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 sub-system.
24 * This sub-system 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 * Scanned 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.
42 * UBI tries to distinguish between 2 types of corruptions.
43 * 1. Corruptions caused by power cuts. These are harmless and expected
44 * corruptions and UBI tries to handle them gracefully, without printing too
45 * many warnings and error messages. The idea is that we do not lose
46 * important data in these case - we may lose only the data which was being
47 * written to the media just before the power cut happened, and the upper
48 * layers (e.g., UBIFS) are supposed to handle these situations. UBI puts
49 * these PEBs to the head of the @erase list and they are scheduled for
52 * 2. Unexpected corruptions which are not caused by power cuts. During
53 * scanning, such PEBs are put to the @corr list and UBI preserves them.
54 * Obviously, this lessens the amount of available PEBs, and if at some
55 * point UBI runs out of free PEBs, it switches to R/O mode. UBI also loudly
56 * informs about such PEBs every time the MTD device is attached.
58 * However, it is difficult to reliably distinguish between these types of
59 * corruptions and UBI's strategy is as follows. UBI assumes (2.) if the VID
60 * header is corrupted and the data area does not contain all 0xFFs, and there
61 * were not bit-flips or integrity errors while reading the data area. Otherwise
62 * UBI assumes (1.). The assumptions are:
63 * o if the data area contains only 0xFFs, there is no data, and it is safe
64 * to just erase this PEB.
65 * o if the data area has bit-flips and data integrity errors (ECC errors on
66 * NAND), it is probably a PEB which was being erased when power cut
70 #include <linux/err.h>
71 #include <linux/slab.h>
72 #include <linux/crc32.h>
73 #include <linux/math64.h>
74 #include <linux/random.h>
77 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
78 static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si);
80 #define paranoid_check_si(ubi, si) 0
83 /* Temporary variables used during scanning */
84 static struct ubi_ec_hdr *ech;
85 static struct ubi_vid_hdr *vidh;
88 * add_to_list - add physical eraseblock to a list.
89 * @si: scanning information
90 * @pnum: physical eraseblock number to add
91 * @ec: erase counter of the physical eraseblock
92 * @to_head: if not zero, add to the head of the list
93 * @list: the list to add to
95 * This function adds physical eraseblock @pnum to free, erase, or alien lists.
96 * If @to_head is not zero, PEB will be added to the head of the list, which
97 * basically means it will be processed first later. E.g., we add corrupted
98 * PEBs (corrupted due to power cuts) to the head of the erase list to make
99 * sure we erase them first and get rid of corruptions ASAP. This function
100 * returns zero in case of success and a negative error code in case of
103 static int add_to_list(struct ubi_scan_info *si, int pnum, int ec, int to_head,
104 struct list_head *list)
106 struct ubi_scan_leb *seb;
108 if (list == &si->free) {
109 dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
110 } else if (list == &si->erase) {
111 dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
112 } else if (list == &si->alien) {
113 dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
114 si->alien_peb_count += 1;
118 seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
125 list_add(&seb->u.list, list);
127 list_add_tail(&seb->u.list, list);
132 * add_corrupted - add a corrupted physical eraseblock.
133 * @si: scanning information
134 * @pnum: physical eraseblock number to add
135 * @ec: erase counter of the physical eraseblock
137 * This function adds corrupted physical eraseblock @pnum to the 'corr' list.
138 * The corruption was presumably not caused by a power cut. Returns zero in
139 * case of success and a negative error code in case of failure.
141 static int add_corrupted(struct ubi_scan_info *si, int pnum, int ec)
143 struct ubi_scan_leb *seb;
145 dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
147 seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
151 si->corr_peb_count += 1;
154 list_add(&seb->u.list, &si->corr);
159 * validate_vid_hdr - check volume identifier header.
160 * @vid_hdr: the volume identifier header to check
161 * @sv: information about the volume this logical eraseblock belongs to
162 * @pnum: physical eraseblock number the VID header came from
164 * This function checks that data stored in @vid_hdr is consistent. Returns
165 * non-zero if an inconsistency was found and zero if not.
167 * Note, UBI does sanity check of everything it reads from the flash media.
168 * Most of the checks are done in the I/O sub-system. Here we check that the
169 * information in the VID header is consistent to the information in other VID
170 * headers of the same volume.
172 static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr,
173 const struct ubi_scan_volume *sv, int pnum)
175 int vol_type = vid_hdr->vol_type;
176 int vol_id = be32_to_cpu(vid_hdr->vol_id);
177 int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
178 int data_pad = be32_to_cpu(vid_hdr->data_pad);
180 if (sv->leb_count != 0) {
184 * This is not the first logical eraseblock belonging to this
185 * volume. Ensure that the data in its VID header is consistent
186 * to the data in previous logical eraseblock headers.
