check for bad items

Big indentation change in print_tree.go; small actual change.

3 files changed, 273 insertions, 258 deletions

diff --git a/lib/btrfs/btrfsitem/items.go b/lib/btrfs/btrfsitem/items.go
index 30980d3..769a0a8 100644
--- a/lib/btrfs/btrfsitem/items.go
+++ b/lib/btrfs/btrfsitem/items.go
@@ -35,7 +35,7 @@ func (o *Error) UnmarshalBinary(dat []byte) (int, error) {
 	return len(dat), nil
 }
 
-// Rather than returning a separate error  value, return an Error item.
+// Rather than returning a separate error value, return an Error item.
 func UnmarshalItem(key internal.Key, csumType btrfssum.CSumType, dat []byte) Item {
 	var gotyp reflect.Type
 	if key.ItemType == UNTYPED_KEY {
diff --git a/lib/btrfs/io3_btree.go b/lib/btrfs/io3_btree.go
index 759e378..a02a857 100644
--- a/lib/btrfs/io3_btree.go
+++ b/lib/btrfs/io3_btree.go
@@ -208,7 +208,8 @@ type TreeWalkHandler struct {
 	PreKeyPointer  func(TreePath, KeyPointer) error
 	PostKeyPointer func(TreePath, KeyPointer) error
 	// Callbacks for items on leaf nodes
-	Item func(TreePath, Item) error
+	Item    func(TreePath, Item) error
+	BadItem func(TreePath, Item) error
 }
 
 // The lifecycle of callbacks is:
@@ -222,7 +223,7 @@ type TreeWalkHandler struct {
 //     005     (recurse)
 //     006     .PostKeyPointer()
 //           else:
-//     004     .Item()
+//     004     .Item() (or .BadItem())
 //     007 .PostNode()
 func (fs *FS) TreeWalk(treeID ObjID, errHandle func(*TreeError), cbs TreeWalkHandler) {
 	path := TreePath{
@@ -259,8 +260,10 @@ func (fs *FS) treeWalk(path TreePath, errHandle func(*TreeError), cbs TreeWalkHa
 	if err != nil {
 		errHandle(&TreeError{Path: path, Err: err})
 	} else {
-		if err := cbs.Node(path, node); err != nil {
-			errHandle(&TreeError{Path: path, Err: err})
+		if cbs.Node != nil {
+			if err := cbs.Node(path, node); err != nil {
+				errHandle(&TreeError{Path: path, Err: err})
+			}
 		}
 	}
 	if node != nil {
@@ -272,23 +275,33 @@ func (fs *FS) treeWalk(path TreePath, errHandle func(*TreeError), cbs TreeWalkHa
 			})
 			if cbs.PreKeyPointer != nil {
 				if err := cbs.PreKeyPointer(itemPath, item); err != nil {
-					errHandle(&TreeError{Path: path, Err: err})
+					errHandle(&TreeError{Path: itemPath, Err: err})
 				}
 			}
 			fs.treeWalk(itemPath, errHandle, cbs)
 			if cbs.PostKeyPointer != nil {
 				if err := cbs.PostKeyPointer(itemPath, item); err != nil {
-					errHandle(&TreeError{Path: path, Err: err})
+					errHandle(&TreeError{Path: itemPath, Err: err})
 				}
 			}
 		}
 		for i, item := range node.Data.BodyLeaf {
-			if cbs.Item != nil {
-				itemPath := path.Append(TreePathElem{
-					ItemIdx: i,
-				})
-				if err := cbs.Item(itemPath, item); err != nil {
-					errHandle(&TreeError{Path: path, Err: err})
+			itemPath := path.Append(TreePathElem{
