2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 * Copyright (C) 2006, 2007 University of Szeged, Hungary
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published by
9 * the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc., 51
18 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * Authors: Artem Bityutskiy (Битюцкий Артём)
26 * This file implements UBIFS I/O subsystem which provides various I/O-related
27 * helper functions (reading/writing/checking/validating nodes) and implements
28 * write-buffering support. Write buffers help to save space which otherwise
29 * would have been wasted for padding to the nearest minimal I/O unit boundary.
30 * Instead, data first goes to the write-buffer and is flushed when the
31 * buffer is full or when it is not used for some time (by timer). This is
32 * similar to the mechanism is used by JFFS2.
34 * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by
35 * mutexes defined inside these objects. Since sometimes upper-level code
36 * has to lock the write-buffer (e.g. journal space reservation code), many
37 * functions related to write-buffers have "nolock" suffix which means that the
38 * caller has to lock the write-buffer before calling this function.
40 * UBIFS stores nodes at 64 bit-aligned addresses. If the node length is not
41 * aligned, UBIFS starts the next node from the aligned address, and the padded
42 * bytes may contain any rubbish. In other words, UBIFS does not put padding
43 * bytes in those small gaps. Common headers of nodes store real node lengths,
44 * not aligned lengths. Indexing nodes also store real lengths in branches.
46 * UBIFS uses padding when it pads to the next min. I/O unit. In this case it
47 * uses padding nodes or padding bytes, if the padding node does not fit.
49 * All UBIFS nodes are protected by CRC checksums and UBIFS checks all nodes
50 * every time they are read from the flash media.
53 #include <linux/crc32.h>
54 #include <linux/slab.h>
58 * ubifs_ro_mode - switch UBIFS to read read-only mode.
59 * @c: UBIFS file-system description object
60 * @err: error code which is the reason of switching to R/O mode
62 void ubifs_ro_mode(struct ubifs_info *c, int err)
66 c->no_chk_data_crc = 0;
67 c->vfs_sb->s_flags |= MS_RDONLY;
68 ubifs_warn("switched to read-only mode, error %d", err);
74 * ubifs_check_node - check node.
75 * @c: UBIFS file-system description object
77 * @lnum: logical eraseblock number
78 * @offs: offset within the logical eraseblock
79 * @quiet: print no messages
80 * @must_chk_crc: indicates whether to always check the CRC
82 * This function checks node magic number and CRC checksum. This function also
83 * validates node length to prevent UBIFS from becoming crazy when an attacker
84 * feeds it a file-system image with incorrect nodes. For example, too large
85 * node length in the common header could cause UBIFS to read memory outside of
86 * allocated buffer when checking the CRC checksum.
88 * This function may skip data nodes CRC checking if @c->no_chk_data_crc is
89 * true, which is controlled by corresponding UBIFS mount option. However, if
90 * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
91 * checked. Similarly, if @c->always_chk_crc is true, @c->no_chk_data_crc is
92 * ignored and CRC is checked.
94 * This function returns zero in case of success and %-EUCLEAN in case of bad
97 int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
98 int offs, int quiet, int must_chk_crc)
100 int err = -EINVAL, type, node_len;
101 uint32_t crc, node_crc, magic;
102 const struct ubifs_ch *ch = buf;
104 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
105 ubifs_assert(!(offs & 7) && offs < c->leb_size);
107 magic = le32_to_cpu(ch->magic);
108 if (magic != UBIFS_NODE_MAGIC) {
110 ubifs_err("bad magic %#08x, expected %#08x",
111 magic, UBIFS_NODE_MAGIC);
116 type = ch->node_type;
117 if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
119 ubifs_err("bad node type %d", type);
123 node_len = le32_to_cpu(ch->len);
124 if (node_len + offs > c->leb_size)
127 if (c->ranges[type].max_len == 0) {
128 if (node_len != c->ranges[type].len)
130 } else if (node_len < c->ranges[type].min_len ||
131 node_len > c->ranges[type].max_len)
134 if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc &&
138 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
139 node_crc = le32_to_cpu(ch->crc);
140 if (crc != node_crc) {
142 ubifs_err("bad CRC: calculated %#08x, read %#08x",
152 ubifs_err("bad node length %d", node_len);
155 ubifs_err("bad node at LEB %d:%d", lnum, offs);
156 dbg_dump_node(c, buf);
163 * ubifs_pad - pad flash space.
