mkfs.xfs ... lazy-count=1 ... not mountable by older kernels?

["David Sparks" <dave@xxxxxxxxxxxxx>]

Hi all,

Is it expected that filesystems made with lazy-count=1 are not mountable by
older kernels?

I'm installing a system based with install media based on 2.6.19 and mkfs.xfs
2.8.11 (its Gentoo 2007.0).  That mkfs.xfs is old so i copied over a 2.9.4
binary and used that to mkfs the filesystem but its unmountable.  Removing the
lazy-count=1 option makes it mountable.

Is this an expected incompatibility or is mix-n-matching xfsprogs a bad idea?

Thanks!