UBI: add few more comments
[linux-2.6/mini2440.git] / drivers / mtd / ubi / scan.c
blobb24af2104a2a865e9060c0db94c7f08607719d3a
1 /*
2 * Copyright (c) International Business Machines Corp., 2006
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 * Author: Artem Bityutskiy (Битюцкий Артём)
22 * UBI scanning unit.
24 * This unit is responsible for scanning the flash media, checking UBI
25 * headers and providing complete information about the UBI flash image.
27 * The scanning information is represented by a &struct ubi_scan_info' object.
28 * Information about found volumes is represented by &struct ubi_scan_volume
29 * objects which are kept in volume RB-tree with root at the @volumes field.
30 * The RB-tree is indexed by the volume ID.
32 * Found logical eraseblocks are represented by &struct ubi_scan_leb objects.
33 * These objects are kept in per-volume RB-trees with the root at the
34 * corresponding &struct ubi_scan_volume object. To put it differently, we keep
35 * an RB-tree of per-volume objects and each of these objects is the root of
36 * RB-tree of per-eraseblock objects.
38 * Corrupted physical eraseblocks are put to the @corr list, free physical
39 * eraseblocks are put to the @free list and the physical eraseblock to be
40 * erased are put to the @erase list.
43 #include <linux/err.h>
44 #include <linux/crc32.h>
45 #include "ubi.h"
47 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
48 static int paranoid_check_si(const struct ubi_device *ubi,
49 struct ubi_scan_info *si);
50 #else
51 #define paranoid_check_si(ubi, si) 0
52 #endif
54 /* Temporary variables used during scanning */
55 static struct ubi_ec_hdr *ech;
56 static struct ubi_vid_hdr *vidh;
58 /**
59 * add_to_list - add physical eraseblock to a list.
60 * @si: scanning information
61 * @pnum: physical eraseblock number to add
62 * @ec: erase counter of the physical eraseblock
63 * @list: the list to add to
65 * This function adds physical eraseblock @pnum to free, erase, corrupted or
66 * alien lists. Returns zero in case of success and a negative error code in
67 * case of failure.
69 static int add_to_list(struct ubi_scan_info *si, int pnum, int ec,
70 struct list_head *list)
72 struct ubi_scan_leb *seb;
74 if (list == &si->free)
75 dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
76 else if (list == &si->erase)
77 dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
78 else if (list == &si->corr)
79 dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
80 else if (list == &si->alien)
81 dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
82 else
83 BUG();
85 seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
86 if (!seb)
87 return -ENOMEM;
89 seb->pnum = pnum;
90 seb->ec = ec;
91 list_add_tail(&seb->u.list, list);
92 return 0;
95 /**
96 * commit_to_mean_value - commit intermediate results to the final mean erase
97 * counter value.
98 * @si: scanning information
100 * This is a helper function which calculates partial mean erase counter mean
101 * value and adds it to the resulting mean value. As we can work only in
102 * integer arithmetic and we want to calculate the mean value of erase counter
103 * accurately, we first sum erase counter values in @si->ec_sum variable and
104 * count these components in @si->ec_count. If this temporary @si->ec_sum is
105 * going to overflow, we calculate the partial mean value
106 * (@si->ec_sum/@si->ec_count) and add it to @si->mean_ec.
108 static void commit_to_mean_value(struct ubi_scan_info *si)
110 si->ec_sum /= si->ec_count;
111 if (si->ec_sum % si->ec_count >= si->ec_count / 2)
112 si->mean_ec += 1;
113 si->mean_ec += si->ec_sum;
117 * validate_vid_hdr - check that volume identifier header is correct and
118 * consistent.
119 * @vid_hdr: the volume identifier header to check
120 * @sv: information about the volume this logical eraseblock belongs to
121 * @pnum: physical eraseblock number the VID header came from
123 * This function checks that data stored in @vid_hdr is consistent. Returns
124 * non-zero if an inconsistency was found and zero if not.
126 * Note, UBI does sanity check of everything it reads from the flash media.
127 * Most of the checks are done in the I/O unit. Here we check that the
128 * information in the VID header is consistent to the information in other VID
129 * headers of the same volume.
131 static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr,
132 const struct ubi_scan_volume *sv, int pnum)
134 int vol_type = vid_hdr->vol_type;
135 int vol_id = ubi32_to_cpu(vid_hdr->vol_id);
136 int used_ebs = ubi32_to_cpu(vid_hdr->used_ebs);
137 int data_pad = ubi32_to_cpu(vid_hdr->data_pad);
139 if (sv->leb_count != 0) {
140 int sv_vol_type;
143 * This is not the first logical eraseblock belonging to this
144 * volume. Ensure that the data in its VID header is consistent
145 * to the data in previous logical eraseblock headers.
148 if (vol_id != sv->vol_id) {
149 dbg_err("inconsistent vol_id");
150 goto bad;
153 if (sv->vol_type == UBI_STATIC_VOLUME)
154 sv_vol_type = UBI_VID_STATIC;
155 else
156 sv_vol_type = UBI_VID_DYNAMIC;
158 if (vol_type != sv_vol_type) {
159 dbg_err("inconsistent vol_type");
160 goto bad;
163 if (used_ebs != sv->used_ebs) {
164 dbg_err("inconsistent used_ebs");
165 goto bad;
168 if (data_pad != sv->data_pad) {
169 dbg_err("inconsistent data_pad");
170 goto bad;
174 return 0;
176 bad:
177 ubi_err("inconsistent VID header at PEB %d", pnum);
178 ubi_dbg_dump_vid_hdr(vid_hdr);
179 ubi_dbg_dump_sv(sv);
180 return -EINVAL;
184 * add_volume - add volume to the scanning information.
