1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This file is part of UBIFS.
   4 *
   5 * Copyright (C) 2006-2008 Nokia Corporation.
   6 * Copyright (C) 2006, 2007 University of Szeged, Hungary
   7 *
   8 * Authors: Artem Bityutskiy (Битюцкий Артём)
   9 *          Adrian Hunter
  10 *          Zoltan Sogor
  11 */
  12
  13/*
  14 * This file implements UBIFS I/O subsystem which provides various I/O-related
  15 * helper functions (reading/writing/checking/validating nodes) and implements
  16 * write-buffering support. Write buffers help to save space which otherwise
  17 * 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 the
  19 * buffer is full or when it is not used for some time (by timer). This is
  20 * similar to the mechanism is used by JFFS2.
  21 *
  22 * UBIFS distinguishes between minimum write size (@c->min_io_size) and maximum
  23 * write size (@c->max_write_size). The latter is the maximum amount of bytes
  24 * the underlying flash is able to program at a time, and writing in
  25 * @c->max_write_size units should presumably be faster. Obviously,
  26 * @c->min_io_size <= @c->max_write_size. Write-buffers are of
  27 * @c->max_write_size bytes in size for maximum performance. However, when a
  28 * write-buffer is flushed, only the portion of it (aligned to @c->min_io_size
  29 * 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 one
  33 * hand, we want to write in optimal @c->max_write_size bytes chunks, which
  34 * also means aligning writes at the @c->max_write_size bytes offsets. On the
  35 * other hand, we do not want to waste space when synchronizing the write
  36 * buffer, so during synchronization we writes in smaller chunks. And this makes
  37 * the next write offset to be not aligned to @c->max_write_size bytes. So the
  38 * have to make sure that the write-buffer offset (@wbuf->offs) becomes aligned
  39 * to @c->max_write_size bytes again. We do this by temporarily shrinking
  40 * write-buffer size (@wbuf->size).
  41 *
  42 * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by
  43 * mutexes defined inside these objects. Since sometimes upper-level code
  44 * has to lock the write-buffer (e.g. journal space reservation code), many
  45 * functions related to write-buffers have "nolock" suffix which means that the
  46 * 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 not
  49 * aligned, UBIFS starts the next node from the aligned address, and the padded
  50 * bytes may contain any rubbish. In other words, UBIFS does not put padding
  51 * 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 it
  55 * 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 when
  58 * 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 object
  68 * @err: error code which is the reason of switching to R/O mode
  69 */
  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 some
  83 * additional checks and UBIFS debugging stuff. See corresponding UBI function
  84 * 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 the
  95	 * @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	else
 116		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	else
 136		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	else
 156		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	else
 175		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 object
 218 * @buf: node to check
 219 * @len: node length
 220 * @lnum: logical eraseblock number
 221 * @offs: offset within the logical eraseblock
 222 * @quiet: print no messages
 223 * @must_chk_crc: indicates whether to always check the CRC
 224 *
 225 * This function checks node magic number and CRC checksum. This function also
 226 * validates node length to prevent UBIFS from becoming crazy when an attacker
 227 * feeds it a file-system image with incorrect nodes. For example, too large
 228 * node length in the common header could cause UBIFS to read memory outside of
 229 * allocated buffer when checking the CRC checksum.
 230 *
 231 * This function may skip data nodes CRC checking if @c->no_chk_data_crc is
 232 * true, which is controlled by corresponding UBIFS mount option. However, if
 233 * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
 234 * checked. Similarly, if @c->mounting or @c->remounting_rw is true (we are
 235 * mounting or re-mounting to R/W mode), @c->no_chk_data_crc is ignored and CRC
 236 * is checked. This is because during mounting or re-mounting from R/O mode to
 237 * R/W mode we may read journal nodes (when replying the journal or doing the
 238 * recovery) and the journal nodes may potentially be corrupted, so checking is
 239 * required.
 240 *
 241 * This function returns zero in case of success and %-EUCLEAN in case of bad
 242 * 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 object
 315 * @buf: buffer to put padding to
 316 * @pad: how many bytes to pad
 317 *
 318 * The flash media obliges us to write only in chunks of %c->min_io_size and
 319 * when we have to write less data we add padding node to the write-buffer and
 320 * pad it to the next minimal I/O unit's boundary. Padding nodes help when the
 321 * media is being scanned. If the amount of wasted space is not enough to fit a
 322 * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes
 323 * pattern (%UBIFS_PADDING_BYTE).
