This change is designed to account for yet another difference between
illumos and FreeBSD VFS. In FreeBSD a filesystem driver is supposed to
clean up mnt_data in its VFS_UNMOUNT method because it's the last call
into the driver before a struct mount object is destroyed. The VFS
drains all references to the object before destroying it, but for the
driver it's already as good as gone.
In contrast, illumos VFS provides another method, VFS_FREEVFS, that is
called when all references are drained. So, the driver can keep its
data after VFS_UNMOUNT and clean it up in VFS_FREEVFS after all
references are gone. This is what ZFS does on illumos.
So there a reference to a filesystem is sufficient to guarantee that the
ZFS specific data, aka zfsvfs_t, stays around (even if the filesystem
gets unmounted). In FreeBSD we need to vfs_busy the filesystem to get
the same guarantee. vfs_ref guarantees only that the struct mount is
kept.
The following rules should be observed in getzfsvfs / getzfsvfs_impl on
FreeBSD:
- if we need access to zfsvfs_t then we must use vfs_busy
- if only we need to access struct mount (aka vfs_t), then vfs_ref is
enough
- when illumos code actually needs only the vfs_t, they still can pass
the zfsvfs_t and get the vfs_t from it; that can work in FreeBSD if
the filesystem is busied, but when it's just referenced then we have
to pass the vfs_t explicitly
- we cannot call vfs_busy while holding a dataset because that creates a
LOR with dp_config_rwlock
As a result:
- getzfsvfs_impl now only references the filesystem, same as in illumos,
but unlike illumos it has to return the vfs_t
- the consumers are updated to account for the change
- getzfsvfs busies the filesystem (and drops the reference from
getzfsvfs_impl)
Also, zfs_unmount_snap() now gets a busied a filesystem, references it
and then unbusies it essentially reverting actions done in getzfsvfs.
This is needed because the code may perform some checks that require the
zfsvfs_t. So, those are done before the unbusying.
MFC after: 2 weeks
vrele() acquires the vnode lock only if the hold count drops to zero.
In other scenarios it needs only the interlock. So,
zfsctl_snapdir_lookup() can race with vfs_mount_destroy() -> vrele()
such that the lookup adds a new reference and then vrele() drops the
mountpoint's reference and only then we check the reference count.
It would be just one in this case.
In fact, the assert should have been removed in r323483 when the code
learned how to deal with the uncovered vnode.
PR: 225795
MFC after: 4 days
X-MFC with: r329556
Now that we're queueing BIO_DELETE requests in the CAM I/O scheduler,
it make sense to try to combine as many as possible into a single
request to send down to hardware. Hopefully, lots of larger requests
like this are better than lots of individual transactions.
Note for future: need to limit based on total size of the trim
request. Should also collapse adjacent ranges where possible to
increase the size of the max payload.
Sponsored by: Netflix
Introduce flags word to describe the capacities of the peripheral.
First bit will describe if the periph driver allows multiple
outstanding TRIMS to be active in a device.
Modify the I/O scheduler so that the nda driver can queue trims
for a while after the first one arrives. We'll queue until we see
a I/O scheduler tick, then we'll schedule as many TRIMs as allowed
by other factors (currently this is slocts in the NVMe controller).
This mariginally helps the read latency issues we see with reads,
but sets the stage for the nda driver to do TRIM collapsing like the
da and ada drivers do today.
Sponsored by: Netflix
To help implement a policy of 'queue all trims until next I/O sched
tick' policy to help coalesce them, note when we tick so we can do
something special on the first call after the tick to get more work.
Sponsored by: Netflix
While the code for ada and da both assume that the trim list is
ordered when doing the coaleascing the TRIMs, it turns out that
creating the sorted list uses more resources than are saved by having
slightly fewer trims sent to the device.
Sponsored by: Netflix
9080 recursive enter of vdev_indirect_rwlock from vdev_indirect_remap()
illumos/illumos-gate@bdfded42e6
A scenario came up where a callback executed by vdev_indirect_remap() on a vdev, calls
vdev_indirect_remap() on the same vdev and tries to reacquire vdev_indirect_rwlock that
was already acquired from the first call to vdev_indirect_remap(). The specific scenario,
is that we want to remap a block pointer that is snapshoted but its dataset's remap_deadlist
is not cached. So in order to add it we issue a read through a vdev_indirect_remap() on the
same vdev, which brings up the aforementioned issue.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>
Author: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
9079 race condition in starting and ending condesing thread for indirect vdevs
illumos/illumos-gate@667ec66f1b
The timeline of the race condition is the following:
[1] Thread A is about to finish condesing the first vdev in spa_condense_indirect_thread(),
so it calls the spa_condense_indirect_complete_sync() sync task which sets the
spa_condensing_indirect field to NULL. Waiting for the sync task to finish, thread A
sleeps until the txg is done. When this happens, thread A will acquire spa_async_lock
and set spa_condense_thread to NULL.