164 * @c: UBIFS file-system description object
165 * @buf: buffer to put padding to
166 * @pad: how many bytes to pad
168 * The flash media obliges us to write only in chunks of %c->min_io_size and
169 * when we have to write less data we add padding node to the write-buffer and
170 * pad it to the next minimal I/O unit's boundary. Padding nodes help when the
171 * media is being scanned. If the amount of wasted space is not enough to fit a
172 * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes
173 * pattern (%UBIFS_PADDING_BYTE).
175 * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is
178 void ubifs_pad(const struct ubifs_info *c, void *buf, int pad)
182 ubifs_assert(pad >= 0 && !(pad & 7));
184 if (pad >= UBIFS_PAD_NODE_SZ) {
185 struct ubifs_ch *ch = buf;
186 struct ubifs_pad_node *pad_node = buf;
188 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
189 ch->node_type = UBIFS_PAD_NODE;
190 ch->group_type = UBIFS_NO_NODE_GROUP;
191 ch->padding[0] = ch->padding[1] = 0;
193 ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ);
194 pad -= UBIFS_PAD_NODE_SZ;
195 pad_node->pad_len = cpu_to_le32(pad);
196 crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8);
197 ch->crc = cpu_to_le32(crc);
198 memset(buf + UBIFS_PAD_NODE_SZ, 0, pad);
200 /* Too little space, padding node won't fit */
201 memset(buf, UBIFS_PADDING_BYTE, pad);
205 * next_sqnum - get next sequence number.
206 * @c: UBIFS file-system description object
208 static unsigned long long next_sqnum(struct ubifs_info *c)
210 unsigned long long sqnum;
212 spin_lock(&c->cnt_lock);
213 sqnum = ++c->max_sqnum;
214 spin_unlock(&c->cnt_lock);
216 if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) {
217 if (sqnum >= SQNUM_WATERMARK) {
218 ubifs_err("sequence number overflow %llu, end of life",
220 ubifs_ro_mode(c, -EINVAL);
222 ubifs_warn("running out of sequence numbers, end of life soon");
229 * ubifs_prepare_node - prepare node to be written to flash.
230 * @c: UBIFS file-system description object
231 * @node: the node to pad
233 * @pad: if the buffer has to be padded
235 * This function prepares node at @node to be written to the media - it
236 * calculates node CRC, fills the common header, and adds proper padding up to
237 * the next minimum I/O unit if @pad is not zero.
239 void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
242 struct ubifs_ch *ch = node;
243 unsigned long long sqnum = next_sqnum(c);
245 ubifs_assert(len >= UBIFS_CH_SZ);
247 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
248 ch->len = cpu_to_le32(len);
249 ch->group_type = UBIFS_NO_NODE_GROUP;
250 ch->sqnum = cpu_to_le64(sqnum);
251 ch->padding[0] = ch->padding[1] = 0;
252 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
253 ch->crc = cpu_to_le32(crc);
257 pad = ALIGN(len, c->min_io_size) - len;
258 ubifs_pad(c, node + len, pad);
263 * ubifs_prep_grp_node - prepare node of a group to be written to flash.
264 * @c: UBIFS file-system description object
265 * @node: the node to pad
267 * @last: indicates the last node of the group
269 * This function prepares node at @node to be written to the media - it
270 * calculates node CRC and fills the common header.
272 void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last)
275 struct ubifs_ch *ch = node;
276 unsigned long long sqnum = next_sqnum(c);
278 ubifs_assert(len >= UBIFS_CH_SZ);
280 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
281 ch->len = cpu_to_le32(len);
283 ch->group_type = UBIFS_LAST_OF_NODE_GROUP;
285 ch->group_type = UBIFS_IN_NODE_GROUP;
286 ch->sqnum = cpu_to_le64(sqnum);
287 ch->padding[0] = ch->padding[1] = 0;
288 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
289 ch->crc = cpu_to_le32(crc);
293 * wbuf_timer_callback - write-buffer timer callback function.
