Following the fix for 9018 (Replace kmem_cache_reap_now() with
kmem_cache_reap_soon), the arc_reclaim_thread() no longer blocks
while reaping. However, the code is still confusing and error-prone,
because this thread has two responsibilities. We should instead
separate this into two threads each with their own responsibility:
1. keep `arc_size` under `arc_c`, by calling `arc_adjust()`, which
improves `arc_is_overflowing()`
2. keep enough free memory in the system, by calling
`arc_kmem_reap_now()` plus `arc_shrink()`, which improves
`arc_available_memory()`.
Furthermore, we can use the zthr infrastructure to separate the
"should we do something" from "do it" parts of the logic, and
normalize the start up / shut down of the threads.
Authored by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Dan McDonald <danmcd@joyent.com>
Reviewed by: Tim Kordas <tim.kordas@joyent.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Brad Lewis <brad.lewis@delphix.com>
Signed-off-by: Brad Lewis <brad.lewis@delphix.com>
OpenZFS-issue: https://www.illumos.org/issues/9284
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/de753e34f9Closes#8165
Linux kstat IO and TIMER printed values as signed. However the counters
only increment. Thus humans looking at the data can be confused when
the counters roll over.
Note: The recommended use of these values is to monitor the derivative,
which don't really care about the sign. See explanations related to
non-negative derivatives in the various time-series databases.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <guss80@gmail.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Richard Elling <Richard.Elling@RichardElling.com>
Closes#8131Closes#8198
The existing mechanisms for determining what code is running in the
kernel do not always correctly report the git hash. The versions
reported there do not reflect changes made since `configure` was run
(i.e. incremental builds do not update the version) and they are
misleading if git tags are not set up properly. This applies to
`modinfo zfs`, `dmesg`, and `/sys/module/zfs/version`.
There are complicated requirements on how the existing version is
generated. Therefore we are leaving that alone, and adding a new
mechanism to record and retrieve the git hash:
`cat /proc/sys/kernel/spl/gitrev`
The gitrev is re-generated at compile time, when running `make`
(including for incremental builds). The value is the output of `git
describe` (or "unknown" if not in a git repo or there are uncommitted
changes).
We're also removing /proc/sys/kernel/spl/version, which was never very
useful.
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Tim Chase <tim@chase2k.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#7931Closes#7965
There are some issues with the way the seq_file interface is implemented
for kstats backed by linked lists (zfs_dbgmsgs and certain per-pool
debugging info):
* We don't account for the fact that seq_file sometimes visits a node
multiple times, which results in missing messages when read through
procfs.
* We don't keep separate state for each reader of a file, so concurrent
readers will receive incorrect results.
* We don't account for the fact that entries may have been removed from
the list between read syscalls, so reading from these files in procfs
can cause the system to crash.
This change fixes these issues and adds procfs_list, a wrapper around a
linked list which abstracts away the details of implementing the
seq_file interface for a list and exposing the contents of the list
through procfs.
Reviewed by: Don Brady <don.brady@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: John Gallagher <john.gallagher@delphix.com>
External-issue: LX-1211
Closes#7819
The RT rwsem implementation was changed to allow multiple readers
as of the 4.9.20-rt16 patch set. This results in a build failure
because the existing implementation was forced to directly access
the rwsem structure which has changed.
While this could be accommodated by adding additional compatibility
code. This patch resolves the build issue by simply assuming the
rwsem can never be upgraded. This functionality is a performance
optimization and all callers must already handle this case.
Converting the last remaining use of __SPIN_LOCK_UNLOCKED to
spin_lock_init() was additionally required to get a clean build.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#7589
1. Add a proc entry to display the pool's state:
$ cat /proc/spl/kstat/zfs/tank/state
ONLINE
This is done without using the spa config locks, so it will
never hang.
2. Fix 'zpool status' and 'zpool list -o health' output to print
"SUSPENDED" instead of "ONLINE" for suspended pools.
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#7331Closes#7563
Minimal changes required to integrate the SPL sources in to the
ZFS repository build infrastructure and packaging.
Build system and packaging:
* Renamed SPL_* autoconf m4 macros to ZFS_*.
* Removed redundant SPL_* autoconf m4 macros.
* Updated the RPM spec files to remove SPL package dependency.
* The zfs package obsoletes the spl package, and the zfs-kmod
package obsoletes the spl-kmod package.
