Commit Graph

777 Commits

Author SHA1 Message Date
Steven Hartland
2b114ad2a4 Add missing descriptions for ZFS sysctls
Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks
2013-03-21 11:25:21 +00:00
Steven Hartland
adea827b21 Optimisation of TRIM processing.
Previously TRIM processing was very bursty. This was made worse by the fact
that TRIM requests on SSD's are typically much slower than reads or writes.
This often resulted in stalls while large numbers of TRIM's where processed.

In addition due to the way the TRIM thread was only woken by writes, deletes
could stall in the queue for extensive periods of time.

This patch adds a number of controls to how often the TRIM thread for each
SPA processes its outstanding delete requests.
vfs.zfs.trim.timeout: Delay TRIMs by up to this many seconds
vfs.zfs.trim.txg_delay: Delay TRIMs by up to this many TXGs (reduced to 32)
vfs.zfs.vdev.trim_max_bytes: Maximum pending TRIM bytes for a vdev
vfs.zfs.vdev.trim_max_pending: Maximum pending TRIM segments for a vdev
vfs.zfs.trim.max_interval: Maximum interval between TRIM queue processing
(seconds)

Given the most common TRIM implementation is ATA TRIM the current defaults
are targeted at that.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks
2013-03-21 11:02:08 +00:00
Steven Hartland
6ad46cec23 Names the ZFS TRIM thread
Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks
2013-03-21 10:41:30 +00:00
Steven Hartland
89e5b43079 TRIM cache devices based on time instead of TXGs.
Currently, the trim module uses the same algorithm for data and cache
devices when deciding to issue TRIM requests, based on how far in the
past the TXG is.

Unfortunately, this is not ideal for cache devices, because the L2ARC
doesn't use the concept of TXGs at all. In fact, when using a pool for
reading only, the L2ARC is written but the TXG counter doesn't
increase, and so no new TRIM requests are issued to the cache device.

This patch fixes the issue by using time instead of the TXG number as
the criteria for trimming on cache devices. The basic delay principle
stays the same, but parameters are expressed in seconds instead of
TXGs. The new parameters are named trim_l2arc_limit and
trim_l2arc_batch, and both default to 30 second.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	17122c31ac
MFC after:	2 weeks
2013-03-21 10:29:05 +00:00
Steven Hartland
78ad0c1c80 Improve TXG handling in the TRIM module.
This patch adds some improvements to the way the trim module considers
TXGs:

 - Free ZIOs are registered with the TXG from the ZIO itself, not the
   current SPA syncing TXG (which may be out of date);
 - L2ARC are registered with a zero TXG number, as L2ARC has no concept
   of TXGs;
 - The TXG limit for issuing TRIMs is now computed from the last synced
   TXG, not the currently syncing TXG. Indeed, under extremely unlikely
   race conditions, there is a risk we could trim blocks which have been
   freed in a TXG that has not finished syncing, resulting in potential
   data corruption in case of a crash.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	5b46ad40d9
MFC after:	2 weeks
2013-03-21 10:16:10 +00:00
Steven Hartland
e07e3a3792 Don't register repair writes in the trim map.
The trim map inflight writes tree assumes non-conflicting writes, i.e.
that there will never be two simultaneous write I/Os to the same range
on the same vdev. This seemed like a sane assumption; however, in
actual testing, it appears that repair I/Os can very well conflict
with "normal" writes.

