- To avoid a use-after-free, zfsvfs->z_log needs to be loaded after the
teardown lock is acquired with ZFS_ENTER().
- Avoid leaking vnode locks in zfs_rename_relock() and zfs_rename_()
when the ZFS_ENTER() macros forces an early return.
Refactor the rename implementation so that ZFS_ENTER() can be used
safely. As a bonus, this lets us use the ZFS_VERIFY_ZP() macro instead
of open-coding its implementation.
Reported-by: Peter Holm <pho@FreeBSD.org>
Tested-by: Peter Holm <pho@FreeBSD.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Sponsored-by: The FreeBSD Foundation
Closes#12717
We have to hold the teardown lock while dereferencing zfsvfs->z_os and,
I believe, when committing to the ZIL.
Note that jumping to the "out" label, "error" is always non-zero.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#12704
The objset object is reallocated during certain dataset operations, such
as rollbacks, so the objset pointer must be loaded after acquiring the
teardown lock.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#12704
The definition of struct blkcg_gq was moved into blk-cgroup.h, which is
a header that's been in Linux since 2015. This is used by
vdev_blkg_tryget() in module/os/linux/zfs/vdev_disk.c. Since the kernel
for CentOS 7 and similar-generation releases doesn't have this header,
its inclusion is guarded by a configure test.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#12819
This change adds a confiugre check to determine if bio_set_dev is a
helper macro or not. If not, then the attempt to override its internal
call to bio_associate_blkg(), with a macro definition to our own
version, is no longer possible, as the compiler won't use it when
compiling the new inline function replacement implemented in the header.
This change also creates a new vdev_bio_set_dev() function that performs
the same work, and also performs the work implemented in
vdev_bio_associate_blkg(), as it is the only thing calling that function
in our code. Our custom vdev_bio_associate_blkg() is now only compiled
if the bio_set_dev() is a macro in the Linux headers.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#12819
The iov_iter->type member was renamed iov_iter->iter_type. However,
while looking into this, realized that in 2018 a iov_iter_type(*iov)
accessor function was introduced. So if that is present, use it,
otherwise fall back to trying the existing behavior of directly
accessing type from iov_iter.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#12819
The return type for the submit_bio member of struct
block_device_operations was changed to no longer return a value.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#12819
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes#12049
Due to a possible lock inversion the zvol open call path on Linux
needs to be able to retry in the case where the spa_namespace_lock
cannot be acquired.
For Linux 5.12 an older kernel this was accomplished by returning
-ERESTARTSYS from zvol_open() to request that blkdev_get() drop
the bdev->bd_mutex lock, reaquire it, then call the open callback
again. However, as of the 5.13 kernel this behavior was removed.
Therefore, for 5.12 and older kernels we preserved the existing
retry logic, but for 5.13 and newer kernels we retry internally in
zvol_open(). This should always succeed except in the case where
a pool's vdev are layed on zvols, in which case it may fail. To
handle this case vdev_disk_open() has been updated to retry when
opening a device when -ERESTARTSYS is returned.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #12301Closes#12759
Instead, linux/pagemap.h offers a number of folio-specific functions to
be called instead. In this case, module/os/linux/zfs/zfs_vnops_os.c
wants to call wait_on_page_bit(pp, PG_writeback). This gets replaced
with folio_wait_bit(folio_page(pp), PG_writeback). This change modifies
the code to conditionally compile that if configure identifies th
presence of the folio_wait_bit() function.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#12800
The submit_bio() prototype has changed again. The version is 5.16
still only expects a single argument but the return type has changed
to void. Since we never used the returned value before update the
configure check to detect both single arg versions.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#12725
Making uio_impl.h the common header interface between Linux and FreeBSD
so both OS's can share a common header file. This also helps reduce code
duplication for zfs_uio_t for each OS.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#11622
In FreeBSD the struct uio was just a typedef to uio_t. In order to
extend this struct, outside of the definition for the struct uio, the
struct uio has been embedded inside of a uio_t struct.
