arc_summary3 reports L2ARC writes in bytes. However, the related
arc_stat is reported as hits. arc_summary2 report this correctly.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes#10717
`thread_create` on FreeBSD stringifies the argument passed as the
thread function to create a name for the thread. The thread name for
`l2arc_dev_rebuild_start` ended up with `(void (*)(void *))` in it.
Change the type signature so the function does not need to be cast
when creating the thread. Rename the function to
`l2arc_dev_rebuild_thread` for clarity and consistency, as well.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Amanakis <gamanakis@gmail.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10716
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
When reading compressed blocks from the L2ARC, with
compressed ARC disabled, arc_hdr_size() returns
LSIZE rather than PSIZE, but the actual read is PSIZE.
This causes l2arc_read_done() to compare the checksum
against the wrong size, resulting in checksum failure.
This manifests as an increase in the kstat l2_cksum_bad
and the read being retried from the main pool, making the
L2ARC ineffective.
Add new L2ARC tests with Compressed ARC enabled/disabled
Blocks are handled differently depending on the state of the
zfs_compressed_arc_enabled tunable.
If a block is compressed on-disk, and compressed_arc is enabled:
- the block is read from disk
- It is NOT decompressed
- It is added to the ARC in its compressed form
- l2arc_write_buffers() may write it to the L2ARC (as is)
- l2arc_read_done() compares the checksum to the BP (compressed)
However, if compressed_arc is disabled:
- the block is read from disk
- It is decompressed
- It is added to the ARC (uncompressed)
- l2arc_write_buffers() will use l2arc_apply_transforms() to
recompress the block, before writing it to the L2ARC
- l2arc_read_done() compares the checksum to the BP (compressed)
- l2arc_read_done() will use l2arc_untransform() to uncompress it
This test writes out a test file to a pool consisting of one disk
and one cache device, then randomly reads from it. Since the arc_max
in the tests is low, this will feed the L2ARC, and result in reads
from the L2ARC.
We compare the value of the kstat l2_cksum_bad before and after
to determine if any blocks failed to survive the trip through the
L2ARC.
Sponsored-by: The FreeBSD Foundation
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allanjude@freebsd.org>
Closes#10693
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
Use github workflow to run checkstyle
- use free (for OS projects) resources
- starts for every commit and branch
- work on forks, contributors may use it
before creating PRs
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#10705
- It doesn't work now.
- It has to be manually edited on tests changes.
(even on test runtime changes!)
- Travis gives too small time to run to be useful.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#10704
Metaslabs are now (usually) loaded and unloaded infrequently, but when
that is not the case, it is useful to have a log of when and why these
events happened.
This commit enables the zfs_dbgmsg() in metaslab_load(), and adds a
zfs_dbgmsg() in metaslab_unload().
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10683
The arc_adapt() function tunes LRU/MLU balance according to 4 types of
cache hits (which is passed as state agrument): ghost LRU, LRU, MRU,
ghost MRU. If this function is called with wrong cache hit (state),
adaptation will be sub-optimal and performance will suffer.
Some time ago upstream received this commit:
6950 ARC should cache compressed data) in arc_read() do next
sequence (access to ghost buffer)
Before this commit, hit to any ghost list was passed arc_adapt() before
call to arc_access() which revive element in cache and change state from
ghost to real hit.
After this commit, the order of calls was reverted and arc_adapt() is
now called only with «real» hits even if hit was in one of two ghost
lists, which renders ghost lists useless and breaks the ARC algorithm.
FreeBSD fixed this problem locally in Change D19094 / Commit r348772.
This change is an adaptation of the above commit to the current arc
code.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10548Closes#10618
The 'zfs share -a' currently skips any filesystems which
have 'canmount=noauto' set. This behavior is unexpected since the
one would expect 'zfs share -a' to share any mounted filesystem
that has the 'sharenfs' property already set.
This changes the behavior of 'zfs share -a' to allow the sharing
of 'canmount=noauto' datasets if they are mounted.
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Don Brady <don.brady@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Signed-off-by: George Wilson <gwilson@delphix.com>
External-issue: DLPX-71313
Closes#10688
The KMOD name is "zfs" instead of "openzfs" when building in FreeBSD.