189 if (vol_id != sv->vol_id) {
190 dbg_err("inconsistent vol_id");
194 if (sv->vol_type == UBI_STATIC_VOLUME)
195 sv_vol_type = UBI_VID_STATIC;
197 sv_vol_type = UBI_VID_DYNAMIC;
199 if (vol_type != sv_vol_type) {
200 dbg_err("inconsistent vol_type");
204 if (used_ebs != sv->used_ebs) {
205 dbg_err("inconsistent used_ebs");
209 if (data_pad != sv->data_pad) {
210 dbg_err("inconsistent data_pad");
218 ubi_err("inconsistent VID header at PEB %d", pnum);
219 ubi_dbg_dump_vid_hdr(vid_hdr);
225 * add_volume - add volume to the scanning information.
226 * @si: scanning information
227 * @vol_id: ID of the volume to add
228 * @pnum: physical eraseblock number
229 * @vid_hdr: volume identifier header
231 * If the volume corresponding to the @vid_hdr logical eraseblock is already
232 * present in the scanning information, this function does nothing. Otherwise
233 * it adds corresponding volume to the scanning information. Returns a pointer
234 * to the scanning volume object in case of success and a negative error code
235 * in case of failure.
237 static struct ubi_scan_volume *add_volume(struct ubi_scan_info *si, int vol_id,
239 const struct ubi_vid_hdr *vid_hdr)
241 struct ubi_scan_volume *sv;
242 struct rb_node **p = &si->volumes.rb_node, *parent = NULL;
244 ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
246 /* Walk the volume RB-tree to look if this volume is already present */
249 sv = rb_entry(parent, struct ubi_scan_volume, rb);
251 if (vol_id == sv->vol_id)
254 if (vol_id > sv->vol_id)
260 /* The volume is absent - add it */
261 sv = kmalloc(sizeof(struct ubi_scan_volume), GFP_KERNEL);
263 return ERR_PTR(-ENOMEM);
265 sv->highest_lnum = sv->leb_count = 0;
268 sv->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
269 sv->data_pad = be32_to_cpu(vid_hdr->data_pad);
270 sv->compat = vid_hdr->compat;
271 sv->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
273 if (vol_id > si->highest_vol_id)
274 si->highest_vol_id = vol_id;
276 rb_link_node(&sv->rb, parent, p);
277 rb_insert_color(&sv->rb, &si->volumes);
279 dbg_bld("added volume %d", vol_id);
284 * compare_lebs - find out which logical eraseblock is newer.
285 * @ubi: UBI device description object
286 * @seb: first logical eraseblock to compare
287 * @pnum: physical eraseblock number of the second logical eraseblock to
289 * @vid_hdr: volume identifier header of the second logical eraseblock
291 * This function compares 2 copies of a LEB and informs which one is newer. In
292 * case of success this function returns a positive value, in case of failure, a
293 * negative error code is returned. The success return codes use the following
295 * o bit 0 is cleared: the first PEB (described by @seb) is newer than the
296 * second PEB (described by @pnum and @vid_hdr);
297 * o bit 0 is set: the second PEB is newer;
298 * o bit 1 is cleared: no bit-flips were detected in the newer LEB;
299 * o bit 1 is set: bit-flips were detected in the newer LEB;
300 * o bit 2 is cleared: the older LEB is not corrupted;
301 * o bit 2 is set: the older LEB is corrupted.
303 static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
304 int pnum, const struct ubi_vid_hdr *vid_hdr)
307 int len, err, second_is_newer, bitflips = 0, corrupted = 0;
308 uint32_t data_crc, crc;
309 struct ubi_vid_hdr *vh = NULL;
310 unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
312 if (sqnum2 == seb->sqnum) {
314 * This must be a really ancient UBI image which has been
315 * created before sequence numbers support has been added. At
316 * that times we used 32-bit LEB versions stored in logical
317 * eraseblocks. That was before UBI got into mainline. We do not
318 * support these images anymore. Well, those images still work,
319 * but only if no unclean reboots happened.
321 ubi_err("unsupported on-flash UBI format\n");
325 /* Obviously the LEB with lower sequence counter is older */
326 second_is_newer = !!(sqnum2 > seb->sqnum);
329 * Now we know which copy is newer. If the copy flag of the PEB with
330 * newer version is not set, then we just return, otherwise we have to
331 * check data CRC. For the second PEB we already have the VID header,
332 * for the first one - we'll need to re-read it from flash.
334 * Note: this may be optimized so that we wouldn't read twice.
