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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}
1/*
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 * similar to the mechanism is used by JFFS2.
33 *
34 * UBIFS distinguishes between minimum write size (@c->min_io_size) and maximum
35 * write size (@c->max_write_size). The latter is the maximum amount of bytes
36 * the underlying flash is able to program at a time, and writing in
37 * @c->max_write_size units should presumably be faster. Obviously,
38 * @c->min_io_size <= @c->max_write_size. Write-buffers are of
39 * @c->max_write_size bytes in size for maximum performance. However, when a
40 * write-buffer is flushed, only the portion of it (aligned to @c->min_io_size
41 * boundary) which contains data is written, not the whole write-buffer,
42 * because this is more space-efficient.
43 *
44 * This optimization adds few complications to the code. Indeed, on the one
45 * hand, we want to write in optimal @c->max_write_size bytes chunks, which
46 * also means aligning writes at the @c->max_write_size bytes offsets. On the
47 * other hand, we do not want to waste space when synchronizing the write
48 * buffer, so during synchronization we writes in smaller chunks. And this makes
49 * the next write offset to be not aligned to @c->max_write_size bytes. So the
50 * have to make sure that the write-buffer offset (@wbuf->offs) becomes aligned
51 * to @c->max_write_size bytes again. We do this by temporarily shrinking
52 * write-buffer size (@wbuf->size).
53 *
54 * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by
55 * mutexes defined inside these objects. Since sometimes upper-level code
56 * has to lock the write-buffer (e.g. journal space reservation code), many
57 * functions related to write-buffers have "nolock" suffix which means that the
58 * caller has to lock the write-buffer before calling this function.
59 *
60 * UBIFS stores nodes at 64 bit-aligned addresses. If the node length is not
61 * aligned, UBIFS starts the next node from the aligned address, and the padded
62 * bytes may contain any rubbish. In other words, UBIFS does not put padding
63 * bytes in those small gaps. Common headers of nodes store real node lengths,
64 * not aligned lengths. Indexing nodes also store real lengths in branches.
65 *
66 * UBIFS uses padding when it pads to the next min. I/O unit. In this case it
67 * uses padding nodes or padding bytes, if the padding node does not fit.
68 *
69 * All UBIFS nodes are protected by CRC checksums and UBIFS checks CRC when
70 * they are read from the flash media.
71 */
72
73#include <linux/crc32.h>
74#include <linux/slab.h>
75#include "ubifs.h"
76
77/**
78 * ubifs_ro_mode - switch UBIFS to read read-only mode.
79 * @c: UBIFS file-system description object
80 * @err: error code which is the reason of switching to R/O mode
81 */
82void ubifs_ro_mode(struct ubifs_info *c, int err)
83{
84 if (!c->ro_error) {
85 c->ro_error = 1;
86 c->no_chk_data_crc = 0;
87 c->vfs_sb->s_flags |= SB_RDONLY;
88 ubifs_warn(c, "switched to read-only mode, error %d", err);
89 dump_stack();
90 }
91}
92
93/*
94 * Below are simple wrappers over UBI I/O functions which include some
95 * additional checks and UBIFS debugging stuff. See corresponding UBI function
96 * for more information.
97 */
98
99int ubifs_leb_read(const struct ubifs_info *c, int lnum, void *buf, int offs,
100 int len, int even_ebadmsg)
101{
102 int err;
103
104 err = ubi_read(c->ubi, lnum, buf, offs, len);
105 /*
106 * In case of %-EBADMSG print the error message only if the
107 * @even_ebadmsg is true.