Define a ZFS_KMOD symbol as "zfs" when IN_BASE is defined, otherwise
"openzfs".
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10699
The make_request_fn and associated API was replaced recently in a
Linux 5.9 merge, to replace its functionality with a new submit_bio
member in struct block_device_operations.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#10696
This change appears to primarily be a name change for the enum. Had
to update the test logic so that it works so long as either one of
these is present (favoring the newer one). Additionally, as this is
newer, it only shows up in node_page_item, so this commit doesn't
test zone_page_item for the same enum.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#10696
Many of the block device operations (often functions with bdev in
the name) were moved into linux/blkdev.h from linux/fs.h. Seems
that this header is already included where needed in the code, but
in the autoconf tests it was missing causing false negatives. This
commit has those tests include linux/fs.h (old location) and now
also linux/blkdev.h (new locations).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes#10696
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allanjude@freebsd.org>
Closes#10694
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
In various other pieces of logic have resulted in situations where
we double-free space in ZFS. This in turn results in a double-add
to the range trees. These issues have been much more difficult to
diagnose than they should have been, because the error handling
around this case is much weaker than around the double remove case.
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes#10654
Bring zfs-tests.sh in to compliance with the other scripts
by converting it /bin/sh for to avoid a dependency on bash.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10640
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
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
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
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
Pool-wide metadata is stored in the MOS (Meta Object Set). This
metadata is stored in triplicate, in addition to any pool-level
reduncancy (e.g. RAIDZ). However, if all 3+ copies of this metadata are
not available, we can still get EIO/ECKSUM when reading from the MOS.
If we encounter such an error in syncing context, we have typically
already committed to making a change that we now can't do because of the
corrupt/missing metadata. We typically "handle" this with a `VERIFY()`
or `zfs_panic_recover()`. This prevents the system from continuing on
in an undefined state, while minimizing the amount of error-handling
code.
However, there are some code paths that ignore these i/o errors, or
`ASSERT()` that they don't happen. Since assertions are disabled on
non-debug builds, they effectively ignore them as well. This can lead
to ZFS continuing on in an incorrect state, potentially leading to
on-disk inconsistencies.
This commit adds handling for these i/o errors on MOS metadata,
typically with a `VERIFY()`:
* Handle error return from `zap_cursor_retrieve()` in 4 places in
`dsl_deadlist.c`.
* Handle error return from `zap_contains()` in `dsl_dir_hold_obj()`.
Turns out this call isn't necessary because we can always call
`zap_lookup()`.
* Handle error return from `zap_lookup()` in `dsl_fs_ss_limit_check()`.
* Handle error return from `zap_remove()` in `dsl_dir_rename_sync()`.
* Handle error return from `zap_lookup()` in
`dsl_dir_remove_livelist()`.
* Handle error return from `dsl_process_sub_livelist()` in
`spa_livelist_delete_cb()`.
Additionally:
* Augment the internal history log message for `zfs destroy` to note
which method is used (e.g. bptree, livelist, or, synchronous) and the
mintxg.
* Correct a comment in `dbuf_init()`.
* Correct indentation in `dsl_dir_remove_livelist()`.
Reviewed by: Sara Hartse <sara.hartse@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10643
3442c2a02d added new `arc_wait_for_eviction` tracepoint, which fails to
compile, when tracepoints are enabled.
The tracepoint definition begins with `DEFINE_ARC_WAIT_FOR_EVICTION_EVENT`
and is a multi-line definition, so this fixes the backslash
and parenthesis accordingly.
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Closes#10669
This is a minor change to the systemd service templates that verifies
the zfs kernel module is loaded by the kernel prior to attempting to
import any zpool.
The services check for the presence of /sys/module/zfs which indicates
the zfs is module is loaded. This uses the systemd built-in check
ConditionPathIsDirectory.
