Change how btrfstree.TreePath generations work

1 files changed, 17 insertions, 18 deletions

diff --git a/lib/btrfs/btrfstree/path.go b/lib/btrfs/btrfstree/path.go
index 4a4d66e..212b5df 100644
--- a/lib/btrfs/btrfstree/path.go
+++ b/lib/btrfs/btrfstree/path.go
@@ -27,53 +27,48 @@ import (
 //
 //	[superblock: tree=B, lvl=3, gen=6]
 //	     |
-//	     | <------------------------------------------ pathElem={from_tree:B, from_gen=6, from_idx=-1,
-//	     |                                                       to_addr:0x01, to_lvl=3}
+//	     | <------------------------------------------ pathElem={from_tree:B, from_idx=-1,
+//	     |                                                       to_addr:0x01, to_gen=6, to_lvl=3}
 //	  +[0x01]-------------+
 //	  | lvl=3 gen=6 own=B |
 //	  +-+-+-+-+-+-+-+-+-+-+
 //	  |0|1|2|3|4|5|6|7|8|9|
 //	  +-+-+-+-+-+-+-+-+-+-+
 //	                 |
-//	                 | <------------------------------ pathElem:{from_tree:B, from_gen:6, from_idx:7,
-//	                 |                                           to_addr:0x02, to_lvl:2}
+//	                 | <------------------------------ pathElem:{from_tree:B, from_idx:7,
+//	                 |                                           to_addr:0x02, to_gen:5, to_lvl:2}
 //	              +[0x02]--------------+
 //	              | lvl=2 gen=5 own=B  |
 //	              +-+-+-+-+-+-+-+-+-+-+
 //	              |0|1|2|3|4|5|6|7|8|9|
 //	              +-+-+-+-+-+-+-+-+-+-+
 //	                           |
-//	                           | <-------------------- pathElem={from_tree:B, from_gen:5, from_idx:6,
-//	                           |                                 to_addr:0x03, to_lvl:1}
+//	                           | <-------------------- pathElem={from_tree:B, from_idx:6,
+//	                           |                                 to_addr:0x03, to_gen:5, to_lvl:1}
 //	                        +[0x03]-------------+
 //	                        | lvl=1 gen=5 own=A |
 //	                        +-+-+-+-+-+-+-+-+-+-+
 //	                        |0|1|2|3|4|5|6|7|8|9|
 //	                        +-+-+-+-+-+-+-+-+-+-+
 //	                               |
-//	                               | <---------------- pathElem={from_tree:A, from_gen:5, from_idx:3,
-//	                               |                             to_addr:0x04, to_lvl:0}
+//	                               | <---------------- pathElem={from_tree:A, from_idx:3,
+//	                               |                             to_addr:0x04, to_gen:2, lvl:0}
 //	                             +[0x04]-------------+
 //	                             | lvl=0 gen=2 own=A |
 //	                             +-+-+-+-+-+-+-+-+-+-+
 //	                             |0|1|2|3|4|5|6|7|8|9|
 //	                             +-+-+-+-+-+-+-+-+-+-+
 //	                                |
-//	                                | <--------------- pathElem={from_tree:A, from_gen:2, from_idx:1,
-//	                                |                            to_addr:0, to_lvl:0}
+//	                                | <--------------- pathElem={from_tree:A, from_idx:1,
+//	                                |                            to_addr:0, to_gen: 0, to_lvl:0}
 //	                              [item]
 type TreePath []TreePathElem
 
-// A TreePathElem essentially represents a KeyPointer.  If there is an
-// error looking up the tree root, everything but FromTree is zero.
+// A TreePathElem essentially represents a KeyPointer.
 type TreePathElem struct {
 	// FromTree is the owning tree ID of the parent node; or the
 	// well-known tree ID if this is the root.
 	FromTree btrfsprim.ObjID
-	// FromGeneration is the generation of the parent node the
-	// parent node; or generation stored in the superblock if this
-	// is the root.
-	FromGeneration btrfsprim.Generation
 	// FromItemIdx is the index of this KeyPointer in the parent
 	// Node; or -1 if this is the root and there is no KeyPointer.
 	FromItemIdx int
@@ -82,7 +77,11 @@ type TreePathElem struct {
 	// points at, or 0 if this is a leaf item and nothing is being
 	// pointed at.
 	ToNodeAddr btrfsvol.LogicalAddr
-	// ToNodeLevel is the expected or actual level of the node at
+	// ToNodeGeneration is the expected generation of the node at
+	// ToNodeAddr, or 0 if this is a leaf item and nothing is
+	// being pointed at.
+	ToNodeGeneration btrfsprim.Generation
+	// ToNodeLevel is the expected level of the node at
 	// ToNodeAddr, or 0 if this is a leaf item and nothing is
 	// being pointed at.
 	ToNodeLevel uint8
@@ -98,7 +97,7 @@ func (path TreePath) String() string {
 	} else {
 		var ret strings.Builder
 		fmt.Fprintf(&ret, "%s->", path[0].FromTree.Format(btrfsitem.ROOT_ITEM_KEY))
-		if len(path) == 1 && path[0] == (TreePathElem{FromTree: path[0].FromTree}) {
+		if len(path) == 1 && path[0] == (TreePathElem{FromTree: path[0].FromTree, FromItemIdx: -1}) {
 			ret.WriteString("(empty-path)")
 		} else {
 			path[0].writeNodeTo(&ret)