The ZFS_ENTER/ZFS_EXIT/ZFS_VERFY_ZP macros should not be used
in the Linux zpl_*.c source files. They return a positive error
value which is correct for the common code, but not for the Linux
specific kernel code which expects a negative return value. The
ZPL_ENTER/ZPL_EXIT/ZPL_VERFY_ZP macros should be used instead.
Furthermore, the ZPL_EXIT macro has been updated to not call the
zfs_exit_fs() function. This prevents a possible deadlock which
can occur when a snapshot is automatically unmounted because the
zpl_show_devname() must never wait on in progress automatic
snapshot unmounts.
Reviewed-by: Adam Moss <c@yotes.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11169Closes#11201
The output of ZFS channel programs is logged on-disk in the zpool
history, and printed by `zpool history -i`. Channel programs can use
10MB of memory by default, and up to 100MB by using the `zfs program -m`
flag. Therefore their output can be up to some fraction of 100MB.
In addition to being somewhat wasteful of the limited space reserved for
the pool history (which for large pools is 1GB), in extreme cases this
can result in a failure of `ASSERT(length <= DMU_MAX_ACCESS);` in
`dmu_buf_hold_array_by_dnode()`.
This commit limits the output size that will be logged to 1MB. Larger
outputs will not be logged, instead a entry will be logged indicating
the size of the omitted output.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#11194
FreeBSD's VFS expects EFAULT from zfs_write() if we didn't complete
the full write so it can retry the operation. Add some missing
SET_ERRORs in zfs_write().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11193
This patch adds a new top-level vdev type called dRAID, which stands
for Distributed parity RAID. This pool configuration allows all dRAID
vdevs to participate when rebuilding to a distributed hot spare device.
This can substantially reduce the total time required to restore full
parity to pool with a failed device.
A dRAID pool can be created using the new top-level `draid` type.
Like `raidz`, the desired redundancy is specified after the type:
`draid[1,2,3]`. No additional information is required to create the
pool and reasonable default values will be chosen based on the number
of child vdevs in the dRAID vdev.
zpool create <pool> draid[1,2,3] <vdevs...>
Unlike raidz, additional optional dRAID configuration values can be
provided as part of the draid type as colon separated values. This
allows administrators to fully specify a layout for either performance
or capacity reasons. The supported options include:
zpool create <pool> \
draid[<parity>][:<data>d][:<children>c][:<spares>s] \
<vdevs...>
- draid[parity] - Parity level (default 1)
- draid[:<data>d] - Data devices per group (default 8)
- draid[:<children>c] - Expected number of child vdevs
- draid[:<spares>s] - Distributed hot spares (default 0)
Abbreviated example `zpool status` output for a 68 disk dRAID pool
with two distributed spares using special allocation classes.
```
pool: tank
state: ONLINE
config:
NAME STATE READ WRITE CKSUM
slag7 ONLINE 0 0 0
draid2:8d:68c:2s-0 ONLINE 0 0 0
L0 ONLINE 0 0 0
L1 ONLINE 0 0 0
...
U25 ONLINE 0 0 0
U26 ONLINE 0 0 0
spare-53 ONLINE 0 0 0
U27 ONLINE 0 0 0
draid2-0-0 ONLINE 0 0 0
U28 ONLINE 0 0 0
U29 ONLINE 0 0 0
...
U42 ONLINE 0 0 0
U43 ONLINE 0 0 0
special
mirror-1 ONLINE 0 0 0
L5 ONLINE 0 0 0
U5 ONLINE 0 0 0
mirror-2 ONLINE 0 0 0
L6 ONLINE 0 0 0
U6 ONLINE 0 0 0
spares
draid2-0-0 INUSE currently in use
draid2-0-1 AVAIL
```
When adding test coverage for the new dRAID vdev type the following
options were added to the ztest command. These options are leverages
by zloop.sh to test a wide range of dRAID configurations.
-K draid|raidz|random - kind of RAID to test
-D <value> - dRAID data drives per group
-S <value> - dRAID distributed hot spares
-R <value> - RAID parity (raidz or dRAID)
The zpool_create, zpool_import, redundancy, replacement and fault
test groups have all been updated provide test coverage for the
dRAID feature.
Co-authored-by: Isaac Huang <he.huang@intel.com>
Co-authored-by: Mark Maybee <mmaybee@cray.com>
Co-authored-by: Don Brady <don.brady@delphix.com>
Co-authored-by: Matthew Ahrens <mahrens@delphix.com>
Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Maybee <mmaybee@cray.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#10102
ZFS channel programs (invoked by `zfs program`) are executed in a LUA
sandbox with a limit on the amount of memory they can consume. The
limit is 10MB by default, and can be raised to 100MB with the `-m` flag.