185 * @si: scanning information
186 * @vol_id: ID of the volume to add
187 * @pnum: physical eraseblock number
188 * @vid_hdr: volume identifier header
190 * If the volume corresponding to the @vid_hdr logical eraseblock is already
191 * present in the scanning information, this function does nothing. Otherwise
192 * it adds corresponding volume to the scanning information. Returns a pointer
193 * to the scanning volume object in case of success and a negative error code
194 * in case of failure.
196 static struct ubi_scan_volume *add_volume(struct ubi_scan_info *si, int vol_id,
197 int pnum,
198 const struct ubi_vid_hdr *vid_hdr)
200 struct ubi_scan_volume *sv;
201 struct rb_node **p = &si->volumes.rb_node, *parent = NULL;
203 ubi_assert(vol_id == ubi32_to_cpu(vid_hdr->vol_id));
205 /* Walk the volume RB-tree to look if this volume is already present */
206 while (*p) {
207 parent = *p;
208 sv = rb_entry(parent, struct ubi_scan_volume, rb);
210 if (vol_id == sv->vol_id)
211 return sv;
213 if (vol_id > sv->vol_id)
214 p = &(*p)->rb_left;
215 else
216 p = &(*p)->rb_right;
219 /* The volume is absent - add it */
220 sv = kmalloc(sizeof(struct ubi_scan_volume), GFP_KERNEL);
221 if (!sv)
222 return ERR_PTR(-ENOMEM);
224 sv->highest_lnum = sv->leb_count = 0;
225 si->max_sqnum = 0;
226 sv->vol_id = vol_id;
227 sv->root = RB_ROOT;
228 sv->used_ebs = ubi32_to_cpu(vid_hdr->used_ebs);
229 sv->data_pad = ubi32_to_cpu(vid_hdr->data_pad);
230 sv->compat = vid_hdr->compat;
231 sv->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
232 : UBI_STATIC_VOLUME;
233 if (vol_id > si->highest_vol_id)
234 si->highest_vol_id = vol_id;
236 rb_link_node(&sv->rb, parent, p);
237 rb_insert_color(&sv->rb, &si->volumes);
238 si->vols_found += 1;
239 dbg_bld("added volume %d", vol_id);
240 return sv;
244 * compare_lebs - find out which logical eraseblock is newer.
245 * @ubi: UBI device description object
246 * @seb: first logical eraseblock to compare
247 * @pnum: physical eraseblock number of the second logical eraseblock to
248 * compare
249 * @vid_hdr: volume identifier header of the second logical eraseblock
251 * This function compares 2 copies of a LEB and informs which one is newer. In
252 * case of success this function returns a positive value, in case of failure, a
253 * negative error code is returned. The success return codes use the following
254 * bits:
255 * o bit 0 is cleared: the first PEB (described by @seb) is newer then the
256 * second PEB (described by @pnum and @vid_hdr);
257 * o bit 0 is set: the second PEB is newer;
258 * o bit 1 is cleared: no bit-flips were detected in the newer LEB;
259 * o bit 1 is set: bit-flips were detected in the newer LEB;
260 * o bit 2 is cleared: the older LEB is not corrupted;
261 * o bit 2 is set: the older LEB is corrupted.
263 static int compare_lebs(const struct ubi_device *ubi,
264 const struct ubi_scan_leb *seb, int pnum,
265 const struct ubi_vid_hdr *vid_hdr)
267 void *buf;
268 int len, err, second_is_newer, bitflips = 0, corrupted = 0;
269 uint32_t data_crc, crc;
270 struct ubi_vid_hdr *vidh = NULL;
271 unsigned long long sqnum2 = ubi64_to_cpu(vid_hdr->sqnum);
273 if (seb->sqnum == 0 && sqnum2 == 0) {
274 long long abs, v1 = seb->leb_ver, v2 = ubi32_to_cpu(vid_hdr->leb_ver);
277 * UBI constantly increases the logical eraseblock version
278 * number and it can overflow. Thus, we have to bear in mind
279 * that versions that are close to %0xFFFFFFFF are less then
280 * versions that are close to %0.
282 * The UBI WL unit guarantees that the number of pending tasks
283 * is not greater then %0x7FFFFFFF. So, if the difference
284 * between any two versions is greater or equivalent to
285 * %0x7FFFFFFF, there was an overflow and the logical
286 * eraseblock with lower version is actually newer then the one
287 * with higher version.
289 * FIXME: but this is anyway obsolete and will be removed at
290 * some point.
