When an invalid incremental send is requested where the "to" ds is
before the "from" ds, make sure to drop the reference to the pool
and the dataset before returning the error.
Add an assert on FreeBSD to make sure we don't hold any locks after
returning from an ioctl.
Add some test coverage.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10919
Address some unused value and control flow issues flagged by Coverity.
Unreachable code is pruned and unused values are avoided.
Some scattered sections are reordered for coherence.
We can assume kmem_alloc(n, KM_SLEEP) doesn't fail, so there is no need
to check if it returned NULL. The allocated memory doesn't need to be
zeroed, other than the last iovec (the MAC).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10884
The procfs_list interface is required by several kstats. Implement
this functionality for FreeBSD to provide access to these kstats.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10890
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10899
In commit cd32b4f5b7 ("Fix a deadlock in the FreeBSD getpages VOP") I
introduced a bug while porting the patch originally committed to
FreeBSD: the rangelock pointer may be NULL if the try operation failed,
so we must avoid calling zfs_rangelock_unlock() in that case.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reported-by: Steve Wills <swills@FreeBSD.org>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#10519Closes#10960
Without this, the sysctl system calls will acquire a global lock before
invoking the handler. This is noticeable in some situations when
running top(1). The global lock is mostly vestigal but continues to see
some use and so contention is still a problem; until the default sense
of the MPSAFE flag changes, we have to annotate each and every handler.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#10836
This is in preparation for some functional changes.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#10950
== Motivation and Context
The new vdev ashift optimization prevents the removal of devices when
a zfs configuration is comprised of disks which have different logical
and physical block sizes. This is caused because we set 'spa_min_ashift'
in vdev_open and then later call 'vdev_ashift_optimize'. This would
result in an inconsistency between spa's ashift calculations and that
of the top-level vdev.
In addition, the optimization logical ignores the overridden ashift
value that would be provided by '-o ashift=<val>'.
== Description
This change reworks the vdev ashift optimization so that it's only
set the first time the device is configured. It still allows the
physical and logical ahsift values to be set every time the device
is opened but those values are only consulted on first open.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Cedric Berger <cedric@precidata.com>
Signed-off-by: George Wilson <gwilson@delphix.com>
External-Issue: DLPX-71831
Closes#10932
https://reviews.freebsd.org/D26346
Do not copy vp into f_data for DTYPE_VNODE files. The vnode pointer is
already stored in f_vnode. Use that so f_data can be reused.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10929
The lock is taken all the time and as a regular read-write lock
avoidably serves as a mount point-wide contention point.
This forward ports FreeBSD revision r357322.
To quote aforementioned commit:
Sample result doing an incremental -j 40 build:
before: 173.30s user 458.97s system 2595% cpu 24.358 total
after: 168.58s user 254.92s system 2211% cpu 19.147 total
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#10896
We only need the kernel interfaces in crypto, not the device node in
cryptodev.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10901
Added comments in following files
with links to Illumos manual pages:
./module/avl/avl.c
./module/nvpair/nvpair.c
./module/os/linux/spl/spl-kstat.c
./module/os/freebsd/spl/spl_kstat.c
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Spencer Kinny <spencerkinny1995@gmail.com>
Closes#5113Closes#10859
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Toomas Soome <tsoome@me.com>
Closes#10867
Moving spa_stats added the additional burden of supporting
KSTAT_TYPE_IO.
spa_state_addr will always return a valid value regardless of
the value of 'n'. On FreeBSD this will cause an infinite loop
as it relies on the raw ops addr routine to indicate that there
is no more data.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10860
SECLABEL is undefined on FreeBSD and should be pruned.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#10847
FreeBSD's previous ZFS implemented INGLOBALZONE(thread) as
(!jailed((thread)->td_ucred)) and passed curthread to INGLOBALZONE.
We pass curproc instead of curthread, so we can achieve the same effect
with (!jailed((proc)->p_ucred)). The implementation is trivial enough
to fit on a single line in a define. We don't really need a whole
separate function for something that's already macros all the way down.
