The introduction of ARC multilists made L2ARC writing quite random,
depending on whether it found something to write in a randomly selected
sublist. This created inconsistent write patterns and poor utilization
of available sublists leading to uneven cache population.
This commit replaces random selection with systematic scanning across
all sublists within each burst. Fair headroom distribution ensures
even-depth traversal across all sublists until the target write size
is reached. Round-robin processing with random starting points eliminates
sequential bias while maintaining predictable write behavior.
The systematic approach provides consistent L2ARC filling patterns
and better utilization of available ARC data across all sublists.
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#18093
The final txgs are used only to clear out any remaining deferred
frees, and we cannot write new data to them. Make sure we do not
try to do so.
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Mariusz Zaborski <mariusz.zaborski@klarasystems.com>
Closes#18139
* Lock db_mtx around arc_release() in dbuf_release_bp()
While this function is called only in sync context, the same buffer
can be touched by dbuf_hold_impl() in open context, creating races.
All other accesses to arc_release() are already protected by db_mtx,
so just take it here too.
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
* Lock db_mtx in sa_byteswap()
While SA code seems protected by sa_lock, there is a back door of
dmu_objset_userquota_get_ids(), that may hold and access the dbuf
without sa_lock, relying only on db_mtx. Taking db_mtx here should
protect both the arc_release() and the data for db_buf.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18146
`zpool create` is supposed to log the command to the new pool’s history,
as a special record that never gets evicted from the ring buffer. but
when you create a pool with `zpool create -t`, no such record is ever
logged (#18102). that bug may be the cause of issues like #16408.
`zpool create -t` (83e9986f6e) and `zpool
import -t` (26b42f3f9d) are both designed
to override the on-disk zpool property `name` with an in-core
“temporary” name, but they work somewhat differently under the hood.
importing with a temporary name sets `spa->spa_import_flags |=
ZFS_IMPORT_TEMP_NAME` in ZFS_IOC_POOL_IMPORT, which tells
spa_write_cachefile() and spa_config_generate() to use the
ZPOOL_CONFIG_POOL_NAME in `spa->spa_config` instead of `spa->spa_name`.
creating with a temporary name permanently(!) sets the internal zpool
property `tname` (ZPOOL_PROP_TNAME) in the `zc->zc_nvlist_src` of
ZFS_IOC_POOL_CREATE, which tells zfs_ioc_pool_create()
(4ceb8dd6fd) and spa_create() to use that
name instead of `zc->zc_name`, then sets `spa->spa_import_flags |=
ZFS_IMPORT_TEMP_NAME` like an import.
but zfsdev_ioctl_common() fails to check for `tname` when saving the
pool name to `zfs_allow_log_key`, so when we call ZFS_IOC_LOG_HISTORY,
we call spa_open() on the wrong pool name and get ENOENT, so the logging
silently fails.
this patch fixes#18102 by checking for `tname` in zfsdev_ioctl_common()
like we do in zfs_ioc_pool_create().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: delan azabani <dazabani@igalia.com>
Closes#18118Closes#18102
Similar to BRT, DDT ZAP can be destroyed by sync context when it
becomes empty. Respectively similar to BRT introduce RW-lock to
protect open context methods from the destruction.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18115
ZFS send streams include a feature flag DMU_BACKUP_FEATURE_LARGE_BLOCKS
to indicate the presence of large blocks in the dataset. On the sending
side, this flag is included if the `-L` flag is passed to `zfs send`
and the feature is active in the dataset. On the receive side, the
stream is refused if the feature is active in the destination dataset
but the stream does not include the feature flag.
The problem is the feature is only activated when a large block is
born. If a large block has been born in the destination, but never
the source, the send can't work. This can arise when sending streams
back and forth between two datasets.
This commit fixes the problem by always activating the large blocks
feature when receiving a stream with the large block feature flag.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Austin Wise <AustinWise@gmail.com>
Closes#18105
Add a read-only dataset property, snapshots_changed_nsecs, which
exposes the nanosecond resolution version of snapshots_changed.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Wolfgang Hoschek <wolfgang.hoschek@mac.com>
Closes#17998Closes#18031
Now that it's built into the main zfs module in all cases, there's no
reason to put it in its own dir.
