Re: [PATCH] xfs: fix wrong struct type in ioctl definition whih cmd XFS_IOC_GETBMAPAX

[Christoph Hellwig]

On Fri, Oct 11, 2019 at 07:14:46PM +0800, yu kuai wrote:
> ioctl expect 'getbmapx' as the 'arg' when the cmd is XFS_IOC_GETBMAPX.
> But the definition in 'xfs_fs.h' is 'getbmap'

Strictly speaking that is true.  But changing this defintion will break
existing userspace given that _IOWR encodes the structure size.  If you
had reported this 16 years earlier we could have fixed it.