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/*
9 * The UBI Eraseblock Association (EBA) sub-system.
10 *
11 * This sub-system is responsible for I/O to/from logical eraseblock.
12 *
13 * Although in this implementation the EBA table is fully kept and managed in
14 * RAM, which assumes poor scalability, it might be (partially) maintained on
15 * flash in future implementations.
16 *
17 * The EBA sub-system implements per-logical eraseblock locking. Before
18 * accessing a logical eraseblock it is locked for reading or writing. The
19 * per-logical eraseblock locking is implemented by means of the lock tree. The
20 * lock tree is an RB-tree which refers all the currently locked logical
21 * eraseblocks. The lock tree elements are &struct ubi_ltree_entry objects.
22 * They are indexed by (@vol_id, @lnum) pairs.
23 *
24 * EBA also maintains the global sequence counter which is incremented each
25 * time a logical eraseblock is mapped to a physical eraseblock and it is
26 * stored in the volume identifier header. This means that each VID header has
27 * a unique sequence number. The sequence number is only increased an we assume
28 * 64 bits is enough to never overflow.
29 */
30
31#include <linux/slab.h>
32#include <linux/crc32.h>
33#include <linux/err.h>
34#include "ubi.h"
35
36/**
37 * struct ubi_eba_entry - structure encoding a single LEB -> PEB association
38 * @pnum: the physical eraseblock number attached to the LEB
39 *
40 * This structure is encoding a LEB -> PEB association. Note that the LEB
41 * number is not stored here, because it is the index used to access the
42 * entries table.
43 */
44struct ubi_eba_entry {
45 int pnum;
46};
47
48/**
49 * struct ubi_eba_table - LEB -> PEB association information
50 * @entries: the LEB to PEB mapping (one entry per LEB).
51 *
52 * This structure is private to the EBA logic and should be kept here.
53 * It is encoding the LEB to PEB association table, and is subject to
54 * changes.
55 */
56struct ubi_eba_table {
57 struct ubi_eba_entry *entries;
58};
59
60/**
61 * ubi_next_sqnum - get next sequence number.
62 * @ubi: UBI device description object
63 *
64 * This function returns next sequence number to use, which is just the current
65 * global sequence counter value. It also increases the global sequence
66 * counter.
67 */
68unsigned long long ubi_next_sqnum(struct ubi_device *ubi)
69{
70 unsigned long long sqnum;
71
72 spin_lock(lock: &ubi->ltree_lock);
73 sqnum = ubi->global_sqnum++;
74 spin_unlock(lock: &ubi->ltree_lock);
75
76 return sqnum;
77}
78
79/**
80 * ubi_get_compat - get compatibility flags of a volume.
81 * @ubi: UBI device description object
82 * @vol_id: volume ID
83 *
84 * This function returns compatibility flags for an internal volume. User
85 * volumes have no compatibility flags, so %0 is returned.
86 */
87static int ubi_get_compat(const struct ubi_device *ubi, int vol_id)
88{
89 if (vol_id == UBI_LAYOUT_VOLUME_ID)
90 return UBI_LAYOUT_VOLUME_COMPAT;
91 return 0;
92}
93
94/**
95 * ubi_eba_get_ldesc - get information about a LEB
96 * @vol: volume description object
97 * @lnum: logical eraseblock number
98 * @ldesc: the LEB descriptor to fill
99 *
100 * Used to query information about a specific LEB.
101 * It is currently only returning the physical position of the LEB, but will be
102 * extended to provide more information.
103 */
104void ubi_eba_get_ldesc(struct ubi_volume *vol, int lnum,
105 struct ubi_eba_leb_desc *ldesc)
106{
107 ldesc->lnum = lnum;
108 ldesc->pnum = vol->eba_tbl->entries[lnum].pnum;
109}
110
111/**
112 * ubi_eba_create_table - allocate a new EBA table and initialize it with all
113 * LEBs unmapped
114 * @vol: volume containing the EBA table to copy
115 * @nentries: number of entries in the table
116 *
117 * Allocate a new EBA table and initialize it with all LEBs unmapped.
118 * Returns a valid pointer if it succeed, an ERR_PTR() otherwise.
119 */
120struct ubi_eba_table *ubi_eba_create_table(struct ubi_volume *vol,
121 int nentries)
122{
123 struct ubi_eba_table *tbl;
124 int err = -ENOMEM;
125 int i;
126
127 tbl = kzalloc(sizeof(*tbl), GFP_KERNEL);
128 if (!tbl)
129 return ERR_PTR(error: -ENOMEM);
130
131 tbl->entries = kmalloc_array(nentries, sizeof(*tbl->entries),
132 GFP_KERNEL);
133 if (!tbl->entries)
134 goto err;
135
136 for (i = 0; i < nentries; i++)
137 tbl->entries[i].pnum = UBI_LEB_UNMAPPED;
138
139 return tbl;
140
141err:
142 kfree(objp: tbl);
143
144 return ERR_PTR(error: err);
145}
146
147/**
148 * ubi_eba_destroy_table - destroy an EBA table
149 * @tbl: the table to destroy
150 *
151 * Destroy an EBA table.
152 */
153void ubi_eba_destroy_table(struct ubi_eba_table *tbl)
154{
155 if (!tbl)
156 return;
157
158 kfree(objp: tbl->entries);
159 kfree(objp: tbl);
160}
161
162/**
163 * ubi_eba_copy_table - copy the EBA table attached to vol into another table
164 * @vol: volume containing the EBA table to copy
165 * @dst: destination
166 * @nentries: number of entries to copy
167 *
168 * Copy the EBA table stored in vol into the one pointed by dst.
169 */
170void ubi_eba_copy_table(struct ubi_volume *vol, struct ubi_eba_table *dst,
171 int nentries)
172{
173 struct ubi_eba_table *src;
174 int i;
175
176 ubi_assert(dst && vol && vol->eba_tbl);
177
178 src = vol->eba_tbl;
179
180 for (i = 0; i < nentries; i++)
181 dst->entries[i].pnum = src->entries[i].pnum;
182}
183
184/**
185 * ubi_eba_replace_table - assign a new EBA table to a volume
186 * @vol: volume containing the EBA table to copy
187 * @tbl: new EBA table
188 *
189 * Assign a new EBA table to the volume and release the old one.
190 */
191void ubi_eba_replace_table(struct ubi_volume *vol, struct ubi_eba_table *tbl)
192{
193 ubi_eba_destroy_table(tbl: vol->eba_tbl);
194 vol->eba_tbl = tbl;
195}
196
197/**
198 * ltree_lookup - look up the lock tree.
199 * @ubi: UBI device description object
200 * @vol_id: volume ID
201 * @lnum: logical eraseblock number
202 *
203 * This function returns a pointer to the corresponding &struct ubi_ltree_entry
204 * object if the logical eraseblock is locked and %NULL if it is not.
205 * @ubi->ltree_lock has to be locked.
206 */
207static struct ubi_ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id,
208 int lnum)
209{
210 struct rb_node *p;
211
212 p = ubi->ltree.rb_node;
213 while (p) {
214 struct ubi_ltree_entry *le;
215
216 le = rb_entry(p, struct ubi_ltree_entry, rb);
217
218 if (vol_id < le->vol_id)
219 p = p->rb_left;
220 else if (vol_id > le->vol_id)
221 p = p->rb_right;
222 else {
223 if (lnum < le->lnum)
224 p = p->rb_left;
225 else if (lnum > le->lnum)
226 p = p->rb_right;
227 else
228 return le;
229 }
230 }
231
232 return NULL;
233}
234
235/**
236 * ltree_add_entry - add new entry to the lock tree.
237 * @ubi: UBI device description object
238 * @vol_id: volume ID
239 * @lnum: logical eraseblock number
240 *
241 * This function adds new entry for logical eraseblock (@vol_id, @lnum) to the
242 * lock tree. If such entry is already there, its usage counter is increased.