+				ItemIdx: i,
+			})
+			if errBody, isErr := item.Body.(btrfsitem.Error); isErr {
+				if cbs.BadItem == nil {
+					errHandle(&TreeError{Path: itemPath, Err: errBody.Err})
+				} else {
+					if err := cbs.BadItem(itemPath, item); err != nil {
+						errHandle(&TreeError{Path: itemPath, Err: err})
+					}
+				}
+			} else {
+				if cbs.Item != nil {
+					if err := cbs.Item(itemPath, item); err != nil {
+						errHandle(&TreeError{Path: itemPath, Err: err})
+					}
 				}
 			}
 		}
diff --git a/lib/btrfsprogs/btrfsinspect/print_tree.go b/lib/btrfsprogs/btrfsinspect/print_tree.go
index 78a9df6..2de9818 100644
--- a/lib/btrfsprogs/btrfsinspect/print_tree.go
+++ b/lib/btrfsprogs/btrfsinspect/print_tree.go
@@ -92,260 +92,262 @@ func DumpTrees(ctx context.Context, out io.Writer, fs *btrfs.FS) {
 // kernel-shared/print-tree.c:btrfs_print_leaf()
 func printTree(ctx context.Context, out io.Writer, fs *btrfs.FS, treeID btrfs.ObjID) {
 	var itemOffset uint32
-	fs.TreeWalk(
-		treeID,
-		func(err *btrfs.TreeError) {
-			dlog.Error(ctx, err)
+	handlers := btrfs.TreeWalkHandler{
+		Node: func(path btrfs.TreePath, nodeRef *util.Ref[btrfsvol.LogicalAddr, btrfs.Node]) error {
+			printHeaderInfo(out, nodeRef.Data)
+			itemOffset = nodeRef.Data.Size - uint32(binstruct.StaticSize(btrfs.NodeHeader{}))
+			return nil
 		},
-		btrfs.TreeWalkHandler{
-			Node: func(path btrfs.TreePath, nodeRef *util.Ref[btrfsvol.LogicalAddr, btrfs.Node]) error {
-				printHeaderInfo(out, nodeRef.Data)
-				itemOffset = nodeRef.Data.Size - uint32(binstruct.StaticSize(btrfs.NodeHeader{}))
-				return nil
-			},
-			PreKeyPointer: func(_ btrfs.TreePath, item btrfs.KeyPointer) error {
-				fmt.Fprintf(out, "\t%v block %v gen %v\n",
-					fmtKey(item.Key),
-					item.BlockPtr,
-					item.Generation)
-				return nil
-			},
-			Item: func(path btrfs.TreePath, item btrfs.Item) error {
-				i := path.Nodes[len(path.Nodes)-1].ItemIdx
-				bs, _ := binstruct.Marshal(item.Body)
-				itemSize := uint32(len(bs))
-				itemOffset -= itemSize
-				fmt.Fprintf(out, "\titem %v %v itemoff %v itemsize %v\n",
-					i,
-					fmtKey(item.Key),
-					itemOffset,
-					itemSize)
-				switch body := item.Body.(type) {
-				case btrfsitem.FreeSpaceHeader:
-					fmt.Fprintf(out, "\t\tlocation %v\n", fmtKey(body.Location))
-					fmt.Fprintf(out, "\t\tcache generation %v entries %v bitmaps %v\n",
-						body.Generation, body.NumEntries, body.NumBitmaps)
-				case btrfsitem.Inode:
-					fmt.Fprintf(out, ""+
-						"\t\tgeneration %v transid %v size %v nbytes %v\n"+
-						"\t\tblock group %v mode %o links %v uid %v gid %v rdev %v\n"+
-						"\t\tsequence %v flags %v\n",
-						body.Generation, body.TransID, body.Size, body.NumBytes,
-						body.BlockGroup, body.Mode, body.NLink, body.UID, body.GID, body.RDev,
-						body.Sequence, body.Flags)
