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| author | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2010-09-03 14:22:17 +0300 |
|---|---|---|
| committer | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2010-10-19 17:19:56 +0300 |
| commit | 92e1a7d9e7e07fb1cf0cbbcdf202938d0819b54d (patch) | |
| tree | 48930121fa2f1cf9ebd36f85118fe433d1ecd01f /drivers/mtd/ubi/ubi.h | |
| parent | 74d82d2660058e32644f0c673656b2a1d01d3688 (diff) | |
| download | lwn-92e1a7d9e7e07fb1cf0cbbcdf202938d0819b54d.tar.gz lwn-92e1a7d9e7e07fb1cf0cbbcdf202938d0819b54d.zip | |
UBI: handle bit-flips when no header found
Currently UBI has one small flaw - when we read EC or VID header, but find only
0xFF bytes, we return UBI_IO_FF and do not report whether we had bit-flips or
not. In case of the VID header, the scanning code adds this PEB to the free list,
even though there were bit-flips.
Imagine the following situation: we start writing VID header to a PEB and have a
power cut, so the PEB becomes unstable. When we scan and read the PEB, we get
a bit-flip. Currently, UBI would just ignore this and treat the PEB as free. This
patch changes UBI behavior and now UBI will schedule this PEB for erasure.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Diffstat (limited to 'drivers/mtd/ubi/ubi.h')
| -rw-r--r-- | drivers/mtd/ubi/ubi.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h index 774bdcad6a07..10990770bc9e 100644 --- a/drivers/mtd/ubi/ubi.h +++ b/drivers/mtd/ubi/ubi.h @@ -86,17 +86,25 @@ * Error codes returned by the I/O sub-system. * * UBI_IO_FF: the read region of flash contains only 0xFFs + * UBI_IO_FF_BITFLIPS: the same as %UBI_IO_FF, but also also there was a data + * integrity error reported by the MTD driver + * (uncorrectable ECC error in case of NAND) * UBI_IO_BAD_HDR: the EC or VID header is corrupted (bad magic or CRC) * UBI_IO_BAD_HDR_EBADMSG: the same as %UBI_IO_BAD_HDR, but also there was a * data integrity error reported by the MTD driver * (uncorrectable ECC error in case of NAND) * UBI_IO_BITFLIPS: bit-flips were detected and corrected + * + * Note, it is probably better to have bit-flip and ebadmsg as flags which can + * be or'ed with other error code. But this is a big change because there are + * may callers, so it does not worth the risk of introducing a bug */ enum { UBI_IO_FF = 1, + UBI_IO_FF_BITFLIPS, UBI_IO_BAD_HDR, UBI_IO_BAD_HDR_EBADMSG, - UBI_IO_BITFLIPS + UBI_IO_BITFLIPS, }; /* |