The check introduced by r285946 failed to add the dependency on
opt_kstack_pages.h which meant the default value for the platform instead
of the customised options KSTACK_PAGES=X was being tested.
Also wrap in #ifdef __FreeBSD__ for portability.
MFC after: 3 days
Sponsored by: Multiplay
When a process is exiting, there is a narrow window where p_cred may be
NULL while its threads are still executing. Specifically, the last thread
to exit a process sets the process state to PRS_ZOMBIE with the proc
spinlock held and then calls thread_exit(). thread_exit() drops the spin
lock, permitting the process to be reaped and thus causing its cred struct
to be released. However, the exiting thread may still cause DTrace probes
to fire by calling sched_throw(), resulting in a double fault if such a
probe enabling attempts to access the GID or UID DIF variables.
The thread's cred reference is not susceptible to this race since it is not
released until after the thread has exited.
MFC after: 1 week
As ZFS requires a more kernel stack pages than is the default on some
architectures e.g. i386, warn if KSTACK_PAGES is less than
ZFS_MIN_KSTACK_PAGES (which is 4 at the time of writing).
MFC after: 3 days
Sponsored by: Multiplay
This change refactors the existing create_thread() function to be more
generic. It replaces almost all of its arguments by a callback that can
be used to extract the thread ID and copy it out to the right place, but
also to perform additional initialization steps, such as setting the
trapframe. This also makes the difference between thr_new() and
thr_create() more clear in my opinion.
This function is going to be used by the CloudABI compatibility layer.
It looks like the OpenSolaris compatibility framework already provides a
function called thread_create(). Rename this function to
do_thread_create() and use a macro to deal with the namespacing
conflict. A similar approach is already used for thread_exit().
MFC after: 1 month
in lockstat.ko. This means that lockstat probes now have typed arguments and
will utilize SDT probe hot-patching support when it arrives.
Reviewed by: gnn
Differential Revision: https://reviews.freebsd.org/D2993
enabled. The cost of a timecounter read can be quite significant, and the
problem became more apparent after r284297, since that change resulted in
a call to lockstat_nsecs() for each acquisition of an rwlock read lock.
PR: 201642
Reviewed by: avg
Tested by: Jason Unovitch
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D3073
belongs to the kernel stack address range for the thread. Right now,
code checks that new frame is not farther then KSTACK_PAGES pages from
the current frame, which allows the address to point past the top of
the stack.
Reviewed by: andrew, emaste, markj
Differential revision: https://reviews.freebsd.org/D3108
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Transitions 0->1 and 1->0 (which decide e.g. on putting the vnode on the free
list) of either counter are still guarded with vnode interlock.
Reviewed by: kib (earlier version)
Tested by: pho
Previously several places were doing it on its own, partially
incorrectly (e.g. without the filedesc locked) or even actively harmful
by populating jdir or assigning rootvnode without vrefing it.
Reviewed by: kib
macros on amd64 and i386. Move the definition to machine/param.h.
kgdb defines INKERNEL() too, the conflict is resolved by renaming kgdb
version to PINKERNEL().
On i386, correct the lowest kernel address. After the shared page was
introduced, USRSTACK no longer points to the last user address + 1 [*]
Submitted by: Oliver Pinter [*]
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
We now take z_teardown_lock as a writer to ensure that there is no I/O
while the filesystem state is in a flux. Also, zfs_suspend_fs() ->
zfsvfs_teardown() call zfs_unregister_callbacks() and zfs_resume_fs() ->
zfsvfs_setup() call zfs_unregister_callbacks(). Previously there was no
synchronization between those calls and the calls in the re-mounting
case. That could lead to concurrent execution and a crash.
PR: 180060
Differential Revision: https://reviews.freebsd.org/D2865
Suggested by: mahrens
Reviewed by: delphij, pho, mahrens, will
MFC after: 13 days
Sponsored by: ClusterHQ
Reviewed by: Bayard Bell <buffer.g.overflow@gmail.com>
Reviewed by: Alek Pinchuk <alek@nexenta.com>
Reviewed by: Simon Klinkert <simon.klinkert@gmail.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: Matthew Ahrens <mahrens@delphix.com>
illumos/illumos-gate@46e1baa6cfhttps://www.illumos.org/issues/5911
Sometimes ZFS appears to hang while deleting a file. It is actually
making slow progress at the file deletion, but other operations
(administrative and writes via the data path) "hang" until the file
removal completes, which can take a long time if the file has many
blocks. The deletion (or most of it) happens in a single txg, and the
sync thread spends most of its time reading indirect blocks via this
stack trace:
swtch+0x141()
cv_wait+0x70()
zio_wait+0x5b()
dbuf_read+0x2c0()
free_children+0x50()
free_children+0x12a()
free_children+0x12a()
free_children+0x12a()
dnode_sync_free_range_impl+0xdf()
dnode_sync_free_range+0x52()
range_tree_vacate+0x65()
dnode_sync+0x1d8()
dmu_objset_sync_dnodes+0x77()
dmu_objset_sync+0x19f()
dsl_dataset_sync+0x51()
dsl_pool_sync+0x9a()
spa_sync+0x2ff()
txg_sync_thread+0x21f()
thread_start+8()
One way to reproduce the problem is if we are over the arc_meta_limit,
e.g. because lots of indirect blocks are pinned because we have L0
dbufs under them. It could be that most of the L1 indirects are cached,
in which case when dmu_free_long_range_impl() calls dmu_tx_hold_free(),
it will complete very quickly. This allows dmu_free_long_range_impl() to
put many (perhaps all of its) transactions in the same TXG. However,
dmu_free_long_range_impl() calls dnode_evict_dbufs (and
dnode_free_range()), which removes the L0 dbufs, thus reducing the hold
count on the L1 indirect blocks above it, allowing them to be evicted.
Because we are over the arc_meta_limit(), these L1 blocks will be
evicted ASAP. Thus when we get to syncing context, the L1 indirects are
no longer cached and must be read in.
Obtained from: illumos
MFC after: 15 days
Do that only when when fast inline versions are available.
At the moment that can be the case only in the kernel and not for all
platforms.
The original code uses the binary search and that's kept as a fallback.
This is a micro optimization.
Differential Revision: https://reviews.freebsd.org/D2839
Reviewed by: delphij, mahrens, mav
MFC after: 17 days
o Provide an extensive set of assertions for input array of pages.
o Remove now duplicate assertions from different pagers.
Sponsored by: Nginx, Inc.
Sponsored by: Netflix
The problem is that when inline versions of flsl and flsll are not
available, then libkern.h must be included for their declarations
in kernel sources.
The fix would be trivial, but I would like to figure out first if
it even makes sense to use the libkern provided implementations.
Reported by: bz
Pointyhat to: avg
b_size is a logical size of a buffer in memory, b_asize is its physical
size that accounts for possible compression.
Currently the latter is the best approximation for the allocated, on-disk
size.
L2ARC TRIM support was committed a few weeks before L2ARC compression
was imported, so originally the code was correct, because b_size was
the size.
Further thoughts. Given that the cache device is being overwritten
in a circular fashion it is not clear if a TRIM per each evicted L2ARC
buffer has any benefits.
Maybe it would be sufficient to issue a single trim request for the whole
device when it is loaded, e.g. after a bootup, or when it is unloaded, e.g.
before a shutdown. At least as long as L2ARC is not persistent across
reboots.
Discussed with: smh
MFC after: 19 says
This is a micro optimization.
The upstream code uses the binary search.
Differential Revision: https://reviews.freebsd.org/D2839
Reviewed by: delphij, mav
MFC after: 15 days
5946 zfs_ioc_space_snaps must check that firstsnap and lastsnap refer to snapshots
5945 zfs_ioc_send_space must ensure that fromsnap refers to a snapshot
Reviewed by: Steven Hartland <killing@multiplay.co.uk>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gordon.ross@nexenta.com>
illumos/illumos-gate@24218bebb4
Note that the upstream commit is modified during MFV: in the upstream
the check is done by inspecting ds_is_snapshot field while in FreeBSD
we call dsl_dataset_is_snapshot().
This is because illumos/illumos-gate@bc9014e6a8
(r277428 in vendor-sys/illumos) is not MFV-ed yet.
MFC after: 10 days
Currently there is no good reason to mangle the userland API.
The change was introduced in eac1d566b4,
r279437. Also see https://reviews.freebsd.org/D1881.
I am still convinced that nv should not have introduced intentionally
conflicting API.
Discussed with: rstone
X-MFC with: r279437
Sponsored by: ClusterHQ
Nothing stops a parallel unmount to suceed before the given call to
dounmount() checks and locks the covered vnode. Prevent dounmount()
from acting on the freed (although type-stable) memory by changing the
interface to require the mount point to be referenced. dounmount()
consumes the reference on return, regardless of the sucessfull or
erronous result.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
- this should fail early unless the force flag is set
- if the force flag is set then any local modifications including
snapshots should be undone
See: https://www.illumos.org/issues/5912
See: https://reviews.csiden.org/r/220/
Reviewed by: mahrens, Paul Dagnelie <pcd@delphix.com>
MFC after: 15 days
Sponsored by: ClusterHQ
years for head. However, it is continuously misused as the mpsafe argument
for callout_init(9). Deprecate the flag and clean up callout_init() calls
to make them more consistent.
Differential Revision: https://reviews.freebsd.org/D2613
Reviewed by: jhb
MFC after: 2 weeks
This allows to ensure that we do not write to a file that was opened
for reading only or vice versa.
Also, use the correct capability in in zfs_ioc_send_new().
Differential Revision: https://reviews.freebsd.org/D2382
Reviewed by: delphij
MFC after: 17 days
Sponsored by: ClusterHQ
At present zfs_domount() acquires a reference on the filesystem's root vnode
and that reference is kept until zfs_umount.
The latter calls vflush(rootrefs = 1) to dispose of the extra reference.
There is no explanation of why that reference is kept - what problem it
solves or what behavior it improves.
Also, that logic is FreeBSD specific.
There is one real problem with that reference, though.
zfs recv -F may receive a full, non-incremental stream to a mounted filesystem.
In that case the received root object is likely to have a different z_gen
attribute value. Because of that, zfs_rezget will leave the previous root znode
and vnode disassociated from the actual object (z_sa_hdl == NULL).
Thus, future calls to VFS_ROOT() -> zfs_root() will produce a new vnode-znode
pair, while the old one will be kept alive by the outstanding reference.
So, the outstanding reference will not actually be for the new root vnode
(or, more precisely, vnodes - because a root vnode may be recycled and a newer
one can be created).
As a result, when vflush(rootrefs = 1) s called there will be two problems:
- a leaked reference on the old root vnode preventing a graceful unmount
- insufficient references on the actual root vnode leading to a crash upon
access to the vnode after it is destroyed by vgone() + vdrop()
The second issue will actually override the first one.
Differential Revision: https://reviews.freebsd.org/D2353
Reviewed by: delphij, kib, smh
MFC after: 17 days
In traverse_visitbp(), the input argument dnp is modified in the middle
to point to a temporary buffer. Originally this doesn't matter, because
no user of TRAVERSE_POST dereferences it. However, in fbeddd6 a piece of
code is added dereferencing dnp after the modification, creating a possible
bug.
We fix this by creating a new local variable cdnp for the DMU_OT_DNODE case,
so we don't modify the input argument. Also we introduce different local
variables in the DMU_OT_OBJSET case to prevent confusion between the input
argument.
Obtained from: zfsonlinux (a585f2f844ed3d4270221fed88f5e494eb55d932)
MFC after: 2 weeks
Sponsored by: Multiplay
The old comment in zfs_rezget explains what situation the code handles,
the new comment also describes how the situation can arise.
Also, re-join a line that became sufficiently shorti some time ago.
Differential Revision: https://reviews.freebsd.org/D2352
Reviewed by: delphij, smh
MFC after: 12 days
/dev/zfs always has per-open data, so when it is missing the file
descriptor is for some other file. Returning ENOENT in this case
is confusing as a variety of other conditions (like a missing dataset)
may result in the same error. It's better to consistently return
EBADF for any problems with the file descriptor.
Note that zfs_onexit_fd_hold() is used with 'automatic cleanup fd'
- when that fd is closed, typically because a process is terminated,
some cleanup action is taken by ZFS driver. E.g. a temporary
snapshot hold is released.
Perhaps, it would even be worthwhile changing devfs_get_cdevpriv()
to return EBADF if there is no associated data.
Differential Revision: https://reviews.freebsd.org/D2370
Reviewed by: delphij, smh
MFC after: 12 days
