It was broken for several reasons:
* VOP_UNLOCK lost an argument in 13.0. So OpenZFS should be using
VOP_UNLOCK1, but a few direct calls to VOP_UNLOCK snuck in.
* The location of the zlib header moved in 13.0 and 12.1. We can drop
support for building on 12.0, which is EoL.
* knlist_init lost an argument in 13.0. OpenZFS change 9d0887402b
assumed 13.0 or later.
* FreeBSD 13.0 added copy_file_range, and OpenZFS change 67a1b03791
assumed 13.0 or later.
Sponsored-by: Axcient
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#15551
Variable 'uma_align_cache' has not been used since commit "FreeBSD: Use
a hash table for taskqid lookups" (3933305ea). Moreover, it is soon
going to become private to FreeBSD's UMA in 15.0-CURRENT (main),
14.0-STABLE (stable/14) and 13.2-STABLE (stable/13). Should accessing
this information become necessary again, one will have to use the new
accessors for recent versions.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olivier Certner <olce.freebsd@certner.fr>
Closes#15416
- Group tqent_task and tqent_timeout_task into a union. They are
never used same time. This shrinks taskq_ent_t from 192 to 160 bytes.
- Remove tqent_registered. Use tqent_id != 0 instead.
- Remove tqent_cancelled. Use taskqueue pending counter instead.
- Change tqent_type into uint_t. We don't need to pack it any more.
- Change tqent_rc into uint_t, matching refcount(9).
- Take shared locks in taskq_lookup().
- Call proper taskqueue_drain_timeout() for TIMEOUT_TASK in
taskq_cancel_id() and taskq_wait_id().
- Switch from CK_LIST to regular LIST.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#15356
After addressing coverity complaints involving `nvpair_name()`, the
compiler started complaining about dropping const. This lead to a rabbit
hole where not only `nvpair_name()` needed to be constified, but also
`nvpair_value_string()`, `fnvpair_value_string()` and a few other static
functions, plus variable pointers throughout the code. The result became
a fairly big change, so it has been split out into its own patch.
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#14612
We had three sha2.h headers in different places.
The FreeBSD version, the Linux version and the generic solaris version.
The only assembly used for acceleration was some old x86-64 openssl
implementation for sha256 within the icp module.
For FreeBSD the whole SHA2 files of FreeBSD were copied into OpenZFS,
these files got removed also.
Tested-by: Rich Ercolani <rincebrain@gmail.com>
Tested-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes#13741
The Linux 5.16.14 kernel's coccicheck caught this. The semantic
patch that caught it was:
./scripts/coccinelle/null/badzero.cocci
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#14372
The Linux 5.16.14 kernel's coccicheck caught these. The semantic patch
that caught them was:
./scripts/coccinelle/api/alloc/alloc_cast.cocci
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#14372
When inside a jail, visibility on datasets not "jailed" to the
jail is restricted. However, it was possible to enumerate all
datasets in the pool by looking at the kstats sysctl MIB.
Only the kstats corresponding to datasets that the user has
visibility on are accessible now.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#14254
Rather than doing a terrible credential swapping hack, we just
check that the thing being mounted is a snapshot, and the mountpoint
is the zfsctl directory, then we allow it.
If the mount attempt is from inside a jail, on an unjailed dataset
(mounted from the host, not by the jail), the ability to mount the
snapshot is controlled by a new per-jail parameter: zfs.mount_snapshot
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Sponsored-by: Modirum MDPay
Sponsored-by: Klara Inc.
Closes#13758
Avoid assuming that a pointer can fit in a uint64_t and use uintptr_t
instead.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Signed-off-by: Brooks Davis <brooks.davis@sri.com>
Closes#14131
`snprintf()` is meant to protect against buffer overflows, but operating
on the buffer using its return value, possibly by calling it again, can
cause a buffer overflow, because it will return how many characters it
would have written if it had enough space even when it did not. In a
number of places, we repeatedly call snprintf() by successively
incrementing a buffer offset and decrementing a buffer length, by its
return value. This is a potentially unsafe usage of `snprintf()`
whenever the buffer length is reached. CodeQL complained about this.
To fix this, we introduce `kmem_scnprintf()`, which will return 0 when
the buffer is zero or the number of written characters, minus 1 to
exclude the NULL character, when the buffer was too small. In all other
cases, it behaves like snprintf(). The name is inspired by the Linux and
XNU kernels' `scnprintf()`. The implementation was written before I
thought to look at `scnprintf()` and had a good name for it, but it
turned out to have identical semantics to the Linux kernel version.
That lead to the name, `kmem_scnprintf()`.
CodeQL only catches this issue in loops, so repeated use of snprintf()
outside of a loop was not caught. As a result, a thorough audit of the
codebase was done to examine all instances of `snprintf()` usage for
potential problems and a few were caught. Fixes for them are included in
this patch.
