MFC r363373:
Fix a memory leak in dsl_scan_visitbp().

PR: 247445

MFC r358339: MFZoL: Fix issue with scanning dedup blocks as scan ends

This patch fixes an issue discovered by ztest where
dsl_scan_ddt_entry() could add I/Os to the dsl scan queues
between when the scan had finished all required work and
when the scan was marked as complete. This caused the scan
to spin indefinitely without ending.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8010
zfsonlinux/zfs@5e0bd0ae056e26de36dee3c199c6fcff8f14ee15

MFC r358337: MFZoL: Fix 2 small bugs with cached dsl_scan_phys_t

This patch corrects 2 small bugs where scn->scn_phys_cached was
not properly updated to match the primary copy when it needed to
be. The first resulted in the pause state not being properly
updated and the second resulted in the cached version being
completely zeroed even if the primary was not.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8010
zfsonlinux/zfs@8cb119e3dc0ac6c90b1517fbadc021b7e9741fc6

MFC r358336, r358340: MFZoL: Fix txg_sync_thread hang in scan_exec_io()

When scn->scn_maxinflight_bytes has not been initialized it's
possible to hang on the condition variable in scan_exec_io().
This issue was uncovered by ztest and is only possible when
deduplication is enabled through the following call path.

txg_sync_thread()
spa_sync()
ddt_sync_table()
ddt_sync_entry()
dsl_scan_ddt_entry()
dsl_scan_scrub_cb()
dsl_scan_enqueuei()
scan_exec_io()
cv_wait()

Resolve the issue by always initializing scn_maxinflight_bytes
to a reasonable minimum value. This value will be recalculated
in dsl_scan_sync() to pick up changes to zfs_scan_vdev_limit
and the addition/removal of vdevs.

Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7098
zfsonlinux/zfs@f90a30ad1b32a971f62a540f8944e42f99b254ce

MFC r352506: fix dsl_scan_ds_clone_swapped logic

PR: 239566

MFC r339237: Fix r336951 mismerge -- use of uninitialized variable.

MFC r337870: Fix mismerge in r337196.

ZoL did the same mistake, and fixed it with separate commit 863522b1f9:

dsl_scan_scrub_cb: don't double-account non-embedded blocks

We were doing count_block() twice inside this function, once
unconditionally at the beginning (intended to catch the embedded block
case) and once near the end after processing the block.

The double-accounting caused the "zpool scrub" progress statistics in
"zpool status" to climb from 0% to 200% instead of 0% to 100%, and
showed double the I/O rate it was actually seeing.

This was apparently a regression introduced in commit 00c405b4b5e8,
which was an incorrect port of this OpenZFS commit:

https://github.com/openzfs/openzfs/commit/d8a447a7

Reviewed by: Thomas Caputi <tcaputi@datto.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Closes #7720
Closes #7738

MFC r337201: Fix build after r337196 mismerge.

MFC r337196: MFV r337195: 9454 ::zfs_blkstats should count embedded blocks

illumos/illumos-gate@dec267e7ea9828898b1c64462daa6636c4ef5e29

Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Matthew Ahrens <mahrens@delphix.com>

MFC r337021: MFV r337020:9443 panic when scrub a v10 pool

illumos/illumos-gate@bb1f424574ac8e08069d0ba993c2a41ffe796794

Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Matthew Ahrens <mahrens@delphix.com>

MFC r336951: MFV r336950: 9290 device removal reduces redundancy of mirrors

Mirrors are supposed to provide redundancy in the face of whole-disk failure
and silent damage (e.g. some data on disk is not right, but ZFS hasn't
detected the whole device as being broken). However, the current device
removal implementation bypasses some of the mirror's redundancy.

illumos/illumos-gate@3a4b1be953ee5601bab748afa07c26ed4996cde6

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prashanth Sreenivasa <pks@delphix.com>
Reviewed by: Sara Hartse <sara.hartse@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Tim Chase <tim@chase2k.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: Matthew Ahrens <mahrens@delphix.com>

