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
 197/**
 198 * ubifs_check_node - check node.
 199 * @c: UBIFS file-system description object
 200 * @buf: node to check
 201 * @lnum: logical eraseblock number
 202 * @offs: offset within the logical eraseblock
 203 * @quiet: print no messages
 204 * @must_chk_crc: indicates whether to always check the CRC
 205 *
 206 * This function checks node magic number and CRC checksum. This function also
 207 * validates node length to prevent UBIFS from becoming crazy when an attacker
 208 * feeds it a file-system image with incorrect nodes. For example, too large
 209 * node length in the common header could cause UBIFS to read memory outside of
 210 * allocated buffer when checking the CRC checksum.
 211 *
 212 * This function may skip data nodes CRC checking if @c->no_chk_data_crc is
 213 * true, which is controlled by corresponding UBIFS mount option. However, if
 214 * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
 215 * checked. Similarly, if @c->mounting or @c->remounting_rw is true (we are
 216 * mounting or re-mounting to R/W mode), @c->no_chk_data_crc is ignored and CRC
 217 * is checked. This is because during mounting or re-mounting from R/O mode to
 218 * R/W mode we may read journal nodes (when replying the journal or doing the
 219 * recovery) and the journal nodes may potentially be corrupted, so checking is
 220 * required.
 221 *
 222 * This function returns zero in case of success and %-EUCLEAN in case of bad
 223 * CRC or magic.
 224 */
 225int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
 226		     int offs, int quiet, int must_chk_crc)
 227{
 228	int err = -EINVAL, type, node_len;
 229	uint32_t crc, node_crc, magic;
 230	const struct ubifs_ch *ch = buf;
 231
 232	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
 233	ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
 234
 235	magic = le32_to_cpu(ch->magic);
 236	if (magic != UBIFS_NODE_MAGIC) {
 237		if (!quiet)
 238			ubifs_err(c, "bad magic %#08x, expected %#08x",
 239				  magic, UBIFS_NODE_MAGIC);
 240		err = -EUCLEAN;
 241		goto out;
 242	}
 243
 244	type = ch->node_type;
 245	if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
 246		if (!quiet)
 247			ubifs_err(c, "bad node type %d", type);
 248		goto out;
 249	}
 250
 251	node_len = le32_to_cpu(ch->len);
 252	if (node_len + offs > c->leb_size)
 253		goto out_len;
 254
 255	if (c->ranges[type].max_len == 0) {
 256		if (node_len != c->ranges[type].len)
 257			goto out_len;
 258	} else if (node_len < c->ranges[type].min_len ||
 259		   node_len > c->ranges[type].max_len)
 260		goto out_len;
 261
 262	if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->mounting &&
 263	    !c->remounting_rw && c->no_chk_data_crc)
 264		return 0;
 265
 266	crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
 267	node_crc = le32_to_cpu(ch->crc);
 268	if (crc != node_crc) {
 269		if (!quiet)
 270			ubifs_err(c, "bad CRC: calculated %#08x, read %#08x",
 271				  crc, node_crc);
 272		err = -EUCLEAN;
 273		goto out;
 274	}
 275
 276	return 0;
 277
 278out_len:
 279	if (!quiet)
 280		ubifs_err(c, "bad node length %d", node_len);
 
 
 281out:
 282	if (!quiet) {
 283		ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);
 284		ubifs_dump_node(c, buf);
 
 
 
 
 
 
 
 
 
 
 285		dump_stack();
 286	}
 287	return err;
 288}
 289
 290/**
 291 * ubifs_pad - pad flash space.
 292 * @c: UBIFS file-system description object
 293 * @buf: buffer to put padding to
 294 * @pad: how many bytes to pad
 295 *
 296 * The flash media obliges us to write only in chunks of %c->min_io_size and
 297 * when we have to write less data we add padding node to the write-buffer and
 298 * pad it to the next minimal I/O unit's boundary. Padding nodes help when the
 299 * media is being scanned. If the amount of wasted space is not enough to fit a
 300 * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes
 301 * pattern (%UBIFS_PADDING_BYTE).
 302 *
 303 * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is
 304 * used.
