Replace ZFS_ENTER and ZFS_VERIFY_ZP, which have hidden returns, with
functions that return error code. The reason we want to do this is
because hidden returns are not obvious and had caused some missing fail
path unwinding.
This patch changes the common, linux, and freebsd parts. Also fixes
fail path unwinding in zfs_fsync, zpl_fsync, zpl_xattr_{list,get,set}, and
zfs_lookup().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Closes#13831
I see a few issues in the issue tracker that might be aided by being
able to turn this on. We have no module parameter for it, so I would
like to add one.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13874
We pass sizeof (struct redact_record *) rather than sizeof (struct
redact_record). Passing the pointer size is wrong.
Coverity caught this in two places.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13885
The assertions are racy and the use of `membar_exit()` did nothing to
fix that.
The helpers use atomic functions, so we cleverly get values from the
atomics that we can use to ensure that the assertions operate on the
correct values.
We also use `membar_producer()` prior to decrementing reference counts
so that operations that happened prior to a decrement to 0 will be
guaranteed to happen before the decrement on architectures that reorder
atomics.
This also slightly improves performance by eliminating unnecessary
reads, although I doubt it would be measurable in any benchmark.
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13880
These were reported by Coverity as "Read from pointer after free" bugs.
Presumably, it did not report it as a use-after-free bug because it does
not understand the inline assembly that implements the atomic
instruction.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13881
When reviewing #13875, I noticed that our FreeBSD code has an issue
where it converts from `int64_t` to `int` when calling
`vnlru_free{,_vfsops}()`. The result is that if the int64_t is `1 <<
36`, the int will be 0, since the low bits are 0. Even when some low
bits are set, a value such as `((1 << 36) + 1)` would truncate to 1,
which is wrong.
There is protection against this on 32-bit platforms, but on 64-bit
platforms, there is no check to protect us, so we add a check.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13882
Coverity pointed out that if we somehow receive SPA_FEATURE_NONE, we
will use a negative number as an array index. A defensive assertion
seems appropriate.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13872
Coverity complains about a "use-after-free" bug in
`dbuf_prefetch_indirect_done()` because we use a pointer value after
freeing its buffer. The pointer is used for refcounting in ARC (as the
reference holder). There is a theoretical situation where the pointer
would be reused in a way that causes the refcounting to collide, so we
change the order in which we call arc_buf_destroy() and
dbuf_prefetch_fini() to match the rest of the function. This prevents
the theoretical situation from being a possibility.
Also, we have a few return statements with a value, despite this being a
void function. We clean those up while we are making changes here.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13869
We inherited membar_consumer() and membar_producer() from OpenSolaris,
but we had replaced membar_consumer() with Linux's smp_rmb() in
zfs_ioctl.c. The FreeBSD SPL consequently implemented a shim for the
Linux-only smp_rmb().
We reinstate membar_consumer() in platform independent code and fix the
FreeBSD SPL to implement membar_consumer() in a way analogous to Linux.
Reviewed-by: Konstantin Belousov <kib@FreeBSD.org>
Reviewed-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13843
Unused code detected by coverity.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13868
Coverity reported this as an out-of-bounds read.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13865
Coverty static analysis found these.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#10989Closes#13861
In our codebase, `cond_resched() and `schedule()` are Linux kernel
functions that have replaced the OpenSolaris `kpreempt()` functions in
the codebase to such an extent that `kpreempt()` in zfs_context.h was
broken. Nobody noticed because we did not actually use it. The header
had defined `kpreempt()` as `yield()`, which works on OpenSolaris and
Illumos where `sched_yield()` is a wrapper for `yield()`, but that does
not work on any other platform.
The FreeBSD platform specific code implemented shims for these, but the
shim for `schedule()` forced us to wait, which is different than merely
rescheduling to another thread as the original Linux code does, while
the shim for `cond_resched()` had the same definition as its kernel
kpreempt() shim.