-					fmt.Fprintf(out, "\t\tatime %v\n", fmtTime(body.ATime))
+		PreKeyPointer: func(_ btrfs.TreePath, item btrfs.KeyPointer) error {
+			fmt.Fprintf(out, "\t%v block %v gen %v\n",
+				fmtKey(item.Key),
+				item.BlockPtr,
+				item.Generation)
+			return nil
+		},
+		Item: func(path btrfs.TreePath, item btrfs.Item) error {
+			i := path.Nodes[len(path.Nodes)-1].ItemIdx
+			bs, _ := binstruct.Marshal(item.Body)
+			itemSize := uint32(len(bs))
+			itemOffset -= itemSize
+			fmt.Fprintf(out, "\titem %v %v itemoff %v itemsize %v\n",
+				i,
+				fmtKey(item.Key),
+				itemOffset,
+				itemSize)
+			switch body := item.Body.(type) {
+			case btrfsitem.FreeSpaceHeader:
+				fmt.Fprintf(out, "\t\tlocation %v\n", fmtKey(body.Location))
+				fmt.Fprintf(out, "\t\tcache generation %v entries %v bitmaps %v\n",
+					body.Generation, body.NumEntries, body.NumBitmaps)
+			case btrfsitem.Inode:
+				fmt.Fprintf(out, ""+
+					"\t\tgeneration %v transid %v size %v nbytes %v\n"+
+					"\t\tblock group %v mode %o links %v uid %v gid %v rdev %v\n"+
+					"\t\tsequence %v flags %v\n",
+					body.Generation, body.TransID, body.Size, body.NumBytes,
+					body.BlockGroup, body.Mode, body.NLink, body.UID, body.GID, body.RDev,
+					body.Sequence, body.Flags)
+				fmt.Fprintf(out, "\t\tatime %v\n", fmtTime(body.ATime))
+				fmt.Fprintf(out, "\t\tctime %v\n", fmtTime(body.CTime))
+				fmt.Fprintf(out, "\t\tmtime %v\n", fmtTime(body.MTime))
+				fmt.Fprintf(out, "\t\totime %v\n", fmtTime(body.OTime))
+			case btrfsitem.InodeRef:
+				fmt.Fprintf(out, "\t\tindex %v namelen %v name: %s\n",
+					body.Index, body.NameLen, body.Name)
+			//case btrfsitem.INODE_EXTREF_KEY:
+			//	// TODO
+			case btrfsitem.DirEntry:
+				fmt.Fprintf(out, "\t\tlocation %v type %v\n",
+					fmtKey(body.Location), body.Type)
+				fmt.Fprintf(out, "\t\ttransid %v data_len %v name_len %v\n",
+					body.TransID, body.DataLen, body.NameLen)
+				fmt.Fprintf(out, "\t\tname: %s\n", body.Name)
+				if len(body.Data) > 0 {
+					fmt.Fprintf(out, "\t\tdata %v\n", body.Data)
+				}
+			//case btrfsitem.DIR_LOG_INDEX_KEY, btrfsitem.DIR_LOG_ITEM_KEY:
+			//	// TODO
+			case btrfsitem.Root:
+				fmt.Fprintf(out, "\t\tgeneration %v root_dirid %v bytenr %d byte_limit %v bytes_used %v\n",
+					body.Generation, body.RootDirID, body.ByteNr, body.ByteLimit, body.BytesUsed)
+				fmt.Fprintf(out, "\t\tlast_snapshot %v flags %v refs %v\n",
+					body.LastSnapshot, body.Flags, body.Refs)
+				fmt.Fprintf(out, "\t\tdrop_progress %v drop_level %v\n",
+					fmtKey(body.DropProgress), body.DropLevel)
+				fmt.Fprintf(out, "\t\tlevel %v generation_v2 %v\n",
+					body.Level, body.GenerationV2)
+				if body.Generation == body.GenerationV2 {
+					fmt.Fprintf(out, "\t\tuuid %v\n", body.UUID)
+					fmt.Fprintf(out, "\t\tparent_uuid %v\n", body.ParentUUID)
