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