* The zfs-kmod-devel* packages were updated to add compatibility
symlinks under /usr/src/spl-x.y.z until all dependent packages
can be updated. They will be removed in a future release.
* Updated copy-builtin script for in-kernel builds.
* Updated DKMS package to include the spl.ko.
* Updated stale AUTHORS file to include all contributors.
* Updated stale COPYRIGHT and included the SPL as an exception.
* Renamed README.markdown to README.md
* Renamed OPENSOLARIS.LICENSE to LICENSE.
* Renamed DISCLAIMER to NOTICE.
Required code changes:
* Removed redundant HAVE_SPL macro.
* Removed _BOOT from nvpairs since it doesn't apply for Linux.
* Initial header cleanup (removal of empty headers, refactoring).
* Remove SPL repository clone/build from zimport.sh.
* Use of DEFINE_RATELIMIT_STATE and DEFINE_SPINLOCK removed due
to build issues when forcing C99 compilation.
* Replaced legacy ACCESS_ONCE with READ_ONCE.
* Include needed headers for `current` and `EXPORT_SYMBOL`.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
TEST_ZIMPORT_SKIP="yes"
Closes#7556
This commit removes everything from the repository except the core
SPL implementation for Linux. Those files which remain have been
moved to non-conflicting locations to facilitate the merge.
The README.md and associated files have been updated accordingly.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This patch contains no functional changes. It is solely intended
to resolve cstyle warnings in order to facilitate moving the spl
source code in to the zfs repository.
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#687
vn_init() and vn_fini() had been renamed by 12ff95ff in 2011.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@osnexus.com>
Closes#686
This is only used via ->ks_update of `kstat_t *`.
This isn't exported nor do headers have its prototype.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@osnexus.com>
Closes#686
This patch contains no functional changes. It is solely intended
to resolve cstyle warnings in order to facilitate moving the spl
source code in to the zfs repository.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#681
Add missing helper function cv_timedwait_io(), it should be used
when waiting on IO with a specified timeout.
Reviewed-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#674
Use timer_setup() macro and new timeout function definition.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#670Closes#671
The kernel_read & kernel_write functions have always wrapped the
vfs_read & vfs_write functions respectively. However, they could
not be used by vn_rdwr() since the offset wasn't passed as a
pointer. This prevented us from being able to properly update
the file offset.
Linux 4.14 unexported vfs_read & vfs_write but also changed the
signature of kernel_read & kernel_write to provide the needed
functionality. Use these updated functions when available.
Reviewed-by: Pritam Baral <pritam@pritambaral.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#656Closes#667
On systems with CONFIG_SMP turned off, spin_is_locked always returns
false causing these assertions to fail. Remove them as suggested in
zfsonlinux/zfs#6558.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: James Cowgill <james.cowgill@mips.com>
Closes#665
Both vn_rename and vn_remove have been historically problematic
to implement reliably. Rather than fixing them yet again they
are being removed.
Reviewed-by: Arkadiusz Bubala <arkadiusz.bubala@open-e.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#648Closes#661
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Elling <Richard.Elling@RichardElling.com>
Closes#652Closes#651
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: gaurkuma <gauravk.18@gmail.com>
Closes#641
This was probably accidentally committed in
aeb9baa618
Fix: handle NULL case in spl_kmem_free_track()
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Closes#644
taskq work item to more than one queue concurrently. Also, please
see discussion in zfsonlinux/zfs#3840.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Closes#609
taskq_seq_show_impl walks the tq_active_list to show the tqent_func and
tqent_arg. However for taskq_dispatch_ent, it's very likely that the
task entry will be freed during the function call, and causes a
use-after-free bug.
To fix this, we duplicate the task entry to an on-stack struct, and
assign it instead to tqt_task. This way, the tq_lock alone will
guarantee its safety.
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#638Closes#640
gcc-7 seems to use __udivmoddi4 for 64-bit division on 32-bit arch. This
patch implement them so we don't get undefined reference error.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes zfsonlinux/zfs#6417
Closes#636
In unattended operations it's often more useful to have node
panic and reboot when it encounters problems as opposed to
sit there indefinitely waiting for somebody to discover it.
This implements an spl_panic_crash module parameter, set it
to nonzero to cause spl_panic() to call panic().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Closes#634
When we load a ZFS pool having spa_name equals to some existing kstat
we would have to create a duplicate entry, which procfs doesn't like.
