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-rw-r--r--drivers/mtd/ubi/scan.c145
-rw-r--r--drivers/mtd/ubi/scan.h15
-rw-r--r--drivers/mtd/ubi/vtbl.c2
3 files changed, 90 insertions, 72 deletions
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index fba3dc6a97e9..19dc5e04fd61 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -29,7 +29,7 @@
* 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.
+ * 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
@@ -38,6 +38,21 @@
* 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.
+ *
+ * UBI tries to distinguish between 2 types of corruptions.
+ * 1. Corruptions caused by power cuts. These are harmless and 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 are supposed to handle these situations. UBI puts these PEBs to
+ * the head of the @erase list and they are scheduled for erasure.
+ *
+ * 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.
*/
#include <linux/err.h>
@@ -62,23 +77,26 @@ static struct ubi_vid_hdr *vidh;
* @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.
- * Returns zero in case of success and a negative error code in case of
+ * 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,
+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);
- si->free_peb_count += 1;
} else if (list == &si->erase) {
dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
- si->erase_peb_count += 1;
} else if (list == &si->alien) {
dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
si->alien_peb_count += 1;
@@ -91,7 +109,10 @@ static int add_to_list(struct ubi_scan_info *si, int pnum, int ec,
seb->pnum = pnum;
seb->ec = ec;
- list_add_tail(&seb->u.list, list);
+ if (to_head)
+ list_add(&seb->u.list, list);
+ else
+ list_add_tail(&seb->u.list, list);
return 0;
}
@@ -282,8 +303,8 @@ static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
* 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 will work
- * still work, but only if no unclean reboots happened.
+ * 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;
@@ -321,7 +342,7 @@ static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
bitflips = 1;
else {
dbg_err("VID of PEB %d header is bad, but it "
- "was OK earlier", pnum);
+ "was OK earlier, err %d", pnum, err);
if (err > 0)
err = -EIO;
@@ -487,11 +508,8 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
if (err)
return err;
- if (cmp_res & 4)
- err = add_corrupted(si, seb->pnum, seb->ec);
- else
- err = add_to_list(si, seb->pnum, seb->ec,
- &si->erase);
+ err = add_to_list(si, seb->pnum, seb->ec, cmp_res & 4,
+ &si->erase);
if (err)
return err;
@@ -510,10 +528,8 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
* This logical eraseblock is older than the one found
* previously.
*/
- if (cmp_res & 4)
- return add_corrupted(si, pnum, ec);
- else
- return add_to_list(si, pnum, ec, &si->erase);
+ return add_to_list(si, pnum, ec, cmp_res & 4,
+ &si->erase);
}
}
@@ -544,7 +560,6 @@ 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;
}
@@ -776,10 +791,14 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
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:
- return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, &si->erase);
+ si->empty_peb_count += 1;
+ return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 1,
+ &si->erase);
case UBI_IO_BAD_HDR_EBADMSG:
- si->read_err_count += 1;
case UBI_IO_BAD_HDR:
/*
* We have to also look at the VID header, possibly it is not
@@ -855,18 +874,25 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
bitflips = 1;
break;
case UBI_IO_BAD_HDR_EBADMSG:
- si->read_err_count += 1;
+ 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:
case UBI_IO_FF_BITFLIPS:
- err = add_corrupted(si, pnum, ec);
+ 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_corrupted(si, pnum, ec);
+ err = add_to_list(si, pnum, ec, 1, &si->erase);
else
- err = add_to_list(si, pnum, ec, &si->free);
+ err = add_to_list(si, pnum, ec, 0, &si->free);
if (err)
return err;
goto adjust_mean_ec;
@@ -885,7 +911,7 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
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, &si->erase);
+ err = add_to_list(si, pnum, ec, 1, &si->erase);
if (err)
return err;
return 0;
@@ -900,7 +926,7 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
case UBI_COMPAT_PRESERVE:
ubi_msg("\"preserve\" compatible internal volume %d:%d"
" found", vol_id, lnum);
- err = add_to_list(si, pnum, ec, &si->alien);
+ err = add_to_list(si, pnum, ec, 0, &si->alien);
if (err)
return err;
return 0;
@@ -946,19 +972,20 @@ adjust_mean_ec:
static int check_what_we_have(struct ubi_device *ubi, struct ubi_scan_info *si)
{
struct ubi_scan_leb *seb;
- int max_corr;
+ int max_corr, peb_count;
- max_corr = ubi->peb_count - si->bad_peb_count - si->alien_peb_count;
- max_corr = max_corr / 20 ?: 8;
+ peb_count = ubi->peb_count - si->bad_peb_count - si->alien_peb_count;
+ max_corr = peb_count / 20 ?: 8;
/*
- * Few corrupted PEBs are not a problem and may be just a result of
+ * 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 >= 8) {
- ubi_warn("%d PEBs are corrupted", si->corr_peb_count);
- printk(KERN_WARNING "corrupted PEBs are:");
+ 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");
@@ -973,41 +1000,35 @@ static int check_what_we_have(struct ubi_device *ubi, struct ubi_scan_info *si)
}
}
- 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).
