Re: [PATCH 5/5] ubi: Allow to use read-only UBI volume with not enough PEBs

From	Richard Weinberger <richard@nod.at>
Newsgroups	linux.kernel
Subject	Re: [PATCH 5/5] ubi: Allow to use read-only UBI volume with not enough PEBs
Date	2017-08-06 11:50 +0200
Message-ID	<ubqm6-tU-17@gated-at.bofh.it> (permalink)
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Pali,

Am 25.07.2017 um 16:27 schrieb Pali Rohár:
>> I fear this is not correct, it will disable a legit self-check of UBI volumes.
>> If the read-only volume is corrupted/truncated and you miss PEBs, this
>> check will no longer
>> trigger.
>>
>> Especially when dealing with nanddumps, truncation is a common problem.
> 
> Any idea how to fix it? Or how to handle read-only images which are
> marked for auto-resize?

I'd vote for rejecting images that have auto-resize set when the MTD is read-only.
In fact, using UBI on top of a read-only MTD is very uncommon and not recommended (for NAND).
The auto-resize flag should be also only set when you just have created it using mkfs.ubifs.
Why would you inspect such an image with the kernel UBIFS unless you're hunting down a bug
in mkfs.ubifs?

Thanks,
//richard

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Re: [PATCH 5/5] ubi: Allow to use read-only UBI volume with not  enough PEBs Richard Weinberger <richard@nod.at> - 2017-08-06 11:50 +0200
  Re: [PATCH 5/5] ubi: Allow to use read-only UBI volume with not enough PEBs Pali Rohár <pali.rohar@gmail.com> - 2017-08-06 12:40 +0200

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