108 */
109 if (err && (err != -EBADMSG || even_ebadmsg)) {
110 ubifs_err(c, "reading %d bytes from LEB %d:%d failed, error %d",
111 len, lnum, offs, err);
112 dump_stack();
113 }
114 return err;
115}
116
117int ubifs_leb_write(struct ubifs_info *c, int lnum, const void *buf, int offs,
118 int len)
119{
120 int err;
121
122 ubifs_assert(!c->ro_media && !c->ro_mount);
123 if (c->ro_error)
124 return -EROFS;
125 if (!dbg_is_tst_rcvry(c))
126 err = ubi_leb_write(c->ubi, lnum, buf, offs, len);
127 else
128 err = dbg_leb_write(c, lnum, buf, offs, len);
129 if (err) {
130 ubifs_err(c, "writing %d bytes to LEB %d:%d failed, error %d",
131 len, lnum, offs, err);
132 ubifs_ro_mode(c, err);
133 dump_stack();
134 }
135 return err;
136}
137
138int ubifs_leb_change(struct ubifs_info *c, int lnum, const void *buf, int len)
139{
140 int err;
141
142 ubifs_assert(!c->ro_media && !c->ro_mount);
143 if (c->ro_error)
144 return -EROFS;
145 if (!dbg_is_tst_rcvry(c))
146 err = ubi_leb_change(c->ubi, lnum, buf, len);
147 else
148 err = dbg_leb_change(c, lnum, buf, len);
149 if (err) {
150 ubifs_err(c, "changing %d bytes in LEB %d failed, error %d",
151 len, lnum, err);
152 ubifs_ro_mode(c, err);
153 dump_stack();
154 }
155 return err;
156}
157
158int ubifs_leb_unmap(struct ubifs_info *c, int lnum)
159{
160 int err;
161
162 ubifs_assert(!c->ro_media && !c->ro_mount);
163 if (c->ro_error)
164 return -EROFS;
165 if (!dbg_is_tst_rcvry(c))
166 err = ubi_leb_unmap(c->ubi, lnum);
167 else
168 err = dbg_leb_unmap(c, lnum);
169 if (err) {
170 ubifs_err(c, "unmap LEB %d failed, error %d", lnum, err);
171 ubifs_ro_mode(c, err);
172 dump_stack();
173 }
174 return err;
175}
176
177int ubifs_leb_map(struct ubifs_info *c, int lnum)
178{
179 int err;
180
181 ubifs_assert(!c->ro_media && !c->ro_mount);
182 if (c->ro_error)
183 return -EROFS;
184 if (!dbg_is_tst_rcvry(c))
185 err = ubi_leb_map(c->ubi, lnum);
186 else
187 err = dbg_leb_map(c, lnum);
188 if (err) {
189 ubifs_err(c, "mapping LEB %d failed, error %d", lnum, err);
190 ubifs_ro_mode(c, err);
191 dump_stack();
192 }
193 return err;
194}
195
196int ubifs_is_mapped(const struct ubifs_info *c, int lnum)
197{
198 int err;
199
200 err = ubi_is_mapped(c->ubi, lnum);
201 if (err < 0) {
202 ubifs_err(c, "ubi_is_mapped failed for LEB %d, error %d",
203 lnum, err);
204 dump_stack();
205 }
206 return err;
207}
208
209/**
210 * ubifs_check_node - check node.
211 * @c: UBIFS file-system description object
212 * @buf: node to check
213 * @lnum: logical eraseblock number
214 * @offs: offset within the logical eraseblock
215 * @quiet: print no messages
216 * @must_chk_crc: indicates whether to always check the CRC
217 *
218 * This function checks node magic number and CRC checksum. This function also
219 * validates node length to prevent UBIFS from becoming crazy when an attacker
220 * feeds it a file-system image with incorrect nodes. For example, too large
221 * node length in the common header could cause UBIFS to read memory outside of
222 * allocated buffer when checking the CRC checksum.
223 *
224 * This function may skip data nodes CRC checking if @c->no_chk_data_crc is
225 * true, which is controlled by corresponding UBIFS mount option. However, if
226 * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
227 * checked. Similarly, if @c->mounting or @c->remounting_rw is true (we are
228 * mounting or re-mounting to R/W mode), @c->no_chk_data_crc is ignored and CRC
229 * is checked. This is because during mounting or re-mounting from R/O mode to
230 * R/W mode we may read journal nodes (when replying the journal or doing the
231 * recovery) and the journal nodes may potentially be corrupted, so checking is
232 * required.
233 *
234 * This function returns zero in case of success and %-EUCLEAN in case of bad
235 * CRC or magic.
236 */
237int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
238 int offs, int quiet, int must_chk_crc)
239{
240 int err = -EINVAL, type, node_len;
241 uint32_t crc, node_crc, magic;
242 const struct ubifs_ch *ch = buf;
243
244 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
245 ubifs_assert(!(offs & 7) && offs < c->leb_size);
246
247 magic = le32_to_cpu(ch->magic);
248 if (magic != UBIFS_NODE_MAGIC) {
249 if (!quiet)
250 ubifs_err(c, "bad magic %#08x, expected %#08x",
251 magic, UBIFS_NODE_MAGIC);
252 err = -EUCLEAN;
253 goto out;
254 }
255
256 type = ch->node_type;
257 if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
258 if (!quiet)
259 ubifs_err(c, "bad node type %d", type);
260 goto out;
261 }
262
263 node_len = le32_to_cpu(ch->len);
264 if (node_len + offs > c->leb_size)
265 goto out_len;
266
267 if (c->ranges[type].max_len == 0) {
268 if (node_len != c->ranges[type].len)
269 goto out_len;
270 } else if (node_len < c->ranges[type].min_len ||
271 node_len > c->ranges[type].max_len)
272 goto out_len;
273
274 if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->mounting &&
275 !c->remounting_rw && c->no_chk_data_crc)
276 return 0;
277
278 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
279 node_crc = le32_to_cpu(ch->crc);
280 if (crc != node_crc) {
281 if (!quiet)
282 ubifs_err(c, "bad CRC: calculated %#08x, read %#08x",
283 crc, node_crc);
284 err = -EUCLEAN;
285 goto out;
286 }
287
288 return 0;
289
290out_len:
291 if (!quiet)
292 ubifs_err(c, "bad node length %d", node_len);
293out:
294 if (!quiet) {
295 ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);
296 ubifs_dump_node(c, buf);
297 dump_stack();
298 }
299 return err;
300}
301
302/**
303 * ubifs_pad - pad flash space.