293 dbg_bld("using old crappy leb_ver stuff");
295 abs = v1 - v2;
296 if (abs < 0)
297 abs = -abs;
299 if (abs < 0x7FFFFFFF)
300 /* Non-overflow situation */
301 second_is_newer = (v2 > v1);
302 else
303 second_is_newer = (v2 < v1);
304 } else
305 /* Obviously the LEB with lower sequence counter is older */
306 second_is_newer = sqnum2 > seb->sqnum;
309 * Now we know which copy is newer. If the copy flag of the PEB with
310 * newer version is not set, then we just return, otherwise we have to
311 * check data CRC. For the second PEB we already have the VID header,
312 * for the first one - we'll need to re-read it from flash.
314 * FIXME: this may be optimized so that we wouldn't read twice.
317 if (second_is_newer) {
318 if (!vid_hdr->copy_flag) {
319 /* It is not a copy, so it is newer */
320 dbg_bld("second PEB %d is newer, copy_flag is unset",
321 pnum);
322 return 1;
324 } else {
325 pnum = seb->pnum;
327 vidh = ubi_zalloc_vid_hdr(ubi);
328 if (!vidh)
329 return -ENOMEM;
331 err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
332 if (err) {
333 if (err == UBI_IO_BITFLIPS)
334 bitflips = 1;
335 else {
336 dbg_err("VID of PEB %d header is bad, but it "
337 "was OK earlier", pnum);
338 if (err > 0)
339 err = -EIO;
341 goto out_free_vidh;
345 if (!vidh->copy_flag) {
346 /* It is not a copy, so it is newer */
347 dbg_bld("first PEB %d is newer, copy_flag is unset",
348 pnum);
349 err = bitflips << 1;
350 goto out_free_vidh;
353 vid_hdr = vidh;
356 /* Read the data of the copy and check the CRC */
358 len = ubi32_to_cpu(vid_hdr->data_size);
359 buf = kmalloc(len, GFP_KERNEL);
360 if (!buf) {
361 err = -ENOMEM;
362 goto out_free_vidh;
365 err = ubi_io_read_data(ubi, buf, pnum, 0, len);
366 if (err && err != UBI_IO_BITFLIPS)
367 goto out_free_buf;
369 data_crc = ubi32_to_cpu(vid_hdr->data_crc);
370 crc = crc32(UBI_CRC32_INIT, buf, len);
371 if (crc != data_crc) {
372 dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
373 pnum, crc, data_crc);
374 corrupted = 1;
375 bitflips = 0;
376 second_is_newer = !second_is_newer;
377 } else {
378 dbg_bld("PEB %d CRC is OK", pnum);
379 bitflips = !!err;
382 kfree(buf);
383 ubi_free_vid_hdr(ubi, vidh);
385 if (second_is_newer)
386 dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
387 else
388 dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
390 return second_is_newer | (bitflips << 1) | (corrupted << 2);
392 out_free_buf:
393 kfree(buf);
394 out_free_vidh:
395 ubi_free_vid_hdr(ubi, vidh);
396 ubi_assert(err < 0);
397 return err;
401 * ubi_scan_add_used - add information about a physical eraseblock to the
402 * scanning information.
403 * @ubi: UBI device description object
404 * @si: scanning information
405 * @pnum: the physical eraseblock number
406 * @ec: erase counter
407 * @vid_hdr: the volume identifier header
408 * @bitflips: if bit-flips were detected when this physical eraseblock was read
410 * This function adds information about a used physical eraseblock to the
411 * 'used' tree of the corresponding volume. The function is rather complex
412 * because it has to handle cases when this is not the first physical
413 * eraseblock belonging to the same logical eraseblock, and the newer one has
414 * to be picked, while the older one has to be dropped. This function returns
415 * zero in case of success and a negative error code in case of failure.
417 int ubi_scan_add_used(const struct ubi_device *ubi, struct ubi_scan_info *si,
418 int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
419 int bitflips)
421 int err, vol_id, lnum;
422 uint32_t leb_ver;
423 unsigned long long sqnum;
424 struct ubi_scan_volume *sv;
425 struct ubi_scan_leb *seb;
426 struct rb_node **p, *parent = NULL;
428 vol_id = ubi32_to_cpu(vid_hdr->vol_id);
429 lnum = ubi32_to_cpu(vid_hdr->lnum);
430 sqnum = ubi64_to_cpu(vid_hdr->sqnum);
431 leb_ver = ubi32_to_cpu(vid_hdr->leb_ver);
433 dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, ver %u, bitflips %d",
434 pnum, vol_id, lnum, ec, sqnum, leb_ver, bitflips);
436 sv = add_volume(si, vol_id, pnum, vid_hdr);
437 if (IS_ERR(sv) < 0)
438 return PTR_ERR(sv);
441 * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
442 * if this is the first instance of this logical eraseblock or not.
444 p = &sv->root.rb_node;
445 while (*p) {
446 int cmp_res;
448 parent = *p;
449 seb = rb_entry(parent, struct ubi_scan_leb, u.rb);
450 if (lnum != seb->lnum) {
451 if (lnum < seb->lnum)
452 p = &(*p)->rb_left;
453 else
454 p = &(*p)->rb_right;
455 continue;
459 * There is already a physical eraseblock describing the same
460 * logical eraseblock present.
463 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, "
464 "LEB ver %u, EC %d", seb->pnum, seb->sqnum,
465 seb->leb_ver, seb->ec);
468 * Make sure that the logical eraseblocks have different
469 * versions. Otherwise the image is bad.
