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    SubjectRe: Ext2fs and hashed table.

    On Wed, 4 Jun 1997 04:41:23 +0200 (Funky), Matthias Urlichs
    <> said:

    > Hi,
    > Stephen C. Tweedie wrote:
    >> [ extent mapping ]
    >> The main problem with this technique is that it completely falls apart
    >> when you consider Unix semantics for files with holes --- you end up
    >> having to reshuffle the entire extent map any time you insert new data
    >> by writing into a hole. The current plan is simply to convert
    >> on-the-fly from extent mapped to direct indexed block mapping if such
    >> a write occurs.
    > Moving the extent mp around shouldn't be _too_ difficult...

    The trouble is that you have to do it for _every_ write request in the
    hole, unless you do fancy things with the tree and have a sparse map
    --- in which case you're losing a lot of the intended efficiency gain
    anyway. The direct map table seems to be a better idea all round for
    writing into holes.


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