If the memory limit is exceeded, the LUA program exits and the command
fails with a message like `Channel program execution failed: Memory
limit exhausted.`
The LUA sandbox allocates memory with `vmem_alloc(KM_NOSLEEP)`, which
will fail if the requested memory is not immediately available. In this
case, the program fails with the same message, `Memory limit exhausted`.
However, in this case the specified memory limit has not been reached,
and the memory may only be temporarily unavailable.
This commit changes the LUA memory allocator `zcp_lua_alloc()` to use
`vmem_alloc(KM_SLEEP)`, so that we won't spuriously fail when memory is
temporarily low. Instead, we rely on the system to be able to free up
memory (e.g. by evicting from the ARC), and we assume that even at the
highest memory limit of 100MB, the channel program will not truly
exhaust the system's memory.
External-issue: DLPX-71924
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#11190
The custom zpl_show_devname() helper should translate spaces in
to the octal escape sequence \040. The getmntent(2) function
is aware of this convention and properly translates the escape
character back to a space when reading the fsname.
Without this change the `zfs mount` and `zfs unmount` commands
incorrectly detect when a dataset with a name containing spaces
is mounted.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11182Closes#11187
It is a leftover from illumos always set to NULL and introducing a
spurious difference between zio_buf and zio_data_buf.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#11188
The microzap hash can sometimes be zero for single digit snapnames.
The zap cursor can then have a serialized value of two (for . and ..),
and skip the first entry in the avl tree for the .zfs/snapshot directory
listing, and therefore does not return all snapshots.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Cedric Berger <cedric@precidata.com>
Signed-off-by: Tony Perkins <tperkins@datto.com>
Closes#11039
The field is yet another leftover from unsupported zfs_znode_move.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#11186
We can consolidate the unlocking procedure into one place by starting
with drop_suspend set to B_FALSE and moving the open count check up.
While here, a little code cleanup. Match the out labels between
zvol_geom_open and zvol_cdev_open, and add a missing period in some
comments.
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11175
zvol_first_open can fail with EINTR if spa_namespace_lock is not held
and cannot be taken without waiting.
Apply the same logic that was done for zvol_geom_open to take
spa_namespace_lock if not already held on first open in zvol_cdev_open.
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11175
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11176
Show that these values will not be changing later.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11176
The oid comes from the znode we are already passing.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11176
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11176
After initial arc_c was reduced to arc_c_min it became possible that
on datasets with primarycache=metadata or none dirty data make up most
of ARC capacity and easily more than configured 50% of initial arc_c,
that causes forced txg commits by arc_tempreserve_space() and periodic
very long write delays.
This patch makes arc_tempreserve_space() to use arc_c only after ARC
warmed up once and arc_c really means something, but use arc_c_max
before that.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#11178
Fix a couple of places where the wrong tag is passed
to dnode_{hold, rele}
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#11184
Check if the ZVOL has been written before calling zil_async_to_sync.
The ZIL will be opened on the first write, not earlier.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mariusz Zaborski <oshogbo@vexillium.org>
Closes#11152
spa_config_load() passes NULL into resid when doing zfs_file_read().
This would trip over when vfs.zfs.autoimport_disable=0.
Sponsored by: The FreeBSD Foundation
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Ka Ho Ng <khng@freebsdfoundation.org>
Closes#11149
SET_ERROR is useful to trace errors, so use it where the errors occur
rather than factored out to the end of a function.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11146
A new function was added named revalidate_disk_size() and the old
revalidate_disk() appears to have been deprecated. As the only ZFS
code that calls this function is zvol_update_volsize, swapping the
old function call out for the new one should be all that is required.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#11085
Kernel 5.10 removed check_disk_change() in favor of callers using
the faster bdev_check_media_change() instead, and explicitly forcing
bdev revalidation when they desire that behavior. To preserve prior
behavior, I have wrapped this into a zfs_check_media_change() macro
that calls an inline function for the new API that mimics the old
behavior when check_disk_change() doesn't exist, and just calls
check_disk_change() if it exists.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#11085
Kernel commit 2b0d3d3e4fcfb brought in some changes to the struct
percpu_ref structure that moves most of its fields into a member
struct named "data" of type struct percpu_ref_data. This includes
the "count" member which is updated by vdev_blkg_tryget(), so update
this function to chase the API change, and detect it via configure.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#11085
Avoid checking the whole array of objects each time by removing the self
organized memory reaping. this can be managed by the global memory reap
callback which is called every 60 seconds. this will reduce the use if
locking operations significant.
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Closes#11126
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
Current CPU_SEQID users don't care about possibly changing CPU ID, but
enclose it within kpreempt disable/enable in order to fend off warnings
from Linux's CONFIG_DEBUG_PREEMPT.
