NAS-129309 / None / Add support for zvol block cloning

[ixhamza]

Motivation and Context

Add block cloning support for zvols, similar to existing file block cloning.

Description

This change introduces block cloning support for zvols. Given that the upstream kernel patch for block cloning is still pending merge, this feature is being implemented as a local patch for the Electric Eel Alpha freeze. However, we plan to upstream at least the generic zvol.c part.

Related Patches

• Kernel: NAS-129309 / None / Copy offload support for block devices linux#203
• SCST: NAS-129309 / None / Add XCOPY support in blkdev handler scst#37

How Has This Been Tested?

• Verified block cloning functionality across zvol devices and within the same zvol device.
• Validated cloned blocks through zdb.
• Conducted ZIL replay tests to ensure reliability.
• Tested on both single-queue (default for zfs) and multi-queue configurations.
• Observed significant performance improvements across all block sizes, with larger block sizes yielding better results.
• Achieved up to 30x performance improvement with a 32k block size (used by perf team) in a virtualized QEMU environment.
• Scale Build & API Tests.

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-129309

[bugclerk]

Not updating JIRA ticket https://ixsystems.atlassian.net/browse/NAS-129309 target versions as no JIRA version corresponds to this PR

[bugclerk]

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