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Thode <prometheanfire@gentoo.org>
Signed-off-by: Jonathon Fernyhough <jonathon.fernyhough@york.ac.uk>
Closes#10663
In case the L2ARC rebuild was canceled, do not log to spa history
log as the pool may be in the process of being removed and a panic
may occur:
BUG: kernel NULL pointer dereference, address: 0000000000000018
RIP: 0010:spa_history_log_internal+0xb1/0x120 [zfs]
Call Trace:
l2arc_rebuild+0x464/0x7c0 [zfs]
l2arc_dev_rebuild_start+0x2d/0x130 [zfs]
? l2arc_rebuild+0x7c0/0x7c0 [zfs]
thread_generic_wrapper+0x78/0xb0 [spl]
kthread+0xfb/0x130
? IS_ERR+0x10/0x10 [spl]
? kthread_park+0x90/0x90
ret_from_fork+0x35/0x40
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes#10659
zfs_jail was not using zfs_ioctl so failed to map the IOC number
correctly. Use zfs_ioctl to perform the jail ioctl and add a test
case for FreeBSD.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10658
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
ZFS recv should return a useful error message when an invalid index
property value is provided in the send stream properties nvlist
With a compression= property outside of the understood range:
Before:
```
receiving full stream of zof/zstd_send@send2 into testpool/recv@send2
internal error: Invalid argument
Aborted (core dumped)
```
Note: the recv completes successfully, the abort() is likely just to
make it easier to track the unexpected error code.
After:
```
receiving full stream of zof/zstd_send@send2 into testpool/recv@send2
cannot receive compression property on testpool/recv: invalid property
value received 28.9M stream in 1 seconds (28.9M/sec)
```
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#10631
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
FreeBSD recently integrated a change which causes \s in a regex to
throw an error instead of silently being misinterpreted as an s.
Change the regex in zpool_colors.ksh to use [[:space:]].
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes#10651
FreeBSD uses more stack space in debug configurations and can overflow
the stack while formatting the error message when the call depth limit
of 20 frames is reached. This is readily reproduced by running the
gsub recursion test with increased kstack size. I hit the panic with
16 pages per kstack, and noticed it go away when bumped to 17.
Reserve an additional 64 bytes on the stack when building for FreeBSD.
This is enough to avoid the panic with a deep stack while not wasting
too much space when the default stack size is used.
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10634
Rather than just saying there was an internal error, provide any
context we might have to the user to help them understand the issue.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#10632
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#10636
This was causing all later errno's to have the incorrect value.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#10649
When a clone is promoted, its livelist is no longer accurate, so it is
discarded. If the clone's origin is also a clone (i.e. we are promoting
a clone of a clone), then the origin's livelist is also no longer
accurate, so it should be discarded, but the code doesn't actually do
that.
Consider a pool with:
* Filesystem A
* Clone B, a clone of A
* Clone C, a clone of B
If we promote C, it discards C's livelist. It should discard B's
livelist, but that is not happening. The impact is that when B is
destroyed, we use the livelist to find the blocks to free, but the
livelist is no longer correct so we end up freeing blocks that are still
in use by C. The incorrectly-freed blocks can be reallocated causing
checksum errors. And when C is destroyed it can double-free the
incorrectly-freed blocks.
The problem is that we remove the livelist of `origin_ds->ds_dir`, but
the origin snapshot has already been moved to the promoted dsl_dir. So
this is actually trying to remove the livelist of the promoted dsl_dir,
which was already removed. As explained in a comment in the beginning
of `dsl_dataset_promote_sync()`, we need to use the saved `odd` for the
origin's dsl_dir.
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10652
* Fixed a typo that cause one of the variations to be a no-op
* Added additional coverage for adding special vdev after pool create
* Added additional coverage for using 4K sector size
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Don Brady <don.brady@delphix.com>
Closes#10641
In `vdev_load()`, we look up several entries in the `vdev_top_zap`
object. In most cases, if we encounter an i/o error, it will be
returned to the caller. However, when handling
`VDEV_TOP_ZAP_ALLOCATION_BIAS`, if we get an i/o error, we may continue
on, which in theory could cause us to not realize that a vdev should be
used only for `special` allocations.
In practice, if we encountered an i/o error while looking for
`VDEV_TOP_ZAP_ALLOCATION_BIAS` in the `vdev_top_zap`, we'd also get an
i/o error while looking for other entries in the same object, and thus
the zpool open/import would fail. Therefore the impact of this problem
is negligible.
This commit adds error handling for i/o errors while accessing the
`vdev_top_zap`, so that we aren't relying on unrelated code to fail for
us.
Reviewed-by: Don Brady <don.brady@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10637
