/* * Copyright (c) International Business Machines Corp., 2006 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See * the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Author: Artem Bityutskiy (Битюцкий Артём) */ /* * UBI scanning sub-system. * * This sub-system is responsible for scanning the flash media, checking UBI * headers and providing complete information about the UBI flash image. * * The attaching information is represented by a &struct ubi_attach_info' * object. Information about found volumes is represented by * &struct ubi_ainf_volume objects which are kept in volume RB-tree with root * at the @volumes field. The RB-tree is indexed by the volume ID. * * Scanned logical eraseblocks are represented by &struct ubi_ainf_peb objects. * These objects are kept in per-volume RB-trees with the root at the * corresponding &struct ubi_ainf_volume object. To put it differently, we keep * an RB-tree of per-volume objects and each of these objects is the root of * RB-tree of per-eraseblock objects. * * Corrupted physical eraseblocks are put to the @corr list, free physical * eraseblocks are put to the @free list and the physical eraseblock to be * erased are put to the @erase list. * * About corruptions * ~~~~~~~~~~~~~~~~~ * * UBI protects EC and VID headers with CRC-32 checksums, so it can detect * whether the headers are corrupted or not. Sometimes UBI also protects the * data with CRC-32, e.g., when it executes the atomic LEB change operation, or * when it moves the contents of a PEB for wear-leveling purposes. * * UBI tries to distinguish between 2 types of corruptions. * * 1. Corruptions caused by power cuts. These are expected corruptions and UBI * tries to handle them gracefully, without printing too many warnings and * error messages. The idea is that we do not lose important data in these case * - we may lose only the data which was being written to the media just before * the power cut happened, and the upper layers (e.g., UBIFS) are supposed to * handle such data losses (e.g., by using the FS journal). * * When UBI detects a corruption (CRC-32 mismatch) in a PEB, and it looks like * the reason is a power cut, UBI puts this PEB to the @erase list, and all * PEBs in the @erase list are scheduled for erasure later. * * 2. Unexpected corruptions which are not caused by power cuts. During * scanning, such PEBs are put to the @corr list and UBI preserves them. * Obviously, this lessens the amount of available PEBs, and if at some point * UBI runs out of free PEBs, it switches to R/O mode. UBI also loudly informs * about such PEBs every time the MTD device is attached. * * However, it is difficult to reliably distinguish between these types of * corruptions and UBI's strategy is as follows. UBI assumes corruption type 2 * if the VID header is corrupted and the data area does not contain all 0xFFs, * and there were no bit-flips or integrity errors while reading the data area. * Otherwise UBI assumes corruption type 1. So the decision criteria are as * follows. * o If the data area contains only 0xFFs, there is no data, and it is safe * to just erase this PEB - this is corruption type 1. * o If the data area has bit-flips or data integrity errors (ECC errors on * NAND), it is probably a PEB which was being erased when power cut * happened, so this is corruption type 1. However, this is just a guess, * which might be wrong. * o Otherwise this it corruption type 2. */ #include #include #include #include #include #include "ubi.h" static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai); /* Temporary variables used during scanning */ static struct ubi_ec_hdr *ech; static struct ubi_vid_hdr *vidh; /** * add_to_list - add physical eraseblock to a list. * @ai: attaching information * @pnum: physical eraseblock number to add * @ec: erase counter of the physical eraseblock * @to_head: if not zero, add to the head of the list * @list: the list to add to * * This function adds physical eraseblock @pnum to free, erase, or alien lists. * If @to_head is not zero, PEB will be added to the head of the list, which * basically means it will be processed first later. E.g., we add corrupted * PEBs (corrupted due to power cuts) to the head of the erase list to make * sure we erase them first and get rid of corruptions ASAP. This function * returns zero in case of success and a negative error code in case of * failure. */ static int add_to_list(struct ubi_attach_info *ai, int pnum, int ec, int to_head, struct list_head *list) { struct ubi_ainf_peb *aeb; if (list == &ai->free) { dbg_bld("add to free: PEB %d, EC %d", pnum, ec); } else if (list == &ai->erase) { dbg_bld("add to erase: PEB %d, EC %d", pnum, ec); } else if (list == &ai->alien) { dbg_bld("add to alien: PEB %d, EC %d", pnum, ec); ai->alien_peb_count += 1; } else BUG(); aeb = kmem_cache_alloc(ai->scan_leb_slab, GFP_KERNEL); if (!aeb) return -ENOMEM; aeb->pnum = pnum; aeb->ec = ec; if (to_head) list_add(&aeb->u.list, list); else list_add_tail(&aeb->u.list, list); return 