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