task a8: move all binaries under ./cmd/<name>/main.go

Relocates the two non-canonical main packages so every binary in the repo
lives at ./cmd/<BINARY>/main.go:

- tools/filewriter/ -> cmd/filewriter/
- integrationtests/cmd/ioworkload/ (20 files) -> cmd/ioworkload/

Consumers updated:
- Magefile.go: workloadSourcePath now ./cmd/ioworkload
- integrationtests/README.md: structure note points at ../cmd/ioworkload

Files moved with git mv so git log --follow history is preserved.
cmd/ior/main.go was already canonical and is untouched.

Verified: mage build produces the ior binary; go build ./cmd/...
builds filewriter and ioworkload; go test ./cmd/ioworkload passes;
go vet ./cmd/filewriter ./cmd/ioworkload is clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

1 files changed, 0 insertions, 93 deletions

diff --git a/integrationtests/cmd/ioworkload/scenario_truncate.go b/integrationtests/cmd/ioworkload/scenario_truncate.go
deleted file mode 100644
index 04288d5..0000000
--- a/integrationtests/cmd/ioworkload/scenario_truncate.go
+++ /dev/null
@@ -1,93 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"path/filepath"
-	"runtime"
-	"syscall"
-	"unsafe"
-)
-
-// truncateBasic opens a file, writes data, then truncates it via
-// syscall.Truncate which uses SYS_TRUNCATE directly on amd64 (path-based).
-func truncateBasic() error {
-	dir, cleanup, err := makeTempDir("truncate-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "truncfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-
-	if _, err := syscall.Write(fd, []byte("truncate this content")); err != nil {
-		syscall.Close(fd)
-		return fmt.Errorf("write: %w", err)
-	}
-	syscall.Close(fd)
-
-	return syscall.Truncate(path, 5)
-}
-
-// truncateFtruncate opens a file, writes data, then truncates it via
-// syscall.Ftruncate which uses SYS_FTRUNCATE directly on amd64 (fd-based).
-func truncateFtruncate() error {
-	dir, cleanup, err := makeTempDir("truncate-ftruncate")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "ftruncfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	if _, err := syscall.Write(fd, []byte("ftruncate this content")); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-	return syscall.Ftruncate(fd, 5)
-}
-
-// truncateEnoent attempts to truncate a nonexistent file via raw SYS_TRUNCATE.
-// The syscall fails with ENOENT, but ior captures the enter_truncate
-// tracepoint because the path is read on entry.
-func truncateEnoent() error {
-	dir, cleanup, err := makeTempDir("truncate-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "truncate-enoent-missing.txt")
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	// Retry a few times to make this test resilient under high integration
-	// parallelism where a single failed syscall event can be dropped.
-	for i := 0; i < 5; i++ {
-		_, _, errno := syscall.Syscall(syscall.SYS_TRUNCATE, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
-		runtime.KeepAlive(pathBytes)
-		if errno == 0 {
-			return fmt.Errorf("expected ENOENT, but truncate succeeded")
-		}
-	}
-	return nil
-}
-
-// truncateFtruncateEbadf calls raw SYS_FTRUNCATE on an invalid fd (99999).
-// The syscall fails with EBADF, but ior captures the enter_ftruncate
-// tracepoint because it is recorded on syscall entry.
-func truncateFtruncateEbadf() error {
-	_, _, errno := syscall.Syscall(syscall.SYS_FTRUNCATE, 99999, 0, 0)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but ftruncate succeeded")
-	}
-	return nil
-}