+					fmt.Fprintf(out, "\t\treceived_uuid %v\n", body.ReceivedUUID)
+					fmt.Fprintf(out, "\t\tctransid %v otransid %v stransid %v rtransid %v\n",
+						body.CTransID, body.OTransID, body.STransID, body.RTransID)
 					fmt.Fprintf(out, "\t\tctime %v\n", fmtTime(body.CTime))
-					fmt.Fprintf(out, "\t\tmtime %v\n", fmtTime(body.MTime))
 					fmt.Fprintf(out, "\t\totime %v\n", fmtTime(body.OTime))
-				case btrfsitem.InodeRef:
-					fmt.Fprintf(out, "\t\tindex %v namelen %v name: %s\n",
-						body.Index, body.NameLen, body.Name)
-				//case btrfsitem.INODE_EXTREF_KEY:
-				//	// TODO
-				case btrfsitem.DirEntry:
-					fmt.Fprintf(out, "\t\tlocation %v type %v\n",
-						fmtKey(body.Location), body.Type)
-					fmt.Fprintf(out, "\t\ttransid %v data_len %v name_len %v\n",
-						body.TransID, body.DataLen, body.NameLen)
-					fmt.Fprintf(out, "\t\tname: %s\n", body.Name)
-					if len(body.Data) > 0 {
-						fmt.Fprintf(out, "\t\tdata %v\n", body.Data)
-					}
-				//case btrfsitem.DIR_LOG_INDEX_KEY, btrfsitem.DIR_LOG_ITEM_KEY:
-				//	// TODO
-				case btrfsitem.Root:
-					fmt.Fprintf(out, "\t\tgeneration %v root_dirid %v bytenr %d byte_limit %v bytes_used %v\n",
-						body.Generation, body.RootDirID, body.ByteNr, body.ByteLimit, body.BytesUsed)
-					fmt.Fprintf(out, "\t\tlast_snapshot %v flags %v refs %v\n",
-						body.LastSnapshot, body.Flags, body.Refs)
-					fmt.Fprintf(out, "\t\tdrop_progress %v drop_level %v\n",
-						fmtKey(body.DropProgress), body.DropLevel)
-					fmt.Fprintf(out, "\t\tlevel %v generation_v2 %v\n",
-						body.Level, body.GenerationV2)
-					if body.Generation == body.GenerationV2 {
-						fmt.Fprintf(out, "\t\tuuid %v\n", body.UUID)
-						fmt.Fprintf(out, "\t\tparent_uuid %v\n", body.ParentUUID)
-						fmt.Fprintf(out, "\t\treceived_uuid %v\n", body.ReceivedUUID)
-						fmt.Fprintf(out, "\t\tctransid %v otransid %v stransid %v rtransid %v\n",
-							body.CTransID, body.OTransID, body.STransID, body.RTransID)
-						fmt.Fprintf(out, "\t\tctime %v\n", fmtTime(body.CTime))
-						fmt.Fprintf(out, "\t\totime %v\n", fmtTime(body.OTime))
-						fmt.Fprintf(out, "\t\tstime %v\n", fmtTime(body.STime))
-						fmt.Fprintf(out, "\t\trtime %v\n", fmtTime(body.RTime))
-					}
-				case btrfsitem.RootRef:
-					var tag string
-					switch item.Key.ItemType {
-					case btrfsitem.ROOT_REF_KEY:
-						tag = "ref"
-					case btrfsitem.ROOT_BACKREF_KEY:
-						tag = "backref"
-					default:
-						tag = fmt.Sprintf("(error: unhandled RootRef item type: %v)", item.Key.ItemType)
-					}
-					fmt.Fprintf(out, "\t\troot %v key dirid %v sequence %v name %s\n",
-						tag, body.DirID, body.Sequence, body.Name)
-				case btrfsitem.Extent:
-					fmt.Fprintf(out, "\t\trefs %v gen %v flags %v\n",
-						body.Head.Refs, body.Head.Generation, body.Head.Flags)
