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>
57 * ubifs_ro_mode - switch UBIFS to read read-only mode.
58 * @c: UBIFS file-system description object
59 * @err: error code which is the reason of switching to R/O mode
61 void ubifs_ro_mode(struct ubifs_info *c, int err)
65 c->no_chk_data_crc = 0;
66 ubifs_warn("switched to read-only mode, error %d", err);
72 * ubifs_check_node - check node.
73 * @c: UBIFS file-system description object
75 * @lnum: logical eraseblock number
76 * @offs: offset within the logical eraseblock
77 * @quiet: print no messages
78 * @must_chk_crc: indicates whether to always check the CRC
80 * This function checks node magic number and CRC checksum. This function also
81 * validates node length to prevent UBIFS from becoming crazy when an attacker
82 * feeds it a file-system image with incorrect nodes. For example, too large
83 * node length in the common header could cause UBIFS to read memory outside of
84 * allocated buffer when checking the CRC checksum.
86 * This function may skip data nodes CRC checking if @c->no_chk_data_crc is
87 * true, which is controlled by corresponding UBIFS mount option. However, if
88 * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
89 * checked. Similarly, if @c->always_chk_crc is true, @c->no_chk_data_crc is
90 * ignored and CRC is checked.
92 * This function returns zero in case of success and %-EUCLEAN in case of bad
95 int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
96 int offs, int quiet, int must_chk_crc)
98 int err = -EINVAL, type, node_len;
99 uint32_t crc, node_crc, magic;
100 const struct ubifs_ch *ch = buf;
102 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
103 ubifs_assert(!(offs & 7) && offs < c->leb_size);
105 magic = le32_to_cpu(ch->magic);
106 if (magic != UBIFS_NODE_MAGIC) {
108 ubifs_err("bad magic %#08x, expected %#08x",
109 magic, UBIFS_NODE_MAGIC);
114 type = ch->node_type;
115 if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
117 ubifs_err("bad node type %d", type);
121 node_len = le32_to_cpu(ch->len);
122 if (node_len + offs > c->leb_size)
125 if (c->ranges[type].max_len == 0) {
126 if (node_len != c->ranges[type].len)
128 } else if (node_len < c->ranges[type].min_len ||
129 node_len > c->ranges[type].max_len)
132 if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc &&
136 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
137 node_crc = le32_to_cpu(ch->crc);
138 if (crc != node_crc) {
140 ubifs_err("bad CRC: calculated %#08x, read %#08x",
150 ubifs_err("bad node length %d", node_len);
153 ubifs_err("bad node at LEB %d:%d", lnum, offs);
154 dbg_dump_node(c, buf);
161 * ubifs_pad - pad flash space.
162 * @c: UBIFS file-system description object
163 * @buf: buffer to put padding to
164 * @pad: how many bytes to pad
166 * The flash media obliges us to write only in chunks of %c->min_io_size and
167 * when we have to write less data we add padding node to the write-buffer and
168 * pad it to the next minimal I/O unit's boundary. Padding nodes help when the
169 * media is being scanned. If the amount of wasted space is not enough to fit a
170 * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes
171 * pattern (%UBIFS_PADDING_BYTE).
173 * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is
176 void ubifs_pad(const struct ubifs_info *c, void *buf, int pad)
180 ubifs_assert(pad >= 0 && !(pad & 7));
182 if (pad >= UBIFS_PAD_NODE_SZ) {
183 struct ubifs_ch *ch = buf;
184 struct ubifs_pad_node *pad_node = buf;
186 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
187 ch->node_type = UBIFS_PAD_NODE;
188 ch->group_type = UBIFS_NO_NODE_GROUP;
189 ch->padding[0] = ch->padding[1] = 0;
191 ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ);
192 pad -= UBIFS_PAD_NODE_SZ;
193 pad_node->pad_len = cpu_to_le32(pad);
194 crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8);
195 ch->crc = cpu_to_le32(crc);
196 memset(buf + UBIFS_PAD_NODE_SZ, 0, pad);
198 /* Too little space, padding node won't fit */
199 memset(buf, UBIFS_PADDING_BYTE, pad);
203 * next_sqnum - get next sequence number.
204 * @c: UBIFS file-system description object
206 static unsigned long long next_sqnum(struct ubifs_info *c)
208 unsigned long long sqnum;
210 spin_lock(&c->cnt_lock);
211 sqnum = ++c->max_sqnum;
212 spin_unlock(&c->cnt_lock);
214 if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) {
215 if (sqnum >= SQNUM_WATERMARK) {
216 ubifs_err("sequence number overflow %llu, end of life",
218 ubifs_ro_mode(c, -EINVAL);
220 ubifs_warn("running out of sequence numbers, end of life soon");
227 * ubifs_prepare_node - prepare node to be written to flash.
