split files

1 files changed, 162 insertions, 0 deletions

diff --git a/lib/btrfsprogs/btrfsinspect/rebuildnodes/scan.go b/lib/btrfsprogs/btrfsinspect/rebuildnodes/scan.go
new file mode 100644
index 0000000..cd3f59e
--- /dev/null
+++ b/lib/btrfsprogs/btrfsinspect/rebuildnodes/scan.go
@@ -0,0 +1,162 @@
+// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package rebuildnodes
+
+import (
+	"context"
+
+	"github.com/datawire/dlib/dlog"
+
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
+	"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"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsinspect"
+	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
+	"git.lukeshu.com/btrfs-progs-ng/lib/maps"
+)
+
+type nodeData struct {
+	Level      uint8                // 0+1=1
+	Generation btrfsprim.Generation // 1+8=9
+	Owner      btrfsprim.ObjID      // 9+8=17
+	MinItem    btrfsprim.Key        // 17+17=34
+	MaxItem    btrfsprim.Key        // 34+17=51
+}
+
+type kpData struct {
+	From, To   btrfsvol.LogicalAddr // 0+(2*8)=16
+	Key        btrfsprim.Key        // 16+17=33
+	Generation btrfsprim.Generation // 33+8=41
+}
+
+type nodeGraph struct {
+	Nodes     map[btrfsvol.LogicalAddr]nodeData
+	EdgesFrom map[btrfsvol.LogicalAddr][]*kpData
+	EdgesTo   map[btrfsvol.LogicalAddr][]*kpData
+}
+
+type scanResult struct {
+	uuidMap
+	nodeGraph
+}
+
+func ScanDevices(ctx context.Context, fs *btrfs.FS, scanResults btrfsinspect.ScanDevicesResult) (*scanResult, error) {
+	dlog.Infof(ctx, "Building table of ObjID←→UUID...")
+
+	sb, err := fs.Superblock()
+	if err != nil {
+		return nil, err
+	}
+
+	lastPct := -1
+	total := countNodes(scanResults)
+	done := 0
+	progress := func() {
+		pct := int(100 * float64(done) / float64(total))
+		if pct != lastPct || done == total {
+			dlog.Infof(ctx, "... %v%% (%v/%v)",
+				pct, done, total)
+			lastPct = pct
+		}
+	}
+
+	ret := &scanResult{
+		uuidMap: uuidMap{
+			ObjID2UUID: make(map[btrfsprim.ObjID]btrfsprim.UUID),
+			UUID2ObjID: make(map[btrfsprim.UUID]btrfsprim.ObjID),
+			TreeParent: make(map[btrfsprim.ObjID]btrfsprim.UUID),
+
+			SeenTrees: make(containers.Set[btrfsprim.ObjID]),
+		},
+		nodeGraph: nodeGraph{
+			Nodes:     make(map[btrfsvol.LogicalAddr]nodeData),
+			EdgesFrom: make(map[btrfsvol.LogicalAddr][]*kpData),
+			EdgesTo:   make(map[btrfsvol.LogicalAddr][]*kpData),
+		},
+	}
+
+	// These 4 trees are mentioned directly in the superblock, so
+	// they are always seen.
+	ret.SeenTrees.Insert(btrfsprim.ROOT_TREE_OBJECTID)
+	ret.SeenTrees.Insert(btrfsprim.CHUNK_TREE_OBJECTID)
+	ret.SeenTrees.Insert(btrfsprim.TREE_LOG_OBJECTID)
+	ret.SeenTrees.Insert(btrfsprim.BLOCK_GROUP_TREE_OBJECTID)
+
+	progress()
+	for _, devResults := range scanResults {
+		for laddr := range devResults.FoundNodes {
+			nodeRef, err := btrfstree.ReadNode[btrfsvol.LogicalAddr](fs, *sb, laddr, btrfstree.NodeExpectations{
+				LAddr: containers.Optional[btrfsvol.LogicalAddr]{OK: true, Val: laddr},
+			})
+			if err != nil {
+				return nil, err
+			}
+
+			// UUID map rebuilding
+			for _, item := range nodeRef.Data.BodyLeaf {
+				switch itemBody := item.Body.(type) {
+				case btrfsitem.Root:
+					if err := maybeSet("ObjID2UUID", ret.ObjID2UUID, item.Key.ObjectID, itemBody.UUID); err != nil {
+						return nil, err
+					}
+					if itemBody.UUID != (btrfsprim.UUID{}) {
+						if err := maybeSet("UUID2ObjID", ret.UUID2ObjID, itemBody.UUID, item.Key.ObjectID); err != nil {
+							return nil, err
+						}
+					}
+					if err := maybeSet("ParentUUID", ret.TreeParent, item.Key.ObjectID, itemBody.ParentUUID); err != nil {
+						return nil, err
+					}
+					ret.SeenTrees.Insert(item.Key.ObjectID)
+				case btrfsitem.UUIDMap:
+					uuid := btrfsitem.KeyToUUID(item.Key)
+					if err := maybeSet("ObjID2UUID", ret.ObjID2UUID, itemBody.ObjID, uuid); err != nil {
+						return nil, err
+					}
+					if err := maybeSet("UUID2ObjID", ret.UUID2ObjID, uuid, itemBody.ObjID); err != nil {
+						return nil, err
+					}
+				}
+			}
+			ret.SeenTrees.Insert(nodeRef.Data.Head.Owner)
+
+			// graph building
+			ret.Nodes[laddr] = nodeData{
+				Level:      nodeRef.Data.Head.Level,
+				Generation: nodeRef.Data.Head.Generation,
+				Owner:      nodeRef.Data.Head.Owner,
+				MinItem:    func() btrfsprim.Key { k, _ := nodeRef.Data.MinItem(); return k }(),
+				MaxItem:    func() btrfsprim.Key { k, _ := nodeRef.Data.MaxItem(); return k }(),
+			}
+			for _, kp := range nodeRef.Data.BodyInternal {
+				dat := &kpData{
+					From:       laddr,
+					To:         kp.BlockPtr,
+					Key:        kp.Key,
+					Generation: kp.Generation,
+				}
+				ret.EdgesFrom[laddr] = append(ret.EdgesFrom[laddr], dat)
+				ret.EdgesTo[laddr] = append(ret.EdgesTo[laddr], dat)
+			}
+
+			done++
+			progress()
+		}
+	}
+
+	if done != total {
+		panic("should not happen")
+	}
+
+	missing := ret.missingRootItems()
+	if len(missing) > 0 {
+		dlog.Errorf(ctx, "... could not find root items for %d trees: %v", len(missing), maps.SortedKeys(missing))
+	}
+
+	dlog.Info(ctx, "... done building table")
+	return ret, nil
+}