openzfs/zfs

zfs holds -r does not work on non-snapshot datasets

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#9,822 opened on Jan 8, 2020

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Type: Defectgood first issue

Description

System information

Type Version/Name
Distribution Name Arch Linux
Distribution Version rolling
Linux Kernel 5.4.6
Architecture x86_64
ZFS Version 0.8.2-1
SPL Version 0.8.2-1

Describe the problem you're observing

If trying to list all of the holds on all of the snapshots on a dataset, I would expect zfs holds -r [dataset] to list, per snapshot, all of the holds. On FreeBSD 12.1 this works as expected. However, on ZFS on Linux it just says "not a snapshot" and lists nothing.

Describe how to reproduce the problem

  • Create a snapshot on a dataset
  • Create a hold on that snapshot
  • Run zfs holds -r [dataset]@[snapshot] and observe the hold
  • Run zfs holds -r [dataset] and observe the error

Include any warning/errors/backtraces from the system logs

N/A

Contributor guide

Tech stack
c
Domain
backend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C programmingZFS command line toolsLinux/Unix system knowledge
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Investigate the implementation of the 'zfs holds r' command in the ZFS source code, specifically in the 'cmd/zfs/zfs main.c' file. The issue mentions that the recursive flag does not work on non snapshot datasets, while it works on FreeBSD. Look for how the ' r' flag is processed and how the dataset argument is handled. Compare the Linux and FreeBSD implementations if available. Check the man page for expected behavior and verify if there is any existing comment or code comment regarding this discrepancy. The issue has no linked PRs, so the fix would involve modifying the argument parsing or iteration logic to include snapshots when the ' r' flag is used.