blob: 054363f2b207398ff6110fa74a7333d84d43dbc4 [file] [log] [blame]
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 * Copyright (C) 2006, 2007 University of Szeged, Hungary
6 *
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.
10 *
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
14 * more details.
15 *
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
19 *
20 * Authors: Artem Bityutskiy (Битюцкий Артём)
21 * Adrian Hunter
22 * Zoltan Sogor
23 */
24
25/*
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 * similarto the mechanism is used by JFFS2.
33 *
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.
39 *
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.
45 *
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.
48 *
49 * All UBIFS nodes are protected by CRC checksums and UBIFS checks all nodes
50 * every time they are read from the flash media.
51 */
52
53#include <linux/crc32.h>
54#include "ubifs.h"
55
56/**
Adrian Hunterff46d7b2008-07-21 15:39:05 +030057 * 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
60 */
61void ubifs_ro_mode(struct ubifs_info *c, int err)
62{
63 if (!c->ro_media) {
64 c->ro_media = 1;
65 ubifs_warn("switched to read-only mode, error %d", err);
66 dbg_dump_stack();
67 }
68}
69
70/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +030071 * ubifs_check_node - check node.
72 * @c: UBIFS file-system description object
73 * @buf: node to check
74 * @lnum: logical eraseblock number
75 * @offs: offset within the logical eraseblock
76 * @quiet: print no messages
77 *
78 * This function checks node magic number and CRC checksum. This function also
79 * validates node length to prevent UBIFS from becoming crazy when an attacker
80 * feeds it a file-system image with incorrect nodes. For example, too large
81 * node length in the common header could cause UBIFS to read memory outside of
82 * allocated buffer when checking the CRC checksum.
83 *
84 * This function returns zero in case of success %-EUCLEAN in case of bad CRC
85 * or magic.
86 */
87int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
88 int offs, int quiet)
89{
90 int err = -EINVAL, type, node_len;
91 uint32_t crc, node_crc, magic;
92 const struct ubifs_ch *ch = buf;
93
94 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
95 ubifs_assert(!(offs & 7) && offs < c->leb_size);
96
97 magic = le32_to_cpu(ch->magic);
98 if (magic != UBIFS_NODE_MAGIC) {
99 if (!quiet)
100 ubifs_err("bad magic %#08x, expected %#08x",
101 magic, UBIFS_NODE_MAGIC);
102 err = -EUCLEAN;
103 goto out;
104 }
105
106 type = ch->node_type;
107 if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
108 if (!quiet)
109 ubifs_err("bad node type %d", type);
110 goto out;
111 }
112
113 node_len = le32_to_cpu(ch->len);
114 if (node_len + offs > c->leb_size)
115 goto out_len;
116
117 if (c->ranges[type].max_len == 0) {
118 if (node_len != c->ranges[type].len)
119 goto out_len;
120 } else if (node_len < c->ranges[type].min_len ||
121 node_len > c->ranges[type].max_len)
122 goto out_len;
123
124 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
125 node_crc = le32_to_cpu(ch->crc);
126 if (crc != node_crc) {
127 if (!quiet)
128 ubifs_err("bad CRC: calculated %#08x, read %#08x",
129 crc, node_crc);
130 err = -EUCLEAN;
131 goto out;
132 }
133
134 return 0;
135
136out_len:
137 if (!quiet)
138 ubifs_err("bad node length %d", node_len);
139out:
140 if (!quiet) {
141 ubifs_err("bad node at LEB %d:%d", lnum, offs);
142 dbg_dump_node(c, buf);
143 dbg_dump_stack();
144 }
145 return err;
146}
147
148/**
149 * ubifs_pad - pad flash space.
150 * @c: UBIFS file-system description object
151 * @buf: buffer to put padding to
152 * @pad: how many bytes to pad
153 *
154 * The flash media obliges us to write only in chunks of %c->min_io_size and
155 * when we have to write less data we add padding node to the write-buffer and
156 * pad it to the next minimal I/O unit's boundary. Padding nodes help when the
157 * media is being scanned. If the amount of wasted space is not enough to fit a
158 * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes
159 * pattern (%UBIFS_PADDING_BYTE).