0; } /** * add_corrupted - add a corrupted physical eraseblock. * @ai: attaching information * @pnum: physical eraseblock number to add * @ec: erase counter of the physical eraseblock * * This function adds corrupted physical eraseblock @pnum to the 'corr' list. * The corruption was presumably not caused by a power cut. Returns zero in * case of success and a negative error code in case of failure. */ static int add_corrupted(struct ubi_attach_info *ai, int pnum, int ec) { struct ubi_ainf_peb *aeb; dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec); aeb = kmem_cache_alloc(ai->scan_leb_slab, GFP_KERNEL); if (!aeb) return -ENOMEM; ai->corr_peb_count += 1; aeb->pnum = pnum; aeb->ec = ec; list_add(&aeb->u.list, &ai->corr); return 0; } /** * validate_vid_hdr - check volume identifier header. * @vid_hdr: the volume identifier header to check * @av: information about the volume this logical eraseblock belongs to * @pnum: physical eraseblock number the VID header came from * * This function checks that data stored in @vid_hdr is consistent. Returns * non-zero if an inconsistency was found and zero if not. * * Note, UBI does sanity check of everything it reads from the flash media. * Most of the checks are done in the I/O sub-system. Here we check that the * information in the VID header is consistent to the information in other VID * headers of the same volume. */ static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr, const struct ubi_ainf_volume *av, int pnum) { int vol_type = vid_hdr->vol_type; int vol_id = be32_to_cpu(vid_hdr->vol_id); int used_ebs = be32_to_cpu(vid_hdr->used_ebs); int data_pad = be32_to_cpu(vid_hdr->data_pad); if (av->leb_count != 0) { int av_vol_type; /* * This is not the first logical eraseblock belonging to this * volume. Ensure that the data in its VID header is consistent * to the data in previous logical eraseblock headers. */ if (vol_id != av->vol_id) { ubi_err("inconsistent vol_id"); goto bad; } if (av->vol_type == UBI_STATIC_VOLUME) av_vol_type = UBI_VID_STATIC; else av_vol_type = UBI_VID_DYNAMIC; if (vol_type != av_vol_type) { ubi_err("inconsistent vol_type"); goto bad; } if (used_ebs != av->used_ebs) { ubi_err("inconsistent used_ebs"); goto bad; } if (data_pad != av->data_pad) { ubi_err("inconsistent data_pad"); goto bad; } } return 0; bad: ubi_err("inconsistent VID header at PEB %d", pnum); ubi_dump_vid_hdr(vid_hdr); ubi_dump_av(av); return -EINVAL; } /** * add_volume - add volume to the attaching information. * @ai: attaching information * @vol_id: ID of the volume to add * @pnum: physical eraseblock number * @vid_hdr: volume identifier header * * If the volume corresponding to the @vid_hdr logical eraseblock is already * present in the attaching information, this function does nothing. Otherwise * it adds corresponding volume to the attaching information. Returns a pointer * to the scanning volume object in case of success and a negative error code * in case of failure. */ static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai, int vol_id, int pnum, const struct ubi_vid_hdr *vid_hdr) { struct ubi_ainf_volume *av; struct rb_node **p = &ai->volumes.rb_node, *parent = NULL; ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id)); /* Walk the volume RB-tree to look if this volume is already present */ while (*p) { parent = *p; av = rb_entry(parent, struct ubi_ainf_volume, rb); if (vol_id == av->vol_id) return av; if (vol_id > av->vol_id) p = &(*p)->rb_left; else p = &(*p)->rb_right; } /* The volume is absent - add it */ av = kmalloc(sizeof(struct ubi_ainf_volume), GFP_KERNEL); if (!av) return ERR_PTR(-ENOMEM); av->highest_lnum = av->leb_count = 0; av->vol_id = vol_id; av->root = RB_ROOT; av->used_ebs = be32_to_cpu(vid_hdr->used_ebs); av->data_pad = be32_to_cpu(vid_hdr->data_pad); av->compat = vid_hdr->compat; av->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME; if (vol_id > ai->highest_vol_id) ai->highest_vol_id = vol_id; rb_link_node(&av->rb, parent, p); rb_insert_color(&av->rb, &ai->volumes); ai->vols_found += 1; dbg_bld("added volume %d", vol_id); return av; } /** * compare_lebs - find out which logical eraseblock is newer. * @ubi: UBI device description object * @aeb: first logical eraseblock to compare * @pnum: physical eraseblock number of the second logical eraseblock to * compare * @vid_hdr: volume identifier header of the second logical eraseblock * * This function compares 2 copies of a LEB and informs which one is newer. In * case of success this function returns a positive value, in case of failure, a * negative error code is returned. The success return codes use the following * bits: * o bit 0 is cleared: the first PEB (described by @aeb) is newer than the * second PEB (described by @pnum and @vid_hdr); * o bit 0 is set: the second PEB is newer; * o bit 1 is cleared: no bit-flips were detected in the newer LEB; * o bit 1 is set: bit-flips were detected in the newer LEB; * o bit 2 is cleared: the older LEB is not corrupted; * o bit 2 is