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 */
ubi_do_get_device_info(struct ubi_device * ubi,struct ubi_device_info * di)26 void 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 }
36 EXPORT_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 */
ubi_get_device_info(int ubi_num,struct ubi_device_info * di)46 int 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 }
59 EXPORT_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 */
ubi_do_get_volume_info(struct ubi_device * ubi,struct ubi_volume * vol,struct ubi_volume_info * vi)67 void 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 */
ubi_get_volume_info(struct ubi_volume_desc * desc,struct ubi_volume_info * vi)90 void 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 }
95 EXPORT_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 */
ubi_open_volume(int ubi_num,int vol_id,int mode)115 struct 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 || vol->is_dead)
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
212 out_unlock:
213 spin_unlock(&ubi->volumes_lock);
214 module_put(THIS_MODULE);
215 out_free:
216 kfree(desc);
217 out_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 }
223 EXPORT_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 */
ubi_open_volume_nm(int ubi_num,const char * name,int mode)233 struct 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 }
280 EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
281
282 /**
283 * ubi_get_num_by_path - get UBI device and volume number from device path
284 * @pathname: volume character device node path
285 * @ubi_num: pointer to UBI device number to be set
286 * @vol_id: pointer to UBI volume ID to be set
287 *
288 * Returns 0 on success and sets ubi_num and vol_id, returns error otherwise.
289 */
ubi_get_num_by_path(const char * pathname,int * ubi_num,int * vol_id)290 int ubi_get_num_by_path(const char *pathname, int *ubi_num, int *vol_id)
291 {
292 int error;
293 struct path path;
294 struct kstat stat;
295
296 error = kern_path(pathname, LOOKUP_FOLLOW, &path);
297 if (error)
298 return error;
299
300 error = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
301 path_put(&path);
302 if (error)
303 return error;
304
305 if (!S_ISCHR(stat.mode))
306 return -EINVAL;
307
308 *ubi_num = ubi_major2num(MAJOR(stat.rdev));
309 *vol_id = MINOR(stat.rdev) - 1;
310
311 if (*vol_id < 0 || *ubi_num < 0)
312 return -ENODEV;
313
314 return 0;
315 }
316
317 /**
318 * ubi_open_volume_path - open UBI volume by its character device node path.
319 * @pathname: volume character device node path
320 * @mode: open mode
321 *
322 * This function is similar to 'ubi_open_volume()', but opens a volume the path
323 * to its character device node.
324 */
ubi_open_volume_path(const char * pathname,int mode)325 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
326 {
327 int error, ubi_num, vol_id;
328
329 dbg_gen("open volume %s, mode %d", pathname, mode);
330
331 if (!pathname || !*pathname)
332 return ERR_PTR(-EINVAL);
333
334 error = ubi_get_num_by_path(pathname, &ubi_num, &vol_id);
335 if (error)
336 return ERR_PTR(error);
337
338 return ubi_open_volume(ubi_num, vol_id, mode);
339 }
340 EXPORT_SYMBOL_GPL(ubi_open_volume_path);
341
342 /**
343 * ubi_close_volume - close UBI volume.
344 * @desc: volume descriptor
345 */
ubi_close_volume(struct ubi_volume_desc * desc)346 void ubi_close_volume(struct ubi_volume_desc *desc)
347 {
348 struct ubi_volume *vol = desc->vol;
349 struct ubi_device *ubi = vol->ubi;
350
351 dbg_gen("close device %d, volume %d, mode %d",
352 ubi->ubi_num, vol->vol_id, desc->mode);
353
354 spin_lock(&ubi->volumes_lock);
355 switch (desc->mode) {
356 case UBI_READONLY:
357 vol->readers -= 1;
358 break;
359 case UBI_READWRITE:
360 vol->writers -= 1;
361 break;
362 case UBI_EXCLUSIVE:
363 vol->exclusive = 0;
364 break;
365 case UBI_METAONLY:
366 vol->metaonly = 0;
367 break;
368 }
369 vol->ref_count -= 1;
370 spin_unlock(&ubi->volumes_lock);
371
372 kfree(desc);
373 put_device(&vol->dev);
374 ubi_put_device(ubi);
375 module_put(THIS_MODULE);
376 }
377 EXPORT_SYMBOL_GPL(ubi_close_volume);
378
379 /**
380 * leb_read_sanity_check - does sanity checks on read requests.
