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    SubjectRe: [PATCH] UBIFS: compute KSA size and store in superblock
    >
    > I do not have to time to review it now, but please, make sure that the
    > KSA size is according to 'max_leb_cnt' (see the --max-leb-cnt of the
    > mkfs.ubifs tool).

    Ahh, I see now I also need to add the min number of lebs to min_leb_cnt if
    the feature is enabled.

    > Also, think about this use-case in general: you have
    > UBI volume of size X, then the volume is resized to Y > X, then mounted
    > - UBIFS should work and resize itself to Y, up to the 'max_leb_cnt'. If
    > Y > 'max_leb_cnt', we resize only to 'max_leb_cnt'.

    For this case, it should be fine if the KSA is sized to maxlebcnt.
    However, it will remain that size regardless of the real leb_cnt.

    In general, removing KSA blocks is possible, but if datanodes are
    encrypted with keys on those blocks, then they must be re-encrypted with a
    different key on the smaller set (or somehow write the new last KSA block
    containing all the used keys from the removed KSA blocks along with a
    relocation table, but this seems like alot of coding if removing LEBs from
    the KSA isn't that important.)

    Adding LEBs to the KSA is very simple, just add a new entry on the list
    and set all the key states to deleted--after purging will be random data;
    but KSA LEBs are logically-sequential, so if it comes from used main LEBs
    the data nodes need to be relocated. or some complicated code structure
    involved in determining where a key for an out-of-range KSA block is
    remapped.

    Cheers,
    Joel Reardon


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