160 *
161 * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is
162 * used.
163 */
164void ubifs_pad(const struct ubifs_info *c, void *buf, int pad)
165{
166 uint32_t crc;
167
168 ubifs_assert(pad >= 0 && !(pad & 7));
169
170 if (pad >= UBIFS_PAD_NODE_SZ) {
171 struct ubifs_ch *ch = buf;
172 struct ubifs_pad_node *pad_node = buf;
173
174 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
175 ch->node_type = UBIFS_PAD_NODE;
176 ch->group_type = UBIFS_NO_NODE_GROUP;
177 ch->padding[0] = ch->padding[1] = 0;
178 ch->sqnum = 0;
179 ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ);
180 pad -= UBIFS_PAD_NODE_SZ;
181 pad_node->pad_len = cpu_to_le32(pad);
182 crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8);
183 ch->crc = cpu_to_le32(crc);
184 memset(buf + UBIFS_PAD_NODE_SZ, 0, pad);
185 } else if (pad > 0)
186 /* Too little space, padding node won't fit */
187 memset(buf, UBIFS_PADDING_BYTE, pad);
188}
189
190/**
191 * next_sqnum - get next sequence number.
192 * @c: UBIFS file-system description object
193 */
194static unsigned long long next_sqnum(struct ubifs_info *c)
195{
196 unsigned long long sqnum;
197
198 spin_lock(&c->cnt_lock);
199 sqnum = ++c->max_sqnum;
200 spin_unlock(&c->cnt_lock);
201
202 if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) {
203 if (sqnum >= SQNUM_WATERMARK) {
204 ubifs_err("sequence number overflow %llu, end of life",
205 sqnum);
206 ubifs_ro_mode(c, -EINVAL);
207 }
208 ubifs_warn("running out of sequence numbers, end of life soon");
209 }
210
211 return sqnum;
212}
213
214/**
215 * ubifs_prepare_node - prepare node to be written to flash.
216 * @c: UBIFS file-system description object
217 * @node: the node to pad
218 * @len: node length
219 * @pad: if the buffer has to be padded
220 *
221 * This function prepares node at @node to be written to the media - it
222 * calculates node CRC, fills the common header, and adds proper padding up to
223 * the next minimum I/O unit if @pad is not zero.
224 */
225void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
226{
227 uint32_t crc;
228 struct ubifs_ch *ch = node;
229 unsigned long long sqnum = next_sqnum(c);
230
231 ubifs_assert(len >= UBIFS_CH_SZ);
232
233 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
234 ch->len = cpu_to_le32(len);
235 ch->group_type = UBIFS_NO_NODE_GROUP;
236 ch->sqnum = cpu_to_le64(sqnum);
237 ch->padding[0] = ch->padding[1] = 0;
238 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
239 ch->crc = cpu_to_le32(crc);
240
241 if (pad) {
242 len = ALIGN(len, 8);
243 pad = ALIGN(len, c->min_io_size) - len;
244 ubifs_pad(c, node + len, pad);
245 }
246}
247
248/**
249 * ubifs_prep_grp_node - prepare node of a group to be written to flash.
250 * @c: UBIFS file-system description object
251 * @node: the node to pad
252 * @len: node length
253 * @last: indicates the last node of the group
254 *
255 * This function prepares node at @node to be written to the media - it
256 * calculates node CRC and fills the common header.
257 */
258void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last)
259{
260 uint32_t crc;
261 struct ubifs_ch *ch = node;
262 unsigned long long sqnum = next_sqnum(c);
263
264 ubifs_assert(len >= UBIFS_CH_SZ);
265
266 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
267 ch->len = cpu_to_le32(len);
268 if (last)
269 ch->group_type = UBIFS_LAST_OF_NODE_GROUP;
270 else
271 ch->group_type = UBIFS_IN_NODE_GROUP;
272 ch->sqnum = cpu_to_le64(sqnum);
273 ch->padding[0] = ch->padding[1] = 0;
274 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
275 ch->crc = cpu_to_le32(crc);
276}
277
278/**
279 * wbuf_timer_callback - write-buffer timer callback function.