set: the older LEB is corrupted. */ static int compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb, int pnum, const struct ubi_vid_hdr *vid_hdr) { void *buf; int len, err, second_is_newer, bitflips = 0, corrupted = 0; uint32_t data_crc, crc; struct ubi_vid_hdr *vh = NULL; unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum); if (sqnum2 == aeb->sqnum) { /* * This must be a really ancient UBI image which has been * created before sequence numbers support has been added. At * that times we used 32-bit LEB versions stored in logical * eraseblocks. That was before UBI got into mainline. We do not * support these images anymore. Well, those images still work, * but only if no unclean reboots happened. */ ubi_err("unsupported on-flash UBI format\n"); return -EINVAL; } /* Obviously the LEB with lower sequence counter is older */ second_is_newer = (sqnum2 > aeb->sqnum); /* * Now we know which copy is newer. If the copy flag of the PEB with * newer version is not set, then we just return, otherwise we have to * check data CRC. For the second PEB we already have the VID header, * for the first one - we'll need to re-read it from flash. * * Note: this may be optimized so that we wouldn't read twice. */ if (second_is_newer) { if (!vid_hdr->copy_flag) { /* It is not a copy, so it is newer */ dbg_bld("second PEB %d is newer, copy_flag is unset", pnum); return 1; } } else { if (!aeb->copy_flag) { /* It is not a copy, so it is newer */ dbg_bld("first PEB %d is newer, copy_flag is unset", pnum); return bitflips << 1; } vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL); if (!vh) return -ENOMEM; pnum = aeb->pnum; err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0); if (err) { if (err == UBI_IO_BITFLIPS) bitflips = 1; else { ubi_err("VID of PEB %d header is bad, but it " "was OK earlier, err %d", pnum, err); if (err > 0) err = -EIO; goto out_free_vidh; } } vid_hdr = vh; } /* Read the data of the copy and check the CRC */ len = be32_to_cpu(vid_hdr->data_size); buf = vmalloc(len); if (!buf) { err = -ENOMEM; goto out_free_vidh; } err = ubi_io_read_data(ubi, buf, pnum, 0, len); if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err)) goto out_free_buf; data_crc = be32_to_cpu(vid_hdr->data_crc); crc = crc32(UBI_CRC32_INIT, buf, len); if (crc != data_crc) { dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x", pnum, crc, data_crc); corrupted = 1; bitflips = 0; second_is_newer = !second_is_newer; } else { dbg_bld("PEB %d CRC is OK", pnum); bitflips = !!err; } vfree(buf); ubi_free_vid_hdr(ubi, vh); if (second_is_newer) dbg_bld("second PEB %d is newer, copy_flag is set", pnum); else dbg_bld("first PEB %d is newer, copy_flag is set", pnum); return second_is_newer | (bitflips << 1) | (corrupted << 2); out_free_buf: vfree(buf); out_free_vidh: ubi_free_vid_hdr(ubi, vh); return err; } /** * ubi_add_to_av - add physical eraseblock to the attaching information. * @ubi: UBI device description object * @ai: attaching information * @pnum: the physical eraseblock number * @ec: erase counter * @vid_hdr: the volume identifier header * @bitflips: if bit-flips were detected when this physical eraseblock was read * * This function adds information about a used physical eraseblock to the * 'used' tree of the corresponding volume. The function is rather complex * because it has to handle cases when this is not the first physical * eraseblock belonging to the same logical eraseblock, and the newer one has * to be picked, while the older one has to be dropped. This function returns * zero in case of success and a negative error code in case of failure. */ int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum, int ec, const struct ubi_vid_hdr *vid_hdr, int bitflips) { int err, vol_id, lnum; unsigned long long sqnum; struct ubi_ainf_volume *av; struct ubi_ainf_peb *aeb; struct rb_node **p, *parent = NULL; vol_id = be32_to_cpu(vid_hdr->vol_id); lnum = be32_to_cpu(vid_hdr->lnum); sqnum = be64_to_cpu(vid_hdr->sqnum); dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d", pnum, vol_id, lnum, ec, sqnum, bitflips); av = add_volume(ai, vol_id, pnum, vid_hdr); if (IS_ERR(av)) return PTR_ERR(av); if (ai->max_sqnum < sqnum) ai->max_sqnum = sqnum; /* * Walk the RB-tree of logical eraseblocks of volume @vol_id to look * if this is the first instance of this logical eraseblock or not. */ p = &av->root.rb_node; while (*p) { int cmp_res; parent = *p; aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb); if (lnum != aeb->lnum) { if (lnum < aeb->lnum) p = &(*p)->rb_left; else p = &(*p)->rb_right; continue; } /* * There is already a physical eraseblock describing the same * logical eraseblock present. */ dbg_bld("this LEB already exists: PEB %d, sqnum %llu, EC %d", aeb->pnum, aeb->sqnum, aeb->ec); /* * Make sure that the logical eraseblocks have different * sequence numbers. Otherwise the image is bad. * * However, if the sequence number is zero, we assume it must * be an ancient UBI image from the era when UBI did not have * sequence