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#18071
Scan time limits do not need precision beyond 1ms. Switching
scn_sync_start_time and spa_sync_starttime from gethrtime() to
getlrtime() saves ~3% of CPU time during resilver scan stage.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18061
With higher throughput and lower latency of modern devices ZFS can
happily live with pretty short (fractions of a second) TXGs. But
the two decade old multi-second minimal time limits can almost stop
payload writes by extending TXGs beyond dirty data limits of ARC
ability to amortize it.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18060
This improves synthetic 1 byte write speed by ~2.5%.
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18063
There were some per I/O logging into dbgmsg in RAIDZ code, that
increased CPU load and wiped useful content out of dbgmsg, for
example during routine disk replacement process. I don't think
we need it to be that verbose.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18059
The first byte of the entry after compression is used for algorithm
and byte order flag. We should decrement when calling compression/
decompression algorithm.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18055
Unlike other ZAP consumers due to compression DDT does not know
how big entry it is reading from ZAP. Due to this it called
zap_length_uint64_by_dnode() and zap_lookup_uint64_by_dnode(),
each of which does full ZAP entry lookup.
Introduction of the combined ZAP method dramatically reduces the
CPU overhead and locks contention at DBUF layer.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18048
As was previously done for BRT, avoid holding/releasing DDT ZAP
dnodes for every access. Instead hold the dnodes during all their
life time, never releasing.
While at this, add _by_dnode() interfaces for zap_length_uint64()
and zap_count(), actively used by DDT code.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18047
Postponing entry removal from the DDT log in case of hit till later
single-threaded sync stage allows to make ddl_tree stable during
multi-threaded ZIO processing stage. It allows to drop the DDT lock
before the search instead of after, reducing the contention a lot.
Actually ddt_log_update_entry() was already handling the case of
entry present in the active log, so we only need to remove it from
flushing log, if the entry happen to be there.
My tests with parallel 4KB block writes show throughput increase
from 480MB/s (122K blocks/s) to 827MB/s (212K blocks/s), even
though still limited by the global DDT lock contention.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18044
Previous code effectively enforced that all async free ZIOs were
_issued_ within the TXG timeout. But they could take forever to
complete, especially if the required metadata were not in ARC.
This patch introduces periodic waits every 2000 ZIOs, which should
give at least somewhat reasonable TXG timings even for single HDD
pools with empty ARC. And makes them complete within half of the
TXG timeout, since we might still need time to sync DDT and BRT.
While there, change zfs_max_async_dedup_frees semantics to include
also clone and gang blocks, which are similar. Bump the default
value from set long ago to be more forgiving to block cloning
(still not having logs and benefiting from large TXGs), now that
we have better working time limits. The limit now is a possible
amount of dirty data produced by BRT updates.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18043
We've observed a number of cases when pool import stuck for many
minutes due to large async destroy trying to load DDT or BRT from
HDD pool. While proper destroy dosage is a separate problem,
lets give import process a chance to complete before that at all.
It may be not enough if there is a lot of ZIL to replay, but that
is harder to cover, since those are in separate syscalls.
Code investigation shown that we already have this mechanism used
for scrub/resilver, so this patch converts SCAN_IMPORT_WAIT_TXGS
into a tunable and applies it to async destroys also.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18033
Before parallel eviction implementation zfs_arc_evict_batch_limit
caused loop exits after evicting 10 headers. The cost of it is not
big and well motivated. Now though taskq task exit after the same
10 headers is much more expensive. To cover the context switch
overhead of taskq introduce another level of batching, controlled
by zfs_arc_evict_batches_limit tunable, used only for parallel
eviction.
My tests including 36 parallel reads with 4KB recordsize that shown
1.4GB/s (~460K blocks/s) before with heavy arc_evict_lock contention,
now show 6.5GB/s (~1.6M blocks/s) without arc_evict_lock contention.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17970
In zio_ddt_free, if a pruned dde is still in ddt, it would do nothing
and cause space leak.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Closes#17982Closes#17983
There is no need to do MSEC_TO_TICK() for each evicted ARC header.
We can do it when tunables are set, since we already have separate
internal variables for those.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17965
For each block written or freed ZFS dirties ds_dbuf of the dataset.
While dbuf_dirty() has a fast path for already dirty dbufs, it still
require taking the lock and doing some things visible in profiler.
Investigation shown ds_dbuf dirtying by dsl_dataset_block_born()
and some of dsl_dataset_block_kill() are just not needed, since
by the time they are called in sync context the ds_dbuf is already
dirtied by dsl_dataset_sync().
