md: Fix getting bitmap location on latest kernels

[vojtechtrefny]

The 'md/bitmap/location' file no longer exists in sysfs when the bitmap is not set. The location of the "internal" bitmap is also slightly differet now.

[gemini-code-assist]

Summary of Changes

Hello @vojtechtrefny, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses compatibility issues with recent Linux kernel versions regarding MD RAID bitmap location reporting. It ensures that the system correctly identifies when a bitmap is not set by checking for the existence of the relevant sysfs file and updates the expected internal bitmap locations in tests to reflect current kernel behavior. This prevents potential errors and provides accurate information about MD RAID configurations.

Highlights

• Kernel Compatibility: Updated the logic for retrieving MD RAID bitmap locations to be compatible with recent Linux kernel changes, where the 'md/bitmap/location' sysfs file may no longer exist if the bitmap is not set.
• Bitmap Location Handling: Implemented a check to return 'none' if the sysfs bitmap location file does not exist, preventing errors when the bitmap is not present.
• Test Updates: Modified unit tests to account for a new possible 'internal' bitmap location ('+2'), alongside the existing ('+8'), reflecting updated kernel behavior.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Summary of Changes

Hello @vojtechtrefny, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses compatibility issues with recent Linux kernel updates affecting how MD (RAID) bitmap locations are reported via sysfs. It ensures the system correctly identifies when a bitmap location is not set and updates test cases to accommodate new possible values for internal bitmap locations, preventing errors and ensuring accurate reporting.

Highlights

• Sysfs Path Handling: The mdraid plugin now gracefully handles the scenario where the /sys/class/block/%s/md/bitmap/location file no longer exists in sysfs when a bitmap is not set, returning 'none' instead of an error.
• Internal Bitmap Location: The tests for md_get_bitmap_location have been updated to account for a new possible value ('+2') for the internal bitmap location, alongside the previously expected value ('+8'), reflecting recent kernel changes.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request addresses an issue with detecting MD RAID bitmap location on newer kernels. The change in src/plugins/mdraid.c correctly handles cases where the bitmap sysfs file is absent. However, this introduces a memory leak, for which I've provided a fix. The test adjustments in tests/mdraid_test.py are appropriate to accommodate the varied bitmap locations on different kernels.

[gemini-code-assist]

Code Review

This pull request addresses an issue with retrieving MD RAID bitmap locations on newer kernels by handling cases where the sysfs file may not exist and by updating tests for new bitmap location values. The logic in src/plugins/mdraid.c is mostly correct, but it introduces a memory leak in an early return path. I've provided a specific comment and a code suggestion to fix this leak. The changes in tests/mdraid_test.py are appropriate and correctly adapt the tests to the new kernel behavior.

[tbzatek]

That's the way I like it, thanks!