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

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

MFC r248721:
GEOM NOP does not touch the data, so pass G_PF_ACCEPT_UNMAPPED flag through.

MFC r248720:
Remove extra bio_data and bio_length copying to child request after calling
g_clone_bio(), that already copied them.

MFC: r227309 (partial)

Mark all SYSCTL_NODEs static that have no corresponding SYSCTL_DECLs.

The SYSCTL_NODE macro defines a list that stores all child-elements of
that node. If there's no SYSCTL_DECL macro anywhere else, there's no
reason why it shouldn't be static.

MFC r243333:

- Don't pass geom and provider names as format strings.
- Add __printflike() attributes.
- Remove an extra argument for the g_new_geomf() call in swapongeom_ev().

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

Approved by: re (implicit)

Include sys/sbuf.h directly.

Reviewed by: pjd

Remove unneeded checks, g_new_xxx functions can not return NULL.

Reviewed by: pjd
MFC after: 1 week

Sector size can not be greater than MAXPHYS.

MFC after: 1 week

Remove redundant check.

MFC after: 1 week

Round GNOP provider's mediasize to its sectorsize. This prevents KASSERT
in g_io_request when geom classes doing tasting.

PR: kern/147852
MFC after: 1 week

Remove trailing spaces.

Fix format character.

Reported by: andre

- 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

Remove trailing spaces.

Log situation when EIO is returned.

Remove bio leak when EIO error is emulated.

Found by: Coverity Prevent(tm)
MFC after: 3 days

MFp4: Typo fix (without it the XML GEOM tree wasn't consistent).

Reported by: Eric Anderson <anderson@centtech.com>

Fix build breakage by fixing typo.

Reported by: glebius

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.

g_nop_create: destroy newly created provider in case of errors.

NOP class doesn't operate on metadata, so the spoil event can be safely
ignored.

Tag all geom classes in the tree with a version number.

- Fix unloading by the same way it is done in my other classes:
set gp->softc to NULL and return ENXIO when it is NULL, so GEOM
will not panic or hang, but unload one device on every 'unload'.
This make 'unload' command usable, but it have to be executed
<number of devices> + 1 times.
- Made use of 'pp' variable.

- 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).

Improve geom(8)'s 'list' command to show geoms and their providers and
consumers. Teach STRIPE, CONCAT and NOP classes about this improvement.

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

Fix format string.

Don't allow for duplicated entries creation.

- Change command name from 'config' to 'configure'.
- Bump version number.

Introduce NOP GEOM class. This is totally transparent GEOM class, but
it is very useful for tests. One is able to destroy its provider
forcibly if wants to test how other class handle such events.
One is also able to specify failure probability to check how other
classes handle I/O errors.

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