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>
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index a9e7c9e..605ecb1 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -759,6 +759,16 @@
dbg_wl("PEB %d has no VID header", e1->pnum);
protect = 1;
goto out_not_moved;
+ } else if (err == UBI_IO_FF_BITFLIPS) {
+ /*
+ * The same situation as %UBI_IO_FF, but bit-flips were
+ * detected. It is better to schedule this PEB for
+ * scrubbing.
+ */
+ dbg_wl("PEB %d has no VID header but has bit-flips",
+ e1->pnum);
+ scrubbing = 1;
+ goto out_not_moved;
}
ubi_err("error %d while reading VID header from PEB %d",