I'm not quite sure if these conflicting writes are supposed to happen
or not, but in the mean time, let's ignore repair writes for now. This
should be safe considering that, by definition, we never repair blocks
that are freed.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	Source: 6a3cebaf7c
2013-03-21 10:02:32 +00:00
Steven Hartland
e05aad2d33 Add TRIM support for L2ARC.
This adds TRIM support to cache vdevs. When ARC buffers are removed
from the L2ARC in arc_hdr_destroy(), arc_release() or l2arc_evict(),
the size previously occupied by the buffer gets scheduled for TRIMming.
As always, actual TRIMs are only issued to the L2ARC after
txg_trim_limit.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	31aae37399
MFC after:	2 weeks
2013-03-21 09:34:41 +00:00
Martin Matuska
192d547574 Release hold on pool before calling zvol_create_minor() 2013-03-20 09:56:20 +00:00
Martin Matuska
a0abc0d302 Run zvol_create_minors() only if in non-error case 2013-03-19 22:27:15 +00:00
Martin Matuska
e56718d734 Run zvol_create_minors() on snapshot creation 2013-03-19 22:14:50 +00:00
Martin Matuska
07091d8f14 MFV r247580:
Merge synctask code restructuring from vendor.

Modify forward and backward compatibility to support new change.

Illumos ZFS issues:
  3464 zfs synctask code needs restructuring

Sponsored by:	Hybrid Logic Ltd.
2013-03-19 12:51:18 +00:00
Martin Matuska
520268fb97 MFC @248493 2013-03-19 11:09:15 +00:00
Martin Matuska
87a5cb4650 Plug memory leak in dsl_check_snap_cb()
This was unnoticed because the function is very rarely used.

MFC after:	3 days
2013-03-19 07:47:51 +00:00
Martin Matuska
a602517b63 Add missing zvol_create_mirrors() on zfs_ioc_create() 2013-03-18 20:22:40 +00:00
John Baldwin
3cf3b9f097 Partially revert r195702. Deferring stops is now implemented via a set of
calls to toggle TDF_SBDRY rather than passing PBDRY to individual sleep
calls.
- Remove the stop_allowed parameters from cursig() and issignal().
  issignal() checks TDF_SBDRY directly.
- Remove the PBDRY and SLEEPQ_STOP_ON_BDRY flags.
2013-03-18 17:23:58 +00:00
Martin Matuska
876a84e867 MFC @248461 2013-03-18 09:39:51 +00:00
Martin Matuska
6f4accc2de Move common zfs ioctl compatibility functions (userland) into libzfs_compat.c
Introduce additional constants for zfs ioctl versions
2013-03-18 09:32:29 +00:00
Justin Hibbits
80a5635c8b Add FBT for PowerPC DTrace. Also, clean up the DTrace assembly code,
much of which is not necessary for PowerPC.

The FBT module can likely be factored into 3 separate files: common,
intel, and powerpc, rather than duplicating most of the code between
the x86 and PowerPC flavors.

All DTrace modules for PowerPC will be MFC'd together once Fasttrap is
completed.
2013-03-18 05:30:18 +00:00
Martin Matuska
af2e40ccd1 Merge libzfs_core part of r239388
Illumos ZFS issues:
  3085 zfs diff panics, then panics in a loop on booting

References:
  https://www.illumos.org/issues/3085
2013-03-17 18:49:11 +00:00
Martin Matuska
70b0720877 Fix accidentially changed ioc variable for old v15 compatibility 2013-03-17 17:28:06 +00:00
Martin Matuska
6cf922c88b Fix typo in sysctl description
Reported by:	Jeremy Chadwick
MFC after:	3 days
2013-03-17 15:53:27 +00:00
Martin Matuska
e2b4467975 libzfs_core:
- provide complete backwards compatibility (old utility, new kernel)
  - add zfs_cmd_t compatibility mapping in both directions
  - determine ioctl address in zfs_ioctl_compat.c
2013-03-17 10:57:04 +00:00
Martin Matuska
4f33cfb284 Initialize "error" variable where illumos does. 2013-03-16 20:28:38 +00:00
Martin Matuska
a03fbc7ecf MFC @248093 2013-03-09 11:57:51 +00:00
Attilio Rao
89f6b8632c Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
  - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
  - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
  - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
  - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
    (in order to avoid visibility of implementation details)
  - The read-mode operations are added:
    VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
    VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
  sys/mutex.h in consumers directly to cater its inlining functions
  using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
  consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
  the compat layer because the name clash between FreeBSD and solaris
  versions must be avoided.
  At this purpose zfs redefines the vm_object locking functions
  directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit.  Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by:	EMC / Isilon storage division
Reviewed by:	jeff
Reviewed by:	pjd (ZFS specific review)
Discussed with:	alc
Tested by:	pho
2013-03-09 02:32:23 +00:00
Attilio Rao
c934116100 Merge from vmc-playground:
Introduce a new KPI that verifies if the page cache is empty for a
specified vm_object.  This KPI does not make assumptions about the
locking in order to be used also for building assertions at init and
destroy time.
It is mostly used to hide implementation details of the page cache.