 305 */
 306void ubifs_pad(const struct ubifs_info *c, void *buf, int pad)
 307{
 308	uint32_t crc;
 309
 310	ubifs_assert(c, pad >= 0 && !(pad & 7));
 311
 312	if (pad >= UBIFS_PAD_NODE_SZ) {
 313		struct ubifs_ch *ch = buf;
 314		struct ubifs_pad_node *pad_node = buf;
 315
 316		ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
 317		ch->node_type = UBIFS_PAD_NODE;
 318		ch->group_type = UBIFS_NO_NODE_GROUP;
 319		ch->padding[0] = ch->padding[1] = 0;
 320		ch->sqnum = 0;
 321		ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ);
 322		pad -= UBIFS_PAD_NODE_SZ;
 323		pad_node->pad_len = cpu_to_le32(pad);
 324		crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8);
 325		ch->crc = cpu_to_le32(crc);
 326		memset(buf + UBIFS_PAD_NODE_SZ, 0, pad);
 327	} else if (pad > 0)
 328		/* Too little space, padding node won't fit */
 329		memset(buf, UBIFS_PADDING_BYTE, pad);
 330}
 331
 332/**
 333 * next_sqnum - get next sequence number.
 334 * @c: UBIFS file-system description object
 335 */
 336static unsigned long long next_sqnum(struct ubifs_info *c)
 337{
 338	unsigned long long sqnum;
 339
 340	spin_lock(&c->cnt_lock);
 341	sqnum = ++c->max_sqnum;
 342	spin_unlock(&c->cnt_lock);
 343
 344	if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) {
 345		if (sqnum >= SQNUM_WATERMARK) {
 346			ubifs_err(c, "sequence number overflow %llu, end of life",
 347				  sqnum);
 348			ubifs_ro_mode(c, -EINVAL);
 349		}
 350		ubifs_warn(c, "running out of sequence numbers, end of life soon");
 351	}
 352
 353	return sqnum;
 354}
 355
 356void ubifs_init_node(struct ubifs_info *c, void *node, int len, int pad)
 357{
 358	struct ubifs_ch *ch = node;
 359	unsigned long long sqnum = next_sqnum(c);
 360
 361	ubifs_assert(c, len >= UBIFS_CH_SZ);
 362
 363	ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
 364	ch->len = cpu_to_le32(len);
 365	ch->group_type = UBIFS_NO_NODE_GROUP;
 366	ch->sqnum = cpu_to_le64(sqnum);
 367	ch->padding[0] = ch->padding[1] = 0;
 368
 369	if (pad) {
 370		len = ALIGN(len, 8);
 371		pad = ALIGN(len, c->min_io_size) - len;
 372		ubifs_pad(c, node + len, pad);
 373	}
 374}
 375
 376void ubifs_crc_node(struct ubifs_info *c, void *node, int len)
 377{
 378	struct ubifs_ch *ch = node;
 379	uint32_t crc;
 380
 381	crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
 382	ch->crc = cpu_to_le32(crc);
 383}
 384
 385/**
 386 * ubifs_prepare_node_hmac - prepare node to be written to flash.
 387 * @c: UBIFS file-system description object
 388 * @node: the node to pad
 389 * @len: node length
 390 * @hmac_offs: offset of the HMAC in the node
 391 * @pad: if the buffer has to be padded
 392 *
 393 * This function prepares node at @node to be written to the media - it
 394 * calculates node CRC, fills the common header, and adds proper padding up to
 395 * the next minimum I/O unit if @pad is not zero. if @hmac_offs is positive then
 396 * a HMAC is inserted into the node at the given offset.
 397 *
 398 * This function returns 0 for success or a negative error code otherwise.
 399 */
 400int ubifs_prepare_node_hmac(struct ubifs_info *c, void *node, int len,
 401			    int hmac_offs, int pad)
 402{
 403	int err;
 404
 405	ubifs_init_node(c, node, len, pad);
 406
 407	if (hmac_offs > 0) {
 408		err = ubifs_node_insert_hmac(c, node, len, hmac_offs);
 409		if (err)
 410			return err;
 411	}
 412
 413	ubifs_crc_node(c, node, len);
 414
 415	return 0;
 416}
 417
 418/**
 419 * ubifs_prepare_node - prepare node to be written to flash.
 420 * @c: UBIFS file-system description object
 421 * @node: the node to pad
 422 * @len: node length
 423 * @pad: if the buffer has to be padded
 424 *
 425 * This function prepares node at @node to be written to the media - it
 426 * calculates node CRC, fills the common header, and adds proper padding up to
 427 * the next minimum I/O unit if @pad is not zero.
 428 */
 429void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
 430{
 431	/*
 432	 * Deliberately ignore return value since this function can only fail
 433	 * when a hmac offset is given.
 434	 */
 435	ubifs_prepare_node_hmac(c, node, len, 0, pad);
 436}
 437
 438/**
 439 * ubifs_prep_grp_node - prepare node of a group to be written to flash.
 440 * @c: UBIFS file-system description object
 441 * @node: the node to pad
 442 * @len: node length
 443 * @last: indicates the last node of the group
 444 *
 445 * This function prepares node at @node to be written to the media - it
 446 * calculates node CRC and fills the common header.