Unfortunately, ZED is one of the places where `snprintf()` is
potentially used incorrectly. Since using `kmem_scnprintf()` in it would
require changing how it is linked, we modify its usage to make it safe,
no matter what buffer length is used. In addition, there was a bug in
the use of the return value where the NULL format character was not
being written by pwrite(). That has been fixed.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#14098
Both Clang's Static Analyzer and Synopsys' Coverity would ignore
assertions. Following Clang's advice, we annotate our assertions:
https://clang-analyzer.llvm.org/annotations.html#custom_assertions
This makes both Clang's Static Analyzer and Coverity properly identify
assertions. This change reduced Clang's reported defects from 246 to
180. It also reduced the false positives reported by Coverityi by 10,
while enabling Coverity to find 9 more defects that previously were
false negatives.
A couple examples of this would be CID-1524417 and CID-1524423. After
submitting a build to coverity with the modified assertions, CID-1524417
disappeared while the report for CID-1524423 no longer claimed that the
assertion tripped.
Coincidentally, it turns out that it is possible to more accurately
annotate our headers than the Coverity modelling file permits in the
case of format strings. Since we can do that and this patch annotates
headers whenever `__coverity_panic__()` would have been used in the
model file, we drop all models that use `__coverity_panic__()` from the
model file.
Upon seeing the success in eliminating false positives involving
assertions, it occurred to me that we could also modify our headers to
eliminate coverity's false positives involving byte swaps. We now have
coverity specific byteswap macros, that do nothing, to disable
Coverity's false positives when we do byte swaps. This allowed us to
also drop the byteswap definitions from the model file.
Lastly, a model file update has been done beyond the mentioned
deletions:
* The definitions of `umem_alloc_aligned()`, `umem_alloc()` andi
`umem_zalloc()` were originally implemented in a way that was
intended to inform coverity that when KM_SLEEP has been passed these
functions, they do not return NULL. A small error in how this was
done was found, so we correct it.
* Definitions for umem_cache_alloc() and umem_cache_free() have been
added.
In practice, no false positives were avoided by making these changes,
but in the interest of correctness from future coverity builds, we make
them anyway.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13902
Coverity found a bug in `zfs_secpolicy_create_clone()` where it is
possible for us to pass an unterminated string when `zfs_get_parent()`
returns an error. Upon inspection, it is clear that using `strlcpy()`
would have avoided this issue.
Looking at the codebase, there are a number of other uses of `strncpy()`
that are unsafe and even when it is used safely, switching to
`strlcpy()` would make the code more readable. Therefore, we switch all
instances where we use `strncpy()` to use `strlcpy()`.
Unfortunately, we do not portably have access to `strlcpy()` in
tests/zfs-tests/cmd/zfs_diff-socket.c because it does not link to
libspl. Modifying the appropriate Makefile.am to try to link to it
resulted in an error from the naming choice used in the file. Trying to
disable the check on the file did not work on FreeBSD because Clang
ignores `#undef` when a definition is provided by `-Dstrncpy(...)=...`.
We workaround that by explictly including the C file from libspl into
the test. This makes things build correctly everywhere.
We add a deprecation warning to `config/Rules.am` and suppress it on the
remaining `strncpy()` usage. `strlcpy()` is not portably avaliable in
tests/zfs-tests/cmd/zfs_diff-socket.c, so we use `snprintf()` there as a
substitute.
This patch does not tackle the related problem of `strcpy()`, which is
even less safe. Thankfully, a quick inspection found that it is used far
more correctly than strncpy() was used. A quick inspection did not find
any problems with `strcpy()` usage outside of zhack, but it should be
said that I only checked around 90% of them.
Lastly, some of the fields in kstat_t varied in size by 1 depending on
whether they were in userspace or in the kernel. The origin of this
discrepancy appears to be 04a479f706 where
it was made for no apparent reason. It conflicts with the comment on
KSTAT_STRLEN, so we shrink the kernel field sizes to match the userspace
field sizes.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13876
At shutdown time, we drain all of the zevents and set the
ZEVENT_SHUTDOWN flag. On FreeBSD, we may end up calling
zfs_zevent_destroy() after the zevent_lock has been destroyed while
the sysevent thread is winding down; we observe ESHUTDOWN, then back
out.
Events have already been drained, so just inline the kmem_free call in
sysevent_worker() to avoid the race, and document the assumption that
zfs_zevent_destroy doesn't do anything else useful at that point.
This fixes a panic that can occur at module unload time.
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
Closes#13220
bcopy() has a confusing argument order and is actually a move, not a
copy; they're all deprecated since POSIX.1-2001 and removed in -2008,
and we shim them out to mem*() on Linux anyway
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes#12996
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes#12771
When mounting a snapshot in the .zfs/snapshots control directory,
temporarily assume roots credentials to perform the VFS_MOUNT().
This allows regular users and users inside jails to access these
snapshots.
The regular usermount code is not helpful here, since it requires
that the user performing the mount own the mountpoint, which won't
be the case for .zfs/snapshot/<snapname>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Sponsored-By: Modirum MDPay
Sponsored-By: Klara Inc.
Closes#11312
This mostly reverts "3537 want pool io kstats" commit of 8 years ago.
From one side this code using pool-wide locks became pretty bad for
performance, creating significant lock contention in I/O pipeline.