304 * @c: UBIFS file-system description object
305 * @buf: buffer to put padding to
306 * @pad: how many bytes to pad
307 *
308 * The flash media obliges us to write only in chunks of %c->min_io_size and
309 * when we have to write less data we add padding node to the write-buffer and
310 * pad it to the next minimal I/O unit's boundary. Padding nodes help when the
311 * media is being scanned. If the amount of wasted space is not enough to fit a
312 * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes
313 * pattern (%UBIFS_PADDING_BYTE).
314 *
315 * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is
316 * used.
317 */
318void ubifs_pad(const struct ubifs_info *c, void *buf, int pad)
319{
320 uint32_t crc;
321
322 ubifs_assert(pad >= 0 && !(pad & 7));
323
324 if (pad >= UBIFS_PAD_NODE_SZ) {
325 struct ubifs_ch *ch = buf;
326 struct ubifs_pad_node *pad_node = buf;
327
328 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
329 ch->node_type = UBIFS_PAD_NODE;
330 ch->group_type = UBIFS_NO_NODE_GROUP;
331 ch->padding[0] = ch->padding[1] = 0;
332 ch->sqnum = 0;
333 ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ);
334 pad -= UBIFS_PAD_NODE_SZ;
335 pad_node->pad_len = cpu_to_le32(pad);
336 crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8);
337 ch->crc = cpu_to_le32(crc);
338 memset(buf + UBIFS_PAD_NODE_SZ, 0, pad);
339 } else if (pad > 0)
340 /* Too little space, padding node won't fit */
341 memset(buf, UBIFS_PADDING_BYTE, pad);
342}
343
344/**
345 * next_sqnum - get next sequence number.
346 * @c: UBIFS file-system description object
347 */
348static unsigned long long next_sqnum(struct ubifs_info *c)
349{
350 unsigned long long sqnum;
351
352 spin_lock(&c->cnt_lock);
353 sqnum = ++c->max_sqnum;
354 spin_unlock(&c->cnt_lock);
355
356 if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) {
357 if (sqnum >= SQNUM_WATERMARK) {
358 ubifs_err(c, "sequence number overflow %llu, end of life",
359 sqnum);
360 ubifs_ro_mode(c, -EINVAL);
361 }
362 ubifs_warn(c, "running out of sequence numbers, end of life soon");
363 }
364
365 return sqnum;
366}
367
368/**
369 * ubifs_prepare_node - prepare node to be written to flash.
370 * @c: UBIFS file-system description object
371 * @node: the node to pad
372 * @len: node length
373 * @pad: if the buffer has to be padded
374 *
375 * This function prepares node at @node to be written to the media - it
376 * calculates node CRC, fills the common header, and adds proper padding up to
377 * the next minimum I/O unit if @pad is not zero.
378 */
379void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
380{
381 uint32_t crc;
382 struct ubifs_ch *ch = node;
383 unsigned long long sqnum = next_sqnum(c);
384
385 ubifs_assert(len >= UBIFS_CH_SZ);
386
387 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
388 ch->len = cpu_to_le32(len);
389 ch->group_type = UBIFS_NO_NODE_GROUP;
390 ch->sqnum = cpu_to_le64(sqnum);
391 ch->padding[0] = ch->padding[1] = 0;
392 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
393 ch->crc = cpu_to_le32(crc);
394
395 if (pad) {
396 len = ALIGN(len, 8);
397 pad = ALIGN(len, c->min_io_size) - len;
398 ubifs_pad(c, node + len, pad);
399 }
400}
401
402/**
403 * ubifs_prep_grp_node - prepare node of a group to be written to flash.
404 * @c: UBIFS file-system description object
405 * @node: the node to pad
406 * @len: node length
407 * @last: indicates the last node of the group
408 *
409 * This function prepares node at @node to be written to the media - it
410 * calculates node CRC and fills the common header.
411 */
412void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last)
413{
414 uint32_t crc;
415 struct ubifs_ch *ch = node;
416 unsigned long long sqnum = next_sqnum(c);
417
418 ubifs_assert(len >= UBIFS_CH_SZ);
419
420 ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
421 ch->len = cpu_to_le32(len);
422 if (last)
423 ch->group_type = UBIFS_LAST_OF_NODE_GROUP;
424 else
425 ch->group_type = UBIFS_IN_NODE_GROUP;
426 ch->sqnum = cpu_to_le64(sqnum);
427 ch->padding[0] = ch->padding[1] = 0;
428 crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
429 ch->crc = cpu_to_le32(crc);
430}
431
432/**
433 * wbuf_timer_callback - write-buffer timer callback function.
