tree-wide: Funnel all btrfstree.ReadNode[btrfsvol.LogicalAddr]() calls through btrfstree.NodeSource.ReadNode()

11 files changed, 42 insertions, 38 deletions

diff --git a/cmd/btrfs-rec/inspect/rebuildtrees/scan.go b/cmd/btrfs-rec/inspect/rebuildtrees/scan.go
index 3339270..86d3741 100644
--- a/cmd/btrfs-rec/inspect/rebuildtrees/scan.go
+++ b/cmd/btrfs-rec/inspect/rebuildtrees/scan.go
@@ -71,7 +71,7 @@ func ScanDevices(ctx context.Context, fs *btrfs.FS, nodeList []btrfsvol.LogicalA
 		if err := ctx.Err(); err != nil {
 			return ScanDevicesResult{}, err
 		}
-		node, err := btrfstree.ReadNode[btrfsvol.LogicalAddr](fs, *sb, laddr, btrfstree.NodeExpectations{
+		node, err := fs.ReadNode(ctx, laddr, btrfstree.NodeExpectations{
 			LAddr: containers.OptionalValue(laddr),
 		})
 		if err != nil {
@@ -93,7 +93,7 @@ func ScanDevices(ctx context.Context, fs *btrfs.FS, nodeList []btrfsvol.LogicalA
 	dlog.Info(ctx, "... done reading node data")
 
 	ctx = dlog.WithField(ctx, "btrfs.inspect.rebuild-trees.read.substep", "check")
-	if err := ret.Graph.FinalCheck(ctx, fs, *sb); err != nil {
+	if err := ret.Graph.FinalCheck(ctx, fs); err != nil {
 		return ScanDevicesResult{}, err
 	}
 
diff --git a/cmd/btrfs-rec/inspect_lstrees.go b/cmd/btrfs-rec/inspect_lstrees.go
index 1449a21..9639a2e 100644
--- a/cmd/btrfs-rec/inspect_lstrees.go
+++ b/cmd/btrfs-rec/inspect_lstrees.go
@@ -101,13 +101,12 @@ func init() {
 				treeErrCnt = 0
 				treeItemCnt = make(map[btrfsitem.Type]int)
 				textui.Fprintf(os.Stdout, "lost+found\n")
-				sb, _ := fs.Superblock()
 				for _, laddr := range nodeList {
 					if visitedNodes.Has(laddr) {
 						continue
 					}
 					visitedNodes.Insert(laddr)
-					node, err := btrfstree.ReadNode[btrfsvol.LogicalAddr](fs, *sb, laddr, btrfstree.NodeExpectations{
+					node, err := fs.ReadNode(ctx, laddr, btrfstree.NodeExpectations{
 						LAddr: containers.OptionalValue(laddr),
 					})
 					if err != nil {
diff --git a/lib/btrfs/btrfstree/btree.go b/lib/btrfs/btrfstree/btree.go
index bc1bac2..dde485a 100644
--- a/lib/btrfs/btrfstree/btree.go
+++ b/lib/btrfs/btrfstree/btree.go
@@ -11,6 +11,7 @@ import (
 	"fmt"
 
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
 )
 
 type TreeSearcher interface {
@@ -96,5 +97,5 @@ func (e *TreeError) Error() string {
 
 type NodeSource interface {
 	Superblock() (*Superblock, error)
-	ReadNode(Path) (*Node, error)
+	ReadNode(ctx context.Context, addr btrfsvol.LogicalAddr, exp NodeExpectations) (*Node, error)
 }
diff --git a/lib/btrfs/btrfstree/btree_forrest.go b/lib/btrfs/btrfstree/btree_forrest.go
index b017888..b04bfc0 100644
--- a/lib/btrfs/btrfstree/btree_forrest.go
+++ b/lib/btrfs/btrfstree/btree_forrest.go
@@ -83,7 +83,10 @@ func LookupTreeRoot(_ context.Context, fs TreeOperator, sb Superblock, treeID bt
 }
 
 type TreeOperatorImpl struct {
-	NodeSource NodeSource
+	NodeSource interface {
+		NodeSource
+		NodeFile
+	}
 }
 
 func (fs TreeOperatorImpl) RawTree(ctx context.Context, treeID btrfsprim.ObjID) (*RawTree, error) {
diff --git a/lib/btrfs/btrfstree/btree_tree.go b/lib/btrfs/btrfstree/btree_tree.go
index 89b4c52..a6311f9 100644
--- a/lib/btrfs/btrfstree/btree_tree.go
+++ b/lib/btrfs/btrfstree/btree_tree.go
@@ -22,6 +22,9 @@ type RawTree struct {
 }
 
 func (tree *RawTree) TreeWalk(ctx context.Context, cbs TreeWalkHandler) {
+	if tree.RootNode == 0 {
+		return
+	}
 	path := Path{{
 		FromTree:         tree.ID,
 		FromItemSlot:     -1,
@@ -37,12 +40,13 @@ func (tree *RawTree) walk(ctx context.Context, path Path, cbs TreeWalkHandler) {
 	if ctx.Err() != nil {
 		return
 	}
-	if path.Node(-1).ToNodeAddr == 0 {
-		return
-	}
 