294 * @data: timer data (write-buffer descriptor)
296 * This function is called when the write-buffer timer expires.
298 static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer)
300 struct ubifs_wbuf *wbuf = container_of(timer, struct ubifs_wbuf, timer);
302 dbg_io("jhead %s", dbg_jhead(wbuf->jhead));
304 wbuf->c->need_wbuf_sync = 1;
305 ubifs_wake_up_bgt(wbuf->c);
306 return HRTIMER_NORESTART;
310 * new_wbuf_timer - start new write-buffer timer.
311 * @wbuf: write-buffer descriptor
313 static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
315 ubifs_assert(!hrtimer_active(&wbuf->timer));
319 dbg_io("set timer for jhead %s, %llu-%llu millisecs",
320 dbg_jhead(wbuf->jhead),
321 div_u64(ktime_to_ns(wbuf->softlimit), USEC_PER_SEC),
322 div_u64(ktime_to_ns(wbuf->softlimit) + wbuf->delta,
324 hrtimer_start_range_ns(&wbuf->timer, wbuf->softlimit, wbuf->delta,
329 * cancel_wbuf_timer - cancel write-buffer timer.
330 * @wbuf: write-buffer descriptor
332 static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
337 hrtimer_cancel(&wbuf->timer);
341 * ubifs_wbuf_sync_nolock - synchronize write-buffer.
342 * @wbuf: write-buffer to synchronize
344 * This function synchronizes write-buffer @buf and returns zero in case of
345 * success or a negative error code in case of failure.
347 int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)
349 struct ubifs_info *c = wbuf->c;
352 cancel_wbuf_timer_nolock(wbuf);
353 if (!wbuf->used || wbuf->lnum == -1)
354 /* Write-buffer is empty or not seeked */
357 dbg_io("LEB %d:%d, %d bytes, jhead %s",
358 wbuf->lnum, wbuf->offs, wbuf->used, dbg_jhead(wbuf->jhead));
359 ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY));
360 ubifs_assert(!(wbuf->avail & 7));
361 ubifs_assert(wbuf->offs + c->min_io_size <= c->leb_size);
366 ubifs_pad(c, wbuf->buf + wbuf->used, wbuf->avail);
367 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs,
368 c->min_io_size, wbuf->dtype);
370 ubifs_err("cannot write %d bytes to LEB %d:%d",
371 c->min_io_size, wbuf->lnum, wbuf->offs);
378 spin_lock(&wbuf->lock);
379 wbuf->offs += c->min_io_size;
380 wbuf->avail = c->min_io_size;
383 spin_unlock(&wbuf->lock);
385 if (wbuf->sync_callback)
386 err = wbuf->sync_callback(c, wbuf->lnum,
387 c->leb_size - wbuf->offs, dirt);
392 * ubifs_wbuf_seek_nolock - seek write-buffer.
393 * @wbuf: write-buffer
394 * @lnum: logical eraseblock number to seek to
395 * @offs: logical eraseblock offset to seek to
398 * This function targets the write-buffer to logical eraseblock @lnum:@offs.
399 * The write-buffer is synchronized if it is not empty. Returns zero in case of
400 * success and a negative error code in case of failure.
402 int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs,
405 const struct ubifs_info *c = wbuf->c;
407 dbg_io("LEB %d:%d, jhead %s", lnum, offs, dbg_jhead(wbuf->jhead));
408 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt);
409 ubifs_assert(offs >= 0 && offs <= c->leb_size);
410 ubifs_assert(offs % c->min_io_size == 0 && !(offs & 7));
411 ubifs_assert(lnum != wbuf->lnum);
413 if (wbuf->used > 0) {
414 int err = ubifs_wbuf_sync_nolock(wbuf);
420 spin_lock(&wbuf->lock);
423 wbuf->avail = c->min_io_size;
425 spin_unlock(&wbuf->lock);
432 * ubifs_bg_wbufs_sync - synchronize write-buffers.
