MFC r328108:

gnop(8): add the ability to set a nop provider's physical path

While I'm here, expand the existing tests a bit.

Differential Revision: https://reviews.freebsd.org/D13579

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Make geom_nop(4) collect statistics on all types of BIOs, not just
reads and writes.

PR: kern/198405
Submitted by: Matthew D. Fuller <fullermd at over-yonder dot net>
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3679

Add a way to specify stripesize and stripeoffset to gnop(8). This makes
it possible to "simulate" 4K media, to eg test alignment handling.

Reviewed by: mav@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3664

use .Mt to mark up email addresses consistently (part1)

PR: 191174
Submitted by: Franco Fichtner <franco@lastsummer.de>

update information about debugging sysctl...

MFC after: 1 week

Fix the example, -w is the right switch for write failure probability.

PR: 136219
Submitted by: Kouki Hashimoto <hsmtkk@gmail.com>
Patch by: gavin
MFC after: 3 days

Minor language cleanup.

MFC after: 3 days

Markup fixes.

- Split failure probability configuration into read failure probability and
write failure probability.
- Allow to specify an error number to return of failure.

MFC after: 3 days

Teach NOP GEOM class how to gather the following statistics:
- number of read I/O requests,
- number of write I/O requests,
- number of read bytes,
- number of written bytes.
Add 'reset' subcommand for resetting statistics.

Instead of documenting every standard subcommand's argument everywhere,
just leave reference to geom(8).

MFC after: 1 week

- Document 'status' subcommand.
- Update copyrights.

MFC after: 1 week

Sort sections.

Added the EXIT STATUS section where appropriate.

Fix arguments syntax.

Manual pages fixes by: ru
MFC after: 3 days

Grammatical and spelling improvements.

Reviewed by: pjd

- Add '-S' option, which allow to specify sector size for transparent
provider.
- Bump version number.

This allows for a quite interesting trick. One can setup a stripe with
stripe size of 512 bytes and create transparent provider on top of it
with sector size equal to <ndisks> * 512. The result will be something
like RAID3 without parity disk (every access will touch all disks).

Fix typo.

MFp4: Add two options for gnop(8)'s 'create' command:
-o offset - specifies where to start on the original provider
-s size - specifies size of the transparent provider

Document sysctl variables.

Based on: simon's patch

Slight markup and grammar fixes.

Fix copy&paste bug.

Fix typo.

- Add a cross-reference to geom(8).
- Add missing 'a'.

Actually we are also able to list only choosen providers.

Be more precise.

Force commit to note, that those manual pages were...

Reviewed by: simon

Add manual pages for gconcat(8), gstripe(8) and gnop(8) utilities.

Supported by: Wheel - Open Technologies - http://www.wheel.pl