337 if (second_is_newer) {
338 if (!vid_hdr->copy_flag) {
339 /* It is not a copy, so it is newer */
340 dbg_bld("second PEB %d is newer, copy_flag is unset",
345 if (!seb->copy_flag) {
346 /* It is not a copy, so it is newer */
347 dbg_bld("first PEB %d is newer, copy_flag is unset",
349 return bitflips << 1;
352 vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
357 err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
359 if (err == UBI_IO_BITFLIPS)
362 dbg_err("VID of PEB %d header is bad, but it "
363 "was OK earlier, err %d", pnum, err);
374 /* Read the data of the copy and check the CRC */
376 len = be32_to_cpu(vid_hdr->data_size);
383 err = ubi_io_read_data(ubi, buf, pnum, 0, len);
384 if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
387 data_crc = be32_to_cpu(vid_hdr->data_crc);
388 crc = crc32(UBI_CRC32_INIT, buf, len);
389 if (crc != data_crc) {
390 dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
391 pnum, crc, data_crc);
394 second_is_newer = !second_is_newer;
396 dbg_bld("PEB %d CRC is OK", pnum);
401 ubi_free_vid_hdr(ubi, vh);
404 dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
406 dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
408 return second_is_newer | (bitflips << 1) | (corrupted << 2);
413 ubi_free_vid_hdr(ubi, vh);
418 * ubi_scan_add_used - add physical eraseblock to the scanning information.
419 * @ubi: UBI device description object
420 * @si: scanning information
421 * @pnum: the physical eraseblock number
423 * @vid_hdr: the volume identifier header
424 * @bitflips: if bit-flips were detected when this physical eraseblock was read
426 * This function adds information about a used physical eraseblock to the
427 * 'used' tree of the corresponding volume. The function is rather complex
428 * because it has to handle cases when this is not the first physical
429 * eraseblock belonging to the same logical eraseblock, and the newer one has
430 * to be picked, while the older one has to be dropped. This function returns
431 * zero in case of success and a negative error code in case of failure.
433 int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
434 int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
437 int err, vol_id, lnum;
438 unsigned long long sqnum;
439 struct ubi_scan_volume *sv;
440 struct ubi_scan_leb *seb;
441 struct rb_node **p, *parent = NULL;
443 vol_id = be32_to_cpu(vid_hdr->vol_id);
444 lnum = be32_to_cpu(vid_hdr->lnum);
445 sqnum = be64_to_cpu(vid_hdr->sqnum);
447 dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d",
448 pnum, vol_id, lnum, ec, sqnum, bitflips);
450 sv = add_volume(si, vol_id, pnum, vid_hdr);
454 if (si->max_sqnum < sqnum)
455 si->max_sqnum = sqnum;
458 * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
459 * if this is the first instance of this logical eraseblock or not.
461 p = &sv->root.rb_node;
466 seb = rb_entry(parent, struct ubi_scan_leb, u.rb);
467 if (lnum != seb->lnum) {
468 if (lnum < seb->lnum)
476 * There is already a physical eraseblock describing the same
477 * logical eraseblock present.
480 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, "
481 "EC %d", seb->pnum, seb->sqnum, seb->ec);
484 * Make sure that the logical eraseblocks have different
485 * sequence numbers. Otherwise the image is bad.
487 * However, if the sequence number is zero, we assume it must
488 * be an ancient UBI image from the era when UBI did not have
489 * sequence numbers. We still can attach these images, unless
490 * there is a need to distinguish between old and new
491 * eraseblocks, in which case we'll refuse the image in
492 * 'compare_lebs()'. In other words, we attach old clean
493 * images, but refuse attaching old images with duplicated
494 * logical eraseblocks because there was an unclean reboot.
496 if (seb->sqnum == sqnum && sqnum != 0) {
497 ubi_err("two LEBs with same sequence number %llu",
499 ubi_dbg_dump_seb(seb, 0);
500 ubi_dbg_dump_vid_hdr(vid_hdr);
505 * Now we have to drop the older one and preserve the newer
508 cmp_res = compare_lebs(ubi, seb, pnum, vid_hdr);
514 * This logical eraseblock is newer than the one
517 err = validate_vid_hdr(vid_hdr, sv, pnum);
521 err = add_to_list(si, seb->pnum, seb->ec, cmp_res & 4,
528 seb->scrub = ((cmp_res & 2) || bitflips);
529 seb->copy_flag = vid_hdr->copy_flag;
532 if (sv->highest_lnum == lnum)
534 be32_to_cpu(vid_hdr->data_size);
539 * This logical eraseblock is older than the one found
542 return add_to_list(si, pnum, ec, cmp_res & 4,
548 * We've met this logical eraseblock for the first time, add it to the
549 * scanning information.
552 err = validate_vid_hdr(vid_hdr, sv, pnum);
556 seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
563 seb->scrub = bitflips;
564 seb->copy_flag = vid_hdr->copy_flag;
567 if (sv->highest_lnum <= lnum) {
568 sv->highest_lnum = lnum;
569 sv->last_data_size = be32_to_cpu(vid_hdr->data_size);
573 rb_link_node(&seb->u.rb, parent, p);
574 rb_insert_color(&seb->u.rb, &sv->root);
579 * ubi_scan_find_sv - find volume in the scanning information.
