3 files changed, 38 insertions, 25 deletions

diff --git a/lib/btrfs/btrfstree/root.go b/lib/btrfs/btrfstree/root.go
index 12df0b2..6ec45b5 100644
--- a/lib/btrfs/btrfstree/root.go
+++ b/lib/btrfs/btrfstree/root.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -71,15 +71,18 @@ func LookupTreeRoot(fs TreeOperator, sb Superblock, treeID btrfsprim.ObjID) (*Tr
 		if err != nil {
 			return nil, err
 		}
-		rootItemBody, ok := rootItem.Body.(btrfsitem.Root)
-		if !ok {
-			return nil, fmt.Errorf("malformed ROOT_ITEM for tree %v", treeID)
+		switch rootItemBody := rootItem.Body.(type) {
+		case btrfsitem.Root:
+			return &TreeRoot{
+				TreeID:     treeID,
+				RootNode:   rootItemBody.ByteNr,
+				Level:      rootItemBody.Level,
+				Generation: rootItemBody.Generation,
+			}, nil
+		case btrfsitem.Error:
+			return nil, fmt.Errorf("malformed ROOT_ITEM for tree %v: %w", treeID, rootItemBody.Err)
+		default:
+			panic(fmt.Errorf("should not happen: ROOT_ITEM has unexpected item type: %T", rootItemBody))
 		}
-		return &TreeRoot{
-			TreeID:     treeID,
-			RootNode:   rootItemBody.ByteNr,
-			Level:      rootItemBody.Level,
-			Generation: rootItemBody.Generation,
-		}, nil
 	}
 }
diff --git a/lib/btrfs/csums.go b/lib/btrfs/csums.go
index bbd19bd..a32f090 100644
--- a/lib/btrfs/csums.go
+++ b/lib/btrfs/csums.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -56,9 +56,15 @@ func LookupCSum(fs btrfstree.TreeOperator, alg btrfssum.CSumType, laddr btrfsvol
 	if err != nil {
 		return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, err
 	}
-	body, ok := item.Body.(btrfsitem.ExtentCSum)
-	if !ok {
-		return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, fmt.Errorf("item body is %T not ExtentCSum", item.Body)
+	if item.Key.ItemType != btrfsitem.EXTENT_CSUM_KEY {
+		return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, fmt.Errorf("item type is %v, not EXTENT_CSUM", item.Key.ItemType)
+	}
+	switch body := item.Body.(type) {
+	case btrfsitem.ExtentCSum:
+		return body.SumRun, nil
+	case btrfsitem.Error:
+		return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, body.Err
+	default:
+		panic(fmt.Errorf("should not happen: EXTENT_CSUM has unexpected item type: %T", body))
 	}
-	return body.SumRun, nil
 }
diff --git a/lib/btrfs/io4_fs.go b/lib/btrfs/io4_fs.go
index d7c2770..d9c7cdb 100644
--- a/lib/btrfs/io4_fs.go
+++ b/lib/btrfs/io4_fs.go
@@ -87,13 +87,15 @@ func (sv *Subvolume) init() {
 			return
 		}
 
-		rootBody, ok := root.Body.(btrfsitem.Root)
-		if !ok {
-			sv.rootErr = fmt.Errorf("FS_TREE ROOT_ITEM has malformed body")
-			return
+		switch rootBody := root.Body.(type) {
+		case btrfsitem.Root:
+			sv.rootVal = rootBody
+		case btrfsitem.Error:
+			sv.rootErr = fmt.Errorf("FS_TREE ROOT_ITEM has malformed body: %w", rootBody.Err)
+		default:
+			panic(fmt.Errorf("should not happen: ROOT_ITEM has unexpected item type: %T", rootBody))
 		}
 
-		sv.rootVal = rootBody
 	})
 }
 
@@ -117,12 +119,14 @@ func (sv *Subvolume) LoadBareInode(inode btrfsprim.ObjID) (*BareInode, error) {
 			return
 		}
 
-		itemBody, ok := item.Body.(btrfsitem.Inode)
-		if !ok {
-			val.Errs = append(val.Errs, fmt.Errorf("malformed inode"))
-			return
+		switch itemBody := item.Body.(type) {
+		case btrfsitem.Inode:
+			val.InodeItem = &itemBody
+		case btrfsitem.Error:
+			val.Errs = append(val.Errs, fmt.Errorf("malformed inode: %w", itemBody.Err))
+		default:
+			panic(fmt.Errorf("should not happen: INODE_ITEM has unexpected item type: %T", itemBody))
 		}
-		val.InodeItem = &itemBody
 
 		return
 	})