243 * Returns pointer to the lock tree entry or %-ENOMEM if memory allocation
244 * failed.
245 */
246static struct ubi_ltree_entry *ltree_add_entry(struct ubi_device *ubi,
247 int vol_id, int lnum)
248{
249 struct ubi_ltree_entry *le, *le1, *le_free;
250
251 le = kmalloc(sizeof(struct ubi_ltree_entry), GFP_NOFS);
252 if (!le)
253 return ERR_PTR(error: -ENOMEM);
254
255 le->users = 0;
256 init_rwsem(&le->mutex);
257 le->vol_id = vol_id;
258 le->lnum = lnum;
259
260 spin_lock(lock: &ubi->ltree_lock);
261 le1 = ltree_lookup(ubi, vol_id, lnum);
262
263 if (le1) {
264 /*
265 * This logical eraseblock is already locked. The newly
266 * allocated lock entry is not needed.
267 */
268 le_free = le;
269 le = le1;
270 } else {
271 struct rb_node **p, *parent = NULL;
272
273 /*
274 * No lock entry, add the newly allocated one to the
275 * @ubi->ltree RB-tree.
276 */
277 le_free = NULL;
278
279 p = &ubi->ltree.rb_node;
280 while (*p) {
281 parent = *p;
282 le1 = rb_entry(parent, struct ubi_ltree_entry, rb);
283
284 if (vol_id < le1->vol_id)
285 p = &(*p)->rb_left;
286 else if (vol_id > le1->vol_id)
287 p = &(*p)->rb_right;
288 else {
289 ubi_assert(lnum != le1->lnum);
290 if (lnum < le1->lnum)
291 p = &(*p)->rb_left;
292 else
293 p = &(*p)->rb_right;
294 }
295 }
296
297 rb_link_node(node: &le->rb, parent, rb_link: p);
298 rb_insert_color(&le->rb, &ubi->ltree);
299 }
300 le->users += 1;
301 spin_unlock(lock: &ubi->ltree_lock);
302
303 kfree(objp: le_free);
304 return le;
305}
306
307/**
308 * leb_read_lock - lock logical eraseblock for reading.
309 * @ubi: UBI device description object
310 * @vol_id: volume ID
311 * @lnum: logical eraseblock number
312 *
313 * This function locks a logical eraseblock for reading. Returns zero in case
314 * of success and a negative error code in case of failure.
315 */
316static int leb_read_lock(struct ubi_device *ubi, int vol_id, int lnum)
317{
318 struct ubi_ltree_entry *le;
319
320 le = ltree_add_entry(ubi, vol_id, lnum);
321 if (IS_ERR(ptr: le))
322 return PTR_ERR(ptr: le);
323 down_read(sem: &le->mutex);
324 return 0;
325}
326
327/**
328 * leb_read_unlock - unlock logical eraseblock.
329 * @ubi: UBI device description object
330 * @vol_id: volume ID
331 * @lnum: logical eraseblock number
332 */
333static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum)
334{
335 struct ubi_ltree_entry *le;
336
337 spin_lock(lock: &ubi->ltree_lock);
338 le = ltree_lookup(ubi, vol_id, lnum);
339 le->users -= 1;
340 ubi_assert(le->users >= 0);
341 up_read(sem: &le->mutex);
342 if (le->users == 0) {
343 rb_erase(&le->rb, &ubi->ltree);
344 kfree(objp: le);
345 }
346 spin_unlock(lock: &ubi->ltree_lock);
347}
348
349/**
350 * leb_write_lock - lock logical eraseblock for writing.
351 * @ubi: UBI device description object
352 * @vol_id: volume ID
353 * @lnum: logical eraseblock number
354 *
355 * This function locks a logical eraseblock for writing. Returns zero in case
356 * of success and a negative error code in case of failure.
357 */
358static int leb_write_lock(struct ubi_device *ubi, int vol_id, int lnum)
359{
360 struct ubi_ltree_entry *le;
361
362 le = ltree_add_entry(ubi, vol_id, lnum);
363 if (IS_ERR(ptr: le))
364 return PTR_ERR(ptr: le);
365 down_write(sem: &le->mutex);
366 return 0;
367}
368
369/**
370 * leb_write_trylock - try to lock logical eraseblock for writing.
371 * @ubi: UBI device description object
372 * @vol_id: volume ID
373 * @lnum: logical eraseblock number
374 *
375 * This function locks a logical eraseblock for writing if there is no
376 * contention and does nothing if there is contention. Returns %0 in case of
377 * success, %1 in case of contention, and a negative error code in case of
378 * failure.
379 */
380static int leb_write_trylock(struct ubi_device *ubi, int vol_id, int lnum)
381{
382 struct ubi_ltree_entry *le;
383
384 le = ltree_add_entry(ubi, vol_id, lnum);
385 if (IS_ERR(ptr: le))
386 return PTR_ERR(ptr: le);
387 if (down_write_trylock(sem: &le->mutex))
388 return 0;
389
390 /* Contention, cancel */
391 spin_lock(lock: &ubi->ltree_lock);
392 le->users -= 1;
393 ubi_assert(le->users >= 0);
394 if (le->users == 0) {
395 rb_erase(&le->rb, &ubi->ltree);
396 kfree(objp: le);
397 }
398 spin_unlock(lock: &ubi->ltree_lock);
399
400 return 1;
401}
402
403/**
404 * leb_write_unlock - unlock logical eraseblock.
405 * @ubi: UBI device description object
406 * @vol_id: volume ID
407 * @lnum: logical eraseblock number
408 */
409static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
410{
411 struct ubi_ltree_entry *le;
412
413 spin_lock(lock: &ubi->ltree_lock);
414 le = ltree_lookup(ubi, vol_id, lnum);
415 le->users -= 1;
416 ubi_assert(le->users >= 0);
417 up_write(sem: &le->mutex);
418 if (le->users == 0) {
419 rb_erase(&le->rb, &ubi->ltree);
420 kfree(objp: le);
421 }
422 spin_unlock(lock: &ubi->ltree_lock);
423}
424
425/**
426 * ubi_eba_is_mapped - check if a LEB is mapped.
427 * @vol: volume description object
428 * @lnum: logical eraseblock number
429 *
430 * This function returns true if the LEB is mapped, false otherwise.
431 */
432bool ubi_eba_is_mapped(struct ubi_volume *vol, int lnum)
433{
434 return vol->eba_tbl->entries[lnum].pnum >= 0;
435}
436
437/**
438 * ubi_eba_unmap_leb - un-map logical eraseblock.
439 * @ubi: UBI device description object
440 * @vol: volume description object
441 * @lnum: logical eraseblock number
442 *
443 * This function un-maps logical eraseblock @lnum and schedules corresponding
444 * physical eraseblock for erasure. Returns zero in case of success and a
445 * negative error code in case of failure.
446 */
447int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
448 int lnum)
449{
450 int err, pnum, vol_id = vol->vol_id;
451
452 if (ubi->ro_mode)
453 return -EROFS;
454
455 err = leb_write_lock(ubi, vol_id, lnum);
456 if (err)
457 return err;
458
459 pnum = vol->eba_tbl->entries[lnum].pnum;
460 if (pnum < 0)
461 /* This logical eraseblock is already unmapped */
462 goto out_unlock;
463
464 dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum);
465
466 down_read(sem: &ubi->fm_eba_sem);
467 vol->eba_tbl->entries[lnum].pnum = UBI_LEB_UNMAPPED;
468 up_read(sem: &ubi->fm_eba_sem);
469 err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, torture: 0);
470
471out_unlock:
472 leb_write_unlock(ubi, vol_id, lnum);
473 return err;
474}
475
476#ifdef CONFIG_MTD_UBI_FASTMAP
477/**
478 * check_mapping - check and fixup a mapping
479 * @ubi: UBI device description object
480 * @vol: volume description object
481 * @lnum: logical eraseblock number
482 * @pnum: physical eraseblock number
483 *
484 * Checks whether a given mapping is valid. Fastmap cannot track LEB unmap
485 * operations, if such an operation is interrupted the mapping still looks
486 * good, but upon first read an ECC is reported to the upper layer.
