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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) International Business Machines Corp., 2006
4 *
5 * Author: Artem Bityutskiy (Битюцкий Артём)
6 */
7
8/* This file mostly implements UBI kernel API functions */
9
10#include <linux/module.h>
11#include <linux/err.h>
12#include <linux/slab.h>
13#include <linux/namei.h>
14#include <linux/fs.h>
15#include <asm/div64.h>
16#include "ubi.h"
17
18/**
19 * ubi_do_get_device_info - get information about UBI device.
20 * @ubi: UBI device description object
21 * @di: the information is stored here
22 *
23 * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
24 * device is locked and cannot disappear.
25 */
26void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
27{
28 di->ubi_num = ubi->ubi_num;
29 di->leb_size = ubi->leb_size;
30 di->leb_start = ubi->leb_start;
31 di->min_io_size = ubi->min_io_size;
32 di->max_write_size = ubi->max_write_size;
33 di->ro_mode = ubi->ro_mode;
34 di->cdev = ubi->cdev.dev;
35}
36EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
37
38/**
39 * ubi_get_device_info - get information about UBI device.
40 * @ubi_num: UBI device number
41 * @di: the information is stored here
42 *
43 * This function returns %0 in case of success, %-EINVAL if the UBI device
44 * number is invalid, and %-ENODEV if there is no such UBI device.
45 */
46int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
47{
48 struct ubi_device *ubi;
49
50 if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
51 return -EINVAL;
52 ubi = ubi_get_device(ubi_num);
53 if (!ubi)
54 return -ENODEV;
55 ubi_do_get_device_info(ubi, di);
56 ubi_put_device(ubi);
57 return 0;
58}
59EXPORT_SYMBOL_GPL(ubi_get_device_info);
60
61/**
62 * ubi_do_get_volume_info - get information about UBI volume.
63 * @ubi: UBI device description object
64 * @vol: volume description object
65 * @vi: the information is stored here
66 */
67void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
68 struct ubi_volume_info *vi)
69{
70 vi->vol_id = vol->vol_id;
71 vi->ubi_num = ubi->ubi_num;
72 vi->size = vol->reserved_pebs;
73 vi->used_bytes = vol->used_bytes;
74 vi->vol_type = vol->vol_type;
75 vi->corrupted = vol->corrupted;
76 vi->upd_marker = vol->upd_marker;
77 vi->alignment = vol->alignment;
78 vi->usable_leb_size = vol->usable_leb_size;
79 vi->name_len = vol->name_len;
80 vi->name = vol->name;
81 vi->cdev = vol->cdev.dev;
82 vi->dev = &vol->dev;
83}
84
85/**
86 * ubi_get_volume_info - get information about UBI volume.
87 * @desc: volume descriptor
88 * @vi: the information is stored here
89 */
90void ubi_get_volume_info(struct ubi_volume_desc *desc,
91 struct ubi_volume_info *vi)
92{
93 ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
94}
95EXPORT_SYMBOL_GPL(ubi_get_volume_info);
96
97/**
98 * ubi_open_volume - open UBI volume.
99 * @ubi_num: UBI device number
100 * @vol_id: volume ID
101 * @mode: open mode
102 *
103 * The @mode parameter specifies if the volume should be opened in read-only
104 * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
105 * nobody else will be able to open this volume. UBI allows to have many volume
106 * readers and one writer at a time.
107 *
108 * If a static volume is being opened for the first time since boot, it will be
109 * checked by this function, which means it will be fully read and the CRC
110 * checksum of each logical eraseblock will be checked.
111 *
112 * This function returns volume descriptor in case of success and a negative
113 * error code in case of failure.
114 */
115struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
116{
117 int err;
118 struct ubi_volume_desc *desc;
119 struct ubi_device *ubi;
120 struct ubi_volume *vol;
121
122 dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
123
124 if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
125 return ERR_PTR(-EINVAL);
126
127 if (mode != UBI_READONLY && mode != UBI_READWRITE &&
128 mode != UBI_EXCLUSIVE && mode != UBI_METAONLY)
129 return ERR_PTR(-EINVAL);
130
131 /*
132 * First of all, we have to get the UBI device to prevent its removal.
133 */
134 ubi = ubi_get_device(ubi_num);
135 if (!ubi)
136 return ERR_PTR(-ENODEV);
137
138 if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
139 err = -EINVAL;
140 goto out_put_ubi;
141 }
142
143 desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
144 if (!desc) {
145 err = -ENOMEM;
146 goto out_put_ubi;
147 }
148
149 err = -ENODEV;
150 if (!try_module_get(THIS_MODULE))
151 goto out_free;
152
153 spin_lock(&ubi->volumes_lock);
154 vol = ubi->volumes[vol_id];
155 if (!vol)
156 goto out_unlock;
157
158 err = -EBUSY;
159 switch (mode) {
160 case UBI_READONLY:
161 if (vol->exclusive)
162 goto out_unlock;
163 vol->readers += 1;
164 break;
165
166 case UBI_READWRITE:
167 if (vol->exclusive || vol->writers > 0)
168 goto out_unlock;
169 vol->writers += 1;
170 break;
171
172 case UBI_EXCLUSIVE:
173 if (vol->exclusive || vol->writers || vol->readers ||
174 vol->metaonly)
175 goto out_unlock;
176 vol->exclusive = 1;
177 break;
178
179 case UBI_METAONLY:
180 if (vol->metaonly || vol->exclusive)
181 goto out_unlock;
182 vol->metaonly = 1;
183 break;
184 }
185 get_device(&vol->dev);
186 vol->ref_count += 1;
187 spin_unlock(&ubi->volumes_lock);
188
189 desc->vol = vol;
190 desc->mode = mode;
191
192 mutex_lock(&ubi->ckvol_mutex);
193 if (!vol->checked && !vol->skip_check) {
194 /* This is the first open - check the volume */
195 err = ubi_check_volume(ubi, vol_id);
196 if (err < 0) {
197 mutex_unlock(&ubi->ckvol_mutex);
198 ubi_close_volume(desc);
199 return ERR_PTR(err);
200 }
201 if (err == 1) {
202 ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
203 vol_id, ubi->ubi_num);
204 vol->corrupted = 1;
205 }
206 vol->checked = 1;
207 }
208 mutex_unlock(&ubi->ckvol_mutex);
209
210 return desc;
211
212out_unlock:
213 spin_unlock(&ubi->volumes_lock);
214 module_put(THIS_MODULE);
215out_free:
216 kfree(desc);
217out_put_ubi:
218 ubi_err(ubi, "cannot open device %d, volume %d, error %d",
219 ubi_num, vol_id, err);
220 ubi_put_device(ubi);
221 return ERR_PTR(err);
222}
223EXPORT_SYMBOL_GPL(ubi_open_volume);
224
225/**
226 * ubi_open_volume_nm - open UBI volume by name.
