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From:   Richard Weinberger <richard.weinberger@gmail.com>
Date:   Mon, 2 Mar 2020 22:14:32 +0100
Message-ID: <CAFLxGvyYFEiEe108Hf_TO7q0ZsiLPswVsgPBQOU29aFqebD4XA@mail.gmail.com>
Subject: Re: [PATCH] ubifs: Don't discard nodes in recovery when ecc err detected
To:     Zhihao Cheng <chengzhihao1@huawei.com>
Cc:     Richard Weinberger <richard@nod.at>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        "zhangyi (F)" <yi.zhang@huawei.com>, linux-mtd@lists.infradead.org,
        LKML <linux-kernel@vger.kernel.org>
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On Mon, Mar 2, 2020 at 4:58 AM Zhihao Cheng <chengzhihao1@huawei.com> wrote:
> I mean, the uncorrectable ECC error is caused by hardware which may lead
> to corrupted nodes detected in UBIFS. I found uncorretable ECC errors on
> my NAND, in the environment of high temperature and humidity.
>
> At present, UBIFS ignores all EBADMSG errors, so the corrupted node is
> only considered in being caused by unfinished writing. I think UBIFS
> should consider the corrupted area caused by ECC errors in process
> ubifs_recover_leb(). no_more_nodes() will skip a read-write unit. Maybe
> the corrupted area is skipped.

Well, if your NAND data is corrupted by your environment UBIFS cannot
do much. Sure, we can paper over some places but at the end of the day
you will always lose.

What if the UBI VID header becomes unreadable or the root node of the
index tree?

-- 
Thanks,
//richard