280 * @data: timer data (write-buffer descriptor)
281 *
282 * This function is called when the write-buffer timer expires.
283 */
284static void wbuf_timer_callback_nolock(unsigned long data)
285{
286 struct ubifs_wbuf *wbuf = (struct ubifs_wbuf *)data;
287
288 wbuf->need_sync = 1;
289 wbuf->c->need_wbuf_sync = 1;
290 ubifs_wake_up_bgt(wbuf->c);
291}
292
293/**
294 * new_wbuf_timer - start new write-buffer timer.
295 * @wbuf: write-buffer descriptor
296 */
297static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
298{
299 ubifs_assert(!timer_pending(&wbuf->timer));
300
301 if (!wbuf->timeout)
302 return;
303
304 wbuf->timer.expires = jiffies + wbuf->timeout;
305 add_timer(&wbuf->timer);
306}
307
308/**
309 * cancel_wbuf_timer - cancel write-buffer timer.
310 * @wbuf: write-buffer descriptor
311 */
312static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
313{
314 /*
315 * If the syncer is waiting for the lock (from the background thread's
316 * context) and another task is changing write-buffer then the syncing
317 * should be canceled.
318 */
319 wbuf->need_sync = 0;
320 del_timer(&wbuf->timer);
321}
322
323/**
324 * ubifs_wbuf_sync_nolock - synchronize write-buffer.
325 * @wbuf: write-buffer to synchronize
326 *
327 * This function synchronizes write-buffer @buf and returns zero in case of
328 * success or a negative error code in case of failure.
329 */
330int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)
331{
332 struct ubifs_info *c = wbuf->c;
333 int err, dirt;
334
335 cancel_wbuf_timer_nolock(wbuf);
336 if (!wbuf->used || wbuf->lnum == -1)
337 /* Write-buffer is empty or not seeked */
338 return 0;
339
340 dbg_io("LEB %d:%d, %d bytes",
341 wbuf->lnum, wbuf->offs, wbuf->used);
342 ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY));
343 ubifs_assert(!(wbuf->avail & 7));
344 ubifs_assert(wbuf->offs + c->min_io_size <= c->leb_size);
345
346 if (c->ro_media)
347 return -EROFS;
348
349 ubifs_pad(c, wbuf->buf + wbuf->used, wbuf->avail);
350 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs,
351 c->min_io_size, wbuf->dtype);
352 if (err) {
353 ubifs_err("cannot write %d bytes to LEB %d:%d",
354 c->min_io_size, wbuf->lnum, wbuf->offs);
355 dbg_dump_stack();
356 return err;
357 }
358
359 dirt = wbuf->avail;
360
361 spin_lock(&wbuf->lock);
362 wbuf->offs += c->min_io_size;
363 wbuf->avail = c->min_io_size;
364 wbuf->used = 0;
365 wbuf->next_ino = 0;
366 spin_unlock(&wbuf->lock);
367
368 if (wbuf->sync_callback)
369 err = wbuf->sync_callback(c, wbuf->lnum,
370 c->leb_size - wbuf->offs, dirt);
371 return err;
372}
373
374/**
375 * ubifs_wbuf_seek_nolock - seek write-buffer.
376 * @wbuf: write-buffer
377 * @lnum: logical eraseblock number to seek to
378 * @offs: logical eraseblock offset to seek to
379 * @dtype: data type
380 *
381 * This function targets the write buffer to logical eraseblock @lnum:@offs.
382 * The write-buffer is synchronized if it is not empty. Returns zero in case of
383 * success and a negative error code in case of failure.
384 */
385int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs,
386 int dtype)
387{
388 const struct ubifs_info *c = wbuf->c;
389
390 dbg_io("LEB %d:%d", lnum, offs);
391 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt);
392 ubifs_assert(offs >= 0 && offs <= c->leb_size);
393 ubifs_assert(offs % c->min_io_size == 0 && !(offs & 7));
394 ubifs_assert(lnum != wbuf->lnum);
395
396 if (wbuf->used > 0) {
397 int err = ubifs_wbuf_sync_nolock(wbuf);
398
399 if (err)
400 return err;
401 }
402
403 spin_lock(&wbuf->lock);
404 wbuf->lnum = lnum;
405 wbuf->offs = offs;
406 wbuf->avail = c->min_io_size;
407 wbuf->used = 0;
408 spin_unlock(&wbuf->lock);
409 wbuf->dtype = dtype;
410
411 return 0;
412}
413
414/**
415 * ubifs_bg_wbufs_sync - synchronize write-buffers.
