NAS-133615 / None / Revert "Linux: Enable Direct IO by default"

[ixhamza]

Motivation and Context

Reverting Direct IO enablement after encountering kernel panic during NVIDIA driver installation through systemd-sysext (similar to OpenZFS Issue #16956). Additionally, multiple upstream bugs have been reported related to Direct IO after its enablement.

• Block Cloning fallback with O_DIRECT flag causes kernel panic in older kernel versions
• Direct IO resulting in Veeam failing "to open storage for read/write access" with direct=standard
• Creating a loop device over ZFS file system causes NULL pointer exception when direct=always is set
• copy_file_range() returns EAGAIN for direct=always but succeeds for direct=standard on non-recordsize-aligned requests

Description

How Has This Been Tested?

• CI Testing
• Scale Build
• API Tests seems to be failing unrealted to this changeset. Same python exception in recent master/INCREMENTAL as well, @yocalebo:

+ sudo ixnode create --iso /data/ISO/api_tests/2634/install.iso --nickname=api_tests__2634 --ha
[Pipeline] sh
+ sudo ixnode boot ha001 --wait
Traceback (most recent call last):
  File "/usr/local/bin/ixnode", line 33, in <module>
    sys.exit(load_entry_point('ixnode==0.1.2', 'console_scripts', 'ixnode')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/dist-packages/ixnode-0.1.2-py3.11.egg/ixnode/ixnode.py", line 1598, in main
  File "/usr/local/lib/python3.11/dist-packages/ixnode-0.1.2-py3.11.egg/ixnode/ixnode.py", line 1025, in ixnode_boot
  File "/usr/local/lib/python3.11/dist-packages/ixnode-0.1.2-py3.11.egg/ixnode/expect.py", line 242, in wait_for_boot
  File "/usr/lib/python3/dist-packages/pexpect/spawnbase.py", line 343, in expect
    return self.expect_list(compiled_pattern_list,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/pexpect/spawnbase.py", line 372, in expect_list
    return exp.expect_loop(timeout)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/pexpect/expect.py", line 181, in expect_loop
    return self.timeout(e)
           ^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/pexpect/expect.py", line 144, in timeout
    raise exc
pexpect.exceptions.TIMEOUT: Timeout exceeded.
<pexpect.pty_spawn.spawn object at 0x7f90055bb710>
command: /usr/bin/virsh
args: ['/usr/bin/virsh', 'console', 'ha001_c1']
buffer (last 100 chars): b' 42, in _create_arguments\r\n    if item["type"] != "object":\r\n       ~~~~^^^^^^^^\r\nKeyError: \'type\'\r\n'
before (last 100 chars): b' 42, in _create_arguments\r\n    if item["type"] != "object":\r\n       ~~~~^^^^^^^^\r\nKeyError: \'type\'\r\n'
after: <class 'pexpect.exceptions.TIMEOUT'>

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.

[bugclerk]

Jira URL: https://ixsystems.atlassian.net/browse/NAS-133615

[bugclerk]

Not updating JIRA ticket https://ixsystems.atlassian.net/browse/NAS-133615 target versions as no JIRA version corresponds to this PR

[bugclerk]

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