For instance a ZFS pool named "zil" would have its kstat "txgs"
(module "zfs/zil") intalled under "/proc/spl/kstat/zfs/zil":
unfortunately we already have a kstat named "zil" (module "zfs")
installed in the same procfs location.
Avoid this issue by skipping the duplicate entry creation in procfs.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#628
Historically the SPL cached the system hostid the first time it
was accessed. This was done to speed up subsequent accesses.
But in practice the system host id is rarely accessed and its
inconvenient that it doesn't promptly detect /etc/hostid
configuration changes. Therefore, zone_get_hostid() has been
updated to always refresh the system hostid reported.
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#626
Perform the already past expiration time check before updating
cvp->cv_mutex with the provided mutex. This check only depends
on local state. Doing it first ensures that cvp->cv_mutex will not
be updated in the timeout case or if it's ever called with an
expire_time <= now.
Reviewed-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#616
Change SPL_FSTRANS to optionally contains PF_FSTRANS. Also, add
__spl_pf_fstrans_check for the checks specifically for PF_FSTRANS.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#614
Before kernel 2.6.29 credentials were embedded in task_structs, and zfs had
cases where one thread would need to refer to the credential of another thread,
forcing it to take a hold on the foreign thread's task_struct to ensure it was
not freed.
Since 2.6.29, the credential has been moved out of the task_struct into a
cred_t.
In addition, the mainline kernel originally did not export __put_task_struct()
but the RHEL5 kernel did, according to zfsonlinux/spl@e811949a57. As of
2.6.39 the mainline kernel exports it.
There is no longer zfs code that takes or releases holds on a task_struct, and
so there is no longer any reference to __put_task_struct().
This affects the linux 4.11 kernel because the prototype for
__put_task_struct() is in a new include file (linux/sched/task.h) and so the
config check failed to detect the exported symbol.
Removing the unnecessary stub and corresponding config check. This works on
kernels since the oldest one currently supported, 2.6.32 as shipped with
Centos/RHEL.
Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes#608
There are changes to vfs_getattr() in torvalds/linux@a528d35. The new
interface is:
int vfs_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
The request_mask argument indicates which field(s) the caller intends to
use. Fields the caller does not specify via request_mask may be set in
the returned struct anyway, but their values may be approximate.
The query_flags argument indicates whether the filesystem must update
the attributes from the backing store.
This patch uses the query_flags which result in vfs_getattr behaving the same
as it did with the 2-argument version which the kernel provided before
Linux 4.11.
Members blksize and blocks are now always the same size regardless of
arch. They match the size of the equivalent members in vnode_t.
The configure checks are modified to ensure that the appropriate
vfs_getattr() interface is used.
A more complete fix, removing the ZFS dependency on vfs_getattr()
entirely, is deferred as it is a much larger project.
Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes#608
Replace uses of set_task_state(current, STATE) with
set_current_state(STATE).
In Linux 4.11, torvalds/linux@642fa44, set_task_state() is removed.
All spl uses are of the form set_task_state(current, STATE).
set_current_state(STATE) is equivalent and has been available since
Linux 2.2.26.
Furthermore, set_current_state(STATE) is already used in about 15
locations within spl. This change should have no impact other than
removing an unnecessary dependency.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes#603
Resolve a false positive in the kmemleak checker by shifting to the
kernel slab. It shows up because vn_file_cache is using KMC_KMEM
which is directly allocated using __get_free_pages, which is not
automatically tracked by kmemleak.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#599
SLAB_USERCOPY flag was used to indicate PAX
not to kill copies from kernel to userland.
With recent grsecurity patchset and
CONFIG_GRKERNSEC_HIDESYM that enables
CONFIG_PAX_USERCOPY zfs would panic.
Handle newer API while keeping old one functional.
Tested-by: RageLtMan <rageltman@sempervictus>
Reviewed-by: spendergrsec <spender@grsecurity.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Kevin Tanguy <kevin.tanguy@ovh.net>
Closes#595
When building SPL within the kernel tree, C99 initializers cause
build failures and need to be converted to C89 as kernel CFLAGS
specify -std=gnu89.
This fix was provided by @behlendorf in #595 discussion notes and
manually implemented in the current master revision.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: RageLtMan <rageltman@sempervictus>
Closes#597
The main complication from the RT patch set is that the RW semaphore
locks change such that read locks on an rwsem can be taken only by
a single thread. All other threads are locked out. This single
thread can take a read lock multiple times though. The underlying
implementation changes to a mutex with an additional read_depth
count.