433 * @c: UBIFS file-system description object
435 * This function is called by background thread to synchronize write-buffers.
436 * Returns zero in case of success and a negative error code in case of
439 int ubifs_bg_wbufs_sync(struct ubifs_info *c)
443 if (!c->need_wbuf_sync)
445 c->need_wbuf_sync = 0;
452 dbg_io("synchronize");
453 for (i = 0; i < c->jhead_cnt; i++) {
454 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
459 * If the mutex is locked then wbuf is being changed, so
460 * synchronization is not necessary.
462 if (mutex_is_locked(&wbuf->io_mutex))
465 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
466 if (!wbuf->need_sync) {
467 mutex_unlock(&wbuf->io_mutex);
471 err = ubifs_wbuf_sync_nolock(wbuf);
472 mutex_unlock(&wbuf->io_mutex);
474 ubifs_err("cannot sync write-buffer, error %d", err);
475 ubifs_ro_mode(c, err);
483 /* Cancel all timers to prevent repeated errors */
484 for (i = 0; i < c->jhead_cnt; i++) {
485 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
487 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
488 cancel_wbuf_timer_nolock(wbuf);
489 mutex_unlock(&wbuf->io_mutex);
495 * ubifs_wbuf_write_nolock - write data to flash via write-buffer.
496 * @wbuf: write-buffer
497 * @buf: node to write
500 * This function writes data to flash via write-buffer @wbuf. This means that
501 * the last piece of the node won't reach the flash media immediately if it
502 * does not take whole minimal I/O unit. Instead, the node will sit in RAM
503 * until the write-buffer is synchronized (e.g., by timer).
505 * This function returns zero in case of success and a negative error code in
506 * case of failure. If the node cannot be written because there is no more
507 * space in this logical eraseblock, %-ENOSPC is returned.
509 int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
511 struct ubifs_info *c = wbuf->c;
512 int err, written, n, aligned_len = ALIGN(len, 8), offs;
514 dbg_io("%d bytes (%s) to jhead %s wbuf at LEB %d:%d", len,
515 dbg_ntype(((struct ubifs_ch *)buf)->node_type),
516 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs + wbuf->used);
517 ubifs_assert(len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);
518 ubifs_assert(wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);
519 ubifs_assert(!(wbuf->offs & 7) && wbuf->offs <= c->leb_size);
520 ubifs_assert(wbuf->avail > 0 && wbuf->avail <= c->min_io_size);
521 ubifs_assert(mutex_is_locked(&wbuf->io_mutex));
523 if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {
528 cancel_wbuf_timer_nolock(wbuf);
533 if (aligned_len <= wbuf->avail) {
535 * The node is not very large and fits entirely within
538 memcpy(wbuf->buf + wbuf->used, buf, len);
540 if (aligned_len == wbuf->avail) {
541 dbg_io("flush jhead %s wbuf to LEB %d:%d",
542 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
543 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf,
544 wbuf->offs, c->min_io_size,
549 spin_lock(&wbuf->lock);
550 wbuf->offs += c->min_io_size;
551 wbuf->avail = c->min_io_size;
554 spin_unlock(&wbuf->lock);
556 spin_lock(&wbuf->lock);
557 wbuf->avail -= aligned_len;
558 wbuf->used += aligned_len;
559 spin_unlock(&wbuf->lock);
566 * The node is large enough and does not fit entirely within current
567 * minimal I/O unit. We have to fill and flush write-buffer and switch
568 * to the next min. I/O unit.
570 dbg_io("flush jhead %s wbuf to LEB %d:%d",
571 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
572 memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);
573 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs,
574 c->min_io_size, wbuf->dtype);
578 offs = wbuf->offs + c->min_io_size;
580 aligned_len -= wbuf->avail;
581 written = wbuf->avail;
584 * The remaining data may take more whole min. I/O units, so write the
585 * remains multiple to min. I/O unit size directly to the flash media.
586 * We align node length to 8-byte boundary because we anyway flash wbuf
587 * if the remaining space is less than 8 bytes.