580 * @si: scanning information
581 * @vol_id: the requested volume ID
583 * This function returns a pointer to the volume description or %NULL if there
584 * are no data about this volume in the scanning information.
586 struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
589 struct ubi_scan_volume *sv;
590 struct rb_node *p = si->volumes.rb_node;
593 sv = rb_entry(p, struct ubi_scan_volume, rb);
595 if (vol_id == sv->vol_id)
598 if (vol_id > sv->vol_id)
608 * ubi_scan_find_seb - find LEB in the volume scanning information.
609 * @sv: a pointer to the volume scanning information
610 * @lnum: the requested logical eraseblock
612 * This function returns a pointer to the scanning logical eraseblock or %NULL
613 * if there are no data about it in the scanning volume information.
615 struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
618 struct ubi_scan_leb *seb;
619 struct rb_node *p = sv->root.rb_node;
622 seb = rb_entry(p, struct ubi_scan_leb, u.rb);
624 if (lnum == seb->lnum)
627 if (lnum > seb->lnum)
637 * ubi_scan_rm_volume - delete scanning information about a volume.
638 * @si: scanning information
639 * @sv: the volume scanning information to delete
641 void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
644 struct ubi_scan_leb *seb;
646 dbg_bld("remove scanning information about volume %d", sv->vol_id);
648 while ((rb = rb_first(&sv->root))) {
649 seb = rb_entry(rb, struct ubi_scan_leb, u.rb);
650 rb_erase(&seb->u.rb, &sv->root);
651 list_add_tail(&seb->u.list, &si->erase);
654 rb_erase(&sv->rb, &si->volumes);
660 * ubi_scan_erase_peb - erase a physical eraseblock.
661 * @ubi: UBI device description object
662 * @si: scanning information
663 * @pnum: physical eraseblock number to erase;
664 * @ec: erase counter value to write (%UBI_SCAN_UNKNOWN_EC if it is unknown)
666 * This function erases physical eraseblock 'pnum', and writes the erase
667 * counter header to it. This function should only be used on UBI device
668 * initialization stages, when the EBA sub-system had not been yet initialized.
669 * This function returns zero in case of success and a negative error code in
672 int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
676 struct ubi_ec_hdr *ec_hdr;
678 if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
680 * Erase counter overflow. Upgrade UBI and use 64-bit
681 * erase counters internally.
683 ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec);
687 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
691 ec_hdr->ec = cpu_to_be64(ec);
693 err = ubi_io_sync_erase(ubi, pnum, 0);
697 err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
705 * ubi_scan_get_free_peb - get a free physical eraseblock.
706 * @ubi: UBI device description object
707 * @si: scanning information
709 * This function returns a free physical eraseblock. It is supposed to be
710 * called on the UBI initialization stages when the wear-leveling sub-system is
711 * not initialized yet. This function picks a physical eraseblocks from one of
712 * the lists, writes the EC header if it is needed, and removes it from the
715 * This function returns scanning physical eraseblock information in case of
716 * success and an error code in case of failure.
718 struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
719 struct ubi_scan_info *si)
722 struct ubi_scan_leb *seb, *tmp_seb;
724 if (!list_empty(&si->free)) {
725 seb = list_entry(si->free.next, struct ubi_scan_leb, u.list);
726 list_del(&seb->u.list);
727 dbg_bld("return free PEB %d, EC %d", seb->pnum, seb->ec);
732 * We try to erase the first physical eraseblock from the erase list
733 * and pick it if we succeed, or try to erase the next one if not. And
734 * so forth. We don't want to take care about bad eraseblocks here -
735 * they'll be handled later.
737 list_for_each_entry_safe(seb, tmp_seb, &si->erase, u.list) {
738 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
739 seb->ec = si->mean_ec;
741 err = ubi_scan_erase_peb(ubi, si, seb->pnum, seb->ec+1);
746 list_del(&seb->u.list);
747 dbg_bld("return PEB %d, EC %d", seb->pnum, seb->ec);
751 ubi_err("no free eraseblocks");
752 return ERR_PTR(-ENOSPC);
756 * check_corruption - check the data area of PEB.
757 * @ubi: UBI device description object
758 * @vid_hrd: the (corrupted) VID header of this PEB
759 * @pnum: the physical eraseblock number to check
761 * This is a helper function which is used to distinguish between VID header
762 * corruptions caused by power cuts and other reasons. If the PEB contains only
763 * 0xFF bytes in the data area, the VID header is most probably corrupted
764 * because of a power cut (%0 is returned in this case). Otherwise, it was
765 * probably corrupted for some other reasons (%1 is returned in this case). A
766 * negative error code is returned if a read error occurred.
