This compatibility code is no longer needed. For it a while
iov_iter_init_compat() was used by zfs_uio_prefaultpages() but
this code should have been dropped as part of commit 83b91ae1.
Take care of that oversight and remove it.
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11543
ABD's currently track their parent/child relationship. This applies to
`abd_get_offset()` and `abd_borrow_buf()`. However, nothing depends on
knowing this relationship, it's only used for consistency checks to
verify that we are not destroying an ABD that's still in use. When we
are creating/destroying ABD's frequently, the performance impact of
maintaining these data structures (in particular the atomic
increment/decrement operations) can be measurable.
This commit removes this verification code on production builds, but
keeps it when ZFS_DEBUG is set.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#11535
In ZED zfs_retire agent added a check to handle Distributed Spare
replacement for Faulted VDEV also.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Vipin Kumar Verma <vipin.verma@hpe.com>
Signed-off-by: Mark Maybee <mark.maybee@hpe.com>
Closes#11354Closes#11355
I originally applied a fix in #11539 to fix a parent's child references
when a gang ABD is free'd. However, I did not take into account
abd_gang_add_gang(). We still need to make sure to update the child
references in this function as well. In order to resolve this I removed
decreasing the gang ABD's size in abd_free_gang() as well as moved back
the original placeent of zfs_refcount_remove_many() in abd_free().
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#11542
All tests need to be included in the Makefiles.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#11541
`__vdev_disk_physio()` uses `abd_nr_pages_off()` to allocate a bio with
a sufficient number of iovec's to process this zio (i.e.
`nr_iovecs`/`bi_max_vecs`). If there are not enough iovec's in the bio,
then additional bio's will be allocated. However, this is a sub-optimal
code path. In particular, it requires several abd calls (to
`abd_nr_pages_off()` and `abd_bio_map_off()`) which will have to walk
the constituents of the ABD (the pages or the gang children) because
they are looking for offsets > 0.
For gang ABD's, `abd_nr_pages_off()` returns the number of iovec's
needed for the first constituent, rather than the sum of all
constituents (within the requested range). This always under-estimates
the required number of iovec's, which causes us to always need several
bio's. The end result is that `__vdev_disk_physio()` is usually O(n^2)
for gang ABD's (and occasionally O(n^3), when more than 16 bio's are
needed).
This commit fixes `abd_nr_pages_off()`'s handling of gang ABD's, to
correctly determine how many iovec's are needed, by adding up the number
of iovec's for each of the gang children in the requested range.
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#11536
If we do not write any buffers to the cache device and the evict hand
has not advanced do not update the cache device header.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes#11522Closes#11537
Moving the call to zfs_refcount_remove_many() in abd_free() to be called
before any of the ABD free variants are called. This is necessary
because abd_free_gang() adjusts the abd_size for the gang ABD. If the
parent's child references are removed after free'ing the gang ABD the
refcount is not adjusted correctly for the parent's children.
I also removed some stray abd_put() in comments and changed
abd_free_gang_abd() -> abd_free_gang().
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#11539
While you can use zdb -R poolname vdev:offset:[<lsize>/]<psize>[:flags]
to extract individual DVAs from a vdev, it would be handy for be able
copy an entire file out of the pool.
Given a file or object number, add support to copy the contents to a
file. Useful for debugging and recovery.
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#11027
Before a hash table was added on top of the nvlist code, there were
cases where the nvlist allocation was changed from fnvlist_alloc()
to nvlist_alloc() to avoid expensive NV_UNIQUE_NAME checks. Now
this is no longer necessary. These changes should be reverted to be
consistent with other code. There are some cases where this change
will also reduce the number of iterations.
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mark Maybee <mark.maybee@delphix.com>
Closes#11464
There is a race condition in zfs_zrele_async when we are checking if
we would be the one to evict an inode. This can lead to a txg sync
deadlock.
Instead of calling into iput directly, we attempt to perform the atomic
decrement ourselves, unless that would set the i_count value to zero.
In that case, we dispatch a call to iput to run later, to prevent a
deadlock from occurring.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes#11527Closes#11530
If there is no scsi_debug module, then this test
must be skipped, in this case cleanup routine should
be prepared for absent pool.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#11534
Need to destroy the pthread mutex created in uu_avl_pool_create.
https://svnweb.freebsd.org/base?view=revision&revision=262912
Obtained from: FreeBSD
Sponsored by: Spectra Logic Corporation
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11528
The runtime of vdev_validate is dominated by the disk accesses in
vdev_label_read_config. Speed it up by validating all vdevs in
parallel using a taskq.