487 * Normaly during the full-scan at attach time this is fixed, for Fastmap
488 * we have to deal with it while reading.
489 * If the PEB behind a LEB shows this symthom we change the mapping to
490 * %UBI_LEB_UNMAPPED and schedule the PEB for erasure.
491 *
492 * Returns 0 on success, negative error code in case of failure.
493 */
494static int check_mapping(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
495 int *pnum)
496{
497 int err;
498 struct ubi_vid_io_buf *vidb;
499 struct ubi_vid_hdr *vid_hdr;
500
501 if (!ubi->fast_attach)
502 return 0;
503
504 if (!vol->checkmap || test_bit(lnum, vol->checkmap))
505 return 0;
506
507 vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
508 if (!vidb)
509 return -ENOMEM;
510
511 err = ubi_io_read_vid_hdr(ubi, pnum: *pnum, vidb, verbose: 0);
512 if (err > 0 && err != UBI_IO_BITFLIPS) {
513 int torture = 0;
514
515 switch (err) {
516 case UBI_IO_FF:
517 case UBI_IO_FF_BITFLIPS:
518 case UBI_IO_BAD_HDR:
519 case UBI_IO_BAD_HDR_EBADMSG:
520 break;
521 default:
522 ubi_assert(0);
523 }
524
525 if (err == UBI_IO_BAD_HDR_EBADMSG || err == UBI_IO_FF_BITFLIPS)
526 torture = 1;
527
528 down_read(sem: &ubi->fm_eba_sem);
529 vol->eba_tbl->entries[lnum].pnum = UBI_LEB_UNMAPPED;
530 up_read(sem: &ubi->fm_eba_sem);
531 ubi_wl_put_peb(ubi, vol_id: vol->vol_id, lnum, pnum: *pnum, torture);
532
533 *pnum = UBI_LEB_UNMAPPED;
534 } else if (err < 0) {
535 ubi_err(ubi, fmt: "unable to read VID header back from PEB %i: %i",
536 *pnum, err);
537
538 goto out_free;
539 } else {
540 int found_vol_id, found_lnum;
541
542 ubi_assert(err == 0 || err == UBI_IO_BITFLIPS);
543
544 vid_hdr = ubi_get_vid_hdr(vidb);
545 found_vol_id = be32_to_cpu(vid_hdr->vol_id);
546 found_lnum = be32_to_cpu(vid_hdr->lnum);
547
548 if (found_lnum != lnum || found_vol_id != vol->vol_id) {
549 ubi_err(ubi, fmt: "EBA mismatch! PEB %i is LEB %i:%i instead of LEB %i:%i",
550 *pnum, found_vol_id, found_lnum, vol->vol_id, lnum);
551 ubi_ro_mode(ubi);
552 err = -EINVAL;
553 goto out_free;
554 }
555 }
556
557 set_bit(nr: lnum, addr: vol->checkmap);
558 err = 0;
559
560out_free:
561 ubi_free_vid_buf(vidb);
562
563 return err;
564}
565#else
566static int check_mapping(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
567 int *pnum)
568{
569 return 0;
570}
571#endif
572
573/**
574 * ubi_eba_read_leb - read data.
575 * @ubi: UBI device description object
576 * @vol: volume description object
577 * @lnum: logical eraseblock number
578 * @buf: buffer to store the read data
579 * @offset: offset from where to read
580 * @len: how many bytes to read
581 * @check: data CRC check flag
582 *
583 * If the logical eraseblock @lnum is unmapped, @buf is filled with 0xFF
584 * bytes. The @check flag only makes sense for static volumes and forces
585 * eraseblock data CRC checking.
586 *
587 * In case of success this function returns zero. In case of a static volume,
588 * if data CRC mismatches - %-EBADMSG is returned. %-EBADMSG may also be
589 * returned for any volume type if an ECC error was detected by the MTD device
590 * driver. Other negative error cored may be returned in case of other errors.
591 */
592int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
593 void *buf, int offset, int len, int check)
594{
595 int err, pnum, scrub = 0, vol_id = vol->vol_id;
596 struct ubi_vid_io_buf *vidb;
597 struct ubi_vid_hdr *vid_hdr;
598 uint32_t crc;
599
600 err = leb_read_lock(ubi, vol_id, lnum);
601 if (err)
602 return err;
603
604 pnum = vol->eba_tbl->entries[lnum].pnum;
605 if (pnum >= 0) {
606 err = check_mapping(ubi, vol, lnum, pnum: &pnum);
607 if (err < 0)
608 goto out_unlock;
609 }
610
611 if (pnum == UBI_LEB_UNMAPPED) {
612 /*
613 * The logical eraseblock is not mapped, fill the whole buffer
614 * with 0xFF bytes. The exception is static volumes for which
615 * it is an error to read unmapped logical eraseblocks.
616 */
617 dbg_eba("read %d bytes from offset %d of LEB %d:%d (unmapped)",
618 len, offset, vol_id, lnum);
619 leb_read_unlock(ubi, vol_id, lnum);
620 ubi_assert(vol->vol_type != UBI_STATIC_VOLUME);
621 memset(buf, 0xFF, len);
622 return 0;
623 }
624
625 dbg_eba("read %d bytes from offset %d of LEB %d:%d, PEB %d",
626 len, offset, vol_id, lnum, pnum);
627
628 if (vol->vol_type == UBI_DYNAMIC_VOLUME)
629 check = 0;
630
631retry:
632 if (check) {
633 vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
634 if (!vidb) {
635 err = -ENOMEM;
636 goto out_unlock;
637 }
638
639 vid_hdr = ubi_get_vid_hdr(vidb);
640
641 err = ubi_io_read_vid_hdr(ubi, pnum, vidb, verbose: 1);
642 if (err && err != UBI_IO_BITFLIPS) {
643 if (err > 0) {
644 /*
645 * The header is either absent or corrupted.
646 * The former case means there is a bug -
647 * switch to read-only mode just in case.
648 * The latter case means a real corruption - we
649 * may try to recover data. FIXME: but this is
650 * not implemented.
651 */
652 if (err == UBI_IO_BAD_HDR_EBADMSG ||
653 err == UBI_IO_BAD_HDR) {
654 ubi_warn(ubi, fmt: "corrupted VID header at PEB %d, LEB %d:%d",
655 pnum, vol_id, lnum);
656 err = -EBADMSG;
657 } else {
658 /*
659 * Ending up here in the non-Fastmap case
660 * is a clear bug as the VID header had to
661 * be present at scan time to have it referenced.
662 * With fastmap the story is more complicated.
663 * Fastmap has the mapping info without the need
664 * of a full scan. So the LEB could have been
665 * unmapped, Fastmap cannot know this and keeps
666 * the LEB referenced.
667 * This is valid and works as the layer above UBI
668 * has to do bookkeeping about used/referenced
669 * LEBs in any case.
