[dm-devel] dm-verity: Verification fails but do not see Input/Output Error on read

[Chaitra Bhat]

Hi All,

I am currently experimenting with dm-verity. I was able to successfully set-up a dm-verity target and mount it as a read-only filesystem.

But when I was testing the functionality of dm-verity, I found this. As suggested by Will Drewry in one of his e-mails, I used dd to write over the underlying block device, then tried to dd it out via the dm-verity device. I did not get EIO when I did this.

I then did a veritysetup verify and it said "Verification failed at position x", with 'x' being the position I had modified using dd.

So, any idea why do I not get Input/Output Error message when I know that verification is failing at that location?

(Yes, I did drop the caches before reading)

-Chaitra
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