There is no need to do it. The expected way to get CPU ID while allowing
for migration is to use raw_smp_processor_id.
In order to make this future-proof this patch keeps CPU_SEQID as is and
introduces CPU_SEQID_UNSTABLE instead, to make it clear that consumers
explicitly want this behavior.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#11142
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
zvol private data is supposed to be nulled by zvol_clear_private before
zvol_free is called as an indicator that the zvol is going away.
Implement zvol_clear_private for volmode=dev.
Assert that zvol_clear_private has been called before zvol_free.
Check that zvol_clear_private has not been called when updating
volsize. If it has, fail with ENXIO.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11117
Make sure to free doi in zvol_create_minor impl when make_dev_s fails.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11117
We fall back to a default volmode and continue when looking up a zvol's
volmode property fails. After this we should set the error to 0 to
ensure we take the success paths in the out section.
While here, make sure we only log that the zvol was created on success.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11117
Nonfunctional changes for readability and consistency.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11117
zvol_geom_close gets a count of the number of close operations to do.
Make sure we're always using this count to check if this will be the
last close operation performed on the zvol.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11117
Using more specific assert variants gives better messages on failure.
No functional change.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11117
Note that this only tracks sizes as requested by the caller.
Actual allocated space will almost always be bigger (e.g., rounded up to
the next power of 2 or page size). Additionally the allocated buffer may
be holding other areas hostage. Nonetheless, this is a starting point
for tracking memory usage in zstd.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#11129
While evaluating other assembler implementations it turns out that
the precomputed hash subkey tables vary in size, from 8*16 bytes
(avx2/avx512) up to 48*16 bytes (avx512-vaes), depending on the
implementation.
To be able to handle the size differences later, allocate
`gcm_Htable` dynamically rather then having a fixed size array, and
adapt consumers.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes#11102
While preparing #9749 some .cfi_{start,end}proc directives
were missed. Add the missing ones.
See upstream https://github.com/openssl/openssl/commit/275a048f
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes#11101
AT_BENEATH was merged to stable/12, where kern_unlinkat takes a
non-const path. DECONST the path passed to kern_unlinkat in the
case where AT_BENEATH is defined.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11139
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
L2ARC devices of several terabytes filled with 4KB blocks may take 15
minutes to rebuild. Due to the way L2ARC log reading is implemented
it is quite likely that for all that time rebuild thread will never
sleep. At least on FreeBSD kernel threads have absolute priority and
can not be preempted by threads with lower priorities. If some thread
is also bound to that specific CPU it may not get any CPU time for all
the 15 minutes.
Reviewed-by: Cedric Berger <cedric@precidata.com>
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Reviewed-by: George Amanakis <gamanakis@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes#11116
Refer to the correct section or alternative for FreeBSD and Linux.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11132
ZFS always waits for the write completion before flushing the cache.
That is why it does not require explicit ordering fences around it,
which are pretty difficult to implement for NVMe, since one has no
internal concept of strict request ordering.
This was already removed from FreeBSD once, but got resurrected
by mistake during OpenZFS merge.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes#11130
The port removed provisions for zfs_znode_move but the cleanup missed
this bit. To quote the original:
[snip]
list_insert_tail(&zfsvfs->z_all_znodes, zp);
membar_producer();
/*
* Everything else must be valid before assigning z_zfsvfs makes the
* znode eligible for zfs_znode_move().
*/
zp->z_zfsvfs = zfsvfs;
[/snip]
In the current code it is immediately followed by unlock which issues
the same fence, thus plays no role in correctness.
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#11115
The allocator does not provide the functionality to begin with.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#11114
The Linux kernel MODULE_LICENSE macro only recognizes a handful of
license strings and "MIT" is not one of the them. Update the macro
to use "Dual MIT/GPL" which is recognized and what the kernel expects
MIT licensed modules to use.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11112Closes#11113
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
It's even documented already.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11094
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 current l2_misses accounting behavior treats all reads to pools
without a configured l2arc as an l2arc miss, IFF there is at least
one other pool on the system which does have an l2arc configured.
This makes it extremely hard to tune for an improved l2arc hit/miss
ratio because this ratio will be modulated by reads from pools which
do not (and should not) have l2arc devices; its upper limit will
depend on the ratio of reads from l2arc'd pools and non-l2arc'd pools.
This PR prevents ARC reads affecting l2arc stats (n.b. l2_misses is
the only relevant one) where the target spa doesn't have an l2arc.
Includes new test - l2arc_l2miss_pos.ksh
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Amanakis <gamanakis@gmail.com>
Signed-off-by: Adam Moss <c@yotes.com>
Closes#10921