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    SubjectRe: [PATCH] cowlinks v2

    > > Of course, it gets more interesting if you try to do it at the block
    > > level instead of at the file level. For ext2, you could just reserve
    > > a block #, say -1, to mean take the data from the master cow file, and
    > > anything else is treated normally. You would need a deamon to make
    > > sure you were still saving space though.
    > More interesting is correct. I see the advantages and proposed this
    > myself some time ago, but there are downsides. Basically, for each
    > block you need additional data, at least a counter telling you the
    > number of users it currently has. Eats up memory.
    > If it really has to make sense, you also have to detect duplicated
    > blocks at runtime. So you need a checksum for each block and a
    > balanced tree containing those checksums or some other means of quick
    > access. Eats up 40 bytes (16 checksum, 3*8 tree pointers). With 4k
    > blocks, that's 1% memory overhead.

    Well, you could do this in userspace, do it only if system is idle,
    and use "scan" type approach.

    But I agree that's far away.

    BTW what about the "mix hardlinks with cowlinks" proposal? You said it
    leads to hell and then I did not hear from you. Did it scare you that
    much? ;-)
    When do you have a heart between your knees?
    [Johanka's followup: and *two* hearts?]
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