From 6624ef2ba2e9687929c53fe838910786270cd5c9 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Date: Sun, 26 Jul 2009 15:40:32 +0300
Subject: ubiformat: torture eraseblocks on write errors

When fail to write to PEBs, and the error is EIO, torture the
PEB before marking it as bad. Basically, the code is copied
from the kernel UBI.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
---
 ubi-utils/include/libmtd.h | 19 ++++++++---
 ubi-utils/src/libmtd.c     | 81 ++++++++++++++++++++++++++++++++++++++++++++++
 ubi-utils/src/ubiformat.c  | 12 ++++---
 3 files changed, 103 insertions(+), 9 deletions(-)

diff --git a/ubi-utils/include/libmtd.h b/ubi-utils/include/libmtd.h
index 8d5bc4f..c8b44e8 100644
--- a/ubi-utils/include/libmtd.h
+++ b/ubi-utils/include/libmtd.h
@@ -148,6 +148,17 @@ int mtd_get_dev_info1(libmtd_t desc, int dev_num, struct mtd_dev_info *mtd);
  */
 int mtd_erase(const struct mtd_dev_info *mtd, int fd, int eb);
 
+/**
+ * mtd_torture - torture an eraseblock.
+ * @mtd: MTD device description object
+ * @fd: MTD device node file descriptor
+ * @eb: eraseblock to torture
+ *
+ * This function tortures eraseblock @eb. Returns %0 in case of success and %-1
+ * in case of failure.
+ */
+int mtd_torture(const struct mtd_dev_info *mtd, int fd, int eb);
+
 /**
  * mtd_is_bad - check if eraseblock is bad.
  * @mtd: MTD device description object
@@ -160,13 +171,13 @@ int mtd_erase(const struct mtd_dev_info *mtd, int fd, int eb);
 int mtd_is_bad(const struct mtd_dev_info *mtd, int fd, int eb);
 
 /**
- * mtd_mark_bad - marks the block as bad.
+ * mtd_mark_bad - mark an eraseblock as bad.
  * @mtd: MTD device description object
  * @fd: MTD device node file descriptor
- * @eb: eraseblock to mark bad
+ * @eb: eraseblock to mark as bad
  *
- * This function marks the eraseblock @eb as bad. Returns %0 if success
- * %-1 if failure
+ * This function marks eraseblock @eb as bad. Returns %0 in case of success and
+ * %-1 in case of failure.
  */
 int mtd_mark_bad(const struct mtd_dev_info *mtd, int fd, int eb);
 
diff --git a/ubi-utils/src/libmtd.c b/ubi-utils/src/libmtd.c
index 4f1ef41..249fa23 100644
--- a/ubi-utils/src/libmtd.c
+++ b/ubi-utils/src/libmtd.c
@@ -798,6 +798,87 @@ int mtd_erase(const struct mtd_dev_info *mtd, int fd, int eb)
 	return ioctl(fd, MEMERASE, &ei);
 }
 
+/* Patterns to write to a physical eraseblock when torturing it */
+static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
+
+/**
+ * check_pattern - check if buffer contains only a certain byte pattern.
+ * @buf: buffer to check
+ * @patt: the pattern to check
+ * @size: buffer size in bytes
+ *
+ * This function returns %1 in there are only @patt bytes in @buf, and %0 if
+ * something else was also found.
+ */
+static int check_pattern(const void *buf, uint8_t patt, int size)
+{
+	int i;
+
+	for (i = 0; i < size; i++)
+		if (((const uint8_t *)buf)[i] != patt)
+			return 0;
+	return 1;
+}
+
+int mtd_torture(const struct mtd_dev_info *mtd, int fd, int eb)
+{
+	int err, i, patt_count;
+	void *buf;
+
+	normsg("run torture test for PEB %d", eb);
+	patt_count = ARRAY_SIZE(patterns);
+
+	buf = malloc(mtd->eb_size);
+	if (!buf) {
+		errmsg("cannot allocate %d bytes of memory", mtd->eb_size);
+		return -1;
+	}
+
+	for (i = 0; i < patt_count; i++) {
+		err = mtd_erase(mtd, fd, eb);
+		if (err)
+			goto out;
+
+		/* Make sure the PEB contains only 0xFF bytes */
+		err = mtd_read(mtd, fd, eb, 0, buf, mtd->eb_size);
+		if (err)
+			goto out;
+
+		err = check_pattern(buf, 0xFF, mtd->eb_size);
+		if (err == 0) {
+			errmsg("erased PEB %d, but a non-0xFF byte found", eb);
+			errno = EIO;
+			goto out;
+		}
+
+		/* Write a pattern and check it */
+		memset(buf, patterns[i], mtd->eb_size);
+		err = mtd_write(mtd, fd, eb, 0, buf, mtd->eb_size);
+		if (err)
+			goto out;
+
+		memset(buf, ~patterns[i], mtd->eb_size);
+		err = mtd_read(mtd, fd, eb, 0, buf, mtd->eb_size);
+		if (err)
+			goto out;
+
+		err = check_pattern(buf, patterns[i], mtd->eb_size);
+		if (err == 0) {
+			errmsg("pattern %x checking failed for PEB %d",
+				patterns[i], eb);
+			errno = EIO;
+			goto out;
+		}
+	}
+
+	err = 0;
+	normsg("PEB %d passed torture test, do not mark it a bad", eb);
+
+out:
+	free(buf);
+	return -1;
+}
+
 int mtd_is_bad(const struct mtd_dev_info *mtd, int fd, int eb)
 {
 	int ret;
diff --git a/ubi-utils/src/ubiformat.c b/ubi-utils/src/ubiformat.c
index 2a62f3b..c15500b 100644
--- a/ubi-utils/src/ubiformat.c
+++ b/ubi-utils/src/ubiformat.c
@@ -530,12 +530,14 @@ static int flash_image(const struct mtd_dev_info *mtd, struct ubi_scan_info *si)
 			if (errno != EIO)
 				goto out_close;
 
-			if (mark_bad(mtd, si, eb)) {
-				normsg("operation incomplete");
-				goto out_close;
+			err = mtd_torture(mtd, args.node_fd, eb);
+			if (err) {
+				if (mark_bad(mtd, si, eb)) {
+					normsg("operation incomplete");
+					goto out_close;
+				}
+				divisor += 1;
 			}
-
-			divisor += 1;
 			continue;
 		}
 		if (++written_ebs >= img_ebs)
-- 
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