416 * @c: UBIFS file-system description object
417 *
418 * This function is called by background thread to synchronize write-buffers.
419 * Returns zero in case of success and a negative error code in case of
420 * failure.
421 */
422int ubifs_bg_wbufs_sync(struct ubifs_info *c)
423{
424 int err, i;
425
426 if (!c->need_wbuf_sync)
427 return 0;
428 c->need_wbuf_sync = 0;
429
430 if (c->ro_media) {
431 err = -EROFS;
432 goto out_timers;
433 }
434
435 dbg_io("synchronize");
436 for (i = 0; i < c->jhead_cnt; i++) {
437 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
438
439 cond_resched();
440
441 /*
442 * If the mutex is locked then wbuf is being changed, so
443 * synchronization is not necessary.
444 */
445 if (mutex_is_locked(&wbuf->io_mutex))
446 continue;
447
448 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
449 if (!wbuf->need_sync) {
450 mutex_unlock(&wbuf->io_mutex);
451 continue;
452 }
453
454 err = ubifs_wbuf_sync_nolock(wbuf);
455 mutex_unlock(&wbuf->io_mutex);
456 if (err) {
457 ubifs_err("cannot sync write-buffer, error %d", err);
458 ubifs_ro_mode(c, err);
459 goto out_timers;
460 }
461 }
462
463 return 0;
464
465out_timers:
466 /* Cancel all timers to prevent repeated errors */
467 for (i = 0; i < c->jhead_cnt; i++) {
468 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
469
470 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
471 cancel_wbuf_timer_nolock(wbuf);
472 mutex_unlock(&wbuf->io_mutex);
473 }
474 return err;
475}
476
477/**
478 * ubifs_wbuf_write_nolock - write data to flash via write-buffer.
479 * @wbuf: write-buffer
480 * @buf: node to write
481 * @len: node length
482 *
483 * This function writes data to flash via write-buffer @wbuf. This means that
484 * the last piece of the node won't reach the flash media immediately if it
485 * does not take whole minimal I/O unit. Instead, the node will sit in RAM
486 * until the write-buffer is synchronized (e.g., by timer).
487 *
488 * This function returns zero in case of success and a negative error code in
489 * case of failure. If the node cannot be written because there is no more
490 * space in this logical eraseblock, %-ENOSPC is returned.
491 */
492int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
493{
494 struct ubifs_info *c = wbuf->c;
495 int err, written, n, aligned_len = ALIGN(len, 8), offs;
496
497 dbg_io("%d bytes (%s) to wbuf at LEB %d:%d", len,
498 dbg_ntype(((struct ubifs_ch *)buf)->node_type), wbuf->lnum,
499 wbuf->offs + wbuf->used);
500 ubifs_assert(len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);
501 ubifs_assert(wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);
502 ubifs_assert(!(wbuf->offs & 7) && wbuf->offs <= c->leb_size);
503 ubifs_assert(wbuf->avail > 0 && wbuf->avail <= c->min_io_size);
504 ubifs_assert(mutex_is_locked(&wbuf->io_mutex));
505
506 if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {
507 err = -ENOSPC;
508 goto out;
509 }
510
511 cancel_wbuf_timer_nolock(wbuf);
512
513 if (c->ro_media)
514 return -EROFS;
515
516 if (aligned_len <= wbuf->avail) {
517 /*
518 * The node is not very large and fits entirely within
519 * write-buffer.
