[PATCH 16/44 take 2] [UBI] scanning unit implementation
From: Artem Bityutskiy
Date: Sat Feb 17 2007 - 12:07:09 EST
diff -auNrp tmp-from/drivers/mtd/ubi/scan.c tmp-to/drivers/mtd/ubi/scan.c
--- tmp-from/drivers/mtd/ubi/scan.c 1970-01-01 02:00:00.000000000 +0200
+++ tmp-to/drivers/mtd/ubi/scan.c 2007-02-17 18:07:26.000000000 +0200
@@ -0,0 +1,1383 @@
+/*
+ * 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 B. Bityutskiy
+ */
+
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/err.h>
+#include <linux/crc32.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <mtd/ubi-header.h>
+#include "ubi.h"
+#include "alloc.h"
+#include "scan.h"
+#include "io.h"
+#include "misc.h"
+#include "vtbl.h"
+#include "debug.h"
+
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID_SCAN
+static int paranoid_check_si(const struct ubi_info *ubi,
+ struct ubi_scan_info *si);
+#else
+#define paranoid_check_si(ubi, si) 0
+#endif
+
+static int process_eb(const struct ubi_info *ubi,
+ struct ubi_scan_info *si, int pnum);
+static void commit_to_mean_value(struct ubi_scan_info *si);
+
+/* Temporary variables used during scanning */
+static struct ubi_ec_hdr *ech;
+static struct ubi_vid_hdr *vidh;
+
+struct ubi_scan_info *ubi_scan(struct ubi_info *ubi)
+{
+ int err, pnum;
+ struct rb_node *rb1, *rb2;
+ struct ubi_scan_volume *sv;
+ struct ubi_scan_leb *seb;
+ struct ubi_scan_info *si;
+ struct ubi_io_info *io = ubi->io;
+
+ si = ubi_kzalloc(sizeof(struct ubi_scan_info));
+ 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 = ubi_zalloc_ec_hdr(ubi);
+ if (!ech)
+ goto out_si;
+
+ vidh = ubi_zalloc_vid_hdr(ubi);
+ if (!vidh)
+ goto out_ech;
+
+ for (pnum = 0; pnum < io->peb_count; pnum++) {
+ cond_resched();
+
+ err = process_eb(ubi, si, pnum);
+ if (unlikely(err < 0))
+ goto out_vidh;
+ }
+
+ dbg_scan("scanning is finished");
+
+ /* Finish mean erase counter calculations */
+ if (si->ec_count)
+ commit_to_mean_value(si);
+
+ /*
+ * FIXME: this is actually duty of the I/O unit to initialize this, but
+ * MTD does not provide enough information.
+ */
+ io->bad_peb_count = si->bad_peb_count;
+ io->good_peb_count = io->peb_count - io->bad_peb_count;
+
+ if (si->is_empty)
+ ubi_msg("empty MTD device detected");
+
+ /*
+ * In case of unknown erase counter we use the mean erase counter
+ * value.
+ */
+ rb_for_each_entry(rb1, sv, &si->volumes, rb) {
+ cond_resched();
+ rb_for_each_entry(rb2, seb, &sv->root, u.rb)
+ if (seb->ec == NAND_SCAN_UNKNOWN_EC)
+ seb->ec = si->mean_ec;
+ }
+
+ cond_resched();
+ list_for_each_entry(seb, &si->free, u.list)
+ if (seb->ec == NAND_SCAN_UNKNOWN_EC)
+ seb->ec = si->mean_ec;
+
+ cond_resched();
+ list_for_each_entry(seb, &si->corr, u.list)
+ if (seb->ec == NAND_SCAN_UNKNOWN_EC)
+ seb->ec = si->mean_ec;
+
+ cond_resched();
+ list_for_each_entry(seb, &si->erase, u.list)
+ if (seb->ec == NAND_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);
+ ubi_free_ec_hdr(ubi, ech);
+ return si;
+
+out_vidh:
+ ubi_free_vid_hdr(ubi, vidh);
+out_ech:
+ ubi_free_ec_hdr(ubi, ech);
+out_si:
+ ubi_scan_destroy_si(si);
+ return ERR_PTR(err);
+}
+
+static int vid_hdr_sanity_check(const struct ubi_info *ubi,
+ const struct ubi_vid_hdr *vid_hdr,
+ const struct ubi_scan_volume *sv, int pnum);
+
+static int add_to_erase(struct ubi_scan_info *si, int pnum, int ec);
+
+static struct ubi_scan_volume *add_volume(const struct ubi_info *ubi,
+ struct ubi_scan_info *si, int vol_id,
+ int pnum,
+ const struct ubi_vid_hdr *vid_hdr);
+
+static int compare_lebs(const struct ubi_info *ubi,
+ const struct ubi_scan_leb *seb, int pnum,
+ const struct ubi_vid_hdr *vid_hdr);
+
+int ubi_scan_add_peb(const struct ubi_info *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;
+ 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);
+ leb_ver = ubi32_to_cpu(vid_hdr->leb_ver);
+
+ dbg_scan("PEB %d, LEB %d:%d, EC %d, LEB ver %u, bitflips %d",
+ pnum, vol_id, lnum, ec, leb_ver, bitflips);
+
+ sv = add_volume(ubi, si, vol_id, pnum, vid_hdr);
+ if (unlikely(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_scan("this LEB already exists: PEB %d, LEB ver %u, EC %d",
+ seb->pnum, seb->leb_ver, seb->ec);
+
+ /*
+ * Make sure that the logical eraseblocks have different
+ * versions. Otherwise the image is bad.
+ */
+ if (unlikely(seb->leb_ver == leb_ver)) {
+ 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;
+ }
+
+ /*
+ * Now we have to drop the older one and preserve the newer
+ * one.
+ */
+ cmp_res = compare_lebs(ubi, seb, pnum, vid_hdr);
+ if (unlikely(cmp_res < 0))
+ return cmp_res;
+
+ if (cmp_res & 1) {
+ /*
+ * This logical eraseblock is newer then the one
+ * found earlier.
+ */
+ err = vid_hdr_sanity_check(ubi, vid_hdr, sv,
+ pnum);
+ if (unlikely(err))
+ return err;
+
+ if (cmp_res & 4)
+ err = ubi_scan_add_corr_peb(si, seb->pnum, seb->ec);
+ else
+ err = add_to_erase(si, seb->pnum, seb->ec);
+ if (unlikely(err))
+ return err;
+
+ seb->ec = ec;
+ seb->pnum = pnum;
+ seb->leb_ver = leb_ver;
+ seb->scrub = ((cmp_res & 2) || bitflips);
+
+ 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_corr_peb(si, pnum, ec);
+ else
+ return add_to_erase(si, pnum, ec);
+ }
+ }
+
+ /*
+ * We've met this logical eraseblock for the first time, add it to the
+ * scanning information.
+ */
+
+ err = vid_hdr_sanity_check(ubi, vid_hdr, sv, pnum);
+ if (unlikely(err))
+ return err;
+
+ seb = ubi_alloc_scan_leb();
+ if (unlikely(!seb))
+ return -ENOMEM;
+
+ seb->ec = ec;
+ seb->pnum = pnum;
+ seb->lnum = lnum;
+ seb->leb_ver = leb_ver;
+ seb->scrub = bitflips;
+
+ if (sv->highest_lnum <= lnum) {
+ sv->highest_lnum = lnum;
+ sv->last_data_size = ubi32_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;
+}
+
+int ubi_scan_add_corr_peb(struct ubi_scan_info *si, int pnum, int ec)
+{
+ struct ubi_scan_leb *seb;
+
+ dbg_scan("PEB %d (EC %d) is corrupted", pnum, ec);
+
+ seb = ubi_alloc_scan_leb();
+ if (unlikely(!seb))
+ return -ENOMEM;
+
+ seb->pnum = pnum;
+ seb->ec = ec;
+ list_add_tail(&seb->u.list, &si->corr);
+ return 0;
+}
+
+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;
+}
+
+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;
+}
+
+void ubi_scan_rm_volume(const struct ubi_info *ubi, struct ubi_scan_info *si,
+ struct ubi_scan_volume *sv)
+{
+ struct rb_node *rb;
+ struct ubi_scan_leb *seb;
+
+ dbg_scan("remove scanning information about volume %d", sv->vol_id);
+
+ while ((rb = rb_first(&sv->root))) {
+ cond_resched();
+
+ seb = rb_entry(rb, struct ubi_scan_leb, u.rb);
+
+ /* The physical eraseblock will be erased later */
+ rb_erase(&seb->u.rb, &sv->root);
+ list_add_tail(&seb->u.list, &si->erase);
+ }
+
+ rb_erase(&sv->rb, &si->volumes);
+ ubi_free_scan_volume(sv);
+ si->vols_found -= 1;
+}
+
+int ubi_scan_erase_peb(const struct ubi_info *ubi,
+ const struct ubi_scan_info *si, int pnum, int ec)
+{
+ int err;
+ struct ubi_ec_hdr *ec_hdr;
+ uint64_t ec1 = ec;
+
+ ec_hdr = ubi_zalloc_ec_hdr(ubi);
+ if (!ec_hdr)
+ return -ENOMEM;
+
+ if (unlikely(ec1 >= UBI_MAX_ERASECOUNTER)) {
+ /*
+ * Erase counter overflow. Upgrade UBI and use 64-bit
+ * erase counters internally.
+ */
+ ubi_err("erase counter overflow at PEB %d, EC %lld",
+ pnum, (long long)ec);
+ return -EINVAL;
+ }
+
+ ec_hdr->ec = cpu_to_ubi64(ec1);
+
+ err = ubi_io_sync_erase(ubi, pnum, 0);
+ if (unlikely(err < 0))
+ goto out_free;
+
+ err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
+
+out_free:
+ ubi_free_ec_hdr(ubi, ec_hdr);
+ return err;
+}
+
+struct ubi_scan_leb *ubi_scan_get_free_peb(const struct ubi_info *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);
+ return seb;
+ }
+
+ if (unlikely(list_empty(&si->erase) && list_empty(&si->corr))) {
+ ubi_err("no vacant eraseblocks found");
+ return ERR_PTR(-ENOSPC);
+ }
+
+ 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) {
+ cond_resched();
+
+ if (seb->ec == NAND_SCAN_UNKNOWN_EC)
+ seb->ec = si->mean_ec;
+
+ err = ubi_scan_erase_peb(ubi, si, seb->pnum,
+ seb->ec + 1);
+ if (unlikely(err))
+ continue;
+
+ seb->ec += 1;
+ list_del(&seb->u.list);
+ dbg_scan("return PEB %d, EC %d", seb->pnum, seb->ec);
+ return seb;
+ }
+ }
+
+ return ERR_PTR(err ? err : -ENOSPC);
+}
+
+static void destroy_sv(struct ubi_scan_volume *sv);
+
+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);
+ ubi_free_scan_leb(seb);
+ }
+ list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {
+ list_del(&seb->u.list);
+ ubi_free_scan_leb(seb);
+ }
+ list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {
+ list_del(&seb->u.list);
+ ubi_free_scan_leb(seb);
+ }
+ list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {
+ list_del(&seb->u.list);
+ ubi_free_scan_leb(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);
+ }
+ }
+
+ ubi_kfree(si);
+}
+
+static int add_to_free(struct ubi_scan_info *si, int pnum, int ec);
+static int add_to_alien(struct ubi_scan_info *si, int pnum);
+
+/**
+ * process_eb - read UBI headers, check them and add corresponding data
+ * to the scanning information.
+ *
+ * @ubi: the UBI device description object
+ * @si: a pointer to the 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(const struct ubi_info *ubi,
+ struct ubi_scan_info *si, int pnum)
+{
+ long long ec;
+ int err, bitflips = 0, vol_id, ec_corr = 0;
+
+ dbg_scan("scan PEB %d", pnum);
+
+ /* Skip bad physical eraseblocks */
+ err = ubi_io_is_bad(ubi, pnum);
+ if (unlikely(err < 0))
+ return err;
+ else if (err) {
+ si->bad_peb_count += 1;
+ return 0;
+ }
+
+ err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
+ if (unlikely(err < 0))
+ return err;
+ else if (unlikely(err == UBI_IO_BITFLIPS))
+ bitflips = 1;
+ else if (err == UBI_IO_PEB_EMPTY)
+ return add_to_erase(si, pnum, NAND_SCAN_UNKNOWN_EC);
+ 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 = NAND_SCAN_UNKNOWN_EC;
+ bitflips = 1;
+ }
+
+ si->is_empty = 0;
+
+ if (!ec_corr) {
+ /* Make sure UBI version is OK */
+ if (unlikely(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 (unlikely(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 (unlikely(err < 0))
+ return err;
+ else if (unlikely(err == UBI_IO_BITFLIPS))
+ bitflips = 1;
+ else if (unlikely(err == UBI_IO_BAD_VID_HDR ||
+ (err == UBI_IO_PEB_FREE && ec_corr))) {
+ /* VID header is corrupted */
+ err = ubi_scan_add_corr_peb(si, pnum, ec);
+ if (err)
+ return err;
+ goto adjust_mean_ec;
+ } else if (err == UBI_IO_PEB_FREE) {
+ /* No VID header - the physical eraseblock is free */
+ err = add_to_free(si, pnum, ec);
+ if (unlikely(err))
+ return err;
+ goto adjust_mean_ec;
+ }
+
+ vol_id = ubi32_to_cpu(vidh->vol_id);
+ if (unlikely(!ubi_ivol_is_known(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_corr_peb(si, pnum, ec);
+ if (unlikely(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->io->ro_mode = 1;
+ break;
+
+ case UBI_COMPAT_PRESERVE:
+ ubi_msg("\"preserve\" compatible internal volume %d:%d"
+ " found", vol_id, lnum);
+ err = add_to_alien(si, pnum);
+ if (unlikely(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_peb(ubi, si, pnum, ec, vidh, bitflips);
+ if (unlikely(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;
+}
+
+/**
+ * add_volume - add a volume tho the scanning information.
+ *
+ * @ubi: the UBI device description object
+ * @si: a pointer to the scanning information
+ * @vol_id: ID of the volume to add
+ * @pnum: physical eraseblock number
+ * @vid_hdr: volume identifier header
+ * @vol_info: a pointer to the corresponding volume scanning information is
+ * returned here.
+ *
+ * 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 the 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(const struct ubi_info *ubi,
+ 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 a volume @vol_id is already
+ * present there.
+ */
+ 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 = ubi_alloc_scan_volume();
+ if (unlikely(!sv))
+ return ERR_PTR(-ENOMEM);
+
+ sv->highest_lnum = sv->leb_count = 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_scan("added volume %d", vol_id);
+ return sv;
+}
+
+/**
+ * compare_lebs - find out which logical eraseblock is newer.
+ *
+ * @ubi: the UBI device description object
+ * @seb: the first logical eraseblock to compare
+ * @pnum: the physical eraseblock number of the second logical eraseblock to
+ * compare
+ * @vid_hdr: the volume identifier header of the second logical eraseblock
+ *
+ * This function compares versions of 2 copies of a LEB and informs which one
+ * is newer. In case of success this function returns a positive value, in case
+ * of error, 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 PEB;
+ * o bit 1 is set: bit-flips were detected in the newer PEB;
+ * o bit 2 is cleared: the older PEB is not corrupted;
+ * o bit 2 is set: the older PEB is not corrupted.
+ */
+static int compare_lebs(const struct ubi_info *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;
+ long long abs, v1 = seb->leb_ver, v2 = ubi32_to_cpu(vid_hdr->leb_ver);
+ struct ubi_vid_hdr *vidh = NULL;
+
+ /*
+ * 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.
+ */
+
+ abs = v1 - v2;
+ if (abs < 0)
+ abs = -abs;
+
+ if (likely(abs < 0x7FFFFFFF))
+ /* Non-overflow situation */
+ second_is_newer = (v2 > v1);
+ else
+ second_is_newer = (v2 < v1);
+
+ /*
+ * 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_scan("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 (unlikely(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_scan("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 = ubi_kmalloc(len);
+ if (unlikely(!buf)) {
+ err = -ENOMEM;
+ goto out_free_vidh;
+ }
+
+ err = ubi_io_read_data(ubi, buf, pnum, 0, len);
+ if (unlikely(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 (unlikely(crc != data_crc)) {
+ dbg_scan("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_scan("PEB %d CRC is OK", pnum);
+ bitflips = !!err;
+ }
+
+ ubi_kfree(buf);
+ ubi_free_vid_hdr(ubi, vidh);
+
+ if (second_is_newer)
+ dbg_scan("second PEB %d is newer, copy_flag is set", pnum);
+ else
+ dbg_scan("first PEB %d is newer, copy_flag is set", pnum);
+
+ return second_is_newer | (bitflips << 1) | (corrupted << 2);
+
+out_free_buf:
+ ubi_kfree(buf);
+out_free_vidh:
+ ubi_free_vid_hdr(ubi, vidh);
+ return err;
+}
+
+/**
+ * add_to_erase - add a physical eraseblock to the list of physical eraseblocks
+ * which have to be erased.
+ *
+ * @si: a pointer to the scanning information
+ * @pnum: the physical eraseblock number
+ * @ec: erase counter of this physical eraseblock
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int add_to_erase(struct ubi_scan_info *si, int pnum, int ec)
+{
+ struct ubi_scan_leb *seb;
+
+ dbg_scan("PEB %d, EC %d", pnum, ec);
+
+ seb = ubi_alloc_scan_leb();
+ if (unlikely(!seb))
+ return -ENOMEM;
+
+ seb->pnum = pnum;
+ seb->ec = ec;
+ list_add_tail(&seb->u.list, &si->erase);
+ return 0;
+}
+
+/**
+ * add_to_alien - add a physical eraseblock to the @si->alien list.
+ *
+ * @si: a pointer to the scanning information
+ * @pnum: the physical eraseblock number
+ *
+ * This function returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+static int add_to_alien(struct ubi_scan_info *si, int pnum)
+{
+ struct ubi_scan_leb *seb;
+
+ dbg_scan("PEB %d is alien", pnum);
+
+ seb = ubi_alloc_scan_leb();
+ if (unlikely(!seb))
+ return -ENOMEM;
+
+ seb->pnum = pnum;
+ list_add_tail(&seb->u.list, &si->alien);
+ return 0;
+}
+
+/**
+ * add_to_free - add a physical eraseblock to the list of free physical
+ * eraseblocks.
+ *
+ * @si: a pointer to the scanning information
+ * @pnum: the physical eraseblock number
+ * @ec: erase counter of this physical eraseblock
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int add_to_free(struct ubi_scan_info *si, int pnum, int ec)
+{
+ struct ubi_scan_leb *seb;
+
+ dbg_scan("PEB %d, EC %d", pnum, ec);
+ ubi_assert(ec >= 0);
+
+ seb = ubi_alloc_scan_leb();
+ if (unlikely(!seb))
+ return -ENOMEM;
+
+ seb->pnum = pnum;
+ seb->ec = ec;
+ list_add_tail(&seb->u.list, &si->free);
+ return 0;
+}
+
+/**
+ * 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;
+ }
+
+ ubi_free_scan_leb(seb);
+ }
+ }
+ ubi_free_scan_volume(sv);
+}
+
+/**
+ * commit_to_mean_value - commit intermediate results to the final mean erase
+ * counter value.
+ *
+ * @si: the scanning information
+ *
+ * This function is a helper function which calculates partial 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)
+{
+ int rem;
+
+ rem = si->ec_sum % si->ec_count;
+ si->ec_sum /= si->ec_count;
+ if (rem >= si->ec_count / 2)
+ si->mean_ec += 1;
+ si->mean_ec += si->ec_sum;
+}
+
+/**
+ * vid_hdr_sanity_check - check that a volume identifier header is sane.
+ *
+ * @ubi: the UBI device description object
+ * @vid_hdr: the volume identifier header to check
+ * @sv: information about the volume this logical eraseblock belongs to
+ * @pnum: the physical eraseblock number the VID header came from
+ *
+ * This function checks that data stored in the volume identifier header
+ * @vid_hdr is consistent. This function 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 this VID header is consistent to information in other VID
+ * headers of the same volume.
+ */
+static int vid_hdr_sanity_check(const struct ubi_info *ubi,
+ 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) {
+ /*
+ * 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 eraseblocks' headers.
+ */
+ int sv_vol_type;
+
+ if (unlikely(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 (unlikely(vol_type != sv_vol_type)) {
+ dbg_err("inconsistent vol_type");
+ goto bad;
+ }
+
+ if (unlikely(used_ebs != sv->used_ebs)) {
+ dbg_err("inconsistent used_ebs");
+ goto bad;
+ }
+
+ if (unlikely(data_pad != sv->data_pad)) {
+ dbg_err("inconsistent data_pad");
+ goto bad;
+ }
+ }
+
+ return 0;
+
+bad:
+ ubi_err("bad VID header at PEB %d", pnum);
+ ubi_dbg_dump_vid_hdr(vid_hdr);
+ ubi_dbg_dump_sv(sv);
+ return -EINVAL;
+}
+
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID_SCAN
+
+/**
+ * paranoid_check_si - check if the scanning information is sane and correct.
+ *
+ * @ubi: the UBI device description object
+ * @si: a pointer to the 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_info *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;
+ const struct ubi_io_info *io = ubi->io;
+ uint8_t *buf;
+
+ /*
+ * At first, check that scanning information is sane.
+ */
+ rb_for_each_entry(rb1, sv, &si->volumes, rb) {
+ int leb_count = 0;
+
+ cond_resched();
+
+ vols_found += 1;
+
+ if (unlikely(si->is_empty)) {
+ ubi_err("bad is_empty flag");
+ goto bad_sv;
+ }
+
+ if (unlikely(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 (unlikely(sv->vol_id >= UBI_MAX_VOLUMES &&
+ sv->vol_id < UBI_INTERNAL_VOL_START)) {
+ ubi_err("bad vol_id");
+ goto bad_sv;
+ }
+
+ if (unlikely(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 (unlikely(sv->vol_type != UBI_DYNAMIC_VOLUME &&
+ sv->vol_type != UBI_STATIC_VOLUME)) {
+ ubi_err("bad vol_type");
+ goto bad_sv;
+ }
+
+ if (unlikely(sv->data_pad > io->leb_size / 2)) {
+ ubi_err("bad data_pad");
+ goto bad_sv;
+ }
+
+ last_seb = NULL;
+ rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
+ cond_resched();
+
+ last_seb = seb;
+ leb_count += 1;
+
+ if (unlikely(seb->pnum < 0 || seb->ec < 0)) {
+ ubi_err("negative values");
+ goto bad_seb;
+ }
+
+ if (unlikely(seb->ec < si->min_ec)) {
+ ubi_err("bad si->min_ec (%d), %d found",
