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From: Sean Eric Fagan <sef@Kithrup.COM>
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Subject: Re: Tool to access ZFS/NFSv4 alternate data streams on FreeBSD?
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In article <nBnoKs.Es3@kithrup.com> Jordan K. Hubbard writes:
>Well, if someone is willing to add copyfile(3) to FreeBSD (it does all
>the magic) then the OS X versions of tar/pax/cpio/… are just forked
>versions of the FreeBSD tools, but with copyfile(3) support for handling
>(serializing / deserializing) EAs.

copyfile(3)'s serialization sucks -- it's not streamable, and it's limited in
terms of size.

copyfile(3) as an API also has some serious limitations -- callbacks were
added at exactly the wrong time (just before blocks were announced).

On the other hand, it does work.