numbers. We still can attach these images, unless * there is a need to distinguish between old and new * eraseblocks, in which case we'll refuse the image in * 'compare_lebs()'. In other words, we attach old clean * images, but refuse attaching old images with duplicated * logical eraseblocks because there was an unclean reboot. */ if (aeb->sqnum == sqnum && sqnum != 0) { ubi_err("two LEBs with same sequence number %llu", sqnum); ubi_dump_aeb(aeb, 0); ubi_dump_vid_hdr(vid_hdr); return -EINVAL; } /* * Now we have to drop the older one and preserve the newer * one. */ cmp_res = compare_lebs(ubi, aeb, pnum, vid_hdr); if (cmp_res < 0) return cmp_res; if (cmp_res & 1) { /* * This logical eraseblock is newer than the one * found earlier. */ err = validate_vid_hdr(vid_hdr, av, pnum); if (err) return err; err = add_to_list(ai, aeb->pnum, aeb->ec, cmp_res & 4, &ai->erase); if (err) return err; aeb->ec = ec; aeb->pnum = pnum; aeb->scrub = ((cmp_res & 2) || bitflips); aeb->copy_flag = vid_hdr->copy_flag; aeb->sqnum = sqnum; if (av->highest_lnum == lnum) av->last_data_size = be32_to_cpu(vid_hdr->data_size); return 0; } else { /* * This logical eraseblock is older than the one found * previously. */ return add_to_list(ai, pnum, ec, cmp_res & 4, &ai->erase); } } /* * We've met this logical eraseblock for the first time, add it to the * attaching information. */ err = validate_vid_hdr(vid_hdr, av, pnum); if (err) return err; aeb = kmem_cache_alloc(ai->scan_leb_slab, GFP_KERNEL); if (!aeb) return -ENOMEM; aeb->ec = ec; aeb->pnum = pnum; aeb->lnum = lnum; aeb->scrub = bitflips; aeb->copy_flag = vid_hdr->copy_flag; aeb->sqnum = sqnum; if (av->highest_lnum <= lnum) { av->highest_lnum = lnum; av->last_data_size = be32_to_cpu(vid_hdr->data_size); } av->leb_count += 1; rb_link_node(&aeb->u.rb, parent, p); rb_insert_color(&aeb->u.rb, &av->root); return 0; } /** * ubi_find_av - find volume in the attaching information. * @ai: attaching information * @vol_id: the requested volume ID * * This function returns a pointer to the volume description or %NULL if there * are no data about this volume in the attaching information. */ struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai, int vol_id) { struct ubi_ainf_volume *av; struct rb_node *p = ai->volumes.rb_node; while (p) { av = rb_entry(p, struct ubi_ainf_volume, rb); if (vol_id == av->vol_id) return av; if (vol_id > av->vol_id) p = p->rb_left; else p = p->rb_right; } return NULL; } /** * ubi_remove_av - delete attaching information about a volume. * @ai: attaching information * @av: the volume attaching information to delete */ void ubi_remove_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av) { struct rb_node *rb; struct ubi_ainf_peb *aeb; dbg_bld("remove attaching information about volume %d", av->vol_id); while ((rb = rb_first(&av->root))) { aeb = rb_entry(rb, struct ubi_ainf_peb, u.rb); rb_erase(&aeb->u.rb, &av->root); list_add_tail(&aeb->u.list, &ai->erase); } rb_erase(&av->rb, &ai->volumes); kfree(av); ai->vols_found -= 1; } /** * early_erase_peb - erase a physical eraseblock. * @ubi: UBI device description object * @ai: attaching information * @pnum: physical eraseblock number to erase; * @ec: erase counter value to write (%UBI_SCAN_UNKNOWN_EC if it is unknown) * * This function erases physical eraseblock 'pnum', and writes the erase * counter header to it. This function should only be used on UBI device * initialization stages, when the EBA sub-system had not been yet initialized. * This function returns zero in case of success and a negative error code in * case of failure. */ static int early_erase_peb(struct ubi_device *ubi, const struct ubi_attach_info *ai, int pnum, int ec) { int err; struct ubi_ec_hdr *ec_hdr; if ((long long)ec >= UBI_MAX_ERASECOUNTER) { /* * Erase counter overflow. Upgrade UBI and use 64-bit * erase counters internally. */ ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec); return -EINVAL; } ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); if (!ec_hdr) return -ENOMEM; ec_hdr->ec = cpu_to_be64(ec); err = ubi_io_sync_erase(ubi, pnum, 0); if (err < 0) goto out_free; err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr); out_free: kfree(ec_hdr); return err; } /** * ubi_scan_get_free_peb - get a free physical eraseblock. * @ubi: UBI device description object * @ai: attaching information * * This function returns a free physical eraseblock. It is supposed to be * called on the UBI initialization stages when the wear-leveling sub-system is * not initialized yet. This function picks a physical eraseblocks from one of * the lists, writes the EC header if it is needed, and removes it from the * list. * * This function returns scanning physical eraseblock information in case of * success and an error code in case of failure. */ struct ubi_ainf_peb *ubi_scan_get_free_peb(struct ubi_device *ubi, struct ubi_attach_info *ai) { int err = 0; struct ubi_ainf_peb *aeb, *tmp_aeb; if (!list_empty(&ai->free)) { aeb = list_entry(ai->free.next, struct