381 * @desc: volume descriptor
382 * @lnum: logical eraseblock number to read from
383 * @offset: offset within the logical eraseblock to read from
384 * @len: how many bytes to read
385 *
386 * This function is used by ubi_leb_read() and ubi_leb_read_sg()
387 * to perform sanity checks.
388 */
leb_read_sanity_check(struct ubi_volume_desc * desc,int lnum,int offset,int len)389 static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
390 int offset, int len)
391 {
392 struct ubi_volume *vol = desc->vol;
393 struct ubi_device *ubi = vol->ubi;
394 int vol_id = vol->vol_id;
395
396 if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
397 lnum >= vol->used_ebs || offset < 0 || len < 0 ||
398 offset + len > vol->usable_leb_size)
399 return -EINVAL;
400
401 if (vol->vol_type == UBI_STATIC_VOLUME) {
402 if (vol->used_ebs == 0)
403 /* Empty static UBI volume */
404 return 0;
405 if (lnum == vol->used_ebs - 1 &&
406 offset + len > vol->last_eb_bytes)
407 return -EINVAL;
408 }
409
410 if (vol->upd_marker)
411 return -EBADF;
412
413 return 0;
414 }
415
416 /**
417 * ubi_leb_read - read data.
418 * @desc: volume descriptor
419 * @lnum: logical eraseblock number to read from
420 * @buf: buffer where to store the read data
421 * @offset: offset within the logical eraseblock to read from
422 * @len: how many bytes to read
423 * @check: whether UBI has to check the read data's CRC or not.
424 *
425 * This function reads data from offset @offset of logical eraseblock @lnum and
426 * stores the data at @buf. When reading from static volumes, @check specifies
427 * whether the data has to be checked or not. If yes, the whole logical
428 * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
429 * checksum is per-eraseblock). So checking may substantially slow down the
430 * read speed. The @check argument is ignored for dynamic volumes.
431 *
432 * In case of success, this function returns zero. In case of failure, this
433 * function returns a negative error code.
434 *
435 * %-EBADMSG error code is returned:
436 * o for both static and dynamic volumes if MTD driver has detected a data
437 * integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
438 * o for static volumes in case of data CRC mismatch.
439 *
440 * If the volume is damaged because of an interrupted update this function just
441 * returns immediately with %-EBADF error code.
442 */
ubi_leb_read(struct ubi_volume_desc * desc,int lnum,char * buf,int offset,int len,int check)443 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
444 int len, int check)
445 {
446 struct ubi_volume *vol = desc->vol;
447 struct ubi_device *ubi = vol->ubi;
448 int err, vol_id = vol->vol_id;
449
450 dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
451
452 err = leb_read_sanity_check(desc, lnum, offset, len);
453 if (err < 0)
454 return err;
455
456 if (len == 0)
457 return 0;
458
459 err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
460 if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
461 ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
462 vol->corrupted = 1;
463 }
464
465 return err;
466 }
467 EXPORT_SYMBOL_GPL(ubi_leb_read);
468
469
470 /**
471 * ubi_leb_read_sg - read data into a scatter gather list.
472 * @desc: volume descriptor
473 * @lnum: logical eraseblock number to read from
474 * @sgl: UBI scatter gather list to store the read data
475 * @offset: offset within the logical eraseblock to read from
476 * @len: how many bytes to read
477 * @check: whether UBI has to check the read data's CRC or not.
478 *
479 * This function works exactly like ubi_leb_read_sg(). But instead of
480 * storing the read data into a buffer it writes to an UBI scatter gather
481 * list.
482 */
ubi_leb_read_sg(struct ubi_volume_desc * desc,int lnum,struct ubi_sgl * sgl,int offset,int len,int check)483 int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
484 int offset, int len, int check)
485 {
486 struct ubi_volume *vol = desc->vol;
487 struct ubi_device *ubi = vol->ubi;
488 int err, vol_id = vol->vol_id;
489
490 dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
491
492 err = leb_read_sanity_check(desc, lnum, offset, len);
493 if (err < 0)
494 return err;
495
496 if (len == 0)
497 return 0;
498
499 err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
500 if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
501 ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
502 vol->corrupted = 1;
503 }
504
505 return err;
506 }
507 EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
508
509 /**
510 * ubi_leb_write - write data.