Sponsored by:	EMC / Isilon storage division
Reviewed by:	jeff
Reviewed by:	alc (vm_radix based version)
Tested by:	flo, pho, jhb, davide
2013-03-09 02:05:29 +00:00
Martin Matuska
91edf37414 Comment out unfeasible illumos copyin code and restore previous behavior. 2013-03-07 23:45:16 +00:00
Martin Matuska
b3b6851c78 Add missing init functions
Reduce diff to illumos
2013-03-06 11:33:25 +00:00
Xin LI
2f79ac7f21 Diff reduction with Illumos 2013-03-06 01:21:56 +00:00
Xin LI
227d24fc59 Use adx2 instead of adx in the second vsprintf, this fixes a
panic.
2013-03-05 22:58:53 +00:00
Martin Matuska
400c4069a5 MFV r247845:
Import ZFS bpobj bugfix from vendor.

Illumos ZFS issues:
  3603 panic from bpobj_enqueue_subobj()
  3604 zdb should print bpobjs more verbosely

References:
  https://www.illumos.org/issues/3603
  https://www.illumos.org/issues/3604

MFC after:	1 week
2013-03-05 18:54:41 +00:00
Martin Matuska
dce1a726f2 WiP merge of libzfs_core (MFV r238590, r238592)
not yet working, ioctl handling needs to be changed
2013-03-05 08:09:53 +00:00
Justin T. Gibbs
7e2a739f03 Fix assertion failure when using userland DTrace probes from
the pid provider on a kernel compiled with INVARIANTS.

sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c:
	In fasttrap_probe_pid(), attempts to write to the
	address space of the thread that fired the probe
	must be performed with the process of the thread
	held.  Use _PHOLD() to ensure this is the case.

	In fasttrap_probe_pid(), use proc_write_regs() instead
	of calling set_regs() directly.  proc_write_regs()
	performs invariant checks to verify the calling
	environment of set_regs().  PROC_LOCK()/UNLOCK() around
	the call to proc_write_regs() so that it's invariants
	are satisfied.

Sponsored by:	Spectra Logic Corporation
Reviewed by:	gnn, rpaulo
MFC after:	1 week
2013-03-04 22:07:36 +00:00
Rui Paulo
e0dffa2de2 Remove the extra parenthesis from the cv_init() macro. They are not
necessary because we already use parenthesis in zfs_cv_init().

This fixes a long standing bug where there would be an extra ")" at the
end of the string. This extra parenthesis would show up in the WCHAN of
the process (top, stty status, etc.).
2013-03-03 06:42:36 +00:00
Pawel Jakub Dawidek
2609222ab4 Merge Capsicum overhaul:
- Capability is no longer separate descriptor type. Now every descriptor
  has set of its own capability rights.

- The cap_new(2) system call is left, but it is no longer documented and
  should not be used in new code.

- The new syscall cap_rights_limit(2) should be used instead of
  cap_new(2), which limits capability rights of the given descriptor
  without creating a new one.

- The cap_getrights(2) syscall is renamed to cap_rights_get(2).

- If CAP_IOCTL capability right is present we can further reduce allowed
  ioctls list with the new cap_ioctls_limit(2) syscall. List of allowed
  ioctls can be retrived with cap_ioctls_get(2) syscall.