768 * If the corruption reason was a power cut, UBI can safely erase this PEB.
769 * Otherwise, it should preserve it to avoid possibly destroying important
772 static int check_corruption(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr,
777 mutex_lock(&ubi->buf_mutex);
778 memset(ubi->peb_buf1, 0x00, ubi->leb_size);
780 err = ubi_io_read(ubi, ubi->peb_buf1, pnum, ubi->leb_start,
782 if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
784 * Bit-flips or integrity errors while reading the data area.
785 * It is difficult to say for sure what type of corruption is
786 * this, but presumably a power cut happened while this PEB was
787 * erased, so it became unstable and corrupted, and should be
797 if (ubi_check_pattern(ubi->peb_buf1, 0xFF, ubi->leb_size))
800 ubi_err("PEB %d contains corrupted VID header, and the data does not "
801 "contain all 0xFF, this may be a non-UBI PEB or a severe VID "
802 "header corruption which requires manual inspection", pnum);
803 ubi_dbg_dump_vid_hdr(vid_hdr);
804 dbg_msg("hexdump of PEB %d offset %d, length %d",
805 pnum, ubi->leb_start, ubi->leb_size);
806 ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
807 ubi->peb_buf1, ubi->leb_size, 1);
811 mutex_unlock(&ubi->buf_mutex);
816 * process_eb - read, check UBI headers, and add them to scanning information.
817 * @ubi: UBI device description object
818 * @si: scanning information
819 * @pnum: the physical eraseblock number
821 * This function returns a zero if the physical eraseblock was successfully
822 * handled and a negative error code in case of failure.
824 static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
827 long long uninitialized_var(ec);
828 int err, bitflips = 0, vol_id, ec_err = 0;
830 dbg_bld("scan PEB %d", pnum);
832 /* Skip bad physical eraseblocks */
833 err = ubi_io_is_bad(ubi, pnum);
838 * FIXME: this is actually duty of the I/O sub-system to
839 * initialize this, but MTD does not provide enough
842 si->bad_peb_count += 1;
846 err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
852 case UBI_IO_BITFLIPS:
856 si->empty_peb_count += 1;
857 return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 0,
859 case UBI_IO_FF_BITFLIPS:
860 si->empty_peb_count += 1;
861 return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 1,
863 case UBI_IO_BAD_HDR_EBADMSG:
866 * We have to also look at the VID header, possibly it is not
867 * corrupted. Set %bitflips flag in order to make this PEB be
868 * moved and EC be re-created.
871 ec = UBI_SCAN_UNKNOWN_EC;
875 ubi_err("'ubi_io_read_ec_hdr()' returned unknown code %d", err);
882 /* Make sure UBI version is OK */
883 if (ech->version != UBI_VERSION) {
884 ubi_err("this UBI version is %d, image version is %d",
885 UBI_VERSION, (int)ech->version);
889 ec = be64_to_cpu(ech->ec);
890 if (ec > UBI_MAX_ERASECOUNTER) {
892 * Erase counter overflow. The EC headers have 64 bits
893 * reserved, but we anyway make use of only 31 bit
894 * values, as this seems to be enough for any existing
895 * flash. Upgrade UBI and use 64-bit erase counters
898 ubi_err("erase counter overflow, max is %d",
899 UBI_MAX_ERASECOUNTER);
900 ubi_dbg_dump_ec_hdr(ech);
905 * Make sure that all PEBs have the same image sequence number.
906 * This allows us to detect situations when users flash UBI
907 * images incorrectly, so that the flash has the new UBI image
908 * and leftovers from the old one. This feature was added
909 * relatively recently, and the sequence number was always
910 * zero, because old UBI implementations always set it to zero.
911 * For this reasons, we do not panic if some PEBs have zero
912 * sequence number, while other PEBs have non-zero sequence
915 image_seq = be32_to_cpu(ech->image_seq);
916 if (!ubi->image_seq && image_seq)
917 ubi->image_seq = image_seq;
918 if (ubi->image_seq && image_seq &&
919 ubi->image_seq != image_seq) {
920 ubi_err("bad image sequence number %d in PEB %d, "
921 "expected %d", image_seq, pnum, ubi->image_seq);
922 ubi_dbg_dump_ec_hdr(ech);
927 /* OK, we've done with the EC header, let's look at the VID header */
929 err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
935 case UBI_IO_BITFLIPS:
938 case UBI_IO_BAD_HDR_EBADMSG:
939 if (ec_err == UBI_IO_BAD_HDR_EBADMSG)
941 * Both EC and VID headers are corrupted and were read
942 * with data integrity error, probably this is a bad
943 * PEB, bit it is not marked as bad yet. This may also
944 * be a result of power cut during erasure.
