vendor: update buildkit to 8effd45b

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/moby/sys/mount/mount_unix.go

@@ -0,0 +1,87 @@
+// +build !darwin,!windows
+
+package mount
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/moby/sys/mountinfo"
+	"golang.org/x/sys/unix"
+)
+
+// Mount will mount filesystem according to the specified configuration.
+// Options must be specified like the mount or fstab unix commands:
+// "opt1=val1,opt2=val2". See flags.go for supported option flags.
+func Mount(device, target, mType, options string) error {
+	flag, data := parseOptions(options)
+	return mount(device, target, mType, uintptr(flag), data)
+}
+
+// Unmount lazily unmounts a filesystem on supported platforms, otherwise does
+// a normal unmount. If target is not a mount point, no error is returned.
+func Unmount(target string) error {
+	err := unix.Unmount(target, mntDetach)
+	if err == nil || err == unix.EINVAL {
+		// Ignore "not mounted" error here. Note the same error
+		// can be returned if flags are invalid, so this code
+		// assumes that the flags value is always correct.
+		return nil
+	}
+
+	return &mountError{
+		op:     "umount",
+		target: target,
+		flags:  uintptr(mntDetach),
+		err:    err,
+	}
+}
+
+// RecursiveUnmount unmounts the target and all mounts underneath, starting
+// with the deepest mount first. The argument does not have to be a mount
+// point itself.
+func RecursiveUnmount(target string) error {
+	// Fast path, works if target is a mount point that can be unmounted.
+	// On Linux, mntDetach flag ensures a recursive unmount.  For other
+	// platforms, if there are submounts, we'll get EBUSY (and fall back
+	// to the slow path). NOTE we do not ignore EINVAL here as target might
+	// not be a mount point itself (but there can be mounts underneath).
+	if err := unix.Unmount(target, mntDetach); err == nil {
+		return nil
+	}
+
+	// Slow path: get all submounts, sort, unmount one by one.
+	mounts, err := mountinfo.GetMounts(mountinfo.PrefixFilter(target))
+	if err != nil {
+		return err
+	}
+
+	// Make the deepest mount be first
+	sort.Slice(mounts, func(i, j int) bool {
+		return len(mounts[i].Mountpoint) > len(mounts[j].Mountpoint)
+	})
+
+	var (
+		suberr    error
+		lastMount = len(mounts) - 1
+	)
+	for i, m := range mounts {
+		err = Unmount(m.Mountpoint)
+		if err != nil {
+			if i == lastMount {
+				if suberr != nil {
+					return fmt.Errorf("%w (possible cause: %s)", err, suberr)
+				}
+				return err
+			}
+			// This is a submount, we can ignore the error for now,
+			// the final unmount will fail if this is a real problem.
+			// With that in mind, the _first_ failed unmount error
+			// might be the real error cause, so let's keep it.
+			if suberr == nil {
+				suberr = err
+			}
+		}
+	}
+	return nil
+}