Hi, On Wednesday, 5 May 2021 22:45:09 CEST Mikulas Patocka wrote: > So, we can ask Milan to update the manpage. Yes, that would be fine. However, "integrity recalculate" sounds like recalculating integrity. The newly implemented logic is more of a "integrity wipe" or "integrity reset". What is problematic is that actual functionality from end user point of view is now completely different depending on if you use --allow-discards or not. Without discard you recalculate meta, with discard you reset/wipe meta. > It will receive integrity protection for the newly written data. > > If you create an integrity device and make a filesystem on it, the newly > written data matters. The old data that were on the filesystem before > formatting it don't care and don't need to be protected. One of the current possible use cases with --no-wipe --data-device is that you can use existing device holding data that has no integrity and add integrity to it with detached metadata device in combination with recalculate. Then recalculation can be used in a fashion similar to trust-on-first-use for this specific disk without rewriting the data meaning also no temporary copy is needed. This feature is something I have used a few times as adding integrity in-place can be useful in certain situations especially when dealing with large amounts of data. I am not against the new reset/wipe operation, it is certainly a useful thing to have. This style of initialising metadata would be especially useful with formatting devices supporting discard, as it could be used to avoid unnecessary writes on main data by initialising metadata only (and perhaps also issue discards to underlying device). But I do think this should be a separate, new function in addition to existing recalculation feature, to me they both seem useful in different use cases. Thoughts on this? Thanks, -- Melvin Vermeeren Systems engineer
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