After studying this, I have concluded that we should reintroduce the
kpreempt() function in platform independent code with the following
definitions:
- In the Linux kernel:
kpreempt(unused) -> cond_resched()
- In the FreeBSD kernel:
kpreempt(unused) -> kern_yield(PRI_USER)
- In userspace:
kpreempt(unused) -> sched_yield()
In userspace, nothing changes from this cleanup. In the kernels, the
function `fm_fini()` will now call `kern_yield(PRI_USER)` on FreeBSD and
`cond_resched()` on Linux. This is instead of `pause("schedule", 1)` on
FreeBSD and `schedule()` on Linux. This makes our behavior consistent
across platforms.
Note that Linux's SPL continues to use `cond_resched()` and
`schedule()`. However, those functions have been removed from both the
FreeBSD code and userspace code.
This should have the benefit of making it slightly easier to port the
code to new platforms by making how things should be mapped less
confusing.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13845
The function make_dev_s() was introduced to replace make_dev() in
FreeBSD 11.0. It allows further specification of properties and flags
and returns an error code on failure. Using this we can fail loading
the module more gracefully than a panic in situations such as when a
device named zfs already exists. We already use it for zvols.
Use make_dev_s() for /dev/zfs.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#13854
When iterating through children physical ashifts for vdev, prefer
ones above the maximum logical ashift, that we can actually use,
but within the administrator defined maximum.
When selecting top-level vdev ashift, do not set it to the defined
maximum in case physical ashift is even higher, but just ignore one.
Using the maximum does not prevent misaligned writes, but reduces
space efficiency. Since ZFS tries to write data sequentially and
aggregates the writes, in many cases large misanigned writes may be
not as bad as the space penalty otherwise.
Allow internal physical ashifts for vdevs higher than SHIFT_MAX.
May be one day allocator or aggregation could benefit from that.
Reduce zfs_vdev_max_auto_ashift default from 16 (64KB) to 14 (16KB),
so that ZFS may still use bigger ashifts up to SHIFT_MAX (64KB),
but only if it really has to or explicitly told to, but not as an
"optimization".
There are some read-intensive NVMe SSDs that report Preferred Write
Alignment of 64KB, and attempt to build RAIDZ2 of those leads to a
space inefficiency that can't be justified. Instead these changes
make ZFS fall back to logical ashift of 12 (4KB) by default and
only warn user that it may be suboptimal for performance.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#13798
The purpose of this PR is to accepts fadvise ioctl from userland
to do read-ahead by demand.
It could dramatically improve sequential read performance especially
when primarycache is set to metadata or zfs_prefetch_disable is 1.
If the file is mmaped, generic_fadvise is also called for page cache
read-ahead besides dmu_prefetch.
Only POSIX_FADV_WILLNEED and POSIX_FADV_SEQUENTIAL are supported in
this PR currently.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Finix Yan <yancw@info2soft.com>
Closes#13694
Upon inspection of our code, I noticed that we assume that
__alloc_percpu() cannot fail, and while it probably never has failed in
practice, technically, it can fail, so we should handle that.
Additionally, we incorrectly assume that `taskq_create()` in
spl_kmem_cache_init() cannot fail. The same remark applies to it.
Lastly, `spl-init()` failures should always return negative error
values, but in some places, we are returning positive 1, which is
incorrect. We change those values to their correct error codes.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13847
There's no VSX handler on FreeBSD for now.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Piotr Kubaj <pkubaj@FreeBSD.org>
Closes#13848
The only event hooked up is NOTE_ATTRIB, which is triggered when the
device is resized.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Rob Wing <rew@FreeBSD.org>
Closes#13773
This will be used to implement kqfilter support for zvol cdevs.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Rob Wing <rew@FreeBSD.org>
Closes#13773
This commit adds DD_FIELD string used in extensified dsl_dir zap object
for snapshots_changed property.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes#13819
Only the single snapshot rename is provided.
The recursive or more complex rename can be scripted.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Andriy Gapon <avg@FreeBSD.org>
Closes#13802
FreeBSD had a few platform-specific ARC tunables in the wrong place:
- Move FreeBSD-specifc ARC tunables into the same vfs.zfs.arc node as
the rest of the ARC tunables.
- Move the handlers from arc_os.c to sysctl_os.c and add compat sysctls
for the legacy names.