Also renamed all the uio_* interfaces to be zfs_uio_* to make it clear
this is a ZFS interface.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#11438
The original xuio zero copy functionality has always been unused
on Linux and FreeBSD. Remove this disabled code to avoid any
confusion and improve readability.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#11124
Compiling with gcc 11.1.0 produces three new warnings.
Change the code slightly to avoid them.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes#12130Closes#12188Closes#12237
As of the Linux 5.9 kernel a fallthrough macro has been added which
should be used to anotate all intentional fallthrough paths. Once
all of the kernel code paths have been updated to use fallthrough
the -Wimplicit-fallthrough option will because the default. To
avoid warnings in the OpenZFS code base when this happens apply
the fallthrough macro.
Additional reading: https://lwn.net/Articles/794944/
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#12441
Kernel commits
332f606b32b6 ovl: enable RCU'd ->get_acl()
0cad6246621b vfs: add rcu argument to ->get_acl() callback
Added compatibility code to detect the new ->get_acl() interface
and correctly handle the case where the new rcu argument is set.
Reviewed-by: Coleman Kane <ckane@colemankane.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#12548
Since errors returned by zvol_create_minor_impl() are ignored by the
common code, it is more convenient to ignore make_dev_s() errors there.
It allows, for example, to get device created for the zvol after later
rename instead of having it further stuck in half-created state.
zvol_rename_minor() already ignores those errors.
While there, switch from MAXPHYS to maxphys in FreeBSD 13+.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#12375
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#12378
ZFS does not expect transient errors from crypto. For read they are
counted as checksum errors, while for write end up in panic. To not
panic on random low memory conditions retry ENOMEM errors in the OCF
wrapper function.
While there remove unneeded timeout and priority from msleep().
External-issue: https://reviews.freebsd.org/D30339
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#12077
Kernel 5.14 introduced a change where set_page_dirty of
struct address_space_operations is no longer implicitly set to
__set_page_dirty_buffers(), which ended up resulting in a NULL
pointer deref in the kernel when it is attempted to be called.
This change sets .set_page_dirty in the structure to
__set_page_dirty_nobuffers(), which was introduced with the
related patch set. The breaking change was introduce in commit
0af573780b0b13fceb7fabd49dc1b073cee9a507 to torvalds/linux.git.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#12427
This change adds SIGSTOP and SIGTSTP handling to the issig function;
this mirrors its behavior on Solaris. This way, long running kernel
tasks can be stopped with the appropriate signals. Note that doing
so with ctrl-z on the command line doesn't return control of the tty
to the shell, because tty handling is done separately from stopping
the process. That can be future work, if people feel that it is a
necessary addition.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Issue #810
Issue #10843Closes#11801
In Linux 5.14, blk_alloc_queue is no longer exported, and its usage
has been superseded by blk_alloc_disk, which returns a gendisk struct
from which we can still retrieve the struct request_queue* that is
needed in the one place where it is used. This also replaces the call
to alloc_disk(minors), and minors is now set via struct member
assignment.
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Coleman Kane <ckane@colemankane.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#12362Closes#12409
Callers of zfs_file_get and zfs_file_put can corrupt the reference
counts for the file structure resulting in a panic or a soft lockup.
When zfs send/recv runs, it will add a reference count to the
open file, and begin to send or recv the stream. If the file descriptor
is closed, then when dmu_recv_stream() or dmu_send() return we will
call zfs_file_put to remove the reference we placed on the file
structure. Unfortunately, because zfs_file_put() uses the file
descriptor to lookup the file structure, it may end up finding that
the file descriptor table no longer contains the file struct, thus
leaking the file structure. Or it might end up finding a file
descriptor for a different file and blindly updating its reference
counts. Other failure modes probably exists.