 447 */
 448void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last)
 449{
 450	uint32_t crc;
 451	struct ubifs_ch *ch = node;
 452	unsigned long long sqnum = next_sqnum(c);
 453
 454	ubifs_assert(c, len >= UBIFS_CH_SZ);
 455
 456	ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
 457	ch->len = cpu_to_le32(len);
 458	if (last)
 459		ch->group_type = UBIFS_LAST_OF_NODE_GROUP;
 460	else
 461		ch->group_type = UBIFS_IN_NODE_GROUP;
 462	ch->sqnum = cpu_to_le64(sqnum);
 463	ch->padding[0] = ch->padding[1] = 0;
 464	crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
 465	ch->crc = cpu_to_le32(crc);
 466}
 467
 468/**
 469 * wbuf_timer_callback - write-buffer timer callback function.
 470 * @timer: timer data (write-buffer descriptor)
 471 *
 472 * This function is called when the write-buffer timer expires.
 473 */
 474static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer)
 475{
 476	struct ubifs_wbuf *wbuf = container_of(timer, struct ubifs_wbuf, timer);
 477
 478	dbg_io("jhead %s", dbg_jhead(wbuf->jhead));
 479	wbuf->need_sync = 1;
 480	wbuf->c->need_wbuf_sync = 1;
 481	ubifs_wake_up_bgt(wbuf->c);
 482	return HRTIMER_NORESTART;
 483}
 484
 485/**
 486 * new_wbuf_timer - start new write-buffer timer.
 487 * @c: UBIFS file-system description object
 488 * @wbuf: write-buffer descriptor
 489 */
 490static void new_wbuf_timer_nolock(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
 491{
 492	ktime_t softlimit = ms_to_ktime(dirty_writeback_interval * 10);
 493	unsigned long long delta = dirty_writeback_interval;
 494
 495	/* centi to milli, milli to nano, then 10% */
 496	delta *= 10ULL * NSEC_PER_MSEC / 10ULL;
 497
 498	ubifs_assert(c, !hrtimer_active(&wbuf->timer));
 499	ubifs_assert(c, delta <= ULONG_MAX);
 500
 501	if (wbuf->no_timer)
 502		return;
 503	dbg_io("set timer for jhead %s, %llu-%llu millisecs",
 504	       dbg_jhead(wbuf->jhead),
 505	       div_u64(ktime_to_ns(softlimit), USEC_PER_SEC),
 506	       div_u64(ktime_to_ns(softlimit) + delta, USEC_PER_SEC));
 507	hrtimer_start_range_ns(&wbuf->timer, softlimit, delta,
 508			       HRTIMER_MODE_REL);
 509}
 510
 511/**
 512 * cancel_wbuf_timer - cancel write-buffer timer.
 513 * @wbuf: write-buffer descriptor
 514 */
 515static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
 516{
 517	if (wbuf->no_timer)
 518		return;
 519	wbuf->need_sync = 0;
 520	hrtimer_cancel(&wbuf->timer);
 521}
 522
 523/**
 524 * ubifs_wbuf_sync_nolock - synchronize write-buffer.
 525 * @wbuf: write-buffer to synchronize
 526 *
 527 * This function synchronizes write-buffer @buf and returns zero in case of
 528 * success or a negative error code in case of failure.
 529 *
 530 * Note, although write-buffers are of @c->max_write_size, this function does
 531 * not necessarily writes all @c->max_write_size bytes to the flash. Instead,
 532 * if the write-buffer is only partially filled with data, only the used part
 533 * of the write-buffer (aligned on @c->min_io_size boundary) is synchronized.
 534 * This way we waste less space.
 535 */
 536int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)
 537{
 538	struct ubifs_info *c = wbuf->c;
 539	int err, dirt, sync_len;
 540
 541	cancel_wbuf_timer_nolock(wbuf);
 542	if (!wbuf->used || wbuf->lnum == -1)
 543		/* Write-buffer is empty or not seeked */
 544		return 0;
 545
 546	dbg_io("LEB %d:%d, %d bytes, jhead %s",
 547	       wbuf->lnum, wbuf->offs, wbuf->used, dbg_jhead(wbuf->jhead));
 548	ubifs_assert(c, !(wbuf->avail & 7));
 549	ubifs_assert(c, wbuf->offs + wbuf->size <= c->leb_size);
 550	ubifs_assert(c, wbuf->size >= c->min_io_size);
 551	ubifs_assert(c, wbuf->size <= c->max_write_size);
 552	ubifs_assert(c, wbuf->size % c->min_io_size == 0);
 553	ubifs_assert(c, !c->ro_media && !c->ro_mount);
 554	if (c->leb_size - wbuf->offs >= c->max_write_size)
 555		ubifs_assert(c, !((wbuf->offs + wbuf->size) % c->max_write_size));
 556
 557	if (c->ro_error)
 558		return -EROFS;
 559
 560	/*
 561	 * Do not write whole write buffer but write only the minimum necessary
 562	 * amount of min. I/O units.