-					if body.Head.Flags.Has(btrfsitem.EXTENT_FLAG_TREE_BLOCK) {
-						fmt.Fprintf(out, "\t\ttree block %v level %v\n",
-							fmtKey(body.Info.Key), body.Info.Level)
-					}
-					printExtentInlineRefs(out, body.Refs)
-				case btrfsitem.Metadata:
-					fmt.Fprintf(out, "\t\trefs %v gen %v flags %v\n",
-						body.Head.Refs, body.Head.Generation, body.Head.Flags)
-					fmt.Fprintf(out, "\t\ttree block skinny level %v\n", item.Key.Offset)
-					printExtentInlineRefs(out, body.Refs)
-				//case btrfsitem.EXTENT_DATA_REF_KEY:
-				//	// TODO
-				//case btrfsitem.SHARED_DATA_REF_KEY:
-				//	// TODO
-				case btrfsitem.ExtentCSum:
-					sb, _ := fs.Superblock()
-					sectorSize := btrfsvol.AddrDelta(sb.Data.SectorSize)
+					fmt.Fprintf(out, "\t\tstime %v\n", fmtTime(body.STime))
+					fmt.Fprintf(out, "\t\trtime %v\n", fmtTime(body.RTime))
+				}
+			case btrfsitem.RootRef:
+				var tag string
+				switch item.Key.ItemType {
+				case btrfsitem.ROOT_REF_KEY:
+					tag = "ref"
+				case btrfsitem.ROOT_BACKREF_KEY:
+					tag = "backref"
+				default:
+					tag = fmt.Sprintf("(error: unhandled RootRef item type: %v)", item.Key.ItemType)
+				}
+				fmt.Fprintf(out, "\t\troot %v key dirid %v sequence %v name %s\n",
+					tag, body.DirID, body.Sequence, body.Name)
+			case btrfsitem.Extent:
+				fmt.Fprintf(out, "\t\trefs %v gen %v flags %v\n",
+					body.Head.Refs, body.Head.Generation, body.Head.Flags)
+				if body.Head.Flags.Has(btrfsitem.EXTENT_FLAG_TREE_BLOCK) {
+					fmt.Fprintf(out, "\t\ttree block %v level %v\n",
+						fmtKey(body.Info.Key), body.Info.Level)
+				}
+				printExtentInlineRefs(out, body.Refs)
+			case btrfsitem.Metadata:
+				fmt.Fprintf(out, "\t\trefs %v gen %v flags %v\n",
+					body.Head.Refs, body.Head.Generation, body.Head.Flags)
+				fmt.Fprintf(out, "\t\ttree block skinny level %v\n", item.Key.Offset)
+				printExtentInlineRefs(out, body.Refs)
+			//case btrfsitem.EXTENT_DATA_REF_KEY:
+			//	// TODO
+			//case btrfsitem.SHARED_DATA_REF_KEY:
+			//	// TODO
+			case btrfsitem.ExtentCSum:
+				sb, _ := fs.Superblock()
+				sectorSize := btrfsvol.AddrDelta(sb.Data.SectorSize)
 
-					start := btrfsvol.LogicalAddr(item.Key.Offset)
-					itemSize := btrfsvol.AddrDelta(len(body.Sums)) * sectorSize
-					fmt.Fprintf(out, "\t\trange start %d end %d length %d",
-						start, start.Add(itemSize), itemSize)
-					sumsPerLine := util.Max(1, len(btrfssum.CSum{})/body.ChecksumSize/2)
+				start := btrfsvol.LogicalAddr(item.Key.Offset)
+				itemSize := btrfsvol.AddrDelta(len(body.Sums)) * sectorSize
+				fmt.Fprintf(out, "\t\trange start %d end %d length %d",
+					start, start.Add(itemSize), itemSize)
+				sumsPerLine := util.Max(1, len(btrfssum.CSum{})/body.ChecksumSize/2)
 
-					pos := start
-					for i, sum := range body.Sums {