670 */
671 if (ubi->fast_attach) {
672 err = -EBADMSG;
673 } else {
674 err = -EINVAL;
675 ubi_ro_mode(ubi);
676 }
677 }
678 }
679 goto out_free;
680 } else if (err == UBI_IO_BITFLIPS)
681 scrub = 1;
682
683 ubi_assert(lnum < be32_to_cpu(vid_hdr->used_ebs));
684 ubi_assert(len == be32_to_cpu(vid_hdr->data_size));
685
686 crc = be32_to_cpu(vid_hdr->data_crc);
687 ubi_free_vid_buf(vidb);
688 }
689
690 err = ubi_io_read_data(ubi, buf, pnum, offset, len);
691 if (err) {
692 if (err == UBI_IO_BITFLIPS)
693 scrub = 1;
694 else if (mtd_is_eccerr(err)) {
695 if (vol->vol_type == UBI_DYNAMIC_VOLUME)
696 goto out_unlock;
697 scrub = 1;
698 if (!check) {
699 ubi_msg(ubi, fmt: "force data checking");
700 check = 1;
701 goto retry;
702 }
703 } else
704 goto out_unlock;
705 }
706
707 if (check) {
708 uint32_t crc1 = crc32(UBI_CRC32_INIT, p: buf, len);
709 if (crc1 != crc) {
710 ubi_warn(ubi, fmt: "CRC error: calculated %#08x, must be %#08x",
711 crc1, crc);
712 err = -EBADMSG;
713 goto out_unlock;
714 }
715 }
716
717 if (scrub)
718 err = ubi_wl_scrub_peb(ubi, pnum);
719
720 leb_read_unlock(ubi, vol_id, lnum);
721 return err;
722
723out_free:
724 ubi_free_vid_buf(vidb);
725out_unlock:
726 leb_read_unlock(ubi, vol_id, lnum);
727 return err;
728}
729
730/**
731 * ubi_eba_read_leb_sg - read data into a scatter gather list.
732 * @ubi: UBI device description object
733 * @vol: volume description object
734 * @lnum: logical eraseblock number
735 * @sgl: UBI scatter gather list to store the read data
736 * @offset: offset from where to read
737 * @len: how many bytes to read
738 * @check: data CRC check flag
739 *
740 * This function works exactly like ubi_eba_read_leb(). But instead of
741 * storing the read data into a buffer it writes to an UBI scatter gather
742 * list.
743 */
744int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol,
745 struct ubi_sgl *sgl, int lnum, int offset, int len,
746 int check)
747{
748 int to_read;
749 int ret;
750 struct scatterlist *sg;
751
752 for (;;) {
753 ubi_assert(sgl->list_pos < UBI_MAX_SG_COUNT);
754 sg = &sgl->sg[sgl->list_pos];
755 if (len < sg->length - sgl->page_pos)
756 to_read = len;
757 else
758 to_read = sg->length - sgl->page_pos;
759
760 ret = ubi_eba_read_leb(ubi, vol, lnum,
761 buf: sg_virt(sg) + sgl->page_pos, offset,
762 len: to_read, check);
763 if (ret < 0)
764 return ret;
765
766 offset += to_read;
767 len -= to_read;
768 if (!len) {
769 sgl->page_pos += to_read;
770 if (sgl->page_pos == sg->length) {
771 sgl->list_pos++;
772 sgl->page_pos = 0;
773 }
774
775 break;
776 }
777
778 sgl->list_pos++;
779 sgl->page_pos = 0;
780 }
781
782 return ret;
783}
784
785/**
786 * try_recover_peb - try to recover from write failure.
787 * @vol: volume description object
788 * @pnum: the physical eraseblock to recover
789 * @lnum: logical eraseblock number
790 * @buf: data which was not written because of the write failure
791 * @offset: offset of the failed write
792 * @len: how many bytes should have been written
793 * @vidb: VID buffer
794 * @retry: whether the caller should retry in case of failure
795 *
796 * This function is called in case of a write failure and moves all good data
797 * from the potentially bad physical eraseblock to a good physical eraseblock.
798 * This function also writes the data which was not written due to the failure.
799 * Returns 0 in case of success, and a negative error code in case of failure.
800 * In case of failure, the %retry parameter is set to false if this is a fatal
801 * error (retrying won't help), and true otherwise.
802 */
803static int try_recover_peb(struct ubi_volume *vol, int pnum, int lnum,
804 const void *buf, int offset, int len,
805 struct ubi_vid_io_buf *vidb, bool *retry)
806{
807 struct ubi_device *ubi = vol->ubi;
808 struct ubi_vid_hdr *vid_hdr;
809 int new_pnum, err, vol_id = vol->vol_id, data_size;
810 uint32_t crc;
811
812 *retry = false;
813
814 new_pnum = ubi_wl_get_peb(ubi);
815 if (new_pnum < 0) {
816 err = new_pnum;
817 goto out_put;
818 }
819
820 ubi_msg(ubi, fmt: "recover PEB %d, move data to PEB %d",
821 pnum, new_pnum);
822
823 err = ubi_io_read_vid_hdr(ubi, pnum, vidb, verbose: 1);
824 if (err && err != UBI_IO_BITFLIPS) {
825 if (err > 0)
826 err = -EIO;
827 goto out_put;
828 }
829
830 vid_hdr = ubi_get_vid_hdr(vidb);
831 ubi_assert(vid_hdr->vol_type == UBI_VID_DYNAMIC);
832
833 mutex_lock(&ubi->buf_mutex);
834 memset(ubi->peb_buf + offset, 0xFF, len);
835
836 /* Read everything before the area where the write failure happened */
837 if (offset > 0) {
838 err = ubi_io_read_data(ubi, buf: ubi->peb_buf, pnum, offset: 0, len: offset);
839 if (err && err != UBI_IO_BITFLIPS)
840 goto out_unlock;
841 }
842
843 *retry = true;
844
845 memcpy(ubi->peb_buf + offset, buf, len);
846
847 data_size = offset + len;
848 crc = crc32(UBI_CRC32_INIT, p: ubi->peb_buf, len: data_size);
849 vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
850 vid_hdr->copy_flag = 1;
851 vid_hdr->data_size = cpu_to_be32(data_size);
852 vid_hdr->data_crc = cpu_to_be32(crc);
853 err = ubi_io_write_vid_hdr(ubi, pnum: new_pnum, vidb);
854 if (err)
855 goto out_unlock;
856
857 err = ubi_io_write_data(ubi, buf: ubi->peb_buf, pnum: new_pnum, offset: 0, len: data_size);
858
859out_unlock:
860 mutex_unlock(lock: &ubi->buf_mutex);
861
862 if (!err)
863 vol->eba_tbl->entries[lnum].pnum = new_pnum;
864
865out_put:
866 up_read(sem: &ubi->fm_eba_sem);
867
868 if (!err) {
869 ubi_wl_put_peb(ubi, vol_id, lnum, pnum, torture: 1);
870 ubi_msg(ubi, fmt: "data was successfully recovered");
871 } else if (new_pnum >= 0) {
872 /*
873 * Bad luck? This physical eraseblock is bad too? Crud. Let's
874 * try to get another one.
875 */
876 ubi_wl_put_peb(ubi, vol_id, lnum, pnum: new_pnum, torture: 1);
877 ubi_warn(ubi, fmt: "failed to write to PEB %d", new_pnum);
878 }
879
880 return err;
881}
882
883/**
884 * recover_peb - recover from write failure.
885 * @ubi: UBI device description object
886 * @pnum: the physical eraseblock to recover
887 * @vol_id: volume ID
888 * @lnum: logical eraseblock number
889 * @buf: data which was not written because of the write failure
890 * @offset: offset of the failed write
891 * @len: how many bytes should have been written
892 *
893 * This function is called in case of a write failure and moves all good data
894 * from the potentially bad physical eraseblock to a good physical eraseblock.
895 * This function also writes the data which was not written due to the failure.
896 * Returns 0 in case of success, and a negative error code in case of failure.
897 * This function tries %UBI_IO_RETRIES before giving up.
898 */
899static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
900 const void *buf, int offset, int len)
901{
902 int err, idx = vol_id2idx(ubi, vol_id), tries;
903 struct ubi_volume *vol = ubi->volumes[idx];
904 struct ubi_vid_io_buf *vidb;
905
906 vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
907 if (!vidb)
908 return -ENOMEM;
909
910 for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
911 bool retry;
912
913 err = try_recover_peb(vol, pnum, lnum, buf, offset, len, vidb,
914 retry: &retry);
915 if (!err || !retry)
916 break;
917
918 ubi_msg(ubi, fmt: "try again");
919 }
920
921 ubi_free_vid_buf(vidb);
922
923 return err;
924}
925
926/**
927 * try_write_vid_and_data - try to write VID header and data to a new PEB.
