Add concurrent I/O support to gnu dd

[Matt Harden]

I'd like to suggest adding the ability to dd(1) to open the file in
concurrent I/O mode.  This applies only to AIX systems and the JFS2
filesystem.  I had a need to do this and was able to do it easily thanks
to the design of coreutils.  As a sysadmin sometimes you have to open a
file in CIO mode because if any other program has the file open already
in CIO mode, the OS will not allow it to be opened in "normal" mode.
Also when using CIO mode, I/O that is not block-aligned is very slow.
This makes dd a good utility for copying data to/from files in CIO mode.

Anyway, here are some simple patches to coreutils and gnulib that give this
capability to dd.

Thanks,
Matt Harden

coreutils.patch
Description: coreutils.patch

gnulib.patch
Description: gnulib.patch