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 r260703: zinject must use ioctl(2) compatibility wrapper

MFC r247187,247265,247348,247398,247540,247585,247852,248265,248267
Merge various ZFS improvements and bugfixes

MFC r247187:
Import vendor change to avoid "unitialized variable" warnings.

Illumos ZFS issues:
3522 zfs module should not allow uninitialized variables

MFC r247265:
Merge the ZFS I/O deadman thread from vendor (illumos).
This feature panics the system on hanging ZFS I/O, helps debugging
and resumes failed service.

The panic behavior can be controlled with the loader-only tunables:
vfs.zfs.deadman_enabled (enable or disable panic on stalled ZFS I/O)
vfs.zfs.deadman_synctime (expiration time for stalled ZFS I/O)

By default, ZFS I/O deadman is enabled by default on amd64 and i386
excluding virtual guest machines.

MFC r247348:
Be more verbose on ZFS deadman I/O panic
Patch suggested upstream.

MFC r247398:
Import metaslab_sync() speedup from vendor (illumos).

Illumos ZFS issues:
3552 condensing one space map burns 3 seconds of CPU in spa_sync() thread
3564 spa_sync() spends 5-10% of its time in metaslab_sync() (when not
condensing)
3578 transferring the freed map to the defer map should be constant time
3579 ztest trips assertion in metaslab_weight()

MFC r247540:
Fix the zfs_ioctl compat layer to support zfs_cmd size change introduced
in r247265 (ZFS deadman thread). Both new utilities now support the old
kernel and new kernel properly detects old utilities.

For future backwards compatibility, the vfs.zfs.version.ioctl read-only
sysctl has been introduced. With this sysctl zfs utilities will be able
to detect the ioctl interface version of the currently loaded zfs module.

MFC r247585:
Merge new read-only zfs properties from vendor (illumos)

Illumos ZFS issues:
3588 provide zfs properties for logical (uncompressed) space used and
referenced

MFC r247852:
Import ZFS bpobj bugfix from vendor.

Illumos ZFS issues:
3603 panic from bpobj_enqueue_subobj()
3604 zdb should print bpobjs more verbosely

MFC r248265:
Update zfs.8 manpage date (missing in r247585)

MFC r248267:
Import minor ZFS changes from vendor

Illumos ZFS issues:
3604 zdb should print bpobjs more verbosely (fix zdb hang)
3606 zpool status -x shouldn't warn about old on-disk format

Merge ZFS feature flags support and related bugfixes:
236884, 237001, 237119, 237458, 237972, 238113, 238391, 238422, 238926,
238950, 238951, 239389, 239394, 239620, 239774, 239953, 239958, 239967,
239968, 240063, 240133, 240153, 240303, 240345, 240415, 240955, 241655,
243014, 243505, 243506

MFC r236884:
Introduce "feature flags" for ZFS pools (bump SPA version to 5000).
Add first feature "com.delphix:async_destroy" (asynchronous destroy
of ZFS datasets).
Implement features support in ZFS boot code.

Illumos revisions merged:
13700:2889e2596bd6
13701:1949b688d5fb
2619 asynchronous destruction of ZFS file systems
2747 SPA versioning with zfs feature flags

References:
https://www.illumos.org/issues/2619
https://www.illumos.org/issues/2747

MFC r237001:
Fix ZFS boot with pre-features pools (version <= 28) broken in r236884

MFC r237119 [1]:
Do not remount ZFS dataset if changing canmount property to "on" and
dataset is already mounted.

MFC r237458:
Import Illumos revision 13736:9f1d48e1681f
2901 ZFS receive fails for exabyte sparse files

References:
https://www.illumos.org/issues/2901

MFC r237972:
Expose scrub and resilver tunables.
This allows the user to tune the priority trade-off between scrub/resilver
and other ZFS I/O.

MFC r238113 (pjd):
vdev_io_done stage is not used for ioctls.

