vfs-test

CI and mailing list bridge for the Linux VFS subsystem. Runs as GitHub Actions on the linux-fsdevel/vfs mirror.

Overview

Three scheduled workflows keep the mirror in sync, turn mailing list patches into pull requests, and build+test every branch that changes:

kernel.org/vfs.git                      Patchwork (linux-fsdevel)
  vfs.all ──┐                                │
  vfs.base ─┤  sync.yml (daily)              │  bridge.yml (every 2h)
  vfs.fixes ┘      │                         │       │
                   ▼                         ▼       │
         GitHub linux-fsdevel/vfs                    │
           vfs.all.ci  ◄── CI files overlaid         │
           vfs.base.ci ◄── CI files overlaid         │
           vfs.fixes.ci◄── CI files overlaid         │
           pw/<id>/... ◄─────────────────────────────┘
                    │
                    ▼
              test.yml (on push)
                    │
           ┌────────┼────────┐
           ▼        ▼        ▼
        selftests  xfstests  ovl-fstests

Workflows

sync.yml -- Mirror kernel.org to GitHub

Runs once a day. Shallow-clones vfs.git from kernel.org, force-pushes the clean branches (vfs.all, vfs.base, vfs.fixes) to GitHub, then creates matching .ci branches with the CI files from this repository overlaid. Only pushes a .ci branch when its tree actually changes, so existing pw/ branches don't needlessly diverge.

bridge.yml -- Mailing list to pull request bridge (ml2pr)

Runs every two hours. Queries the Patchwork API for patch series delegated to the VFS maintainer, applies them with b4, and opens pull requests on GitHub targeting vfs.base.ci. This triggers CI automatically.

The bridge also:

• Rebases open pw/ PRs when vfs.base moves forward.
• Closes PRs when a newer version of the series supersedes them.
• Closes PRs when all patches have been merged upstream (patch-id comparison against vfs.base).
• Closes PRs that have gone stale (older than 14 days).

test.yml / kernel-build-test.yml -- Build and test matrix

Triggered on every push to any branch except the clean mirror branches and pw/**. A Python matrix generator (.github/scripts/matrix.py) produces the cross-product of build configurations and test suites:

Arch	Toolchain	Distributions	Test suites
x86_64	gcc	Fedora, Debian	selftests, xfstests, ovl-fstests

Each matrix entry:

1. Checks out the CI repo and clones mkosi-kernel.
2. Overlays the VFS kernel config fragment and mkosi configuration.
3. Builds the kernel and a bootable disk image with mkosi.
4. Boots the image in QEMU and runs the selected test suite via a dedicated systemd service unit.

Exit code 123 from the guest signals success (systemd SuccessActionExitStatus); anything else is a failure.

Test suites

VFS selftests

Runs the kernel's in-tree selftests for VFS-related subsystems:

• mount, mount_setattr, filelock, tmpfs
• pidfd, pid_namespace, cachestat

Known-flaky tests (filesystems:file_stressor, filelock:ofdlocks) are denylisted.

XFS fstests

Runs xfstests -g quick on XFS using dedicated test/scratch partitions provisioned by mkosi's repart configuration.

Overlayfs fstests

Same as XFS fstests but additionally runs the overlay/union test group with -overlay.

mkosi configuration

Located under ci/mkosi/:

• mkosi.conf.d/ -- mkosi drop-in configs copied into mkosi-kernel's mkosi.conf.d/ at build time. 99-vfs.conf enables selftest and fstests build profiles, sets RAM/CPU limits for QEMU, and configures the kernel command line. 99-vfs-fstests.conf activates the fstests profile and maps the xfstests source tree. 99-vfs-ovl.conf adds an ExtraTrees entry to install the unionmount-testsuite into the image.
• mkosi.kernel.config -- Kernel config fragment enabling VFS debug options (CONFIG_DEBUG_VFS, CONFIG_PROVE_LOCKING, CONFIG_XFS_DEBUG, CONFIG_BTRFS_DEBUG, CONFIG_BTRFS_ASSERT, etc.) along with a comprehensive set of filesystem, block, and networking options needed by the test suites.
• mkosi.repart/ -- Partition layout: 10G root, 5G swap, and four 2G partitions (fsdevel1..fsdevel4) used as test/scratch devices by fstests.
• mkosi.extra/ -- Files overlaid into the image: systemd service units for each test suite, test runner scripts under /usr/lib/vfs-ci/, network configuration, and userdb entries.

Running locally

scripts/local-test.sh <kernel-source-dir> [distro] [selftests|xfstests|ovl-fstests]

Examples:

scripts/local-test.sh ~/src/linux fedora selftests
scripts/local-test.sh ~/src/linux debian xfstests
scripts/local-test.sh ~/src/linux fedora           # runs all suites

Requires mkosi and b4 installed. The script clones mkosi-kernel and xfstests to /tmp on first run (override with MKOSI_KERNEL and MKOSI_FSTESTS environment variables).

Repository layout

.github/
  scripts/matrix.py          # CI matrix generator
  workflows/
    bridge.yml               # ml2pr scheduled workflow
    kernel-build-test.yml    # reusable build+test job
    sync.yml                 # kernel.org mirror sync
    test.yml                 # CI entry point
ci/mkosi/
  mkosi.conf.d/              # mkosi drop-in configs
  mkosi.kernel.config        # kernel config fragment
  mkosi.repart/              # disk partition definitions
  mkosi.extra/               # files overlaid into the image
    usr/lib/systemd/system/  # test runner service units
    usr/lib/vfs-ci/          # test runner scripts
scripts/
  local-test.sh              # run the CI locally
  ml2pr.mjs                  # mailing list to PR bridge
package.json                 # npm deps (octokit for ml2pr)