MFC r334844, r336180, r336458

r334844

This originated from ZFS On Linux, as
https://github.com/zfsonlinux/zfs/commit/d4a72f23863382bdf6d0ae33196f5b5decbc48fd

During scans (scrubs or resilvers), it sorts the blocks in each transaction
group by block offset; the result can be a significant improvement. (On my
test system just now, which I put some effort to introduce fragmentation into
the pool since I set it up yesterday, a scrub went from 1h2m to 33.5m with the
changes.) I've seen similar rations on production systems.

r336180

Fix up some missed and mis-merges from the sequential scan code
(r334844). Most of the changes involve moving some code around to
reduce conflicts with future merges. One of the missing changes
included a notification on scrub cancellation.

r336458

Fix a couple of typos in r334844 noticed by Richard Kojedzinszky

Approved by: mav
Sponsored by: iXsystems, Inc

MFC r331701: MFV r331695, 331700: 9166 zfs storage pool checkpoint

illumos/illumos-gate@8671400134a11c848244896ca51a7db4d0f69da4

The idea of Storage Pool Checkpoint (aka zpool checkpoint) deals with
exactly that. It can be thought of as a “pool-wide snapshot” (or a
variation of extreme rewind that doesn’t corrupt your data). It remembers
the entire state of the pool at the point that it was taken and the user
can revert back to it later or discard it. Its generic use case is an
administrator that is about to perform a set of destructive actions to ZFS
as part of a critical procedure. She takes a checkpoint of the pool before
performing the actions, then rewinds back to it if one of them fails or puts
the pool into an unexpected state. Otherwise, she discards it. With the
assumption that no one else is making modifications to ZFS, she basically
wraps all these actions into a “high-level transaction”.

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>

MFC r329732: MFV r329502: 7614 zfs device evacuation/removal

illumos/illumos-gate@5cabbc6b49070407fb9610cfe73d4c0e0dea3e77

https://www.illumos.org/issues/7614:
This project allows top-level vdevs to be removed from the storage pool with
“zpool remove”, reducing the total amount of storage in the pool. This
operation copies all allocated regions of the device to be removed onto other
devices, recording the mapping from old to new location. After the removal is
complete, read and free operations to the removed (now “indirect”) vdev must
be remapped and performed at the new location on disk. The indirect mapping
table is kept in memory whenever the pool is loaded, so there is minimal
performance overhead when doing operations on the indirect vdev.

The size of the in-memory mapping table will be reduced when its entries
become “obsolete” because they are no longer used by any block pointers in
the pool. An entry becomes obsolete when all the blocks that use it are
freed. An entry can also become obsolete when all the snapshots that
reference it are deleted, and the block pointers that reference it have been
“remapped” in all filesystems/zvols (and clones). Whenever an indirect block
is written, all the block pointers in it will be “remapped” to their new
(concrete) locations if possible. This process can be accelerated by using
the “zfs remap” command to proactively rewrite all indirect blocks that
reference indirect (removed) vdevs.

Note that when a device is removed, we do not verify the checksum of the data
that is copied. This makes the process much faster, but if it were used on
redundant vdevs (i.e. mirror or raidz vdevs), it would be possible to copy
the wrong data, when we have the correct data on e.g. the other side of the
mirror. Therefore, mirror and raidz devices can not be removed.

Reviewed by: Alex Reece <alex@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Laager <rlaager@wiktel.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Approved by: Garrett D'Amore <garrett@damore.org>
Author: Prashanth Sreenivasa <pks@delphix.com>