MFC r238391:
Change behavior introduced in r237119 to vendor solution

References:
https://www.illumos.org/issues/2883

MFC r238422:
Merge illumos commit 13749:df4cd82e2b60

1796 "ZFS HOLD" should not be used when doing "ZFS SEND" froma read-only pool
2871 support for __ZFS_POOL_RESTRICT used by ZFS test suite
2903 zfs destroy -d does not work
2957 zfs destroy -R/r sometimes fails when removing defer-destroyed snapshot

References:
https://www.illumos.org/issues/1796
https://www.illumos.org/issues/2871
https://www.illumos.org/issues/2903
https://www.illumos.org/issues/2957

MFC r238926:
Partial MFV (illumos-gate 13753:2aba784c276b)
2762 zpool command should have better support for feature flags

References:
https://www.illumos.org/issues/2762

MFC r238950:
Fix reporting of root pool upgrade notice.

MFC r238951:
Fix wrong indent according to style(9)

MFC r239389:
Backport fix for vendor issue #3085
3085 zfs diff panics, then panics in a loop on booting

References:
https://www.illumos.org/issues/3085

MFC r239394:
Update zfs(8) manpage with illumos version of "zfs diff"

Illumos issue:
2399 zfs manual page does not document use of "zfs diff"

References:
https://www.illumos.org/issues/2399

MFC r239620 [2]:
Merge recent vendor changes:
3086 unnecessarily setting DS_FLAG_INCONSISTENT on async destroyed datasets
3090 vdev_reopen() during reguid causes vdev to be treated as corrupt
3102 vdev_uberblock_load() and vdev_validate() may read the wrong label

Referenes:
https://www.illumos.org/issues/3086
https://www.illumos.org/issues/3090
https://www.illumos.org/issues/3102

MFC r239774:
Merge recent vendor changes:
3100 zvol rename fails with EBUSY when dirty
3104 eliminate empty bpobjs
3120 zinject hangs in zfsdev_ioctl() due to uninitialized zc

References:
https://www.illumos.org/issues/3100
https://www.illumos.org/issues/3104
https://www.illumos.org/issues/3120

MFC r239953 (joel):
Mdoc fixes.

MFC r239958 (joel):
Minor mdoc fixes.

MFC r239967 (joel):
Mdoc fixes.

MFC r239968 (joel):
Remove trailing whitespace.

MFC r240063 (gjb):
Add myself to copyright sections, per CDDL license.

MFC r240133:
Merge recent vendor changes and sync code:
1862 incremental zfs receive fails for sparse file > 8PB
3112 ztest does not honor ZFS_DEBUG
3122 zfs destroy filesystem should prefetch blocks
3129 'zpool reopen' restarts resilvers
3130 ztest failure: Assertion failed:
0 == dmu_objset_destroy(name, B_FALSE) (0x0 == 0x10)

References:
https://www.illumos.org/issues/1862
https://www.illumos.org/issues/3112
https://www.illumos.org/issues/3122
https://www.illumos.org/issues/3129
https://www.illumos.org/issues/3130

MFC r240153 (gjb) [3]:
Typo fix and minor word swap.

MFC r240303:
Add assfail() and assfail3() to the opensolaris module.
Remove obsoleted intermediate cddl/compat/opensolaris/sys/debug.h.

MFC r240345 (avg):
zfs: fix sa_modify_attrs handling of variable-sized attributes

- skip length_idx index for a replaced variable-sized attribute
- skip length_idx index for a removed variable-sized attribute
- also re-arranged code to make sure that length_idx is always
incremented for variable-sized attributes
- additionally add an assertion that the number of actually produced
attributes is the same as the expected number of resulting
attributes

MFC r240415:
Merge recent zfs vendor changes, sync code and adjust userland DEBUG.