This change reworks the zfs_file_[get|put] interface to not rely
on the file descriptor but instead pass the zfs_file_t pointer around.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Co-authored-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: George Wilson <gwilson@delphix.com>
External-issue: DLPX-76119
Closes#12299
In zfs_znode_alloc we always hash inodes. If the
znode is unlinked, we do not need to hash it. This
fixes the problem where zfs_suspend_fs is doing zrele
(iput) in an async fashion, and zfs_resume_fs unlinked
drain processing will try to hash an inode that could
still be hashed, resulting in a panic.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alan Somers <asomers@gmail.com>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes#9741Closes#11223Closes#11648Closes#12210
VFS_QUOTACTL(9) has been updated to allow each filesystem to indicate
whether it has changed the busy state of the mount. The filesystem
may still assume that its .vfs_quotactl entrypoint is always called
with the mount busied, but only needs to unbusy the mount (and clear
*mp_busy) if it does something that actually requires the mount to be
unbusied. It no longer needs to blindly copy-paste the UFS protocol
for calling vfs_unbusy(9) for the Q_QUOTAOFF and Q_QUOTAON commands.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Jason Harmening <jason.harmening@gmail.com>
Closes#12052
In order for cppcheck to perform a proper analysis it needs to be
aware of how the sources are compiled (source files, include
paths/files, extra defines, etc). All the needed information is
available from the Makefiles and can be leveraged with a generic
cppcheck Makefile target. So let's add one.
Additional minor changes:
* Removing the cppcheck-suppressions.txt file. With cppcheck 2.3
and these changes it appears to no longer be needed. Some inline
suppressions were also removed since they appear not to be
needed. We can add them back if it turns out they're needed
for older versions of cppcheck.
* Added the ax_count_cpus m4 macro to detect at configure time how
many processors are available in order to run multiple cppcheck
jobs. This value is also now used as a replacement for nproc
when executing the kernel interface checks.
* "PHONY =" line moved in to the Rules.am file which is included
at the top of all Makefile.am's. This is just convenient becase
it allows us to use the += syntax to add phony targets.
* One upside of this integration worth mentioning is it now allows
`make cppcheck` to be run in any directory to check that subtree.
* For the moment, cppcheck is not run against the FreeBSD specific
kernel sources. The cppcheck-FreeBSD target will need to be
implemented and testing on FreeBSD to support this.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11508
Move zfs_get_data() in to platform-independent code. The only
platform-specific aspect of it is the way we release an inode
(Linux) / vnode_t (FreeBSD). I am not aware of a platform that
could be supported by ZFS that couldn't implement zfs_rele_async
itself. It's sibling zvol_get_data already is platform-independent.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Christian Schwarz <me@cschwarz.com>
Closes#10979
The zfs_holey() and zfs_access() functions can be made common
to both FreeBSD and Linux.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#11125
Other (all?) Linux filesystems seem to return -EPERM instead of -EACCESS
when trying to set FS_APPEND_FL or FS_IMMUTABLE_FL without the
CAP_LINUX_IMMUTABLE capability. This was detected by generic/545 test
in the fstest suite.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Luis Henriques <henrix@camandro.org>
Closes#11791
zhold() wraps igrab() on Linux, and igrab() may fail when the inode
is in the process of being deleted. This means zhold() must only be
called when a reference exists and therefore it cannot be deleted.
This is the case for all existing consumers so add a VERIFY and a
comment explaining this requirement.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Adam Moss <c@yotes.com>
Closes#11704
For small objects the kernel's slab implementation is very fast and
space efficient. However, as the allocation size increases to
require multiple pages performance suffers. The SPL kmem cache
allocator was designed to better handle these large allocation
sizes. Therefore, on Linux the kmem_cache_* compatibility wrappers
prefer to use the kernel's slab allocator for small objects and
the custom SPL kmem cache allocator for larger objects.
This logic was effectively disabled for all architectures using
a non-4K page size which caused all kmem caches to only use the
SPL implementation. Functionally this is fine, but the SPL code
which calculates the target number of objects per-slab does not
take in to account that __vmalloc() always returns page-aligned
memory. This can result in a massive amount of wasted space when
allocating tiny objects on a platform using large pages (64k).
To resolve this issue we set the spl_kmem_cache_slab_limit cutoff
to 16K for all architectures.
This particular change does not attempt to update the logic used
to calculate the optimal number of pages per slab. This remains
an issue which should be addressed in a future change.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#12152Closes#11429Closes#11574Closes#12150
If TX_WRITE is create on a file, and the file is later deleted and a new
directory is created on the same object id, it is possible that when
zil_commit happens, zfs_get_data will be called on the new directory.