MFC r329690: MFV r319737: 6939 add sysevents to zfs core for commands

illumos/illumos-gate@ce1577b04976f1d8bb5f235b6eaaab15b46a3068
https://github.com/illumos/illumos-gate/commit/ce1577b04976f1d8bb5f235b6eaaab15b46a3068

https://www.illumos.org/issues/6939
Originally created https://smartos.org/bugview/OS-4489
sysevents should be fired in the kernel from ZFS whenever a command
is run that is logged in zpool history.
Example output
Terminal 1
root - gz sunos ~ # zfs create zones/foobar
root - gz sunos ~ # zfs set quota=10g zones/foobar
root - gz sunos ~ # zfs destroy zones/foobar
Terminal 2
root - gz sunos ~ # sysevent EC_zfs
nvlist version: 0
date = 2016-04-28T14:50:08.964Z
vendor = SUNW
publisher = zfs
class = EC_zfs
subclass = ESC_ZFS_history_event
pid = 0
data = (embedded nvlist)
nvlist version: 0
pool_name = zones
pool_guid = 0x40c964e8f9a7a694
history_record = (embedded nvlist)
nvlist version: 0
dsname = zones/foobar
dsid = 0x1525
history internal str =
internal_name = create
history txg = 0x4c4ef3

Reviewed by: Patrick Mooney <patrick.mooney@joyent.com>
Reviewed by: Joshua M. Clulow <jmc@joyent.com>
Reviewed by: Josh Wilsdon <jwilsdon@joyent.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed by: Alan Somers <asomers@gmail.com>
Reviewed by: Andrew Stormont <andyjstormont@gmail.com>
Approved by: Matthew Ahrens <mahrens@delphix.com>
Author: Dave Eddy <dave@daveeddy.com>

MFC r328248: MFV r328247:
8959 Add notifications when a scrub is paused or resumed

illumos/illumos-gate@301fd1d6f25595cd8c6d6795f39c72d97aff8cd9

Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Sean Eric Fagan <sef@ixsystems.com>

MFC r323355: MFV r323107: 8414 Implemented zpool scrub pause/resume

illumos/illumos-gate@1702cce751c5cb7ead878d0205a6c90b027e3de8
https://github.com/illumos/illumos-gate/commit/1702cce751c5cb7ead878d0205a6c90b027e3de8

FreeBSD note: rather than merging the zpool.8 update I copied the zpool
scrub section from the illumos zpool.1m to FreeBSD zpool.8 almost
verbatim. Now that the illumos page uses the mdoc format, it was an
easier option. Perhaps the change is not in perfect compliance with the
FreeBSD style, but I think that it is acceptible.

https://www.illumos.org/issues/8414
This issue tracks the port of scrub pause from ZoL: https://github.com/zfsonlinux/zfs/pull/6167
Currently, there is no way to pause a scrub. Pausing may be useful when
the pool is busy with other I/O to preserve bandwidth.

Description

This patch adds the ability to pause and resume scrubbing. This is achieved
by maintaining a persistent on-disk scrub state. While the state is 'paused'
we do not scrub any more blocks. We do however perform regular scan
housekeeping such as freeing async destroyed and deadlist blocks while paused.

Motivation and Context

Scrub pausing can be an I/O intensive operation and people have been asking
for the ability to pause a scrub for a while. This allows one to preserve scrub
progress while freeing up bandwidth for other I/O.

Reviewed by: George Melikov <mail@gmelikov.ru>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Alek Pinchuk <apinchuk@datto.com>

MFC r320156, r320185, r320186, r320262, r320452, r321111:
MFV r318946: 8021 ARC buf data scatter-ization

illumos/illumos-gate@770499e185d15678ccb0be57ebc626ad18d93383
https://github.com/illumos/illumos-gate/commit/770499e185d15678ccb0be57ebc626ad1
8d93383

https://www.illumos.org/issues/8021
The ARC buf data project (known simply as "ABD" since its genesis in the ZoL
community) changes the way the ARC allocates `b_pdata` memory from using linea
r
`void *` buffers to using scatter/gather lists of fixed-size 1KB chunks. This
improves ZFS's performance by helping to defragment the address space occupied
by the ARC, in particular for cases where compressed ARC is enabled. It could
also ease future work to allocate pages directly from `segkpm` for minimal-
overhead memory allocations, bypassing the `kmem` subsystem.
This is essentially the same change as the one which recently landed in ZFS on
Linux, although they made some platform-specific changes while adapting this
work to their codebase:
1. Implemented the equivalent of the `segkpm` suggestion for future work
mentioned above to bypass issues that they've had with the Linux kernel memory
allocator.
2. Changed the internal representation of the ABD's scatter/gather list so it
could be used to pass I/O directly into Linux block device drivers. (This
feature is not available in the illumos block device interface yet.)

FreeBSD notes:
- the actual (default) chunk size is 4KB (despite the text above saying 1KB)
- we can try to reimplement ABDs, so that they are not permanently
mapped into the KVA unless explicitly requested, especially on
platforms with scarce KVA
- we can try to use unmapped I/O and avoid intermediate allocation of a
linear, virtual memory mapped buffer
- we can try to avoid extra data copying by referring to chunks / pages
in the original ABD

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Prashanth Sreenivasa <pks@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Chris Williamson <chris.williamson@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: Dan Kimmel <dan.kimmel@delphix.com>

MFC r319949: MFV r319948: 5428 provide fts(), reallocarray(), and strtonum()

illumos/illumos-gate@4585130b259133a26efae68275dbe56b08366deb
https://github.com/illumos/illumos-gate/commit/4585130b259133a26efae68275dbe56b08366deb

https://www.illumos.org/issues/5428

Most of the upstream change is not applicable to FreeBSD.
Only the renaming of strtonum to zfs_strtonum is relevant to us.
And we already had it partially done.

Reviewed by: Robert Mustacchi <rm@joyent.com>
Approved by: Joshua M. Clulow <josh@sysmgr.org>
Author: Yuri Pankov <yuri.pankov@nexenta.com>

MFC r318935: MFV r318934: 8070 Add some ZFS comments

illumos/illumos-gate@40713f2b249d289022c715107b3951055a63aef0
https://github.com/illumos/illumos-gate/commit/40713f2b249d289022c715107b3951055a63aef0

https://www.illumos.org/issues/8070
Add some ZFS comments left by various developers at different times

Reviewed by: Yuri Pankov <yuri.pankov@gmail.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Alan Somers <asomers@gmail.com>

MFC r306424: MFV r306422:
7254 ztest failed assertion in ztest_dataset_dirobj_verify: dirobjs + 1 == usedobjs

dsl_dataset_space is looking at the ds_bp's fill count while
dmu_objset_write_ready() is concurrently modifying it. This fix adds an
rrwlock to protect the ds_bp.

Closes #180

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Steve Gonczi <steve.gonczi@delphix.com>
Author: Paul Dagnelie <pcd@delphix.com>

MFC r305323: MFV r302991: 6950 ARC should cache compressed data

illumos/illumos-gate@dcbf3bd6a1f1360fc1afcee9e22c6dcff7844bf2
https://github.com/illumos/illumos-gate/commit/dcbf3bd6a1f1360fc1afcee9e22c6dcff7844bf2

https://www.illumos.org/issues/6950
When reading compressed data from disk, the ARC should keep the compressed
block cached and only decompress it when consumers access the block. The
uncompressed data should be short-lived allowing the ARC to cache a much larger
amount of data. The DMU would also maintain a smaller cache of uncompressed
blocks to minimize the impact of decompressing frequently accessed blocks.

Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Don Brady <don.brady@intel.com>
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: George Wilson <george.wilson@delphix.com>

MFC r305209: MFV r302660: 6314 buffer overflow in dsl_dataset_name

illumos/illumos-gate@9adfa60d484ce2435f5af77cc99dcd4e692b6660
https://github.com/illumos/illumos-gate/commit/9adfa60d484ce2435f5af77cc99dcd4e6
92b6660

https://www.illumos.org/issues/6314
Callers of dsl_dataset_name pass a buffer of size ZFS_MAXNAMELEN, but
dsl_dataset_name copies the datasets' name PLUS the snapshot name to it,
resulting in a max of 2 * ZFS_MAXNAMELEN + '@'.

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Author: Matthew Ahrens <mahrens@delphix.com>

MFC r302840: 6878 Add scrub completion info to "zpool history"