ubi_ainf_peb, u.list); list_del(&aeb->u.list); dbg_bld("return free PEB %d, EC %d", aeb->pnum, aeb->ec); return aeb; } /* * We try to erase the first physical eraseblock from the erase list * and pick it if we succeed, or try to erase the next one if not. And * so forth. We don't want to take care about bad eraseblocks here - * they'll be handled later. */ list_for_each_entry_safe(aeb, tmp_aeb, &ai->erase, u.list) { if (aeb->ec == UBI_SCAN_UNKNOWN_EC) aeb->ec = ai->mean_ec; err = early_erase_peb(ubi, ai, aeb->pnum, aeb->ec+1); if (err) continue; aeb->ec += 1; list_del(&aeb->u.list); dbg_bld("return PEB %d, EC %d", aeb->pnum, aeb->ec); return aeb; } ubi_err("no free eraseblocks"); return ERR_PTR(-ENOSPC); } /** * check_corruption - check the data area of PEB. * @ubi: UBI device description object * @vid_hrd: the (corrupted) VID header of this PEB * @pnum: the physical eraseblock number to check * * This is a helper function which is used to distinguish between VID header * corruptions caused by power cuts and other reasons. If the PEB contains only * 0xFF bytes in the data area, the VID header is most probably corrupted * because of a power cut (%0 is returned in this case). Otherwise, it was * probably corrupted for some other reasons (%1 is returned in this case). A * negative error code is returned if a read error occurred. * * If the corruption reason was a power cut, UBI can safely erase this PEB. * Otherwise, it should preserve it to avoid possibly destroying important * information. */ static int check_corruption(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr, int pnum) { int err; mutex_lock(&ubi->buf_mutex); memset(ubi->peb_buf, 0x00, ubi->leb_size); err = ubi_io_read(ubi, ubi->peb_buf, pnum, ubi->leb_start, ubi->leb_size); if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) { /* * Bit-flips or integrity errors while reading the data area. * It is difficult to say for sure what type of corruption is * this, but presumably a power cut happened while this PEB was * erased, so it became unstable and corrupted, and should be * erased. */ err = 0; goto out_unlock; } if (err) goto out_unlock; if (ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->leb_size)) goto out_unlock; ubi_err("PEB %d contains corrupted VID header, and the data does not " "contain all 0xFF, this may be a non-UBI PEB or a severe VID " "header corruption which requires manual inspection", pnum); ubi_dump_vid_hdr(vid_hdr); dbg_msg("hexdump of PEB %d offset %d, length %d", pnum, ubi->leb_start, ubi->leb_size); ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, ubi->peb_buf, ubi->leb_size, 1); err = 1; out_unlock: mutex_unlock(&ubi->buf_mutex); return err; } /** * process_eb - read, check UBI headers, and add them to attaching information. * @ubi: UBI device description object * @ai: attaching information * @pnum: the physical eraseblock number * * This function returns a zero if the physical eraseblock was successfully * handled and a negative error code in case of failure. */ static int process_eb(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum) { long long uninitialized_var(ec); int err, bitflips = 0, vol_id, ec_err = 0; dbg_bld("scan PEB %d", pnum); /* Skip bad physical eraseblocks */ err = ubi_io_is_bad(ubi, pnum); if (err < 0) return err; else if (err) { /* * FIXME: this is actually duty of the I/O sub-system to * initialize this, but MTD does not provide enough * information. */ ai->bad_peb_count += 1; return 0; } err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0); if (err < 0) return err; switch (err) { case 0: break; case UBI_IO_BITFLIPS: bitflips = 1; break; case UBI_IO_FF: ai->empty_peb_count += 1; return add_to_list(ai, pnum, UBI_SCAN_UNKNOWN_EC, 0, &ai->erase); case UBI_IO_FF_BITFLIPS: ai->empty_peb_count += 1; return add_to_list(ai, pnum, UBI_SCAN_UNKNOWN_EC, 1, &ai->erase); case UBI_IO_BAD_HDR_EBADMSG: case UBI_IO_BAD_HDR: /* * We have to also look at the VID header, possibly it is not * corrupted. Set %bitflips flag in order to make this PEB be * moved and EC be re-created. */ ec_err = err; ec = UBI_SCAN_UNKNOWN_EC; bitflips = 1; break; default: ubi_err("'ubi_io_read_ec_hdr()' returned unknown code %d", err); return -EINVAL; } if (!ec_err) { int image_seq; /* Make sure UBI version is OK */ if (ech->version != UBI_VERSION) { ubi_err("this UBI version is %d, image version is %d", UBI_VERSION, (int)ech->version); return -EINVAL; } ec = be64_to_cpu(ech->ec); if (ec > UBI_MAX_ERASECOUNTER) { /* * Erase counter overflow. The EC headers have 64 bits * reserved, but we anyway make use of only 31 bit * values, as this seems to be enough for any existing * flash. Upgrade UBI and use 64-bit erase counters * internally. */ ubi_err("erase counter overflow, max is %d", UBI_MAX_ERASECOUNTER); ubi_dump_ec_hdr(ech); return -EINVAL; } /* * Make sure that all PEBs have the same image sequence number. * This allows us to detect situations when users flash UBI * images incorrectly, so that the flash has the new UBI image * and leftovers from the old one. This feature was added * relatively recently, and the sequence number was always * zero, because old UBI implementations always set it to zero. * For this reasons, we do not panic if some PEBs have zero * sequence number, while other PEBs have non-zero sequence * number. */ image_seq = be32_to_cpu(ech->image_seq); if (!ubi->image_seq && image_seq) ubi->image_seq = image_seq; if (ubi->image_seq && image_seq && ubi->image_seq != image_seq) { ubi_err("bad image sequence number %d in PEB %d, " "expected %d", image_seq, pnum, ubi->image_seq); ubi_dump_ec_hdr(ech); return -EINVAL; } } /* OK, we've done with the EC header, let's look at the VID header */ err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0); if (err < 0) return err; switch (err) { case 0: break; case UBI_IO_BITFLIPS: bitflips = 1; break; case UBI_IO_BAD_HDR_EBADMSG: if (ec_err == UBI_IO_BAD_HDR_EBADMSG) /* * Both EC and VID headers are corrupted and were read * with data integrity error, probably this is a bad * PEB, bit it is not marked as bad yet. This may also * be a result of power cut during erasure. */ ai->maybe_bad_peb_count += 1; case UBI_IO_BAD_HDR: if (ec_err) /* * Both headers are corrupted. There is a possibility * that this a valid UBI PEB which has corresponding * LEB, but the headers are corrupted. However, it is * impossible to distinguish it from a PEB which just * contains garbage because of a power cut during erase * operation. So we just schedule this PEB for erasure. * * Besides, in case of NOR flash, we deliberately * corrupt both headers because NOR flash erasure is * slow and can start from the end. */ err = 0; else /* * The EC was OK, but the VID header is corrupted. We * have to check what is in the data area. */ err = check_corruption(ubi, vidh, pnum); if (err < 0) return err; else if (!err) /* This corruption is caused by a power cut */ err = add_to_list(ai, pnum, ec, 1, &ai->erase); else /* This is an unexpected corruption */ err = add_corrupted(ai, pnum, ec); if (err) return err; goto adjust_mean_ec; case UBI_IO_FF_BITFLIPS: err = add_to_list(ai, pnum, ec, 1, &ai->erase); if (err) return err; goto adjust_mean_ec; case UBI_IO_FF: if (ec_err) err = add_to_list(ai, pnum, ec, 1, &ai->erase); else err = add_to_list(ai, pnum, ec, 0, &ai->free); if (err) return err; goto adjust_mean_ec; default: ubi_err("'ubi_io_read_vid_hdr()' returned unknown code %d", err); return -EINVAL; } vol_id = be32_to_cpu(vidh->vol_id); if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) { int lnum = be32_to_cpu(vidh->lnum); /* Unsupported internal volume */ switch (vidh->compat) { case UBI_COMPAT_DELETE: ubi_msg("\"delete\" compatible internal volume %d:%d" " found, will remove it", vol_id, lnum); err = add_to_list(ai, pnum, ec, 1, &ai->erase); if (err) return err; return 0; case UBI_COMPAT_RO: ubi_msg("read-only compatible internal volume %d:%d" " found, switch to read-only mode", vol_id, lnum); ubi->ro_mode = 1; break; case UBI_COMPAT_PRESERVE: ubi_msg("\"preserve\" compatible internal volume %d:%d" " found", vol_id, lnum); err = add_to_list(ai, pnum, ec, 0, &ai->alien); if (err) return err; return 0; case UBI_COMPAT_REJECT: ubi_err("incompatible internal volume %d:%d found", vol_id, lnum); return -EINVAL; } } if (ec_err) ubi_warn("valid VID header but corrupted EC header at PEB %d", pnum); err = ubi_add_to_av(ubi, ai, pnum, ec, vidh, bitflips); if (err) return err; adjust_mean_ec: if (!ec_err) { ai->ec_sum += ec; ai->ec_count += 1; if (ec > ai->max_ec) ai->max_ec = ec; if (ec < ai->min_ec) ai->min_ec = ec; } return 0; } /** * check_what_we_have - check what PEB were found by scanning. * @ubi: UBI device description object * @ai: attaching information * * This is a helper function which takes a look what PEBs were found by * scanning, and decides whether the flash is empty and should be formatted and * whether there are too many corrupted PEBs and we should not attach this * MTD device. Returns zero if we should proceed with attaching the MTD device, * and %-EINVAL if we should not. */ static int check_what_we_have(struct ubi_device *ubi, struct ubi_attach_info *ai) { struct ubi_ainf_peb *aeb; int max_corr, peb_count; peb_count = ubi->peb_count - ai->bad_peb_count - ai->alien_peb_count; max_corr = peb_count / 20 ?: 8; /* * Few corrupted PEBs is not a problem and may be just a result of * unclean reboots. However, many of them may indicate some problems * with the flash HW or driver. */ if (ai->corr_peb_count) { ubi_err("%d PEBs are corrupted and preserved", ai->corr_peb_count); printk(KERN_ERR "Corrupted PEBs are:"); list_for_each_entry(aeb, &ai->corr, u.list) printk(KERN_CONT " %d", aeb->pnum); printk(KERN_CONT "\n"); /* * If too many PEBs are corrupted, we refuse attaching, * otherwise, only print a warning. */ if (ai->corr_peb_count >= max_corr) { ubi_err("too many corrupted PEBs, refusing"); return -EINVAL; } } if (ai->empty_peb_count + ai->maybe_bad_peb_count == peb_count) { /* * All PEBs are