928 * @vol: volume description object
929 * @lnum: logical eraseblock number
930 * @vidb: the VID buffer to write
931 * @buf: buffer containing the data
932 * @offset: where to start writing data
933 * @len: how many bytes should be written
934 *
935 * This function tries to write VID header and data belonging to logical
936 * eraseblock @lnum of volume @vol to a new physical eraseblock. Returns zero
937 * in case of success and a negative error code in case of failure.
938 * In case of error, it is possible that something was still written to the
939 * flash media, but may be some garbage.
940 */
941static int try_write_vid_and_data(struct ubi_volume *vol, int lnum,
942 struct ubi_vid_io_buf *vidb, const void *buf,
943 int offset, int len)
944{
945 struct ubi_device *ubi = vol->ubi;
946 int pnum, opnum, err, err2, vol_id = vol->vol_id;
947
948 pnum = ubi_wl_get_peb(ubi);
949 if (pnum < 0) {
950 err = pnum;
951 goto out_put;
952 }
953
954 opnum = vol->eba_tbl->entries[lnum].pnum;
955
956 dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
957 len, offset, vol_id, lnum, pnum);
958
959 err = ubi_io_write_vid_hdr(ubi, pnum, vidb);
960 if (err) {
961 ubi_warn(ubi, fmt: "failed to write VID header to LEB %d:%d, PEB %d",
962 vol_id, lnum, pnum);
963 goto out_put;
964 }
965
966 if (len) {
967 err = ubi_io_write_data(ubi, buf, pnum, offset, len);
968 if (err) {
969 ubi_warn(ubi,
970 fmt: "failed to write %d bytes at offset %d of LEB %d:%d, PEB %d",
971 len, offset, vol_id, lnum, pnum);
972 goto out_put;
973 }
974 }
975
976 vol->eba_tbl->entries[lnum].pnum = pnum;
977
978out_put:
979 up_read(sem: &ubi->fm_eba_sem);
980
981 if (err && pnum >= 0) {
982 err2 = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, torture: 1);
983 if (err2) {
984 ubi_warn(ubi, fmt: "failed to return physical eraseblock %d, error %d",
985 pnum, err2);
986 }
987 } else if (!err && opnum >= 0) {
988 err2 = ubi_wl_put_peb(ubi, vol_id, lnum, pnum: opnum, torture: 0);
989 if (err2) {
990 ubi_warn(ubi, fmt: "failed to return physical eraseblock %d, error %d",
991 opnum, err2);
992 }
993 }
994
995 return err;
996}
997
998/**
999 * ubi_eba_write_leb - write data to dynamic volume.
1000 * @ubi: UBI device description object
1001 * @vol: volume description object
1002 * @lnum: logical eraseblock number
1003 * @buf: the data to write
1004 * @offset: offset within the logical eraseblock where to write
1005 * @len: how many bytes to write
1006 *
1007 * This function writes data to logical eraseblock @lnum of a dynamic volume
1008 * @vol. Returns zero in case of success and a negative error code in case
1009 * of failure. In case of error, it is possible that something was still
1010 * written to the flash media, but may be some garbage.
1011 * This function retries %UBI_IO_RETRIES times before giving up.
1012 */
1013int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
1014 const void *buf, int offset, int len)
1015{
1016 int err, pnum, tries, vol_id = vol->vol_id;
1017 struct ubi_vid_io_buf *vidb;
1018 struct ubi_vid_hdr *vid_hdr;
1019
1020 if (ubi->ro_mode)
1021 return -EROFS;
1022
1023 err = leb_write_lock(ubi, vol_id, lnum);
1024 if (err)
1025 return err;
1026
1027 pnum = vol->eba_tbl->entries[lnum].pnum;
1028 if (pnum >= 0) {
1029 err = check_mapping(ubi, vol, lnum, pnum: &pnum);
1030 if (err < 0)
1031 goto out;
1032 }
1033
1034 if (pnum >= 0) {
1035 dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d",
1036 len, offset, vol_id, lnum, pnum);
1037
1038 err = ubi_io_write_data(ubi, buf, pnum, offset, len);
1039 if (err) {
1040 ubi_warn(ubi, fmt: "failed to write data to PEB %d", pnum);
1041 if (err == -EIO && ubi->bad_allowed)
1042 err = recover_peb(ubi, pnum, vol_id, lnum, buf,
1043 offset, len);
1044 }
1045
1046 goto out;
1047 }
1048
1049 /*
1050 * The logical eraseblock is not mapped. We have to get a free physical
1051 * eraseblock and write the volume identifier header there first.
1052 */
1053 vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1054 if (!vidb) {
1055 leb_write_unlock(ubi, vol_id, lnum);
1056 return -ENOMEM;
1057 }
1058
1059 vid_hdr = ubi_get_vid_hdr(vidb);
1060
1061 vid_hdr->vol_type = UBI_VID_DYNAMIC;
1062 vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1063 vid_hdr->vol_id = cpu_to_be32(vol_id);
1064 vid_hdr->lnum = cpu_to_be32(lnum);
1065 vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1066 vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1067
1068 for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1069 err = try_write_vid_and_data(vol, lnum, vidb, buf, offset, len);
1070 if (err != -EIO || !ubi->bad_allowed)
1071 break;
1072
1073 /*
1074 * Fortunately, this is the first write operation to this
1075 * physical eraseblock, so just put it and request a new one.
1076 * We assume that if this physical eraseblock went bad, the
1077 * erase code will handle that.
1078 */
1079 vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1080 ubi_msg(ubi, fmt: "try another PEB");
1081 }
1082
1083 ubi_free_vid_buf(vidb);
1084
1085out:
1086 if (err)
1087 ubi_ro_mode(ubi);
1088
1089 leb_write_unlock(ubi, vol_id, lnum);
1090
1091 return err;
1092}
1093
1094/**
1095 * ubi_eba_write_leb_st - write data to static volume.
1096 * @ubi: UBI device description object
1097 * @vol: volume description object
1098 * @lnum: logical eraseblock number
1099 * @buf: data to write
1100 * @len: how many bytes to write
1101 * @used_ebs: how many logical eraseblocks will this volume contain
1102 *
1103 * This function writes data to logical eraseblock @lnum of static volume
1104 * @vol. The @used_ebs argument should contain total number of logical
1105 * eraseblock in this static volume.
1106 *
1107 * When writing to the last logical eraseblock, the @len argument doesn't have
1108 * to be aligned to the minimal I/O unit size. Instead, it has to be equivalent
1109 * to the real data size, although the @buf buffer has to contain the
1110 * alignment. In all other cases, @len has to be aligned.
1111 *
1112 * It is prohibited to write more than once to logical eraseblocks of static
1113 * volumes. This function returns zero in case of success and a negative error
1114 * code in case of failure.