Sponsored by: Axcient
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11470
This is similar to what we already do in vdev_geom_read_config.
Sponsored by: Axcient
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11470
metaslab_init is the slowest part of importing a mature pool, and it
must be repeated hundreds of times for each top-level vdev. But its
speed is dominated by a few serialized disk accesses. That can lead to
import times of > 1 hour for pools with many top-level vdevs on spinny
disks.
Speed up the import by using a taskqueue to parallelize vdev_load across
all top-level vdevs.
This also requires adding mutex protection to
metaslab_class_t.mc_historgram. The mc_histogram fields were
unprotected when that code was first written in "Illumos 4976-4984 -
metaslab improvements" (OpenZFS
f3a7f6610f). The lock wasn't added until
3dfb57a35e, though it's unclear exactly
which fields it's supposed to protect. In any case, it wasn't until
vdev_load was parallelized that any code attempted concurrent access to
those fields.
Sponsored by: Axcient
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11470
zfs-program.8 has an orphan link, fix it.
https://svnweb.freebsd.org/base?view=revision&revision=360080
Obtained from: FreeBSD
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11529
In order for cppcheck to perform a proper analysis it needs to be
aware of how the sources are compiled (source files, include
paths/files, extra defines, etc). All the needed information is
available from the Makefiles and can be leveraged with a generic
cppcheck Makefile target. So let's add one.
Additional minor changes:
* Removing the cppcheck-suppressions.txt file. With cppcheck 2.3
and these changes it appears to no longer be needed. Some inline
suppressions were also removed since they appear not to be
needed. We can add them back if it turns out they're needed
for older versions of cppcheck.
* Added the ax_count_cpus m4 macro to detect at configure time how
many processors are available in order to run multiple cppcheck
jobs. This value is also now used as a replacement for nproc
when executing the kernel interface checks.
* "PHONY =" line moved in to the Rules.am file which is included
at the top of all Makefile.am's. This is just convenient becase
it allows us to use the += syntax to add phony targets.
* One upside of this integration worth mentioning is it now allows
`make cppcheck` to be run in any directory to check that subtree.
* For the moment, cppcheck is not run against the FreeBSD specific
kernel sources. The cppcheck-FreeBSD target will need to be
implemented and testing on FreeBSD to support this.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11508
Identical condition and return expression 'rc', return value is
always 0.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11508
The ASSERT that the passed pointer isn't NULL appears after the
pointer has already been dereferenced. Remove the redundant check.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11508
The double free reported for the realloc() failure branch is a
false positive. It should be resolved in cppcheck 2.4 but for
the benefit of older versions we supress the warning.
https://trac.cppcheck.net/ticket/9292
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11508
Explicitly check for NULL to satisfy cppcheck that "val" can never
be NULL when passed to printf(). This looks like a false positive
since is_blank_str() can never take the false conditional branch
when passed a NULL. But there's no harm in adding the extra check.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11508
When scrubbing, (non-sequential) resilvering, or correcting a checksum
error using RAIDZ parity, ZFS should heal any incorrect RAIDZ parity by
overwriting it. For example, if P disks are silently corrupted (P being
the number of failures tolerated; e.g. RAIDZ2 has P=2), `zpool scrub`
should detect and heal all the bad state on these disks, including
parity. This way if there is a subsequent failure we are fully
protected.
With RAIDZ2 or RAIDZ3, a block can have silent damage to a parity
sector, and also damage (silent or known) to a data sector. In this
case the parity should be healed but it is not.
The problem can be noticed by scrubbing the pool twice. Assuming there
was no damage concurrent with the scrubs, the first scrub should fix all
silent damage, and the second scrub should be "clean" (`zpool status`
should not report checksum errors on any disks). If the bug is
encountered, then the second scrub will repair the silently-damaged
parity that the first scrub failed to repair, and these checksum errors
will be reported after the second scrub. Since the first scrub repaired
all the damaged data, the bug can not be encountered during the second
scrub, so subsequent scrubs (more than two) are not necessary.
The root cause of the problem is some code that was inadvertently added
to `raidz_parity_verify()` by the DRAID changes. The incorrect code
causes the parity healing to be aborted if there is damaged data
(`rc_error != 0`) or the data disk is not present (`!rc_tried`). These
checks are not necessary, because we only call `raidz_parity_verify()`
if we have the correct data (which may have been reconstructed using
parity, and which was verified by the checksum).