While here, some additional clean up:
- Most handlers are specific to a particular variable and don't need a
pointer passed through the args.
- Group blocks of related variables, handlers, and sysctl declarations
into logical sections.
- Match variable types for temporaries in handlers with the type of the
global variable.
- Remove leftover comments.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#13756
It makes sense to free memory in smaller chunks when approaching
arc_c_min to let other kernel subsystems to free more, since after
that point we can't free anything. This also matches behavior on
Linux, where to shrinker reported only the size above arc_c_min.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes#13794
The vfs_*_feature() macros turn anything that uses them into dead code,
so we can delete all of it.
As a side effect, zfs_set_fuid_feature() is now identical in
module/os/freebsd/zfs/zfs_vnops_os.c and
module/os/linux/zfs/zfs_vnops_os.c. A few other functions are identical
too. Future cleanup could move these into a common file.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13832
This reverts commit 80a650b7bb. This change
inadvertently introduced a regression in ztest where one of the new ASSERTs
is triggered in dsl_scan_visitbp().
Reviewed-by: George Amanakis <gamanakis@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #12275Closes#13799
Currently, snapshots_changed property is stored in dd_props_zapobj, due
to which the property is assumed to be local. This causes a difference
in behavior with respect to other readonly properties.
This commit stores the snapshots_changed property in dd_object. Source
is not set to local in this case, which makes it consistent with other
readonly properties.
This commit also updates the date string format to include seconds.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes#13785
When scrubbing an encrypted filesystem with unloaded key still report an
error in zpool status.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alek Pinchuk <apinchuk@axcient.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes#13675Closes#13717
There are a couple changes included here. The first is to introduce
a cap on the size the ZED will grow the zevent list to. One million
entries is more than enough for most use cases, and if you are
overflowing that value, the problem needs to be addressed another
way. The value is also tunable, for those who want the limit to be
higher or lower.
The other change is to add a kernel module parameter that allows
snapshot creation/deletion to be exempted from the history logging;
for most workloads, having these things logged is valuable, but for
some workloads it produces large quantities of log spam and isn't
especially helpful.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Issue #13374Closes#13753
Linux sets relatime on mount by default for any file system,
but relatime=off in ZFS disables it explicitly.
Let's be consistent with other file systems on Linux.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#13614
Thanks to George Wilson for clarifying this on Slack.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Christian Schwarz <christian.schwarz@nutanix.com>
Closes#13698
As of the Linux 5.20 kernel blk_cleanup_disk() has been removed,
all callers should use put_disk().
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#13728
As of the Linux 5.20 kernel bdevname() has been removed, all
callers should use snprintf() and the "%pg" format specifier.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#13728
This is a small cleanup for a trivial problem which happened to
be noticed while another issue was being investigated.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes#13730
Make dd_snap_cmtime property persistent across mount and unmount
operations by storing in ZAP and restore the value from ZAP on hold
into dd_snap_cmtime instead of updating it.
Expose dd_snap_cmtime as 'snapshots_changed' property that provides a
mechanism to quickly determine whether snapshot list for dataset has
changed without having to mount a dataset or iterate the snapshot list.
It specifies the time at which a snapshot for a dataset was last
created or deleted. This allows us to be more efficient how often we
query snapshots.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes#13635
A symlink to i386 includes is created in the build dir on amd64 since
freebsd/freebsd-src@d07600c563
Tell git to ignore it like the other include links.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#13719
The checksum benchmarking on module load may take a really long time
on embedded systems with a slow cpu. Avoid all benchmarks >= 1MiB on
systems, where EdonR is slower then 300 MiB/s.
This limit is currently hardcoded via the define LIMIT_PERF_MBS.
This is the new benchmark output of a slow Intel Atom:
```
implementation 1k 4k 16k 64k 256k 1m 4m 16m
edonr-generic 209 257 268 259 262 0 0 0
skein-generic 129 150 151 150 150 0 0 0
sha256-generic 50 55 56 56 56 0 0 0
sha512-generic 76 86 88 89 88 0 0 0
blake3-generic 63 62 62 62 61 0 0 0
blake3-sse2 114 292 301 307 309 0 0 0
```
Reviewed-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes#13695
This type of recv is used to heal corrupted data when a replica
of the data already exists (in the form of a send file for example).
