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Fix activating large_microzap on receive - #18144

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behlendorf merged 1 commit into
openzfs:masterfrom
AustinWise:austin/large-microzap
Feb 5, 2026
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Fix activating large_microzap on receive#18144
behlendorf merged 1 commit into
openzfs:masterfrom
AustinWise:austin/large-microzap

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@AustinWise

@AustinWise AustinWise commented Jan 19, 2026 •
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Motivation and Context

Fixes #18143.

Description

When receiving a stream with the large microzap feature flag, the feature activation was not correctly recorded in two different ways:

  • The in-memory state of the feature activation is not captured.
  • dsl_dataset_activate_feature may be called when the feature is already recorded as active, causing a panic.

This PR fixes both problems.

How Has This Been Tested?

Two tests that fail on the master branch but pass with this PR.

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)
  • Quality assurance (non-breaking change which makes the code more robust against bugs)
  • 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:

@AustinWise

AustinWise commented Jan 19, 2026

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It looks like the call earlier in dmu_recv_begin_sync to dsl_dataset_activate_redaction could suffer from a similar issue: it does not check if the feature is already active before attempting to activate. I don't know enough about redacted datasets to write a test though.

@AustinWise
AustinWise force-pushed the austin/large-microzap branch from acc509d to c9ea6c9 Compare January 19, 2026 19:46
@AustinWise AustinWise changed the title Austin/large microzap Fix activating large_microzap on receive Jan 21, 2026
@AustinWise
AustinWise marked this pull request as ready for review January 21, 2026 16:18
@github-actions github-actions Bot added Status: Code Review Needed Ready for review and testing and removed Status: Work in Progress labels Jan 21, 2026
amotin
amotin reviewed Jan 23, 2026
View reviewed changes
Comment thread tests/runfiles/linux.run Resolved
@AustinWise
AustinWise marked this pull request as draft January 23, 2026 16:35
@github-actions github-actions Bot added Status: Work in Progress and removed Status: Code Review Needed Ready for review and testing labels Jan 23, 2026
@AustinWise
AustinWise force-pushed the austin/large-microzap branch 3 times, most recently from 72a537f to 8568dce Compare January 25, 2026 18:31
@AustinWise
Fix activating large_microzap on receive
c72ddf1 
This ensures that the in-memory state of the feature is recorded and
that `dsl_dataset_activate_feature` is not called when the feature
is already active.

Signed-off-by: Austin Wise <AustinWise@gmail.com>
@AustinWise
AustinWise force-pushed the austin/large-microzap branch from 8568dce to c72ddf1 Compare January 25, 2026 21:52
@AustinWise
AustinWise marked this pull request as ready for review January 26, 2026 05:21
@github-actions github-actions Bot added Status: Code Review Needed Ready for review and testing and removed Status: Work in Progress labels Jan 26, 2026
behlendorf
behlendorf approved these changes Feb 5, 2026
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@behlendorf behlendorf left a comment

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Looks good. Thanks for running this down and putting together new test cases for it!

@behlendorf
behlendorf merged commit 4f180e0 into openzfs:master Feb 5, 2026
37 of 46 checks passed
tonyhutter pushed a commit to tonyhutter/zfs that referenced this pull request Feb 17, 2026
@AustinWise @tonyhutter
Fix activating large_microzap on receive
612d401 
This ensures that the in-memory state of the feature is recorded and
that `dsl_dataset_activate_feature` is not called when the feature
is already active.

Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Austin Wise <AustinWise@gmail.com>
Closes openzfs#18143
Closes openzfs#18144
lundman pushed a commit to openzfsonosx/openzfs-fork that referenced this pull request Jul 30, 2026
@AustinWise @lundman
Fix activating large_microzap on receive
1fb5d62 
This ensures that the in-memory state of the feature is recorded and
that `dsl_dataset_activate_feature` is not called when the feature
is already active.

Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Austin Wise <AustinWise@gmail.com>
Closes openzfs#18143
Closes openzfs#18144
snajpa pushed a commit to vpsfreecz/zfs that referenced this pull request Aug 5, 2026
@AustinWise @snajpa
Fix activating large_microzap on receive v2
32815c1 
This ensures that the in-memory state of the feature is recorded and
that `dsl_dataset_activate_feature` is not called when the feature
is already active.

Porting notes: The dmu_recv.c implementation and both focused receive
  tests are unchanged from upstream.  OpenZFS 2.3.8 does not yet have
  the adjacent DIO_STRICT tunable entry, so ZAP_MICRO_MAX_SIZE is placed
  after XATTR_COMPAT in the available tunables.cfg sequence.

Patch development history:
- v1: Upstream recorded large_microzap activation in receive state and
  added incremental and transitive receive coverage.
- v2: Adapted only the tunables.cfg insertion context to the 2.3.8 list
  and documented the unchanged source and test implementation and
  validation.

Validation: git diff --check, targeted cstyle for dmu_recv.c, and ksh
  syntax checks for both focused receive tests passed.  Changed
  implementation and test lines were compared with upstream; only
  tunables.cfg placement differs.  No build or ZTS was run.

Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Austin Wise <AustinWise@gmail.com>
Closes openzfs#18143
Closes openzfs#18144
Upstream: 4f180e0
Ported-by: Pavel Snajdr <snajpa@snajpa.net>
pull Bot pushed a commit to A-Archives-and-Forks/openzfs that referenced this pull request Sep 26, 2026
@AustinWise @lundman
Fix activating large_microzap on receive
4ad6303 
This ensures that the in-memory state of the feature is recorded and
that `dsl_dataset_activate_feature` is not called when the feature
is already active.

Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Austin Wise <AustinWise@gmail.com>
Closes openzfs#18143
Closes openzfs#18144
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Recieving a stream with the large microzap feature flag is not properly recorded

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