This commit fixes the problem by removing the incorrect checks in
`raidz_parity_verify()`.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#11489Closes#11510
- refactor cleanup routines into common kshlib zpool_export_cleanup func
- don't require physical disks to test, just use files
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Will Andrews <will@firepipe.net>
Closes#11518
zfs-load-key.sh is called by the dracut-pre-mount.service unit which has
no explicit 'After' dependency on zfs-import.target. That way it can be
that the pool has not yet been imported and the zfs-load-key.sh finishes
without ever seeing the relevant pool.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Lorenz Hüdepohl <dev@stellardeath.org>
Closes#11500
Create a common exit point for spa_export_common (a very long
function), which avoids missing steps on failure. This work
is helpful for the planned forced pool export changes.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Will Andrews <will@firepipe.net>
Closes#11514
Instead of just failing, indicate the expected and actual value and
source as a NOTE. Tests using this failed in an earlier version of
the changeset and this information helped find the cause.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Will Andrews <will@firepipe.net>
Closes#11517
There is an identical definition in zfs_set_common.kshlib already.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Will Andrews <will@firepipe.net>
Closes#11516
This avoids globbing together multiple lines in the log, if you happen
to specify LOGAPI_DEBUG because you want to see it.
Signed-off-by: Will Andrews <will@firepipe.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11515
Like any other thread created by thread_create() we need to call
thread_exit() to properly clean it up. In particular, this ensures the
tsd hash for the thread is cleared.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#11512
By default, FreeBSD does not allow zpools to be backed by zvols (that
can be changed with the "vfs.zfs.vol.recursive" sysctl). When that
sysctl is set to 0, the kernel does not attempt to read zvols when
looking for vdevs. But the zpool command still does. This change brings
the zpool command into line with the kernel's behavior. It speeds "zpool
import" when an already imported pool has many zvols, or a zvol with
many snapshots.
https://svnweb.freebsd.org/base?view=revision&revision=357235https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=241083https://reviews.freebsd.org/D22077
Obtained from: FreeBSD
Reported by: Martin Birgmeier <d8zNeCFG@aon.at>
Sponsored by: Axcient
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11502
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11503
It was observed that vdev_id exists silently when
the $CONFIG file is missing.
This patch adds error message in case vdev_id is
called without default $CONFIG or '-c'. This makes
end user observe the exit message more easily.
Before Patch:
~~~~~~~~~~~~~
$ ./cmd/vdev_id/vdev_id
$
After Patch:
~~~~~~~~~~~~
$ ./cmd/vdev_id/vdev_id
Error: Config file "/etc/zfs/vdev_id.conf" not found
$
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Closes#11498
Fix two minor errors reported by cppcheck:
In module/zfs/abd.c (abd_get_offset_impl), add non-NULL
assertion to prevent NULL dereference warning.
In module/zfs/arc.c (l2arc_write_buffers), change 'try'
variable to 'pass' to avoid C++ reserved word.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Colm Buckley <colm@tuatha.org>
Closes#11507
Follow up for commit 624222a, value asserted <= SPA_OLD_MAXBLOCKSIZE
instead of SPA_MAXBLOCKSIZE as it should be after the previous change.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes#11501
Provide a basic test coverage for io_uring I/O.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#11497
Set VIRF_MOUNTPOINT flag on snapshot mountpoint.
Authored-by: Mateusz Guzik <mjg@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#11458
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#11458
When creating a pool only features supported by both user and
kernel space should be enabled. Furthermore, improve the error
messages when attempting to create, or add, a dRAID vdev when
the dRAID feature is not supported by the kernel modules.
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11492
Mixing ZIL and normal allocations has several problems:
1. The ZIL allocations are allocated, written to disk, and then a few
seconds later freed. This leaves behind holes (free segments) where the
ZIL blocks used to be, which increases fragmentation, which negatively
impacts performance.
2. When under moderate load, ZIL allocations are of 128KB. If the pool
is fairly fragmented, there may not be many free chunks of that size.
This causes ZFS to load more metaslabs to locate free segments of 128KB
or more. The loading happens synchronously (from zil_commit()), and can
take around a second even if the metaslab's spacemap is cached in the
ARC. All concurrent synchronous operations on this filesystem must wait
while the metaslab is loading. This can cause a significant performance
impact.
3. If the pool is very fragmented, there may be zero free chunks of
128KB or more. In this case, the ZIL falls back to txg_wait_synced(),
which has an enormous performance impact.
These problems can be eliminated by using a dedicated log device
("slog"), even one with the same performance characteristics as the
normal devices.