From another, there are more efficient ways now to obtain detailed
statistics, while this statistics is illumos-specific and much less
usable on Linux and FreeBSD, reported only via procfs/sysctls.
This commit does not remove KSTAT_TYPE_IO implementation, that may
be removed later together with already unused KSTAT_TYPE_INTR and
KSTAT_TYPE_TIMER.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#12212
Convert use of ASSERT() to ASSERT0(), ASSERT3U(), ASSERT3S(),
ASSERT3P(), and likewise for VERIFY(). In some cases it ended up
making more sense to change the code, such as VERIFY on nvlist
operations that I have converted to use fnvlist instead. In one
place I changed an internal struct member from int to boolean_t to
match its use. Some asserts that combined multiple checks with &&
in a single assert have been split to separate asserts, to make it
apparent which check fails.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11971
IS_XATTRDIR is never used.
v_count is only used in two places, one immediately followed by the
use of the real name, v_usecount.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes#11973
This obeys the change in freebsd/freebsd-src@bce7ee9d4
External-issue: https://reviews.freebsd.org/D26980
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Martin Matuska <mm@FreeBSD.org>
Closes#11947
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
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
Set VIRF_MOUNTPOINT flag on snapshot mountpoint.
Authored-by: Mateusz Guzik <mjg@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11458
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
These kstats are often expensive to compute so we want to avoid them
unless specifically requested.
The following kstats are affected by this change:
kstat.zfs.${pool}.multihost
kstat.zfs.${pool}.misc.state
kstat.zfs.${pool}.txgs
kstat.zfs.misc.fletcher_4_bench
kstat.zfs.misc.vdev_raidz_bench
kstat.zfs.misc.dbufs
kstat.zfs.misc.dbgmsg
In FreeBSD 13, sysctl(8) has been updated to still list the
names/description/type of skipped sysctls so they are still
discoverable.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11099
The zfs_fsync, zfs_read, and zfs_write function are almost identical
between Linux and FreeBSD. With a little refactoring they can be
moved to the common code which is what is done by this commit.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#11078
The 32-bit counter eventually wraps to 0 which is a sentinel for invalid
id.
Make it 64-bit on LP64 platforms and 0-check otherwise.
Note: Linux counterpart uses id stored per queue instead of a global.
I did not check going that way is feasible with the goal being the
minimal fix doing the job.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#11059
In FreeBSD, there are three compile environments that are supported:
user land, the kernel and the bootloader / standalone. Adjust the
headers to compile in the standalone environment. Limit kernel-only
items from view when _STANDALONE is defined.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Warner Losh <imp@FreeBSD.org>
Closes#10998
With procfs_list kstats implemented for FreeBSD, dbufs are now exposed
as kstat.zfs.misc.dbufs.
On FreeBSD, dbufstats can use the sysctl instead of procfs when no
input file has been given.
Enable the dbufstats tests on FreeBSD.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#11008
We were missing an include for kernel FPU functions, breaking the build
on FreeBSD 12.1-RELEASE. This was apparently being pulled in from
elsewhere on stable/12 and head.
Sorted the other includes in these files while here.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11005
The procfs_list interface is required by several kstats. Implement
this functionality for FreeBSD to provide access to these kstats.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10890
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10899
Without this, the sysctl system calls will acquire a global lock before
invoking the handler. This is noticeable in some situations when
running top(1). The global lock is mostly vestigal but continues to see
some use and so contention is still a problem; until the default sense
of the MPSAFE flag changes, we have to annotate each and every handler.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#10836
This is in preparation for some functional changes.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#10950
Added comments in following files
with links to Illumos manual pages:
./module/avl/avl.c
./module/nvpair/nvpair.c
./module/os/linux/spl/spl-kstat.c
./module/os/freebsd/spl/spl_kstat.c
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Spencer Kinny <spencerkinny1995@gmail.com>
Closes#5113Closes#10859
Moving spa_stats added the additional burden of supporting
KSTAT_TYPE_IO.
spa_state_addr will always return a valid value regardless of
the value of 'n'. On FreeBSD this will cause an infinite loop
as it relies on the raw ops addr routine to indicate that there
is no more data.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10860
FreeBSD's previous ZFS implemented INGLOBALZONE(thread) as
(!jailed((thread)->td_ucred)) and passed curthread to INGLOBALZONE.
We pass curproc instead of curthread, so we can achieve the same effect
with (!jailed((proc)->p_ucred)). The implementation is trivial enough
to fit on a single line in a define. We don't really need a whole
separate function for something that's already macros all the way down.
Eliminate in_globalzone.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#10851
A few kstats use KSTAT_TYPE_RAW to provide a string generated on
demand. Implementing these as sysctls was punted until now.
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10836
The #pragma ident is a historical relic and not needed any more, this
pragma is actually unknown for common compilers and is only causing
trouble.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Toomas Soome <tsoome@me.com>
Closes#10810
Stepping stone toward re-enabling spa_thread on FreeBSD.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10715
Remove dead code to make the implementation easier to understand.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes#10650
A collection of header changes to enable FreeBSD to build
with vendored OpenZFS.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10635
Renamed to avoid conflicting with refcount.h when a different
implementation is already provided by the platform.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10620