 563	 */
 564	sync_len = ALIGN(wbuf->used, c->min_io_size);
 565	dirt = sync_len - wbuf->used;
 566	if (dirt)
 567		ubifs_pad(c, wbuf->buf + wbuf->used, dirt);
 568	err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, sync_len);
 569	if (err)
 570		return err;
 571
 572	spin_lock(&wbuf->lock);
 573	wbuf->offs += sync_len;
 574	/*
 575	 * Now @wbuf->offs is not necessarily aligned to @c->max_write_size.
 576	 * But our goal is to optimize writes and make sure we write in
 577	 * @c->max_write_size chunks and to @c->max_write_size-aligned offset.
 578	 * Thus, if @wbuf->offs is not aligned to @c->max_write_size now, make
 579	 * sure that @wbuf->offs + @wbuf->size is aligned to
 580	 * @c->max_write_size. This way we make sure that after next
 581	 * write-buffer flush we are again at the optimal offset (aligned to
 582	 * @c->max_write_size).
 583	 */
 584	if (c->leb_size - wbuf->offs < c->max_write_size)
 585		wbuf->size = c->leb_size - wbuf->offs;
 586	else if (wbuf->offs & (c->max_write_size - 1))
 587		wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs;
 588	else
 589		wbuf->size = c->max_write_size;
 590	wbuf->avail = wbuf->size;
 591	wbuf->used = 0;
 592	wbuf->next_ino = 0;
 593	spin_unlock(&wbuf->lock);
 594
 595	if (wbuf->sync_callback)
 596		err = wbuf->sync_callback(c, wbuf->lnum,
 597					  c->leb_size - wbuf->offs, dirt);
 598	return err;
 599}
 600
 601/**
 602 * ubifs_wbuf_seek_nolock - seek write-buffer.
 603 * @wbuf: write-buffer
 604 * @lnum: logical eraseblock number to seek to
 605 * @offs: logical eraseblock offset to seek to
 606 *
 607 * This function targets the write-buffer to logical eraseblock @lnum:@offs.
 608 * The write-buffer has to be empty. Returns zero in case of success and a
 609 * negative error code in case of failure.
 610 */
 611int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs)
 612{
 613	const struct ubifs_info *c = wbuf->c;
 614
 615	dbg_io("LEB %d:%d, jhead %s", lnum, offs, dbg_jhead(wbuf->jhead));
 616	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt);
 617	ubifs_assert(c, offs >= 0 && offs <= c->leb_size);
 618	ubifs_assert(c, offs % c->min_io_size == 0 && !(offs & 7));
 619	ubifs_assert(c, lnum != wbuf->lnum);
 620	ubifs_assert(c, wbuf->used == 0);
 621
 622	spin_lock(&wbuf->lock);
 623	wbuf->lnum = lnum;
 624	wbuf->offs = offs;
 625	if (c->leb_size - wbuf->offs < c->max_write_size)
 626		wbuf->size = c->leb_size - wbuf->offs;
 627	else if (wbuf->offs & (c->max_write_size - 1))
 628		wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs;
 629	else
 630		wbuf->size = c->max_write_size;
 631	wbuf->avail = wbuf->size;
 632	wbuf->used = 0;
 633	spin_unlock(&wbuf->lock);
 634
 635	return 0;
 636}
 637
 638/**
 639 * ubifs_bg_wbufs_sync - synchronize write-buffers.
 640 * @c: UBIFS file-system description object
 641 *
 642 * This function is called by background thread to synchronize write-buffers.
 643 * Returns zero in case of success and a negative error code in case of
 644 * failure.
 645 */
 646int ubifs_bg_wbufs_sync(struct ubifs_info *c)
 647{
 648	int err, i;
 649
 650	ubifs_assert(c, !c->ro_media && !c->ro_mount);
 651	if (!c->need_wbuf_sync)
 652		return 0;
 653	c->need_wbuf_sync = 0;
 654
 655	if (c->ro_error) {
 656		err = -EROFS;
 657		goto out_timers;
 658	}
 659
 660	dbg_io("synchronize");
 661	for (i = 0; i < c->jhead_cnt; i++) {
 662		struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
 663
 664		cond_resched();
 665
 666		/*
 667		 * If the mutex is locked then wbuf is being changed, so
 668		 * synchronization is not necessary.