434 * @timer: timer data (write-buffer descriptor)
435 *
436 * This function is called when the write-buffer timer expires.
437 */
438static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer)
439{
440 struct ubifs_wbuf *wbuf = container_of(timer, struct ubifs_wbuf, timer);
441
442 dbg_io("jhead %s", dbg_jhead(wbuf->jhead));
443 wbuf->need_sync = 1;
444 wbuf->c->need_wbuf_sync = 1;
445 ubifs_wake_up_bgt(wbuf->c);
446 return HRTIMER_NORESTART;
447}
448
449/**
450 * new_wbuf_timer - start new write-buffer timer.
451 * @wbuf: write-buffer descriptor
452 */
453static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
454{
455 ktime_t softlimit = ms_to_ktime(dirty_writeback_interval * 10);
456 unsigned long long delta = dirty_writeback_interval;
457
458 /* centi to milli, milli to nano, then 10% */
459 delta *= 10ULL * NSEC_PER_MSEC / 10ULL;
460
461 ubifs_assert(!hrtimer_active(&wbuf->timer));
462 ubifs_assert(delta <= ULONG_MAX);
463
464 if (wbuf->no_timer)
465 return;
466 dbg_io("set timer for jhead %s, %llu-%llu millisecs",
467 dbg_jhead(wbuf->jhead),
468 div_u64(ktime_to_ns(softlimit), USEC_PER_SEC),
469 div_u64(ktime_to_ns(softlimit) + delta, USEC_PER_SEC));
470 hrtimer_start_range_ns(&wbuf->timer, softlimit, delta,
471 HRTIMER_MODE_REL);
472}
473
474/**
475 * cancel_wbuf_timer - cancel write-buffer timer.
476 * @wbuf: write-buffer descriptor
477 */
478static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
479{
480 if (wbuf->no_timer)
481 return;
482 wbuf->need_sync = 0;
483 hrtimer_cancel(&wbuf->timer);
484}
485
486/**
487 * ubifs_wbuf_sync_nolock - synchronize write-buffer.
488 * @wbuf: write-buffer to synchronize
489 *
490 * This function synchronizes write-buffer @buf and returns zero in case of
491 * success or a negative error code in case of failure.
492 *
493 * Note, although write-buffers are of @c->max_write_size, this function does
494 * not necessarily writes all @c->max_write_size bytes to the flash. Instead,
495 * if the write-buffer is only partially filled with data, only the used part
496 * of the write-buffer (aligned on @c->min_io_size boundary) is synchronized.
497 * This way we waste less space.
498 */
499int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)
500{
501 struct ubifs_info *c = wbuf->c;
502 int err, dirt, sync_len;
503
504 cancel_wbuf_timer_nolock(wbuf);
505 if (!wbuf->used || wbuf->lnum == -1)
506 /* Write-buffer is empty or not seeked */
507 return 0;
508
509 dbg_io("LEB %d:%d, %d bytes, jhead %s",
510 wbuf->lnum, wbuf->offs, wbuf->used, dbg_jhead(wbuf->jhead));
511 ubifs_assert(!(wbuf->avail & 7));
512 ubifs_assert(wbuf->offs + wbuf->size <= c->leb_size);
513 ubifs_assert(wbuf->size >= c->min_io_size);
514 ubifs_assert(wbuf->size <= c->max_write_size);
515 ubifs_assert(wbuf->size % c->min_io_size == 0);
516 ubifs_assert(!c->ro_media && !c->ro_mount);
517 if (c->leb_size - wbuf->offs >= c->max_write_size)
518 ubifs_assert(!((wbuf->offs + wbuf->size) % c->max_write_size));
519
520 if (c->ro_error)
521 return -EROFS;
522
523 /*
524 * Do not write whole write buffer but write only the minimum necessary
525 * amount of min. I/O units.
526 */
527 sync_len = ALIGN(wbuf->used, c->min_io_size);
528 dirt = sync_len - wbuf->used;
529 if (dirt)
530 ubifs_pad(c, wbuf->buf + wbuf->used, dirt);
531 err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, sync_len);
532 if (err)
533 return err;
534
535 spin_lock(&wbuf->lock);
536 wbuf->offs += sync_len;
537 /*
538 * Now @wbuf->offs is not necessarily aligned to @c->max_write_size.
539 * But our goal is to optimize writes and make sure we write in
540 * @c->max_write_size chunks and to @c->max_write_size-aligned offset.
541 * Thus, if @wbuf->offs is not aligned to @c->max_write_size now, make
542 * sure that @wbuf->offs + @wbuf->size is aligned to
543 * @c->max_write_size. This way we make sure that after next
544 * write-buffer flush we are again at the optimal offset (aligned to
545 * @c->max_write_size).
