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Date: Mon, 28 Oct 2019 21:44:05 +0800
From: Gao Xiang <gaoxiang25@huawei.com>
To: Chao Yu <yuchao0@huawei.com>
Subject: Re: [PATCH v4] erofs: support superblock checksum
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Hi Chao,

On Mon, Oct 28, 2019 at 08:36:00PM +0800, Chao Yu wrote:
> On 2019/10/23 16:45, Gao Xiang wrote:

<snip>

> > That is quite a good point. :-)
> > 
> > My first thought is to check the following payloads of sb (e.g, some per-fs
> > metadata should be checked at mount time together. or for small images, check
> > the whole image at the mount time) as well since if we introduce a new feature
> > to some kernel version, forward compatibility needs to be considered. So it's
> > better to make proper scalability, for this case, we have some choices:
> >  1) limit `chksum_blocks' upbound at runtime (e.g. refuse >= 65536 blocks,
> >     totally 256M.)
> >  2) just get rid of the whole `chksum_blocks' mess and checksum the first 4k
> >     at all, don't consider any latter scalability.
> 
> Xiang, sorry for later reply...
> 
> I prefer method 2), let's enable chksum feature only on superblock first,
> chksum_blocks feature can be added later.

Okay, got it. I will resend patch soon.

Thanks,
Gao Xiang

> 
> Thanks,
> 
> > 
> > Some perferred idea about this? I plan to release erofs-utils v1.0 tomorrow
> > and hold up this feature for the next erofs-utils release, but I think we can
> > get it ready for v5.5 since it is not quite complex feature...
> > 
> > Thanks,
> > Gao Xiang
> > 
> > .
> >