diff options
Diffstat (limited to 'drivers/mtd/ubi/scan.c')
| -rw-r--r-- | drivers/mtd/ubi/scan.c | 1368 |
1 files changed, 1368 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c new file mode 100644 index 00000000000..473f3200b86 --- /dev/null +++ b/drivers/mtd/ubi/scan.c @@ -0,0 +1,1368 @@ +/* + * 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 unit. + * + * This unit is responsible for scanning the flash media, checking UBI + * headers and providing complete information about the UBI flash image. + * + * The scanning information is reoresented 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. + * + * Found 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. + */ + +#include <linux/err.h> +#include <linux/crc32.h> +#include "ubi.h" + +#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID +static int paranoid_check_si(const 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; + +int ubi_scan_add_to_list(struct ubi_scan_info *si, int pnum, int ec, + 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->corr) + dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec); + else if (list == &si->alien) + dbg_bld("add to alien: PEB %d, EC %d", pnum, ec); + else + BUG(); + + seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL); + if (!seb) + return -ENOMEM; + + seb->pnum = pnum; + seb->ec = ec; + list_add_tail(&seb->u.list, list); + return 0; +} + +/** + * commit_to_mean_value - commit intermediate results to the final mean erase + * counter value. + * @si: scanning information + * + * This is a helper function which calculates partial mean erase counter mean + * value and adds it to the resulting mean value. As we can work only in + * integer arithmetic and we want to calculate the mean value of erase counter + * accurately, we first sum erase counter values in @si->ec_sum variable and + * count these components in @si->ec_count. If this temporary @si->ec_sum is + * going to overflow, we calculate the partial mean value + * (@si->ec_sum/@si->ec_count) and add it to @si->mean_ec. + */ +static void commit_to_mean_value(struct ubi_scan_info *si) +{ + si->ec_sum /= si->ec_count; + if (si->ec_sum % si->ec_count >= si->ec_count / 2) + si->mean_ec += 1; + si->mean_ec += si->ec_sum; +} + +/** + * validate_vid_hdr - check that volume identifier header is correct and + * consistent. + * @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 unit. 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 = ubi32_to_cpu(vid_hdr->vol_id); + int used_ebs = ubi32_to_cpu(vid_hdr->used_ebs); + int data_pad = ubi32_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_dbg_dump_vid_hdr(vid_hdr); + ubi_dbg_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 == ubi32_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; + si->max_sqnum = 0; + sv->vol_id = vol_id; + sv->root = RB_ROOT; + sv->used_ebs = ubi32_to_cpu(vid_hdr->used_ebs); + sv->data_pad = ubi32_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 then 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(const 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 *vidh = NULL; + unsigned long long sqnum2 = ubi64_to_cpu(vid_hdr->sqnum); + + if (seb->sqnum == 0 && sqnum2 == 0) { + long long abs, v1 = seb->leb_ver, v2 = ubi32_to_cpu(vid_hdr->leb_ver); + + /* + * UBI constantly increases the logical eraseblock version + * number and it can overflow. Thus, we have to bear in mind + * that versions that are close to %0xFFFFFFFF are less then + * versions that are close to %0. + * + * The UBI WL unit guarantees that the number of pending tasks + * is not greater then %0x7FFFFFFF. So, if the difference + * between any two versions is greater or equivalent to + * %0x7FFFFFFF, there was an overflow and the logical + * eraseblock with lower version is actually newer then the one + * with higher version. + * + * FIXME: but this is anyway obsolete and will be removed at + * some point. + */ + + dbg_bld("using old crappy leb_ver stuff"); + + abs = v1 - v2; + if (abs < 0) + abs = -abs; + + if (abs < 0x7FFFFFFF) + /* Non-overflow situation */ + second_is_newer = (v2 > v1); + else + second_is_newer = (v2 < v1); + } else + /* 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. + * + * FIXME: 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 { + pnum = seb->pnum; + + vidh = ubi_zalloc_vid_hdr(ubi); + if (!vidh) + return -ENOMEM; + + err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 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", pnum); + if (err > 0) + err = -EIO; + + goto out_free_vidh; + } + } + + if (!vidh->copy_flag) { + /* It is not a copy, so it is newer */ + dbg_bld("first PEB %d is newer, copy_flag is unset", + pnum); + err = bitflips << 1; + goto out_free_vidh; + } + + vid_hdr = vidh; + } + + /* Read the data of the copy and check the CRC */ + + len = ubi32_to_cpu(vid_hdr->data_size); + buf = kmalloc(len, GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto out_free_vidh; + } + + err = ubi_io_read_data(ubi, buf, pnum, 0, len); + if (err && err != UBI_IO_BITFLIPS) + goto out_free_buf; + + data_crc = ubi32_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; + } + + kfree(buf); + ubi_free_vid_hdr(ubi, vidh); + + 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: + kfree(buf); +out_free_vidh: + ubi_free_vid_hdr(ubi, vidh); + ubi_assert(err < 0); + return err; +} + +/** + * ubi_scan_add_used - add information about a 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 returns zero in case of success and a negative error code in + * case of failure. + */ +int ubi_scan_add_used(const 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; + uint32_t leb_ver; + unsigned long long sqnum; + struct ubi_scan_volume *sv; + struct ubi_scan_leb *seb; + struct rb_node **p, *parent = NULL; + + vol_id = ubi32_to_cpu(vid_hdr->vol_id); + lnum = ubi32_to_cpu(vid_hdr->lnum); + sqnum = ubi64_to_cpu(vid_hdr->sqnum); + leb_ver = ubi32_to_cpu(vid_hdr->leb_ver); + + dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, ver %u, bitflips %d", + pnum, vol_id, lnum, ec, sqnum, leb_ver, bitflips); + + sv = add_volume(si, vol_id, pnum, vid_hdr); + if (IS_ERR(sv) < 0) + return PTR_ERR(sv); + + /* + * 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, " + "LEB ver %u, EC %d", seb->pnum, seb->sqnum, + seb->leb_ver, seb->ec); + + /* + * Make sure that the logical eraseblocks have different + * versions. Otherwise the image is bad. + */ + if (seb->leb_ver == leb_ver && leb_ver != 0) { + ubi_err("two LEBs with same version %u", leb_ver); + ubi_dbg_dump_seb(seb, 0); + ubi_dbg_dump_vid_hdr(vid_hdr); + return -EINVAL; + } + + /* + * Make sure that the logical eraseblocks have different + * sequence numbers. Otherwise the image is bad. + * + * FIXME: remove 'sqnum != 0' check when leb_ver is removed. + */ + if (seb->sqnum == sqnum && sqnum != 0) { + ubi_err("two LEBs with same sequence number %llu", + sqnum); + ubi_dbg_dump_seb(seb, 0); + ubi_dbg_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 then the one + * found earlier. + */ + err = validate_vid_hdr(vid_hdr, sv, pnum); + if (err) + return err; + + if (cmp_res & 4) + err = ubi_scan_add_to_list(si, seb->pnum, + seb->ec, &si->corr); + else + err = ubi_scan_add_to_list(si, seb->pnum, + seb->ec, &si->erase); + if (err) + return err; + + seb->ec = ec; + seb->pnum = pnum; + seb->scrub = ((cmp_res & 2) || bitflips); + seb->sqnum = sqnum; + seb->leb_ver = leb_ver; + + if (sv->highest_lnum == lnum) + sv->last_data_size = + ubi32_to_cpu(vid_hdr->data_size); + + return 0; + } else { + /* + * This logical eraseblock is older then the one found + * previously. + */ + if (cmp_res & 4) + return ubi_scan_add_to_list(si, pnum, ec, + &si->corr); + else + return ubi_scan_add_to_list(si, pnum, ec, + &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 = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL); + if (!seb) + return -ENOMEM; + + seb->ec = ec; + seb->pnum = pnum; + seb->lnum = lnum; + seb->sqnum = sqnum; + seb->scrub = bitflips; + seb->leb_ver = leb_ver; + + if (sv->highest_lnum <= lnum) { + sv->highest_lnum = lnum; + sv->last_data_size = ubi32_to_cpu(vid_hdr->data_size); + } + + if (si->max_sqnum < sqnum) + si->max_sqnum = sqnum; + + 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 information about a particular 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 information about a particular logical + * eraseblock 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 unit 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(const struct ubi_device *ubi, + const struct ubi_scan_info *si, int pnum, int ec) +{ + int err; + struct ubi_ec_hdr *ec_hdr; + + ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); + if (!ec_hdr) + return -ENOMEM; + + 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->ec = cpu_to_ubi64(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 unit 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(const struct ubi_device *ubi, + struct ubi_scan_info *si) +{ + int err = 0, i; + struct ubi_scan_leb *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; + } + + for (i = 0; i < 2; i++) { + struct list_head *head; + struct ubi_scan_leb *tmp_seb; + + if (i == 0) + head = &si->erase; + else + head = &si->corr; + + /* + * We try to erase the first physical eraseblock from the @head + * 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, head, 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 eraseblocks found"); + return ERR_PTR(-ENOSPC); +} + +/** + * process_eb - read UBI headers, check them and add corresponding data + * to the 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 succesfully + * 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 ec; + int err, bitflips = 0, vol_id, ec_corr = 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 unit 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; + else if (err == UBI_IO_BITFLIPS) + bitflips = 1; + else if (err == UBI_IO_PEB_EMPTY) + return ubi_scan_add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, + &si->erase); + else if (err == UBI_IO_BAD_EC_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_corr = 1; + ec = UBI_SCAN_UNKNOWN_EC; + bitflips = 1; + } + + si->is_empty = 0; + + if (!ec_corr) { + /* 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 = ubi64_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_dbg_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; + else if (err == UBI_IO_BITFLIPS) + bitflips = 1; + else if (err == UBI_IO_BAD_VID_HDR || + (err == UBI_IO_PEB_FREE && ec_corr)) { + /* VID header is corrupted */ + err = ubi_scan_add_to_list(si, pnum, ec, &si->corr); + if (err) + return err; + goto adjust_mean_ec; + } else if (err == UBI_IO_PEB_FREE) { + /* No VID header - the physical eraseblock is free */ + err = ubi_scan_add_to_list(si, pnum, ec, &si->free); + if (err) + return err; + goto adjust_mean_ec; + } + + vol_id = ubi32_to_cpu(vidh->vol_id); + if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOL_ID) { + int lnum = ubi32_to_cpu(vidh->lnum); + + /* Unsupported internal volume */ + switch (vidh->compat) { + case UBI_COMPAT_DELETE: + ubi_msg("\"delete\" compatible internal volume %d:%d" + " found, remove it", vol_id, lnum); + err = ubi_scan_add_to_list(si, pnum, ec, &si->corr); + if (err) + return err; + break; + + 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 = ubi_scan_add_to_list(si, pnum, ec, &si->alien); + if (err) + return err; + si->alien_peb_count += 1; + return 0; + + case UBI_COMPAT_REJECT: + ubi_err("incompatible internal volume %d:%d found", + vol_id, lnum); + return -EINVAL; + } + } + + /* Both UBI headers seem to be fine */ + err = ubi_scan_add_used(ubi, si, pnum, ec, vidh, bitflips); + if (err) + return err; + +adjust_mean_ec: + if (!ec_corr) { + if (si->ec_sum + ec < ec) { + commit_to_mean_value(si); + si->ec_sum = 0; + si->ec_count = 0; + } else { + 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; +} + +/** + * 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; + si->is_empty = 1; + + err = -ENOMEM; + ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); + if (!ech) + goto out_si; + + vidh = ubi_zalloc_vid_hdr(ubi); + if (!vidh) + goto out_ech; + + for (pnum = 0; pnum < ubi->peb_count; pnum++) { + cond_resched(); + + dbg_msg("process PEB %d", pnum); + err = process_eb(ubi, si, pnum); + if (err < 0) + goto out_vidh; + } + + dbg_msg("scanning is finished"); + + /* Finish mean erase counter calculations */ + if (si->ec_count) + commit_to_mean_value(si); + + if (si->is_empty) + ubi_msg("empty MTD device detected"); + + /* + * 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) { + if (err > 0) + err = -EINVAL; + 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 + * + * This function destroys the volume RB-tree (@sv->root) and the scanning + * volume information. + */ +static void destroy_sv(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; + } + + kfree(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); + kfree(seb); + } + list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) { + list_del(&seb->u.list); + kfree(seb); + } + list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) { + list_del(&seb->u.list); + kfree(seb); + } + list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) { + list_del(&seb->u.list); + kfree(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(sv); + } + } + + kfree(si); +} + +#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID + +/** + * paranoid_check_si - check if the scanning information is correct and + * consistent. + * @ubi: UBI device description object + * @si: scanning information + * + * This function returns zero if the scanning information is all right, %1 if + * not and a negative error code if an error occurred. + */ +static int paranoid_check_si(const 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; + + /* + * 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 != ubi64_to_cpu(vidh->sqnum)) { + ubi_err("bad sqnum %llu", seb->sqnum); + goto bad_vid_hdr; + } + + if (sv->vol_id != ubi32_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 != ubi32_to_cpu(vidh->lnum)) { + ubi_err("bad lnum %d", seb->lnum); + goto bad_vid_hdr; + } + + if (sv->used_ebs != ubi32_to_cpu(vidh->used_ebs)) { + ubi_err("bad used_ebs %d", sv->used_ebs); + goto bad_vid_hdr; + } + + if (sv->data_pad != ubi32_to_cpu(vidh->data_pad)) { + ubi_err("bad data_pad %d", sv->data_pad); + goto bad_vid_hdr; + } + + if (seb->leb_ver != ubi32_to_cpu(vidh->leb_ver)) { + ubi_err("bad leb_ver %u", seb->leb_ver); + goto bad_vid_hdr; + } + } + + if (!last_seb) + continue; + + if (sv->highest_lnum != ubi32_to_cpu(vidh->lnum)) { + ubi_err("bad highest_lnum %d", sv->highest_lnum); + goto bad_vid_hdr; + } + + if (sv->last_data_size != ubi32_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 = kmalloc(ubi->peb_count, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + memset(buf, 1, ubi->peb_count); + for (pnum = 0; pnum < ubi->peb_count; pnum++) { + err = ubi_io_is_bad(ubi, pnum); + if (err < 0) + return err; + else if (err) + buf[pnum] = 0; + } + + ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) + ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) + buf[seb->pnum] = 0; + + list_for_each_entry(seb, &si->free, u.list) + buf[seb->pnum] = 0; + + list_for_each_entry(seb, &si->corr, u.list) + buf[seb->pnum] = 0; + + list_for_each_entry(seb, &si->erase, u.list) + buf[seb->pnum] = 0; + + list_for_each_entry(seb, &si->alien, u.list) + buf[seb->pnum] = 0; + + 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_dbg_dump_seb(seb, 0); + ubi_dbg_dump_sv(sv); + goto out; + +bad_sv: + ubi_err("bad scanning information about volume %d", sv->vol_id); + ubi_dbg_dump_sv(sv); + goto out; + +bad_vid_hdr: + ubi_err("bad scanning information about volume %d", sv->vol_id); + ubi_dbg_dump_sv(sv); + ubi_dbg_dump_vid_hdr(vidh); + +out: + ubi_dbg_dump_stack(); + return 1; +} + +#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */ |