within the CHROOTDIR. If it does not exist, unset CHROOTBUILD_SKIP
to prevent build failures.
Requested by: swills
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
MSI/MSI-x interrupts are edge-triggered. If an interrupt
arrives when IRQ line is masked, it will be lost and will
never recover. Perform MSI_EOI always after unmask to give
a chance for PHB/XICS to send an interrupt again if MSI/MSI-x
pending bit is set in MSI/MSI-x BAR space.
Submitted by: Wojciech Macek <wma@semihalf.org>
Obtained from: Semihalf
Sponsored by: IBM, QCM Technologies
Increment the route table generation count after modifying a
route. This signals back to TCP connections that they need to
update their L2 caches as the gateway for their route may have
changed. This is a heavier hammer than is needed, strictly
speaking, but route changes will be unlikely enough that the
performance effects of invalidating all connection route caches
should be negligible.
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D13990
Reviewed by: karels
Add a new macro to clear both the L3 and L2 route caches, to
hopefully prevent future instances where only the L3 cache was
cleared when both should have been.
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D13989
Reviewed by: karels
When the inpcb route cache is invalidated after a change to the
routing tables, we need to invalidate the LLE cache as well.
Previous to this change packets for the connection would continue
to use the old L2 information from the old L3 gateway, and the
packets for the connection would likely be blackholed.
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D13988
Reviewed by: karels
Commits r326203 and r326978 broke 64-bit booke kernels by introducing a 1MB
zero-pad between the ELF header and the start of the kernel. This didn't
cause a build failure, but caused kernels to need to be loaded into memory
1MB lower, which could easily break scripts expecting previous behavior.
This change matches the similar change made to AIM in r327358.
The man page is years out of date regarding errors. Our implementation _does_
allow unaligned addresses, and it _does_not_ check for negative lengths,
because the length is unsigned. It checks for overflow instead.
Update the tests accordingly.
Reviewed by: bcr
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D13826
In iflib, the device-specific init() function isn't supposed to edit
the struct ifnet driver flags. If it does, it'll cause an MPASS() assert
in iflib to fail.
PR: 225312
Reported by: bhughes@
Route messages are aligned to the host long type alignment, which
breaks 32bit.
Reported and tested by: lwhsu
Diagnosed by: Yuri Pankov <yuripv@icloud.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
kib points out that trying to re-use symbol versioning from libc is dirty
and wrong. The implementation in libregex is incompatible by design with the
implementation in libc. Using the symbol versions from libc can and likely
will cause confusions for linkers and bring unexpected behavior for
consumers that unwillingly (transitively) link against libregex.
Reported by: kib
These functions deal the same type of overflows we do with mallocarray(9).
Using our mallocarray will panic, which different from the previous
behavior (returning NULL), but neither behavior is more correct.
As a sidenote, drm_calloc_large() is not currently used at all.
Reviewed by: dumbbell
Differential Revision: https://reviews.freebsd.org/D13835
instead of frobbing the registers directly.
As a hack the bcm2835_pwm kmod presently ignores the 'status="disabled"'
in the RPI3 DTB, assuming that if you load the kld you probably
want the PWM to work.