471 if (seb->leb_ver == leb_ver && leb_ver != 0) {
472 ubi_err("two LEBs with same version %u", leb_ver);
473 ubi_dbg_dump_seb(seb, 0);
474 ubi_dbg_dump_vid_hdr(vid_hdr);
475 return -EINVAL;
479 * Make sure that the logical eraseblocks have different
480 * sequence numbers. Otherwise the image is bad.
482 * FIXME: remove 'sqnum != 0' check when leb_ver is removed.
484 if (seb->sqnum == sqnum && sqnum != 0) {
485 ubi_err("two LEBs with same sequence number %llu",
486 sqnum);
487 ubi_dbg_dump_seb(seb, 0);
488 ubi_dbg_dump_vid_hdr(vid_hdr);
489 return -EINVAL;
493 * Now we have to drop the older one and preserve the newer
494 * one.
496 cmp_res = compare_lebs(ubi, seb, pnum, vid_hdr);
497 if (cmp_res < 0)
498 return cmp_res;
500 if (cmp_res & 1) {
502 * This logical eraseblock is newer then the one
503 * found earlier.
505 err = validate_vid_hdr(vid_hdr, sv, pnum);
506 if (err)
507 return err;
509 if (cmp_res & 4)
510 err = add_to_list(si, seb->pnum, seb->ec,
511 &si->corr);
512 else
513 err = add_to_list(si, seb->pnum, seb->ec,
514 &si->erase);
515 if (err)
516 return err;
518 seb->ec = ec;
519 seb->pnum = pnum;
520 seb->scrub = ((cmp_res & 2) || bitflips);
521 seb->sqnum = sqnum;
522 seb->leb_ver = leb_ver;
524 if (sv->highest_lnum == lnum)
525 sv->last_data_size =
526 ubi32_to_cpu(vid_hdr->data_size);
528 return 0;
529 } else {
531 * This logical eraseblock is older then the one found
532 * previously.
534 if (cmp_res & 4)
535 return add_to_list(si, pnum, ec, &si->corr);
536 else
537 return add_to_list(si, pnum, ec, &si->erase);
542 * We've met this logical eraseblock for the first time, add it to the
543 * scanning information.
546 err = validate_vid_hdr(vid_hdr, sv, pnum);
547 if (err)
548 return err;
550 seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
551 if (!seb)
552 return -ENOMEM;
554 seb->ec = ec;
555 seb->pnum = pnum;
556 seb->lnum = lnum;
557 seb->sqnum = sqnum;
558 seb->scrub = bitflips;
559 seb->leb_ver = leb_ver;
561 if (sv->highest_lnum <= lnum) {
562 sv->highest_lnum = lnum;
563 sv->last_data_size = ubi32_to_cpu(vid_hdr->data_size);
566 if (si->max_sqnum < sqnum)
567 si->max_sqnum = sqnum;
569 sv->leb_count += 1;
570 rb_link_node(&seb->u.rb, parent, p);
571 rb_insert_color(&seb->u.rb, &sv->root);
572 return 0;
576 * ubi_scan_find_sv - find information about a particular volume in the
577 * scanning information.
578 * @si: scanning information
579 * @vol_id: the requested volume ID
581 * This function returns a pointer to the volume description or %NULL if there
582 * are no data about this volume in the scanning information.
584 struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
585 int vol_id)
587 struct ubi_scan_volume *sv;
588 struct rb_node *p = si->volumes.rb_node;
590 while (p) {
591 sv = rb_entry(p, struct ubi_scan_volume, rb);
593 if (vol_id == sv->vol_id)
594 return sv;
596 if (vol_id > sv->vol_id)
597 p = p->rb_left;
598 else
599 p = p->rb_right;
602 return NULL;
606 * ubi_scan_find_seb - find information about a particular logical
607 * eraseblock in the volume scanning information.
608 * @sv: a pointer to the volume scanning information
609 * @lnum: the requested logical eraseblock
611 * This function returns a pointer to the scanning logical eraseblock or %NULL
612 * if there are no data about it in the scanning volume information.
614 struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
615 int lnum)
617 struct ubi_scan_leb *seb;
618 struct rb_node *p = sv->root.rb_node;
620 while (p) {
621 seb = rb_entry(p, struct ubi_scan_leb, u.rb);
623 if (lnum == seb->lnum)
624 return seb;
626 if (lnum > seb->lnum)
627 p = p->rb_left;
628 else
629 p = p->rb_right;
632 return NULL;
636 * ubi_scan_rm_volume - delete scanning information about a volume.
637 * @si: scanning information
638 * @sv: the volume scanning information to delete
640 void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
642 struct rb_node *rb;
643 struct ubi_scan_leb *seb;
645 dbg_bld("remove scanning information about volume %d", sv->vol_id);
647 while ((rb = rb_first(&sv->root))) {
648 seb = rb_entry(rb, struct ubi_scan_leb, u.rb);
649 rb_erase(&seb->u.rb, &sv->root);
650 list_add_tail(&seb->u.list, &si->erase);
653 rb_erase(&sv->rb, &si->volumes);
654 kfree(sv);
655 si->vols_found -= 1;
659 * ubi_scan_erase_peb - erase a physical eraseblock.