With the provided send stream, corrective receive will read from
disk blocks described by the WRITE records. When any of the reads
come back with ECKSUM we use the data from the corresponding WRITE
record to rewrite the corrupted block.
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Zuchowski <pzuchowski@datto.com>
Signed-off-by: Alek Pinchuk <apinchuk@axcient.com>
Closes#9372
The file module/os/freebsd/zfs/zfs_ioctl_compat.c fails compiling
because of this error: 'static' is not at beginning of declaration
This commit fixes the three places within that file.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes#13702
- When iterating snapshots with name only, e.g., "-o name -s name",
libzfs uses simple snapshot iterator and results are displayed
in alphabetic order. This PR adds support for faster version of
createtxg sort by avoiding nvlist parsing for properties. Flags
"-o name -s createtxg" will enable createtxg sort while using
simple snapshot iterator.
- Added support to read createtxg property directly from zfs handle
for filesystem, volume and snapshot types instead of parsing nvlist.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#13577
ZIL kstats are reported in an inclusive way, i.e., same counters are
shared to capture all the activities happening in zil. Added support
to report zil stats for every datset individually by combining them
with already exposed dataset kstats.
Wmsum uses per cpu counters and provide less overhead as compared
to atomic operations. Updated zil kstats to replace wmsum counters
to avoid atomic operations.
Reviewed-by: Christian Schwarz <christian.schwarz@nutanix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#13636
It may happen that scan bookmark points to a block that was turned
into a part of a big hole. In such case dsl_scan_visitbp() may skip
it and dsl_scan_check_resume() will not be called for it. As result
new scan suspend won't be possible until the end of the object, that
may take hours if the object is a multi-terabyte ZVOL on a slow HDD
pool, stretching TXG to all that time, creating all sorts of problems.
This patch changes the resume condition to any greater or equal block,
so even if we miss the bookmarked block, the next one we find will
delete the bookmark, allowing new suspend.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#13643
Allocation via kmem_cache_alloc() is limited to less then 4m for
some architectures.
This commit limits the benchmarks with the linear abd cache to 1m
on all architectures and adds 4m + 16m benchmarks via non-linear
abd_alloc().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Co-authored-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes#13669Closes#13670
Makes the case sensitivity setting visible on Linux in /proc/mounts.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#13607
Specify the lua and zstd license text in the manor in which the
kernel MODULE_LICENSE macro requires it. The now duplicate entries
were merged and a comment added to make it clear what they apply to.
Reviewed-by: Christian Schwarz <christian.schwarz@nutanix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#13641
Fixes a small kernel memory leak which would occur if a pool failed
to import because the `DMU_POOL_VDEV_ZAP_MAP` key can't be read from
a presumably damaged MOS config. In the case of a missing key there
was no leak.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Finix1979 <yancw@info2soft.com>
Closes#13629
Before this change for every valid parity column raidz_parity_verify()
allocated new buffer and copied there existing data, then recalculated
the parity and compared the result with the copy. This patch removes
the memory copy, simply swapping original buffer pointers with newly
allocated empty ones for parity recalculation and comparison. Original
buffers with potentially incorrect parity data are then just freed,
while new recalculated ones are used for repair.
On a pool of 12 4-wide raidz vdevs, storing 1.5TB of 16MB blocks, this
change reduces memory traffic during scrub by 17% and total unhalted
CPU time by 25%.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#13613
Issuing several scrub reads for a block we may use the parent ZIO
buffer for one of child ZIOs. If that read complete successfully,
then we won't need to copy the data explicitly. If block has only
one copy (typical for root vdev, which is also a mirror inside),
then we never need to copy -- succeed or fail as-is. Previous
code also copied data from buffer of every successfully completed
child ZIO, but that just does not make any sense.
On healthy N-wide mirror this saves all N+1 (or even more in case
of ditto blocks) memory copies for each scrubbed block, allowing
CPU to focus mostly on check-summing. For other vdev types it
should save one memory copy per block copy at root vdev.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#13606
