rc+devd: Add growfs_postboot

In VM and cloud environments it is often possible to enlarge virtual
disks; this can be useful, for example, if a system is launched with a
small root disk and it later becomes clear that more space is needed.

On kernels which support run-time resizing of disks (for NVMe, this was
added in November 2025; some other disk types have supported this for
longer) a SIZECHANGE notification is sent to userland via devd.

Add a "nostart" rc.d script (runnable manually but not automatically at
boot time) and a devd script which invokes it when a notification
arrives.  The rc.d script enlarges the "final partition" on partitioned
geoms, or the UFS filesystem or zpool device when triggered on a disk
containing either of those.

Reviewed by:	imp, ziaee
MFC after:	2 weeks
Relnotes:	Disk partitions and filesystems can be enlarged
		automatically when disks grow by setting
		growfs_postboot_enable=YES in /etc/rc.conf.
Sponsored by:	Amazon
Differential Revision:	https://reviews.freebsd.org/D58582

0 files changed, 0 insertions, 0 deletions