660 * @ubi: UBI device description object
661 * @si: scanning information
662 * @pnum: physical eraseblock number to erase;
663 * @ec: erase counter value to write (%UBI_SCAN_UNKNOWN_EC if it is unknown)
665 * This function erases physical eraseblock 'pnum', and writes the erase
666 * counter header to it. This function should only be used on UBI device
667 * initialization stages, when the EBA unit had not been yet initialized. This
668 * function returns zero in case of success and a negative error code in case
669 * of failure.
671 int ubi_scan_erase_peb(const struct ubi_device *ubi,
672 const struct ubi_scan_info *si, int pnum, int ec)
674 int err;
675 struct ubi_ec_hdr *ec_hdr;
677 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
678 if (!ec_hdr)
679 return -ENOMEM;
681 if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
683 * Erase counter overflow. Upgrade UBI and use 64-bit
684 * erase counters internally.
686 ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec);
687 return -EINVAL;
690 ec_hdr->ec = cpu_to_ubi64(ec);
692 err = ubi_io_sync_erase(ubi, pnum, 0);
693 if (err < 0)
694 goto out_free;
696 err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
698 out_free:
699 kfree(ec_hdr);
700 return err;
704 * ubi_scan_get_free_peb - get a free physical eraseblock.
705 * @ubi: UBI device description object
706 * @si: scanning information
708 * This function returns a free physical eraseblock. It is supposed to be
709 * called on the UBI initialization stages when the wear-leveling unit is not
710 * initialized yet. This function picks a physical eraseblocks from one of the
711 * lists, writes the EC header if it is needed, and removes it from the list.
713 * This function returns scanning physical eraseblock information in case of
714 * success and an error code in case of failure.
716 struct ubi_scan_leb *ubi_scan_get_free_peb(const struct ubi_device *ubi,
717 struct ubi_scan_info *si)
719 int err = 0, i;
720 struct ubi_scan_leb *seb;
722 if (!list_empty(&si->free)) {
723 seb = list_entry(si->free.next, struct ubi_scan_leb, u.list);
724 list_del(&seb->u.list);
725 dbg_bld("return free PEB %d, EC %d", seb->pnum, seb->ec);
726 return seb;
729 for (i = 0; i < 2; i++) {
730 struct list_head *head;
731 struct ubi_scan_leb *tmp_seb;
733 if (i == 0)
734 head = &si->erase;
735 else
736 head = &si->corr;
739 * We try to erase the first physical eraseblock from the @head
740 * list and pick it if we succeed, or try to erase the
741 * next one if not. And so forth. We don't want to take care
742 * about bad eraseblocks here - they'll be handled later.
744 list_for_each_entry_safe(seb, tmp_seb, head, u.list) {
745 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
746 seb->ec = si->mean_ec;
748 err = ubi_scan_erase_peb(ubi, si, seb->pnum, seb->ec+1);
749 if (err)
750 continue;
752 seb->ec += 1;
753 list_del(&seb->u.list);
754 dbg_bld("return PEB %d, EC %d", seb->pnum, seb->ec);
755 return seb;
759 ubi_err("no eraseblocks found");
760 return ERR_PTR(-ENOSPC);
764 * process_eb - read UBI headers, check them and add corresponding data
765 * to the scanning information.
766 * @ubi: UBI device description object
767 * @si: scanning information
768 * @pnum: the physical eraseblock number
770 * This function returns a zero if the physical eraseblock was successfully
771 * handled and a negative error code in case of failure.
773 static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si, int pnum)
775 long long ec;
776 int err, bitflips = 0, vol_id, ec_corr = 0;
778 dbg_bld("scan PEB %d", pnum);
780 /* Skip bad physical eraseblocks */
781 err = ubi_io_is_bad(ubi, pnum);
782 if (err < 0)
783 return err;
784 else if (err) {
786 * FIXME: this is actually duty of the I/O unit to initialize
787 * this, but MTD does not provide enough information.
789 si->bad_peb_count += 1;
790 return 0;
793 err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
794 if (err < 0)
795 return err;
796 else if (err == UBI_IO_BITFLIPS)
797 bitflips = 1;
798 else if (err == UBI_IO_PEB_EMPTY)
799 return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, &si->erase);
800 else if (err == UBI_IO_BAD_EC_HDR) {
802 * We have to also look at the VID header, possibly it is not
803 * corrupted. Set %bitflips flag in order to make this PEB be
804 * moved and EC be re-created.
806 ec_corr = 1;
807 ec = UBI_SCAN_UNKNOWN_EC;
808 bitflips = 1;
811 si->is_empty = 0;
813 if (!ec_corr) {
814 /* Make sure UBI version is OK */
815 if (ech->version != UBI_VERSION) {
816 ubi_err("this UBI version is %d, image version is %d",
817 UBI_VERSION, (int)ech->version);
818 return -EINVAL;
821 ec = ubi64_to_cpu(ech->ec);
822 if (ec > UBI_MAX_ERASECOUNTER) {
824 * Erase counter overflow. The EC headers have 64 bits
825 * reserved, but we anyway make use of only 31 bit
826 * values, as this seems to be enough for any existing
827 * flash. Upgrade UBI and use 64-bit erase counters
828 * internally.