- If CAP_FCNTL capability right is present we can further reduce fcntls
  that can be used with the new cap_fcntls_limit(2) syscall and retrive
  them with cap_fcntls_get(2).

- To support ioctl and fcntl white-listing the filedesc structure was
  heavly modified.

- The audit subsystem, kdump and procstat tools were updated to
  recognize new syscalls.

- Capability rights were revised and eventhough I tried hard to provide
  backward API and ABI compatibility there are some incompatible changes
  that are described in detail below:

	CAP_CREATE old behaviour:
	- Allow for openat(2)+O_CREAT.
	- Allow for linkat(2).
	- Allow for symlinkat(2).
	CAP_CREATE new behaviour:
	- Allow for openat(2)+O_CREAT.

	Added CAP_LINKAT:
	- Allow for linkat(2). ABI: Reuses CAP_RMDIR bit.
	- Allow to be target for renameat(2).

	Added CAP_SYMLINKAT:
	- Allow for symlinkat(2).

	Removed CAP_DELETE. Old behaviour:
	- Allow for unlinkat(2) when removing non-directory object.
	- Allow to be source for renameat(2).

	Removed CAP_RMDIR. Old behaviour:
	- Allow for unlinkat(2) when removing directory.

	Added CAP_RENAMEAT:
	- Required for source directory for the renameat(2) syscall.

	Added CAP_UNLINKAT (effectively it replaces CAP_DELETE and CAP_RMDIR):
	- Allow for unlinkat(2) on any object.
	- Required if target of renameat(2) exists and will be removed by this
	  call.

	Removed CAP_MAPEXEC.

	CAP_MMAP old behaviour:
	- Allow for mmap(2) with any combination of PROT_NONE, PROT_READ and
	  PROT_WRITE.
	CAP_MMAP new behaviour:
	- Allow for mmap(2)+PROT_NONE.

	Added CAP_MMAP_R:
	- Allow for mmap(PROT_READ).
	Added CAP_MMAP_W:
	- Allow for mmap(PROT_WRITE).
	Added CAP_MMAP_X:
	- Allow for mmap(PROT_EXEC).
	Added CAP_MMAP_RW:
	- Allow for mmap(PROT_READ | PROT_WRITE).
	Added CAP_MMAP_RX:
	- Allow for mmap(PROT_READ | PROT_EXEC).
	Added CAP_MMAP_WX:
	- Allow for mmap(PROT_WRITE | PROT_EXEC).
	Added CAP_MMAP_RWX:
	- Allow for mmap(PROT_READ | PROT_WRITE | PROT_EXEC).

	Renamed CAP_MKDIR to CAP_MKDIRAT.
	Renamed CAP_MKFIFO to CAP_MKFIFOAT.
	Renamed CAP_MKNODE to CAP_MKNODEAT.

	CAP_READ old behaviour:
	- Allow pread(2).
	- Disallow read(2), readv(2) (if there is no CAP_SEEK).
	CAP_READ new behaviour:
	- Allow read(2), readv(2).
	- Disallow pread(2) (CAP_SEEK was also required).

	CAP_WRITE old behaviour:
	- Allow pwrite(2).
	- Disallow write(2), writev(2) (if there is no CAP_SEEK).
	CAP_WRITE new behaviour:
	- Allow write(2), writev(2).
	- Disallow pwrite(2) (CAP_SEEK was also required).