- */
+ 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));
+ get_random_bytes(&ubi->image_seq,
+ sizeof(ubi->image_seq));
} else {
- ubi_err("MTD device possibly contains non-UBI data, "
- "refusing it");
+ ubi_err("MTD device is not UBI-formatted and possibly "
+ "contains non-UBI data - refusing it");
return -EINVAL;
}
+
}
- if (si->corr_peb_count > 0)
- ubi_msg("corrupted PEBs will be formatted");
return 0;
}
diff --git a/drivers/mtd/ubi/scan.h b/drivers/mtd/ubi/scan.h
index 0876649318dd..12ac852c993b 100644
--- a/drivers/mtd/ubi/scan.h
+++ b/drivers/mtd/ubi/scan.h
@@ -91,14 +91,13 @@ struct ubi_scan_volume {
* @erase: list of physical eraseblocks which have to be erased
* @alien: list of physical eraseblocks which should not be used by UBI (e.g.,
* those belonging to "preserve"-compatible internal volumes)
- * @used_peb_count: count of used PEBs
* @corr_peb_count: count of PEBs in the @corr list
- * @read_err_count: count of PEBs read with error (%UBI_IO_BAD_HDR_EBADMSG was
- * returned)
- * @free_peb_count: count of PEBs in the @free list
- * @erase_peb_count: count of PEBs in the @erase list
+ * @empty_peb_count: count of PEBs which are presumably empty (contain only
+ * 0xFF bytes)
* @alien_peb_count: count of PEBs in the @alien list
* @bad_peb_count: count of bad physical eraseblocks
+ * @maybe_bad_peb_count: count of bad physical eraseblocks which are not marked
+ * as bad yet, but which look like bad
* @vols_found: number of volumes found during scanning
* @highest_vol_id: highest volume ID
* @is_empty: flag indicating whether the MTD device is empty or not
@@ -119,13 +118,11 @@ struct ubi_scan_info {
struct list_head free;
struct list_head erase;
struct list_head alien;
- int used_peb_count;
int corr_peb_count;
- int read_err_count;
- int free_peb_count;
- int erase_peb_count;
+ int empty_peb_count;
int alien_peb_count;
int bad_peb_count;
+ int maybe_bad_peb_count;
int vols_found;
int highest_vol_id;
int is_empty;
diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
index 14c10bed94ee..3bfe00a94667 100644
--- a/drivers/mtd/ubi/vtbl.c
+++ b/drivers/mtd/ubi/vtbl.c
@@ -366,7 +366,7 @@ write_error:
* Probably this physical eraseblock went bad, try to pick
* another one.
*/
- list_add_tail(&new_seb->u.list, &si->corr);
+ list_add(&new_seb->u.list, &si->erase);
goto retry;
}
kfree(new_seb);
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