Re: [RFC][PATCH 0/3] ext4: online defrag (ver 1.0)

[Greg Freemyer <greg.freemyer@gmail.com>]

On Wed, Feb 4, 2009 at 9:09 AM, Theodore Tso <tytso@mit.edu> wrote:
> On Wed, Feb 04, 2009 at 05:07:48PM +0900, Akira Fujita wrote:
>>> Do we want the ioctl name to be specific to defrag?  I thought Ted's
>>> goal was to make it more generic?  I can also envision this same ioctl
>>> being implemented by other file systems so EXT4 seems an inappropriate
>>> prefix.
>
> When I said generic I meant in terms of decomposing the functionality
> into multiple ioctls which each could be useful for multiple purposes.
> Not necessarily in terms of being used by other filesystem, because
> they will almost certainly have their own requirements.
>
> So for example, primitives like "allocate blocks for this inode from
> this region of the disk", or "don't allocate blocks for any inode in
> this region of disk", can be used for multiple things (such as on-line
> shrink), and not just defragmentation.
>
> I don't want to move this to the VFS layer, since it will involve huge
> amounts of time while people argue over generic issues regarding the
> interface.  Look at how long it took to settle on the FIEMAP
> interface; that's not an experience I care to repeat.

Convinced and request withdrawn.

Talking about this ioctl, can anyone say:

If the OHSM team implements a similar ioctl for ext2 and ext3 and
submits them for mainline at some point, do they have a chance of
being accepted or are ext2 and ext3 feature frozen?

Thanks
Greg
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