	Added convinient defines:

	#define	CAP_PREAD		(CAP_SEEK | CAP_READ)
	#define	CAP_PWRITE		(CAP_SEEK | CAP_WRITE)
	#define	CAP_MMAP_R		(CAP_MMAP | CAP_SEEK | CAP_READ)
	#define	CAP_MMAP_W		(CAP_MMAP | CAP_SEEK | CAP_WRITE)
	#define	CAP_MMAP_X		(CAP_MMAP | CAP_SEEK | 0x0000000000000008ULL)
	#define	CAP_MMAP_RW		(CAP_MMAP_R | CAP_MMAP_W)
	#define	CAP_MMAP_RX		(CAP_MMAP_R | CAP_MMAP_X)
	#define	CAP_MMAP_WX		(CAP_MMAP_W | CAP_MMAP_X)
	#define	CAP_MMAP_RWX		(CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X)
	#define	CAP_RECV		CAP_READ
	#define	CAP_SEND		CAP_WRITE

	#define	CAP_SOCK_CLIENT \
		(CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT | \
		 CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN)
	#define	CAP_SOCK_SERVER \
		(CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME | \
		 CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND | \
		 CAP_SETSOCKOPT | CAP_SHUTDOWN)

	Added defines for backward API compatibility:

	#define	CAP_MAPEXEC		CAP_MMAP_X
	#define	CAP_DELETE		CAP_UNLINKAT
	#define	CAP_MKDIR		CAP_MKDIRAT
	#define	CAP_RMDIR		CAP_UNLINKAT
	#define	CAP_MKFIFO		CAP_MKFIFOAT
	#define	CAP_MKNOD		CAP_MKNODAT
	#define	CAP_SOCK_ALL		(CAP_SOCK_CLIENT | CAP_SOCK_SERVER)

Sponsored by:	The FreeBSD Foundation
Reviewed by:	Christoph Mallon <christoph.mallon@gmx.de>
Many aspects discussed with:	rwatson, benl, jonathan
ABI compatibility discussed with:	kib
2013-03-02 00:53:12 +00:00
Xin LI
5c737b11df MFV r247575:
Import a fix tighten assertion on SPA versions from vendor (Illumos).

Illumos ZFS issue:

  3543 Feature flags causes assertion in spa.c to miss certain cases

MFC after:	2 weeks
2013-03-01 22:20:13 +00:00
Martin Matuska
4abd59512a MFV r247316:
Merge new read-only zfs properties from vendor (illumos)

Illumos ZFS issues:
  3588 provide zfs properties for logical (uncompressed) space used and
       referenced

References:
  https://www.illumos.org/issues/3588

MFC after:	2 weeks
2013-03-01 21:58:51 +00:00
Martin Matuska
bb508e7732 Fix the zfs_ioctl compat layer to support zfs_cmd size change introduced
in r247265 (ZFS deadman thread). Both new utilities now support the old
kernel and new kernel properly detects old utilities.

For future backwards compatibility, the vfs.zfs.version.ioctl read-only
sysctl has been introduced. With this sysctl zfs utilities will be able
to detect the ioctl interface version of the currently loaded zfs module.

As a side effect, the zfs utilities between r247265 and this revision don't
support the old kernel module. If you are using HEAD newer or equal than
r247265, install the new kernel module (or whole kernel) first.

MFC after:	10 days
2013-03-01 09:42:58 +00:00
Martin Matuska
24245e76ea MFV 247176, 247178, 247315:
Import metaslab_sync() speedup from vendor (illumos).

Illumos ZFS issues:
  3552 condensing one space map burns 3 seconds of CPU in spa_sync() thread
  3564 spa_sync() spends 5-10% of its time in metaslab_sync() (when not
       condensing)
  3578 transferring the freed map to the defer map should be constant time
  3579 ztest trips assertion in metaslab_weight()

References:
  https://www.illumos.org/issues/3552
  https://www.illumos.org/issues/3564
  https://www.illumos.org/issues/3578
  https://www.illumos.org/issues/3579

MFC after:	2 weeks
2013-02-27 14:45:23 +00:00
Martin Matuska
e4428d63a8 Be more verbose on ZFS deadman I/O panic
Patch suggested upstream.

Suggested by:	Olivier Cinquin
MFC after:	12 days
2013-02-26 20:41:27 +00:00
Martin Matuska
e70664bafc MFV v242732:
Merge the ZFS I/O deadman thread from vendor (illumos).
This feature panics the system on hanging ZFS I/O, helps debugging
and resumes failed service.