227 * @ubi_num: UBI device number
228 * @name: volume name
229 * @mode: open mode
230 *
231 * This function is similar to 'ubi_open_volume()', but opens a volume by name.
232 */
233struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
234 int mode)
235{
236 int i, vol_id = -1, len;
237 struct ubi_device *ubi;
238 struct ubi_volume_desc *ret;
239
240 dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
241
242 if (!name)
243 return ERR_PTR(-EINVAL);
244
245 len = strnlen(name, UBI_VOL_NAME_MAX + 1);
246 if (len > UBI_VOL_NAME_MAX)
247 return ERR_PTR(-EINVAL);
248
249 if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
250 return ERR_PTR(-EINVAL);
251
252 ubi = ubi_get_device(ubi_num);
253 if (!ubi)
254 return ERR_PTR(-ENODEV);
255
256 spin_lock(&ubi->volumes_lock);
257 /* Walk all volumes of this UBI device */
258 for (i = 0; i < ubi->vtbl_slots; i++) {
259 struct ubi_volume *vol = ubi->volumes[i];
260
261 if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
262 vol_id = i;
263 break;
264 }
265 }
266 spin_unlock(&ubi->volumes_lock);
267
268 if (vol_id >= 0)
269 ret = ubi_open_volume(ubi_num, vol_id, mode);
270 else
271 ret = ERR_PTR(-ENODEV);
272
273 /*
274 * We should put the UBI device even in case of success, because
275 * 'ubi_open_volume()' took a reference as well.
276 */
277 ubi_put_device(ubi);
278 return ret;
279}
280EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
281
282/**
283 * ubi_open_volume_path - open UBI volume by its character device node path.
284 * @pathname: volume character device node path
285 * @mode: open mode
286 *
287 * This function is similar to 'ubi_open_volume()', but opens a volume the path
288 * to its character device node.
289 */
290struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
291{
292 int error, ubi_num, vol_id;
293 struct path path;
294 struct kstat stat;
295
296 dbg_gen("open volume %s, mode %d", pathname, mode);
297
298 if (!pathname || !*pathname)
299 return ERR_PTR(-EINVAL);
300
301 error = kern_path(pathname, LOOKUP_FOLLOW, &path);
302 if (error)
303 return ERR_PTR(error);
304
305 error = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
306 path_put(&path);
307 if (error)
308 return ERR_PTR(error);
309
310 if (!S_ISCHR(stat.mode))
311 return ERR_PTR(-EINVAL);
312
313 ubi_num = ubi_major2num(MAJOR(stat.rdev));
314 vol_id = MINOR(stat.rdev) - 1;
315
316 if (vol_id >= 0 && ubi_num >= 0)
317 return ubi_open_volume(ubi_num, vol_id, mode);
318 return ERR_PTR(-ENODEV);
319}
320EXPORT_SYMBOL_GPL(ubi_open_volume_path);
321
322/**
323 * ubi_close_volume - close UBI volume.
324 * @desc: volume descriptor
325 */
326void ubi_close_volume(struct ubi_volume_desc *desc)
327{
328 struct ubi_volume *vol = desc->vol;
329 struct ubi_device *ubi = vol->ubi;
330
331 dbg_gen("close device %d, volume %d, mode %d",
332 ubi->ubi_num, vol->vol_id, desc->mode);
333
334 spin_lock(&ubi->volumes_lock);
335 switch (desc->mode) {
336 case UBI_READONLY:
337 vol->readers -= 1;
338 break;
339 case UBI_READWRITE:
340 vol->writers -= 1;
341 break;
342 case UBI_EXCLUSIVE:
343 vol->exclusive = 0;
344 break;
345 case UBI_METAONLY:
346 vol->metaonly = 0;
347 break;
348 }
349 vol->ref_count -= 1;
350 spin_unlock(&ubi->volumes_lock);
351
352 kfree(desc);
353 put_device(&vol->dev);
354 ubi_put_device(ubi);
355 module_put(THIS_MODULE);
356}
357EXPORT_SYMBOL_GPL(ubi_close_volume);
358
359/**
360 * leb_read_sanity_check - does sanity checks on read requests.
361 * @desc: volume descriptor
362 * @lnum: logical eraseblock number to read from
363 * @offset: offset within the logical eraseblock to read from
364 * @len: how many bytes to read
365 *
366 * This function is used by ubi_leb_read() and ubi_leb_read_sg()
367 * to perform sanity checks.
368 */
369static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
370 int offset, int len)
371{
372 struct ubi_volume *vol = desc->vol;
373 struct ubi_device *ubi = vol->ubi;
374 int vol_id = vol->vol_id;
375
376 if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
377 lnum >= vol->used_ebs || offset < 0 || len < 0 ||
378 offset + len > vol->usable_leb_size)
379 return -EINVAL;
380
381 if (vol->vol_type == UBI_STATIC_VOLUME) {
382 if (vol->used_ebs == 0)
383 /* Empty static UBI volume */
384 return 0;
385 if (lnum == vol->used_ebs - 1 &&
386 offset + len > vol->last_eb_bytes)
387 return -EINVAL;
388 }
389
390 if (vol->upd_marker)
391 return -EBADF;
392
393 return 0;
394}
395
396/**
397 * ubi_leb_read - read data.
398 * @desc: volume descriptor
399 * @lnum: logical eraseblock number to read from
400 * @buf: buffer where to store the read data
401 * @offset: offset within the logical eraseblock to read from
402 * @len: how many bytes to read
403 * @check: whether UBI has to check the read data's CRC or not.
404 *
405 * This function reads data from offset @offset of logical eraseblock @lnum and
406 * stores the data at @buf. When reading from static volumes, @check specifies
407 * whether the data has to be checked or not. If yes, the whole logical
408 * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
409 * checksum is per-eraseblock). So checking may substantially slow down the
410 * read speed. The @check argument is ignored for dynamic volumes.
411 *
412 * In case of success, this function returns zero. In case of failure, this
413 * function returns a negative error code.
414 *
415 * %-EBADMSG error code is returned:
416 * o for both static and dynamic volumes if MTD driver has detected a data
417 * integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
418 * o for static volumes in case of data CRC mismatch.
419 *
420 * If the volume is damaged because of an interrupted update this function just
421 * returns immediately with %-EBADF error code.
