return response.err
}
+func (v *UnixVolume) Touch(loc string) error {
+ p := v.blockPath(loc)
+ f, err := os.OpenFile(p, os.O_RDWR|os.O_APPEND, 0644)
+ if err != nil {
+ return err
+ }
+ if e := lockfile(f); e != nil {
+ return e
+ }
+ defer unlockfile(f)
+ now := time.Now().Unix()
+ utime := syscall.Utimbuf{now, now}
+ return syscall.Utime(p, &utime)
+}
+
+func (v *UnixVolume) Mtime(loc string) (time.Time, error) {
+ p := v.blockPath(loc)
+ if fi, err := os.Stat(p); err != nil {
+ return time.Time{}, err
+ } else {
+ return fi.ModTime(), nil
+ }
+}
+
// Read retrieves a block identified by the locator string "loc", and
// returns its contents as a byte slice.
//
}
func (v *UnixVolume) Delete(loc string) error {
- return os.Remove(v.blockPath(loc))
+ p := v.blockPath(loc)
+ f, err := os.OpenFile(p, os.O_RDWR|os.O_APPEND, 0644)
+ if err != nil {
+ return err
+ }
+ if e := lockfile(f); e != nil {
+ return e
+ }
+ defer unlockfile(f)
+
+ // If the block has been PUT more recently than -permission_ttl,
+ // return success without removing the block. This guards against
+ // a race condition where a block is old enough that Data Manager
+ // has added it to the trash list, but the user submitted a PUT
+ // for the block since then.
+ if fi, err := os.Stat(p); err != nil {
+ return err
+ } else {
+ if time.Since(fi.ModTime()) < permission_ttl {
+ return nil
+ }
+ }
+ return os.Remove(p)
}
// blockDir returns the fully qualified directory name for the directory
func (v *UnixVolume) String() string {
return fmt.Sprintf("[UnixVolume %s]", v.root)
}
+
+// lockfile and unlockfile use flock(2) to manage kernel file locks.
+func lockfile(f *os.File) error {
+ return syscall.Flock(int(f.Fd()), syscall.LOCK_EX)
+}
+
+func unlockfile(f *os.File) error {
+ return syscall.Flock(int(f.Fd()), syscall.LOCK_UN)
+}