546 */
547 if (c->leb_size - wbuf->offs < c->max_write_size)
548 wbuf->size = c->leb_size - wbuf->offs;
549 else if (wbuf->offs & (c->max_write_size - 1))
550 wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs;
551 else
552 wbuf->size = c->max_write_size;
553 wbuf->avail = wbuf->size;
554 wbuf->used = 0;
555 wbuf->next_ino = 0;
556 spin_unlock(&wbuf->lock);
557
558 if (wbuf->sync_callback)
559 err = wbuf->sync_callback(c, wbuf->lnum,
560 c->leb_size - wbuf->offs, dirt);
561 return err;
562}
563
564/**
565 * ubifs_wbuf_seek_nolock - seek write-buffer.
566 * @wbuf: write-buffer
567 * @lnum: logical eraseblock number to seek to
568 * @offs: logical eraseblock offset to seek to
569 *
570 * This function targets the write-buffer to logical eraseblock @lnum:@offs.
571 * The write-buffer has to be empty. Returns zero in case of success and a
572 * negative error code in case of failure.
573 */
574int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs)
575{
576 const struct ubifs_info *c = wbuf->c;
577
578 dbg_io("LEB %d:%d, jhead %s", lnum, offs, dbg_jhead(wbuf->jhead));
579 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt);
580 ubifs_assert(offs >= 0 && offs <= c->leb_size);
581 ubifs_assert(offs % c->min_io_size == 0 && !(offs & 7));
582 ubifs_assert(lnum != wbuf->lnum);
583 ubifs_assert(wbuf->used == 0);
584
585 spin_lock(&wbuf->lock);
586 wbuf->lnum = lnum;
587 wbuf->offs = offs;
588 if (c->leb_size - wbuf->offs < c->max_write_size)
589 wbuf->size = c->leb_size - wbuf->offs;
590 else if (wbuf->offs & (c->max_write_size - 1))
591 wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs;
592 else
593 wbuf->size = c->max_write_size;
594 wbuf->avail = wbuf->size;
595 wbuf->used = 0;
596 spin_unlock(&wbuf->lock);
597
598 return 0;
599}
600
601/**
602 * ubifs_bg_wbufs_sync - synchronize write-buffers.
603 * @c: UBIFS file-system description object
604 *
605 * This function is called by background thread to synchronize write-buffers.
606 * Returns zero in case of success and a negative error code in case of
607 * failure.
608 */
609int ubifs_bg_wbufs_sync(struct ubifs_info *c)
610{
611 int err, i;
612
613 ubifs_assert(!c->ro_media && !c->ro_mount);
614 if (!c->need_wbuf_sync)
615 return 0;
616 c->need_wbuf_sync = 0;
617
618 if (c->ro_error) {
619 err = -EROFS;
620 goto out_timers;
621 }
622
623 dbg_io("synchronize");
624 for (i = 0; i < c->jhead_cnt; i++) {
625 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
626
627 cond_resched();
628
629 /*
630 * If the mutex is locked then wbuf is being changed, so
631 * synchronization is not necessary.
632 */
633 if (mutex_is_locked(&wbuf->io_mutex))
634 continue;
635
636 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
637 if (!wbuf->need_sync) {
638 mutex_unlock(&wbuf->io_mutex);
639 continue;
640 }
641
642 err = ubifs_wbuf_sync_nolock(wbuf);
643 mutex_unlock(&wbuf->io_mutex);
644 if (err) {
645 ubifs_err(c, "cannot sync write-buffer, error %d", err);
646 ubifs_ro_mode(c, err);
647 goto out_timers;
648 }
649 }
650
651 return 0;
652
653out_timers:
654 /* Cancel all timers to prevent repeated errors */
655 for (i = 0; i < c->jhead_cnt; i++) {
656 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
657
658 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
659 cancel_wbuf_timer_nolock(wbuf);
660 mutex_unlock(&wbuf->io_mutex);
661 }
662 return err;
663}
664
665/**
666 * ubifs_wbuf_write_nolock - write data to flash via write-buffer.
667 * @wbuf: write-buffer
668 * @buf: node to write
669 * @len: node length
670 *
671 * This function writes data to flash via write-buffer @wbuf. This means that
672 * the last piece of the node won't reach the flash media immediately if it
673 * does not take whole max. write unit (@c->max_write_size). Instead, the node
674 * will sit in RAM until the write-buffer is synchronized (e.g., by timer, or
675 * because more data are appended to the write-buffer).
676 *
677 * This function returns zero in case of success and a negative error code in
678 * case of failure. If the node cannot be written because there is no more
679 * space in this logical eraseblock, %-ENOSPC is returned.