1115 */
1116int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
1117 int lnum, const void *buf, int len, int used_ebs)
1118{
1119 int err, tries, data_size = len, vol_id = vol->vol_id;
1120 struct ubi_vid_io_buf *vidb;
1121 struct ubi_vid_hdr *vid_hdr;
1122 uint32_t crc;
1123
1124 if (ubi->ro_mode)
1125 return -EROFS;
1126
1127 if (lnum == used_ebs - 1)
1128 /* If this is the last LEB @len may be unaligned */
1129 len = ALIGN(data_size, ubi->min_io_size);
1130 else
1131 ubi_assert(!(len & (ubi->min_io_size - 1)));
1132
1133 vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1134 if (!vidb)
1135 return -ENOMEM;
1136
1137 vid_hdr = ubi_get_vid_hdr(vidb);
1138
1139 err = leb_write_lock(ubi, vol_id, lnum);
1140 if (err)
1141 goto out;
1142
1143 vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1144 vid_hdr->vol_id = cpu_to_be32(vol_id);
1145 vid_hdr->lnum = cpu_to_be32(lnum);
1146 vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1147 vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1148
1149 crc = crc32(UBI_CRC32_INIT, p: buf, len: data_size);
1150 vid_hdr->vol_type = UBI_VID_STATIC;
1151 vid_hdr->data_size = cpu_to_be32(data_size);
1152 vid_hdr->used_ebs = cpu_to_be32(used_ebs);
1153 vid_hdr->data_crc = cpu_to_be32(crc);
1154
1155 ubi_assert(vol->eba_tbl->entries[lnum].pnum < 0);
1156
1157 for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1158 err = try_write_vid_and_data(vol, lnum, vidb, buf, offset: 0, len);
1159 if (err != -EIO || !ubi->bad_allowed)
1160 break;
1161
1162 vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1163 ubi_msg(ubi, fmt: "try another PEB");
1164 }
1165
1166 if (err)
1167 ubi_ro_mode(ubi);
1168
1169 leb_write_unlock(ubi, vol_id, lnum);
1170
1171out:
1172 ubi_free_vid_buf(vidb);
1173
1174 return err;
1175}
1176
1177/*
1178 * ubi_eba_atomic_leb_change - change logical eraseblock atomically.
1179 * @ubi: UBI device description object
1180 * @vol: volume description object
1181 * @lnum: logical eraseblock number
1182 * @buf: data to write
1183 * @len: how many bytes to write
1184 *
1185 * This function changes the contents of a logical eraseblock atomically. @buf
1186 * has to contain new logical eraseblock data, and @len - the length of the
1187 * data, which has to be aligned. This function guarantees that in case of an
1188 * unclean reboot the old contents is preserved. Returns zero in case of
1189 * success and a negative error code in case of failure.
1190 *
1191 * UBI reserves one LEB for the "atomic LEB change" operation, so only one
1192 * LEB change may be done at a time. This is ensured by @ubi->alc_mutex.
1193 */
1194int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
1195 int lnum, const void *buf, int len)
1196{
1197 int err, tries, vol_id = vol->vol_id;
1198 struct ubi_vid_io_buf *vidb;
1199 struct ubi_vid_hdr *vid_hdr;
1200 uint32_t crc;
1201
1202 if (ubi->ro_mode)
1203 return -EROFS;
1204
1205 if (len == 0) {
1206 /*
1207 * Special case when data length is zero. In this case the LEB
1208 * has to be unmapped and mapped somewhere else.
1209 */
1210 err = ubi_eba_unmap_leb(ubi, vol, lnum);
1211 if (err)
1212 return err;
1213 return ubi_eba_write_leb(ubi, vol, lnum, NULL, offset: 0, len: 0);
1214 }
1215
1216 vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1217 if (!vidb)
1218 return -ENOMEM;
1219
1220 vid_hdr = ubi_get_vid_hdr(vidb);
1221
1222 mutex_lock(&ubi->alc_mutex);
1223 err = leb_write_lock(ubi, vol_id, lnum);
1224 if (err)
1225 goto out_mutex;
1226
1227 vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1228 vid_hdr->vol_id = cpu_to_be32(vol_id);
1229 vid_hdr->lnum = cpu_to_be32(lnum);
1230 vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1231 vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1232
1233 crc = crc32(UBI_CRC32_INIT, p: buf, len);
1234 vid_hdr->vol_type = UBI_VID_DYNAMIC;
1235 vid_hdr->data_size = cpu_to_be32(len);
1236 vid_hdr->copy_flag = 1;
1237 vid_hdr->data_crc = cpu_to_be32(crc);
1238
1239 dbg_eba("change LEB %d:%d", vol_id, lnum);
1240
1241 for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1242 err = try_write_vid_and_data(vol, lnum, vidb, buf, offset: 0, len);
1243 if (err != -EIO || !ubi->bad_allowed)
1244 break;
1245
1246 vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1247 ubi_msg(ubi, fmt: "try another PEB");
1248 }
1249
1250 /*
1251 * This flash device does not admit of bad eraseblocks or
1252 * something nasty and unexpected happened. Switch to read-only
1253 * mode just in case.
1254 */
1255 if (err)
1256 ubi_ro_mode(ubi);
1257
1258 leb_write_unlock(ubi, vol_id, lnum);
1259
1260out_mutex:
1261 mutex_unlock(lock: &ubi->alc_mutex);
1262 ubi_free_vid_buf(vidb);
1263 return err;
1264}
1265
1266/**
1267 * is_error_sane - check whether a read error is sane.
1268 * @err: code of the error happened during reading
1269 *
1270 * This is a helper function for 'ubi_eba_copy_leb()' which is called when we
1271 * cannot read data from the target PEB (an error @err happened). If the error
1272 * code is sane, then we treat this error as non-fatal. Otherwise the error is
1273 * fatal and UBI will be switched to R/O mode later.
1274 *
1275 * The idea is that we try not to switch to R/O mode if the read error is
1276 * something which suggests there was a real read problem. E.g., %-EIO. Or a
1277 * memory allocation failed (-%ENOMEM). Otherwise, it is safer to switch to R/O
1278 * mode, simply because we do not know what happened at the MTD level, and we
1279 * cannot handle this. E.g., the underlying driver may have become crazy, and
1280 * it is safer to switch to R/O mode to preserve the data.
1281 *
1282 * And bear in mind, this is about reading from the target PEB, i.e. the PEB
1283 * which we have just written.
1284 */
1285static int is_error_sane(int err)
1286{
1287 if (err == -EIO || err == -ENOMEM || err == UBI_IO_BAD_HDR ||
1288 err == UBI_IO_BAD_HDR_EBADMSG || err == -ETIMEDOUT)
1289 return 0;
1290 return 1;
1291}
1292
1293/**
1294 * ubi_eba_copy_leb - copy logical eraseblock.
1295 * @ubi: UBI device description object
1296 * @from: physical eraseblock number from where to copy
1297 * @to: physical eraseblock number where to copy
1298 * @vidb: data structure from where the VID header is derived
1299 *
1300 * This function copies logical eraseblock from physical eraseblock @from to
1301 * physical eraseblock @to. The @vid_hdr buffer may be changed by this
1302 * function. Returns:
1303 * o %0 in case of success;
1304 * o %MOVE_CANCEL_RACE, %MOVE_TARGET_WR_ERR, %MOVE_TARGET_BITFLIPS, etc;
1305 * o a negative error code in case of failure.
1306 */
1307int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
1308 struct ubi_vid_io_buf *vidb)
1309{
1310 int err, vol_id, lnum, data_size, aldata_size, idx;
1311 struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
1312 struct ubi_volume *vol;
1313 uint32_t crc;
1314
1315 ubi_assert(rwsem_is_locked(&ubi->fm_eba_sem));
1316
1317 vol_id = be32_to_cpu(vid_hdr->vol_id);
1318 lnum = be32_to_cpu(vid_hdr->lnum);
1319
1320 dbg_wl("copy LEB %d:%d, PEB %d to PEB %d", vol_id, lnum, from, to);
1321
1322 if (vid_hdr->vol_type == UBI_VID_STATIC) {
1323 data_size = be32_to_cpu(vid_hdr->data_size);
1324 aldata_size = ALIGN(data_size, ubi->min_io_size);
1325 } else
1326 data_size = aldata_size =
1327 ubi->leb_size - be32_to_cpu(vid_hdr->data_pad);
1328
1329 idx = vol_id2idx(ubi, vol_id);
1330 spin_lock(lock: &ubi->volumes_lock);
1331 /*
1332 * Note, we may race with volume deletion, which means that the volume
1333 * this logical eraseblock belongs to might be being deleted. Since the
1334 * volume deletion un-maps all the volume's logical eraseblocks, it will
1335 * be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish.