illumos/illumos-gate@e9b7d6e7f7https://www.illumos.org/issues/8972:
'zfs holds -H' does not properly output content in scripted mode. It uses a
tab instead of two spaces, but it still pads column widths with spaces when
it should not.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Allan Jude <allanjude@freebsd.org>
illumos/illumos-gate@e9b7d6e7f7https://www.illumos.org/issues/8972:
'zfs holds -H' does not properly output content in scripted mode. It uses a
tab instead of two spaces, but it still pads column widths with spaces when
it should not.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Allan Jude <allanjude@freebsd.org>
illumos/illumos-gate@5cb8d943bchttps://www.illumos.org/issues/8835:
Sequential reads not aligned to block size are not detected by ZFS
prefetcher as sequential, killing prefetch and severely hurting
performance. It is caused by dmu_zfetch() in case of misaligned
sequential accesses being called with overlap of one block.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Allan Jude <allanjude@freebsd.org>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Alexander Motin <mav@FreeBSD.org>
illumos/illumos-gate@5cb8d943bchttps://www.illumos.org/issues/8835:
Sequential reads not aligned to block size are not detected by ZFS
prefetcher as sequential, killing prefetch and severely hurting
performance. It is caused by dmu_zfetch() in case of misaligned
sequential accesses being called with overlap of one block.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Allan Jude <allanjude@freebsd.org>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Alexander Motin <mav@FreeBSD.org>
illumos/illumos-gate@4ae5f5f06chttps://www.illumos.org/issues/8652:
Clang and GCC prefer to use unsigned ints to store enums. With Clang, that
causes tautological comparison warnings when comparing a zfs_prop_t or
zpool_prop_t variable to the macro ZPROP_INVAL. It's likely that error
handling code is being silently removed as a result.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Alan Somers <asomers@gmail.com>
illumos/illumos-gate@4ae5f5f06chttps://www.illumos.org/issues/8652:
Clang and GCC prefer to use unsigned ints to store enums. With Clang, that
causes tautological comparison warnings when comparing a zfs_prop_t or
zpool_prop_t variable to the macro ZPROP_INVAL. It's likely that error
handling code is being silently removed as a result.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Alan Somers <asomers@gmail.com>
8641 "zpool clear" and "zinject" don't work on "spare" or "replacing" vdevs
illumos/illumos-gate@2ba5f978a4https://www.illumos.org/issues/8641:
"zpool clear" and "zinject -d" can both operate on specific vdevs, either
leaf or interior. However, due to an oversight, neither works on a "spare"
or "replacing" vdev. For example:
sudo zpool create foo raidz1 c1t5000CCA000081D61d0 c1t5000CCA000186235d0 spare c
1t5000CCA000094115d0
sudo zpool replace foo c1t5000CCA000186235d0 c1t5000CCA000094115d0
$ zpool status foo pool: foo
state: ONLINE
scan: resilvered 81.5K in 0h0m with 0 errors on Fri Sep 8 10:53:03 2017
config:
NAME STATE READ WRITE CKSUM
foo ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
c1t5000CCA000081D61d0 ONLINE 0 0 0
spare-1 ONLINE 0 0 0
c1t5000CCA000186235d0 ONLINE 0 0 0
c1t5000CCA000094115d0 ONLINE 0 0 0
spares
c1t5000CCA000094115d0 INUSE currently in use
$ sudo zinject -d spare-1 -A degrade foo
cannot find device 'spare-1' in pool 'foo'
$ sudo zpool clear foo spare-1
cannot clear errors for spare-1: no such device in pool
Even though there was nothing to clear, those commands shouldn't have
reported an error. by contrast, trying to clear "raidz1-0" works just fine:
$ sudo zpool clear foo raidz1-0
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Alan Somers <asomers@gmail.com>
illumos/illumos-gate@2ba5f978a4https://www.illumos.org/issues/8641:
"zpool clear" and "zinject -d" can both operate on specific vdevs, either
leaf or interior. However, due to an oversight, neither works on a "spare"
or "replacing" vdev. For example:
sudo zpool create foo raidz1 c1t5000CCA000081D61d0 c1t5000CCA000186235d0 spare c1t5000CCA000094115d0
sudo zpool replace foo c1t5000CCA000186235d0 c1t5000CCA000094115d0
$ zpool status foo pool: foo
state: ONLINE
scan: resilvered 81.5K in 0h0m with 0 errors on Fri Sep 8 10:53:03 2017
config:
NAME STATE READ WRITE CKSUM
foo ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
c1t5000CCA000081D61d0 ONLINE 0 0 0
spare-1 ONLINE 0 0 0
c1t5000CCA000186235d0 ONLINE 0 0 0
c1t5000CCA000094115d0 ONLINE 0 0 0
spares
c1t5000CCA000094115d0 INUSE currently in use
$ sudo zinject -d spare-1 -A degrade foo
cannot find device 'spare-1' in pool 'foo'
$ sudo zpool clear foo spare-1
cannot clear errors for spare-1: no such device in pool
Even though there was nothing to clear, those commands shouldn't have
reported an error. by contrast, trying to clear "raidz1-0" works just fine:
$ sudo zpool clear foo raidz1-0
illumos/illumos-gate@301fd1d6f2
Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Sean Eric Fagan <sef@ixsystems.com>
illumos/illumos-gate@301fd1d6f2
Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Sean Eric Fagan <sef@ixsystems.com>
illumos/illumos-gate@01a059ee0chttps://www.illumos.org/issues/8856:
arc_cksum_is_equal() calls zio_push_transform() that requires abd_t*
(second arg), but a void* is passed.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Roman Strashkin <roman.strashkin@nexenta.com>
illumos/illumos-gate@01a059ee0chttps://www.illumos.org/issues/8856:
arc_cksum_is_equal() calls zio_push_transform() that requires abd_t*
(second arg), but a void* is passed.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Roman Strashkin <roman.strashkin@nexenta.com>
The introduced -j option is highly dependant on the ordering of arguments,
and it exhibited broken behavior in some other circumstances. Fix these
issues, and simplify the feature by removing the unneessary double parsing
of options.
Reviewed by: jilles
Differential Revision: https://reviews.freebsd.org/D13952
It's become clear that my armv7 builds didn't catch all of the warnings that
other builds are picking up, drop WARNS to 2 to match libc until they're all
caught.
regcomp uses some libc internal collation bits that are not available in the
libregex context. It's easy enough to bring in the needed parts that can
work in a libregex world, so do so.
Pointy hat to: me
libregex is a regex(3) implementation intended to feature GNU extensions and
any other non-POSIX compliant extensions that are deemed worthy.
These extensions are separated out into a separate library for the sake of
not cluttering up libc further with them as well as not deteriorating the
speed (or lack thereof) of the libc implementation.
libregex is implemented as a build of the libc implementation with LIBREGEX
defined to distinguish this from a libc build. The reasons for
implementation like this are two-fold:
1.) Maintenance- This reduces the overhead induced by adding yet another
regex implementation to base.
2.) Ease of use- Flipping on GNU extensions will be as simple as linking
against libregex, and POSIX-compliant compilations can be guaranteed with a
REG_POSIX cflag that should be ignored by libc/regex and disables extensions
in libregex. It is also easier to keep REG_POSIX sane and POSIX pure when
implemented in this fashion.
Tests are added for future functionality, but left disconnected for the time
being while other testing is done.
Reviewed by: cem (previous version)
Differential Revision: https://reviews.freebsd.org/D12934
When allocating memory through malloc(9), we always expect the amount of
memory requested to be unsigned as a negative value would either stand for
an error or an overflow.
Unsign some values, found when considering the use of mallocarray(9), to
avoid unnecessary casting. Also consider that indexes should be of
at least the same size/type as the upper limit they pretend to index.
MFC after: 3 weeks
8898 creating fs with checksum=skein on the boot pools fails ungracefully
illumos/illumos-gate@9fa2266d9ahttps://www.illumos.org/issues/8898:
# zfs create -o checksum=skein rpool/test
internal error: Result too large
Abort (core dumped)
Not a big deal per se, but should be handled correctly.
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Andy Stormont <astormont@racktopsystems.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Yuri Pankov <yuri.pankov@nexenta.com>
PR: 222199
illumos/illumos-gate@9a551dd645https://www.illumos.org/issues/8897:
# zpool online -e test mirror-1
Assertion failed: nvlist_lookup_string(tgt, "path", &pathname) == 0, file ../common/libzfs_pool.c, line 2558, function zpool_vdev_online
Abort (core dumped)
Not a big deal per se, but should be handled gracefully, same way as 'offline' and 'online' without '-e'.
Also reported as: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221408
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Yuri Pankov <yuri.pankov@nexenta.com>
illumos/illumos-gate@9a551dd645https://www.illumos.org/issues/8897:
# zpool online -e test mirror-1
Assertion failed: nvlist_lookup_string(tgt, "path", &pathname) == 0, file ../common/libzfs_pool.c, line 2558, function zpool_vdev_online
Abort (core dumped)
Not a big deal per se, but should be handled gracefully, same way as 'offline' and 'online' without '-e'.
Also reported as: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221408
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Yuri Pankov <yuri.pankov@nexenta.com>
8930 zfs_zinactive: do not remove the node if the filesystem is readonly
illumos/illumos-gate@93c618e0f4https://www.illumos.org/issues/8930:
We normally remove an unlinked node when its last user goes away and the
node becomes inactive. However, we should not do that if the filesystem
is mounted read-only including the case where it has its readonly
property set. The node will remain on the unlinked queue, so it will
not be leaked.
One particular scenario is when we receive an incremental stream into a
mounted read-only filesystem and that stream contains an unlinked file
(still on the unlinked queue). If that file is opened before the
receive and some time later after the receive it becomes inactive we
would remove it and, thus, modify the read-only filesystem. As a
result, the filesystem would diverge from its source and further
incremental receives would not be possible (without forcing a rollback).
Another related scenario, that may or may not be possible depending on an
OS / VFS policy, is when an open file is unlinked, then the filesystem is
remounted read-only, and then the file is closed.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Andriy Gapon <avg@FreeBSD.org>
illumos/illumos-gate@93c618e0f4https://www.illumos.org/issues/8930:
We normally remove an unlinked node when its last user goes away and the
node becomes inactive. However, we should not do that if the filesystem
is mounted read-only including the case where it has its readonly
property set. The node will remain on the unlinked queue, so it will
not be leaked.
One particular scenario is when we receive an incremental stream into a
mounted read-only filesystem and that stream contains an unlinked file
(still on the unlinked queue). If that file is opened before the
receive and some time later after the receive it becomes inactive we
would remove it and, thus, modify the read-only filesystem. As a
result, the filesystem would diverge from its source and further
incremental receives would not be possible (without forcing a rollback).
Another related scenario, that may or may not be possible depending on an
OS / VFS policy, is when an open file is unlinked, then the filesystem is
remounted read-only, and then the file is closed.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Andriy Gapon <avg@FreeBSD.org>
illumos/illumos-gate@94ddd0900ahttps://www.illumos.org/issues/8909:
There's a race condition that exists if `zil_free_lwb` races with either
`zil_commit_waiter_timeout` and/or `zil_lwb_flush_vdevs_done`.
Here's an example panic due to this bug:
> ::status
debugging crash dump vmcore.0 (64-bit) from ip-10-110-205-40
operating system: 5.11 dlpx-5.2.2.0_2017-12-04-17-28-32b6ba51fb (i86pc)
image uuid: 4af0edfb-e58e-6ed8-cafc-d3e9167c7513
panic message:
BAD TRAP: type=e (#pf Page fault) rp=ffffff0010555970 addr=60 occurred in mo
dule "zfs" due to a NULL pointer dereference
dump content: kernel pages only
> $c
zio_shrink+0x12()
zil_lwb_write_issue+0x30d(ffffff03dcd15cc0, ffffff03e0730e20)
zil_commit_waiter_timeout+0xa2(ffffff03dcd15cc0, ffffff03d97ffcf8)
zil_commit_waiter+0xf3(ffffff03dcd15cc0, ffffff03d97ffcf8)
zil_commit+0x80(ffffff03dcd15cc0, 9a9)
zfs_write+0xc34(ffffff03dc38b140, ffffff0010555e60, 40, ffffff03e00fb758, 0)
fop_write+0x5b(ffffff03dc38b140, ffffff0010555e60, 40, ffffff03e00fb758, 0)
write+0x250(42, fffffd7ff4832000, 2000)
sys_syscall+0x177()
If there's an outstanding lwb that's in `zil_commit_waiter_timeout`
waiting to timeout, waiting on it's waiter's CV, we must be sure not to
call `zil_free_lwb`. If we end up calling `zil_free_lwb`, then that LWB
may be freed and can result in a use-after-free situation where the
stale lwb pointer stored in the `zil_commit_waiter_t` structure of the
thread waiting on the waiter's CV is used.
A similar situation can occur if an lwb is issued to disk, and thus in
the `LWB_STATE_ISSUED` state, and `zil_free_lwb` is called while the
disk is servicing that lwb. In this situation, the lwb will be freed by
`zil_free_lwb`, which will result in a use-after-free situation when the
lwb's zio completes, and `zil_lwb_flush_vdevs_done` is called.
This race condition is prevented in `zil_close` by calling `zil_commit`
before `zil_free_lwb` is called, which will ensure all outstanding (i.e.
all lwb's in the `LWB_STATE_OPEN` and/or `LWB_STATE_ISSUED` states)
reach the `LWB_STATE_DONE` state before the lwb's are freed
(`zil_commit` will not return untill all the lwb's are
`LWB_STATE_DONE`).
Further, this race condition is prevented in `zil_sync` by only calling
`zil_free_lwb` for lwb's that do not have their `lwb_buf` pointer set.
All lwb's not in the `LWB_STATE_DONE` state will have a non-null value
for this pointer; the pointer is only cleared in
`zil_lwb_flush_vdevs_done`, at which point the lwb's state will be
changed to `LWB_STATE_DONE`.
This race is present in `zil_suspend`, leading to this bug.
At first glance, it would appear as though this would not be true
because `zil_suspend` will call `zil_commit`, just like `zil_close`, but
the problem is that `zil_suspend` will set the zilog's `zl_suspend`
field prior to calling `zil_commit`. Further, in `zil_commit`, if
`zl_suspend` is set, `zil_commit` will take a special branch of logic
and use `txg_wait_synced` instead of performing the normal `zil_commit`
logic.
This call to `txg_wait_synced` might be good enough for the data to
reach disk safely before it returns, but it does not ensure that all
outstanding lwb's reach the `LWB_STATE_DONE` state before it returns.
This is because, if there's an lwb "stuck" in
`zil_commit_waiter_timeout`, waiting for it's lwb to timeout, it will
maintain a non-null value for it's `lwb_buf` field and thus `zil_sync`
will not free that lwb. Thus, even though the lwb's data is already on
disk, the lwb will be left lingering, waiting on the CV, and will
eventually timeout and be issued to disk even though the write is
unnesseary.
So, after `zil_commit` is called from `zil_suspend`, we incorrectly
assume that there are not outstanding lwb's, and proceed to free all
lwb's found on the zilog's lwb list. As a result, we free the lwb that
will later be used `zil_commit_waiter_timeout`.
Reviewed by: John Kennedy <jwk404@gmail.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Prakash Surya <prakash.surya@delphix.com>
illumos/illumos-gate@94ddd0900ahttps://www.illumos.org/issues/8909:
There's a race condition that exists if `zil_free_lwb` races with either
`zil_commit_waiter_timeout` and/or `zil_lwb_flush_vdevs_done`.
