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>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index 37cb18ff10c6..6f9080767e3f 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -748,7 +748,7 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
                 return err;
         else if (err == UBI_IO_BITFLIPS)
                 bitflips = 1;
-        else if (err == UBI_IO_FF)
+        else if (err == UBI_IO_FF || err == UBI_IO_FF_BITFLIPS)
                 return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, &si->erase);
         else if (err == UBI_IO_BAD_HDR_EBADMSG || err == UBI_IO_BAD_HDR) {
                 /*
@@ -817,7 +817,7 @@ static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
         else if (err == UBI_IO_BITFLIPS)
                 bitflips = 1;
         else if (err == UBI_IO_BAD_HDR_EBADMSG || err == UBI_IO_BAD_HDR ||
-                 (err == UBI_IO_FF && ec_corr)) {
+                 (err == UBI_IO_FF && ec_corr) || err == UBI_IO_FF_BITFLIPS) {
                 /* VID header is corrupted */
                 if (err == UBI_IO_BAD_HDR_EBADMSG ||
                     ec_corr == UBI_IO_BAD_HDR_EBADMSG)