680 */
681int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
682{
683 struct ubifs_info *c = wbuf->c;
684 int err, written, n, aligned_len = ALIGN(len, 8);
685
686 dbg_io("%d bytes (%s) to jhead %s wbuf at LEB %d:%d", len,
687 dbg_ntype(((struct ubifs_ch *)buf)->node_type),
688 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs + wbuf->used);
689 ubifs_assert(len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);
690 ubifs_assert(wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);
691 ubifs_assert(!(wbuf->offs & 7) && wbuf->offs <= c->leb_size);
692 ubifs_assert(wbuf->avail > 0 && wbuf->avail <= wbuf->size);
693 ubifs_assert(wbuf->size >= c->min_io_size);
694 ubifs_assert(wbuf->size <= c->max_write_size);
695 ubifs_assert(wbuf->size % c->min_io_size == 0);
696 ubifs_assert(mutex_is_locked(&wbuf->io_mutex));
697 ubifs_assert(!c->ro_media && !c->ro_mount);
698 ubifs_assert(!c->space_fixup);
699 if (c->leb_size - wbuf->offs >= c->max_write_size)
700 ubifs_assert(!((wbuf->offs + wbuf->size) % c->max_write_size));
701
702 if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {
703 err = -ENOSPC;
704 goto out;
705 }
706
707 cancel_wbuf_timer_nolock(wbuf);
708
709 if (c->ro_error)
710 return -EROFS;
711
712 if (aligned_len <= wbuf->avail) {
713 /*
714 * The node is not very large and fits entirely within
715 * write-buffer.
716 */
717 memcpy(wbuf->buf + wbuf->used, buf, len);
718
719 if (aligned_len == wbuf->avail) {
720 dbg_io("flush jhead %s wbuf to LEB %d:%d",
721 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
722 err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf,
723 wbuf->offs, wbuf->size);
724 if (err)
725 goto out;
726
727 spin_lock(&wbuf->lock);
728 wbuf->offs += wbuf->size;
729 if (c->leb_size - wbuf->offs >= c->max_write_size)
730 wbuf->size = c->max_write_size;
731 else
732 wbuf->size = c->leb_size - wbuf->offs;
733 wbuf->avail = wbuf->size;
734 wbuf->used = 0;
735 wbuf->next_ino = 0;
736 spin_unlock(&wbuf->lock);
737 } else {
738 spin_lock(&wbuf->lock);
739 wbuf->avail -= aligned_len;
740 wbuf->used += aligned_len;
741 spin_unlock(&wbuf->lock);
742 }
743
744 goto exit;
745 }
746
747 written = 0;
748
749 if (wbuf->used) {
750 /*
751 * The node is large enough and does not fit entirely within
752 * current available space. We have to fill and flush
753 * write-buffer and switch to the next max. write unit.
754 */
755 dbg_io("flush jhead %s wbuf to LEB %d:%d",
756 dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
757 memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);
758 err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs,
759 wbuf->size);
760 if (err)
761 goto out;
762
763 wbuf->offs += wbuf->size;
764 len -= wbuf->avail;
765 aligned_len -= wbuf->avail;
766 written += wbuf->avail;
767 } else if (wbuf->offs & (c->max_write_size - 1)) {
768 /*
769 * The write-buffer offset is not aligned to
770 * @c->max_write_size and @wbuf->size is less than
771 * @c->max_write_size. Write @wbuf->size bytes to make sure the
772 * following writes are done in optimal @c->max_write_size
773 * chunks.
774 */
775 dbg_io("write %d bytes to LEB %d:%d",
776 wbuf->size, wbuf->lnum, wbuf->offs);
777 err = ubifs_leb_write(c, wbuf->lnum, buf, wbuf->offs,
778 wbuf->size);
779 if (err)
780 goto out;
781
782 wbuf->offs += wbuf->size;
783 len -= wbuf->size;
784 aligned_len -= wbuf->size;
785 written += wbuf->size;
786 }
787
788 /*
789 * The remaining data may take more whole max. write units, so write the
790 * remains multiple to max. write unit size directly to the flash media.
791 * We align node length to 8-byte boundary because we anyway flash wbuf
792 * if the remaining space is less than 8 bytes.
793 */
794 n = aligned_len >> c->max_write_shift;
795 if (n) {
796 n <<= c->max_write_shift;
797 dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum,
798 wbuf->offs);
799 err = ubifs_leb_write(c, wbuf->lnum, buf + written,
800 wbuf->offs, n);
801 if (err)
802 goto out;
803 wbuf->offs += n;
804 aligned_len -= n;
805 len -= n;
806 written += n;
807 }
808
809 spin_lock(&wbuf->lock);
810 if (aligned_len)
811 /*
812 * And now we have what's left and what does not take whole
813 * max. write unit, so write it to the write-buffer and we are
814 * done.