1336 */
1337 vol = ubi->volumes[idx];
1338 spin_unlock(lock: &ubi->volumes_lock);
1339 if (!vol) {
1340 /* No need to do further work, cancel */
1341 dbg_wl("volume %d is being removed, cancel", vol_id);
1342 return MOVE_CANCEL_RACE;
1343 }
1344
1345 /*
1346 * We do not want anybody to write to this logical eraseblock while we
1347 * are moving it, so lock it.
1348 *
1349 * Note, we are using non-waiting locking here, because we cannot sleep
1350 * on the LEB, since it may cause deadlocks. Indeed, imagine a task is
1351 * unmapping the LEB which is mapped to the PEB we are going to move
1352 * (@from). This task locks the LEB and goes sleep in the
1353 * 'ubi_wl_put_peb()' function on the @ubi->move_mutex. In turn, we are
1354 * holding @ubi->move_mutex and go sleep on the LEB lock. So, if the
1355 * LEB is already locked, we just do not move it and return
1356 * %MOVE_RETRY. Note, we do not return %MOVE_CANCEL_RACE here because
1357 * we do not know the reasons of the contention - it may be just a
1358 * normal I/O on this LEB, so we want to re-try.
1359 */
1360 err = leb_write_trylock(ubi, vol_id, lnum);
1361 if (err) {
1362 dbg_wl("contention on LEB %d:%d, cancel", vol_id, lnum);
1363 return MOVE_RETRY;
1364 }
1365
1366 /*
1367 * The LEB might have been put meanwhile, and the task which put it is
1368 * probably waiting on @ubi->move_mutex. No need to continue the work,
1369 * cancel it.
1370 */
1371 if (vol->eba_tbl->entries[lnum].pnum != from) {
1372 dbg_wl("LEB %d:%d is no longer mapped to PEB %d, mapped to PEB %d, cancel",
1373 vol_id, lnum, from, vol->eba_tbl->entries[lnum].pnum);
1374 err = MOVE_CANCEL_RACE;
1375 goto out_unlock_leb;
1376 }
1377
1378 /*
1379 * OK, now the LEB is locked and we can safely start moving it. Since
1380 * this function utilizes the @ubi->peb_buf buffer which is shared
1381 * with some other functions - we lock the buffer by taking the
1382 * @ubi->buf_mutex.
1383 */
1384 mutex_lock(&ubi->buf_mutex);
1385 dbg_wl("read %d bytes of data", aldata_size);
1386 err = ubi_io_read_data(ubi, buf: ubi->peb_buf, pnum: from, offset: 0, len: aldata_size);
1387 if (err && err != UBI_IO_BITFLIPS) {
1388 ubi_warn(ubi, fmt: "error %d while reading data from PEB %d",
1389 err, from);
1390 err = MOVE_SOURCE_RD_ERR;
1391 goto out_unlock_buf;
1392 }
1393
1394 /*
1395 * Now we have got to calculate how much data we have to copy. In
1396 * case of a static volume it is fairly easy - the VID header contains
1397 * the data size. In case of a dynamic volume it is more difficult - we
1398 * have to read the contents, cut 0xFF bytes from the end and copy only
1399 * the first part. We must do this to avoid writing 0xFF bytes as it
1400 * may have some side-effects. And not only this. It is important not
1401 * to include those 0xFFs to CRC because later the they may be filled
1402 * by data.
1403 */
1404 if (vid_hdr->vol_type == UBI_VID_DYNAMIC)
1405 aldata_size = data_size =
1406 ubi_calc_data_len(ubi, buf: ubi->peb_buf, length: data_size);
1407
1408 cond_resched();
1409 crc = crc32(UBI_CRC32_INIT, p: ubi->peb_buf, len: data_size);
1410 cond_resched();
1411
1412 /*
1413 * It may turn out to be that the whole @from physical eraseblock
1414 * contains only 0xFF bytes. Then we have to only write the VID header
1415 * and do not write any data. This also means we should not set
1416 * @vid_hdr->copy_flag, @vid_hdr->data_size, and @vid_hdr->data_crc.
1417 */
1418 if (data_size > 0) {
1419 vid_hdr->copy_flag = 1;
1420 vid_hdr->data_size = cpu_to_be32(data_size);
1421 vid_hdr->data_crc = cpu_to_be32(crc);
1422 }
1423 vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1424
1425 err = ubi_io_write_vid_hdr(ubi, pnum: to, vidb);
1426 if (err) {
1427 if (err == -EIO)
1428 err = MOVE_TARGET_WR_ERR;
1429 goto out_unlock_buf;
1430 }
1431
1432 cond_resched();
1433
1434 /* Read the VID header back and check if it was written correctly */
1435 err = ubi_io_read_vid_hdr(ubi, pnum: to, vidb, verbose: 1);
1436 if (err) {
1437 if (err != UBI_IO_BITFLIPS) {
1438 ubi_warn(ubi, fmt: "error %d while reading VID header back from PEB %d",
1439 err, to);
1440 if (is_error_sane(err))
1441 err = MOVE_TARGET_RD_ERR;
1442 } else
1443 err = MOVE_TARGET_BITFLIPS;
1444 goto out_unlock_buf;
1445 }
1446
1447 if (data_size > 0) {
1448 err = ubi_io_write_data(ubi, buf: ubi->peb_buf, pnum: to, offset: 0, len: aldata_size);
1449 if (err) {
1450 if (err == -EIO)
1451 err = MOVE_TARGET_WR_ERR;
1452 goto out_unlock_buf;
1453 }
1454
1455 cond_resched();
1456 }
1457
1458 ubi_assert(vol->eba_tbl->entries[lnum].pnum == from);
1459
1460 /**
1461 * The volumes_lock lock is needed here to prevent the expired old eba_tbl
1462 * being updated when the eba_tbl is copied in the ubi_resize_volume() process.
1463 */
1464 spin_lock(lock: &ubi->volumes_lock);
1465 vol->eba_tbl->entries[lnum].pnum = to;
1466 spin_unlock(lock: &ubi->volumes_lock);
1467
1468out_unlock_buf:
1469 mutex_unlock(lock: &ubi->buf_mutex);
1470out_unlock_leb:
1471 leb_write_unlock(ubi, vol_id, lnum);
1472 return err;
1473}
1474
1475/**
1476 * print_rsvd_warning - warn about not having enough reserved PEBs.
1477 * @ubi: UBI device description object
1478 * @ai: UBI attach info object
1479 *
1480 * This is a helper function for 'ubi_eba_init()' which is called when UBI
1481 * cannot reserve enough PEBs for bad block handling. This function makes a
1482 * decision whether we have to print a warning or not. The algorithm is as
1483 * follows:
1484 * o if this is a new UBI image, then just print the warning
1485 * o if this is an UBI image which has already been used for some time, print
1486 * a warning only if we can reserve less than 10% of the expected amount of
1487 * the reserved PEB.
1488 *
1489 * The idea is that when UBI is used, PEBs become bad, and the reserved pool
1490 * of PEBs becomes smaller, which is normal and we do not want to scare users
1491 * with a warning every time they attach the MTD device. This was an issue
1492 * reported by real users.
1493 */
1494static void print_rsvd_warning(struct ubi_device *ubi,
1495 struct ubi_attach_info *ai)
1496{
1497 /*
1498 * The 1 << 18 (256KiB) number is picked randomly, just a reasonably
1499 * large number to distinguish between newly flashed and used images.
