[2.2.1] zvol improvements #15500

ixhamza · 2023-11-07T15:22:45Z

Motivation and Context

This PR consists of the following three separate commits:

Implement internal zvol threading as a property.
Fix delayed update to zvol block device ro entry.
Cleanup around zvol volmode and snapdev set property.

Description

Detailed descriptions are added in individual commits.

How Has This Been Tested?

Readonly Property:

Before the patch:

# Changing readonly property does not take effect until first IO
zfs set readonly=on tank/zv1
cat /sys/block/zd0/ro 
0
dd if=/dev/zero of=/dev/zvol/tank/zv1 bs=512 count=1
cat /sys/block/zd0/ro 
1

After the patch:

# Changing readonly property immediately takes effect
zfs set readonly=on tank/zv1
cat /sys/block/zd0/ro 
1

zvol threading:

Switched zvol threading for specific zvols and checked through flamegraph:

zfs set volthreading=off tank/zv1
zfs get volthreading tank/zv1
NAME      PROPERTY      VALUE           SOURCE
tank/zv1  volthreading  off             local

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.

zvol_set_volmode() and zvol_set_snapdev() share a common code path. Merge this shared code path into zvol_set_common(). Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Alexander Motin <mav@FreeBSD.org> Signed-off-by: Ameer Hamza <ahamza@ixsystems.com> Closes openzfs#15409

Currently, zvol threading can be switched through the zvol_request_sync module parameter system-wide. By making it a zvol property, zvol threading can be switched per zvol. Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Alexander Motin <mav@FreeBSD.org> Signed-off-by: Ameer Hamza <ahamza@ixsystems.com> Closes openzfs#15409

The change in the zvol readonly property does not update the block device readonly entry until the first IO to the ZVOL. This patch addresses the issue by updating the block device readonly property from the set property IOCTL call. Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Alexander Motin <mav@FreeBSD.org> Signed-off-by: Ameer Hamza <ahamza@ixsystems.com> Closes openzfs#15409

tonyhutter

Thank you for this backport!

tonyhutter · 2023-11-08T20:31:53Z

I pulled these into #15498

ixhamza added 3 commits November 7, 2023 19:19

amotin requested a review from tonyhutter November 7, 2023 15:26

ixhamza mentioned this pull request Nov 7, 2023

zfs-2.2.1 patch stack #15498

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tonyhutter approved these changes Nov 8, 2023

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tonyhutter closed this Nov 8, 2023

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[2.2.1] zvol improvements #15500

[2.2.1] zvol improvements #15500

ixhamza commented Nov 7, 2023

tonyhutter left a comment

tonyhutter commented Nov 8, 2023

[2.2.1] zvol improvements #15500

[2.2.1] zvol improvements #15500

Conversation

ixhamza commented Nov 7, 2023

Motivation and Context

Description

How Has This Been Tested?

Readonly Property:

zvol threading:

Types of changes

Checklist:

tonyhutter left a comment

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tonyhutter commented Nov 8, 2023