Re: File copy system call proposal

Albert D. Cahalan (acahalan@cs.uml.edu)
Mon, 10 Dec 2001 06:50:54 -0500 (EST)


>> I would like to propose implementing a file copy system call.
>> I expect the initial reaction to such a proposal would be "feature
>> bloat" but I believe some substantial benefits can be seen possibly
>> making it worthwhile, primarily the following:
>>
>> Copy on write:
>
> You want cowlink() syscall, not copy() syscall. If they are on different
> partitions, let userspace do the job.

That looks like a knee-jerk reaction to stuff going in the kernel.
I want maximum survival of non-UNIX metadata and maximum performance
for this common operation. Let's say you are telecommuting, and...

You have mounted an SMB share from a Windows XP server.
You need to copy a file that has NTFS security data.
The file is 99 GB in size, on the far side of a 33.6 kb/s modem link.
Now copy this file!
Better yet, maybe you have two mount points or mounted two shares.

????

Filesystem-specific user tools are abominations BTW. We don't
have reiser-mv, reiser-cp, reiser-gmc, reiser-rm, etc.
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