 669		 */
 670		if (mutex_is_locked(&wbuf->io_mutex))
 671			continue;
 672
 673		mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
 674		if (!wbuf->need_sync) {
 675			mutex_unlock(&wbuf->io_mutex);
 676			continue;
 677		}
 678
 679		err = ubifs_wbuf_sync_nolock(wbuf);
 680		mutex_unlock(&wbuf->io_mutex);
 681		if (err) {
 682			ubifs_err(c, "cannot sync write-buffer, error %d", err);
 683			ubifs_ro_mode(c, err);
 684			goto out_timers;
 685		}
 686	}
 687
 688	return 0;
 689
 690out_timers:
 691	/* Cancel all timers to prevent repeated errors */
 692	for (i = 0; i < c->jhead_cnt; i++) {
 693		struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
 694
 695		mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
 696		cancel_wbuf_timer_nolock(wbuf);
 697		mutex_unlock(&wbuf->io_mutex);
 698	}
 699	return err;
 700}
 701
 702/**
 703 * ubifs_wbuf_write_nolock - write data to flash via write-buffer.
 704 * @wbuf: write-buffer
 705 * @buf: node to write
 706 * @len: node length
 707 *
 708 * This function writes data to flash via write-buffer @wbuf. This means that
 709 * the last piece of the node won't reach the flash media immediately if it
 710 * does not take whole max. write unit (@c->max_write_size). Instead, the node
 711 * will sit in RAM until the write-buffer is synchronized (e.g., by timer, or
 712 * because more data are appended to the write-buffer).
 713 *
 714 * This function returns zero in case of success and a negative error code in
 715 * case of failure. If the node cannot be written because there is no more
 716 * space in this logical eraseblock, %-ENOSPC is returned.
 717 */
 718int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
 719{
 720	struct ubifs_info *c = wbuf->c;
 721	int err, written, n, aligned_len = ALIGN(len, 8);
 722
 723	dbg_io("%d bytes (%s) to jhead %s wbuf at LEB %d:%d", len,
 724	       dbg_ntype(((struct ubifs_ch *)buf)->node_type),
 725	       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs + wbuf->used);
 726	ubifs_assert(c, len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);
 727	ubifs_assert(c, wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);
 728	ubifs_assert(c, !(wbuf->offs & 7) && wbuf->offs <= c->leb_size);
 729	ubifs_assert(c, wbuf->avail > 0 && wbuf->avail <= wbuf->size);
 730	ubifs_assert(c, wbuf->size >= c->min_io_size);
 731	ubifs_assert(c, wbuf->size <= c->max_write_size);
 732	ubifs_assert(c, wbuf->size % c->min_io_size == 0);
 733	ubifs_assert(c, mutex_is_locked(&wbuf->io_mutex));
 734	ubifs_assert(c, !c->ro_media && !c->ro_mount);
 735	ubifs_assert(c, !c->space_fixup);
 736	if (c->leb_size - wbuf->offs >= c->max_write_size)
 737		ubifs_assert(c, !((wbuf->offs + wbuf->size) % c->max_write_size));
 738
 739	if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {
 740		err = -ENOSPC;
 741		goto out;
 742	}
 743
 744	cancel_wbuf_timer_nolock(wbuf);
 745
 746	if (c->ro_error)
 747		return -EROFS;
 748
 749	if (aligned_len <= wbuf->avail) {
 750		/*
 751		 * The node is not very large and fits entirely within
 752		 * write-buffer.
 753		 */
 754		memcpy(wbuf->buf + wbuf->used, buf, len);
 755
 756		if (aligned_len == wbuf->avail) {
 757			dbg_io("flush jhead %s wbuf to LEB %d:%d",
 758			       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
 759			err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf,
 760					      wbuf->offs, wbuf->size);
 761			if (err)
 762				goto out;
 763
 764			spin_lock(&wbuf->lock);
 765			wbuf->offs += wbuf->size;
 766			if (c->leb_size - wbuf->offs >= c->max_write_size)
 767				wbuf->size = c->max_write_size;
 768			else
 769				wbuf->size = c->leb_size - wbuf->offs;
 770			wbuf->avail = wbuf->size;
 771			wbuf->used = 0;
 772			wbuf->next_ino = 0;
 773			spin_unlock(&wbuf->lock);
 774		} else {
 775			spin_lock(&wbuf->lock);
 776			wbuf->avail -= aligned_len;
 777			wbuf->used += aligned_len;
 778			spin_unlock(&wbuf->lock);
 779		}
 780
 781		goto exit;
 782	}
 783
 784	written = 0;
 785
 786	if (wbuf->used) {
 787		/*
 788		 * The node is large enough and does not fit entirely within
 789		 * current available space. We have to fill and flush
 790		 * write-buffer and switch to the next max. write unit.