Illumos issued covered:
1884 Empty "used" field for zfs *space commands
3006 VERIFY[S,U,P] and ASSERT[S,U,P] frequently check if first argument
is zero
3028 zfs {group,user}space -n prints (null) instead of numeric GID/UID
3048 zfs {user,group}space [-s|-S] is broken
3049 zfs {user,group}space -t doesn't really filter the results
3060 zfs {user,group}space -H output isn't tab-delimited
3061 zfs {user,group}space -o doesn't use specified fields order
3064 usr/src/cmd/zpool/zpool_main.c misspells "successful"
3093 zfs {user,group}space's -i is noop
3098 zfs userspace/groupspace fail without saying why when run as non-root

References:
https://www.illumos.org/issues/ + [issue_id]

MFC r240955 (partial):
Merge recent vendor changes in ZFS.

Illumos issued covered:
3139 zdb dies when it tries to determine path of unlinked file
3189 kernel panic in ZFS test suite during hotspare_onoffline_004_neg
3208 moving zpool cross-endian results in incorrect user/group accounting

References:
https://www.illumos.org/issues/ + [issue_id]

MFC r241655:
Add missing initialization for do_prefix.
Corrects porting error in r238391

Vendor issue and changeset reference:
2883 changing "canmount" property to "on" should not always remount dataset
https://www.illumos.org/issues/2883
Changeset 13743:95aba6e49b9f

MFC r243014:
Move zpool-features manual page from section 5 to section 7
and fix references

Reported by: pluknet

MFC r243505:
Illumos 13886:e3261d03efbf

3349 zpool upgrade -V bumps the on disk version number, but leaves
the in core version

References:
https://www.illumos.org/issues/3349

MFC r243506:
zfs sha256 checksum is missing in zfs.8 manpage

PR: kern/167905 [1], kern/170912 [2], kern/170914 [2], doc/171356 [3]

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

Approved by: re (implicit)

Finally... Import the latest open-source ZFS version - (SPA) 28.

Few new things available from now on:

- Data deduplication.
- Triple parity RAIDZ (RAIDZ3).
- zfs diff.
- zpool split.
- Snapshot holds.
- zpool import -F. Allows to rewind corrupted pool to earlier
transaction group.
- Possibility to import pool in read-only mode.

MFC after: 1 month

Properly handle IO with B_FAILFAST
Retry IO once with ZIO_FLAG_TRYHARD before declaring a pool faulted

OpenSolaris revision and Bug IDs:

9725:0bf7402e8022
6843014 ZFS B_FAILFAST handling is broken

Approved by: delphij (mentor)
Obtained from: OpenSolaris (Bug ID 6843014)
MFC after: 3 weeks

Include param.h instead of types.h before mount.h so that the nested
include of param.h can be removed from audit.h.

MFC after: 3 days

Update ZFS from version 6 to 13 and bring some FreeBSD-specific changes.

This bring huge amount of changes, I'll enumerate only user-visible changes:

- Delegated Administration

Allows regular users to perform ZFS operations, like file system
creation, snapshot creation, etc.

- L2ARC

Level 2 cache for ZFS - allows to use additional disks for cache.
Huge performance improvements mostly for random read of mostly
static content.

- slog

Allow to use additional disks for ZFS Intent Log to speed up
operations like fsync(2).

- vfs.zfs.super_owner

Allows regular users to perform privileged operations on files stored
on ZFS file systems owned by him. Very careful with this one.

- chflags(2)

Not all the flags are supported. This still needs work.

- ZFSBoot

Support to boot off of ZFS pool. Not finished, AFAIK.

Submitted by: dfr

- Snapshot properties

- New failure modes

Before if write requested failed, system paniced. Now one
can select from one of three failure modes:
- panic - panic on write error
- wait - wait for disk to reappear
- continue - serve read requests if possible, block write requests

- Refquota, refreservation properties

Just quota and reservation properties, but don't count space consumed
by children file systems, clones and snapshots.

- Sparse volumes

ZVOLs that don't reserve space in the pool.

- External attributes

Compatible with extattr(2).

- NFSv4-ACLs

Not sure about the status, might not be complete yet.

Submitted by: trasz

- Creation-time properties

- Regression tests for zpool(8) command.

Obtained from: OpenSolaris