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Fix divide-by-zero in mmp_delay_update() #7391

Merged
merged 1 commit into from
Apr 6, 2018
Merged

Fix divide-by-zero in mmp_delay_update() #7391

merged 1 commit into from
Apr 6, 2018

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ofaaland
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@ofaaland ofaaland commented Apr 5, 2018 •
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Description

Replace vdev_count_leaves() with MAX(1,vdev_count_leaves()) in denominator of expression.

Motivation and Context

vdev_count_leaves() may return 0, resulting in divide-by-zero. Caught by Coverity.
Introduced by

  • 533ea04 Update mmp_delay on sync or skipped, failed write

How Has This Been Tested?

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)
  • Documentation (a change to man pages or other documentation)

Checklist:

  • My code follows the ZFS on Linux code style requirements.
  • I have updated the documentation accordingly.
  • I have read the CONTRIBUTING document.
  • I have added tests to cover my changes.
  • All new and existing tests passed.
  • All commit messages are properly formatted and contain Signed-off-by.
  • Change has been approved by a ZFS on Linux member.

@ofaaland
Fix divide-by-zero in mmp_delay_update()
3f391d4 
vdev_count_leaves() in the denominator may return 0, caught by Coverity.
Introduced by

* 533ea04 Update mmp_delay on sync or skipped, failed write

Signed-off-by: Olaf Faaland <[email protected]>
@ofaaland ofaaland force-pushed the b_mmp_no_div_zero branch from 53cb9b3 to 3f391d4 Compare April 5, 2018 17:09
@ofaaland ofaaland requested review from behlendorf and dinatale2 April 5, 2018 17:13
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codecov bot commented Apr 5, 2018 •
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Codecov Report

Merging #7391 into master will decrease coverage by 0.05%.
The diff coverage is 100%.

Impacted file tree graph

@@            Coverage Diff             @@
##           master    #7391      +/-   ##
==========================================
- Coverage   76.39%   76.33%   -0.06%     
==========================================
  Files         329      329              
  Lines      104248   104248              
==========================================
- Hits        79638    79576      -62     
- Misses      24610    24672      +62
Flag Coverage Δ
#kernel 76.34% <100%> (+0.17%) ⬆️
#user 65.67% <100%> (+0.02%) ⬆️

Continue to review full report at Codecov.

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@behlendorf behlendorf merged commit 0ba106e into openzfs:master Apr 6, 2018
@adilger
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adilger commented May 26, 2018

It looks like this patch still needs to be landed onto 0.7, or is vdev_count_leaves(spa) == 0 caused by something only on master (e.g. device removal)?

@ofaaland
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@tonyhutter , can you consider this for 0.7.10?

@tonyhutter
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Yep, I'll include it

tonyhutter pushed a commit to tonyhutter/zfs that referenced this pull request Aug 15, 2018
@ofaaland @tonyhutter
Fix divide-by-zero in mmp_delay_update()
e60b495 
vdev_count_leaves() in the denominator may return 0, caught by Coverity.
Introduced by

* 533ea04 Update mmp_delay on sync or skipped, failed write

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Giuseppe Di Natale <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Signed-off-by: Olaf Faaland <[email protected]>
Closes openzfs#7391
tonyhutter pushed a commit to tonyhutter/zfs that referenced this pull request Aug 23, 2018
@ofaaland @tonyhutter
Fix divide-by-zero in mmp_delay_update()
ce32ed6 
vdev_count_leaves() in the denominator may return 0, caught by Coverity.
Introduced by

* 533ea04 Update mmp_delay on sync or skipped, failed write

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Giuseppe Di Natale <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Signed-off-by: Olaf Faaland <[email protected]>
Closes openzfs#7391
@ofaaland ofaaland deleted the b_mmp_no_div_zero branch September 5, 2018 15:53
tonyhutter pushed a commit to tonyhutter/zfs that referenced this pull request Sep 5, 2018
@ofaaland @tonyhutter
Fix divide-by-zero in mmp_delay_update()
6b5cc49 
vdev_count_leaves() in the denominator may return 0, caught by Coverity.
Introduced by

* 533ea04 Update mmp_delay on sync or skipped, failed write

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Giuseppe Di Natale <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Signed-off-by: Olaf Faaland <[email protected]>
Closes openzfs#7391
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Reviewers

@dinatale2 dinatale2 dinatale2 approved these changes

@gmelikov gmelikov gmelikov approved these changes

@behlendorf behlendorf behlendorf approved these changes

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6 participants
@ofaaland @adilger @tonyhutter @behlendorf @gmelikov @dinatale2