Eliminate in_globalzone.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#10851
Initially it was considered simplest to stub out all
of the functions on FreeBSD. Now that FreeBSD supports
KSTAT_TYPE_RAW at least some of the functionality should
be made available.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10842
In zvol_geom_open on first open we need to guarantee
that the namespace lock is held to avoid spurious
failures in zvol_first_open.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10841
A few kstats use KSTAT_TYPE_RAW to provide a string generated on
demand. Implementing these as sysctls was punted until now.
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10836
The #pragma ident is a historical relic and not needed any more, this
pragma is actually unknown for common compilers and is only causing
trouble.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Toomas Soome <tsoome@me.com>
Closes#10810
In absence of inheriting entry for owner@, group@, or everyone@,
zfs_acl_chmod() is called to set these. This can cause confusion for Samba
admins who do not expect these entries to appear on newly created files and
directories once they have been stripped from from the parent directory.
When aclmode is set to "restricted", chmod is prevented on non-trivial ACLs.
It is not a stretch to assume that in this case the administrator does not want
ZFS to add the missing special entries. Add check for this aclmode, and if an
inherited entry is present skip zfs_acl_chmod().
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andrew Walker <awalker@ixsystems.com>
Closes#10748
Many modern devices use physical allocation units that are much
larger than the minimum logical allocation size accessible by
external commands. Two prevalent examples of this are 512e disk
drives (512b logical sector, 4K physical sector) and flash devices
(512b logical sector, 4K or larger allocation block size, and 128k
or larger erase block size). Operations that modify less than the
physical sector size result in a costly read-modify-write or garbage
collection sequence on these devices.
Simply exporting the true physical sector of the device to ZFS would
yield optimal performance, but has two serious drawbacks:
1. Existing pools created with devices that have different logical
and physical block sizes, but were configured to use the logical
block size (e.g. because the OS version used for pool construction
reported the logical block size instead of the physical block
size) will suddenly find that the vdev allocation size has
increased. This can be easily tolerated for active members of
the array, but ZFS would prevent replacement of a vdev with
another identical device because it now appears that the smaller
allocation size required by the pool is not supported by the new
device.
2. The device's physical block size may be too large to be supported
by ZFS. The optimal allocation size for the vdev may be quite
large. For example, a RAID controller may export a vdev that
requires read-modify-write cycles unless accessed using 64k
aligned/sized requests. ZFS currently has an 8k minimum block
size limit.
Reporting both the logical and physical allocation sizes for vdevs
solves these problems. A device may be used so long as the logical
block size is compatible with the configuration. By comparing the
logical and physical block sizes, new configurations can be optimized
and administrators can be notified of any existing pools that are
sub-optimal.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Matthew Macy <mmacy@freebsd.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10619
This option is used by FreeBSD boot loader.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mariusz Zaborski <oshogbo@vexillium.org>
Closes#10738
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10727
We limit the size of nvlists passed to the kernel so a user cannot make
the kernel do an unreasonably large allocation. On FreeBSD this limit
was 128 kiB, which turns out to be a bit too small when doing some
operations involving a large number of datasets or snapshots, for
example replication.
Make this limit tunable, with a platform-specific auto default.
Linux keeps its limit at KMALLOC_MAX_SIZE. FreeBSD uses 1/4 of the
system limit on user wired memory, which allows it to scale depending
on system configuration.
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Issue #6572Closes#10706
The ARC caches data in scatter ABD's, which are collections of pages,
which are typically 4K. Therefore, the space used to cache each block
is rounded up to a multiple of 4K. The ABD subsystem tracks this wasted
memory in the `scatter_chunk_waste` kstat. However, the ARC's `size` is
not aware of the memory used by this round-up, it only accounts for the
size that it requested from the ABD subsystem.
Therefore, the ARC is effectively using more memory than it is aware of,
due to the `scatter_chunk_waste`. This impacts observability, e.g.
`arcstat` will show that the ARC is using less memory than it
effectively is. It also impacts how the ARC responds to memory
pressure. As the amount of `scatter_chunk_waste` changes, it appears to
the ARC as memory pressure, so it needs to resize `arc_c`.
