Re: [RFC] add FIEMAP ioctl to efficiently map file allocation

On Mon, Oct 29, 2007 at 01:45:07PM -0600, Andreas Dilger wrote:

By request on #linuxfs, here is the FIEMAP spec that we used to implement
the FIEMAP support for ext4.  There was an ext4 patch posted on August 29
to linux-ext4 entitled "[PATCH] FIEMAP ioctl".

Link:

http://marc.info/?l=linux-ext4&m=118838241209683&w=2

That's a very ext4 specific ioctl interface. Can we get this made
generic like the FIBMAP interface so we don't have to replicate all
the copyin/copyout handling and interface definitions everywhere?
i.e. a ->extent_map aops callout to the filesystem in generic code
just like ->bmap?

I've asked Kalpak to post
an updated version of that patch along with the changes to the "filefrag"
tool to use FIEMAP.

Where can I find the test program that validates the implementation?
Also, following the fallocate model, can we get the interface definition
turned into a man page before anything is submitted upstream?

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group