927 928 if (wbuf->used)929 new_wbuf_timer_nolock(c, wbuf);930 931 return 0;932 933out:934 ubifs_err(c, "cannot write %d bytes to LEB %d:%d, error %d",935 len, wbuf->lnum, wbuf->offs, err);936 ubifs_dump_node(c, buf, written + len);937 dump_stack();938 ubifs_dump_leb(c, wbuf->lnum);939 return err;940}941 942/**943 * ubifs_write_node_hmac - write node to the media.944 * @c: UBIFS file-system description object945 * @buf: the node to write946 * @len: node length947 * @lnum: logical eraseblock number948 * @offs: offset within the logical eraseblock949 * @hmac_offs: offset of the HMAC within the node950 *951 * This function automatically fills node magic number, assigns sequence952 * number, and calculates node CRC checksum. The length of the @buf buffer has953 * to be aligned to the minimal I/O unit size. This function automatically954 * appends padding node and padding bytes if needed. Returns zero in case of955 * success and a negative error code in case of failure.956 */957int ubifs_write_node_hmac(struct ubifs_info *c, void *buf, int len, int lnum,958 int offs, int hmac_offs)959{960 int err, buf_len = ALIGN(len, c->min_io_size);961 962 dbg_io("LEB %d:%d, %s, length %d (aligned %d)",963 lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,964 buf_len);965 ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);966 ubifs_assert(c, offs % c->min_io_size == 0 && offs < c->leb_size);967 ubifs_assert(c, !c->ro_media && !c->ro_mount);968 ubifs_assert(c, !c->space_fixup);969 970 if (c->ro_error)971 return -EROFS;972 973 err = ubifs_prepare_node_hmac(c, buf, len, hmac_offs, 1);974 if (err)975 return err;976 977 err = ubifs_leb_write(c, lnum, buf, offs, buf_len);978 if (err)979 ubifs_dump_node(c, buf, len);980 981 return err;982}983 984/**985 * ubifs_write_node - write node to the media.986 * @c: UBIFS file-system description object987 * @buf: the node to write988 * @len: node length989 * @lnum: logical eraseblock number990 * @offs: offset within the logical eraseblock991 *992 * This function automatically fills node magic number, assigns sequence993 * number, and calculates node CRC checksum. The length of the @buf buffer has994 * to be aligned to the minimal I/O unit size. This function automatically995 * appends padding node and padding bytes if needed. Returns zero in case of996 * success and a negative error code in case of failure.997 */998int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,999 int offs)1000{1001 return ubifs_write_node_hmac(c, buf, len, lnum, offs, -1);1002}1003 1004/**1005 * ubifs_read_node_wbuf - read node from the media or write-buffer.1006 * @wbuf: wbuf to check for un-written data1007 * @buf: buffer to read to1008 * @type: node type1009 * @len: node length1010 * @lnum: logical eraseblock number1011 * @offs: offset within the logical eraseblock1012 *1013 * This function reads a node of known type and length, checks it and stores1014 * in @buf. If the node partially or fully sits in the write-buffer, this1015 * function takes data from the buffer, otherwise it reads the flash media.1016 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative1017 * error code in case of failure.1018 */1019int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,1020 int lnum, int offs)1021{1022 const struct ubifs_info *c = wbuf->c;1023 int err, rlen, overlap;1024 struct ubifs_ch *ch = buf;1025 1026 dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs,1027 dbg_ntype(type), len, dbg_jhead(wbuf->jhead));1028 ubifs_assert(c, wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);1029 ubifs_assert(c, !(offs & 7) && offs < c->leb_size);1030 ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT);1031 1032 spin_lock(&wbuf->lock);1033 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);1034 if (!overlap) {1035 /* We may safely unlock the write-buffer and read the data */1036 spin_unlock(&wbuf->lock);1037 return ubifs_read_node(c, buf, type, len, lnum, offs);1038 }1039 1040 /* Don't read under wbuf */1041 rlen = wbuf->offs - offs;1042 if (rlen < 0)1043 rlen = 0;1044 1045 /* Copy the rest from the write-buffer */1046 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);1047 spin_unlock(&wbuf->lock);1048 1049 if (rlen > 0) {1050 /* Read everything that goes before write-buffer */1051 err = ubifs_leb_read(c, lnum, buf, offs, rlen, 0);1052 if (err && err != -EBADMSG)1053 return err;1054 }1055 1056 if (type != ch->node_type) {1057 ubifs_err(c, "bad node type (%d but expected %d)",1058 ch->node_type, type);1059 goto out;1060 }1061 1062 err = ubifs_check_node(c, buf, len, lnum, offs, 0, 0);1063 if (err) {1064 ubifs_err(c, "expected node type %d", type);1065 return err;1066 }1067 1068 rlen = le32_to_cpu(ch->len);1069 if (rlen != len) {1070 ubifs_err(c, "bad node length %d, expected %d", rlen, len);1071 goto out;1072 }1073 1074 return 0;1075 1076out:1077 ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);1078 ubifs_dump_node(c, buf, len);1079 dump_stack();1080 return -EINVAL;1081}1082 1083/**1084 * ubifs_read_node - read node.1085 * @c: UBIFS file-system description object1086 * @buf: buffer to read to1087 * @type: node type1088 * @len: node length (not aligned)1089 * @lnum: logical eraseblock number1090 * @offs: offset within the logical eraseblock1091 *1092 * This function reads a node of known type and length, checks it and1093 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched1094 * and a negative error code in case of failure.1095 */1096int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,1097 int lnum, int offs)1098{1099 int err, l;1100 struct ubifs_ch *ch = buf;1101 1102 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);1103 ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);1104 ubifs_assert(c, len >= UBIFS_CH_SZ && offs + len <= c->leb_size);1105 ubifs_assert(c, !