 324 *
 325 * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is
 326 * 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 object
 357 */
 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 object
 410 * @node: the node to pad
 411 * @len: node length
 412 * @hmac_offs: offset of the HMAC in the node
 413 * @pad: if the buffer has to be padded
 414 *
 415 * This function prepares node at @node to be written to the media - it
 416 * calculates node CRC, fills the common header, and adds proper padding up to
 417 * the next minimum I/O unit if @pad is not zero. if @hmac_offs is positive then
 418 * 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 object
 443 * @node: the node to pad
 444 * @len: node length
 445 * @pad: if the buffer has to be padded
 446 *
 447 * This function prepares node at @node to be written to the media - it
 448 * calculates node CRC, fills the common header, and adds proper padding up to
 449 * 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 fail
 455	 * 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 object
 463 * @node: the node to pad
 464 * @len: node length
 465 * @last: indicates the last node of the group
 466 *
 467 * This function prepares node at @node to be written to the media - it
 468 * 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	else
 483		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 object
 510 * @wbuf: write-buffer descriptor
 511 */
 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 descriptor
 536 */
 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 synchronize
 548 *
 549 * This function synchronizes write-buffer @buf and returns zero in case of
 550 * success or a negative error code in case of failure.
 551 *
 552 * Note, although write-buffers are of @c->max_write_size, this function does
 553 * 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 part
 555 * 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 necessary
 584	 * 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 in
 599	 * @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, make
 601	 * sure that @wbuf->offs + @wbuf->size is aligned to
 602	 * @c->max_write_size. This way we make sure that after next
 603	 * write-buffer flush we are again at the optimal offset (aligned to
 604	 * @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	else
 611		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-buffer
 626 * @lnum: logical eraseblock number to seek to
 627 * @offs: logical eraseblock offset to seek to
 628 *
 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 a
 631 * 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	else
 652		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 object
 663 *
 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 of
 666 * 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, so
 690		 * 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-buffer
 727 * @buf: node to write
 728 * @len: node length
 729 *
 730 * This function writes data to flash via write-buffer @wbuf. This means that
 731 * the last piece of the node won't reach the flash media immediately if it
 732 * does not take whole max. write unit (@c->max_write_size). Instead, the node
 733 * will sit in RAM until the write-buffer is synchronized (e.g., by timer, or
 734 * because more data are appended to the write-buffer).
 735 *
 736 * This function returns zero in case of success and a negative error code in
 737 * case of failure. If the node cannot be written because there is no more
 738 * 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 within
 774		 * 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			else
 795				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 within
 813		 * current available space. We have to fill and flush
 814		 * 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 to
 831		 * @c->max_write_size and @wbuf->size is less than
 832		 * @c->max_write_size. Write @wbuf->size bytes to make sure the
 833		 * following writes are done in optimal @c->max_write_size
 834		 * 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 the
 851	 * 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 wbuf
 853	 * 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' because
 877		 * parameter 'len' is not 8 bytes aligned, so here we read
 878		 * 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 whole
 900		 * max. write unit, so write it to the write-buffer and we are
 901		 * 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	else
 913		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 object
 945 * @buf: the node to write
 946 * @len: node length
 947 * @lnum: logical eraseblock number
 948 * @offs: offset within the logical eraseblock
 949 * @hmac_offs: offset of the HMAC within the node
 950 *
 951 * This function automatically fills node magic number, assigns sequence
 952 * number, and calculates node CRC checksum. The length of the @buf buffer has
 953 * to be aligned to the minimal I/O unit size. This function automatically
 954 * appends padding node and padding bytes if needed. Returns zero in case of
 955 * 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 object
 987 * @buf: the node to write
 988 * @len: node length
 989 * @lnum: logical eraseblock number
 990 * @offs: offset within the logical eraseblock
 991 *
 992 * This function automatically fills node magic number, assigns sequence
 993 * number, and calculates node CRC checksum. The length of the @buf buffer has
 994 * to be aligned to the minimal I/O unit size. This function automatically
 995 * appends padding node and padding bytes if needed. Returns zero in case of
 996 * 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 data
1007 * @buf: buffer to read to
1008 * @type: node type
1009 * @len: node length
1010 * @lnum: logical eraseblock number
1011 * @offs: offset within the logical eraseblock
1012 *
1013 * This function reads a node of known type and length, checks it and stores
1014 * in @buf. If the node partially or fully sits in the write-buffer, this
1015 * 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 negative
1017 * 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 object
1086 * @buf: buffer to read to
1087 * @type: node type
1088 * @len: node length (not aligned)
1089 * @lnum: logical eraseblock number
1090 * @offs: offset within the logical eraseblock
1091 *
1092 * This function reads a node of known type and length, checks it and
1093 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
1094 * 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 object
1145 * @wbuf: write-buffer to initialize
1146 *
1147 * This function initializes write-buffer. Returns zero in case of success
1148 * %-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, then
1170	 * 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 add
1190 * @inum: the inode number
1191 *
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-buffer
1209 * @inum: the inode number
1210 *
1211 * This function returns with %1 if the write-buffer contains some data from the
1212 * 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 object
1232 * @inode: inode to synchronize
1233 *
1234 * This function synchronizes write-buffers which contain nodes belonging to
1235 * @inode. Returns zero in case of success and a negative error code in case of
1236 * 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 the
1248			 * head contains something related to this inode, it is
1249			 * a _copy_ of corresponding on-flash node which sits
1250			 * 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}