228 * @c: UBIFS file-system description object
229 * @node: the node to pad
231 * @pad: if the buffer has to be padded
233 * This function prepares node at @node to be written to the media - it
234 * calculates node CRC, fills the common header, and adds proper padding up to
235 * the next minimum I/O unit if @pad is not zero.
237 void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
240 struct ubifs_ch *ch = node;
241 unsigned long long sqnum = next_sqnum(c);
243 ubifs_assert(len >= UBIFS_CH_SZ);
245 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
246 ch->len = cpu_to_le32(len);
247 ch->group_type = UBIFS_NO_NODE_GROUP;
248 ch->sqnum = cpu_to_le64(sqnum);
249 ch->padding[0] = ch->padding[1] = 0;
250 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
251 ch->crc = cpu_to_le32(crc);
255 pad = ALIGN(len, c->min_io_size) - len;
256 ubifs_pad(c, node + len, pad);
261 * ubifs_prep_grp_node - prepare node of a group to be written to flash.
262 * @c: UBIFS file-system description object
263 * @node: the node to pad
265 * @last: indicates the last node of the group
267 * This function prepares node at @node to be written to the media - it
268 * calculates node CRC and fills the common header.
270 void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last)
273 struct ubifs_ch *ch = node;
274 unsigned long long sqnum = next_sqnum(c);
276 ubifs_assert(len >= UBIFS_CH_SZ);
278 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
279 ch->len = cpu_to_le32(len);
281 ch->group_type = UBIFS_LAST_OF_NODE_GROUP;
283 ch->group_type = UBIFS_IN_NODE_GROUP;
284 ch->sqnum = cpu_to_le64(sqnum);
285 ch->padding[0] = ch->padding[1] = 0;
286 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
287 ch->crc = cpu_to_le32(crc);
291 * wbuf_timer_callback - write-buffer timer callback function.
292 * @data: timer data (write-buffer descriptor)
294 * This function is called when the write-buffer timer expires.
296 static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer)
298 struct ubifs_wbuf *wbuf = container_of(timer, struct ubifs_wbuf, timer);
300 dbg_io("jhead %d", wbuf->jhead);
302 wbuf->c->need_wbuf_sync = 1;
303 ubifs_wake_up_bgt(wbuf->c);
304 return HRTIMER_NORESTART;
308 * new_wbuf_timer - start new write-buffer timer.
309 * @wbuf: write-buffer descriptor
311 static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
313 ubifs_assert(!hrtimer_active(&wbuf->timer));
315 if (!ktime_to_ns(wbuf->softlimit))
317 dbg_io("set timer for jhead %d, %llu-%llu millisecs", wbuf->jhead,
318 ktime_to_ns(wbuf->softlimit)/USEC_PER_SEC,
319 (ktime_to_ns(wbuf->softlimit) + wbuf->delta)/USEC_PER_SEC);
320 hrtimer_start_range_ns(&wbuf->timer, wbuf->softlimit, wbuf->delta,
325 * cancel_wbuf_timer - cancel write-buffer timer.
326 * @wbuf: write-buffer descriptor
328 static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
331 * If the syncer is waiting for the lock (from the background thread's
332 * context) and another task is changing write-buffer then the syncing
333 * should be canceled.
336 hrtimer_cancel(&wbuf->timer);
340 * ubifs_wbuf_sync_nolock - synchronize write-buffer.
341 * @wbuf: write-buffer to synchronize
343 * This function synchronizes write-buffer @buf and returns zero in case of
344 * success or a negative error code in case of failure.
346 int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)
348 struct ubifs_info *c = wbuf->c;
351 cancel_wbuf_timer_nolock(wbuf);
352 if (!wbuf->used || wbuf->lnum == -1)
353 /* Write-buffer is empty or not seeked */
356 dbg_io("LEB %d:%d, %d bytes, jhead %d",
357 wbuf->lnum, wbuf->offs, wbuf->used, wbuf->jhead);
358 ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY));
359 ubifs_assert(!(wbuf->avail & 7));
360 ubifs_assert(wbuf->offs + c->min_io_size <= c->leb_size);
365 ubifs_pad(c, wbuf->buf + wbuf->used, wbuf->avail);
366 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs,
367 c->min_io_size, wbuf->dtype);
369 ubifs_err("cannot write %d bytes to LEB %d:%d",
370 c->min_io_size, wbuf->lnum, wbuf->offs);
377 spin_lock(&wbuf->lock);
378 wbuf->offs += c->min_io_size;
379 wbuf->avail = c->min_io_size;
382 spin_unlock(&wbuf->lock);
384 if (wbuf->sync_callback)
385 err = wbuf->sync_callback(c, wbuf->lnum,
386 c->leb_size - wbuf->offs, dirt);
391 * ubifs_wbuf_seek_nolock - seek write-buffer.