589 n = aligned_len >> c->min_io_shift;
591 n <<= c->min_io_shift;
592 dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, offs);
593 err = ubi_leb_write(c->ubi, wbuf->lnum, buf + written, offs, n,
603 spin_lock(&wbuf->lock);
606 * And now we have what's left and what does not take whole
607 * min. I/O unit, so write it to the write-buffer and we are
610 memcpy(wbuf->buf, buf + written, len);
613 wbuf->used = aligned_len;
614 wbuf->avail = c->min_io_size - aligned_len;
616 spin_unlock(&wbuf->lock);
619 if (wbuf->sync_callback) {
620 int free = c->leb_size - wbuf->offs - wbuf->used;
622 err = wbuf->sync_callback(c, wbuf->lnum, free, 0);
628 new_wbuf_timer_nolock(wbuf);
633 ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
634 len, wbuf->lnum, wbuf->offs, err);
635 dbg_dump_node(c, buf);
637 dbg_dump_leb(c, wbuf->lnum);
642 * ubifs_write_node - write node to the media.
643 * @c: UBIFS file-system description object
644 * @buf: the node to write
646 * @lnum: logical eraseblock number
647 * @offs: offset within the logical eraseblock
648 * @dtype: node life-time hint (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
650 * This function automatically fills node magic number, assigns sequence
651 * number, and calculates node CRC checksum. The length of the @buf buffer has
652 * to be aligned to the minimal I/O unit size. This function automatically
653 * appends padding node and padding bytes if needed. Returns zero in case of
654 * success and a negative error code in case of failure.
656 int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
659 int err, buf_len = ALIGN(len, c->min_io_size);
661 dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
662 lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
664 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
665 ubifs_assert(offs % c->min_io_size == 0 && offs < c->leb_size);
670 ubifs_prepare_node(c, buf, len, 1);
671 err = ubi_leb_write(c->ubi, lnum, buf, offs, buf_len, dtype);
673 ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
674 buf_len, lnum, offs, err);
675 dbg_dump_node(c, buf);
683 * ubifs_read_node_wbuf - read node from the media or write-buffer.
684 * @wbuf: wbuf to check for un-written data
685 * @buf: buffer to read to
688 * @lnum: logical eraseblock number
689 * @offs: offset within the logical eraseblock
691 * This function reads a node of known type and length, checks it and stores
692 * in @buf. If the node partially or fully sits in the write-buffer, this
693 * function takes data from the buffer, otherwise it reads the flash media.
694 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
695 * error code in case of failure.
697 int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
700 const struct ubifs_info *c = wbuf->c;
701 int err, rlen, overlap;
702 struct ubifs_ch *ch = buf;
704 dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs,
705 dbg_ntype(type), len, dbg_jhead(wbuf->jhead));
706 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
707 ubifs_assert(!(offs & 7) && offs < c->leb_size);
708 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
710 spin_lock(&wbuf->lock);
711 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
713 /* We may safely unlock the write-buffer and read the data */
714 spin_unlock(&wbuf->lock);
715 return ubifs_read_node(c, buf, type, len, lnum, offs);
718 /* Don't read under wbuf */
719 rlen = wbuf->offs - offs;
723 /* Copy the rest from the write-buffer */
724 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
725 spin_unlock(&wbuf->lock);
728 /* Read everything that goes before write-buffer */
729 err = ubi_read(c->ubi, lnum, buf, offs, rlen);
730 if (err && err != -EBADMSG) {
731 ubifs_err("failed to read node %d from LEB %d:%d, "
732 "error %d", type, lnum, offs, err);
738 if (type != ch->node_type) {
739 ubifs_err("bad node type (%d but expected %d)",
740 ch->node_type, type);
744 err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
746 ubifs_err("expected node type %d", type);
750 rlen = le32_to_cpu(ch->len);
752 ubifs_err("bad node length %d, expected %d", rlen, len);
759 ubifs_err("bad node at LEB %d:%d", lnum, offs);
760 dbg_dump_node(c, buf);
766 * ubifs_read_node - read node.
