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authorLinus Torvalds <torvalds@linux-foundation.org>2010-12-03 09:20:21 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-12-03 09:20:21 -0800
commit88063dd69b124721e18a59535d4f35266fcb867f (patch)
treede699d61190284c91803d48ab22512910c23c720
parentdf9d38ebda762e54ed0b142c2c47b2f57a145ab2 (diff)
parent7ac760c2f78ddd8e1bd633767b01becfbbf96720 (diff)
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Merge branch 'linux-next' of git://git.infradead.org/ubi-2.6
* 'linux-next' of git://git.infradead.org/ubi-2.6: UBI: fix corrupted PEB detection for NOR flash
-rw-r--r--drivers/mtd/ubi/io.c37
-rw-r--r--drivers/mtd/ubi/scan.c4
2 files changed, 29 insertions, 12 deletions
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index c2960ac9f39..811775aa8ee 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -482,10 +482,17 @@ static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
uint32_t data = 0;
struct ubi_vid_hdr vid_hdr;
- addr = (loff_t)pnum * ubi->peb_size + ubi->vid_hdr_aloffset;
+ /*
+ * It is important to first invalidate the EC header, and then the VID
+ * header. Otherwise a power cut may lead to valid EC header and
+ * invalid VID header, in which case UBI will treat this PEB as
+ * corrupted and will try to preserve it, and print scary warnings (see
+ * the header comment in scan.c for more information).
+ */
+ addr = (loff_t)pnum * ubi->peb_size;
err = ubi->mtd->write(ubi->mtd, addr, 4, &written, (void *)&data);
if (!err) {
- addr -= ubi->vid_hdr_aloffset;
+ addr += ubi->vid_hdr_aloffset;
err = ubi->mtd->write(ubi->mtd, addr, 4, &written,
(void *)&data);
if (!err)
@@ -494,18 +501,24 @@ static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
/*
* We failed to write to the media. This was observed with Spansion
- * S29GL512N NOR flash. Most probably the eraseblock erasure was
- * interrupted at a very inappropriate moment, so it became unwritable.
- * In this case we probably anyway have garbage in this PEB.
+ * S29GL512N NOR flash. Most probably the previously eraseblock erasure
+ * was interrupted at a very inappropriate moment, so it became
+ * unwritable. In this case we probably anyway have garbage in this
+ * PEB.
*/
err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
- if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR)
- /*
- * The VID header is corrupted, so we can safely erase this
- * PEB and not afraid that it will be treated as a valid PEB in
- * case of an unclean reboot.
- */
- return 0;
+ if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR) {
+ struct ubi_ec_hdr ec_hdr;
+
+ err1 = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
+ if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR)
+ /*
+ * Both VID and EC headers are corrupted, so we can
+ * safely erase this PEB and not afraid that it will be
+ * treated as a valid PEB in case of an unclean reboot.
+ */
+ return 0;
+ }
/*
* The PEB contains a valid VID header, but we cannot invalidate it.
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index 204345be8e6..79ca304fc4d 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -953,6 +953,10 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
* impossible to distinguish it from a PEB which just
* contains garbage because of a power cut during erase
* operation. So we just schedule this PEB for erasure.
+ *
+ * Besides, in case of NOR flash, we deliberatly
+ * corrupt both headers because NOR flash erasure is
+ * slow and can start from the end.
*/
err = 0;
else