946 si->maybe_bad_peb_count += 1;
950 * Both headers are corrupted. There is a possibility
951 * that this a valid UBI PEB which has corresponding
952 * LEB, but the headers are corrupted. However, it is
953 * impossible to distinguish it from a PEB which just
954 * contains garbage because of a power cut during erase
955 * operation. So we just schedule this PEB for erasure.
957 * Besides, in case of NOR flash, we deliberatly
958 * corrupt both headers because NOR flash erasure is
959 * slow and can start from the end.
964 * The EC was OK, but the VID header is corrupted. We
965 * have to check what is in the data area.
967 err = check_corruption(ubi, vidh, pnum);
972 /* This corruption is caused by a power cut */
973 err = add_to_list(si, pnum, ec, 1, &si->erase);
975 /* This is an unexpected corruption */
976 err = add_corrupted(si, pnum, ec);
980 case UBI_IO_FF_BITFLIPS:
981 err = add_to_list(si, pnum, ec, 1, &si->erase);
987 err = add_to_list(si, pnum, ec, 1, &si->erase);
989 err = add_to_list(si, pnum, ec, 0, &si->free);
994 ubi_err("'ubi_io_read_vid_hdr()' returned unknown code %d",
999 vol_id = be32_to_cpu(vidh->vol_id);
1000 if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) {
1001 int lnum = be32_to_cpu(vidh->lnum);
1003 /* Unsupported internal volume */
1004 switch (vidh->compat) {
1005 case UBI_COMPAT_DELETE:
1006 ubi_msg("\"delete\" compatible internal volume %d:%d"
1007 " found, will remove it", vol_id, lnum);
1008 err = add_to_list(si, pnum, ec, 1, &si->erase);
1014 ubi_msg("read-only compatible internal volume %d:%d"
1015 " found, switch to read-only mode",
1020 case UBI_COMPAT_PRESERVE:
1021 ubi_msg("\"preserve\" compatible internal volume %d:%d"
1022 " found", vol_id, lnum);
1023 err = add_to_list(si, pnum, ec, 0, &si->alien);
1028 case UBI_COMPAT_REJECT:
1029 ubi_err("incompatible internal volume %d:%d found",
1036 ubi_warn("valid VID header but corrupted EC header at PEB %d",
1038 err = ubi_scan_add_used(ubi, si, pnum, ec, vidh, bitflips);
1046 if (ec > si->max_ec)
1048 if (ec < si->min_ec)
1056 * check_what_we_have - check what PEB were found by scanning.
1057 * @ubi: UBI device description object
1058 * @si: scanning information
1060 * This is a helper function which takes a look what PEBs were found by
1061 * scanning, and decides whether the flash is empty and should be formatted and
1062 * whether there are too many corrupted PEBs and we should not attach this
1063 * MTD device. Returns zero if we should proceed with attaching the MTD device,
1064 * and %-EINVAL if we should not.
1066 static int check_what_we_have(struct ubi_device *ubi, struct ubi_scan_info *si)
1068 struct ubi_scan_leb *seb;
1069 int max_corr, peb_count;
1071 peb_count = ubi->peb_count - si->bad_peb_count - si->alien_peb_count;
1072 max_corr = peb_count / 20 ?: 8;
1075 * Few corrupted PEBs is not a problem and may be just a result of
1076 * unclean reboots. However, many of them may indicate some problems
1077 * with the flash HW or driver.
1079 if (si->corr_peb_count) {
1080 ubi_err("%d PEBs are corrupted and preserved",
1081 si->corr_peb_count);
1082 printk(KERN_ERR "Corrupted PEBs are:");
1083 list_for_each_entry(seb, &si->corr, u.list)
1084 printk(KERN_CONT " %d", seb->pnum);
1085 printk(KERN_CONT "\n");
1088 * If too many PEBs are corrupted, we refuse attaching,
1089 * otherwise, only print a warning.
1091 if (si->corr_peb_count >= max_corr) {
1092 ubi_err("too many corrupted PEBs, refusing this device");
1097 if (si->empty_peb_count + si->maybe_bad_peb_count == peb_count) {
1099 * All PEBs are empty, or almost all - a couple PEBs look like
1100 * they may be bad PEBs which were not marked as bad yet.
1102 * This piece of code basically tries to distinguish between
1103 * the following situations:
1105 * 1. Flash is empty, but there are few bad PEBs, which are not
1106 * marked as bad so far, and which were read with error. We
1107 * want to go ahead and format this flash. While formatting,
1108 * the faulty PEBs will probably be marked as bad.
1110 * 2. Flash contains non-UBI data and we do not want to format
1111 * it and destroy possibly important information.
