Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Correct message.

Pointed out by: jhb
MFC after: 2 weeks

Don't hardcode md0 in message, use $md instead.

Reported by: Ronald Klop <ronald-freebsd8@klop.yi.org>

- Use $md instead of md0, which fixes tests when md(4) device is already
present.
- Correct message - we create GPT, not MBR.

MFC after: 2 weeks

Add a geli resize subcommand to resize encrypted filesystems prior
to growing the filesystem.

Refuse to attach providers where the metadata provider size is
wrong. This makes post-boot attaches behave consistently with
pre-boot attaches. Also refuse to restore metadata to a provider
of the wrong size without the new -f switch. The new -f switch
forces the metadata restoration despite the provider size, and
updates the provider size in the restored metadata to the correct
value.

Helped by: pjd
Reviewed by: pjd