(offs & 7) && offs < c->leb_size);1106 ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT);1107 1108 err = ubifs_leb_read(c, lnum, buf, offs, len, 0);1109 if (err && err != -EBADMSG)1110 return err;1111 1112 if (type != ch->node_type) {1113 ubifs_errc(c, "bad node type (%d but expected %d)",1114 ch->node_type, type);1115 goto out;1116 }1117 1118 err = ubifs_check_node(c, buf, len, lnum, offs, 0, 0);1119 if (err) {1120 ubifs_errc(c, "expected node type %d", type);1121 return err;1122 }1123 1124 l = le32_to_cpu(ch->len);1125 if (l != len) {1126 ubifs_errc(c, "bad node length %d, expected %d", l, len);1127 goto out;1128 }1129 1130 return 0;1131 1132out:1133 ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum,1134 offs, ubi_is_mapped(c->ubi, lnum));1135 if (!c->probing) {1136 ubifs_dump_node(c, buf, len);1137 dump_stack();1138 }1139 return -EINVAL;1140}1141 1142/**1143 * ubifs_wbuf_init - initialize write-buffer.1144 * @c: UBIFS file-system description object1145 * @wbuf: write-buffer to initialize1146 *1147 * This function initializes write-buffer. Returns zero in case of success1148 * %-ENOMEM in case of failure.1149 */1150int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf)1151{1152 size_t size;1153 1154 wbuf->buf = kmalloc(c->max_write_size, GFP_KERNEL);1155 if (!wbuf->buf)1156 return -ENOMEM;1157 1158 size = (c->max_write_size / UBIFS_CH_SZ + 1) * sizeof(ino_t);1159 wbuf->inodes = kmalloc(size, GFP_KERNEL);1160 if (!wbuf->inodes) {1161 kfree(wbuf->buf);1162 wbuf->buf = NULL;1163 return -ENOMEM;1164 }1165 1166 wbuf->used = 0;1167 wbuf->lnum = wbuf->offs = -1;1168 /*1169 * If the LEB starts at the max. write size aligned address, then1170 * write-buffer size has to be set to @c->max_write_size. Otherwise,1171 * set it to something smaller so that it ends at the closest max.1172 * write size boundary.1173 */1174 size = c->max_write_size - (c->leb_start % c->max_write_size);1175 wbuf->avail = wbuf->size = size;1176 wbuf->sync_callback = NULL;1177 mutex_init(&wbuf->io_mutex);1178 spin_lock_init(&wbuf->lock);1179 wbuf->c = c;1180 wbuf->next_ino = 0;1181 1182 hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);1183 wbuf->timer.function = wbuf_timer_callback_nolock;1184 return 0;1185}1186 1187/**1188 * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array.1189 * @wbuf: the write-buffer where to add1190 * @inum: the inode number1191 *1192 * This function adds an inode number to the inode array of the write-buffer.1193 */1194void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum)1195{1196 if (!wbuf->buf)1197 /* NOR flash or something similar */1198 return;1199 1200 spin_lock(&wbuf->lock);1201 if (wbuf->used)1202 wbuf->inodes[wbuf->next_ino++] = inum;1203 spin_unlock(&wbuf->lock);1204}1205 1206/**1207 * wbuf_has_ino - returns if the wbuf contains data from the inode.1208 * @wbuf: the write-buffer1209 * @inum: the inode number1210 *1211 * This function returns with %1 if the write-buffer contains some data from the1212 * given inode otherwise it returns with %0.1213 */1214static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum)1215{1216 int i, ret = 0;1217 1218 spin_lock(&wbuf->lock);1219 for (i = 0; i < wbuf->next_ino; i++)1220 if (inum == wbuf->inodes[i]) {1221 ret = 1;1222 break;1223 }1224 spin_unlock(&wbuf->lock);1225 1226 return ret;1227}1228 1229/**1230 * ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode.1231 * @c: UBIFS file-system description object1232 * @inode: inode to synchronize1233 *1234 * This function synchronizes write-buffers which contain nodes belonging to1235 * @inode. Returns zero in case of success and a negative error code in case of1236 * failure.1237 */1238int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)1239{1240 int i, err = 0;1241 1242 for (i = 0; i < c->jhead_cnt; i++) {1243 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;1244 1245 if (i == GCHD)1246 /*1247 * GC head is special, do not look at it. Even if the1248 * head contains something related to this inode, it is1249 * a _copy_ of corresponding on-flash node which sits1250 * somewhere else.1251 */1252 continue;1253 1254 if (!wbuf_has_ino(wbuf, inode->i_ino))1255 continue;1256 1257 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);1258 if (wbuf_has_ino(wbuf, inode->i_ino))1259 err = ubifs_wbuf_sync_nolock(wbuf);1260 mutex_unlock(&wbuf->io_mutex);1261 1262 if (err) {1263 ubifs_ro_mode(c, err);1264 return err;1265 }1266 }1267 return 0;1268}1269