830 ubi_err("erase counter overflow, max is %d",
831 UBI_MAX_ERASECOUNTER);
832 ubi_dbg_dump_ec_hdr(ech);
833 return -EINVAL;
837 /* OK, we've done with the EC header, let's look at the VID header */
839 err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
840 if (err < 0)
841 return err;
842 else if (err == UBI_IO_BITFLIPS)
843 bitflips = 1;
844 else if (err == UBI_IO_BAD_VID_HDR ||
845 (err == UBI_IO_PEB_FREE && ec_corr)) {
846 /* VID header is corrupted */
847 err = add_to_list(si, pnum, ec, &si->corr);
848 if (err)
849 return err;
850 goto adjust_mean_ec;
851 } else if (err == UBI_IO_PEB_FREE) {
852 /* No VID header - the physical eraseblock is free */
853 err = add_to_list(si, pnum, ec, &si->free);
854 if (err)
855 return err;
856 goto adjust_mean_ec;
859 vol_id = ubi32_to_cpu(vidh->vol_id);
860 if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOL_ID) {
861 int lnum = ubi32_to_cpu(vidh->lnum);
863 /* Unsupported internal volume */
864 switch (vidh->compat) {
865 case UBI_COMPAT_DELETE:
866 ubi_msg("\"delete\" compatible internal volume %d:%d"
867 " found, remove it", vol_id, lnum);
868 err = add_to_list(si, pnum, ec, &si->corr);
869 if (err)
870 return err;
871 break;
873 case UBI_COMPAT_RO:
874 ubi_msg("read-only compatible internal volume %d:%d"
875 " found, switch to read-only mode",
876 vol_id, lnum);
877 ubi->ro_mode = 1;
878 break;
880 case UBI_COMPAT_PRESERVE:
881 ubi_msg("\"preserve\" compatible internal volume %d:%d"
882 " found", vol_id, lnum);
883 err = add_to_list(si, pnum, ec, &si->alien);
884 if (err)
885 return err;
886 si->alien_peb_count += 1;
887 return 0;
889 case UBI_COMPAT_REJECT:
890 ubi_err("incompatible internal volume %d:%d found",
891 vol_id, lnum);
892 return -EINVAL;
896 /* Both UBI headers seem to be fine */
897 err = ubi_scan_add_used(ubi, si, pnum, ec, vidh, bitflips);
898 if (err)
899 return err;
901 adjust_mean_ec:
902 if (!ec_corr) {
903 if (si->ec_sum + ec < ec) {
904 commit_to_mean_value(si);
905 si->ec_sum = 0;
906 si->ec_count = 0;
907 } else {
908 si->ec_sum += ec;
909 si->ec_count += 1;
912 if (ec > si->max_ec)
913 si->max_ec = ec;
914 if (ec < si->min_ec)
915 si->min_ec = ec;
918 return 0;
922 * ubi_scan - scan an MTD device.
923 * @ubi: UBI device description object
925 * This function does full scanning of an MTD device and returns complete
926 * information about it. In case of failure, an error code is returned.
928 struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
930 int err, pnum;
931 struct rb_node *rb1, *rb2;
932 struct ubi_scan_volume *sv;
933 struct ubi_scan_leb *seb;
934 struct ubi_scan_info *si;
936 si = kzalloc(sizeof(struct ubi_scan_info), GFP_KERNEL);
937 if (!si)
938 return ERR_PTR(-ENOMEM);
940 INIT_LIST_HEAD(&si->corr);
941 INIT_LIST_HEAD(&si->free);
942 INIT_LIST_HEAD(&si->erase);
943 INIT_LIST_HEAD(&si->alien);
944 si->volumes = RB_ROOT;
945 si->is_empty = 1;
947 err = -ENOMEM;
948 ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
949 if (!ech)
950 goto out_si;
952 vidh = ubi_zalloc_vid_hdr(ubi);
953 if (!vidh)
954 goto out_ech;
956 for (pnum = 0; pnum < ubi->peb_count; pnum++) {
957 cond_resched();
959 dbg_msg("process PEB %d", pnum);
960 err = process_eb(ubi, si, pnum);
961 if (err < 0)
962 goto out_vidh;
965 dbg_msg("scanning is finished");
967 /* Finish mean erase counter calculations */
968 if (si->ec_count)
969 commit_to_mean_value(si);
971 if (si->is_empty)
972 ubi_msg("empty MTD device detected");
975 * In case of unknown erase counter we use the mean erase counter
976 * value.
978 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
979 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
980 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
981 seb->ec = si->mean_ec;
984 list_for_each_entry(seb, &si->free, u.list) {
985 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
986 seb->ec = si->mean_ec;
989 list_for_each_entry(seb, &si->corr, u.list)
990 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
991 seb->ec = si->mean_ec;
993 list_for_each_entry(seb, &si->erase, u.list)
994 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
995 seb->ec = si->mean_ec;
997 err = paranoid_check_si(ubi, si);
998 if (err) {
999 if (err > 0)
1000 err = -EINVAL;
1001 goto out_vidh;
1004 ubi_free_vid_hdr(ubi, vidh);
1005 kfree(ech);
1007 return si;
1009 out_vidh:
1010 ubi_free_vid_hdr(ubi, vidh);
1011 out_ech:
1012 kfree(ech);
1013 out_si:
1014 ubi_scan_destroy_si(si);
1015 return ERR_PTR(err);
1019 * destroy_sv - free the scanning volume information
1020 * @sv: scanning volume information
1022 * This function destroys the volume RB-tree (@sv->root) and the scanning
1023 * volume information.