This change sets aside one metaslab from each top-level vdev that is
preferentially used for ZIL allocations (vdev_log_mg,
spa_embedded_log_class). From an allocation perspective, this is
similar to having a dedicated log device, and it eliminates the
above-mentioned performance problems.
Log (ZIL) blocks can be allocated from the following locations. Each
one is tried in order until the allocation succeeds:
1. dedicated log vdevs, aka "slog" (spa_log_class)
2. embedded slog metaslabs (spa_embedded_log_class)
3. other metaslabs in normal vdevs (spa_normal_class)
The space required for the embedded slog metaslabs is usually between
0.5% and 1.0% of the pool, and comes out of the existing 3.2% of "slop"
space that is not available for user data.
On an all-ssd system with 4TB storage, 87% fragmentation, 60% capacity,
and recordsize=8k, testing shows a ~50% performance increase on random
8k sync writes. On even more fragmented systems (which hit problem #3
above and call txg_wait_synced()), the performance improvement can be
arbitrarily large (>100x).
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Don Brady <don.brady@delphix.com>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#11389
On openSUSE the initrd has systemctl in /usr/bin, check this path as
well.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Lorenz Hüdepohl <dev@stellardeath.org>
Closes#11487
zgenhostid(8) is used to modify or create /etc/hostid. This
administrative tool is currently installed to bindir. System utilities
are typically placed in sbin.
Modify the installation directory for zgenhostid. Additionally, track
this change in its use in dracut and the rpm installation.
Authored-by: наб <nabijaczleweli@nabijaczleweli.xyz>
Authored-by: Antonio Russo <aerusso@aerusso.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Antonio Russo <aerusso@aerusso.net>
Closes#11485
The ZFS_IOC_POOL_TRYIMPORT ioctl returns an nvlist from the kernel to a
preallocated buffer in userland. Userland must guess how large the
buffer should be. If it undersizes it, it must reallocate and try
again. That can cost a lot of time for large pools.
OpenZFS commit 28b40c8a6e set the guess at "zc.zc_nvlist_conf_size * 4"
without explanation. On my system, that is too small. From experiment,
x 32 is a better multiplier. But I don't know how to calculate it
theoretically.
Sponsored by: Axcient
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alek Pinchuk <apinchuk@axcient.com>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11469
zpool_read_label doesn't need the full labels including uberblocks. It
only needs the vdev_phys_t. This reduces by half the amount of data
read to check for a label, speeding up "zpool import", "zpool
labelclear", etc.
Originally committed as
https://cgit.freebsd.org/src/commit/?id=63f8025d6acab1b334373ddd33f940a69b3b54cc
Obtained from: FreeBSD
Sponsored by: Spectra Logic Corp, Axcient
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alek Pinchuk <apinchuk@axcient.com>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#11467
As part of commit 1c2358c1 the custom uio_prefaultpages() code
was removed in favor of using the generic kernel provided
iov_iter_fault_in_readable() interface. Unfortunately, it
turns out that up until the Linux 4.7 kernel the function would
only ever fault in the first iovec of the iov_iter. The result
being uiomove_iov() may hang waiting for the page.
This commit effectively restores the custom uio_prefaultpages()
pages code for Linux 4.9 and earlier kernels which contain the
troublesome version of iov_iter_fault_in_readable().
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11463Closes#11484
In FreeBSD the struct uio was just a typedef to uio_t. In order to
extend this struct, outside of the definition for the struct uio, the
struct uio has been embedded inside of a uio_t struct.
Also renamed all the uio_* interfaces to be zfs_uio_* to make it clear
this is a ZFS interface.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#11438
The `abd_get_offset_*()` routines create an abd_t that references
another abd_t, and doesn't allocate any pages/buffers of its own. In
some workloads, these routines may be called frequently, to create many
abd_t's representing small pieces of a single large abd_t. In
particular, the upcoming RAIDZ Expansion project makes heavy use of
these routines.
This commit adds the ability for the caller to allocate and provide the
abd_t struct to a variant of `abd_get_offset_*()`. This eliminates the
cost of allocating the abd_t and performing the accounting associated
with it (`abdstat_struct_size`). The RAIDZ/DRAID code uses this for
the `rc_abd`, which references the zio's abd. The upcoming RAIDZ
Expansion project will leverage this infrastructure to increase
performance of reads post-expansion by around 50%.
Additionally, some of the interfaces around creating and destroying
abd_t's are cleaned up. Most significantly, the distinction between
`abd_put()` and `abd_free()` is eliminated; all types of abd_t's are
now disposed of with `abd_free()`.
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Issue #8853Closes#11439