Tests show this reducing large file deletion time by ~3% by saving
CPU time of single-threaded part of the sync thread.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#18028
ZFS typically preserves proper LIFO ordering regarding map/unmap
operations that wrap the Linux kernel's kmap interfaces that
require such ordering, but one instance in abd_raidz_gen_iterate()
did not.
Similar issues have been fixed in the Linux kernel in the past,
see for instance CVE-2025-39899 for userfaultfd.
Reviewed-by: RageLtMan <rageltman@sempervictus>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: bspengler-oss <94915855+bspengler-oss@users.noreply.github.com>
Closes#15668Closes#18030
A deadlock occurs when snapshot expiry tasks are cancelled while holding
locks. The snapshot expiry task (snapentry_expire) spawns an umount
process and waits for it to complete. Concurrently, ARC memory pressure
triggers arc_prune which calls zfs_exit_fs(), attempting to cancel the
expiry task while holding locks. The umount process spawned by the
expiry task blocks trying to acquire locks held by arc_prune, which is
blocked waiting for the expiry task to complete. This creates a circular
dependency: expiry task waits for umount, umount waits for arc_prune,
arc_prune waits for expiry task.
Fix by adding non-blocking cancellation support to taskq_cancel_id().
The zfs_exit_fs() path calls zfsctl_snapshot_unmount_delay() to
reschedule the unmount, which needs to cancel any existing expiry task.
It now uses non-blocking cancellation to avoid waiting while holding
locks, breaking the deadlock by returning immediately when the task is
already running.
The per-entry se_taskqid_lock has been removed, with all taskqid
operations now protected by the global zfs_snapshot_lock held as
WRITER. Additionally, an se_in_umount flag prevents recursive waits when
zfsctl_destroy() is called during unmount. The taskqid is now only
cleared by the caller on successful cancellation; running tasks clear
their own taskqid upon completion.
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#17941
Before this change DDT lock was taken 4 times per written block,
and as effectively a pool-wide lock it can be highly congested.
This change introduces a new per-entry dde_io_lock, protecting some
fields during I/O ready and done stages, so that we don't need the
global lock there.
According to my write tests on 64-thread system with 4KB blocks this
significantly reduce the global lock contention, reducing CPU usage
from 100% to expected ~80%, and increasing write throughput by 10%.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17960
ddt_lookup() is a very busy code under a highly congested global
lock. Anything we can save here is very important.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17980
Even though unlike gang children it is not so critical for dedup
children to inherit parent's allocator, there is still no reason
for them to have allocation policy different from normal writes.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17961
Introduce a new vdev property `VDEV_PROP_SLOW_IO_REPORTING` that
allows users to disable notifications for slow devices.
This prevents ZED and/or ZFSD from degrading the pool due to slow
I/O.
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mariusz Zaborski <oshogbo@FreeBSD.org>
Closes 17477
Implement BRT (Block Reference Table) prefetch functionality similar
to existing DDT prefetch. This allows preloading BRT metadata into
ARC to improve performance for block cloning operations and frees
of earlier cloned blocks.
Make -t parameter optional. When omitted, prefetch all supported
metadata types (both DDT and BRT now).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17890
According to my observations, BRT ZAPs are typically compressible
3:1 for data and 2:1 for indirects. With ashift=12, typical these
days, it means increasing the block sizes to 8KB we may get most
of possible compression, reducing on-disk and in-ARC BRT footprint
in half by the cost of some compression/decompression overhead,
but without real write inflation, only some dirty data increase.
Increase to 32KB similar to DDT could further increase compression
and storage efficiency, but at the cost of write inflation and
much bigger dirty data increase, which we can not properly control
now. So lets leave this for a time when BRT log gets implemented.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17916
dmu_object_info_from_dnode() takes two locks and copies plenty of
data that we don't need in zap_lockdir_impl(). Just read dn_type
directly in this hot path.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17921
This is useful as debugging support, as it lets namespace lock
operations be traced directly. It will also be useful for future work to
reduce the use of spa_namespace_lock, traditionally a source of
difficult deadlocks.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes#17906
Free issue threads might block waiting for synchronous DDT, BRT or
GANG header reads. So unlike other taskqs using ZTI_SCALE to scale
with number of CPUs, here we also need some amount of threads to
potentially saturate pool reads. I am not sure we always want the
96 threads we had before ZTI_SCALE introduction at #11966 on small
systems, but lets make it at least 32.
