let skinny paths get evicted

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/btrfs/btrfsprim/misc.go b/lib/btrfs/btrfsprim/misc.go
index 0ebbe19..9b3a6f8 100644
--- a/lib/btrfs/btrfsprim/misc.go
+++ b/lib/btrfs/btrfsprim/misc.go
@@ -6,6 +6,7 @@ package btrfsprim
 
 import (
 	"fmt"
+	"math"
 	"time"
 
 	"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
@@ -25,6 +26,24 @@ func (k Key) String() string {
 	return fmt.Sprintf("{%v %v %v}", k.ObjectID, k.ItemType, k.Offset)
 }
 
+var MaxKey = Key{
+	ObjectID: math.MaxUint64,
+	ItemType: math.MaxUint8,
+	Offset:   math.MaxUint64,
+}
+
+func (key Key) Mm() Key {
+	switch {
+	case key.Offset > 0:
+		key.Offset--
+	case key.ItemType > 0:
+		key.ItemType--
+	case key.ObjectID > 0:
+		key.ObjectID--
+	}
+	return key
+}
+
 func (a Key) Cmp(b Key) int {
 	if d := containers.NativeCmp(a.ObjectID, b.ObjectID); d != 0 {
 		return d