392 * @wbuf: write-buffer
393 * @lnum: logical eraseblock number to seek to
394 * @offs: logical eraseblock offset to seek to
397 * This function targets the write buffer to logical eraseblock @lnum:@offs.
398 * The write-buffer is synchronized if it is not empty. Returns zero in case of
399 * success and a negative error code in case of failure.
401 int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs,
404 const struct ubifs_info *c = wbuf->c;
406 dbg_io("LEB %d:%d, jhead %d", lnum, offs, wbuf->jhead);
407 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt);
408 ubifs_assert(offs >= 0 && offs <= c->leb_size);
409 ubifs_assert(offs % c->min_io_size == 0 && !(offs & 7));
410 ubifs_assert(lnum != wbuf->lnum);
412 if (wbuf->used > 0) {
413 int err = ubifs_wbuf_sync_nolock(wbuf);
419 spin_lock(&wbuf->lock);
422 wbuf->avail = c->min_io_size;
424 spin_unlock(&wbuf->lock);
431 * ubifs_bg_wbufs_sync - synchronize write-buffers.
432 * @c: UBIFS file-system description object
434 * This function is called by background thread to synchronize write-buffers.
435 * Returns zero in case of success and a negative error code in case of
438 int ubifs_bg_wbufs_sync(struct ubifs_info *c)
442 if (!c->need_wbuf_sync)
444 c->need_wbuf_sync = 0;
451 dbg_io("synchronize");
452 for (i = 0; i < c->jhead_cnt; i++) {
453 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
458 * If the mutex is locked then wbuf is being changed, so
459 * synchronization is not necessary.
461 if (mutex_is_locked(&wbuf->io_mutex))
464 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
465 if (!wbuf->need_sync) {
466 mutex_unlock(&wbuf->io_mutex);
470 err = ubifs_wbuf_sync_nolock(wbuf);
471 mutex_unlock(&wbuf->io_mutex);
473 ubifs_err("cannot sync write-buffer, error %d", err);
474 ubifs_ro_mode(c, err);
482 /* Cancel all timers to prevent repeated errors */
483 for (i = 0; i < c->jhead_cnt; i++) {
484 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
486 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
487 cancel_wbuf_timer_nolock(wbuf);
488 mutex_unlock(&wbuf->io_mutex);
494 * ubifs_wbuf_write_nolock - write data to flash via write-buffer.
495 * @wbuf: write-buffer
496 * @buf: node to write
499 * This function writes data to flash via write-buffer @wbuf. This means that
500 * the last piece of the node won't reach the flash media immediately if it
501 * does not take whole minimal I/O unit. Instead, the node will sit in RAM
502 * until the write-buffer is synchronized (e.g., by timer).
504 * This function returns zero in case of success and a negative error code in
505 * case of failure. If the node cannot be written because there is no more
506 * space in this logical eraseblock, %-ENOSPC is returned.
508 int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
510 struct ubifs_info *c = wbuf->c;
511 int err, written, n, aligned_len = ALIGN(len, 8), offs;
513 dbg_io("%d bytes (%s) to jhead %d wbuf at LEB %d:%d", len,
514 dbg_ntype(((struct ubifs_ch *)buf)->node_type), wbuf->jhead,
515 wbuf->lnum, wbuf->offs + wbuf->used);
516 ubifs_assert(len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);
517 ubifs_assert(wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);
518 ubifs_assert(!(wbuf->offs & 7) && wbuf->offs <= c->leb_size);
519 ubifs_assert(wbuf->avail > 0 && wbuf->avail <= c->min_io_size);
520 ubifs_assert(mutex_is_locked(&wbuf->io_mutex));
522 if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {
527 cancel_wbuf_timer_nolock(wbuf);
532 if (aligned_len <= wbuf->avail) {
534 * The node is not very large and fits entirely within
537 memcpy(wbuf->buf + wbuf->used, buf, len);
539 if (aligned_len == wbuf->avail) {
540 dbg_io("flush jhead %d wbuf to LEB %d:%d",
541 wbuf->jhead, wbuf->lnum, wbuf->offs);
542 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf,
543 wbuf->offs, c->min_io_size,
548 spin_lock(&wbuf->lock);
549 wbuf->offs += c->min_io_size;
550 wbuf->avail = c->min_io_size;
553 spin_unlock(&wbuf->lock);
555 spin_lock(&wbuf->lock);
556 wbuf->avail -= aligned_len;
557 wbuf->used += aligned_len;
558 spin_unlock(&wbuf->lock);
565 * The node is large enough and does not fit entirely within current
566 * minimal I/O unit. We have to fill and flush write-buffer and switch
567 * to the next min. I/O unit.
