As I told many people at Vault last week, I wrote a document
outlining how we should modify the on-disk structures of XFS to
support host aware SMR drives on the (long) plane flights to Boston.
TL;DR: not a lot of change to the XFS kernel code is required, no
specific SMR awareness is needed by the kernel code. Only
relatively minor tweaks to the on-disk format will be needed and
most of the userspace changes are relatively straight forward, too.
The source for that document can be found in this git tree here:
in the file design/xfs-smr-structure.asciidoc. Alternatively,
pull it straight from cgit:
Or there is a pdf version built from the current TOT on the xfs.org