1113 if (si->maybe_bad_peb_count <= 2) {
1115 ubi_msg("empty MTD device detected");
1116 get_random_bytes(&ubi->image_seq,
1117 sizeof(ubi->image_seq));
1119 ubi_err("MTD device is not UBI-formatted and possibly "
1120 "contains non-UBI data - refusing it");
1130 * ubi_scan - scan an MTD device.
1131 * @ubi: UBI device description object
1133 * This function does full scanning of an MTD device and returns complete
1134 * information about it. In case of failure, an error code is returned.
1136 struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
1139 struct rb_node *rb1, *rb2;
1140 struct ubi_scan_volume *sv;
1141 struct ubi_scan_leb *seb;
1142 struct ubi_scan_info *si;
1144 si = kzalloc(sizeof(struct ubi_scan_info), GFP_KERNEL);
1146 return ERR_PTR(-ENOMEM);
1148 INIT_LIST_HEAD(&si->corr);
1149 INIT_LIST_HEAD(&si->free);
1150 INIT_LIST_HEAD(&si->erase);
1151 INIT_LIST_HEAD(&si->alien);
1152 si->volumes = RB_ROOT;
1155 ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1159 vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
1163 for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1166 dbg_gen("process PEB %d", pnum);
1167 err = process_eb(ubi, si, pnum);
1172 dbg_msg("scanning is finished");
1174 /* Calculate mean erase counter */
1176 si->mean_ec = div_u64(si->ec_sum, si->ec_count);
1178 err = check_what_we_have(ubi, si);
1183 * In case of unknown erase counter we use the mean erase counter
1186 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1187 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
1188 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1189 seb->ec = si->mean_ec;
1192 list_for_each_entry(seb, &si->free, u.list) {
1193 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1194 seb->ec = si->mean_ec;
1197 list_for_each_entry(seb, &si->corr, u.list)
1198 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1199 seb->ec = si->mean_ec;
1201 list_for_each_entry(seb, &si->erase, u.list)
1202 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1203 seb->ec = si->mean_ec;
1205 err = paranoid_check_si(ubi, si);
1209 ubi_free_vid_hdr(ubi, vidh);
1215 ubi_free_vid_hdr(ubi, vidh);
1219 ubi_scan_destroy_si(si);
1220 return ERR_PTR(err);
1224 * destroy_sv - free the scanning volume information
1225 * @sv: scanning volume information
1227 * This function destroys the volume RB-tree (@sv->root) and the scanning
1228 * volume information.
1230 static void destroy_sv(struct ubi_scan_volume *sv)
1232 struct ubi_scan_leb *seb;
1233 struct rb_node *this = sv->root.rb_node;
1237 this = this->rb_left;
1238 else if (this->rb_right)
1239 this = this->rb_right;
1241 seb = rb_entry(this, struct ubi_scan_leb, u.rb);
1242 this = rb_parent(this);
1244 if (this->rb_left == &seb->u.rb)
1245 this->rb_left = NULL;
1247 this->rb_right = NULL;
1257 * ubi_scan_destroy_si - destroy scanning information.
1258 * @si: scanning information
1260 void ubi_scan_destroy_si(struct ubi_scan_info *si)
1262 struct ubi_scan_leb *seb, *seb_tmp;
1263 struct ubi_scan_volume *sv;
1266 list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) {
1267 list_del(&seb->u.list);
1270 list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {
1271 list_del(&seb->u.list);
1274 list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {
1275 list_del(&seb->u.list);
1278 list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {
1279 list_del(&seb->u.list);
1283 /* Destroy the volume RB-tree */
1284 rb = si->volumes.rb_node;
1288 else if (rb->rb_right)
1291 sv = rb_entry(rb, struct ubi_scan_volume, rb);
1295 if (rb->rb_left == &sv->rb)
1298 rb->rb_right = NULL;
1308 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1311 * paranoid_check_si - check the scanning information.
1312 * @ubi: UBI device description object
1313 * @si: scanning information
1315 * This function returns zero if the scanning information is all right, and a
1316 * negative error code if not or if an error occurred.
1318 static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
1320 int pnum, err, vols_found = 0;
1321 struct rb_node *rb1, *rb2;
1322 struct ubi_scan_volume *sv;
1323 struct ubi_scan_leb *seb, *last_seb;
1327 * At first, check that scanning information is OK.