If the sector size (`1<<ashift`) is the same as the page size (or
larger), there won't be any waste. If the (compressed) block size is
relatively large compared to the page size, the amount of
`scatter_chunk_waste` will be small, so the problematic effects are
minimal.
However, if using 512B sectors (`ashift=9`), and the (compressed) block
size is small (e.g. `compression=on` with the default `volblocksize=8k`
or a decreased `recordsize`), the amount of `scatter_chunk_waste` can be
very large. On a production system, with `arc_size` at a constant 50%
of memory, `scatter_chunk_waste` has been been observed to be 10-30% of
memory.
This commit adds `scatter_chunk_waste` to `arc_size`, and adds a new
`waste` field to `arcstat`. As a result, the ARC's memory usage is more
observable, and `arc_c` does not need to be adjusted as frequently.
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10701
Stepping stone toward re-enabling spa_thread on FreeBSD.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10715
Linux and FreeBSD will most likely never see this issue.
On macOS when kext is unloaded, but zed is still connected, zed
will be issued ENODEV. As the cdevsw is released, the kernel
will not have zfsdev_release() called to release minor/onexit/events,
and it "leaks". This ensures it is cleaned up before unload.
Changed the for loop from zsprev, to zsnext style, for less
code duplication.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Jorgen Lundman <lundman@lundman.net>
Closes#10700
This was previously moved because nothing else in-tree uses it, but
evidently DilOS uses it out of tree.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Ryan Moeller <freqlabs@freebsd.org>
Closes#10361Closes#10685
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10682
Remove dead code to make the implementation easier to understand.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes#10650
Remove dead code to make the implementation easier to understand.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes#10650
Must acquire the z_teardown_lock before accessing the zfsvfs_t object.
I can't reproduce this panic on demand, but this looks like the
correct solution.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Authored-by: asomers <asomers@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10656
A collection of header changes to enable FreeBSD to build
with vendored OpenZFS.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10635
Change some comments copied from the Linux code to describe
the appropriate methods on FreeBSD.
Convert some tunables to ZFS_MODULE_PARAM so they get created
on FreeBSD.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10647
The ARC shrinker callback `arc_shrinker_count/_scan()` is invoked by the
kernel's shrinker mechanism when the system is running low on free
pages. This happens via 2 code paths:
1. "direct reclaim": The system is attempting to allocate a page, but we
are low on memory. The ARC shrinker callback is invoked from the
page-allocation code path.
2. "indirect reclaim": kswapd notices that there aren't many free pages,
so it invokes the ARC shrinker callback.
In both cases, the kernel's shrinker code requests that the ARC shrinker
callback release some of its cache, and then it measures how many pages
were released. However, it's measurement of released pages does not
include pages that are freed via `__free_pages()`, which is how the ARC
releases memory (via `abd_free_chunks()`). Rather, the kernel shrinker
code is looking for pages to be placed on the lists of reclaimable pages
(which is separate from actually-free pages).
Because the kernel shrinker code doesn't detect that the ARC has
released pages, it may call the ARC shrinker callback many times,
resulting in the ARC "collapsing" down to `arc_c_min`. This has several
negative impacts:
1. ZFS doesn't use RAM to cache data effectively.
2. In the direct reclaim case, a single page allocation may wait a long
time (e.g. more than a minute) while we evict the entire ARC.
3. Even with the improvements made in 67c0f0dedc ("ARC shrinking blocks
reads/writes"), occasionally `arc_size` may stay above `arc_c` for the
entire time of the ARC collapse, thus blocking ZFS read/write operations
in `arc_get_data_impl()`.
To address these issues, this commit limits the ways that the ARC
shrinker callback can be used by the kernel shrinker code, and mitigates
the impact of arc_is_overflowing() on ZFS read/write operations.
With this commit:
1. We limit the amount of data that can be reclaimed from the ARC via
the "direct reclaim" shrinker. This limits the amount of time it takes
to allocate a single page.
