added support for fs_context operations -> parse_param

[EricKim27]

This commit implements the fs_context_operations->parse_param(replacement for parse_options used at fill_super for kernels below 6.18) and modifies other related functions to work with the newly implemented operation.

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Summary by cubic

Add fs_context-based mount option parsing for kernels 6.18+, adding parse_param for journal_dev and journal_path, with proper context cleanup and journal loading. Legacy parse_options remains for older kernels.

• New Features

  • Implemented simplefs_parse_param using fs_parameter_spec/fs_parse for journal_dev (u32) and journal_path (string).
  • Added per-mount simplefs_fs_context; allocated in .init_fs_context, stored in fc->fs_private, and exposed via .parameters = &simplefs_param_specs.
  • In simplefs_fill_super (>=6.18), load the journal from journal_dev or resolve journal_path with kern_path and load if it’s a block device.

• Bug Fixes

  • Added .free in fs_context_operations to free journal_path and the context; free any existing journal_path before kstrdup() in parse_param.
  • Reordered path_put() to occur after d_inode() extraction (>=6.18) and after device checks in the legacy path to prevent a possible use-after-free.

^{Written for commit e60949b. Summary will update on new commits.}

[cubic-dev-ai]

2 issues found across 3 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="super.c">

<violation number="1" location="super.c:705">
P2: Missing path_put() after kern_path() leaks the looked-up path reference in the new journal_path fs_context path.</violation>
</file>

<file name="fs.c">

<violation number="1" location="fs.c:25">
P2: Allocated fs_context private data has no cleanup callback, so the mount context can leak when the fs_context is destroyed.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[jserv]

Thank @EricKim27 for contributing!