[2] While thread A waits for the txg to finish, thread B which is running spa_sync() checks
whether it should condense the second vdev in vdev_indirect_should_condense() by checking
the spa_condensing_indirect field which was set to NULL by spa_condense_indirect_thread()
from thread A. So it goes on and tries to spawn a new condensing thread in
spa_condense_indirect_start_sync() and the aforementioned assertions fails because thread A
has not set spa_condense_thread to NULL (which is basically the last thing it does before
returning).
The main issue here is that we rely on both spa_condensing_indirect and spa_condense_thread to
signify whether a condensing thread is running. Ideally we would only use one throughout the
codebase. In addition, for managing spa_condense_thread we currently use spa_async_lock which
basically tights condensing to scrubing when it comes to pausing and resuming those actions
during spa export.
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Approved by: Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>
Author: Serapheim Dimitropoulos <serapheim@delphix.com>
9075 Improve ZFS pool import/load process and corrupted pool recovery
illumos/illumos-gate@6f7938128a
Some work has been done lately to improve the debugability of the ZFS pool
load (and import) process. This includes:
https://www.illumos.org/issues/7638: Refactor spa_load_impl into several functions
https://www.illumos.org/issues/8961: SPA load/import should tell us why it failed
https://www.illumos.org/issues/7277: zdb should be able to print zfs_dbgmsg's
To iterate on top of that, there's a few changes that were made to make the
import process more resilient and crash free. One of the first tasks during the
pool load process is to parse a config provided from userland that describes
what devices the pool is composed of. A vdev tree is generated from that config,
and then all the vdevs are opened.
The Meta Object Set (MOS) of the pool is accessed, and several metadata objects
that are necessary to load the pool are read. The exact configuration of the
pool is also stored inside the MOS. Since the configuration provided from
userland is external and might not accurately describe the vdev tree
of the pool at the txg that is being loaded, it cannot be relied upon to safely
operate the pool. For that reason, the configuration in the MOS is read early
on. In the past, the two configurations were compared together and if there was
a mismatch then the load process was aborted and an error was returned.
The latter was a good way to ensure a pool does not get corrupted, however it
made the pool load process needlessly fragile in cases where the vdev
configuration changed or the userland configuration was outdated. Since the MOS
is stored in 3 copies, the configuration provided by userland doesn't have to be
perfect in order to read its contents. Hence, a new approach has been adopted:
The pool is first opened with the untrusted userland configuration just so that
the real configuration can be read from the MOS. The trusted MOS configuration
is then used to generate a new vdev tree and the pool is re-opened.
When the pool is opened with an untrusted configuration, writes are disabled
to avoid accidentally damaging it. During reads, some sanity checks are
performed on block pointers to see if each DVA points to a known vdev;
when the configuration is untrusted, instead of panicking the system if those
checks fail we simply avoid issuing reads to the invalid DVAs.
This new two-step pool load process now allows rewinding pools accross
vdev tree changes such as device replacement, addition, etc. Loading a pool
from an external config file in a clustering environment also becomes much
safer now since the pool will import even if the config is outdated and didn't,
for instance, register a recent device addition.
With this code in place, it became relatively easy to implement a
long-sought-after feature: the ability to import a pool with missing top level
(i.e. non-redundant) devices. Note that since this almost guarantees some loss
Of data, this feature is for now restricted to a read-only import.
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Andrew Stormont <andyjstormont@gmail.com>
Approved by: Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>
Author: Pavel Zakharov <pavel.zakharov@delphix.com>
Trying to grab locks during cngrab() when entering the debugger is
deadlock prone as all other CPUs are already halted (and thus unable
to release locks) when cngrab() is invoked. One could instead use
try-locks. However, the case that the try-lock fails still has to
be handled. In addition, if the try-lock works it doesn't provide
any greater ordering guarantees than is already provided by entering
and exiting DDB. It is simpler to define a simpler path for the
case that the try-lock would fail and always use that when entering
DDB. Messing with timers, etc. when entering DDB is dubious even if
the try-lock succeeds.