520 */
521 memcpy(wbuf->buf + wbuf->used, buf, len);
522
523 if (aligned_len == wbuf->avail) {
524 dbg_io("flush wbuf to LEB %d:%d", wbuf->lnum,
525 wbuf->offs);
526 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf,
527 wbuf->offs, c->min_io_size,
528 wbuf->dtype);
529 if (err)
530 goto out;
531
532 spin_lock(&wbuf->lock);
533 wbuf->offs += c->min_io_size;
534 wbuf->avail = c->min_io_size;
535 wbuf->used = 0;
536 wbuf->next_ino = 0;
537 spin_unlock(&wbuf->lock);
538 } else {
539 spin_lock(&wbuf->lock);
540 wbuf->avail -= aligned_len;
541 wbuf->used += aligned_len;
542 spin_unlock(&wbuf->lock);
543 }
544
545 goto exit;
546 }
547
548 /*
549 * The node is large enough and does not fit entirely within current
550 * minimal I/O unit. We have to fill and flush write-buffer and switch
551 * to the next min. I/O unit.
552 */
553 dbg_io("flush wbuf to LEB %d:%d", wbuf->lnum, wbuf->offs);
554 memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);
555 err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs,
556 c->min_io_size, wbuf->dtype);
557 if (err)
558 goto out;
559
560 offs = wbuf->offs + c->min_io_size;
561 len -= wbuf->avail;
562 aligned_len -= wbuf->avail;
563 written = wbuf->avail;
564
565 /*
566 * The remaining data may take more whole min. I/O units, so write the
567 * remains multiple to min. I/O unit size directly to the flash media.
568 * We align node length to 8-byte boundary because we anyway flash wbuf
569 * if the remaining space is less than 8 bytes.
570 */
571 n = aligned_len >> c->min_io_shift;
572 if (n) {
573 n <<= c->min_io_shift;
574 dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, offs);
575 err = ubi_leb_write(c->ubi, wbuf->lnum, buf + written, offs, n,
576 wbuf->dtype);
577 if (err)
578 goto out;
579 offs += n;
580 aligned_len -= n;
581 len -= n;
582 written += n;
583 }
584
585 spin_lock(&wbuf->lock);
586 if (aligned_len)
587 /*
588 * And now we have what's left and what does not take whole
589 * min. I/O unit, so write it to the write-buffer and we are
590 * done.
591 */
592 memcpy(wbuf->buf, buf + written, len);
593
594 wbuf->offs = offs;
595 wbuf->used = aligned_len;
596 wbuf->avail = c->min_io_size - aligned_len;
597 wbuf->next_ino = 0;
598 spin_unlock(&wbuf->lock);
599
600exit:
601 if (wbuf->sync_callback) {
602 int free = c->leb_size - wbuf->offs - wbuf->used;
603
604 err = wbuf->sync_callback(c, wbuf->lnum, free, 0);
605 if (err)
606 goto out;
607 }
608
609 if (wbuf->used)
610 new_wbuf_timer_nolock(wbuf);
611
612 return 0;
613
614out:
615 ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
616 len, wbuf->lnum, wbuf->offs, err);
617 dbg_dump_node(c, buf);
618 dbg_dump_stack();
619 dbg_dump_leb(c, wbuf->lnum);
620 return err;
621}
622
623/**
624 * ubifs_write_node - write node to the media.
625 * @c: UBIFS file-system description object
626 * @buf: the node to write
627 * @len: node length
628 * @lnum: logical eraseblock number
629 * @offs: offset within the logical eraseblock
630 * @dtype: node life-time hint (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
631 *
632 * This function automatically fills node magic number, assigns sequence
633 * number, and calculates node CRC checksum. The length of the @buf buffer has
634 * to be aligned to the minimal I/O unit size. This function automatically
635 * appends padding node and padding bytes if needed. Returns zero in case of
636 * success and a negative error code in case of failure.
637 */
638int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
639 int offs, int dtype)
640{
641 int err, buf_len = ALIGN(len, c->min_io_size);
642
643 dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
644 lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
645 buf_len);
646 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
647 ubifs_assert(offs % c->min_io_size == 0 && offs < c->leb_size);
648
649 if (c->ro_media)
650 return -EROFS;
651
652 ubifs_prepare_node(c, buf, len, 1);
653 err = ubi_leb_write(c->ubi, lnum, buf, offs, buf_len, dtype);
654 if (err) {
655 ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
656 buf_len, lnum, offs, err);
657 dbg_dump_node(c, buf);
658 dbg_dump_stack();
659 }
660
661 return err;
662}
663
664/**
665 * ubifs_read_node_wbuf - read node from the media or write-buffer.
666 * @wbuf: wbuf to check for un-written data
667 * @buf: buffer to read to
668 * @type: node type
669 * @len: node length
670 * @lnum: logical eraseblock number
671 * @offs: offset within the logical eraseblock
672 *
673 * This function reads a node of known type and length, checks it and stores
674 * in @buf. If the node partially or fully sits in the write-buffer, this
675 * function takes data from the buffer, otherwise it reads the flash media.
676 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
677 * error code in case of failure.
678 */
679int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
680 int lnum, int offs)
681{
682 const struct ubifs_info *c = wbuf->c;
683 int err, rlen, overlap;
684 struct ubifs_ch *ch = buf;
685
686 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
687 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
688 ubifs_assert(!(offs & 7) && offs < c->leb_size);
689 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
690
691 spin_lock(&wbuf->lock);
692 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
693 if (!overlap) {
694 /* We may safely unlock the write-buffer and read the data */
695 spin_unlock(&wbuf->lock);
696 return ubifs_read_node(c, buf, type, len, lnum, offs);
697 }
698
699 /* Don't read under wbuf */
700 rlen = wbuf->offs - offs;
701 if (rlen < 0)
702 rlen = 0;
703
704 /* Copy the rest from the write-buffer */
705 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
706 spin_unlock(&wbuf->lock);
707
708 if (rlen > 0) {
709 /* Read everything that goes before write-buffer */
710 err = ubi_read(c->ubi, lnum, buf, offs, rlen);
711 if (err && err != -EBADMSG) {
712 ubifs_err("failed to read node %d from LEB %d:%d, "
713 "error %d", type, lnum, offs, err);
714 dbg_dump_stack();
715 return err;
716 }
717 }
718
719 if (type != ch->node_type) {
720 ubifs_err("bad node type (%d but expected %d)",
721 ch->node_type, type);
722 goto out;
723 }
724
725 err = ubifs_check_node(c, buf, lnum, offs, 0);
726 if (err) {
727 ubifs_err("expected node type %d", type);
728 return err;
729 }
730
731 rlen = le32_to_cpu(ch->len);
732 if (rlen != len) {
733 ubifs_err("bad node length %d, expected %d", rlen, len);
734 goto out;
735 }
736
737 return 0;
738
739out:
740 ubifs_err("bad node at LEB %d:%d", lnum, offs);
741 dbg_dump_node(c, buf);
742 dbg_dump_stack();
743 return -EINVAL;
744}
745
746/**
747 * ubifs_read_node - read node.
748 * @c: UBIFS file-system description object
749 * @buf: buffer to read to
750 * @type: node type
751 * @len: node length (not aligned)
752 * @lnum: logical eraseblock number
753 * @offs: offset within the logical eraseblock
754 *
755 * This function reads a node of known type and and length, checks it and
756 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
757 * and a negative error code in case of failure.
758 */
759int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
760 int lnum, int offs)
761{
762 int err, l;
763 struct ubifs_ch *ch = buf;
764
765 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
766 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
767 ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
768 ubifs_assert(!(offs & 7) && offs < c->leb_size);
769 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
770
771 err = ubi_read(c->ubi, lnum, buf, offs, len);
772 if (err && err != -EBADMSG) {
773 ubifs_err("cannot read node %d from LEB %d:%d, error %d",
774 type, lnum, offs, err);
775 return err;
776 }
777
778 if (type != ch->node_type) {
779 ubifs_err("bad node type (%d but expected %d)",
780 ch->node_type, type);
781 goto out;
782 }
783
784 err = ubifs_check_node(c, buf, lnum, offs, 0);
785 if (err) {
786 ubifs_err("expected node type %d", type);
787 return err;
788 }
789
790 l = le32_to_cpu(ch->len);
791 if (l != len) {
792 ubifs_err("bad node length %d, expected %d", l, len);
793 goto out;
794 }
795
796 return 0;
797
798out:
799 ubifs_err("bad node at LEB %d:%d", lnum, offs);
800 dbg_dump_node(c, buf);
801 dbg_dump_stack();
802 return -EINVAL;
803}
804
805/**
806 * ubifs_wbuf_init - initialize write-buffer.