While here, make free taskqs configurable, similar to read and
write ones.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17903
Change the spelling of "begining" on line 4875 to
"beginning".
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Adi Gollamudi <adigollamudi@gmail.com>
Closes#17905
When a write comes in via dmu_sync_late_arrival, its txg is equal to the
open TXG. If that write gangs, and we have not yet activated the new
gang header feature, and the gang header we pick can store a larger gang
header, we will try to schedule the upgrade for the open TXG + 1. In
debug mode, this causes an assertion to trip. This PR sets the TXG for
activating the feature to be the larger of either the current open TXG
or the syncing TXG + 1.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Closes#17824
Currently this function uses L0 offsets which:
1. is hard to read since it maps offsets to blkid and back each call
2. necessitates dnode_next_block to handle edge cases at limits
3. makes it hard to tell if the traversal can loop infinitely
Instead, update this and dnode_next_offset to work in (blkid, index).
This way the blkid manipulations are clear, and it's also clear that
the traversal always terminates since blkid goes one direction.
I've also considered updating dnode_next_offset to operate on blkid.
Callers use both patterns, so maybe another PR can split the cases?
While here tidy up dnode_next_offset_level comments.
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Robert Evans <evansr@google.com>
Closes#17792
In cases where all issued ZIOs must succeed, and we can't do
anything clever about the errors, we should just explicitly set
ZIO_FLAG_TRYHARD and let OS to do all the reasonable retries.
In other cases, where retries can be different from the original,
for example, some ZIOs are allowed to fail due to redundancy, or
we can disable aggregation on retrial to get at least some of
the data, we can do first pass without TRYHARD, and only if needed
retry with ZIO_FLAG_IO_RETRY (which implies TRYHARD semantics).
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17877
Both DDT log and BRT counters we read on pool import and then only
append or overwrite in full blocks. We don't need them in DMU or
ARC caches. Fortunately we have DMU_UNCACHEDIO for this now.
Even more we don't need BRT in non-evictable metadata DMU caches,
since it will likely never fit there, while block the cache from
its original users. Since DMU_OT_IS_METADATA_CACHED() has no way
to differentiate the new metadata types, mark BRT with storage
type of DMU_OT_DDT_ZAP. As side effect it will also put it on
dedup device, but that should actually be right.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17875
Since we set bv_mos_brtvdev block size, and since we keep dirty
bitmap at the same granularity, we should keep the allocations
and writes done with. Otherwise it makes the last block write
short, that will be odd once we implement writing of only dirty
blocks, but also requires read-modify-write on DMU layer.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17875
Over the time many of DMU functions got flags argument to control
prefetch, caching, etc. Few functions though left without it, even
though closer look shown that many of them do not require prefetch
due to their access pattern. This patch adds the flags argument to
dmu_write(), dmu_buf_hold_array() and dmu_buf_hold_array_by_bonus(),
passing DMU_READ_NO_PREFETCH where applicable.
I am going to also pass DMU_UNCACHEDIO to some of them later.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17872
We must return -1 instead of ENOENT if the special zvol threading
property set function can't locate the dataset (this would typically
happen with an encypted and unmounted zvol) so that the operation
gets inserted properly into the nvlist for operations to set. This
is because we want the property to be set once the zvol is
decrypted again.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Andrew Walker <awalker@ixsystems.com>
Closes#17836
Make a minor update to the 'zpool remove' man page to clarify both
raidz and draid pools do not support removal, and change sector to
ashift which is what we actually care about.
Update the big theory comment in vdev_removal.c to accurately reflect
which types of vdevs can be removed. Furthermore, I've added some
discussion for the casual reader to briefly explain the top-level
vdev removal restrictions. This has been a common area of confusion
and it's not intuitive where they come from without understanding
the implementation details.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17847
It's an hrtime_t, which is an unsigned long long. In practice this is
just a U64.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Rob Norris <rob.norris@klarasystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#17833
Otherwise the compiler warns about it on production FreeBSD builds.
The routine proved resilient to attempts to ifdef on debug.
Sponsored by: Rubicon Communications, LLC ("Netgate")
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#17818
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Igor Ostapenko <igor.ostapenko@klarasystems.com>
Closes#17793
Originally this was created for MMP, but now new cases are emerging
where the same mechanism is required. Hence the name's generalization.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Igor Ostapenko <igor.ostapenko@klarasystems.com>
Closes#17793