 791		 */
 792		dbg_io("flush jhead %s wbuf to LEB %d:%d",
 793		       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
 794		memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);
 795		err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs,
 796				      wbuf->size);
 797		if (err)
 798			goto out;
 799
 800		wbuf->offs += wbuf->size;
 801		len -= wbuf->avail;
 802		aligned_len -= wbuf->avail;
 803		written += wbuf->avail;
 804	} else if (wbuf->offs & (c->max_write_size - 1)) {
 805		/*
 806		 * The write-buffer offset is not aligned to
 807		 * @c->max_write_size and @wbuf->size is less than
 808		 * @c->max_write_size. Write @wbuf->size bytes to make sure the
 809		 * following writes are done in optimal @c->max_write_size
 810		 * chunks.
 811		 */
 812		dbg_io("write %d bytes to LEB %d:%d",
 813		       wbuf->size, wbuf->lnum, wbuf->offs);
 814		err = ubifs_leb_write(c, wbuf->lnum, buf, wbuf->offs,
 815				      wbuf->size);
 816		if (err)
 817			goto out;
 818
 819		wbuf->offs += wbuf->size;
 820		len -= wbuf->size;
 821		aligned_len -= wbuf->size;
 822		written += wbuf->size;
 823	}
 824
 825	/*
 826	 * The remaining data may take more whole max. write units, so write the
 827	 * remains multiple to max. write unit size directly to the flash media.
 828	 * We align node length to 8-byte boundary because we anyway flash wbuf
 829	 * if the remaining space is less than 8 bytes.
 830	 */
 831	n = aligned_len >> c->max_write_shift;
 832	if (n) {
 833		n <<= c->max_write_shift;
 834		dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum,
 835		       wbuf->offs);
 836		err = ubifs_leb_write(c, wbuf->lnum, buf + written,
 837				      wbuf->offs, n);
 838		if (err)
 839			goto out;
 840		wbuf->offs += n;
 841		aligned_len -= n;
 842		len -= n;
 843		written += n;
 844	}
 845
 846	spin_lock(&wbuf->lock);
 847	if (aligned_len)
 848		/*
 849		 * And now we have what's left and what does not take whole
 850		 * max. write unit, so write it to the write-buffer and we are
 851		 * done.
 852		 */
 853		memcpy(wbuf->buf, buf + written, len);
 854
 855	if (c->leb_size - wbuf->offs >= c->max_write_size)
 856		wbuf->size = c->max_write_size;
 857	else
 858		wbuf->size = c->leb_size - wbuf->offs;
 859	wbuf->avail = wbuf->size - aligned_len;
 860	wbuf->used = aligned_len;
 861	wbuf->next_ino = 0;
 862	spin_unlock(&wbuf->lock);
 863
 864exit:
 865	if (wbuf->sync_callback) {
 866		int free = c->leb_size - wbuf->offs - wbuf->used;
 867
 868		err = wbuf->sync_callback(c, wbuf->lnum, free, 0);
 869		if (err)
 870			goto out;
 871	}
 872
 873	if (wbuf->used)
 874		new_wbuf_timer_nolock(c, wbuf);
 875
 876	return 0;
 877
 878out:
 879	ubifs_err(c, "cannot write %d bytes to LEB %d:%d, error %d",
 880		  len, wbuf->lnum, wbuf->offs, err);
 881	ubifs_dump_node(c, buf);
 882	dump_stack();
 883	ubifs_dump_leb(c, wbuf->lnum);
 884	return err;
 885}
 886
 887/**
 888 * ubifs_write_node_hmac - write node to the media.
 889 * @c: UBIFS file-system description object
 890 * @buf: the node to write
 891 * @len: node length
 892 * @lnum: logical eraseblock number
 893 * @offs: offset within the logical eraseblock
 894 * @hmac_offs: offset of the HMAC within the node
 895 *
 896 * This function automatically fills node magic number, assigns sequence
 897 * number, and calculates node CRC checksum. The length of the @buf buffer has
 898 * to be aligned to the minimal I/O unit size. This function automatically
 899 * appends padding node and padding bytes if needed. Returns zero in case of
 900 * success and a negative error code in case of failure.
 901 */
 902int ubifs_write_node_hmac(struct ubifs_info *c, void *buf, int len, int lnum,
 903			  int offs, int hmac_offs)
 904{
 905	int err, buf_len = ALIGN(len, c->min_io_size);
 906
 907	dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
 908	       lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
 909	       buf_len);
 910	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
 911	ubifs_assert(c, offs % c->min_io_size == 0 && offs < c->leb_size);
 912	ubifs_assert(c, !c->ro_media && !c->ro_mount);
 913	ubifs_assert(c, !c->space_fixup);
 914
 915	if (c->ro_error)
 916		return -EROFS;
 917
 918	err = ubifs_prepare_node_hmac(c, buf, len, hmac_offs, 1);
 919	if (err)
 920		return err;
 921
 922	err = ubifs_leb_write(c, lnum, buf, offs, buf_len);
 923	if (err)
 924		ubifs_dump_node(c, buf);
 925
 926	return err;
 927}
 928
 929/**
 930 * ubifs_write_node - write node to the media.