This may result in panic as it tries to do range lock.
This patch fixes this issue by record the generation number during
zfs_log_write, so zfs_get_data can check if the object is valid.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Closes#10593Closes#11682
The additional iter advance is incorrect, as copy_from_iter() has
already done the right thing. This will result in the following
warning being printed to the console as of the 5.12 kernel.
Attempted to advance past end of bvec iter
This change should have been included with #11378 when a
similar change was made on the read side.
Suggested-by: @siebenmann
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Issue #11378Closes#12041Closes#12155
(cherry picked from commit 3f81aba766)
Signed-off-by: Jonathon Fernyhough <jonathon@m2x.dev>
Linux kernel commit 0f00b82e5413571ed225ddbccad6882d7ea60bc7 removes the
revalidate_disk() handler from struct block_device_operations. This
caused a regression, and this commit eliminates the call to it and the
assignment in the block_device_operations static handler assignment
code, when configure identifies that the kernel doesn't support that
API handler.
Reviewed-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#11967Closes#11977
(cherry picked from commit 48c7b0e444)
Signed-off-by: Jonathon Fernyhough <jonathon@m2x.dev>
Co-authored-by: Coleman Kane <ckane@colemankane.org>
Just like #12087, the set_acl signature changed with all the bolted-on
*userns parameters, which disabled set_acl usage, and caused #12076.
Turn zpl_set_acl into zpl_set_acl and zpl_set_acl_impl, and add a
new configure test for the new version.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes#12076Closes#12093
Linux changed the tmpfile() signature again in torvalds/linux@6521f89,
which in turn broke our HAVE_TMPFILE detection in configure.
Update that macro to include the new case, and change the signature of
zpl_tmpfile as appropriate.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes: #12060Closes: #12087
The BIO_MAX_PAGES macro is being retired in favor of a bio_max_segs()
function that implements the typical MIN(x,y) logic used throughout the
kernel for bounding the allocation, and also the new implementation is
intended to be signed-safe (which the former was not).
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#11765
(cherry picked from commit ffd6978ef5)
Signed-off-by: Jonathon Fernyhough <jonathon@m2x.dev>
In Linux 5.12, the filesystem API was modified to support ipmapped
mounts by adding a "struct user_namespace *" parameter to a number
functions and VFS handlers. This change adds the needed autoconf
macros to detect the new interfaces and updates the code appropriately.
This change does not add support for idmapped mounts, instead it
preserves the existing behavior by passing the initial user namespace
where needed. A subsequent commit will be required to add support
for idmapped mounted.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#11712
(cherry picked from commit e2a8296131)
Signed-off-by: Jonathon Fernyhough <jonathon@m2x.dev>
zp->z_lock is used in shared code for protecting projid and scantime.
We don't exercise these paths much if at all on FreeBSD, so have been
lucky enough not to have issues with the uninitialized locks so far.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes#12003
We have exclusive access to our zfsdev state object in this section
until it is invalidated by setting zs_minor to -1, so we can destroy
the state without taking a lock if we do the invalidation last, after
a member to ensure correct ordering.
While here, strengthen the assertions that zs_minor is valid when we
enter.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#11751
Avoids tripping on asserts when doing pool recovery.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#11739
Don't handle (incorrectly) kmem_zalloc() failure. With KM_SLEEP,
will never return NULL.
Free the data allocated for non-virtual kstats when deleting the object.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11767
Add parsing of the rewind options.
When I was upstreaming the change [1], I omitted the part where we
detect that the pool should be rewind. When the FreeBSD repo has
synced with the OpenZFS, this part of the code was removed.
[1] FreeBSD repo: 277f38abffc6a8160b5044128b5b2c620fbb970c
[2] OpenZFS repo: f2c027bd6a
External-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254152
Originally reviewed by: tsoome, allanjude
Originally reviewed by: kevans (ok from high-level overview)
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mariusz Zaborski <oshogbo@vexillium.org>
Closes#11730