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    SubjectRe: [PATCH] cowlinks v2
    Hi!

    > > > > > Could you not change it back to a normal inode when refcount becomes 1?
    > > > >
    > > > > You can only do that if the cowid object has a pointer to the last
    > > > > remaining reference to it. That's possible, but more complicated and
    > > > > would incur a little more I/O per cow operation.
    > > >
    > > > You'd have to have pointers to all references to it... because you
    > > > can't tell in advance which one will be the last to go away.
    > >
    > > Exactly. Each of the cow pointers would need to be linked in a doubly
    > > linked list containing them all.
    >
    > I don't like the list idea. Having the extra cowid (I prefer inode)
    > indirection costs a few bytes and one lookup, not much. The list is
    > way too much overhead to get rid of so little in a few cases.

    Nobody likes the "list idea".

    > If you really want to, create a new syscall foldfile() that will
    > remove the indirection for one file, if possible. Then userspace can
    > do the ugly work of scanning for single-linked cowids (or just leave
    > it).

    We could automaticaly remove them when we see them, or on first open(
    O_RDWR) or something, or just leave them alone. Definitely leave them
    alone for first version.
    Pavel
    --
    When do you have a heart between your knees?
    [Johanka's followup: and *two* hearts?]
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