 	// 001
-	node, err := tree.Forrest.NodeSource.ReadNode(path)
+	nodeAddr, nodeExp, ok := path.NodeExpectations(tree.Forrest.NodeSource)
+	if !ok {
+		return
+	}
+	node, err := tree.Forrest.NodeSource.ReadNode(ctx, nodeAddr, nodeExp)
 	defer node.Free()
 	if ctx.Err() != nil {
 		return
diff --git a/lib/btrfs/btrfstree/readnode.go b/lib/btrfs/btrfstree/readnode.go
index ac82c62..a4ccf10 100644
--- a/lib/btrfs/btrfstree/readnode.go
+++ b/lib/btrfs/btrfstree/readnode.go
@@ -14,8 +14,7 @@ import (
 )
 
 type NodeFile interface {
-	diskio.File[btrfsvol.LogicalAddr]
-	Superblock() (*Superblock, error)
+	diskio.ReaderAt[btrfsvol.LogicalAddr]
 
 	// ParentTree, given a tree ID, returns that tree's parent
 	// tree, if it has one.
@@ -29,15 +28,14 @@ type NodeFile interface {
 	ParentTree(btrfsprim.ObjID) (btrfsprim.ObjID, btrfsprim.Generation, bool)
 }
 
-// FSReadNode is a utility function to help with implementing the
-// 'NodeSource' interface.
-func FSReadNode(
-	fs NodeFile,
-	path Path,
-) (*Node, error) {
-	sb, err := fs.Superblock()
-	if err != nil {
-		return nil, fmt.Errorf("btrfs.FS.ReadNode: %w", err)
+// NodeExpectations returns the address to read and the expectations
+// to have when reading the node pointed to by this Path.
+//
+// `ok` is false if the path is empty or if this Path points to an
+// item rather than a node.
+func (path Path) NodeExpectations(fs NodeFile) (_ btrfsvol.LogicalAddr, _ NodeExpectations, ok bool) {
+	if path.Node(-1).ToNodeAddr == 0 && path.Node(-1).ToNodeGeneration == 0 && path.Node(-1).ToNodeLevel == 0 {
+		return 0, NodeExpectations{}, false
 	}
 
 	checkOwner := func(owner btrfsprim.ObjID, gen btrfsprim.Generation) error {
@@ -70,12 +68,12 @@ func FSReadNode(
 		}
 	}
 
-	return ReadNode[btrfsvol.LogicalAddr](fs, *sb, path.Node(-1).ToNodeAddr, NodeExpectations{
+	return path.Node(-1).ToNodeAddr, NodeExpectations{
 		LAddr:      containers.OptionalValue(path.Node(-1).ToNodeAddr),
 		Level:      containers.OptionalValue(path.Node(-1).ToNodeLevel),
 		Generation: containers.OptionalValue(path.Node(-1).ToNodeGeneration),
 		Owner:      checkOwner,
 		MinItem:    containers.OptionalValue(path.Node(-1).ToKey),
 		MaxItem:    containers.OptionalValue(path.Node(-1).ToMaxKey),
-	})
+	}, true
 }
diff --git a/lib/btrfs/io3_btree.go b/lib/btrfs/io3_btree.go
index f1436fb..bb68d7d 100644
--- a/lib/btrfs/io3_btree.go
+++ b/lib/btrfs/io3_btree.go
@@ -6,10 +6,12 @@ package btrfs
 
 import (
 	"context"
+	"fmt"
 
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem"
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfstree"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
 )
 
 // This file is ordered from low-level to high-level.
@@ -79,8 +81,12 @@ var _ btrfstree.NodeFile = (*FS)(nil)
 // btrfstree.NodeSource ////////////////////////////////////////////////////////
 
 // ReadNode implements btrfstree.NodeSource.
-func (fs *FS) ReadNode(path btrfstree.Path) (*btrfstree.Node, error) {
-	return btrfstree.FSReadNode(fs, path)
+func (fs *FS) ReadNode(_ context.Context, addr btrfsvol.LogicalAddr, exp btrfstree.NodeExpectations) (*btrfstree.Node, error) {
+	sb, err := fs.Superblock()
+	if err != nil {
+		return nil, fmt.Errorf("btrfs.FS.ReadNode: %w", err)
+	}
+	return btrfstree.ReadNode[btrfsvol.LogicalAddr](fs, *sb, addr, exp)
 }
 
 var _ btrfstree.NodeSource = (*FS)(nil)
diff --git a/lib/btrfsutil/graph.go b/lib/btrfsutil/graph.go
index 39e1cf2..4148f89 100644
--- a/lib/btrfsutil/graph.go
+++ b/lib/btrfsutil/graph.go
@@ -17,7 +17,6 @@ import (
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfstree"
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
 	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
-	"git.lukeshu.com/btrfs-progs-ng/lib/diskio"
 	"git.lukeshu.com/btrfs-progs-ng/lib/maps"
 	"git.lukeshu.com/btrfs-progs-ng/lib/slices"
 	"git.lukeshu.com/btrfs-progs-ng/lib/textui"
@@ -199,7 +198,7 @@ func (g Graph) InsertNode(node *btrfstree.Node) {
 	}
 }
 