2. We do not allow the ARC to shrink via kswapd (indirect reclaim).
Instead we rely on `arc_evict_zthr` to monitor free memory and reduce
the ARC target size to keep sufficient free memory in the system. Note
that we can't simply rely on limiting the amount that we reclaim at once
(as for the direct reclaim case), because kswapd's "boosted" logic can
invoke the callback an unlimited number of times (see
`balance_pgdat()`).
3. When `arc_is_overflowing()` and we want to allocate memory,
`arc_get_data_impl()` will wait only for a multiple of the requested
amount of data to be evicted, rather than waiting for the ARC to no
longer be overflowing. This allows ZFS reads/writes to make progress
even while the ARC is overflowing, while also ensuring that the eviction
thread makes progress towards reducing the total amount of memory used
by the ARC.
4. The amount of memory that the ARC always tries to keep free for the
rest of the system, `arc_sys_free` is increased.
5. Now that the shrinker callback is able to provide feedback to the
kernel's shrinker code about our progress, we can safely enable
the kswapd hook. This will allow the arc to receive notifications
when memory pressure is first detected by the kernel. We also
re-enable the appropriate kstats to track these callbacks.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: George Wilson <george.wilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10600
Renamed to avoid conflicting with refcount.h when a different
implementation is already provided by the platform.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10620
This is a step toward being able to vendor the OpenZFS code in FreeBSD.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10625
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10623
i386 has some additional memory reservation logic that limits the size
of the reported available memory. This was accidentally being used on
all arches due to a missing header.
Include machine/vmparam.h in freebsd/zfs/arc_os.c to pull in the
missing UMA_MD_SMALL_ALLOC definition.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10616
This is only used for the kstat, but something other than 0 is nice.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10626
Drop unnecessary redefinition's of several arcstat values.
Put missing extern declaration of arc_no_grow_shift in arc_impl.h.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10609
The process of evicting data from the ARC is referred to as
`arc_adjust`.
This commit changes the term to `arc_evict`, which is more specific.
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10592
These tunables were renamed from vfs.zfs.arc_min and
vfs.zfs.arc_max to vfs.zfs.arc.min and vfs.zfs.arc.max.
Add legacy compat tunables for the old names.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10579
Update the zfs commands such that they're backwards compatible with
the version of ZFS is the base FreeBSD.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10542
On linux the list debug code has been setting off a failure when
checking that the node->next->prev value is pointing back at the node.
At times this check evaluates to 0xdead. When removing a child from a
gang ABD we must acquire the child's abd_mtx to make sure that the
same ABD is not being added to another gang ABD while it is being
removed from a gang ABD. This fixes a race condition when checking
if an ABDs link is already active and part of another gang ABD before
adding it to a gang.
Added additional debug code for the gang ABD in abd_verify() to make
sure each child ABD has active links. Also check to make sure another
gang ABD is not added to a gang ABD.
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#10511
The filesystem_limit and snapshot_limit properties limit the number of
filesystems or snapshots that can be created below this dataset.
According to the manpage, "The limit is not enforced if the user is
allowed to change the limit." Two types of users are allowed to change
the limit:
1. Those that have been delegated the `filesystem_limit` or
`snapshot_limit` permission, e.g. with
`zfs allow USER filesystem_limit DATASET`. This works properly.
2. A user with elevated system privileges (e.g. root). This does not
work - the root user will incorrectly get an error when trying to create
a snapshot/filesystem, if it exceeds the `_limit` property.
The problem is that `priv_policy_ns()` does not work if the `cred_t` is
not that of the current process. This happens when
`dsl_enforce_ds_ss_limits()` is called in syncing context (as part of a
sync task's check func) to determine the permissions of the
corresponding user process.
This commit fixes the issue by passing the `task_struct` (typedef'ed as
a `proc_t`) to syncing context, and then using `has_capability()` to
determine if that process is privileged. Note that we still need to
pass the `cred_t` to syncing context so that we can check if the user
was delegated this permission with `zfs allow`.
This problem only impacts Linux. Wrappers are added to FreeBSD but it
continues to use `priv_check_cred()`, which works on arbitrary `cred_t`.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#8226Closes#10545