569 dbg_io("flush jhead %d wbuf to LEB %d:%d",
570 wbuf->jhead, wbuf->lnum, wbuf->offs);
571 memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);
572 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs,
573 c->min_io_size, wbuf->dtype);
577 offs = wbuf->offs + c->min_io_size;
579 aligned_len -= wbuf->avail;
580 written = wbuf->avail;
583 * The remaining data may take more whole min. I/O units, so write the
584 * remains multiple to min. I/O unit size directly to the flash media.
585 * We align node length to 8-byte boundary because we anyway flash wbuf
586 * if the remaining space is less than 8 bytes.
588 n = aligned_len >> c->min_io_shift;
590 n <<= c->min_io_shift;
591 dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, offs);
592 err = ubi_leb_write(c->ubi, wbuf->lnum, buf + written, offs, n,
602 spin_lock(&wbuf->lock);
605 * And now we have what's left and what does not take whole
606 * min. I/O unit, so write it to the write-buffer and we are
609 memcpy(wbuf->buf, buf + written, len);
612 wbuf->used = aligned_len;
613 wbuf->avail = c->min_io_size - aligned_len;
615 spin_unlock(&wbuf->lock);
618 if (wbuf->sync_callback) {
619 int free = c->leb_size - wbuf->offs - wbuf->used;
621 err = wbuf->sync_callback(c, wbuf->lnum, free, 0);
627 new_wbuf_timer_nolock(wbuf);
632 ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
633 len, wbuf->lnum, wbuf->offs, err);
634 dbg_dump_node(c, buf);
636 dbg_dump_leb(c, wbuf->lnum);
641 * ubifs_write_node - write node to the media.
642 * @c: UBIFS file-system description object
643 * @buf: the node to write
645 * @lnum: logical eraseblock number
646 * @offs: offset within the logical eraseblock
647 * @dtype: node life-time hint (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
649 * This function automatically fills node magic number, assigns sequence
650 * number, and calculates node CRC checksum. The length of the @buf buffer has
651 * to be aligned to the minimal I/O unit size. This function automatically
652 * appends padding node and padding bytes if needed. Returns zero in case of
653 * success and a negative error code in case of failure.
655 int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
658 int err, buf_len = ALIGN(len, c->min_io_size);
660 dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
661 lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
663 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
664 ubifs_assert(offs % c->min_io_size == 0 && offs < c->leb_size);
669 ubifs_prepare_node(c, buf, len, 1);
670 err = ubi_leb_write(c->ubi, lnum, buf, offs, buf_len, dtype);
672 ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
673 buf_len, lnum, offs, err);
674 dbg_dump_node(c, buf);
682 * ubifs_read_node_wbuf - read node from the media or write-buffer.
683 * @wbuf: wbuf to check for un-written data
684 * @buf: buffer to read to
687 * @lnum: logical eraseblock number
688 * @offs: offset within the logical eraseblock
690 * This function reads a node of known type and length, checks it and stores
691 * in @buf. If the node partially or fully sits in the write-buffer, this
692 * function takes data from the buffer, otherwise it reads the flash media.
693 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
694 * error code in case of failure.