1329 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1337 ubi_err("bad is_empty flag");
1341 if (sv->vol_id < 0 || sv->highest_lnum < 0 ||
1342 sv->leb_count < 0 || sv->vol_type < 0 || sv->used_ebs < 0 ||
1343 sv->data_pad < 0 || sv->last_data_size < 0) {
1344 ubi_err("negative values");
1348 if (sv->vol_id >= UBI_MAX_VOLUMES &&
1349 sv->vol_id < UBI_INTERNAL_VOL_START) {
1350 ubi_err("bad vol_id");
1354 if (sv->vol_id > si->highest_vol_id) {
1355 ubi_err("highest_vol_id is %d, but vol_id %d is there",
1356 si->highest_vol_id, sv->vol_id);
1360 if (sv->vol_type != UBI_DYNAMIC_VOLUME &&
1361 sv->vol_type != UBI_STATIC_VOLUME) {
1362 ubi_err("bad vol_type");
1366 if (sv->data_pad > ubi->leb_size / 2) {
1367 ubi_err("bad data_pad");
1372 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1378 if (seb->pnum < 0 || seb->ec < 0) {
1379 ubi_err("negative values");
1383 if (seb->ec < si->min_ec) {
1384 ubi_err("bad si->min_ec (%d), %d found",
1385 si->min_ec, seb->ec);
1389 if (seb->ec > si->max_ec) {
1390 ubi_err("bad si->max_ec (%d), %d found",
1391 si->max_ec, seb->ec);
1395 if (seb->pnum >= ubi->peb_count) {
1396 ubi_err("too high PEB number %d, total PEBs %d",
1397 seb->pnum, ubi->peb_count);
1401 if (sv->vol_type == UBI_STATIC_VOLUME) {
1402 if (seb->lnum >= sv->used_ebs) {
1403 ubi_err("bad lnum or used_ebs");
1407 if (sv->used_ebs != 0) {
1408 ubi_err("non-zero used_ebs");
1413 if (seb->lnum > sv->highest_lnum) {
1414 ubi_err("incorrect highest_lnum or lnum");
1419 if (sv->leb_count != leb_count) {
1420 ubi_err("bad leb_count, %d objects in the tree",
1430 if (seb->lnum != sv->highest_lnum) {
1431 ubi_err("bad highest_lnum");
1436 if (vols_found != si->vols_found) {
1437 ubi_err("bad si->vols_found %d, should be %d",
1438 si->vols_found, vols_found);
1442 /* Check that scanning information is correct */
1443 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1445 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1452 err = ubi_io_read_vid_hdr(ubi, seb->pnum, vidh, 1);
1453 if (err && err != UBI_IO_BITFLIPS) {
1454 ubi_err("VID header is not OK (%d)", err);
1460 vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
1461 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
1462 if (sv->vol_type != vol_type) {
1463 ubi_err("bad vol_type");
1467 if (seb->sqnum != be64_to_cpu(vidh->sqnum)) {
1468 ubi_err("bad sqnum %llu", seb->sqnum);
1472 if (sv->vol_id != be32_to_cpu(vidh->vol_id)) {
1473 ubi_err("bad vol_id %d", sv->vol_id);
1477 if (sv->compat != vidh->compat) {
1478 ubi_err("bad compat %d", vidh->compat);
1482 if (seb->lnum != be32_to_cpu(vidh->lnum)) {
1483 ubi_err("bad lnum %d", seb->lnum);
1487 if (sv->used_ebs != be32_to_cpu(vidh->used_ebs)) {
1488 ubi_err("bad used_ebs %d", sv->used_ebs);
1492 if (sv->data_pad != be32_to_cpu(vidh->data_pad)) {
1493 ubi_err("bad data_pad %d", sv->data_pad);
1501 if (sv->highest_lnum != be32_to_cpu(vidh->lnum)) {
1502 ubi_err("bad highest_lnum %d", sv->highest_lnum);
1506 if (sv->last_data_size != be32_to_cpu(vidh->data_size)) {
1507 ubi_err("bad last_data_size %d", sv->last_data_size);
1513 * Make sure that all the physical eraseblocks are in one of the lists
1516 buf = kzalloc(ubi->peb_count, GFP_KERNEL);
1520 for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1521 err = ubi_io_is_bad(ubi, pnum);
1529 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb)
1530 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
1533 list_for_each_entry(seb, &si->free, u.list)
1536 list_for_each_entry(seb, &si->corr, u.list)
1539 list_for_each_entry(seb, &si->erase, u.list)
1542 list_for_each_entry(seb, &si->alien, u.list)
1546 for (pnum = 0; pnum < ubi->peb_count; pnum++)
1548 ubi_err("PEB %d is not referred", pnum);
1558 ubi_err("bad scanning information about LEB %d", seb->lnum);
1559 ubi_dbg_dump_seb(seb, 0);
1560 ubi_dbg_dump_sv(sv);
1564 ubi_err("bad scanning information about volume %d", sv->vol_id);
1565 ubi_dbg_dump_sv(sv);
1569 ubi_err("bad scanning information about volume %d", sv->vol_id);
1570 ubi_dbg_dump_sv(sv);
1571 ubi_dbg_dump_vid_hdr(vidh);
1574 ubi_dbg_dump_stack();
1578 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */