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path: root/drivers/mtd/ubi/scan.c
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Diffstat (limited to 'drivers/mtd/ubi/scan.c')
-rw-r--r--drivers/mtd/ubi/scan.c131
1 files changed, 101 insertions, 30 deletions
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index aed19f33b8f3..372a15ac9995 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -44,6 +44,7 @@
#include <linux/slab.h>
#include <linux/crc32.h>
#include <linux/math64.h>
+#include <linux/random.h>
#include "ubi.h"
#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
@@ -72,16 +73,19 @@ static int add_to_list(struct ubi_scan_info *si, int pnum, int ec,
{
struct ubi_scan_leb *seb;
- if (list == &si->free)
+ if (list == &si->free) {
dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
- else if (list == &si->erase)
+ si->free_peb_count += 1;
+ } else if (list == &si->erase) {
dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
- else if (list == &si->corr) {
+ si->erase_peb_count += 1;
+ } else if (list == &si->corr) {
dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
- si->corr_count += 1;
- } else if (list == &si->alien)
+ si->corr_peb_count += 1;
+ } else if (list == &si->alien) {
dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
- else
+ si->alien_peb_count += 1;
+ } else
BUG();
seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
@@ -517,6 +521,7 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
sv->leb_count += 1;
rb_link_node(&seb->u.rb, parent, p);
rb_insert_color(&seb->u.rb, &sv->root);
+ si->used_peb_count += 1;
return 0;
}
@@ -745,19 +750,17 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
bitflips = 1;
else if (err == UBI_IO_PEB_EMPTY)
return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, &si->erase);
- else if (err == UBI_IO_BAD_EC_HDR) {
+ else if (err == UBI_IO_BAD_HDR_READ || err == 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_corr = 1;
+ ec_corr = err;
ec = UBI_SCAN_UNKNOWN_EC;
bitflips = 1;
}
- si->is_empty = 0;
-
if (!ec_corr) {
int image_seq;
@@ -813,9 +816,12 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
return err;
else if (err == UBI_IO_BITFLIPS)
bitflips = 1;
- else if (err == UBI_IO_BAD_VID_HDR ||
+ else if (err == UBI_IO_BAD_HDR_READ || err == UBI_IO_BAD_HDR ||
(err == UBI_IO_PEB_FREE && ec_corr)) {
/* VID header is corrupted */
+ if (err == UBI_IO_BAD_HDR_READ ||
+ ec_corr == UBI_IO_BAD_HDR_READ)
+ si->read_err_count += 1;
err = add_to_list(si, pnum, ec, &si->corr);
if (err)
return err;
@@ -836,11 +842,11 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
switch (vidh->compat) {
case UBI_COMPAT_DELETE:
ubi_msg("\"delete\" compatible internal volume %d:%d"
- " found, remove it", vol_id, lnum);
+ " found, will remove it", vol_id, lnum);
err = add_to_list(si, pnum, ec, &si->corr);
if (err)
return err;
- break;
+ return 0;
case UBI_COMPAT_RO:
ubi_msg("read-only compatible internal volume %d:%d"
@@ -855,7 +861,6 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
err = add_to_list(si, pnum, ec, &si->alien);
if (err)
return err;
- si->alien_peb_count += 1;
return 0;
case UBI_COMPAT_REJECT:
@@ -886,6 +891,85 @@ adjust_mean_ec:
}
/**
+ * 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;
+
+ max_corr = ubi->peb_count - si->bad_peb_count - si->alien_peb_count;
+ max_corr = max_corr / 20 ?: 8;
+
+ /*
+ * Few corrupted PEBs are 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 >= 8) {
+ ubi_warn("%d PEBs are corrupted", si->corr_peb_count);
+ printk(KERN_WARNING "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 this device");
+ return -EINVAL;
+ }
+ }
+
+ if (si->free_peb_count + si->used_peb_count +
+ si->alien_peb_count == 0) {
+ /* No UBI-formatted eraseblocks were found */
+ if (si->corr_peb_count == si->read_err_count &&
+ si->corr_peb_count < 8) {
+ /* No or just few corrupted PEBs, and all of them had a
+ * read error. We assume that those are bad PEBs, which
+ * were just not marked as bad so far.
+ *
+ * This piece of code basically tries to distinguish
+ * between the following 2 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 formating, the faulty PEBs will
+ * probably be marked as bad.
+ *
+ * 2. Flash probably contains non-UBI data and we do
+ * not want to format it and destroy possibly needed
+ * data (e.g., consider the case when the bootloader
+ * MTD partition was accidentally fed to UBI).
+ */
+ 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 possibly contains non-UBI data, "
+ "refusing it");
+ return -EINVAL;
+ }
+ }
+
+ if (si->corr_peb_count > 0)
+ ubi_msg("corrupted PEBs will be formatted");
+ return 0;
+}
+
+/**
* ubi_scan - scan an MTD device.
* @ubi: UBI device description object
*
@@ -909,7 +993,6 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
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);
@@ -935,21 +1018,9 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
if (si->ec_count)
si->mean_ec = div_u64(si->ec_sum, si->ec_count);
- if (si->is_empty)
- ubi_msg("empty MTD device detected");
-
- /*
- * Few corrupted PEBs are 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. Print a warning in this case.
- */
- if (si->corr_count >= 8 || si->corr_count >= ubi->peb_count / 4) {
- ubi_warn("%d PEBs are corrupted", si->corr_count);
- printk(KERN_WARNING "corrupted PEBs are:");
- list_for_each_entry(seb, &si->corr, u.list)
- printk(KERN_CONT " %d", seb->pnum);
- printk(KERN_CONT "\n");
- }
+ err = check_what_we_have(ubi, si);
+ if (err)
+ goto out_vidh;
/*
* In case of unknown erase counter we use the mean erase counter