815 */
816 memcpy(wbuf->buf, buf + written, len);
817
818 if (c->leb_size - wbuf->offs >= c->max_write_size)
819 wbuf->size = c->max_write_size;
820 else
821 wbuf->size = c->leb_size - wbuf->offs;
822 wbuf->avail = wbuf->size - aligned_len;
823 wbuf->used = aligned_len;
824 wbuf->next_ino = 0;
825 spin_unlock(&wbuf->lock);
826
827exit:
828 if (wbuf->sync_callback) {
829 int free = c->leb_size - wbuf->offs - wbuf->used;
830
831 err = wbuf->sync_callback(c, wbuf->lnum, free, 0);
832 if (err)
833 goto out;
834 }
835
836 if (wbuf->used)
837 new_wbuf_timer_nolock(wbuf);
838
839 return 0;
840
841out:
842 ubifs_err(c, "cannot write %d bytes to LEB %d:%d, error %d",
843 len, wbuf->lnum, wbuf->offs, err);
844 ubifs_dump_node(c, buf);
845 dump_stack();
846 ubifs_dump_leb(c, wbuf->lnum);
847 return err;
848}
849
850/**
851 * ubifs_write_node - write node to the media.
852 * @c: UBIFS file-system description object
853 * @buf: the node to write
854 * @len: node length
855 * @lnum: logical eraseblock number
856 * @offs: offset within the logical eraseblock
857 *
858 * This function automatically fills node magic number, assigns sequence
859 * number, and calculates node CRC checksum. The length of the @buf buffer has
860 * to be aligned to the minimal I/O unit size. This function automatically
861 * appends padding node and padding bytes if needed. Returns zero in case of
862 * success and a negative error code in case of failure.
863 */
864int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
865 int offs)
866{
867 int err, buf_len = ALIGN(len, c->min_io_size);
868
869 dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
870 lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
871 buf_len);
872 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
873 ubifs_assert(offs % c->min_io_size == 0 && offs < c->leb_size);
874 ubifs_assert(!c->ro_media && !c->ro_mount);
875 ubifs_assert(!c->space_fixup);
876
877 if (c->ro_error)
878 return -EROFS;
879
880 ubifs_prepare_node(c, buf, len, 1);
881 err = ubifs_leb_write(c, lnum, buf, offs, buf_len);
882 if (err)
883 ubifs_dump_node(c, buf);
884
885 return err;
886}
887
888/**
889 * ubifs_read_node_wbuf - read node from the media or write-buffer.
890 * @wbuf: wbuf to check for un-written data
891 * @buf: buffer to read to
892 * @type: node type
893 * @len: node length
894 * @lnum: logical eraseblock number
895 * @offs: offset within the logical eraseblock
896 *
897 * This function reads a node of known type and length, checks it and stores
898 * in @buf. If the node partially or fully sits in the write-buffer, this
899 * function takes data from the buffer, otherwise it reads the flash media.
900 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
901 * error code in case of failure.
902 */
903int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
904 int lnum, int offs)
905{
906 const struct ubifs_info *c = wbuf->c;
907 int err, rlen, overlap;
908 struct ubifs_ch *ch = buf;
909
910 dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs,
911 dbg_ntype(type), len, dbg_jhead(wbuf->jhead));
912 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
913 ubifs_assert(!(offs & 7) && offs < c->leb_size);
914 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
915
916 spin_lock(&wbuf->lock);
917 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
918 if (!overlap) {
919 /* We may safely unlock the write-buffer and read the data */
920 spin_unlock(&wbuf->lock);
921 return ubifs_read_node(c, buf, type, len, lnum, offs);
922 }
923
924 /* Don't read under wbuf */
925 rlen = wbuf->offs - offs;
926 if (rlen < 0)
927 rlen = 0;
928
929 /* Copy the rest from the write-buffer */
930 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
931 spin_unlock(&wbuf->lock);
932
933 if (rlen > 0) {
934 /* Read everything that goes before write-buffer */
935 err = ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
936 if (err && err != -EBADMSG)
937 return err;
938 }
939
940 if (type != ch->node_type) {
941 ubifs_err(c, "bad node type (%d but expected %d)",
942 ch->node_type, type);
943 goto out;
944 }
945
946 err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
947 if (err) {
948 ubifs_err(c, "expected node type %d", type);
949 return err;
950 }
951
952 rlen = le32_to_cpu(ch->len);
953 if (rlen != len) {
954 ubifs_err(c, "bad node length %d, expected %d", rlen, len);
955 goto out;
956 }
957
958 return 0;
959
960out:
961 ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);
962 ubifs_dump_node(c, buf);
963 dump_stack();
964 return -EINVAL;
965}
966
967/**
968 * ubifs_read_node - read node.
969 * @c: UBIFS file-system description object
970 * @buf: buffer to read to
971 * @type: node type
972 * @len: node length (not aligned)
973 * @lnum: logical eraseblock number
974 * @offs: offset within the logical eraseblock
975 *
976 * This function reads a node of known type and and length, checks it and
977 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
978 * and a negative error code in case of failure.