+ si->min_ec, seb->ec);
+ goto bad_seb;
+ }
+
+ if (unlikely(seb->ec > si->max_ec)) {
+ ubi_err("bad si->max_ec (%d), %d found",
+ si->max_ec, seb->ec);
+ goto bad_seb;
+ }
+
+ if (unlikely(seb->pnum >= io->peb_count)) {
+ ubi_err("too high PEB number %d, total PEBs %d",
+ seb->pnum, io->peb_count);
+ goto bad_seb;
+ }
+
+ if (sv->vol_type == UBI_STATIC_VOLUME) {
+ if (unlikely(seb->lnum >= sv->used_ebs)) {
+ ubi_err("bad lnum or used_ebs");
+ goto bad_seb;
+ }
+ } else {
+ if (unlikely(sv->used_ebs != 0)) {
+ ubi_err("non-zero used_ebs");
+ goto bad_seb;
+ }
+ }
+
+ if (unlikely(seb->lnum > sv->highest_lnum)) {
+ ubi_err("incorrect highest_lnum or lnum");
+ goto bad_seb;
+ }
+ }
+
+ if (unlikely(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 (unlikely(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 */
+ rb_for_each_entry(rb1, sv, &si->volumes, rb) {
+ last_seb = NULL;
+ 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 (unlikely(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 (unlikely(sv->vol_type != vol_type)) {
+ ubi_err("bad vol_type");
+ goto bad_vid_hdr;
+ }
+
+ if (unlikely(seb->leb_ver !=
+ ubi32_to_cpu(vidh->leb_ver))) {
+ ubi_err("bad leb_ver %u", seb->leb_ver);
+ goto bad_vid_hdr;
+ }
+
+ if (unlikely(sv->vol_id !=
+ ubi32_to_cpu(vidh->vol_id))) {
+ ubi_err("bad vol_id %d", sv->vol_id);
+ goto bad_vid_hdr;
+ }
+
+ if (unlikely(sv->compat != vidh->compat)) {
+ ubi_err("bad compat %d", vidh->compat);
+ goto bad_vid_hdr;
+ }
+
+ if (unlikely(seb->lnum !=
+ ubi32_to_cpu(vidh->lnum))) {
+ ubi_err("bad lnum %d", seb->lnum);
+ goto bad_vid_hdr;
+ }
+
+ if (unlikely(sv->used_ebs !=
+ ubi32_to_cpu(vidh->used_ebs))) {
+ ubi_err("bad used_ebs %d", sv->used_ebs);
+ goto bad_vid_hdr;
+ }
+
+ if (unlikely(sv->data_pad !=
+ ubi32_to_cpu(vidh->data_pad))) {
+ ubi_err("bad data_pad %d", sv->data_pad);
+ goto bad_vid_hdr;
+ }
+ }
+
+ if (!last_seb)
+ continue;
+
+ if (unlikely(sv->highest_lnum != ubi32_to_cpu(vidh->lnum))) {
+ ubi_err("bad highest_lnum %d", sv->highest_lnum);
+ goto bad_vid_hdr;
+ }
+
+ if (unlikely(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 = ubi_kmalloc(io->peb_count);
+ if (!buf)
+ return -ENOMEM;
+
+ memset(buf, 1, io->peb_count);
+ for (pnum = 0; pnum < io->peb_count; pnum++) {
+ err = ubi_io_is_bad(ubi, pnum);
+ if (unlikely(err < 0))
+ return err;
+ else if (err)
+ buf[pnum] = 0;
+ }
+
+ rb_for_each_entry(rb1, sv, &si->volumes, rb)
+ rb_for_each_entry(rb2, seb, &sv->root, u.rb)
+ buf[seb->pnum] = 0;
+
+ cond_resched();
+ list_for_each_entry(seb, &si->free, u.list)
+ buf[seb->pnum] = 0;
+
+ cond_resched();
+ list_for_each_entry(seb, &si->corr, u.list)
+ buf[seb->pnum] = 0;
+
+ cond_resched();
+ list_for_each_entry(seb, &si->erase, u.list)
+ buf[seb->pnum] = 0;
+
+ cond_resched();
+ list_for_each_entry(seb, &si->alien, u.list)
+ buf[seb->pnum] = 0;
+
+ err = 0;
+ for (pnum = 0; pnum < io->peb_count; pnum++)
+ if (unlikely(buf[pnum])) {
+ ubi_err("PEB %d is not referred", pnum);
+ err = 1;
+ }
+
+ ubi_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_SCAN */
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