btrfs: Add bd_btrfs_delete_subvolume_recursive function

[vojtechtrefny]

Add a new function for deleting btrfs subvolumes with an option for recursive deletion using the --recursive flag (requires btrfs-progs

= 6.12). The existing bd_btrfs_delete_subvolume now delegates to
the new function with recursive=FALSE.

A new BD_BTRFS_TECH_MODE_DELETE_RECURSIVE tech mode is added and checked in bd_btrfs_is_tech_avail for the SUBVOL tech.

Fixes: #1107

Summary by CodeRabbit

• New Features

  • Added recursive subvolume deletion support for btrfs. The new function allows deleting subvolume hierarchies in a single operation. Requires btrfs-progs version 6.12 or later.

• Tests

  • Added test coverage for recursive subvolume deletion, including version compatibility validation.

[coderabbitai]

📝 Walkthrough

Walkthrough

This pull request adds support for recursive deletion of btrfs subvolumes by introducing a new function bd_btrfs_delete_subvolume_recursive with version requirement checking for btrfs-progs 6.12 or higher, alongside corresponding API declarations, implementation, and test coverage.

Changes

Cohort / File(s)	Summary
API Declarations src/lib/plugin_apis/btrfs.api, src/plugins/btrfs.h, docs/libblockdev-sections.txt	Added new public function bd_btrfs_delete_subvolume_recursive declaration and new mode flag BD_BTRFS_TECH_MODE_DELETE_RECURSIVE = 1 << 4 to the BDBtrfsTechMode enum; exported symbol added to documentation.
Core Implementation src/plugins/btrfs.c	Implemented bd_btrfs_delete_subvolume_recursive with conditional version 6.12 dependency checking; refactored bd_btrfs_delete_subvolume to delegate to the new recursive function with recursive=FALSE; updated bd_btrfs_is_tech_avail to perform version checks based on mode flags.
Test Coverage tests/btrfs_test.py	Added new test class with comprehensive test for recursive subvolume deletion, including nested subvolume creation and version-conditional error handling for btrfs-progs below 6.12.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 71.43% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title accurately and concisely describes the main change: adding a new bd_btrfs_delete_subvolume_recursive function to the btrfs API.
Linked Issues check	✅ Passed	The pull request fully implements the requirements from issue #1107: adds bd_btrfs_delete_subvolume_recursive function for recursive subvolume deletion, preserves API stability by keeping the existing function, and enforces btrfs-progs version 6.12 requirement.
Out of Scope Changes check	✅ Passed	All changes are directly related to implementing recursive subvolume deletion: new function declaration/implementation, tech mode enum, version checking logic, and comprehensive test coverage. No unrelated modifications detected.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

tests/btrfs_test.py (1)

270-280: Consider making the 6.12 gate coverage deterministic.

This test covers only one branch per host version. A small fake_utils/NOSTORAGE test for BlockDev.btrfs_is_tech_avail(BlockDev.BtrfsTech.SUBVOL, BlockDev.BtrfsTechMode.DELETE_RECURSIVE) would catch regressions in the new tech-mode gate regardless of the CI runner’s installed btrfs-progs version.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@tests/btrfs_test.py` around lines 270 - 280, Add a deterministic unit test
that checks the tech-mode gate instead of relying on host btrfs-progs: create a
small test in tests/btrfs_test.py (or new test module) that uses the
fake_utils/NOSTORAGE environment to simulate storage absent and asserts
BlockDev.btrfs_is_tech_avail(BlockDev.BtrfsTech.SUBVOL,
BlockDev.BtrfsTechMode.DELETE_RECURSIVE) returns the expected boolean; if true,
call BlockDev.btrfs_delete_subvolume_recursive(TEST_MNT, "subvol1", True, None)
and assert success, otherwise assert it raises GLib.GError with the "Too low
version of btrfs" message—this ensures both branches of the version gate are
covered deterministically.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@src/lib/plugin_apis/btrfs.api`:
- Around line 323-324: Update the gtk-doc text for the `@recursive` parameter in
the btrfs subvolume deletion docs (the gtk-doc block that mentions "@recursive"
in the btrfs API docs and the matching comment block in the btrfs plugin
implementation) to reflect upstream caveats: state that recursive deletion
requires btrfs-progs >= 6.12, is not atomic, and when run unprivileged
inaccessible child subvolumes may be skipped rather than deleted; ensure both
the documentation in the API gtk-doc block (the comment referring to `@recursive`)
and the corresponding comment in the btrfs.c plugin are changed to the new
wording so they match.

---

Nitpick comments:
In `@tests/btrfs_test.py`:
- Around line 270-280: Add a deterministic unit test that checks the tech-mode
gate instead of relying on host btrfs-progs: create a small test in
tests/btrfs_test.py (or new test module) that uses the fake_utils/NOSTORAGE
environment to simulate storage absent and asserts
BlockDev.btrfs_is_tech_avail(BlockDev.BtrfsTech.SUBVOL,
BlockDev.BtrfsTechMode.DELETE_RECURSIVE) returns the expected boolean; if true,
call BlockDev.btrfs_delete_subvolume_recursive(TEST_MNT, "subvol1", True, None)
and assert success, otherwise assert it raises GLib.GError with the "Too low
version of btrfs" message—this ensures both branches of the version gate are
covered deterministically.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 8d5866ad-1884-4568-85dc-f513ccc7cec7

📥 Commits

Reviewing files that changed from the base of the PR and between 81c7a4b and 45deda1.

📒 Files selected for processing (5)

• docs/libblockdev-sections.txt
• src/lib/plugin_apis/btrfs.api
• src/plugins/btrfs.c
• src/plugins/btrfs.h
• tests/btrfs_test.py

[vojtechtrefny]

/packit build

[vojtechtrefny]

/packit build