511 * @desc: volume descriptor
512 * @lnum: logical eraseblock number to write to
513 * @buf: data to write
514 * @offset: offset within the logical eraseblock where to write
515 * @len: how many bytes to write
516 *
517 * This function writes @len bytes of data from @buf to offset @offset of
518 * logical eraseblock @lnum.
519 *
520 * This function takes care of physical eraseblock write failures. If write to
521 * the physical eraseblock write operation fails, the logical eraseblock is
522 * re-mapped to another physical eraseblock, the data is recovered, and the
523 * write finishes. UBI has a pool of reserved physical eraseblocks for this.
524 *
525 * If all the data were successfully written, zero is returned. If an error
526 * occurred and UBI has not been able to recover from it, this function returns
527 * a negative error code. Note, in case of an error, it is possible that
528 * something was still written to the flash media, but that may be some
529 * garbage.
530 *
531 * If the volume is damaged because of an interrupted update this function just
532 * returns immediately with %-EBADF code.
533 */
ubi_leb_write(struct ubi_volume_desc * desc,int lnum,const void * buf,int offset,int len)534 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
535 int offset, int len)
536 {
537 struct ubi_volume *vol = desc->vol;
538 struct ubi_device *ubi = vol->ubi;
539 int vol_id = vol->vol_id;
540
541 dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
542
543 if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
544 return -EINVAL;
545
546 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
547 return -EROFS;
548
549 if (!ubi_leb_valid(vol, lnum) || offset < 0 || len < 0 ||
550 offset + len > vol->usable_leb_size ||
551 offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
552 return -EINVAL;
553
554 if (vol->upd_marker)
555 return -EBADF;
556
557 if (len == 0)
558 return 0;
559
560 return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
561 }
562 EXPORT_SYMBOL_GPL(ubi_leb_write);
563
564 /*
565 * ubi_leb_change - change logical eraseblock atomically.
566 * @desc: volume descriptor
567 * @lnum: logical eraseblock number to change
568 * @buf: data to write
569 * @len: how many bytes to write
570 *
571 * This function changes the contents of a logical eraseblock atomically. @buf
572 * has to contain new logical eraseblock data, and @len - the length of the
573 * data, which has to be aligned. The length may be shorter than the logical
574 * eraseblock size, ant the logical eraseblock may be appended to more times
575 * later on. This function guarantees that in case of an unclean reboot the old
576 * contents is preserved. Returns zero in case of success and a negative error
577 * code in case of failure.
578 */
ubi_leb_change(struct ubi_volume_desc * desc,int lnum,const void * buf,int len)579 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
580 int len)
581 {
582 struct ubi_volume *vol = desc->vol;
583 struct ubi_device *ubi = vol->ubi;
584 int vol_id = vol->vol_id;
585
586 dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
587
588 if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
589 return -EINVAL;
590
591 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
592 return -EROFS;
593
594 if (!ubi_leb_valid(vol, lnum) || len < 0 ||
595 len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
596 return -EINVAL;
597
598 if (vol->upd_marker)
599 return -EBADF;
600
601 if (len == 0)
602 return 0;
603
604 return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
605 }
606 EXPORT_SYMBOL_GPL(ubi_leb_change);
607
608 /**
609 * ubi_leb_erase - erase logical eraseblock.
610 * @desc: volume descriptor
611 * @lnum: logical eraseblock number
612 *
613 * This function un-maps logical eraseblock @lnum and synchronously erases the
614 * correspondent physical eraseblock. Returns zero in case of success and a
615 * negative error code in case of failure.
616 *
617 * If the volume is damaged because of an interrupted update this function just
618 * returns immediately with %-EBADF code.
619 */
ubi_leb_erase(struct ubi_volume_desc * desc,int lnum)620 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
621 {
622 struct ubi_volume *vol = desc->vol;
623 struct ubi_device *ubi = vol->ubi;
624 int err;
625
626 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
627
628 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
629 return -EROFS;
630
631 if (!ubi_leb_valid(vol, lnum))
632 return -EINVAL;
633
634 if (vol->upd_marker)
635 return -EBADF;
636
637 err = ubi_eba_unmap_leb(ubi, vol, lnum);
638 if (err)
639 return err;
640
641 return ubi_wl_flush(ubi, vol->vol_id, lnum);
642 }
643 EXPORT_SYMBOL_GPL(ubi_leb_erase);
644
645 /**
646 * ubi_leb_unmap - un-map logical eraseblock.
