Re: OT: why no file copy() libc/syscall ??

[Andreas Dilger]

On Nov 10, 2003  20:05 -0500, Albert Cahalan wrote:
> > It is too simple to implement in user mode.
> 
> That works for a plain byte-stream on a
> local UNIX-style filesystem. (though it
> likely isn't the fastest)
> 
> It doesn't work for Macintosh files.
> It's too slow for CIFS over a modem.
> It doesn't work for Windows security data.
> It doesn't allow copy-on-write files.
> It eats CPU time on compressed filesystems.

Having a sys_copy() syscall would be incredibly useful for Lustre
(distributed Linux fs).  We could start a copy from one storage node
to another (or more likely many to many for a file striped over many
storage nodes) at num_stripes * uni-directional bandwidth with no
impact to the client node.  Instead, we have to copy files at best a
single client's bi-directional network_bandwidth.

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://www-mddsp.enel.ucalgary.ca/People/adilger/

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