Here's an example panic due to this bug:
> ::status
debugging crash dump vmcore.0 (64-bit) from ip-10-110-205-40
operating system: 5.11 dlpx-5.2.2.0_2017-12-04-17-28-32b6ba51fb (i86pc)
image uuid: 4af0edfb-e58e-6ed8-cafc-d3e9167c7513
panic message:
BAD TRAP: type=e (#pf Page fault) rp=ffffff0010555970 addr=60 occurred in module "zfs" due to a NULL pointer dereference
dump content: kernel pages only
> $c
zio_shrink+0x12()
zil_lwb_write_issue+0x30d(ffffff03dcd15cc0, ffffff03e0730e20)
zil_commit_waiter_timeout+0xa2(ffffff03dcd15cc0, ffffff03d97ffcf8)
zil_commit_waiter+0xf3(ffffff03dcd15cc0, ffffff03d97ffcf8)
zil_commit+0x80(ffffff03dcd15cc0, 9a9)
zfs_write+0xc34(ffffff03dc38b140, ffffff0010555e60, 40, ffffff03e00fb758, 0)
fop_write+0x5b(ffffff03dc38b140, ffffff0010555e60, 40, ffffff03e00fb758, 0)
write+0x250(42, fffffd7ff4832000, 2000)
sys_syscall+0x177()
If there's an outstanding lwb that's in `zil_commit_waiter_timeout`
waiting to timeout, waiting on it's waiter's CV, we must be sure not to
call `zil_free_lwb`. If we end up calling `zil_free_lwb`, then that LWB
may be freed and can result in a use-after-free situation where the
stale lwb pointer stored in the `zil_commit_waiter_t` structure of the
thread waiting on the waiter's CV is used.
A similar situation can occur if an lwb is issued to disk, and thus in
the `LWB_STATE_ISSUED` state, and `zil_free_lwb` is called while the
disk is servicing that lwb. In this situation, the lwb will be freed by
`zil_free_lwb`, which will result in a use-after-free situation when the
lwb's zio completes, and `zil_lwb_flush_vdevs_done` is called.
This race condition is prevented in `zil_close` by calling `zil_commit`
before `zil_free_lwb` is called, which will ensure all outstanding (i.e.
all lwb's in the `LWB_STATE_OPEN` and/or `LWB_STATE_ISSUED` states)
reach the `LWB_STATE_DONE` state before the lwb's are freed
(`zil_commit` will not return untill all the lwb's are
`LWB_STATE_DONE`).
Further, this race condition is prevented in `zil_sync` by only calling
`zil_free_lwb` for lwb's that do not have their `lwb_buf` pointer set.
All lwb's not in the `LWB_STATE_DONE` state will have a non-null value
for this pointer; the pointer is only cleared in
`zil_lwb_flush_vdevs_done`, at which point the lwb's state will be
changed to `LWB_STATE_DONE`.
This race is present in `zil_suspend`, leading to this bug.
At first glance, it would appear as though this would not be true
because `zil_suspend` will call `zil_commit`, just like `zil_close`, but
the problem is that `zil_suspend` will set the zilog's `zl_suspend`
field prior to calling `zil_commit`. Further, in `zil_commit`, if
`zl_suspend` is set, `zil_commit` will take a special branch of logic
and use `txg_wait_synced` instead of performing the normal `zil_commit`
logic.
This call to `txg_wait_synced` might be good enough for the data to
reach disk safely before it returns, but it does not ensure that all
outstanding lwb's reach the `LWB_STATE_DONE` state before it returns.
This is because, if there's an lwb "stuck" in
`zil_commit_waiter_timeout`, waiting for it's lwb to timeout, it will
maintain a non-null value for it's `lwb_buf` field and thus `zil_sync`
will not free that lwb. Thus, even though the lwb's data is already on
disk, the lwb will be left lingering, waiting on the CV, and will
eventually timeout and be issued to disk even though the write is
unnesseary.
So, after `zil_commit` is called from `zil_suspend`, we incorrectly
assume that there are not outstanding lwb's, and proceed to free all
lwb's found on the zilog's lwb list. As a result, we free the lwb that
will later be used `zil_commit_waiter_timeout`.
Reviewed by: John Kennedy <jwk404@gmail.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Prakash Surya <prakash.surya@delphix.com>
illumos/illumos-gate@cf07d3da99https://www.illumos.org/issues/8603:
To help make the ZIL's code more understandable, it was suggested that
the zilog_t's "zl_writer_lock" field should be renamed to "zl_issuer_lock".
Reviewed by: C Fraire <cfraire@me.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Prakash Surya <prakash.surya@delphix.com>