-						if i%sumsPerLine == 0 {
-							fmt.Fprintf(out, "\n\t\t")
-						} else {
-							fmt.Fprintf(out, " ")
-						}
-						fmt.Fprintf(out, "[%d] 0x%s", pos, sum.Fmt(sb.Data.ChecksumType))
-						pos = pos.Add(sectorSize)
-					}
-					fmt.Fprintf(out, "\n")
-				case btrfsitem.FileExtent:
-					fmt.Fprintf(out, "\t\tgeneration %v type %v\n",
-						body.Generation, body.Type)
-					switch body.Type {
-					case btrfsitem.FILE_EXTENT_INLINE:
-						fmt.Fprintf(out, "\t\tinline extent data size %v ram_bytes %v compression %v\n",
-							len(body.BodyInline), body.RAMBytes, body.Compression)
-					case btrfsitem.FILE_EXTENT_PREALLOC:
-						fmt.Fprintf(out, "\t\tprealloc data disk byte %v nr %v\n",
-							body.BodyExtent.DiskByteNr,
-							body.BodyExtent.DiskNumBytes)
-						fmt.Fprintf(out, "\t\tprealloc data offset %v nr %v\n",
-							body.BodyExtent.Offset,
-							body.BodyExtent.NumBytes)
-					case btrfsitem.FILE_EXTENT_REG:
-						fmt.Fprintf(out, "\t\textent data disk byte %d nr %d\n",
-							body.BodyExtent.DiskByteNr,
-							body.BodyExtent.DiskNumBytes)
-						fmt.Fprintf(out, "\t\textent data offset %d nr %d ram %v\n",
-							body.BodyExtent.Offset,
-							body.BodyExtent.NumBytes,
-							body.RAMBytes)
-						fmt.Fprintf(out, "\t\textent compression %v\n",
-							body.Compression)
-					default:
-						fmt.Fprintf(out, "\t\t(error) unknown file extent type %v", body.Type)
+				pos := start
+				for i, sum := range body.Sums {
+					if i%sumsPerLine == 0 {
+						fmt.Fprintf(out, "\n\t\t")
+					} else {
+						fmt.Fprintf(out, " ")
 					}
-				case btrfsitem.BlockGroup:
-					fmt.Fprintf(out, "\t\tblock group used %v chunk_objectid %v flags %v\n",
-						body.Used, body.ChunkObjectID, body.Flags)
-				case btrfsitem.FreeSpaceInfo:
-					fmt.Fprintf(out, "\t\tfree space info extent count %v flags %v\n",
-						body.ExtentCount, body.Flags)
-				case btrfsitem.FreeSpaceBitmap:
-					fmt.Fprintf(out, "\t\tfree space bitmap\n")
-				case btrfsitem.Chunk:
-					fmt.Fprintf(out, "\t\tlength %d owner %d stripe_len %v type %v\n",
-						body.Head.Size, body.Head.Owner, body.Head.StripeLen, body.Head.Type)
-					fmt.Fprintf(out, "\t\tio_align %v io_width %v sector_size %v\n",
-						body.Head.IOOptimalAlign, body.Head.IOOptimalWidth, body.Head.IOMinSize)
-					fmt.Fprintf(out, "\t\tnum_stripes %v sub_stripes %v\n",
-						body.Head.NumStripes, body.Head.SubStripes)
-					for i, stripe := range body.Stripes {
-						fmt.Fprintf(out, "\t\t\tstripe %v devid %d offset %d\n",
-							i, stripe.DeviceID, stripe.Offset)
-						fmt.Fprintf(out, "\t\t\tdev_uuid %v\n",
-							stripe.DeviceUUID)
-					}
-				case btrfsitem.Dev:
-					fmt.Fprintf(out, ""+
-						"\t\tdevid %d total_bytes %v bytes_used %v\n"+
-						"\t\tio_align %v io_width %v sector_size %v type %v\n"+