The implementation can be best understood by inspecting the RT
patch. rwsem_rt.h and rt.c give the best insight into how RT
rwsem works. My implementation for rwsem_tryupgrade is basically
an inversion of rt_downgrade_write found in rt.c. Please see the
comments in the code.
Unfortunately, I have to drop SPLAT rwlock test4 completely as this
test tries to take multiple locks from different threads, which RT
rwsems do not support. Otherwise SPLAT, zconfig.sh, zpios-sanity.sh
and zfs-tests.sh pass on my Debian-testing VM with the kernel
linux-image-4.8.0-1-rt-amd64.
Tested-by: kernelOfTruth <kerneloftruth@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Clemens Fruhwirth <clemens@endorphin.org>
Closes zfsonlinux/zfs#5491
Closes#589Closes#308
Add a dedicated system_delay_taskq for long delay like spa_deadman and
zpl_posix_acl_free. This will allow us to use system_taskq in the manner of
dispatch multiple tasks and call taskq_wait_outstanding.
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#588
To prevent holding tq_lock for too long.
Before zfsonlinux/zfs@8e71ab9, hogging delay tasks and cat /proc/spl/taskq
would easily cause a lockup. While that bug has been fixed. It's probably
still a good idea to do this just in case task lists grow too large.
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#586
Add the TASKQID_INVALID and TASKQID_INITIAL macros and update the
taskq implementation and test cases to use them. This is solely
for the purposes of readability and introduces no functional change.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Add a minimal implementation of vmem_size() which accounts for the
virtual memory usage of the SPL's kmem cache. This functionality
is only useful on 32-bit systems with a small virtual address space.
The following assumptions are made:
1) The major SPL consumer of virtual memory is the kmem cache.
2) Memory allocated with vmem_alloc() is short lived and can be ignored.
3) Allow a 4MB floor as a generous pad given normal consumption.
4) The spl_kmem_cache_sem only contends with cache create/destroy.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
In Linux 4.9, torvalds/linux@81243ea, group_info changed from 2d array via
->blocks to 1d array via ->gid. We change the spl cred functions accordingly.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#581
init_groups has 0 nblocks, therefore calling the current crgetgroups with
init_groups would result in out-of-bound access. We fix this by returning NULL
when nblocks is 0.
Cap crgetngroups to NGROUPS_PER_BLOCK, since crgetgroups will only return
blocks[0].
Also, remove all get_group_info. The cred already holds reference on the
group_info, and cred is not mutable. So there's no reason to hold extra
reference, if we hold cred.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#556
When iterating per_cpu values, we need to use for_each_possible_cpu. While
NR_CPUS indicates the number of CPU supported by the kernel, it might not
initialize all of them if the kernel decides it's not possible to use them.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#578
Due to changes in the task_struct the following warning is occurs
when initializing the global p0. Since this structure only exists
for it's address to be taken initialize it in a manor which isn't
sensitive to internal changes to the structure.
module/spl/spl-generic.c:58:1: error: missing braces around
initializer [-Werror=missing-braces]
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#576
In order to support ABD with large blocks the spl_kmem_alloc_warn
limit needs to be increased to 64K.
A 16M block requires that pointers be stored for 4096 4K-pages
on an x86_64 system. Each of these pointers is 8 bytes requiring
an allocation of 8*4096=32,768 bytes. The addition of a small
header to this structure pushes the allocation over the default
32K warning threshold.
In addition, fix a small bug where MAX was used instead of MIN
when setting the default. This ensures a reasonable limit is
still set on systems with page sizes larger then 4K.
Reviewed-by: David Quigley <david.quigley@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#571
When DEBUG_KMEM_TRACKING is enabled in SPL, we keep tracking all
the buffers alloced by kmem_alloc() and kmem_zalloc(). If a NULL
pointer which indicates no track info in SPL is passed to
spl_kmem_free_track, we just ignore it.
Signed-off-by: GeLiXin <ge.lixin@zte.com.cn>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue zfsonlinux/zfs#4967
Closes#567
For non-rwsem-spinlocks the "count" member was changed from a
"long" to "atomic_long_t" type. A configure check has been
added to detect this change along with new versions of the
_rwsem_tryupgrade() function and RWSEM_COUNT() macro. See
https://github.com/torvalds/linux/commit/8ee62b18 for complete
details.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#563
