Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Revert r228695. We use __func__ here as a format to distinguish between
abort and assert. It would be cleaner to use NULL or "" here, but gcc
complains in both cases.

Don't use function name as format string.

Detected by: clang
MFC after: 1 week

Rename pjdlog_verify() to pjdlog_abort() as it better describes what the
the function does and mark it with __dead2.

MFC after: 1 week

Extend pjdlog_verify() to support the following additional macros:
PJDLOG_RVERIFY() - always check expression and on false log the given message
and exit.
PJDLOG_RASSERT() - check expression when NDEBUG is not defined and on false log
given message and exit.
PJDLOG_ABORT() - log the given message and exit.

MFC after: 1 week

Add functions to initialize/finalize pjdlog. This allows to open/close log
file at will.

MFC after: 1 week

Remove __dead2 from pjdlog_verify() prototype, it does return sometimes.

MFC after: 1 week

Use more consistent function name with the others (pjdlogv_prefix_set()
instead of pjdlog_prefix_setv()).

MFC after: 1 week

Problem with assertion is that it logs on stderr. Add two macros:
PJDLOG_ASSERT() and PJDLOG_VERIFY() that will check the given condition
and log the problem where appropriate. The difference between those
two is that PJDLOG_VERIFY() always work and PJDLOG_ASSERT() can be
turned off by defining NDEBUG.

MFC after: 1 month

Please welcome HAST - Highly Avalable Storage.

HAST allows to transparently store data on two physically separated machines
connected over the TCP/IP network. HAST works in Primary-Secondary
(Master-Backup, Master-Slave) configuration, which means that only one of the
cluster nodes can be active at any given time. Only Primary node is able to
handle I/O requests to HAST-managed devices. Currently HAST is limited to two
cluster nodes in total.

HAST operates on block level - it provides disk-like devices in /dev/hast/
directory for use by file systems and/or applications. Working on block level
makes it transparent for file systems and applications. There in no difference
between using HAST-provided device and raw disk, partition, etc. All of them
are just regular GEOM providers in FreeBSD.

For more information please consult hastd(8), hastctl(8) and hast.conf(5)
manual pages, as well as http://wiki.FreeBSD.org/HAST.

Sponsored by: FreeBSD Foundation
Sponsored by: OMCnet Internet Service GmbH
Sponsored by: TransIP BV