1025 static void destroy_sv(struct ubi_scan_volume *sv)
1027 struct ubi_scan_leb *seb;
1028 struct rb_node *this = sv->root.rb_node;
1030 while (this) {
1031 if (this->rb_left)
1032 this = this->rb_left;
1033 else if (this->rb_right)
1034 this = this->rb_right;
1035 else {
1036 seb = rb_entry(this, struct ubi_scan_leb, u.rb);
1037 this = rb_parent(this);
1038 if (this) {
1039 if (this->rb_left == &seb->u.rb)
1040 this->rb_left = NULL;
1041 else
1042 this->rb_right = NULL;
1045 kfree(seb);
1048 kfree(sv);
1052 * ubi_scan_destroy_si - destroy scanning information.
1053 * @si: scanning information
1055 void ubi_scan_destroy_si(struct ubi_scan_info *si)
1057 struct ubi_scan_leb *seb, *seb_tmp;
1058 struct ubi_scan_volume *sv;
1059 struct rb_node *rb;
1061 list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) {
1062 list_del(&seb->u.list);
1063 kfree(seb);
1065 list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {
1066 list_del(&seb->u.list);
1067 kfree(seb);
1069 list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {
1070 list_del(&seb->u.list);
1071 kfree(seb);
1073 list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {
1074 list_del(&seb->u.list);
1075 kfree(seb);
1078 /* Destroy the volume RB-tree */
1079 rb = si->volumes.rb_node;
1080 while (rb) {
1081 if (rb->rb_left)
1082 rb = rb->rb_left;
1083 else if (rb->rb_right)
1084 rb = rb->rb_right;
1085 else {
1086 sv = rb_entry(rb, struct ubi_scan_volume, rb);
1088 rb = rb_parent(rb);
1089 if (rb) {
1090 if (rb->rb_left == &sv->rb)
1091 rb->rb_left = NULL;
1092 else
1093 rb->rb_right = NULL;
1096 destroy_sv(sv);
1100 kfree(si);
1103 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1106 * paranoid_check_si - check if the scanning information is correct and
1107 * consistent.
1108 * @ubi: UBI device description object
1109 * @si: scanning information
1111 * This function returns zero if the scanning information is all right, %1 if
1112 * not and a negative error code if an error occurred.
1114 static int paranoid_check_si(const struct ubi_device *ubi,
1115 struct ubi_scan_info *si)
1117 int pnum, err, vols_found = 0;
1118 struct rb_node *rb1, *rb2;
1119 struct ubi_scan_volume *sv;
1120 struct ubi_scan_leb *seb, *last_seb;
1121 uint8_t *buf;
1124 * At first, check that scanning information is OK.
1126 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1127 int leb_count = 0;
1129 cond_resched();
1131 vols_found += 1;
1133 if (si->is_empty) {
1134 ubi_err("bad is_empty flag");
1135 goto bad_sv;
1138 if (sv->vol_id < 0 || sv->highest_lnum < 0 ||
1139 sv->leb_count < 0 || sv->vol_type < 0 || sv->used_ebs < 0 ||
1140 sv->data_pad < 0 || sv->last_data_size < 0) {
1141 ubi_err("negative values");
1142 goto bad_sv;
1145 if (sv->vol_id >= UBI_MAX_VOLUMES &&
1146 sv->vol_id < UBI_INTERNAL_VOL_START) {
1147 ubi_err("bad vol_id");
1148 goto bad_sv;
1151 if (sv->vol_id > si->highest_vol_id) {
1152 ubi_err("highest_vol_id is %d, but vol_id %d is there",
1153 si->highest_vol_id, sv->vol_id);
1154 goto out;
1157 if (sv->vol_type != UBI_DYNAMIC_VOLUME &&
1158 sv->vol_type != UBI_STATIC_VOLUME) {
1159 ubi_err("bad vol_type");
1160 goto bad_sv;
1163 if (sv->data_pad > ubi->leb_size / 2) {
1164 ubi_err("bad data_pad");
1165 goto bad_sv;
1168 last_seb = NULL;
1169 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1170 cond_resched();
1172 last_seb = seb;
1173 leb_count += 1;
1175 if (seb->pnum < 0 || seb->ec < 0) {
1176 ubi_err("negative values");
1177 goto bad_seb;
1180 if (seb->ec < si->min_ec) {
1181 ubi_err("bad si->min_ec (%d), %d found",
1182 si->min_ec, seb->ec);
1183 goto bad_seb;
1186 if (seb->ec > si->max_ec) {
1187 ubi_err("bad si->max_ec (%d), %d found",
1188 si->max_ec, seb->ec);
1189 goto bad_seb;
1192 if (seb->pnum >= ubi->peb_count) {
1193 ubi_err("too high PEB number %d, total PEBs %d",
1194 seb->pnum, ubi->peb_count);
1195 goto bad_seb;
1198 if (sv->vol_type == UBI_STATIC_VOLUME) {
1199 if (seb->lnum >= sv->used_ebs) {
1200 ubi_err("bad lnum or used_ebs");
1201 goto bad_seb;
1203 } else {