This patch attempts to use the smallest possible set of operations to
grab the vt(4) console when entering DDB without using any locks.
Reviewed by: emaste
Tested by: Matthew Macy
MFC after: 1 week
This consolidates all of the DDP state in one place. Also, the code has
now been fixed to ensure that DDP state is only accessed for DDP
connections. This should not be a functional change but makes it cleaner
and easier to add state for other TOE socket modes in the future.
MFC after: 1 month
Sponsored by: Chelsio Communications
illumos/illumos-gate@add927f8c8
Reported on the ZFSonLinux https://github.com/zfsonlinux/zfs/issues/4843,
fixed by https://github.com/zfsonlinux/zfs/pull/6339:
If we are in the middle of an incremental zfs receive, the child .../%recv
will exist. If you concurrently run zfs promote .../%recv, it will "work",
but then zfs gets confused. For example, there's no obvious way to destroy
the containing filesystem (because it is now a clone of its invisible child).
Attempting to do this promote should be an error. We could fix this by
having zfs_ioc_promote() check if zc_name contains a %, similar to
zfs_ioc_rename().
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: loli10K <ezomori.nozomu@gmail.com>
illumos/illumos-gate@f4c1745bd6
Illumos 4080 allows "zpool clear" to work on readonly pools: i don't think
this is the intended behaviour, we shouldn't be allowed to clear readonly
pools. Probably.
A fix is already in the ZFS on Linux repository to addess this issue:
92e43c1718
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: loli10K <ezomori.nozomu@gmail.com>
8408 dsl_props_set_sync_impl() does not handle nested nvlists correctly
illumos/illumos-gate@85723e5eec
When iterating over the input nvlist in dsl_props_set_sync_impl() when we
don't preserve the nvpair name before looking up ZPROP_VALUE, so when we
later go to process it nvpair_name() is always "value" instead of the actual
property name.
This results in a couple of bugs in the recv code:
- received properties are not restored correctly when failing to receive
an incremental send stream
- received properties are not completely replaced by the new ones when
successfully receiving an incremental send stream
This was discovered on ZFS on Linux (fixed in
5f1346c299)
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: loli10K <ezomori.nozomu@gmail.com>
illumos/illumos-gate@46ac8fdfc5
Reviewed by: Yuri Pankov <yuripv@yuripv.net>
Reviewed by: Andy Fiddaman <omnios@citrus-it.co.uk>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Toomas Soome <tsoome@me.com>
illumos/illumos-gate@e144c4e6c9
Currently `zdb` consistently fails to examine non-idle pools as it fails
during the `spa_load()` process. The main problem seems to be that
`spa_load_verify()` fails as can be seen below:
$ sudo zdb -d -G dcenter
zdb: can't open 'dcenter': I/O error
ZFS_DBGMSG(zdb):
spa_open_common: opening dcenter
spa_load(dcenter): LOADING
disk vdev '/dev/dsk/c4t11d0s0': best uberblock found for spa dcenter. txg 40824950
spa_load(dcenter): using uberblock with txg=40824950
spa_load(dcenter): UNLOADING
spa_load(dcenter): RELOADING
spa_load(dcenter): LOADING
disk vdev '/dev/dsk/c3t10d0s0': best uberblock found for spa dcenter. txg 40824952
spa_load(dcenter): using uberblock with txg=40824952
spa_load(dcenter): FAILED: spa_load_verify failed [error=5]
spa_load(dcenter): UNLOADING
This change makes `spa_load_verify()` a dryrun when ran from `zdb`. This is
done by creating a global flag in zfs and then setting it in `zdb`.
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Andy Stormont <astormont@racktopsystems.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Pavel Zakharov <pavel.zakharov@delphix.com>
These are a convenience for bhyve's debug server to use a single
ioctl for 'g' and 'G' rather than a loop of individual get/set
ioctl requests.
Reviewed by: grehan
MFC after: 2 months
Differential Revision: https://reviews.freebsd.org/D14074
illumos/illumos-gate@3ee8c80c74
When we fail to open or import a storage pool, we typically don't get any
additional diagnostic information, just "no pool found" or "can not import".
While there may be no additional user-consumable information, we should at
least make this situation easier to debug/diagnose for developers and support.