422 */
423int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
424 int len, int check)
425{
426 struct ubi_volume *vol = desc->vol;
427 struct ubi_device *ubi = vol->ubi;
428 int err, vol_id = vol->vol_id;
429
430 dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
431
432 err = leb_read_sanity_check(desc, lnum, offset, len);
433 if (err < 0)
434 return err;
435
436 if (len == 0)
437 return 0;
438
439 err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
440 if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
441 ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
442 vol->corrupted = 1;
443 }
444
445 return err;
446}
447EXPORT_SYMBOL_GPL(ubi_leb_read);
448
449
450/**
451 * ubi_leb_read_sg - read data into a scatter gather list.
452 * @desc: volume descriptor
453 * @lnum: logical eraseblock number to read from
454 * @sgl: UBI scatter gather list to store the read data
455 * @offset: offset within the logical eraseblock to read from
456 * @len: how many bytes to read
457 * @check: whether UBI has to check the read data's CRC or not.
458 *
459 * This function works exactly like ubi_leb_read_sg(). But instead of
460 * storing the read data into a buffer it writes to an UBI scatter gather
461 * list.
462 */
463int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
464 int offset, int len, int check)
465{
466 struct ubi_volume *vol = desc->vol;
467 struct ubi_device *ubi = vol->ubi;
468 int err, vol_id = vol->vol_id;
469
470 dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
471
472 err = leb_read_sanity_check(desc, lnum, offset, len);
473 if (err < 0)
474 return err;
475
476 if (len == 0)
477 return 0;
478
479 err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
480 if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
481 ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
482 vol->corrupted = 1;
483 }
484
485 return err;
486}
487EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
488
489/**
490 * ubi_leb_write - write data.
491 * @desc: volume descriptor
492 * @lnum: logical eraseblock number to write to
493 * @buf: data to write
494 * @offset: offset within the logical eraseblock where to write
495 * @len: how many bytes to write
496 *
497 * This function writes @len bytes of data from @buf to offset @offset of
498 * logical eraseblock @lnum.
499 *
500 * This function takes care of physical eraseblock write failures. If write to
501 * the physical eraseblock write operation fails, the logical eraseblock is
502 * re-mapped to another physical eraseblock, the data is recovered, and the
503 * write finishes. UBI has a pool of reserved physical eraseblocks for this.
504 *
505 * If all the data were successfully written, zero is returned. If an error
506 * occurred and UBI has not been able to recover from it, this function returns
507 * a negative error code. Note, in case of an error, it is possible that
508 * something was still written to the flash media, but that may be some
509 * garbage.
510 *
511 * If the volume is damaged because of an interrupted update this function just
512 * returns immediately with %-EBADF code.
513 */
514int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
515 int offset, int len)
516{
517 struct ubi_volume *vol = desc->vol;
518 struct ubi_device *ubi = vol->ubi;
519 int vol_id = vol->vol_id;
520
521 dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
522
523 if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
524 return -EINVAL;
525
526 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
527 return -EROFS;
528
529 if (!ubi_leb_valid(vol, lnum) || offset < 0 || len < 0 ||
530 offset + len > vol->usable_leb_size ||
531 offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
532 return -EINVAL;
533
534 if (vol->upd_marker)
535 return -EBADF;
536
537 if (len == 0)
538 return 0;
539
540 return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
541}
542EXPORT_SYMBOL_GPL(ubi_leb_write);
543
544/*
545 * ubi_leb_change - change logical eraseblock atomically.
546 * @desc: volume descriptor
547 * @lnum: logical eraseblock number to change
548 * @buf: data to write
549 * @len: how many bytes to write
550 *
551 * This function changes the contents of a logical eraseblock atomically. @buf
552 * has to contain new logical eraseblock data, and @len - the length of the
553 * data, which has to be aligned. The length may be shorter than the logical
554 * eraseblock size, ant the logical eraseblock may be appended to more times
555 * later on. This function guarantees that in case of an unclean reboot the old
556 * contents is preserved. Returns zero in case of success and a negative error
557 * code in case of failure.
558 */
559int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
560 int len)
561{
562 struct ubi_volume *vol = desc->vol;
563 struct ubi_device *ubi = vol->ubi;
564 int vol_id = vol->vol_id;
565
566 dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
567
568 if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
569 return -EINVAL;
570
571 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
572 return -EROFS;
573
574 if (!ubi_leb_valid(vol, lnum) || len < 0 ||
575 len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
576 return -EINVAL;
577
578 if (vol->upd_marker)
579 return -EBADF;
580
581 if (len == 0)
582 return 0;
583
584 return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
585}
586EXPORT_SYMBOL_GPL(ubi_leb_change);
587
588/**
589 * ubi_leb_erase - erase logical eraseblock.
590 * @desc: volume descriptor
591 * @lnum: logical eraseblock number
592 *
593 * This function un-maps logical eraseblock @lnum and synchronously erases the
594 * correspondent physical eraseblock. Returns zero in case of success and a
595 * negative error code in case of failure.
596 *
597 * If the volume is damaged because of an interrupted update this function just
598 * returns immediately with %-EBADF code.
599 */
600int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
601{
602 struct ubi_volume *vol = desc->vol;
603 struct ubi_device *ubi = vol->ubi;
604 int err;
605
606 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
607
608 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
609 return -EROFS;
610
611 if (!ubi_leb_valid(vol, lnum))
612 return -EINVAL;
613
614 if (vol->upd_marker)
615 return -EBADF;
616
617 err = ubi_eba_unmap_leb(ubi, vol, lnum);
618 if (err)
619 return err;
620
621 return ubi_wl_flush(ubi, vol->vol_id, lnum);
622}
623EXPORT_SYMBOL_GPL(ubi_leb_erase);
624
625/**
626 * ubi_leb_unmap - un-map logical eraseblock.
627 * @desc: volume descriptor
628 * @lnum: logical eraseblock number
629 *
630 * This function un-maps logical eraseblock @lnum and schedules the
631 * corresponding physical eraseblock for erasure, so that it will eventually be
632 * physically erased in background. This operation is much faster than the
633 * erase operation.
634 *
635 * Unlike erase, the un-map operation does not guarantee that the logical
636 * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
637 * example, if several logical eraseblocks are un-mapped, and an unclean reboot
638 * happens after this, the logical eraseblocks will not necessarily be
639 * un-mapped again when this MTD device is attached. They may actually be
640 * mapped to the same physical eraseblocks again. So, this function has to be
641 * used with care.
642 *
643 * In other words, when un-mapping a logical eraseblock, UBI does not store
644 * any information about this on the flash media, it just marks the logical
645 * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
646 * eraseblock is physically erased, it will be mapped again to the same logical
647 * eraseblock when the MTD device is attached again.
648 *
649 * The main and obvious use-case of this function is when the contents of a
650 * logical eraseblock has to be re-written. Then it is much more efficient to
651 * first un-map it, then write new data, rather than first erase it, then write
652 * new data. Note, once new data has been written to the logical eraseblock,
653 * UBI guarantees that the old contents has gone forever. In other words, if an
654 * unclean reboot happens after the logical eraseblock has been un-mapped and
655 * then written to, it will contain the last written data.
656 *
657 * This function returns zero in case of success and a negative error code in
658 * case of failure. If the volume is damaged because of an interrupted update
659 * this function just returns immediately with %-EBADF code.
660 */
661int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
662{
663 struct ubi_volume *vol = desc->vol;
664 struct ubi_device *ubi = vol->ubi;
665
666 dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
667
668 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
669 return -EROFS;
670
671 if (!ubi_leb_valid(vol, lnum))
672 return -EINVAL;
673
674 if (vol->upd_marker)
675 return -EBADF;
676
677 return ubi_eba_unmap_leb(ubi, vol, lnum);
678}
679EXPORT_SYMBOL_GPL(ubi_leb_unmap);
680
681/**
682 * ubi_leb_map - map logical eraseblock to a physical eraseblock.
683 * @desc: volume descriptor
684 * @lnum: logical eraseblock number
685 *
686 * This function maps an un-mapped logical eraseblock @lnum to a physical
687 * eraseblock. This means, that after a successful invocation of this
688 * function the logical eraseblock @lnum will be empty (contain only %0xFF
689 * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
690 * happens.
691 *
692 * This function returns zero in case of success, %-EBADF if the volume is
693 * damaged because of an interrupted update, %-EBADMSG if the logical
694 * eraseblock is already mapped, and other negative error codes in case of
695 * other failures.
696 */
697int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
698{
699 struct ubi_volume *vol = desc->vol;
700 struct ubi_device *ubi = vol->ubi;
701
702 dbg_gen("map LEB %d:%d", vol->vol_id, lnum);
703
704 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
705 return -EROFS;
706
707 if (!ubi_leb_valid(vol, lnum))
708 return -EINVAL;
709
710 if (vol->upd_marker)
711 return -EBADF;
712
713 if (ubi_eba_is_mapped(vol, lnum))
714 return -EBADMSG;
715
716 return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
717}
718EXPORT_SYMBOL_GPL(ubi_leb_map);
719
720/**
721 * ubi_is_mapped - check if logical eraseblock is mapped.
722 * @desc: volume descriptor
723 * @lnum: logical eraseblock number
724 *
725 * This function checks if logical eraseblock @lnum is mapped to a physical
726 * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
727 * mean it will still be un-mapped after the UBI device is re-attached. The
728 * logical eraseblock may become mapped to the physical eraseblock it was last
729 * mapped to.
730 *
731 * This function returns %1 if the LEB is mapped, %0 if not, and a negative
732 * error code in case of failure. If the volume is damaged because of an
733 * interrupted update this function just returns immediately with %-EBADF error
734 * code.
735 */
736int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
737{
738 struct ubi_volume *vol = desc->vol;
739
740 dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
741
742 if (!ubi_leb_valid(vol, lnum))
743 return -EINVAL;
744
745 if (vol->upd_marker)
746 return -EBADF;
747
748 return ubi_eba_is_mapped(vol, lnum);
749}
750EXPORT_SYMBOL_GPL(ubi_is_mapped);
751
752/**
753 * ubi_sync - synchronize UBI device buffers.
754 * @ubi_num: UBI device to synchronize
755 *
756 * The underlying MTD device may cache data in hardware or in software. This
757 * function ensures the caches are flushed. Returns zero in case of success and
758 * a negative error code in case of failure.
759 */
760int ubi_sync(int ubi_num)
761{
762 struct ubi_device *ubi;
763
764 ubi = ubi_get_device(ubi_num);
765 if (!ubi)
766 return -ENODEV;
767
768 mtd_sync(ubi->mtd);
769 ubi_put_device(ubi);
770 return 0;
771}
772EXPORT_SYMBOL_GPL(ubi_sync);
773
774/**
775 * ubi_flush - flush UBI work queue.
776 * @ubi_num: UBI device to flush work queue
777 * @vol_id: volume id to flush for
778 * @lnum: logical eraseblock number to flush for
779 *
780 * This function executes all pending works for a particular volume id / logical
781 * eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
782 * a wildcard for all of the corresponding volume numbers or logical
783 * eraseblock numbers. It returns zero in case of success and a negative error
784 * code in case of failure.
785 */
786int ubi_flush(int ubi_num, int vol_id, int lnum)
787{
788 struct ubi_device *ubi;
789 int err = 0;
790
791 ubi = ubi_get_device(ubi_num);
792 if (!ubi)
793 return -ENODEV;
794
795 err = ubi_wl_flush(ubi, vol_id, lnum);
796 ubi_put_device(ubi);
797 return err;
798}
799EXPORT_SYMBOL_GPL(ubi_flush);
800
801BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
802
803/**
804 * ubi_register_volume_notifier - register a volume notifier.
805 * @nb: the notifier description object
806 * @ignore_existing: if non-zero, do not send "added" notification for all
807 * already existing volumes
808 *
809 * This function registers a volume notifier, which means that
810 * 'nb->notifier_call()' will be invoked when an UBI volume is created,
811 * removed, re-sized, re-named, or updated. The first argument of the function
812 * is the notification type. The second argument is pointer to a
813 * &struct ubi_notification object which describes the notification event.
814 * Using UBI API from the volume notifier is prohibited.
815 *
816 * This function returns zero in case of success and a negative error code
817 * in case of failure.
818 */
819int ubi_register_volume_notifier(struct notifier_block *nb,
820 int ignore_existing)
821{
822 int err;
823
824 err = blocking_notifier_chain_register(&ubi_notifiers, nb);
825 if (err != 0)
826 return err;
827 if (ignore_existing)
828 return 0;
829
830 /*
831 * We are going to walk all UBI devices and all volumes, and
832 * notify the user about existing volumes by the %UBI_VOLUME_ADDED
833 * event. We have to lock the @ubi_devices_mutex to make sure UBI
834 * devices do not disappear.
835 */
836 mutex_lock(&ubi_devices_mutex);
837 ubi_enumerate_volumes(nb);
838 mutex_unlock(&ubi_devices_mutex);
839
840 return err;
841}
842EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
843
844/**
845 * ubi_unregister_volume_notifier - unregister the volume notifier.
846 * @nb: the notifier description object
847 *
848 * This function unregisters volume notifier @nm and returns zero in case of
849 * success and a negative error code in case of failure.
850 */
851int ubi_unregister_volume_notifier(struct notifier_block *nb)
852{
853 return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
854}
855EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);
1/*
2 * Copyright (c) International Business Machines Corp., 2006
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 *
18 * Author: Artem Bityutskiy (Битюцкий Артём)
19 */
20
21/* This file mostly implements UBI kernel API functions */
22
23#include <linux/module.h>
24#include <linux/err.h>
25#include <linux/slab.h>
26#include <linux/namei.h>
27#include <linux/fs.h>
28#include <asm/div64.h>
29#include "ubi.h"
30
31/**
32 * ubi_do_get_device_info - get information about UBI device.
33 * @ubi: UBI device description object
34 * @di: the information is stored here
35 *
36 * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
37 * device is locked and cannot disappear.
38 */
39void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
40{
41 di->ubi_num = ubi->ubi_num;
42 di->leb_size = ubi->leb_size;
43 di->leb_start = ubi->leb_start;
44 di->min_io_size = ubi->min_io_size;
45 di->max_write_size = ubi->max_write_size;
46 di->ro_mode = ubi->ro_mode;
47 di->cdev = ubi->cdev.dev;
48}
49EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
50
51/**
52 * ubi_get_device_info - get information about UBI device.
53 * @ubi_num: UBI device number
54 * @di: the information is stored here
55 *
56 * This function returns %0 in case of success, %-EINVAL if the UBI device
57 * number is invalid, and %-ENODEV if there is no such UBI device.
58 */
59int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
60{
61 struct ubi_device *ubi;
62
63 if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
64 return -EINVAL;
65 ubi = ubi_get_device(ubi_num);
66 if (!ubi)
67 return -ENODEV;
68 ubi_do_get_device_info(ubi, di);
69 ubi_put_device(ubi);
70 return 0;
71}
72EXPORT_SYMBOL_GPL(ubi_get_device_info);
73
74/**
75 * ubi_do_get_volume_info - get information about UBI volume.
76 * @ubi: UBI device description object
77 * @vol: volume description object
78 * @vi: the information is stored here
79 */
80void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
81 struct ubi_volume_info *vi)
82{
83 vi->vol_id = vol->vol_id;
84 vi->ubi_num = ubi->ubi_num;
85 vi->size = vol->reserved_pebs;
86 vi->used_bytes = vol->used_bytes;
87 vi->vol_type = vol->vol_type;
88 vi->corrupted = vol->corrupted;
89 vi->upd_marker = vol->upd_marker;
90 vi->alignment = vol->alignment;
91 vi->usable_leb_size = vol->usable_leb_size;
92 vi->name_len = vol->name_len;
93 vi->name = vol->name;
94 vi->cdev = vol->cdev.dev;
95}
96
97/**
98 * ubi_get_volume_info - get information about UBI volume.
99 * @desc: volume descriptor
100 * @vi: the information is stored here
101 */
102void ubi_get_volume_info(struct ubi_volume_desc *desc,
103 struct ubi_volume_info *vi)
104{
105 ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
106}
107EXPORT_SYMBOL_GPL(ubi_get_volume_info);
108
109/**
110 * ubi_open_volume - open UBI volume.
111 * @ubi_num: UBI device number
112 * @vol_id: volume ID
113 * @mode: open mode
114 *
115 * The @mode parameter specifies if the volume should be opened in read-only
116 * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
117 * nobody else will be able to open this volume. UBI allows to have many volume
118 * readers and one writer at a time.
119 *
120 * If a static volume is being opened for the first time since boot, it will be
121 * checked by this function, which means it will be fully read and the CRC
122 * checksum of each logical eraseblock will be checked.
123 *
124 * This function returns volume descriptor in case of success and a negative
125 * error code in case of failure.
126 */
127struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
128{
129 int err;
130 struct ubi_volume_desc *desc;
131 struct ubi_device *ubi;
132 struct ubi_volume *vol;
133
134 dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
135
136 if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
137 return ERR_PTR(-EINVAL);
138
139 if (mode != UBI_READONLY && mode != UBI_READWRITE &&
140 mode != UBI_EXCLUSIVE && mode != UBI_METAONLY)
141 return ERR_PTR(-EINVAL);
142
143 /*
144 * First of all, we have to get the UBI device to prevent its removal.
145 */
146 ubi = ubi_get_device(ubi_num);
147 if (!ubi)
148 return ERR_PTR(-ENODEV);
149
150 if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
151 err = -EINVAL;
152 goto out_put_ubi;
153 }
154
155 desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
156 if (!desc) {
157 err = -ENOMEM;
158 goto out_put_ubi;
159 }
160
161 err = -ENODEV;
162 if (!try_module_get(THIS_MODULE))
163 goto out_free;
164
165 spin_lock(&ubi->volumes_lock);
166 vol = ubi->volumes[vol_id];
167 if (!vol)
168 goto out_unlock;
169
170 err = -EBUSY;
171 switch (mode) {
172 case UBI_READONLY:
173 if (vol->exclusive)
174 goto out_unlock;
175 vol->readers += 1;
176 break;
177
178 case UBI_READWRITE:
179 if (vol->exclusive || vol->writers > 0)
180 goto out_unlock;
181 vol->writers += 1;
182 break;
183
184 case UBI_EXCLUSIVE:
185 if (vol->exclusive || vol->writers || vol->readers ||
186 vol->metaonly)
187 goto out_unlock;
188 vol->exclusive = 1;
189 break;
190
191 case UBI_METAONLY:
192 if (vol->metaonly || vol->exclusive)
193 goto out_unlock;
194 vol->metaonly = 1;
195 break;
196 }
197 get_device(&vol->dev);
198 vol->ref_count += 1;
199 spin_unlock(&ubi->volumes_lock);
200
201 desc->vol = vol;
202 desc->mode = mode;
203
204 mutex_lock(&ubi->ckvol_mutex);
205 if (!vol->checked) {
206 /* This is the first open - check the volume */
207 err = ubi_check_volume(ubi, vol_id);
208 if (err < 0) {
209 mutex_unlock(&ubi->ckvol_mutex);
210 ubi_close_volume(desc);
211 return ERR_PTR(err);
212 }
213 if (err == 1) {
214 ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
215 vol_id, ubi->ubi_num);
216 vol->corrupted = 1;
217 }
218 vol->checked = 1;
219 }
220 mutex_unlock(&ubi->ckvol_mutex);
221
222 return desc;
223
224out_unlock:
225 spin_unlock(&ubi->volumes_lock);
226 module_put(THIS_MODULE);
227out_free:
228 kfree(desc);
229out_put_ubi:
230 ubi_put_device(ubi);
231 ubi_err(ubi, "cannot open device %d, volume %d, error %d",
232 ubi_num, vol_id, err);
233 return ERR_PTR(err);
234}
235EXPORT_SYMBOL_GPL(ubi_open_volume);
236
237/**
238 * ubi_open_volume_nm - open UBI volume by name.
239 * @ubi_num: UBI device number
240 * @name: volume name
241 * @mode: open mode
242 *
243 * This function is similar to 'ubi_open_volume()', but opens a volume by name.
244 */
245struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
246 int mode)
247{
248 int i, vol_id = -1, len;
249 struct ubi_device *ubi;
250 struct ubi_volume_desc *ret;
251
252 dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
253
254 if (!name)
255 return ERR_PTR(-EINVAL);
256
257 len = strnlen(name, UBI_VOL_NAME_MAX + 1);
258 if (len > UBI_VOL_NAME_MAX)
259 return ERR_PTR(-EINVAL);
260
261 if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
262 return ERR_PTR(-EINVAL);
263
264 ubi = ubi_get_device(ubi_num);
265 if (!ubi)
266 return ERR_PTR(-ENODEV);
267
268 spin_lock(&ubi->volumes_lock);
269 /* Walk all volumes of this UBI device */
270 for (i = 0; i < ubi->vtbl_slots; i++) {
271 struct ubi_volume *vol = ubi->volumes[i];
272
273 if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
274 vol_id = i;
275 break;
276 }
277 }
278 spin_unlock(&ubi->volumes_lock);
279
280 if (vol_id >= 0)
281 ret = ubi_open_volume(ubi_num, vol_id, mode);
282 else
283 ret = ERR_PTR(-ENODEV);
284
285 /*
286 * We should put the UBI device even in case of success, because
287 * 'ubi_open_volume()' took a reference as well.
288 */
289 ubi_put_device(ubi);
290 return ret;
291}
292EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
293
294/**
295 * ubi_open_volume_path - open UBI volume by its character device node path.
296 * @pathname: volume character device node path
297 * @mode: open mode
298 *
299 * This function is similar to 'ubi_open_volume()', but opens a volume the path
300 * to its character device node.
301 */
302struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
303{
304 int error, ubi_num, vol_id, mod;
305 struct inode *inode;
306 struct path path;
307
308 dbg_gen("open volume %s, mode %d", pathname, mode);
309
310 if (!pathname || !*pathname)
311 return ERR_PTR(-EINVAL);
312
313 error = kern_path(pathname, LOOKUP_FOLLOW, &path);
314 if (error)
315 return ERR_PTR(error);
316
317 inode = d_backing_inode(path.dentry);
318 mod = inode->i_mode;
319 ubi_num = ubi_major2num(imajor(inode));
320 vol_id = iminor(inode) - 1;
321 path_put(&path);
322
323 if (!S_ISCHR(mod))
324 return ERR_PTR(-EINVAL);
325 if (vol_id >= 0 && ubi_num >= 0)
326 return ubi_open_volume(ubi_num, vol_id, mode);
327 return ERR_PTR(-ENODEV);
328}
329EXPORT_SYMBOL_GPL(ubi_open_volume_path);
330
331/**
332 * ubi_close_volume - close UBI volume.
333 * @desc: volume descriptor
334 */
335void ubi_close_volume(struct ubi_volume_desc *desc)
336{
337 struct ubi_volume *vol = desc->vol;
338 struct ubi_device *ubi = vol->ubi;
339
340 dbg_gen("close device %d, volume %d, mode %d",
341 ubi->ubi_num, vol->vol_id, desc->mode);
342
343 spin_lock(&ubi->volumes_lock);
344 switch (desc->mode) {
345 case UBI_READONLY:
346 vol->readers -= 1;
347 break;
348 case UBI_READWRITE:
349 vol->writers -= 1;
350 break;
351 case UBI_EXCLUSIVE:
352 vol->exclusive = 0;
353 break;
354 case UBI_METAONLY:
355 vol->metaonly = 0;
356 break;
357 }
358 vol->ref_count -= 1;
359 spin_unlock(&ubi->volumes_lock);
360
361 kfree(desc);
362 put_device(&vol->dev);
363 ubi_put_device(ubi);
364 module_put(THIS_MODULE);
365}
366EXPORT_SYMBOL_GPL(ubi_close_volume);
367
368/**
369 * leb_read_sanity_check - does sanity checks on read requests.
370 * @desc: volume descriptor
371 * @lnum: logical eraseblock number to read from
372 * @offset: offset within the logical eraseblock to read from
373 * @len: how many bytes to read
374 *
375 * This function is used by ubi_leb_read() and ubi_leb_read_sg()
376 * to perform sanity checks.
377 */
378static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
379 int offset, int len)
380{
381 struct ubi_volume *vol = desc->vol;
382 struct ubi_device *ubi = vol->ubi;
383 int vol_id = vol->vol_id;
384
385 if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
386 lnum >= vol->used_ebs || offset < 0 || len < 0 ||
387 offset + len > vol->usable_leb_size)
388 return -EINVAL;
389
390 if (vol->vol_type == UBI_STATIC_VOLUME) {
391 if (vol->used_ebs == 0)
392 /* Empty static UBI volume */
393 return 0;
394 if (lnum == vol->used_ebs - 1 &&
395 offset + len > vol->last_eb_bytes)
396 return -EINVAL;
397 }
398
399 if (vol->upd_marker)
400 return -EBADF;
401
402 return 0;
403}
404
405/**
406 * ubi_leb_read - read data.
407 * @desc: volume descriptor
408 * @lnum: logical eraseblock number to read from
409 * @buf: buffer where to store the read data
410 * @offset: offset within the logical eraseblock to read from
411 * @len: how many bytes to read
412 * @check: whether UBI has to check the read data's CRC or not.
413 *
414 * This function reads data from offset @offset of logical eraseblock @lnum and
415 * stores the data at @buf. When reading from static volumes, @check specifies
416 * whether the data has to be checked or not. If yes, the whole logical
417 * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
418 * checksum is per-eraseblock). So checking may substantially slow down the
419 * read speed. The @check argument is ignored for dynamic volumes.
420 *
421 * In case of success, this function returns zero. In case of failure, this
422 * function returns a negative error code.
423 *
424 * %-EBADMSG error code is returned:
425 * o for both static and dynamic volumes if MTD driver has detected a data
426 * integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
427 * o for static volumes in case of data CRC mismatch.
428 *
429 * If the volume is damaged because of an interrupted update this function just
430 * returns immediately with %-EBADF error code.
431 */
432int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
433 int len, int check)
434{
435 struct ubi_volume *vol = desc->vol;
436 struct ubi_device *ubi = vol->ubi;
437 int err, vol_id = vol->vol_id;
438
439 dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
440
441 err = leb_read_sanity_check(desc, lnum, offset, len);
442 if (err < 0)
443 return err;
444
445 if (len == 0)
446 return 0;
447
448 err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
449 if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
450 ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
451 vol->corrupted = 1;
452 }
453
454 return err;
455}
456EXPORT_SYMBOL_GPL(ubi_leb_read);
457
458
459/**
460 * ubi_leb_read_sg - read data into a scatter gather list.
461 * @desc: volume descriptor
462 * @lnum: logical eraseblock number to read from
463 * @buf: buffer where to store the read data
464 * @offset: offset within the logical eraseblock to read from
465 * @len: how many bytes to read
466 * @check: whether UBI has to check the read data's CRC or not.
467 *
468 * This function works exactly like ubi_leb_read_sg(). But instead of
469 * storing the read data into a buffer it writes to an UBI scatter gather
470 * list.
471 */
472int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
473 int offset, int len, int check)
474{
475 struct ubi_volume *vol = desc->vol;
476 struct ubi_device *ubi = vol->ubi;
477 int err, vol_id = vol->vol_id;
478
479 dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
480
481 err = leb_read_sanity_check(desc, lnum, offset, len);
482 if (err < 0)
483 return err;
484
485 if (len == 0)
486 return 0;
487
488 err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
489 if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
490 ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
491 vol->corrupted = 1;
492 }
493
494 return err;
495}
496EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
497
498/**
499 * ubi_leb_write - write data.
500 * @desc: volume descriptor
501 * @lnum: logical eraseblock number to write to
502 * @buf: data to write
503 * @offset: offset within the logical eraseblock where to write
504 * @len: how many bytes to write
505 *
506 * This function writes @len bytes of data from @buf to offset @offset of
507 * logical eraseblock @lnum.
508 *
509 * This function takes care of physical eraseblock write failures. If write to
510 * the physical eraseblock write operation fails, the logical eraseblock is
511 * re-mapped to another physical eraseblock, the data is recovered, and the
512 * write finishes. UBI has a pool of reserved physical eraseblocks for this.
513 *
514 * If all the data were successfully written, zero is returned. If an error
515 * occurred and UBI has not been able to recover from it, this function returns
516 * a negative error code. Note, in case of an error, it is possible that
517 * something was still written to the flash media, but that may be some
518 * garbage.
519 *
520 * If the volume is damaged because of an interrupted update this function just
521 * returns immediately with %-EBADF code.
522 */
523int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
524 int offset, int len)
525{
526 struct ubi_volume *vol = desc->vol;
527 struct ubi_device *ubi = vol->ubi;
528 int vol_id = vol->vol_id;
529
530 dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
531
532 if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
533 return -EINVAL;
534
535 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
536 return -EROFS;
537
538 if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
539 offset + len > vol->usable_leb_size ||
540 offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
541 return -EINVAL;
542
543 if (vol->upd_marker)
544 return -EBADF;
545
546 if (len == 0)
547 return 0;
548
549 return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
550}
551EXPORT_SYMBOL_GPL(ubi_leb_write);
552
553/*
554 * ubi_leb_change - change logical eraseblock atomically.
555 * @desc: volume descriptor
556 * @lnum: logical eraseblock number to change
557 * @buf: data to write
558 * @len: how many bytes to write
559 *
560 * This function changes the contents of a logical eraseblock atomically. @buf
561 * has to contain new logical eraseblock data, and @len - the length of the
562 * data, which has to be aligned. The length may be shorter than the logical
563 * eraseblock size, ant the logical eraseblock may be appended to more times
564 * later on. This function guarantees that in case of an unclean reboot the old
565 * contents is preserved. Returns zero in case of success and a negative error
566 * code in case of failure.
567 */
568int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
569 int len)
570{
571 struct ubi_volume *vol = desc->vol;
572 struct ubi_device *ubi = vol->ubi;
573 int vol_id = vol->vol_id;
574
575 dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
576
577 if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
578 return -EINVAL;
579
580 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
581 return -EROFS;
582
583 if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
584 len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
585 return -EINVAL;
586
587 if (vol->upd_marker)
588 return -EBADF;
589
590 if (len == 0)
591 return 0;
592
593 return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
594}
595EXPORT_SYMBOL_GPL(ubi_leb_change);
596
597/**
598 * ubi_leb_erase - erase logical eraseblock.
599 * @desc: volume descriptor
600 * @lnum: logical eraseblock number
601 *
602 * This function un-maps logical eraseblock @lnum and synchronously erases the
603 * correspondent physical eraseblock. Returns zero in case of success and a
604 * negative error code in case of failure.
605 *
606 * If the volume is damaged because of an interrupted update this function just
607 * returns immediately with %-EBADF code.
608 */
609int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
610{
611 struct ubi_volume *vol = desc->vol;
612 struct ubi_device *ubi = vol->ubi;
613 int err;
614
615 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
616
617 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
618 return -EROFS;
619
620 if (lnum < 0 || lnum >= vol->reserved_pebs)
621 return -EINVAL;
622
623 if (vol->upd_marker)
624 return -EBADF;
625
626 err = ubi_eba_unmap_leb(ubi, vol, lnum);
627 if (err)
628 return err;
629
630 return ubi_wl_flush(ubi, vol->vol_id, lnum);
631}
632EXPORT_SYMBOL_GPL(ubi_leb_erase);
633
634/**
635 * ubi_leb_unmap - un-map logical eraseblock.
636 * @desc: volume descriptor
637 * @lnum: logical eraseblock number
638 *
639 * This function un-maps logical eraseblock @lnum and schedules the
640 * corresponding physical eraseblock for erasure, so that it will eventually be
641 * physically erased in background. This operation is much faster than the
642 * erase operation.
643 *
644 * Unlike erase, the un-map operation does not guarantee that the logical
645 * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
646 * example, if several logical eraseblocks are un-mapped, and an unclean reboot
647 * happens after this, the logical eraseblocks will not necessarily be
648 * un-mapped again when this MTD device is attached. They may actually be
649 * mapped to the same physical eraseblocks again. So, this function has to be
650 * used with care.
651 *
652 * In other words, when un-mapping a logical eraseblock, UBI does not store
653 * any information about this on the flash media, it just marks the logical
654 * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
655 * eraseblock is physically erased, it will be mapped again to the same logical
656 * eraseblock when the MTD device is attached again.