1204 if (sv->used_ebs != 0) {
1205 ubi_err("non-zero used_ebs");
1206 goto bad_seb;
1210 if (seb->lnum > sv->highest_lnum) {
1211 ubi_err("incorrect highest_lnum or lnum");
1212 goto bad_seb;
1216 if (sv->leb_count != leb_count) {
1217 ubi_err("bad leb_count, %d objects in the tree",
1218 leb_count);
1219 goto bad_sv;
1222 if (!last_seb)
1223 continue;
1225 seb = last_seb;
1227 if (seb->lnum != sv->highest_lnum) {
1228 ubi_err("bad highest_lnum");
1229 goto bad_seb;
1233 if (vols_found != si->vols_found) {
1234 ubi_err("bad si->vols_found %d, should be %d",
1235 si->vols_found, vols_found);
1236 goto out;
1239 /* Check that scanning information is correct */
1240 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1241 last_seb = NULL;
1242 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1243 int vol_type;
1245 cond_resched();
1247 last_seb = seb;
1249 err = ubi_io_read_vid_hdr(ubi, seb->pnum, vidh, 1);
1250 if (err && err != UBI_IO_BITFLIPS) {
1251 ubi_err("VID header is not OK (%d)", err);
1252 if (err > 0)
1253 err = -EIO;
1254 return err;
1257 vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
1258 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
1259 if (sv->vol_type != vol_type) {
1260 ubi_err("bad vol_type");
1261 goto bad_vid_hdr;
1264 if (seb->sqnum != ubi64_to_cpu(vidh->sqnum)) {
1265 ubi_err("bad sqnum %llu", seb->sqnum);
1266 goto bad_vid_hdr;
1269 if (sv->vol_id != ubi32_to_cpu(vidh->vol_id)) {
1270 ubi_err("bad vol_id %d", sv->vol_id);
1271 goto bad_vid_hdr;
1274 if (sv->compat != vidh->compat) {
1275 ubi_err("bad compat %d", vidh->compat);
1276 goto bad_vid_hdr;
1279 if (seb->lnum != ubi32_to_cpu(vidh->lnum)) {
1280 ubi_err("bad lnum %d", seb->lnum);
1281 goto bad_vid_hdr;
1284 if (sv->used_ebs != ubi32_to_cpu(vidh->used_ebs)) {
1285 ubi_err("bad used_ebs %d", sv->used_ebs);
1286 goto bad_vid_hdr;
1289 if (sv->data_pad != ubi32_to_cpu(vidh->data_pad)) {
1290 ubi_err("bad data_pad %d", sv->data_pad);
1291 goto bad_vid_hdr;
1294 if (seb->leb_ver != ubi32_to_cpu(vidh->leb_ver)) {
1295 ubi_err("bad leb_ver %u", seb->leb_ver);
1296 goto bad_vid_hdr;
1300 if (!last_seb)
1301 continue;
1303 if (sv->highest_lnum != ubi32_to_cpu(vidh->lnum)) {
1304 ubi_err("bad highest_lnum %d", sv->highest_lnum);
1305 goto bad_vid_hdr;
1308 if (sv->last_data_size != ubi32_to_cpu(vidh->data_size)) {
1309 ubi_err("bad last_data_size %d", sv->last_data_size);
1310 goto bad_vid_hdr;
1315 * Make sure that all the physical eraseblocks are in one of the lists
1316 * or trees.
1318 buf = kmalloc(ubi->peb_count, GFP_KERNEL);
1319 if (!buf)
1320 return -ENOMEM;
1322 memset(buf, 1, ubi->peb_count);
1323 for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1324 err = ubi_io_is_bad(ubi, pnum);
1325 if (err < 0) {
1326 kfree(buf);
1327 return err;
1329 else if (err)
1330 buf[pnum] = 0;
1333 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb)
1334 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
1335 buf[seb->pnum] = 0;
1337 list_for_each_entry(seb, &si->free, u.list)
1338 buf[seb->pnum] = 0;
1340 list_for_each_entry(seb, &si->corr, u.list)
1341 buf[seb->pnum] = 0;
1343 list_for_each_entry(seb, &si->erase, u.list)
1344 buf[seb->pnum] = 0;
1346 list_for_each_entry(seb, &si->alien, u.list)
1347 buf[seb->pnum] = 0;
1349 err = 0;
1350 for (pnum = 0; pnum < ubi->peb_count; pnum++)
1351 if (buf[pnum]) {
1352 ubi_err("PEB %d is not referred", pnum);
1353 err = 1;
1356 kfree(buf);
1357 if (err)
1358 goto out;
1359 return 0;
1361 bad_seb:
1362 ubi_err("bad scanning information about LEB %d", seb->lnum);
1363 ubi_dbg_dump_seb(seb, 0);
1364 ubi_dbg_dump_sv(sv);
1365 goto out;
1367 bad_sv:
1368 ubi_err("bad scanning information about volume %d", sv->vol_id);
1369 ubi_dbg_dump_sv(sv);
1370 goto out;
1372 bad_vid_hdr:
1373 ubi_err("bad scanning information about volume %d", sv->vol_id);
1374 ubi_dbg_dump_sv(sv);
1375 ubi_dbg_dump_vid_hdr(vidh);
1377 out:
1378 ubi_dbg_dump_stack();
1379 return 1;
1382 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */