/* * 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 scanning information is represented by a &struct ubi_scan_info' object. * Information about found volumes is represented by &struct ubi_scan_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_scan_leb objects. * These objects are kept in per-volume RB-trees with the root at the * corresponding &struct ubi_scan_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" #ifdef CONFIG_MTD_UBI_DEBUG static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si); #else #define paranoid_check_si(ubi, si) 0 #endif /* 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. * @si: scanning 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_scan_info *si, int pnum, int ec, int to_head, struct list_head *list) { struct ubi_scan_leb *seb; if (list == &si->free) { dbg_bld("add to free: PEB %d, EC %d", pnum, ec); } else if (list == &si->erase) { dbg_bld("add to erase: PEB %d, EC %d", pnum, ec); } else if (list == &si->alien) { dbg_bld("add to alien: PEB %d, EC %d", pnum, ec); si->alien_peb_count += 1; } else BUG(); seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL); if (!seb) return -ENOMEM; seb->pnum = pnum; seb->ec = ec; if (to_head) list_add(&seb->u.list, list); else list_add_tail(&seb->u.list, list); return 0; } /** * add_corrupted - add a corrupted physical eraseblock. * @si: scanning 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_scan_info *si, int pnum, int ec) { struct ubi_scan_leb *seb; dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec); seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL); if (!seb) return -ENOMEM; si->corr_peb_count += 1; seb->pnum = pnum; seb->ec = ec; list_add(&seb->u.list, &si->corr); return 0; } /** * validate_vid_hdr - check volume identifier header. * @vid_hdr: the volume identifier header to check * @sv: 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_scan_volume *sv, 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 (sv->leb_count != 0) { int sv_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 != sv->vol_id) { dbg_err("inconsistent vol_id"); goto bad; } if (sv->vol_type == UBI_STATIC_VOLUME) sv_vol_type = UBI_VID_STATIC; else sv_vol_type = UBI_VID_DYNAMIC; if (vol_type != sv_vol_type) { dbg_err("inconsistent vol_type"); goto bad; } if (used_ebs != sv->used_ebs) { dbg_err("inconsistent used_ebs"); goto bad; } if (data_pad != sv->data_pad) { dbg_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_sv(sv); return -EINVAL; } /** * add_volume - add volume to the scanning information. * @si: scanning 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 scanning information, this function does nothing. Otherwise * it adds corresponding volume to the scanning 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_scan_volume *add_volume(struct ubi_scan_info *si, int vol_id, int pnum, const struct ubi_vid_hdr *vid_hdr) { struct ubi_scan_volume *sv; struct rb_node **p = &si->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; sv = rb_entry(parent, struct ubi_scan_volume, rb); if (vol_id == sv->vol_id) return sv; if (vol_id > sv->vol_id) p = &(*p)->rb_left; else p = &(*p)->rb_right; } /* The volume is absent - add it */ sv = kmalloc(sizeof(struct ubi_scan_volume), GFP_KERNEL); if (!sv) return ERR_PTR(-ENOMEM); sv->highest_lnum = sv->leb_count = 0; sv->vol_id = vol_id; sv->root = RB_ROOT; sv->used_ebs = be32_to_cpu(vid_hdr->used_ebs); sv->data_pad = be32_to_cpu(vid_hdr->data_pad); sv->compat = vid_hdr->compat; sv->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME; if (vol_id > si->highest_vol_id) si->highest_vol_id = vol_id; rb_link_node(&sv->rb, parent, p); rb_insert_color(&sv->rb, &si->volumes); si->vols_found += 1; dbg_bld("added volume %d", vol_id); return sv; } /** * compare_lebs - find out which logical eraseblock is newer. * @ubi: UBI device description object * @seb: 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 @seb) 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_scan_leb *seb, 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 == seb->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 > seb->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 (!seb->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 = seb->pnum; err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0); if (err) { if (err == UBI_IO_BITFLIPS) bitflips = 1; else { dbg_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_scan_add_used - add physical eraseblock to the scanning information. * @ubi: UBI device description object * @si: scanning 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_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si, int pnum, int ec, const struct ubi_vid_hdr *vid_hdr, int bitflips) { int err, vol_id, lnum; unsigned long long sqnum; struct ubi_scan_volume *sv; struct ubi_scan_leb *seb; 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); sv = add_volume(si, vol_id, pnum, vid_hdr); if (IS_ERR(sv)) return PTR_ERR(sv); if (si->max_sqnum < sqnum) si->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 = &sv->root.rb_node; while (*p) { int cmp_res; parent = *p; seb = rb_entry(parent, struct ubi_scan_leb, u.rb); if (lnum != seb->lnum) { if (lnum < seb->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", seb->pnum, seb->sqnum, seb->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 (seb->sqnum == sqnum && sqnum != 0) { ubi_err("two LEBs with same sequence number %llu", sqnum); ubi_dump_seb(seb, 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, seb, 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, sv, pnum); if (err) return err; err = add_to_list(si, seb->pnum, seb->ec, cmp_res & 4, &si->erase); if (err) return err; seb->ec = ec; seb->pnum = pnum; seb->scrub = ((cmp_res & 2) || bitflips); seb->copy_flag = vid_hdr->copy_flag; seb->sqnum = sqnum; if (sv->highest_lnum == lnum) sv->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(si, pnum, ec, cmp_res & 4, &si->erase); } } /* * We've met this logical eraseblock for the first time, add it to the * scanning information. */ err = validate_vid_hdr(vid_hdr, sv, pnum); if (err) return err; seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL); if (!seb) return -ENOMEM; seb->ec = ec; seb->pnum = pnum; seb->lnum = lnum; seb->scrub = bitflips; seb->copy_flag = vid_hdr->copy_flag; seb->sqnum = sqnum; if (sv->highest_lnum <= lnum) { sv->highest_lnum = lnum; sv->last_data_size = be32_to_cpu(vid_hdr->data_size); } sv->leb_count += 1; rb_link_node(&seb->u.rb, parent, p); rb_insert_color(&seb->u.rb, &sv->root); return 0; } /** * ubi_scan_find_sv - find volume in the scanning information. * @si: scanning 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 scanning information. */ struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si, int vol_id) { struct ubi_scan_volume *sv; struct rb_node *p = si->volumes.rb_node; while (p) { sv = rb_entry(p, struct ubi_scan_volume, rb); if (vol_id == sv->vol_id) return sv; if (vol_id > sv->vol_id) p = p->rb_left; else p = p->rb_right; } return NULL; } /** * ubi_scan_find_seb - find LEB in the volume scanning information. * @sv: a pointer to the volume scanning information * @lnum: the requested logical eraseblock * * This function returns a pointer to the scanning logical eraseblock or %NULL * if there are no data about it in the scanning volume information. */ struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv, int lnum) { struct ubi_scan_leb *seb; struct rb_node *p = sv->root.rb_node; while (p) { seb = rb_entry(p, struct ubi_scan_leb, u.rb); if (lnum == seb->lnum) return seb; if (lnum > seb->lnum) p = p->rb_left; else p = p->rb_right; } return NULL; } /** * ubi_scan_rm_volume - delete scanning information about a volume. * @si: scanning information * @sv: the volume scanning information to delete */ void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv) { struct rb_node *rb; struct ubi_scan_leb *seb; dbg_bld("remove scanning information about volume %d", sv->vol_id); while ((rb = rb_first(&sv->root))) { seb = rb_entry(rb, struct ubi_scan_leb, u.rb); rb_erase(&seb->u.rb, &sv->root); list_add_tail(&seb->u.list, &si->erase); } rb_erase(&sv->rb, &si->volumes); kfree(sv); si->vols_found -= 1; } /** * ubi_scan_erase_peb - erase a physical eraseblock. * @ubi: UBI device description object * @si: scanning 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. */ int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si, 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 * @si: scanning 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_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi, struct ubi_scan_info *si) { int err = 0; struct ubi_scan_leb *seb, *tmp_seb; if (!list_empty(&si->free)) { seb = list_entry(si->free.next, struct ubi_scan_leb, u.list); list_del(&seb->u.list); dbg_bld("return free PEB %d, EC %d", seb->pnum, seb->ec); return seb; } /* * 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(seb, tmp_seb, &si->erase, u.list) { if (seb->ec == UBI_SCAN_UNKNOWN_EC) seb->ec = si->mean_ec; err = ubi_scan_erase_peb(ubi, si, seb->pnum, seb->ec+1); if (err) continue; seb->ec += 1; list_del(&seb->u.list); dbg_bld("return PEB %d, EC %d", seb->pnum, seb->ec); return seb; } 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 scanning information. * @ubi: UBI device description object * @si: scanning 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_scan_info *si, 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. */ si->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: si->empty_peb_count += 1; return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 0, &si->erase); case UBI_IO_FF_BITFLIPS: si->empty_peb_count += 1; return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 1, &si->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. */ si->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(si, pnum, ec, 1, &si->erase); else /* This is an unexpected corruption */ err = add_corrupted(si, pnum, ec); if (err) return err; goto adjust_mean_ec; case UBI_IO_FF_BITFLIPS: err = add_to_list(si, pnum, ec, 1, &si->erase); if (err) return err; goto adjust_mean_ec; case UBI_IO_FF: if (ec_err) err = add_to_list(si, pnum, ec, 1, &si->erase); else err = add_to_list(si, pnum, ec, 0, &si->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(si, pnum, ec, 1, &si->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(si, pnum, ec, 0, &si->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_scan_add_used(ubi, si, pnum, ec, vidh, bitflips); if (err) return err; adjust_mean_ec: if (!ec_err) { si->ec_sum += ec; si->ec_count += 1; if (ec > si->max_ec) si->max_ec = ec; if (ec < si->min_ec) si->min_ec = ec; } return 0; } /** * check_what_we_have - check what PEB were found by scanning. * @ubi: UBI device description object * @si: scanning 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_scan_info *si) { struct ubi_scan_leb *seb; int max_corr, peb_count; peb_count = ubi->peb_count - si->bad_peb_count - si->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 (si->corr_peb_count) { ubi_err("%d PEBs are corrupted and preserved", si->corr_peb_count); printk(KERN_ERR "Corrupted PEBs are:"); list_for_each_entry(seb, &si->corr, u.list) printk(KERN_CONT " %d", seb->pnum); printk(KERN_CONT "\n"); /* * If too many PEBs are corrupted, we refuse attaching, * otherwise, only print a warning. */ if (si->corr_peb_count >= max_corr) { ubi_err("too many corrupted PEBs, refusing"); return -EINVAL; } } if (si->empty_peb_count + si->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 (si->maybe_bad_peb_count <= 2) { si->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_scan_info *ubi_scan(struct ubi_device *ubi) { int err, pnum; struct rb_node *rb1, *rb2; struct ubi_scan_volume *sv; struct ubi_scan_leb *seb; struct ubi_scan_info *si; si = kzalloc(sizeof(struct ubi_scan_info), GFP_KERNEL); if (!si) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&si->corr); INIT_LIST_HEAD(&si->free); INIT_LIST_HEAD(&si->erase); INIT_LIST_HEAD(&si->alien); si->volumes = RB_ROOT; err = -ENOMEM; si->scan_leb_slab = kmem_cache_create("ubi_scan_leb_slab", sizeof(struct ubi_scan_leb), 0, 0, NULL); if (!si->scan_leb_slab) goto out_si; ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); if (!ech) goto out_si; 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, si, pnum); if (err < 0) goto out_vidh; } dbg_msg("scanning is finished"); /* Calculate mean erase counter */ if (si->ec_count) si->mean_ec = div_u64(si->ec_sum, si->ec_count); err = check_what_we_have(ubi, si); if (err) goto out_vidh; /* * In case of unknown erase counter we use the mean erase counter * value. */ ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) { ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) if (seb->ec == UBI_SCAN_UNKNOWN_EC) seb->ec = si->mean_ec; } list_for_each_entry(seb, &si->free, u.list) { if (seb->ec == UBI_SCAN_UNKNOWN_EC) seb->ec = si->mean_ec; } list_for_each_entry(seb, &si->corr, u.list) if (seb->ec == UBI_SCAN_UNKNOWN_EC) seb->ec = si->mean_ec; list_for_each_entry(seb, &si->erase, u.list) if (seb->ec == UBI_SCAN_UNKNOWN_EC) seb->ec = si->mean_ec; err = paranoid_check_si(ubi, si); if (err) goto out_vidh; ubi_free_vid_hdr(ubi, vidh); kfree(ech); return si; out_vidh: ubi_free_vid_hdr(ubi, vidh); out_ech: kfree(ech); out_si: ubi_scan_destroy_si(si); return ERR_PTR(err); } /** * destroy_sv - free the scanning volume information * @sv: scanning volume information * @si: scanning information * * This function destroys the volume RB-tree (@sv->root) and the scanning * volume information. */ static void destroy_sv(struct ubi_scan_info *si, struct ubi_scan_volume *sv) { struct ubi_scan_leb *seb; struct rb_node *this = sv->root.rb_node; while (this) { if (this->rb_left) this = this->rb_left; else if (this->rb_right) this = this->rb_right; else { seb = rb_entry(this, struct ubi_scan_leb, u.rb); this = rb_parent(this); if (this) { if (this->rb_left == &seb->u.rb) this->rb_left = NULL; else this->rb_right = NULL; } kmem_cache_free(si->scan_leb_slab, seb); } } kfree(sv); } /** * ubi_scan_destroy_si - destroy scanning information. * @si: scanning information */ void ubi_scan_destroy_si(struct ubi_scan_info *si) { struct ubi_scan_leb *seb, *seb_tmp; struct ubi_scan_volume *sv; struct rb_node *rb; list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) { list_del(&seb->u.list); kmem_cache_free(si->scan_leb_slab, seb); } list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) { list_del(&seb->u.list); kmem_cache_free(si->scan_leb_slab, seb); } list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) { list_del(&seb->u.list); kmem_cache_free(si->scan_leb_slab, seb); } list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) { list_del(&seb->u.list); kmem_cache_free(si->scan_leb_slab, seb); } /* Destroy the volume RB-tree */ rb = si->volumes.rb_node; while (rb) { if (rb->rb_left) rb = rb->rb_left; else if (rb->rb_right) rb = rb->rb_right; else { sv = rb_entry(rb, struct ubi_scan_volume, rb); rb = rb_parent(rb); if (rb) { if (rb->rb_left == &sv->rb) rb->rb_left = NULL; else rb->rb_right = NULL; } destroy_sv(si, sv); } } if (si->scan_leb_slab) kmem_cache_destroy(si->scan_leb_slab); kfree(si); } #ifdef CONFIG_MTD_UBI_DEBUG /** * paranoid_check_si - check the scanning information. * @ubi: UBI device description object * @si: scanning information * * This function returns zero if the scanning information is all right, and a * negative error code if not or if an error occurred. */ static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si) { int pnum, err, vols_found = 0; struct rb_node *rb1, *rb2; struct ubi_scan_volume *sv; struct ubi_scan_leb *seb, *last_seb; uint8_t *buf; if (!ubi->dbg->chk_gen) return 0; /* * At first, check that scanning information is OK. */ ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) { int leb_count = 0; cond_resched(); vols_found += 1; if (si->is_empty) { ubi_err("bad is_empty