696 int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
699 const struct ubifs_info *c = wbuf->c;
700 int err, rlen, overlap;
701 struct ubifs_ch *ch = buf;
703 dbg_io("LEB %d:%d, %s, length %d, jhead %d", lnum, offs,
704 dbg_ntype(type), len, wbuf->jhead);
705 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
706 ubifs_assert(!(offs & 7) && offs < c->leb_size);
707 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
709 spin_lock(&wbuf->lock);
710 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
712 /* We may safely unlock the write-buffer and read the data */
713 spin_unlock(&wbuf->lock);
714 return ubifs_read_node(c, buf, type, len, lnum, offs);
717 /* Don't read under wbuf */
718 rlen = wbuf->offs - offs;
722 /* Copy the rest from the write-buffer */
723 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
724 spin_unlock(&wbuf->lock);
727 /* Read everything that goes before write-buffer */
728 err = ubi_read(c->ubi, lnum, buf, offs, rlen);
729 if (err && err != -EBADMSG) {
730 ubifs_err("failed to read node %d from LEB %d:%d, "
731 "error %d", type, lnum, offs, err);
737 if (type != ch->node_type) {
738 ubifs_err("bad node type (%d but expected %d)",
739 ch->node_type, type);
743 err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
745 ubifs_err("expected node type %d", type);
749 rlen = le32_to_cpu(ch->len);
751 ubifs_err("bad node length %d, expected %d", rlen, len);
758 ubifs_err("bad node at LEB %d:%d", lnum, offs);
759 dbg_dump_node(c, buf);
765 * ubifs_read_node - read node.
766 * @c: UBIFS file-system description object
767 * @buf: buffer to read to
769 * @len: node length (not aligned)
770 * @lnum: logical eraseblock number
771 * @offs: offset within the logical eraseblock
773 * This function reads a node of known type and and length, checks it and
774 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
775 * and a negative error code in case of failure.
777 int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
781 struct ubifs_ch *ch = buf;
783 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
784 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
785 ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
786 ubifs_assert(!(offs & 7) && offs < c->leb_size);
787 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
789 err = ubi_read(c->ubi, lnum, buf, offs, len);
790 if (err && err != -EBADMSG) {
791 ubifs_err("cannot read node %d from LEB %d:%d, error %d",
792 type, lnum, offs, err);
796 if (type != ch->node_type) {
797 ubifs_err("bad node type (%d but expected %d)",
798 ch->node_type, type);
802 err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
804 ubifs_err("expected node type %d", type);
808 l = le32_to_cpu(ch->len);
810 ubifs_err("bad node length %d, expected %d", l, len);
817 ubifs_err("bad node at LEB %d:%d", lnum, offs);
818 dbg_dump_node(c, buf);
824 * ubifs_wbuf_init - initialize write-buffer.
825 * @c: UBIFS file-system description object
826 * @wbuf: write-buffer to initialize
828 * This function initializes write buffer. Returns zero in case of success
829 * %-ENOMEM in case of failure.
831 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;
861 * Make write-buffer soft limit to be 20% of the hard limit. The
862 * write-buffer timer is allowed to expire any time between the soft
865 hardlimit = ktime_set(DEFAULT_WBUF_TIMEOUT_SECS, 0);
866 wbuf->delta = DEFAULT_WBUF_TIMEOUT_SECS * 1000000000ULL * 2 / 10;
867 if (wbuf->delta > ULONG_MAX)
868 wbuf->delta = ULONG_MAX;
869 wbuf->softlimit = ktime_sub_ns(hardlimit, wbuf->delta);
870 hrtimer_set_expires_range_ns(&wbuf->timer, wbuf->softlimit,
876 * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array.
877 * @wbuf: the write-buffer whereto add
878 * @inum: the inode number
880 * This function adds an inode number to the inode array of the write-buffer.
882 void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum)
885 /* NOR flash or something similar */
888 spin_lock(&wbuf->lock);
890 wbuf->inodes[wbuf->next_ino++] = inum;
891 spin_unlock(&wbuf->lock);
895 * wbuf_has_ino - returns if the wbuf contains data from the inode.
896 * @wbuf: the write-buffer
897 * @inum: the inode number
899 * This function returns with %1 if the write-buffer contains some data from the
900 * given inode otherwise it returns with %0.
902 static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum)
906 spin_lock(&wbuf->lock);
907 for (i = 0; i < wbuf->next_ino; i++)
908 if (inum == wbuf->inodes[i]) {
912 spin_unlock(&wbuf->lock);
918 * ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode.
919 * @c: UBIFS file-system description object
920 * @inode: inode to synchronize
922 * This function synchronizes write-buffers which contain nodes belonging to
923 * @inode. Returns zero in case of success and a negative error code in case of
926 int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)
930 for (i = 0; i < c->jhead_cnt; i++) {
931 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
935 * GC head is special, do not look at it. Even if the
936 * head contains something related to this inode, it is
937 * a _copy_ of corresponding on-flash node which sits
942 if (!wbuf_has_ino(wbuf, inode->i_ino))
945 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
946 if (wbuf_has_ino(wbuf, inode->i_ino))
947 err = ubifs_wbuf_sync_nolock(wbuf);
948 mutex_unlock(&wbuf->io_mutex);
951 ubifs_ro_mode(c, err);