Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

zfsd: listen for sysevent.fs.zfs instead of misc.fs.zfs

At some point the names of these devd events changed. Probably it
happened when importing OpenZFS. Before that, FreeBSD's sysevent_alloc
method didn't create a "class" nvpair in the event, which led to
log_sysevent using the event's ev_subclass field as its type.

MFC after: 2 weeks
Sponsored by: Axcient
Differential Revision: https://reviews.freebsd.org/D39437

zfsd: add support for hotplugging spares

If you remove an unused spare and then reinsert it, zfsd will now online
it in all pools.

Do not MFC without 2a58b312b62 (but it's ok to MFC that one without this
one).

Submitted by: Ameer Hamza <ahamza@ixsystems.com> (zfsd), Me (tests)
MFC after: 2 weeks
MFC with: 2a58b312b62f908ec92311d1bd8536dbaeb8e55b
Sponsored by: iX Systems, Axcient
Pull Request: https://github.com/freebsd/freebsd-src/pull/697

Merge OpenZFS support in to HEAD.

The primary benefit is maintaining a completely shared
code base with the community allowing FreeBSD to receive
new features sooner and with less effort.

I would advise against doing 'zpool upgrade'
or creating indispensable pools using new
features until this change has had a month+
to soak.

Work on merging FreeBSD support in to what was
at the time "ZFS on Linux" began in August 2018.
I first publicly proposed transitioning FreeBSD
to (new) OpenZFS on December 18th, 2018. FreeBSD
support in OpenZFS was finally completed in December
2019. A CFT for downstreaming OpenZFS support in
to FreeBSD was first issued on July 8th. All issues
that were reported have been addressed or, for
a couple of less critical matters there are
pull requests in progress with OpenZFS. iXsystems
has tested and dogfooded extensively internally.
The TrueNAS 12 release is based on OpenZFS with
some additional features that have not yet made
it upstream.

Improvements include:
project quotas, encrypted datasets,
allocation classes, vectorized raidz,
vectorized checksums, various command line
improvements, zstd compression.

Thanks to those who have helped along the way:
Ryan Moeller, Allan Jude, Zack Welch, and many
others.

Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D25872

Optimize zfsd for the happy case

If there are no damaged pools, then ignore all GEOM events. We only use
them to fix damaged pools. However, still pay attention to ZFS events.

MFC after: 20 days
X-MFC-With: 329284
Sponsored by: Spectra Logic Corp

zfsd: Allow zfsd to work on any type of GEOM provider

cddl/usr.sbin/zfsd/zfsd_event.cc
Remove the check for da and ada devices. This way zfsd can work on md,
geli, glabel, gstripe, etc devices. geli in particular is useful
combined with ZFS. gnop is also useful for simulating drive pulls in
the ZFSD test suite.

Also, eliminate the DevfsEvent class entirely. Move its
responsibilities into GeomEvent. We can get everything we need to know
just from listening to GEOM events.

lib/libdevdctl/event.cc
Fix GeomEvent::DevName for CREATE events. Oddly, the relevant field is
named "cdev" for CREATE events but "devname" for disk events.

MFC after: 3 weeks
Relnotes: Yes (probably worth mentioning the geli part)
Sponsored by: Spectra Logic Corp

Close a memory leak when using zpool_read_all_labels

MFC after: 3 weeks
X-MFC-With: 322854
Sponsored by: Spectra Logic Corp

zfsd(8): Close a race condition when onlining a disk paritition

When inserting a partitioned disk, devfs and geom will announce the whole
disk before they announce the partition. If the partition containing ZFS
extends to one of the disk's extents, then zfsd will see a ZFS label on the
whole disk and attempt to online it. ZFS is smart enough to activate the
partition instead of the whole disk, but only if GEOM has already created
the partition's provider.

cddl/contrib/opensolaris/lib/libzfs/common/libzfs.h
cddl/contrib/opensolaris/lib/libzfs/common/libzfs_import.c
Add a zpool_read_all_labels method. It's similar to
zpool_read_label, but it will return the number of labels found.

cddl/usr.sbin/zfsd/zfsd_event.cc
When processing a DevFS CREATE event, only online a VDEV if we can
read all four ZFS labels.

Reviewed by: mav
MFC after: 3 weeks
Sponsored by: Spectra Logic Corp
Differential Revision: https://reviews.freebsd.org/D11920

zfsd(8), the ZFS fault management daemon

Add zfsd, which deals with hard drive faults in ZFS pools. It manages
hotspares and replements in drive slots that publish physical paths.

cddl/usr.sbin/zfsd
Add zfsd(8) and its unit tests

cddl/usr.sbin/Makefile
Add zfsd to the build

lib/libdevdctl
A C++ library that helps devd clients process events

lib/Makefile
share/mk/bsd.libnames.mk
share/mk/src.libnames.mk
Add libdevdctl to the build. It's a private library, unusable by
out-of-tree software.

etc/defaults/rc.conf
By default, set zfsd_enable to NO

etc/mtree/BSD.include.dist
Add a directory for libdevdctl's include files

etc/mtree/BSD.tests.dist
Add a directory for zfsd's unit tests

etc/mtree/BSD.var.dist
Add /var/db/zfsd/cases, where zfsd stores case files while it's shut
down.

etc/rc.d/Makefile
etc/rc.d/zfsd
Add zfsd's rc script

sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c
Fix the resource.fs.zfs.statechange message. It had a number of
problems:

It was only being emitted on a transition to the HEALTHY state.
That made it impossible for zfsd to take actions based on drives
getting sicker.

It compared the new state to vdev_prevstate, which is the state that
the vdev had the last time it was opened. That doesn't make sense,
because a vdev can change state multiple times without being
reopened.

vdev_set_state contains logic that will change the device's new
state based on various conditions. However, the statechange event
was being posted _before_ that logic took effect. Now it's being
posted after.

Submitted by: gibbs, asomers, mav, allanjude
Reviewed by: mav, delphij
Relnotes: yes
Sponsored by: Spectra Logic Corp, iX Systems
Differential Revision: https://reviews.freebsd.org/D6564