[xfs-masters] [PATCH] fs: Add new pre-allocation ioctls to vfs for compatibility with legacy xfs ioctls

[Jamie Lokier]

Boaz Harrosh wrote:
> I would at least expect a big fat comment explaining what happened to the
> structure on what known ARCHs, and how it is expected to look in memory.
> And a BUILD_BUG_ON to make sure of that.

You may have a point.

Struct layout on some architectures changes between compiler default
ABIs in these implicit-padding cases.  Kernel binary compatibility
will be affected.  It is a good reason why we have explicit padding to
natural alignment normally.