diff --git a/pkg/netns/netns_linux.go b/pkg/netns/netns_linux.go index bbcedc0f6..2c405172f 100644 --- a/pkg/netns/netns_linux.go +++ b/pkg/netns/netns_linux.go @@ -91,36 +91,45 @@ func NewNSWithName(name string) (ns.NetNS, error) { // Create the directory for mounting network namespaces // This needs to be a shared mountpoint in case it is mounted in to // other namespaces (containers) - err = os.MkdirAll(nsRunDir, 0o755) + err = makeNetnsDir(nsRunDir) if err != nil { return nil, err } - // Remount the namespace directory shared. This will fail if it is not - // already a mountpoint, so bind-mount it on to itself to "upgrade" it - // to a mountpoint. - err = unix.Mount("", nsRunDir, "none", unix.MS_SHARED|unix.MS_REC, "") + nsPath := path.Join(nsRunDir, name) + return newNSPath(nsPath) +} + +func makeNetnsDir(nsRunDir string) error { + err := os.MkdirAll(nsRunDir, 0o755) if err != nil { - if err != unix.EINVAL { - return nil, fmt.Errorf("mount --make-rshared %s failed: %q", nsRunDir, err) - } + return err + } + // Remount the namespace directory shared. This will fail with EINVAL + // if it is not already a mountpoint, so bind-mount it on to itself + // to "upgrade" it to a mountpoint. + err = unix.Mount("", nsRunDir, "none", unix.MS_SHARED|unix.MS_REC, "") + if err == nil { + return nil + } + if err != unix.EINVAL { + return fmt.Errorf("mount --make-rshared %s failed: %q", nsRunDir, err) + } - // Recursively remount /run/netns on itself. The recursive flag is - // so that any existing netns bindmounts are carried over. - err = unix.Mount(nsRunDir, nsRunDir, "none", unix.MS_BIND|unix.MS_REC, "") - if err != nil { - return nil, fmt.Errorf("mount --rbind %s %s failed: %q", nsRunDir, nsRunDir, err) - } + // Recursively remount /run/netns on itself. The recursive flag is + // so that any existing netns bindmounts are carried over. + err = unix.Mount(nsRunDir, nsRunDir, "none", unix.MS_BIND|unix.MS_REC, "") + if err != nil { + return fmt.Errorf("mount --rbind %s %s failed: %q", nsRunDir, nsRunDir, err) + } - // Now we can make it shared - err = unix.Mount("", nsRunDir, "none", unix.MS_SHARED|unix.MS_REC, "") - if err != nil { - return nil, fmt.Errorf("mount --make-rshared %s failed: %q", nsRunDir, err) - } + // Now we can make it shared + err = unix.Mount("", nsRunDir, "none", unix.MS_SHARED|unix.MS_REC, "") + if err != nil { + return fmt.Errorf("mount --make-rshared %s failed: %q", nsRunDir, err) } - nsPath := path.Join(nsRunDir, name) - return newNSPath(nsPath) + return nil } func newNSPath(nsPath string) (ns.NetNS, error) {