1500 */
1501 if (ai->max_sqnum > (1 << 18)) {
1502 int min = ubi->beb_rsvd_level / 10;
1503
1504 if (!min)
1505 min = 1;
1506 if (ubi->beb_rsvd_pebs > min)
1507 return;
1508 }
1509
1510 ubi_warn(ubi, fmt: "cannot reserve enough PEBs for bad PEB handling, reserved %d, need %d",
1511 ubi->beb_rsvd_pebs, ubi->beb_rsvd_level);
1512 if (ubi->corr_peb_count)
1513 ubi_warn(ubi, fmt: "%d PEBs are corrupted and not used",
1514 ubi->corr_peb_count);
1515}
1516
1517/**
1518 * self_check_eba - run a self check on the EBA table constructed by fastmap.
1519 * @ubi: UBI device description object
1520 * @ai_fastmap: UBI attach info object created by fastmap
1521 * @ai_scan: UBI attach info object created by scanning
1522 *
1523 * Returns < 0 in case of an internal error, 0 otherwise.
1524 * If a bad EBA table entry was found it will be printed out and
1525 * ubi_assert() triggers.
1526 */
1527int self_check_eba(struct ubi_device *ubi, struct ubi_attach_info *ai_fastmap,
1528 struct ubi_attach_info *ai_scan)
1529{
1530 int i, j, num_volumes, ret = 0;
1531 int **scan_eba, **fm_eba;
1532 struct ubi_ainf_volume *av;
1533 struct ubi_volume *vol;
1534 struct ubi_ainf_peb *aeb;
1535 struct rb_node *rb;
1536
1537 num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
1538
1539 scan_eba = kmalloc_array(num_volumes, sizeof(*scan_eba), GFP_KERNEL);
1540 if (!scan_eba)
1541 return -ENOMEM;
1542
1543 fm_eba = kmalloc_array(num_volumes, sizeof(*fm_eba), GFP_KERNEL);
1544 if (!fm_eba) {
1545 kfree(objp: scan_eba);
1546 return -ENOMEM;
1547 }
1548
1549 for (i = 0; i < num_volumes; i++) {
1550 vol = ubi->volumes[i];
1551 if (!vol)
1552 continue;
1553
1554 scan_eba[i] = kmalloc_array(vol->reserved_pebs,
1555 sizeof(**scan_eba),
1556 GFP_KERNEL);
1557 if (!scan_eba[i]) {
1558 ret = -ENOMEM;
1559 goto out_free;
1560 }
1561
1562 fm_eba[i] = kmalloc_array(vol->reserved_pebs,
1563 sizeof(**fm_eba),
1564 GFP_KERNEL);
1565 if (!fm_eba[i]) {
1566 ret = -ENOMEM;
1567 kfree(objp: scan_eba[i]);
1568 goto out_free;
1569 }
1570
1571 for (j = 0; j < vol->reserved_pebs; j++)
1572 scan_eba[i][j] = fm_eba[i][j] = UBI_LEB_UNMAPPED;
1573
1574 av = ubi_find_av(ai: ai_scan, vol_id: idx2vol_id(ubi, idx: i));
1575 if (!av)
1576 continue;
1577
1578 ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb)
1579 scan_eba[i][aeb->lnum] = aeb->pnum;
1580
1581 av = ubi_find_av(ai: ai_fastmap, vol_id: idx2vol_id(ubi, idx: i));
1582 if (!av)
1583 continue;
1584
1585 ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb)
1586 fm_eba[i][aeb->lnum] = aeb->pnum;
1587
1588 for (j = 0; j < vol->reserved_pebs; j++) {
1589 if (scan_eba[i][j] != fm_eba[i][j]) {
1590 if (scan_eba[i][j] == UBI_LEB_UNMAPPED ||
1591 fm_eba[i][j] == UBI_LEB_UNMAPPED)
1592 continue;
1593
1594 ubi_err(ubi, fmt: "LEB:%i:%i is PEB:%i instead of %i!",
1595 vol->vol_id, j, fm_eba[i][j],
1596 scan_eba[i][j]);
1597 ubi_assert(0);
1598 }
1599 }
1600 }
1601
1602out_free:
1603 while (--i >= 0) {
1604 if (!ubi->volumes[i])
1605 continue;
1606
1607 kfree(objp: scan_eba[i]);
1608 kfree(objp: fm_eba[i]);
1609 }
1610
1611 kfree(objp: scan_eba);
1612 kfree(objp: fm_eba);
1613 return ret;
1614}
1615
1616/**
1617 * ubi_eba_init - initialize the EBA sub-system using attaching information.
1618 * @ubi: UBI device description object
1619 * @ai: attaching information
1620 *
1621 * This function returns zero in case of success and a negative error code in
1622 * case of failure.
1623 */
1624int ubi_eba_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
1625{
1626 int i, err, num_volumes;
1627 struct ubi_ainf_volume *av;
1628 struct ubi_volume *vol;
1629 struct ubi_ainf_peb *aeb;
1630 struct rb_node *rb;
1631
1632 dbg_eba("initialize EBA sub-system");
1633
1634 spin_lock_init(&ubi->ltree_lock);
1635 mutex_init(&ubi->alc_mutex);
1636 ubi->ltree = RB_ROOT;
1637
1638 ubi->global_sqnum = ai->max_sqnum + 1;
1639 num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
1640
1641 for (i = 0; i < num_volumes; i++) {
1642 struct ubi_eba_table *tbl;
1643
1644 vol = ubi->volumes[i];
1645 if (!vol)
1646 continue;
1647
1648 cond_resched();
1649
1650 tbl = ubi_eba_create_table(vol, nentries: vol->reserved_pebs);
1651 if (IS_ERR(ptr: tbl)) {
1652 err = PTR_ERR(ptr: tbl);
1653 goto out_free;
1654 }
1655
1656 ubi_eba_replace_table(vol, tbl);
1657
1658 av = ubi_find_av(ai, vol_id: idx2vol_id(ubi, idx: i));
1659 if (!av)
1660 continue;
1661
1662 ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
1663 if (aeb->lnum >= vol->reserved_pebs) {
1664 /*
1665 * This may happen in case of an unclean reboot
1666 * during re-size.
1667 */
1668 ubi_move_aeb_to_list(av, aeb, list: &ai->erase);
1669 } else {
1670 struct ubi_eba_entry *entry;
1671
1672 entry = &vol->eba_tbl->entries[aeb->lnum];
1673 entry->pnum = aeb->pnum;
1674 }
1675 }
1676 }
1677
1678 if (ubi->avail_pebs < EBA_RESERVED_PEBS) {
1679 ubi_err(ubi, fmt: "no enough physical eraseblocks (%d, need %d)",
1680 ubi->avail_pebs, EBA_RESERVED_PEBS);
1681 if (ubi->corr_peb_count)
1682 ubi_err(ubi, fmt: "%d PEBs are corrupted and not used",
1683 ubi->corr_peb_count);
1684 err = -ENOSPC;
1685 goto out_free;
1686 }
1687 ubi->avail_pebs -= EBA_RESERVED_PEBS;
1688 ubi->rsvd_pebs += EBA_RESERVED_PEBS;
1689
1690 if (ubi->bad_allowed) {
1691 ubi_calculate_reserved(ubi);
1692
1693 if (ubi->avail_pebs < ubi->beb_rsvd_level) {
1694 /* No enough free physical eraseblocks */
1695 ubi->beb_rsvd_pebs = ubi->avail_pebs;
1696 print_rsvd_warning(ubi, ai);
1697 } else
1698 ubi->beb_rsvd_pebs = ubi->beb_rsvd_level;
1699
1700 ubi->avail_pebs -= ubi->beb_rsvd_pebs;
1701 ubi->rsvd_pebs += ubi->beb_rsvd_pebs;
1702 }
1703
1704 dbg_eba("EBA sub-system is initialized");
1705 return 0;
1706
1707out_free:
1708 for (i = 0; i < num_volumes; i++) {
1709 if (!ubi->volumes[i])
1710 continue;
1711 ubi_eba_replace_table(vol: ubi->volumes[i], NULL);
1712 }
1713 return err;
1714}
1715

source code of linux/drivers/mtd/ubi/eba.c