767 * @c: UBIFS file-system description object
768 * @buf: buffer to read to
770 * @len: node length (not aligned)
771 * @lnum: logical eraseblock number
772 * @offs: offset within the logical eraseblock
774 * This function reads a node of known type and and length, checks it and
775 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
776 * and a negative error code in case of failure.
778 int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
782 struct ubifs_ch *ch = buf;
784 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
785 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
786 ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
787 ubifs_assert(!(offs & 7) && offs < c->leb_size);
788 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
790 err = ubi_read(c->ubi, lnum, buf, offs, len);
791 if (err && err != -EBADMSG) {
792 ubifs_err("cannot read node %d from LEB %d:%d, error %d",
793 type, lnum, offs, err);
797 if (type != ch->node_type) {
798 ubifs_err("bad node type (%d but expected %d)",
799 ch->node_type, type);
803 err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
805 ubifs_err("expected node type %d", type);
809 l = le32_to_cpu(ch->len);
811 ubifs_err("bad node length %d, expected %d", l, len);
818 ubifs_err("bad node at LEB %d:%d", lnum, offs);
819 dbg_dump_node(c, buf);
825 * ubifs_wbuf_init - initialize write-buffer.
826 * @c: UBIFS file-system description object
827 * @wbuf: write-buffer to initialize
829 * This function initializes write-buffer. Returns zero in case of success
830 * %-ENOMEM in case of failure.
832 int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
836 wbuf->buf = kmalloc(c->min_io_size, GFP_KERNEL);
840 size = (c->min_io_size / UBIFS_CH_SZ + 1) * sizeof(ino_t);
841 wbuf->inodes = kmalloc(size, GFP_KERNEL);
849 wbuf->lnum = wbuf->offs = -1;
850 wbuf->avail = c->min_io_size;
851 wbuf->dtype = UBI_UNKNOWN;
852 wbuf->sync_callback = NULL;
853 mutex_init(&wbuf->io_mutex);
854 spin_lock_init(&wbuf->lock);
858 hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
859 wbuf->timer.function = wbuf_timer_callback_nolock;
860 wbuf->softlimit = ktime_set(WBUF_TIMEOUT_SOFTLIMIT, 0);
861 wbuf->delta = WBUF_TIMEOUT_HARDLIMIT - WBUF_TIMEOUT_SOFTLIMIT;
862 wbuf->delta *= 1000000000ULL;
863 ubifs_assert(wbuf->delta <= ULONG_MAX);
868 * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array.
869 * @wbuf: the write-buffer where to add
870 * @inum: the inode number
872 * This function adds an inode number to the inode array of the write-buffer.
874 void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum)
877 /* NOR flash or something similar */
880 spin_lock(&wbuf->lock);
882 wbuf->inodes[wbuf->next_ino++] = inum;
883 spin_unlock(&wbuf->lock);
887 * wbuf_has_ino - returns if the wbuf contains data from the inode.
888 * @wbuf: the write-buffer
889 * @inum: the inode number
891 * This function returns with %1 if the write-buffer contains some data from the
892 * given inode otherwise it returns with %0.
894 static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum)
898 spin_lock(&wbuf->lock);
899 for (i = 0; i < wbuf->next_ino; i++)
900 if (inum == wbuf->inodes[i]) {
904 spin_unlock(&wbuf->lock);
910 * ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode.
911 * @c: UBIFS file-system description object
912 * @inode: inode to synchronize
914 * This function synchronizes write-buffers which contain nodes belonging to
915 * @inode. Returns zero in case of success and a negative error code in case of
918 int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)
922 for (i = 0; i < c->jhead_cnt; i++) {
923 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
927 * GC head is special, do not look at it. Even if the
928 * head contains something related to this inode, it is
929 * a _copy_ of corresponding on-flash node which sits
934 if (!wbuf_has_ino(wbuf, inode->i_ino))
937 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
938 if (wbuf_has_ino(wbuf, inode->i_ino))
939 err = ubifs_wbuf_sync_nolock(wbuf);
940 mutex_unlock(&wbuf->io_mutex);
943 ubifs_ro_mode(c, err);