For example, we could start by using `zfs_dbgmsg()` to log each thing that we
try when importing, and which things failed. E.g. "tried uberblock of txg X
from label Y of device Z". Also, we could log each of the stages that we go
through in `spa_load_impl()`.
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Andrew Stormont <andyjstormont@gmail.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Pavel Zakharov <pavel.zakharov@delphix.com>
illumos/illumos-gate@1fd3785ff6
spa_load_impl has grown out of proportions. It is currently over 700
lines long and makes it very hard to follow or debug the import process
even for experienced ZFS developers. The objective is to split it up
in a series of well commented functions.
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Andrew Stormont <andyjstormont@gmail.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Pavel Zakharov <pavel.zakharov@delphix.com>
illumos/illumos-gate@36a64e6284
To prevent kmem_cache reaping from blocking other system resources, turn
kmem_cache_reap_now() (which blocks) into kmem_cache_reap_soon(). Callers
to kmem_cache_reap_soon() should use kmem_cache_reap_active(), which
exploits #9017's new taskq_empty().
Reviewed by: Bryan Cantrill <bryan@joyent.com>
Reviewed by: Dan McDonald <danmcd@joyent.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Yuri Pankov <yuripv@yuripv.net>
Author: Tim Kordas <tim.kordas@joyent.com>
FreeBSD does not use taskqueue for kmem caches reaping, so this change
is less dramatic then it is on Illumos, just limiting reaping to 1 time
per second. It may possibly be improved later, if needed.
illumos/illumos-gate@f06dce2c1f
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Gordon Ross <gordon.w.ross@gmail.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: Andrew Stormont <astormont@racktopsystems.com>
Only require a gateway to be specified on a route add request. On
a route change request that does not specify the gateway, the
gateway will remain the same. This allows changing other route
parameters without having to re-specifying the gateway, like in
"route change 10.0.0.0/8 -mtu 9000".
Update the route(8) manpage to explicitly call out this usage
as being supported.
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Reviewed By: eugen (rtsock.c change), rgrimes
Differential Revision: https://reviews.freebsd.org/D14291
illumos/illumos-gate@0fb055e81f
At present it is possible to boot from a root pool that is on RAIDZ but not
one that is on RAIDZ2 or RAIDZ3. This is because, at the time the pool
version is checked to ensure support for dual/triple parity, the uberblock
has not yet been loaded into the SPA and therefore the code determines that
the pool version is too old and returns ENOTSUP.
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Andy Stormont <astormont@racktopsystems.com>
Reviewed by: Toomas Soome <tsoome@me.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Andy Fiddaman <omnios@citrus-it.co.uk>
FreeBSD already had this fixed, so this is just a diff reduction.
illumos/illumos-gate@5cabbc6b49https://www.illumos.org/issues/7614:
This project allows top-level vdevs to be removed from the storage pool with
“zpool remove”, reducing the total amount of storage in the pool. This
operation copies all allocated regions of the device to be removed onto other
devices, recording the mapping from old to new location. After the removal is
complete, read and free operations to the removed (now “indirect”) vdev must
be remapped and performed at the new location on disk. The indirect mapping
table is kept in memory whenever the pool is loaded, so there is minimal
performance overhead when doing operations on the indirect vdev.
The size of the in-memory mapping table will be reduced when its entries
become “obsolete” because they are no longer used by any block pointers in
the pool. An entry becomes obsolete when all the blocks that use it are
freed. An entry can also become obsolete when all the snapshots that
reference it are deleted, and the block pointers that reference it have been
“remapped” in all filesystems/zvols (and clones). Whenever an indirect block
is written, all the block pointers in it will be “remapped” to their new
(concrete) locations if possible. This process can be accelerated by using
the “zfs remap” command to proactively rewrite all indirect blocks that
reference indirect (removed) vdevs.
Note that when a device is removed, we do not verify the checksum of the data
that is copied. This makes the process much faster, but if it were used on
redundant vdevs (i.e. mirror or raidz vdevs), it would be possible to copy
the wrong data, when we have the correct data on e.g. the other side of the
mirror. Therefore, mirror and raidz devices can not be removed.
Reviewed by: Alex Reece <alex@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Laager <rlaager@wiktel.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Approved by: Garrett D'Amore <garrett@damore.org>
Author: Prashanth Sreenivasa <pks@delphix.com>
Having these compiled into the module causes the kobj method descriptors
to be resolved incorrectly (by the compile-time linker instead of the
kernel linker), which then leads to hours of frustrating debugging.
illumos/illumos-gate@95643f75d295643f75d2https://www.illumos.org/issues/8520
lzc_rollback_to() should support rolling back to a clone's origin.