657 *
658 * The main and obvious use-case of this function is when the contents of a
659 * logical eraseblock has to be re-written. Then it is much more efficient to
660 * first un-map it, then write new data, rather than first erase it, then write
661 * new data. Note, once new data has been written to the logical eraseblock,
662 * UBI guarantees that the old contents has gone forever. In other words, if an
663 * unclean reboot happens after the logical eraseblock has been un-mapped and
664 * then written to, it will contain the last written data.
665 *
666 * This function returns zero in case of success and a negative error code in
667 * case of failure. If the volume is damaged because of an interrupted update
668 * this function just returns immediately with %-EBADF code.
669 */
670int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
671{
672 struct ubi_volume *vol = desc->vol;
673 struct ubi_device *ubi = vol->ubi;
674
675 dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
676
677 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
678 return -EROFS;
679
680 if (lnum < 0 || lnum >= vol->reserved_pebs)
681 return -EINVAL;
682
683 if (vol->upd_marker)
684 return -EBADF;
685
686 return ubi_eba_unmap_leb(ubi, vol, lnum);
687}
688EXPORT_SYMBOL_GPL(ubi_leb_unmap);
689
690/**
691 * ubi_leb_map - map logical eraseblock to a physical eraseblock.
692 * @desc: volume descriptor
693 * @lnum: logical eraseblock number
694 *
695 * This function maps an un-mapped logical eraseblock @lnum to a physical
696 * eraseblock. This means, that after a successful invocation of this
697 * function the logical eraseblock @lnum will be empty (contain only %0xFF
698 * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
699 * happens.
700 *
701 * This function returns zero in case of success, %-EBADF if the volume is
702 * damaged because of an interrupted update, %-EBADMSG if the logical
703 * eraseblock is already mapped, and other negative error codes in case of
704 * other failures.
705 */
706int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
707{
708 struct ubi_volume *vol = desc->vol;
709 struct ubi_device *ubi = vol->ubi;
710
711 dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
712
713 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
714 return -EROFS;
715
716 if (lnum < 0 || lnum >= vol->reserved_pebs)
717 return -EINVAL;
718
719 if (vol->upd_marker)
720 return -EBADF;
721
722 if (vol->eba_tbl[lnum] >= 0)
723 return -EBADMSG;
724
725 return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
726}
727EXPORT_SYMBOL_GPL(ubi_leb_map);
728
729/**
730 * ubi_is_mapped - check if logical eraseblock is mapped.
731 * @desc: volume descriptor
732 * @lnum: logical eraseblock number
733 *
734 * This function checks if logical eraseblock @lnum is mapped to a physical
735 * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
736 * mean it will still be un-mapped after the UBI device is re-attached. The
737 * logical eraseblock may become mapped to the physical eraseblock it was last
738 * mapped to.
739 *
740 * This function returns %1 if the LEB is mapped, %0 if not, and a negative
741 * error code in case of failure. If the volume is damaged because of an
742 * interrupted update this function just returns immediately with %-EBADF error
743 * code.
744 */
745int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
746{
747 struct ubi_volume *vol = desc->vol;
748
749 dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
750
751 if (lnum < 0 || lnum >= vol->reserved_pebs)
752 return -EINVAL;
753
754 if (vol->upd_marker)
755 return -EBADF;
756
757 return vol->eba_tbl[lnum] >= 0;
758}
759EXPORT_SYMBOL_GPL(ubi_is_mapped);
760
761/**
762 * ubi_sync - synchronize UBI device buffers.
763 * @ubi_num: UBI device to synchronize
764 *
765 * The underlying MTD device may cache data in hardware or in software. This
766 * function ensures the caches are flushed. Returns zero in case of success and
767 * a negative error code in case of failure.
768 */
769int ubi_sync(int ubi_num)
770{
771 struct ubi_device *ubi;
772
773 ubi = ubi_get_device(ubi_num);
774 if (!ubi)
775 return -ENODEV;
776
777 mtd_sync(ubi->mtd);
778 ubi_put_device(ubi);
779 return 0;
780}
781EXPORT_SYMBOL_GPL(ubi_sync);
782
783/**
784 * ubi_flush - flush UBI work queue.
785 * @ubi_num: UBI device to flush work queue
786 * @vol_id: volume id to flush for
787 * @lnum: logical eraseblock number to flush for
788 *
789 * This function executes all pending works for a particular volume id / logical
790 * eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
791 * a wildcard for all of the corresponding volume numbers or logical
792 * eraseblock numbers. It returns zero in case of success and a negative error
793 * code in case of failure.
794 */
795int ubi_flush(int ubi_num, int vol_id, int lnum)
796{
797 struct ubi_device *ubi;
798 int err = 0;
799
800 ubi = ubi_get_device(ubi_num);
801 if (!ubi)
802 return -ENODEV;
803
804 err = ubi_wl_flush(ubi, vol_id, lnum);
805 ubi_put_device(ubi);
806 return err;
807}
808EXPORT_SYMBOL_GPL(ubi_flush);
809
810BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
811
812/**
813 * ubi_register_volume_notifier - register a volume notifier.
814 * @nb: the notifier description object
815 * @ignore_existing: if non-zero, do not send "added" notification for all
816 * already existing volumes
817 *
818 * This function registers a volume notifier, which means that
819 * 'nb->notifier_call()' will be invoked when an UBI volume is created,
820 * removed, re-sized, re-named, or updated. The first argument of the function
821 * is the notification type. The second argument is pointer to a
822 * &struct ubi_notification object which describes the notification event.
823 * Using UBI API from the volume notifier is prohibited.
824 *
825 * This function returns zero in case of success and a negative error code
826 * in case of failure.
827 */
828int ubi_register_volume_notifier(struct notifier_block *nb,
829 int ignore_existing)
830{
831 int err;
832
833 err = blocking_notifier_chain_register(&ubi_notifiers, nb);
834 if (err != 0)
835 return err;
836 if (ignore_existing)
837 return 0;
838
839 /*
840 * We are going to walk all UBI devices and all volumes, and
841 * notify the user about existing volumes by the %UBI_VOLUME_ADDED
842 * event. We have to lock the @ubi_devices_mutex to make sure UBI
843 * devices do not disappear.
844 */
845 mutex_lock(&ubi_devices_mutex);
846 ubi_enumerate_volumes(nb);
847 mutex_unlock(&ubi_devices_mutex);
848
849 return err;
850}
851EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
852
853/**
854 * ubi_unregister_volume_notifier - unregister the volume notifier.
855 * @nb: the notifier description object
856 *
857 * This function unregisters volume notifier @nm and returns zero in case of
858 * success and a negative error code in case of failure.
859 */
860int ubi_unregister_volume_notifier(struct notifier_block *nb)
861{
862 return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
863}
864EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);