807 * @c: UBIFS file-system description object
808 * @wbuf: write-buffer to initialize
809 *
810 * This function initializes write buffer. Returns zero in case of success
811 * %-ENOMEM in case of failure.
812 */
813int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
814{
815 size_t size;
816
817 wbuf->buf = kmalloc(c->min_io_size, GFP_KERNEL);
818 if (!wbuf->buf)
819 return -ENOMEM;
820
821 size = (c->min_io_size / UBIFS_CH_SZ + 1) * sizeof(ino_t);
822 wbuf->inodes = kmalloc(size, GFP_KERNEL);
823 if (!wbuf->inodes) {
824 kfree(wbuf->buf);
825 wbuf->buf = NULL;
826 return -ENOMEM;
827 }
828
829 wbuf->used = 0;
830 wbuf->lnum = wbuf->offs = -1;
831 wbuf->avail = c->min_io_size;
832 wbuf->dtype = UBI_UNKNOWN;
833 wbuf->sync_callback = NULL;
834 mutex_init(&wbuf->io_mutex);
835 spin_lock_init(&wbuf->lock);
836
837 wbuf->c = c;
838 init_timer(&wbuf->timer);
839 wbuf->timer.function = wbuf_timer_callback_nolock;
840 wbuf->timer.data = (unsigned long)wbuf;
841 wbuf->timeout = DEFAULT_WBUF_TIMEOUT;
842 wbuf->next_ino = 0;
843
844 return 0;
845}
846
847/**
848 * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array.
849 * @wbuf: the write-buffer whereto add
850 * @inum: the inode number
851 *
852 * This function adds an inode number to the inode array of the write-buffer.
853 */
854void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum)
855{
856 if (!wbuf->buf)
857 /* NOR flash or something similar */
858 return;
859
860 spin_lock(&wbuf->lock);
861 if (wbuf->used)
862 wbuf->inodes[wbuf->next_ino++] = inum;
863 spin_unlock(&wbuf->lock);
864}
865
866/**
867 * wbuf_has_ino - returns if the wbuf contains data from the inode.
868 * @wbuf: the write-buffer
869 * @inum: the inode number
870 *
871 * This function returns with %1 if the write-buffer contains some data from the
872 * given inode otherwise it returns with %0.
873 */
874static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum)
875{
876 int i, ret = 0;
877
878 spin_lock(&wbuf->lock);
879 for (i = 0; i < wbuf->next_ino; i++)
880 if (inum == wbuf->inodes[i]) {
881 ret = 1;
882 break;
883 }
884 spin_unlock(&wbuf->lock);
885
886 return ret;
887}
888
889/**
890 * ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode.
891 * @c: UBIFS file-system description object
892 * @inode: inode to synchronize
893 *
894 * This function synchronizes write-buffers which contain nodes belonging to
895 * @inode. Returns zero in case of success and a negative error code in case of
896 * failure.
897 */
898int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)
899{
900 int i, err = 0;
901
902 for (i = 0; i < c->jhead_cnt; i++) {
903 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
904
905 if (i == GCHD)
906 /*
907 * GC head is special, do not look at it. Even if the
908 * head contains something related to this inode, it is
909 * a _copy_ of corresponding on-flash node which sits
910 * somewhere else.
911 */
912 continue;
913
914 if (!wbuf_has_ino(wbuf, inode->i_ino))
915 continue;
916
917 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
918 if (wbuf_has_ino(wbuf, inode->i_ino))
919 err = ubifs_wbuf_sync_nolock(wbuf);
920 mutex_unlock(&wbuf->io_mutex);
921
922 if (err) {
923 ubifs_ro_mode(c, err);
924 return err;
925 }
926 }
927 return 0;
928}