647 * @desc: volume descriptor
648 * @lnum: logical eraseblock number
649 *
650 * This function un-maps logical eraseblock @lnum and schedules the
651 * corresponding physical eraseblock for erasure, so that it will eventually be
652 * physically erased in background. This operation is much faster than the
653 * erase operation.
654 *
655 * Unlike erase, the un-map operation does not guarantee that the logical
656 * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
657 * example, if several logical eraseblocks are un-mapped, and an unclean reboot
658 * happens after this, the logical eraseblocks will not necessarily be
659 * un-mapped again when this MTD device is attached. They may actually be
660 * mapped to the same physical eraseblocks again. So, this function has to be
661 * used with care.
662 *
663 * In other words, when un-mapping a logical eraseblock, UBI does not store
664 * any information about this on the flash media, it just marks the logical
665 * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
666 * eraseblock is physically erased, it will be mapped again to the same logical
667 * eraseblock when the MTD device is attached again.
668 *
669 * The main and obvious use-case of this function is when the contents of a
670 * logical eraseblock has to be re-written. Then it is much more efficient to
671 * first un-map it, then write new data, rather than first erase it, then write
672 * new data. Note, once new data has been written to the logical eraseblock,
673 * UBI guarantees that the old contents has gone forever. In other words, if an
674 * unclean reboot happens after the logical eraseblock has been un-mapped and
675 * then written to, it will contain the last written data.
676 *
677 * This function returns zero in case of success and a negative error code in
678 * case of failure. If the volume is damaged because of an interrupted update
679 * this function just returns immediately with %-EBADF code.
680 */
ubi_leb_unmap(struct ubi_volume_desc * desc,int lnum)681 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
682 {
683 struct ubi_volume *vol = desc->vol;
684 struct ubi_device *ubi = vol->ubi;
685
686 dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
687
688 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
689 return -EROFS;
690
691 if (!ubi_leb_valid(vol, lnum))
692 return -EINVAL;
693
694 if (vol->upd_marker)
695 return -EBADF;
696
697 return ubi_eba_unmap_leb(ubi, vol, lnum);
698 }
699 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
700
701 /**
702 * ubi_leb_map - map logical eraseblock to a physical eraseblock.
703 * @desc: volume descriptor
704 * @lnum: logical eraseblock number
705 *
706 * This function maps an un-mapped logical eraseblock @lnum to a physical
707 * eraseblock. This means, that after a successful invocation of this
708 * function the logical eraseblock @lnum will be empty (contain only %0xFF
709 * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
710 * happens.
711 *
712 * This function returns zero in case of success, %-EBADF if the volume is
713 * damaged because of an interrupted update, %-EBADMSG if the logical
714 * eraseblock is already mapped, and other negative error codes in case of
715 * other failures.
716 */
ubi_leb_map(struct ubi_volume_desc * desc,int lnum)717 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
718 {
719 struct ubi_volume *vol = desc->vol;
720 struct ubi_device *ubi = vol->ubi;
721
722 dbg_gen("map LEB %d:%d", vol->vol_id, lnum);
723
724 if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
725 return -EROFS;
726
727 if (!ubi_leb_valid(vol, lnum))
728 return -EINVAL;
729
730 if (vol->upd_marker)
731 return -EBADF;
732
733 if (ubi_eba_is_mapped(vol, lnum))
734 return -EBADMSG;
735
736 return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
737 }
738 EXPORT_SYMBOL_GPL(ubi_leb_map);
739
740 /**
741 * ubi_is_mapped - check if logical eraseblock is mapped.
742 * @desc: volume descriptor
743 * @lnum: logical eraseblock number
744 *
745 * This function checks if logical eraseblock @lnum is mapped to a physical
746 * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
747 * mean it will still be un-mapped after the UBI device is re-attached. The
748 * logical eraseblock may become mapped to the physical eraseblock it was last
749 * mapped to.
750 *
751 * This function returns %1 if the LEB is mapped, %0 if not, and a negative
752 * error code in case of failure. If the volume is damaged because of an
753 * interrupted update this function just returns immediately with %-EBADF error
754 * code.