The panic behavior can be controlled with the loader-only tunables:
vfs.zfs.deadman_enabled (enable or disable panic on stalled ZFS I/O)
vfs.zfs.deadman_synctime (expiration time for stalled ZFS I/O)

By default, ZFS I/O deadman is enabled by default on amd64 and i386
excluding virtual guest machines.

Illumos ZFS issues:
  3246 ZFS I/O deadman thread

References:
  https://www.illumos.org/issues/3246

MFC after:	2 weeks
2013-02-25 12:33:31 +00:00
Martin Matuska
781c0f87d3 MFV r246653:
Import vendor change to avoid "unitialized variable" warnings.

Illumos ZFS issues:
  3522 zfs module should not allow uninitialized variables

References:
  https://www.illumos.org/issues/3522
2013-02-23 11:21:05 +00:00
Justin T. Gibbs
6a8f90edf5 Avoid panic when tearing down the DTrace pid provider for a
process that has crashed.

sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c:
	In fasttrap_pid_disable(), we cannot PHOLD the proc
	structure for a process that no longer exists, but
	we still have other, fasttrap specific, state that
	must be cleaned up for probes that existed in the
	dead process.  Instead of returning early if the
	process related to our probes isn't found,
	conditionalize the locking and carry on with a NULL
	proc pointer.  The rest of the fasttrap code already
	understands that a NULL proc is possible and does
	the right things in this case.

Sponsored by:	Spectra Logic Corporation
Reviewed by:	rpaulo, gnn
MFC after:	1 week
2013-02-20 17:55:17 +00:00
Xin LI
e469d5a70f Eliminate real_LZ4_uncompress. It's unused and does not perform sufficient
check against input stream (i.e. it could read beyond specified input
buffer).
2013-02-14 21:02:18 +00:00
Martin Matuska
7c695febc9 Change vfs.zfs.write_to_degraded from CTLFLAG_RW to CTLFLAG_RWTUN
Suggested by:	pjd
2013-02-13 23:11:25 +00:00
Xin LI
314caba11c Restore De Bruijn algorithm for sparc64 where the compiler rely on a
library function for __builtin_c?z.

Tested by:	Michael Moll <kvedulv kvedulv de>
2013-02-13 17:30:54 +00:00
Martin Matuska
6a33bbc041 Merge zfs_ioctl.c code that should have been merged together with ZFS v28.
Fixes several problems if working with read-only pools.

Changed code originaly introduced in onnv-gate 13061:bda0decf867b
Contains changes up to illumos-gate 13700:4bc0783f6064

PR:		kern/175897
Suggested by:	avg

MFC after:	2 weeks
2013-02-11 21:10:55 +00:00
Martin Matuska
9689178c3f MFV r246633:
Import vendor bugfixes regarding SA rounding, header size and layout.
This was already partially fixed by avg.

Illumos ZFS issues:
  3512 rounding discrepancy in sa_find_sizes()
  3513 mismatch between SA header size and layout

References:
  https://www.illumos.org/issues/3512
  https://www.illumos.org/issues/3513

MFC after:	2 weeks
2013-02-11 14:29:38 +00:00
Martin Matuska
bb03847418 MFV r246394:
Add tunable to allow block allocation on degraded vdevs.

Illumos ZFS issues:
  3507 Tunable to allow block allocation even on degraded vdevs

References:
  https://www.illumos.org/issues/3507

MFC after:	2 weeks
2013-02-11 13:59:57 +00:00
Martin Matuska
ff20578569 MFV r246392:
Import vendor ZFS bugfix fixing a possible deadlock in arc_read().

Illumos ZFS issues:
  3498 panic in arc_read(): !refcount_is_zero(&pbuf->b_hdr->b_refcnt)

References:
  https://www.illumos.org/issues/3498

MFC after:	2 weeks
2013-02-11 12:42:11 +00:00