The current checks in zfs_ioc_rollback() would not allow that because the
origin snapshot belongs to a different filesystem.
The overly restrictive check was introduced in 7600, but it was not a
regression as none of the existing tools provided a way to rollback to the
origin.
https://www.illumos.org/issues/7198
EINVAL is returned when a dataset does not have any snapshots, so there is
nothing to roll back to.
Although the code in zfs_do_rollback checks for that condition in advance, it's
still possible that the snapshot(s) gets removed after the check and before the
rollback sync task is executed.
At the moment zfs command would crash when that happens.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Andriy Gapon <avg@FreeBSD.org>
MFC after: 2 weeks
illumos/illumos-gate@f864f99efef864f99efehttps://www.illumos.org/issues/8997
When dmu_tx_assign is called from zil_lwb_write_issue, it's possible
for either ERESTART or EIO to be returned.
If ERESTART is returned, this will cause an assertion to fail directly
in zil_lwb_write_issue, where the code assumes the return value is
EIO if dmu_tx_assign returns a non-zero value. This can occur if the
SPA is suspended when dmu_tx_assign is called, and most often occurs
when running zloop.
If EIO is returned, this can cause assertions to fail elsewhere in the
ZIL code. For example, zil_commit_waiter_timeout contains the
following logic:
lwb_t *nlwb = zil_lwb_write_issue(zilog, lwb);
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED);
In this case, if dmu_tx_assign returned EIO from within
zil_lwb_write_issue, the lwb variable passed in will not be issued
to disk. Thus, it's lwb_state field will remain LWB_STATE_OPENED and
this assertion will fail. zil_commit_waiter_timeout assumes that after
it calls zil_lwb_write_issue, the lwb will be issued to disk, and
doesn't handle the case where this is not true; i.e. it doesn't handle
the case where dmu_tx_assign returns EIO.
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Prakash Surya <prakash.surya@delphix.com>
MFC after: 3 weeks
illumos/illumos-gate@a6c1eb3c08a6c1eb3c08https://www.illumos.org/issues/8731
annotate_ecksum() asserts that nui64s, calculated as nui64s = size / sizeof
(uint64_t), is not greater than UINT16_MAX.
This restriction is needed because histograms of incorrectly set and cleared
bits have 16 bit counters and if the buffer consists of too many 64-bit words,
then a counter can potentially overflow producing an incorrect result.
When the largest buffer size was 128KB the greatest value of nui64s was 16K,
well within the limit.
But now we have support for large buffers and for buffer sizes of 512KB and
above the restriction is violated.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Andriy Gapon <avg@FreeBSD.org>
MFC after: 2 weeks
When processor enters power-save state it releases resources shared with other
cpu threads which makes other cores working much faster.
This patch also implements saving and restoring registers that might get
corrupted in power-save state.
Submitted by: Patryk Duda <pdk@semihalf.com>
Obtained from: Semihalf
Reviewed by: jhibbits, nwhitehorn, wma
Sponsored by: IBM, QCM Technologies
Differential revision: https://reviews.freebsd.org/D14330
binary mode user-space emulation layer. This is a regression issue after
r328436, when LinuxKPI character devices started to use DTYPE_DEV in
the "f_type" field of the associated file structure(s).
MFC after: 3 days
Found by: Johannes Lundberg <johalun0@gmail.com>
Sponsored by: Mellanox Technologies
Add function which can store RTC values to OPAL.
Submitted by: Wojciech Macek <wma@semihalf.org>
Obtained from: Semihalf
Sponsored by: IBM, QCM Technologies
Summary:
This compartmentalizes the CPU-specific trap components into its own
function, rather than littering the general printtrap() with various checks.
This will let us replace a series of #ifdef's with a runtime conditional check
in the future.
Reviewed By: nwhitehorn
Differential Revision: https://reviews.freebsd.org/D14416
illumos/illumos-gate@3f7978d02b3f7978d02bhttps://www.illumos.org/issues/8081
zdb(8) is full of minor problems that generate compiler warnings. On FreeBSD,
which uses -WError, the only way to build it is to disable all compiler
warnings. This makes it much harder to detect newly introduced bugs. We should
cleanup all the warnings.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: Alan Somers <asomers@gmail.com>
