Hi Richard,
On Wed, 24 Aug 2016 14:36:13 +0200
Richard Weinberger <richard@xxxxxx> wrote:
> When Fastmap is used we can face here an -EBADMSG
> since Fastmap cannot know about unmaps.
> If the erasure was interrupted the PEB may show ECC
> errors and UBI would go to ro-mode as it assumes
> that the PEB was check during attach time, which is
> not the case with Fastmap.
>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Fixes: dbb7d2a88d ("UBI: Add fastmap core")
> Signed-off-by: Richard Weinberger <richard@xxxxxx>
> ---
> drivers/mtd/ubi/wl.c | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
> index f453326..b419c7c 100644
> --- a/drivers/mtd/ubi/wl.c
> +++ b/drivers/mtd/ubi/wl.c
> @@ -644,7 +644,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
> int shutdown)
> {
> int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;
> - int vol_id = -1, lnum = -1;
> + int erase = 0, keep = 0, vol_id = -1, lnum = -1;
> #ifdef CONFIG_MTD_UBI_FASTMAP
> int anchor = wrk->anchor;
> #endif
> @@ -780,6 +780,16 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
> e1->pnum);
> scrubbing = 1;
> goto out_not_moved;
> + } else if (ubi->fast_attach && err == UBI_IO_BAD_HDR_EBADMSG) {
> + /*
> + * While a full scan would detect interrupted erasures
> + * at attach time we can face them here when attached from
> + * Fastmap.
> + */
> + dbg_wl("PEB %d has ECC errors, maybe from an interrupted erasure",
> + e1->pnum);
> + erase = 1;
> + goto out_not_moved;
Is this really safe to consider all blocks with a corrupted VID header
as a valid corruption caused by a power-cut?
What if the corruption happened afterward?
I'm asking this question, but I actually don't have any solution apart
flagging each scanned PEB, which brings a non-negligible overhead (a
bitmap marking already scanned PEBs).
> }
>
> ubi_err(ubi, "error %d while reading VID header from PEB %d",
> @@ -815,6 +825,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
> * Target PEB had bit-flips or write error - torture it.
> */
> torture = 1;
> + keep = 1;
> goto out_not_moved;
> }
>
> @@ -901,7 +912,7 @@ out_not_moved:
> ubi->erroneous_peb_count += 1;
> } else if (scrubbing)
> wl_tree_add(e1, &ubi->scrub);
> - else
> + else if (keep)
> wl_tree_add(e1, &ubi->used);
> if (dst_leb_clean) {
> wl_tree_add(e2, &ubi->free);
> @@ -922,6 +933,12 @@ out_not_moved:
> goto out_ro;
> }
>
> + if (erase) {
> + err = do_sync_erase(ubi, e1, vol_id, lnum, 1);
> + if (err)
> + goto out_ro;
> + }
> +
> mutex_unlock(&ubi->move_mutex);
> return 0;
>
--
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