 931 * @c: UBIFS file-system description object
 932 * @buf: the node to write
 933 * @len: node length
 934 * @lnum: logical eraseblock number
 935 * @offs: offset within the logical eraseblock
 936 *
 937 * This function automatically fills node magic number, assigns sequence
 938 * number, and calculates node CRC checksum. The length of the @buf buffer has
 939 * to be aligned to the minimal I/O unit size. This function automatically
 940 * appends padding node and padding bytes if needed. Returns zero in case of
 941 * success and a negative error code in case of failure.
 942 */
 943int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
 944		     int offs)
 945{
 946	return ubifs_write_node_hmac(c, buf, len, lnum, offs, -1);
 947}
 948
 949/**
 950 * ubifs_read_node_wbuf - read node from the media or write-buffer.
 951 * @wbuf: wbuf to check for un-written data
 952 * @buf: buffer to read to
 953 * @type: node type
 954 * @len: node length
 955 * @lnum: logical eraseblock number
 956 * @offs: offset within the logical eraseblock
 957 *
 958 * This function reads a node of known type and length, checks it and stores
 959 * in @buf. If the node partially or fully sits in the write-buffer, this
 960 * function takes data from the buffer, otherwise it reads the flash media.
 961 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
 962 * error code in case of failure.
 963 */
 964int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
 965			 int lnum, int offs)
 966{
 967	const struct ubifs_info *c = wbuf->c;
 968	int err, rlen, overlap;
 969	struct ubifs_ch *ch = buf;
 970
 971	dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs,
 972	       dbg_ntype(type), len, dbg_jhead(wbuf->jhead));
 973	ubifs_assert(c, wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
 974	ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
 975	ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT);
 976
 977	spin_lock(&wbuf->lock);
 978	overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
 979	if (!overlap) {
 980		/* We may safely unlock the write-buffer and read the data */
 981		spin_unlock(&wbuf->lock);
 982		return ubifs_read_node(c, buf, type, len, lnum, offs);
 983	}
 984
 985	/* Don't read under wbuf */
 986	rlen = wbuf->offs - offs;
 987	if (rlen < 0)
 988		rlen = 0;
 989
 990	/* Copy the rest from the write-buffer */
 991	memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
 992	spin_unlock(&wbuf->lock);
 993
 994	if (rlen > 0) {
 995		/* Read everything that goes before write-buffer */
 996		err = ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
 997		if (err && err != -EBADMSG)
 998			return err;
 999	}
1000
1001	if (type != ch->node_type) {
1002		ubifs_err(c, "bad node type (%d but expected %d)",
1003			  ch->node_type, type);
1004		goto out;
1005	}
1006
1007	err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
1008	if (err) {
1009		ubifs_err(c, "expected node type %d", type);
1010		return err;
1011	}
1012
1013	rlen = le32_to_cpu(ch->len);
1014	if (rlen != len) {
1015		ubifs_err(c, "bad node length %d, expected %d", rlen, len);
1016		goto out;
1017	}
1018
1019	return 0;
1020
1021out:
1022	ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);
1023	ubifs_dump_node(c, buf);
1024	dump_stack();
1025	return -EINVAL;
1026}
1027
1028/**
1029 * ubifs_read_node - read node.
1030 * @c: UBIFS file-system description object
1031 * @buf: buffer to read to
1032 * @type: node type
1033 * @len: node length (not aligned)
1034 * @lnum: logical eraseblock number
1035 * @offs: offset within the logical eraseblock
1036 *
1037 * This function reads a node of known type and and length, checks it and
1038 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
1039 * and a negative error code in case of failure.
1040 */
1041int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
1042		    int lnum, int offs)
1043{
1044	int err, l;
1045	struct ubifs_ch *ch = buf;
1046
1047	dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
1048	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
1049	ubifs_assert(c, len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
1050	ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
1051	ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT);
1052
1053	err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
1054	if (err && err != -EBADMSG)
1055		return err;
1056
1057	if (type != ch->node_type) {
1058		ubifs_errc(c, "bad node type (%d but expected %d)",
1059			   ch->node_type, type);
1060		goto out;
1061	}
1062
1063	err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
1064	if (err) {
1065		ubifs_errc(c, "expected node type %d", type);
1066		return err;
1067	}
1068
1069	l = le32_to_cpu(ch->len);
1070	if (l != len) {
1071		ubifs_errc(c, "bad node length %d, expected %d", l, len);
1072		goto out;
1073	}
1074
1075	return 0;
1076
1077out:
1078	ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum,
1079		   offs, ubi_is_mapped(c->ubi, lnum));
1080	if (!c->probing) {
1081		ubifs_dump_node(c, buf);
1082		dump_stack();
1083	}
1084	return -EINVAL;
1085}
1086
1087/**
1088 * ubifs_wbuf_init - initialize write-buffer.