empty, or almost all - a couple PEBs look like * they may be bad PEBs which were not marked as bad yet. * * This piece of code basically tries to distinguish between * the following situations: * * 1. Flash is empty, but there are few bad PEBs, which are not * marked as bad so far, and which were read with error. We * want to go ahead and format this flash. While formatting, * the faulty PEBs will probably be marked as bad. * * 2. Flash contains non-UBI data and we do not want to format * it and destroy possibly important information. */ if (ai->maybe_bad_peb_count <= 2) { ai->is_empty = 1; ubi_msg("empty MTD device detected"); get_random_bytes(&ubi->image_seq, sizeof(ubi->image_seq)); } else { ubi_err("MTD device is not UBI-formatted and possibly " "contains non-UBI data - refusing it"); return -EINVAL; } } return 0; } /** * ubi_scan - scan an MTD device. * @ubi: UBI device description object * * This function does full scanning of an MTD device and returns complete * information about it. In case of failure, an error code is returned. */ struct ubi_attach_info *ubi_scan(struct ubi_device *ubi) { int err, pnum; struct rb_node *rb1, *rb2; struct ubi_ainf_volume *av; struct ubi_ainf_peb *aeb; struct ubi_attach_info *ai; ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL); if (!ai) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&ai->corr); INIT_LIST_HEAD(&ai->free); INIT_LIST_HEAD(&ai->erase); INIT_LIST_HEAD(&ai->alien); ai->volumes = RB_ROOT; err = -ENOMEM; ai->scan_leb_slab = kmem_cache_create("ubi_scan_leb_slab", sizeof(struct ubi_ainf_peb), 0, 0, NULL); if (!ai->scan_leb_slab) goto out_ai; ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); if (!ech) goto out_ai; vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL); if (!vidh) goto out_ech; for (pnum = 0; pnum < ubi->peb_count; pnum++) { cond_resched(); dbg_gen("process PEB %d", pnum); err = process_eb(ubi, ai, pnum); if (err < 0) goto out_vidh; } dbg_msg("scanning is finished"); /* Calculate mean erase counter */ if (ai->ec_count) ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count); err = check_what_we_have(ubi, ai); if (err) goto out_vidh; /* * In case of unknown erase counter we use the mean erase counter * value. */ ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) { ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) if (aeb->ec == UBI_SCAN_UNKNOWN_EC) aeb->ec = ai->mean_ec; } list_for_each_entry(aeb, &ai->free, u.list) { if (aeb->ec == UBI_SCAN_UNKNOWN_EC) aeb->ec = ai->mean_ec; } list_for_each_entry(aeb, &ai->corr, u.list) if (aeb->ec == UBI_SCAN_UNKNOWN_EC) aeb->ec = ai->mean_ec; list_for_each_entry(aeb, &ai->erase, u.list) if (aeb->ec == UBI_SCAN_UNKNOWN_EC) aeb->ec = ai->mean_ec; err = self_check_ai(ubi, ai); if (err) goto out_vidh; ubi_free_vid_hdr(ubi, vidh); kfree(ech); return ai; out_vidh: ubi_free_vid_hdr(ubi, vidh); out_ech: kfree(ech); out_ai: ubi_scan_destroy_ai(ai); return ERR_PTR(err); } /** * destroy_av - free the scanning volume information * @av: scanning volume information * @ai: attaching information * * This function destroys the volume RB-tree (@av->root) and the scanning * volume information. */ static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av) { struct ubi_ainf_peb *aeb; struct rb_node *this = av->root.rb_node; while (this) { if (this->rb_left) this = this->rb_left; else if (this->rb_right) this = this->rb_right; else { aeb = rb_entry(this, struct ubi_ainf_peb, u.rb); this = rb_parent(this); if (this) { if (this->rb_left == &aeb->u.rb) this->rb_left = NULL; else this->rb_right = NULL; } kmem_cache_free(ai->scan_leb_slab, aeb); } } kfree(av); } /** * ubi_scan_destroy_ai - destroy attaching information. * @ai: attaching information */ void ubi_scan_destroy_ai(struct ubi_attach_info *ai) { struct ubi_ainf_peb *aeb, *aeb_tmp; struct ubi_ainf_volume *av; struct rb_node *rb; list_for_each_entry_safe(aeb, aeb_tmp, &ai->alien, u.list) { list_del(&aeb->u.list); kmem_cache_free(ai->scan_leb_slab, aeb); } list_for_each_entry_safe(aeb, aeb_tmp, &ai->erase, u.list) { list_del(&aeb->u.list); kmem_cache_free(ai->scan_leb_slab, aeb); } list_for_each_entry_safe(aeb, aeb_tmp, &ai->corr, u.list) { list_del(&aeb->u.list); kmem_cache_free(ai->scan_leb_slab, aeb); } list_for_each_entry_safe(aeb, aeb_tmp, &ai->free, u.list) { list_del(&aeb->u.list); kmem_cache_free(ai->scan_leb_slab, aeb); } /* Destroy the volume RB-tree */ rb = ai->volumes.rb_node; while (rb) { if (rb->rb_left) rb = rb->rb_left; else if (rb->rb_right) rb = rb->rb_right; else { av = rb_entry(rb, struct ubi_ainf_volume, rb); rb = rb_parent(rb); if (rb) { if (rb->rb_left == &av->rb) rb->rb_left = NULL; else rb->rb_right = NULL; } destroy_av(ai, av); } } if (ai->scan_leb_slab) kmem_cache_destroy(ai->scan_leb_slab); kfree(ai); } /** * self_check_ai - check the attaching information. * @ubi: UBI device description object * @ai: attaching information * * This function returns zero if the attaching information is all right, and a * negative error code if not or if an error occurred. */ static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai) { int pnum, err, vols_found = 0; struct rb_node *rb1, *rb2; struct ubi_ainf_volume *av; struct ubi_ainf_peb *aeb, *last_aeb; uint8_t *buf; if (!ubi->dbg->chk_gen) return 0; /* * At first, check that attaching information is OK. */ ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) { int leb_count = 0; cond_resched(); vols_found += 1; if (ai->is_empty) { ubi_err("bad is_empty flag"); goto bad_av; } if (av->vol_id < 0 || av->highest_lnum < 0 || av->leb_count < 0 || av->vol_type < 0 || av->used_ebs < 0 || av->data_pad < 0 || av->last_data_size < 0) { ubi_err("negative values"); goto bad_av; } if (av->vol_id >= UBI_MAX_VOLUMES && av->vol_id < UBI_INTERNAL_VOL_START) { ubi_err("bad vol_id"); goto bad_av; } if (av->vol_id > ai->highest_vol_id) { ubi_err("highest_vol_id is %d, but vol_id %d is there", ai->highest_vol_id, av->vol_id); goto out; } if (av->vol_type != UBI_DYNAMIC_VOLUME && av->vol_type != UBI_STATIC_VOLUME) { ubi_err("bad vol_type"); goto bad_av; } if (av->data_pad > ubi->leb_size / 2) { ubi_err("bad data_pad"); goto bad_av; } last_aeb = NULL; ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) { cond_resched(); last_aeb = aeb; leb_count += 1; if (aeb->pnum < 0 || aeb->ec < 0) { ubi_err("negative values"); goto bad_aeb; } if (aeb->ec < ai->min_ec) { ubi_err("bad ai->min_ec (%d), %d found", ai->min_ec, aeb->ec); goto bad_aeb; } if (aeb->ec > ai->max_ec) { ubi_err("bad ai->max_ec (%d), %d found", ai->max_ec, aeb->ec); goto bad_aeb; } if (aeb->pnum >= ubi->peb_count) { ubi_err("too high PEB number %d, total PEBs %d", aeb->pnum, ubi->peb_count); goto bad_aeb; } if (av->vol_type == UBI_STATIC_VOLUME) { if (aeb->lnum >= av->used_ebs) { ubi_err("bad lnum or used_ebs"); goto bad_aeb; } } else { if (av->used_ebs != 0) { ubi_err("non-zero used_ebs"); goto bad_aeb; } } if (aeb->lnum > av->highest_lnum) { ubi_err("incorrect highest_lnum or lnum"); goto bad_aeb; } } if (av->leb_count != leb_count) { ubi_err("bad leb_count, %d objects in the tree", leb_count); goto bad_av; } if (!last_aeb) continue; aeb = last_aeb; if (aeb->lnum != av->highest_lnum) { ubi_err("bad highest_lnum"); goto bad_aeb; } } if (vols_found != ai->vols_found) { ubi_err("bad ai->vols_found %d, should be %d", ai->vols_found, vols_found); goto out; } /* Check that attaching information is correct */ ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) { last_aeb = NULL; ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) { int vol_type; cond_resched(); last_aeb = aeb; err = ubi_io_read_vid_hdr(ubi, aeb->pnum, vidh, 1); if (err && err != UBI_IO_BITFLIPS) { ubi_err("VID header is not OK (%d)", err); if (err > 0) err = -EIO; return err; } vol_type = vidh->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME; if (av->vol_type != vol_type) { ubi_err("bad vol_type"); goto bad_vid_hdr; } if (aeb->sqnum != be64_to_cpu(vidh->sqnum)) { ubi_err("bad sqnum %llu", aeb->sqnum); goto bad_vid_hdr; } if (av->vol_id != be32_to_cpu(vidh->vol_id)) { ubi_err("bad vol_id %d", av->vol_id); goto bad_vid_hdr; } if (av->compat != vidh->compat) { ubi_err("bad compat %d", vidh->compat); goto bad_vid_hdr; } if (aeb->lnum != be32_to_cpu(vidh->lnum)) { ubi_err("bad lnum %d", aeb->lnum); goto bad_vid_hdr; } if (av->used_ebs != be32_to_cpu(vidh->used_ebs)) { ubi_err("bad used_ebs %d", av->used_ebs); goto bad_vid_hdr; } if (av->data_pad != be32_to_cpu(vidh->data_pad)) { ubi_err("bad data_pad %d", av->data_pad); goto bad_vid_hdr; } } if (!last_aeb) continue; if (av->highest_lnum != be32_to_cpu(vidh->lnum)) { ubi_err("bad highest_lnum %d", av->highest_lnum); goto bad_vid_hdr; } if (av->last_data_size != be32_to_cpu(vidh->data_size)) { ubi_err("bad last_data_size %d", av->last_data_size); goto bad_vid_hdr; } } /* * Make sure that all the physical eraseblocks are in one of the lists * or trees. */ buf = kzalloc(ubi->peb_count, GFP_KERNEL); if (!buf) return -ENOMEM; for (pnum = 0; pnum < ubi->peb_count; pnum++) { err = ubi_io_is_bad(ubi, pnum); if (err < 0) { kfree(buf); return err; } else if (err) buf[pnum] = 1; } ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) buf[aeb->pnum] = 1; list_for_each_entry(aeb, &ai->free, u.list) buf[aeb->pnum] = 1; list_for_each_entry(aeb, &ai->corr, u.list) buf[aeb->pnum] = 1; list_for_each_entry(aeb, &ai->erase, u.list) buf[aeb->pnum] = 1; list_for_each_entry(aeb, &ai->alien, u.list) buf[aeb->pnum] = 1; err = 0; for (pnum = 0; pnum < ubi->peb_count; pnum++) if (!buf[pnum]) { ubi_err("PEB %d is not referred", pnum); err = 1; } kfree(buf); if (err) goto out; return 0; bad_aeb: ubi_err("bad attaching information about LEB %d", aeb->lnum); ubi_dump_aeb(aeb, 0); ubi_dump_av(av); goto out; bad_av: ubi_err("bad attaching information about volume %d", av->vol_id); ubi_dump_av(av); goto out; bad_vid_hdr: ubi_err("bad attaching information about volume %d", av->vol_id); ubi_dump_av(av); ubi_dump_vid_hdr(vidh); out: dump_stack(); return -EINVAL; }