Re: RFC, 32-bit compat handlers for EXT4_IOC_GROUP_ADD

[Theodore Tso <tytso@mit.edu>]

On Fri, Dec 05, 2008 at 06:02:04PM -0700, Andreas Dilger wrote:
> > How far out of "dev" are we?  I'm leaning towards saying "oh well, would
> > have been nicer the other way" but going ahead and just putting the
> > compat handler into the kernel.
> 
> I would be OK with changing to the "proper" struct layout.  Not being able
> to resize with an older e2fsprogs + newer kernel isn't going to cause any
> serious problems (unlike e.g. not being able to mount or e2fsck "/").
> 
> If we are seriously worried about compatibility, we could add the compat
> handler for 32-bit kernels (should have a different IOC number anyways
> because of the struct size) and add some arbitrary check like:
> 
> #ifdef LINUX_KERNEL_VERSION > KERNEL_VERSION(2,6,40)
> #warning remove this old compat code
> #endif

Given that a bunch of distro's have shipped e2fsprogs 1.41.x which we
advertised as being ext4 compatibility, I think we need to keep the
compatibility code.  If we want to add the complexity for the 32-bit
side, with a 2-3 year timeout, that seems like a reasonable
compromise.

							- Ted