1089 * @c: UBIFS file-system description object
1090 * @wbuf: write-buffer to initialize
1091 *
1092 * This function initializes write-buffer. Returns zero in case of success
1093 * %-ENOMEM in case of failure.
1094 */
1095int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
1096{
1097	size_t size;
1098
1099	wbuf->buf = kmalloc(c->max_write_size, GFP_KERNEL);
1100	if (!wbuf->buf)
1101		return -ENOMEM;
1102
1103	size = (c->max_write_size / UBIFS_CH_SZ + 1) * sizeof(ino_t);
1104	wbuf->inodes = kmalloc(size, GFP_KERNEL);
1105	if (!wbuf->inodes) {
1106		kfree(wbuf->buf);
1107		wbuf->buf = NULL;
1108		return -ENOMEM;
1109	}
1110
1111	wbuf->used = 0;
1112	wbuf->lnum = wbuf->offs = -1;
1113	/*
1114	 * If the LEB starts at the max. write size aligned address, then
1115	 * write-buffer size has to be set to @c->max_write_size. Otherwise,
1116	 * set it to something smaller so that it ends at the closest max.
1117	 * write size boundary.
1118	 */
1119	size = c->max_write_size - (c->leb_start % c->max_write_size);
1120	wbuf->avail = wbuf->size = size;
1121	wbuf->sync_callback = NULL;
1122	mutex_init(&wbuf->io_mutex);
1123	spin_lock_init(&wbuf->lock);
1124	wbuf->c = c;
1125	wbuf->next_ino = 0;
1126
1127	hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1128	wbuf->timer.function = wbuf_timer_callback_nolock;
1129	return 0;
1130}
1131
1132/**
1133 * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array.
1134 * @wbuf: the write-buffer where to add
1135 * @inum: the inode number
1136 *
1137 * This function adds an inode number to the inode array of the write-buffer.
1138 */
1139void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum)
1140{
1141	if (!wbuf->buf)
1142		/* NOR flash or something similar */
1143		return;
1144
1145	spin_lock(&wbuf->lock);
1146	if (wbuf->used)
1147		wbuf->inodes[wbuf->next_ino++] = inum;
1148	spin_unlock(&wbuf->lock);
1149}
1150
1151/**
1152 * wbuf_has_ino - returns if the wbuf contains data from the inode.
1153 * @wbuf: the write-buffer
1154 * @inum: the inode number
1155 *
1156 * This function returns with %1 if the write-buffer contains some data from the
1157 * given inode otherwise it returns with %0.
1158 */
1159static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum)
1160{
1161	int i, ret = 0;
1162
1163	spin_lock(&wbuf->lock);
1164	for (i = 0; i < wbuf->next_ino; i++)
1165		if (inum == wbuf->inodes[i]) {
1166			ret = 1;
1167			break;
1168		}
1169	spin_unlock(&wbuf->lock);
1170
1171	return ret;
1172}
1173
1174/**
1175 * ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode.
1176 * @c: UBIFS file-system description object
1177 * @inode: inode to synchronize
1178 *
1179 * This function synchronizes write-buffers which contain nodes belonging to
1180 * @inode. Returns zero in case of success and a negative error code in case of
1181 * failure.
1182 */
1183int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)
1184{
1185	int i, err = 0;
1186
1187	for (i = 0; i < c->jhead_cnt; i++) {
1188		struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
1189
1190		if (i == GCHD)
1191			/*
1192			 * GC head is special, do not look at it. Even if the
1193			 * head contains something related to this inode, it is
1194			 * a _copy_ of corresponding on-flash node which sits
1195			 * somewhere else.
1196			 */
1197			continue;
1198
1199		if (!wbuf_has_ino(wbuf, inode->i_ino))
1200			continue;
1201
1202		mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
1203		if (wbuf_has_ino(wbuf, inode->i_ino))
1204			err = ubifs_wbuf_sync_nolock(wbuf);
1205		mutex_unlock(&wbuf->io_mutex);
1206
1207		if (err) {
1208			ubifs_ro_mode(c, err);
1209			return err;
1210		}
1211	}
1212	return 0;
1213}