755 */
ubi_is_mapped(struct ubi_volume_desc * desc,int lnum)756 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
757 {
758 struct ubi_volume *vol = desc->vol;
759
760 dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
761
762 if (!ubi_leb_valid(vol, lnum))
763 return -EINVAL;
764
765 if (vol->upd_marker)
766 return -EBADF;
767
768 return ubi_eba_is_mapped(vol, lnum);
769 }
770 EXPORT_SYMBOL_GPL(ubi_is_mapped);
771
772 /**
773 * ubi_sync - synchronize UBI device buffers.
774 * @ubi_num: UBI device to synchronize
775 *
776 * The underlying MTD device may cache data in hardware or in software. This
777 * function ensures the caches are flushed. Returns zero in case of success and
778 * a negative error code in case of failure.
779 */
ubi_sync(int ubi_num)780 int ubi_sync(int ubi_num)
781 {
782 struct ubi_device *ubi;
783
784 ubi = ubi_get_device(ubi_num);
785 if (!ubi)
786 return -ENODEV;
787
788 mtd_sync(ubi->mtd);
789 ubi_put_device(ubi);
790 return 0;
791 }
792 EXPORT_SYMBOL_GPL(ubi_sync);
793
794 /**
795 * ubi_flush - flush UBI work queue.
796 * @ubi_num: UBI device to flush work queue
797 * @vol_id: volume id to flush for
798 * @lnum: logical eraseblock number to flush for
799 *
800 * This function executes all pending works for a particular volume id / logical
801 * eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
802 * a wildcard for all of the corresponding volume numbers or logical
803 * eraseblock numbers. It returns zero in case of success and a negative error
804 * code in case of failure.
805 */
ubi_flush(int ubi_num,int vol_id,int lnum)806 int ubi_flush(int ubi_num, int vol_id, int lnum)
807 {
808 struct ubi_device *ubi;
809 int err = 0;
810
811 ubi = ubi_get_device(ubi_num);
812 if (!ubi)
813 return -ENODEV;
814
815 err = ubi_wl_flush(ubi, vol_id, lnum);
816 ubi_put_device(ubi);
817 return err;
818 }
819 EXPORT_SYMBOL_GPL(ubi_flush);
820
821 BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
822
823 /**
824 * ubi_register_volume_notifier - register a volume notifier.
825 * @nb: the notifier description object
826 * @ignore_existing: if non-zero, do not send "added" notification for all
827 * already existing volumes
828 *
829 * This function registers a volume notifier, which means that
830 * 'nb->notifier_call()' will be invoked when an UBI volume is created,
831 * removed, re-sized, re-named, or updated. The first argument of the function
832 * is the notification type. The second argument is pointer to a
833 * &struct ubi_notification object which describes the notification event.
834 * Using UBI API from the volume notifier is prohibited.
835 *
836 * This function returns zero in case of success and a negative error code
837 * in case of failure.
838 */
ubi_register_volume_notifier(struct notifier_block * nb,int ignore_existing)839 int ubi_register_volume_notifier(struct notifier_block *nb,
840 int ignore_existing)
841 {
842 int err;
843
844 err = blocking_notifier_chain_register(&ubi_notifiers, nb);
845 if (err != 0)
846 return err;
847 if (ignore_existing)
848 return 0;
849
850 /*
851 * We are going to walk all UBI devices and all volumes, and
852 * notify the user about existing volumes by the %UBI_VOLUME_ADDED
853 * event. We have to lock the @ubi_devices_mutex to make sure UBI
854 * devices do not disappear.
855 */
856 mutex_lock(&ubi_devices_mutex);
857 ubi_enumerate_volumes(nb);
858 mutex_unlock(&ubi_devices_mutex);
859
860 return err;
861 }
862 EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
863
864 /**
865 * ubi_unregister_volume_notifier - unregister the volume notifier.
866 * @nb: the notifier description object
867 *
868 * This function unregisters volume notifier @nm and returns zero in case of
869 * success and a negative error code in case of failure.
870 */
ubi_unregister_volume_notifier(struct notifier_block * nb)871 int ubi_unregister_volume_notifier(struct notifier_block *nb)
872 {
873 return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
874 }
875 EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);
876