979 */
980int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
981 int lnum, int offs)
982{
983 int err, l;
984 struct ubifs_ch *ch = buf;
985
986 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
987 ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
988 ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
989 ubifs_assert(!(offs & 7) && offs < c->leb_size);
990 ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
991
992 err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
993 if (err && err != -EBADMSG)
994 return err;
995
996 if (type != ch->node_type) {
997 ubifs_errc(c, "bad node type (%d but expected %d)",
998 ch->node_type, type);
999 goto out;
1000 }
1001
1002 err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
1003 if (err) {
1004 ubifs_errc(c, "expected node type %d", type);
1005 return err;
1006 }
1007
1008 l = le32_to_cpu(ch->len);
1009 if (l != len) {
1010 ubifs_errc(c, "bad node length %d, expected %d", l, len);
1011 goto out;
1012 }
1013
1014 return 0;
1015
1016out:
1017 ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum,
1018 offs, ubi_is_mapped(c->ubi, lnum));
1019 if (!c->probing) {
1020 ubifs_dump_node(c, buf);
1021 dump_stack();
1022 }
1023 return -EINVAL;
1024}
1025
1026/**
1027 * ubifs_wbuf_init - initialize write-buffer.
1028 * @c: UBIFS file-system description object
1029 * @wbuf: write-buffer to initialize
1030 *
1031 * This function initializes write-buffer. Returns zero in case of success
1032 * %-ENOMEM in case of failure.
1033 */
1034int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
1035{
1036 size_t size;
1037
1038 wbuf->buf = kmalloc(c->max_write_size, GFP_KERNEL);
1039 if (!wbuf->buf)
1040 return -ENOMEM;
1041
1042 size = (c->max_write_size / UBIFS_CH_SZ + 1) * sizeof(ino_t);
1043 wbuf->inodes = kmalloc(size, GFP_KERNEL);
1044 if (!wbuf->inodes) {
1045 kfree(wbuf->buf);
1046 wbuf->buf = NULL;
1047 return -ENOMEM;
1048 }
1049
1050 wbuf->used = 0;
1051 wbuf->lnum = wbuf->offs = -1;
1052 /*
1053 * If the LEB starts at the max. write size aligned address, then
1054 * write-buffer size has to be set to @c->max_write_size. Otherwise,
1055 * set it to something smaller so that it ends at the closest max.
1056 * write size boundary.
1057 */
1058 size = c->max_write_size - (c->leb_start % c->max_write_size);
1059 wbuf->avail = wbuf->size = size;
1060 wbuf->sync_callback = NULL;
1061 mutex_init(&wbuf->io_mutex);
1062 spin_lock_init(&wbuf->lock);
1063 wbuf->c = c;
1064 wbuf->next_ino = 0;
1065
1066 hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1067 wbuf->timer.function = wbuf_timer_callback_nolock;
1068 return 0;
1069}
1070
1071/**
1072 * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array.
1073 * @wbuf: the write-buffer where to add
1074 * @inum: the inode number
1075 *
1076 * This function adds an inode number to the inode array of the write-buffer.
1077 */
1078void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum)
1079{
1080 if (!wbuf->buf)
1081 /* NOR flash or something similar */
1082 return;
1083
1084 spin_lock(&wbuf->lock);
1085 if (wbuf->used)
1086 wbuf->inodes[wbuf->next_ino++] = inum;
1087 spin_unlock(&wbuf->lock);
1088}
1089
1090/**
1091 * wbuf_has_ino - returns if the wbuf contains data from the inode.
1092 * @wbuf: the write-buffer
1093 * @inum: the inode number
1094 *
1095 * This function returns with %1 if the write-buffer contains some data from the
1096 * given inode otherwise it returns with %0.
1097 */
1098static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum)
1099{
1100 int i, ret = 0;
1101
1102 spin_lock(&wbuf->lock);
1103 for (i = 0; i < wbuf->next_ino; i++)
1104 if (inum == wbuf->inodes[i]) {
1105 ret = 1;
1106 break;
1107 }
1108 spin_unlock(&wbuf->lock);
1109
1110 return ret;
1111}
1112
1113/**
1114 * ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode.
1115 * @c: UBIFS file-system description object
1116 * @inode: inode to synchronize
1117 *
1118 * This function synchronizes write-buffers which contain nodes belonging to
1119 * @inode. Returns zero in case of success and a negative error code in case of
1120 * failure.
1121 */
1122int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)
1123{
1124 int i, err = 0;
1125
1126 for (i = 0; i < c->jhead_cnt; i++) {
1127 struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
1128
1129 if (i == GCHD)
1130 /*
1131 * GC head is special, do not look at it. Even if the
1132 * head contains something related to this inode, it is
1133 * a _copy_ of corresponding on-flash node which sits
1134 * somewhere else.
1135 */
1136 continue;
1137
1138 if (!wbuf_has_ino(wbuf, inode->i_ino))
1139 continue;
1140
1141 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
1142 if (wbuf_has_ino(wbuf, inode->i_ino))
1143 err = ubifs_wbuf_sync_nolock(wbuf);
1144 mutex_unlock(&wbuf->io_mutex);
1145
1146 if (err) {
1147 ubifs_ro_mode(c, err);
1148 return err;
1149 }
1150 }
1151 return 0;
1152}