-func (g Graph) FinalCheck(ctx context.Context, fs diskio.File[btrfsvol.LogicalAddr], sb btrfstree.Superblock) error {
+func (g Graph) FinalCheck(ctx context.Context, fs btrfstree.NodeSource) error {
 	var stats textui.Portion[int]
 
 	dlog.Info(ctx, "Checking keypointers for dead-ends...")
@@ -208,7 +207,7 @@ func (g Graph) FinalCheck(ctx context.Context, fs diskio.File[btrfsvol.LogicalAd
 	progressWriter.Set(stats)
 	for laddr := range g.EdgesTo {
 		if _, ok := g.Nodes[laddr]; !ok {
-			_, err := btrfstree.ReadNode[btrfsvol.LogicalAddr](fs, sb, laddr, btrfstree.NodeExpectations{
+			_, err := fs.ReadNode(ctx, laddr, btrfstree.NodeExpectations{
 				LAddr: containers.OptionalValue(laddr),
 			})
 			if err == nil {
diff --git a/lib/btrfsutil/old_rebuilt_forrest.go b/lib/btrfsutil/old_rebuilt_forrest.go
index 5b99892..24faf79 100644
--- a/lib/btrfsutil/old_rebuilt_forrest.go
+++ b/lib/btrfsutil/old_rebuilt_forrest.go
@@ -231,12 +231,7 @@ func (tree oldRebuiltTree) addErrs(fn func(btrfsprim.Key, uint32) int, err error
 }
 
 func (bt *OldRebuiltForrest) readNode(nodeInfo nodeInfo) *btrfstree.Node {
-	sb, err := bt.inner.Superblock()
-	if err != nil {
-		panic(fmt.Errorf("should not happen: i/o error: %w", err))
-	}
-
-	node, err := btrfstree.ReadNode[btrfsvol.LogicalAddr](bt.inner, *sb, nodeInfo.LAddr, btrfstree.NodeExpectations{
+	node, err := bt.inner.ReadNode(bt.ctx, nodeInfo.LAddr, btrfstree.NodeExpectations{
 		LAddr:      containers.OptionalValue(nodeInfo.LAddr),
 		Level:      containers.OptionalValue(nodeInfo.Level),
 		Generation: containers.OptionalValue(nodeInfo.Generation),
diff --git a/lib/btrfsutil/rebuilt_forrest.go b/lib/btrfsutil/rebuilt_forrest.go
index 811e1ac..4f7a24b 100644
--- a/lib/btrfsutil/rebuilt_forrest.go
+++ b/lib/btrfsutil/rebuilt_forrest.go
@@ -15,7 +15,6 @@ import (
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfstree"
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
 	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
-	"git.lukeshu.com/btrfs-progs-ng/lib/diskio"
 	"git.lukeshu.com/btrfs-progs-ng/lib/slices"
 	"git.lukeshu.com/btrfs-progs-ng/lib/textui"
 )
@@ -130,7 +129,7 @@ func (cb noopRebuiltForrestCallbacks) LookupUUID(ctx context.Context, uuid btrfs
 // NewRebuiltForrest().
 type RebuiltForrest struct {
 	// static
-	file  diskio.File[btrfsvol.LogicalAddr]
+	file  btrfstree.NodeSource
 	sb    btrfstree.Superblock
 	graph Graph
 	cb    RebuiltForrestCallbacks
@@ -148,7 +147,7 @@ type RebuiltForrest struct {
 
 // NewRebuiltForrest returns a new RebuiltForrest instance.  The
 // RebuiltForrestCallbacks may be nil.
-func NewRebuiltForrest(file diskio.File[btrfsvol.LogicalAddr], sb btrfstree.Superblock, graph Graph, cb RebuiltForrestCallbacks) *RebuiltForrest {
+func NewRebuiltForrest(file btrfstree.NodeSource, sb btrfstree.Superblock, graph Graph, cb RebuiltForrestCallbacks) *RebuiltForrest {
 	ret := &RebuiltForrest{
 		file:  file,
 		sb:    sb,
diff --git a/lib/btrfsutil/rebuilt_readitem.go b/lib/btrfsutil/rebuilt_readitem.go
index d3a2253..2520593 100644
--- a/lib/btrfsutil/rebuilt_readitem.go
+++ b/lib/btrfsutil/rebuilt_readitem.go
@@ -34,7 +34,7 @@ func (ts *RebuiltForrest) readNode(ctx context.Context, laddr btrfsvol.LogicalAd
 		panic(fmt.Errorf("should not happen: node@%v is not mentioned in the in-memory graph", laddr))
 	}
 
-	node, err := btrfstree.ReadNode[btrfsvol.LogicalAddr](ts.file, ts.sb, laddr, btrfstree.NodeExpectations{
+	node, err := ts.file.ReadNode(ctx, laddr, btrfstree.NodeExpectations{
 		LAddr:      containers.OptionalValue(laddr),
 		Level:      containers.OptionalValue(graphInfo.Level),
 		Generation: containers.OptionalValue(graphInfo.Generation),