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>
This commit is contained in:
Artem Bityutskiy
2010-09-03 14:22:17 +03:00
parent 74d82d2660
commit 92e1a7d9e7
4 changed files with 51 additions and 27 deletions

View File

@@ -759,6 +759,16 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
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",