flag"); goto bad_sv; } if (sv->vol_id < 0 || sv->highest_lnum < 0 || sv->leb_count < 0 || sv->vol_type < 0 || sv->used_ebs < 0 || sv->data_pad < 0 || sv->last_data_size < 0) { ubi_err("negative values"); goto bad_sv; } if (sv->vol_id >= UBI_MAX_VOLUMES && sv->vol_id < UBI_INTERNAL_VOL_START) { ubi_err("bad vol_id"); goto bad_sv; } if (sv->vol_id > si->highest_vol_id) { ubi_err("highest_vol_id is %d, but vol_id %d is there", si->highest_vol_id, sv->vol_id); goto out; } if (sv->vol_type != UBI_DYNAMIC_VOLUME && sv->vol_type != UBI_STATIC_VOLUME) { ubi_err("bad vol_type"); goto bad_sv; } if (sv->data_pad > ubi->leb_size / 2) { ubi_err("bad data_pad"); goto bad_sv; } last_seb = NULL; ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) { cond_resched(); last_seb = seb; leb_count += 1; if (seb->pnum < 0 || seb->ec < 0) { ubi_err("negative values"); goto bad_seb; } if (seb->ec < si->min_ec) { ubi_err("bad si->min_ec (%d), %d found", si->min_ec, seb->ec); goto bad_seb; } if (seb->ec > si->max_ec) { ubi_err("bad si->max_ec (%d), %d found", si->max_ec, seb->ec); goto bad_seb; } if (seb->pnum >= ubi->peb_count) { ubi_err("too high PEB number %d, total PEBs %d", seb->pnum, ubi->peb_count); goto bad_seb; } if (sv->vol_type == UBI_STATIC_VOLUME) { if (seb->lnum >= sv->used_ebs) { ubi_err("bad lnum or used_ebs"); goto bad_seb; } } else { if (sv->used_ebs != 0) { ubi_err("non-zero used_ebs"); goto bad_seb; } } if (seb->lnum > sv->highest_lnum) { ubi_err("incorrect highest_lnum or lnum"); goto bad_seb; } } if (sv->leb_count != leb_count) { ubi_err("bad leb_count, %d objects in the tree", leb_count); goto bad_sv; } if (!last_seb) continue; seb = last_seb; if (seb->lnum != sv->highest_lnum) { ubi_err("bad highest_lnum"); goto bad_seb; } } if (vols_found != si->vols_found) { ubi_err("bad si->vols_found %d, should be %d", si->vols_found, vols_found); goto out; } /* Check that scanning information is correct */ ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) { last_seb = NULL; ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) { int vol_type; cond_resched(); last_seb = seb; err = ubi_io_read_vid_hdr(ubi, seb->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 (sv->vol_type != vol_type) { ubi_err("bad vol_type"); goto bad_vid_hdr; } if (seb->sqnum != be64_to_cpu(vidh->sqnum)) { ubi_err("bad sqnum %llu", seb->sqnum); goto bad_vid_hdr; } if (sv->vol_id != be32_to_cpu(vidh->vol_id)) { ubi_err("bad vol_id %d", sv->vol_id); goto bad_vid_hdr; } if (sv->compat != vidh->compat) { ubi_err("bad compat %d", vidh->compat); goto bad_vid_hdr; } if (seb->lnum != be32_to_cpu(vidh->lnum)) { ubi_err("bad lnum %d", seb->lnum); goto bad_vid_hdr; } if (sv->used_ebs != be32_to_cpu(vidh->used_ebs)) { ubi_err("bad used_ebs %d", sv->used_ebs); goto bad_vid_hdr; } if (sv->data_pad != be32_to_cpu(vidh->data_pad)) { ubi_err("bad data_pad %d", sv->data_pad); goto bad_vid_hdr; } } if (!last_seb) continue; if (sv->highest_lnum != be32_to_cpu(vidh->lnum)) { ubi_err("bad highest_lnum %d", sv->highest_lnum); goto bad_vid_hdr; } if (sv->last_data_size != be32_to_cpu(vidh->data_size)) { ubi_err("bad last_data_size %d", sv->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, sv, &si->volumes, rb) ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) buf[seb->pnum] = 1; list_for_each_entry(seb, &si->free, u.list) buf[seb->pnum] = 1; list_for_each_entry(seb, &si->corr, u.list) buf[seb->pnum] = 1; list_for_each_entry(seb, &si->erase, u.list) buf[seb->pnum] = 1; list_for_each_entry(seb, &si->alien, u.list) buf[seb->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_seb: ubi_err("bad scanning information about LEB %d", seb->lnum); ubi_dump_seb(seb, 0); ubi_dump_sv(sv); goto out; bad_sv: ubi_err("bad scanning information about volume %d", sv->vol_id); ubi_dump_sv(sv); goto out; bad_vid_hdr: ubi_err("bad scanning information about volume %d", sv->vol_id); ubi_dump_sv(sv); ubi_dump_vid_hdr(vidh); out: dump_stack(); return -EINVAL; } #endif /* CONFIG_MTD_UBI_DEBUG */