Review round 1 on PR #194: - The edit lock did not exclude other processes (also on main): unlock removes the lock file, so a waiter could wake holding a flock on the orphaned inode while the next caller locked a fresh file. flockFile now re-checks after flock that the locked file is still the one at the path (brainfs LockIsCurrent) and retries otherwise; OpenLock reports a lock replaced mid-open as ErrLockChanged, which is retried instead of failing the edit. New cross-process test (3 re-executed processes x 400 rounds, O_EXCL marker under the lock): 0 overlaps; red without the re-check. - OpenLock unit test: relative dangling link (only the Lstat pre-check stops it; os.Root refuses absolute links on its own), live link, FIFO, directory, behind a symlinked dir, unclean path, positive control. - Rollback test: a symlink swapped in for the note before the rollback (test seam beforeStampHook) is refused, target untouched in and outside the brain. - The in-brain dangling-lock case uses a relative link and asserts the refusal names the lock. OpenLock reuses #189's RealParent; RemoveLock is dropped for brainfs.Remove. The doc comment names the swap residual. Rebased onto main after #189. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
83 lines
2.5 KiB
Go
83 lines
2.5 KiB
Go
package notes
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import (
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"errors"
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"fmt"
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"os"
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"os/exec"
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"path/filepath"
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"strconv"
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"strings"
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"testing"
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"github.com/stretchr/testify/require"
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)
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// lockChild runs inside a re-executed test binary: it takes the note's edit
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// lock N times and, while holding it, creates an O_EXCL marker. Finding the
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// marker already there means another process holds the "same" lock: mutual
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// exclusion failed. It prints the overlap count.
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func lockChild(brainDir string, rounds int) {
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t, err := Resolve(brainDir, "wiki/w/facts/n.md", ScopeNotes)
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if err != nil {
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fmt.Println("resolve:", err)
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os.Exit(2)
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}
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marker := filepath.Join(brainDir, "marker")
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overlaps := 0
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for i := 0; i < rounds; i++ {
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unlock, err := flockFile(t)
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if err != nil {
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fmt.Println("lock:", err)
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os.Exit(2)
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}
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f, err := os.OpenFile(marker, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0o644)
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if errors.Is(err, os.ErrExist) {
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overlaps++
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} else if err == nil {
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_ = f.Close()
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_ = os.Remove(marker)
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}
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unlock()
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}
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fmt.Println(overlaps)
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os.Exit(0)
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}
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func TestMain(m *testing.M) {
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if dir := os.Getenv("NOTES_LOCK_CHILD"); dir != "" {
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n, _ := strconv.Atoi(os.Getenv("NOTES_LOCK_ROUNDS"))
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lockChild(dir, n)
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}
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os.Exit(m.Run())
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}
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// hyperguild#192: the edit lock must exclude other processes (two ingestion
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// pods share the hostPath brain during a RollingUpdate). Unlock removes the
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// lock file, so without re-checking that the locked file is still the one at
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// the path, a waiter and the next caller each held a lock (measured on main:
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// hundreds of overlaps in 2000 rounds).
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func TestEditLockExcludesOtherProcesses(t *testing.T) {
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brain := t.TempDir()
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require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki", "w", "facts"), 0o755))
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require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "w", "facts", "n.md"), []byte("x"), 0o644))
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const procs, rounds = 3, 400
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cmds := make([]*exec.Cmd, procs)
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outs := make([]*strings.Builder, procs)
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for i := range cmds {
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outs[i] = &strings.Builder{}
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cmds[i] = exec.Command(os.Args[0], "-test.run=^$")
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cmds[i].Env = append(os.Environ(), "NOTES_LOCK_CHILD="+brain, "NOTES_LOCK_ROUNDS="+strconv.Itoa(rounds))
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cmds[i].Stdout, cmds[i].Stderr = outs[i], outs[i]
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require.NoError(t, cmds[i].Start())
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}
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total := 0
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for i, c := range cmds {
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require.NoError(t, c.Wait(), "child %d: %s", i, outs[i].String())
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n, err := strconv.Atoi(strings.TrimSpace(outs[i].String()))
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require.NoError(t, err, "child %d output: %q", i, outs[i].String())
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total += n
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}
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require.Zero(t, total, "processes held the edit lock at the same time")
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}
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