-						"\t\tgeneration %v start_offset %v dev_group %v\n"+
-						"\t\tseek_speed %v bandwidth %v\n"+
-						"\t\tuuid %v\n"+
-						"\t\tfsid %v\n",
-						body.DevID, body.NumBytes, body.NumBytesUsed,
-						body.IOOptimalAlign, body.IOOptimalWidth, body.IOMinSize, body.Type,
-						body.Generation, body.StartOffset, body.DevGroup,
-						body.SeekSpeed, body.Bandwidth,
-						body.DevUUID,
-						body.FSUUID)
-				case btrfsitem.DevExtent:
-					fmt.Fprintf(out, ""+
-						"\t\tdev extent chunk_tree %v\n"+
-						"\t\tchunk_objectid %v chunk_offset %d length %d\n"+
-						"\t\tchunk_tree_uuid %v\n",
-						body.ChunkTree, body.ChunkObjectID, body.ChunkOffset, body.Length,
-						body.ChunkTreeUUID)
-				//case btrfsitem.QGROUP_STATUS_KEY:
-				//	// TODO
-				//case btrfsitem.QGROUP_INFO_KEY:
-				//	// TODO
-				//case btrfsitem.QGROUP_LIMIT_KEY:
-				//	// TODO
-				case btrfsitem.UUIDMap:
-					fmt.Fprintf(out, "\t\tsubvol_id %d\n", body.ObjID)
-				//case btrfsitem.STRING_ITEM_KEY:
-				//	// TODO
-				case btrfsitem.DevStats:
-					fmt.Fprintf(out, "\t\tpersistent item objectid %v offset %v\n",
-						item.Key.ObjectID.Format(item.Key.ItemType), item.Key.Offset)
-					switch item.Key.ObjectID {
-					case btrfs.DEV_STATS_OBJECTID:
-						fmt.Fprintf(out, "\t\tdevice stats\n")
-						fmt.Fprintf(out, "\t\twrite_errs %v read_errs %v flush_errs %v corruption_errs %v generation %v\n",
-							body.Values[btrfsitem.DEV_STAT_WRITE_ERRS],
-							body.Values[btrfsitem.DEV_STAT_READ_ERRS],
-							body.Values[btrfsitem.DEV_STAT_FLUSH_ERRS],
-							body.Values[btrfsitem.DEV_STAT_CORRUPTION_ERRS],
-							body.Values[btrfsitem.DEV_STAT_GENERATION_ERRS])
-					default:
-						fmt.Fprintf(out, "\t\tunknown persistent item objectid %v\n", item.Key.ObjectID)
-					}
-				//case btrfsitem.TEMPORARY_ITEM_KEY:
-				//	// TODO
-				case btrfsitem.Empty:
-					switch item.Key.ItemType {
-					case btrfsitem.ORPHAN_ITEM_KEY: // 48
-						fmt.Fprintf(out, "\t\torphan item\n")
-					case btrfsitem.TREE_BLOCK_REF_KEY: // 176
-						fmt.Fprintf(out, "\t\ttree block backref\n")
-					case btrfsitem.SHARED_BLOCK_REF_KEY: // 182
-						fmt.Fprintf(out, "\t\tshared block backref\n")
-					case btrfsitem.FREE_SPACE_EXTENT_KEY: // 199
-						fmt.Fprintf(out, "\t\tfree space extent\n")
-					case btrfsitem.QGROUP_RELATION_KEY: // 246
-						// do nothing
-					//case btrfsitem.EXTENT_REF_V0_KEY:
-					//	fmt.Fprintf(out, "\t\textent ref v0 (deprecated)\n")
-					//case btrfsitem.CSUM_ITEM_KEY:
-					//	fmt.Fprintf(out, "\t\tcsum item\n")
-					default:
-						fmt.Fprintf(out, "\t\t(error) unhandled empty item type: %v\n", item.Key.ItemType)
-					}
-				case btrfsitem.Error:
-					fmt.Fprintf(out, "\t\t(error) error item: %v\n", body.Err)
+					fmt.Fprintf(out, "[%d] 0x%s", pos, sum.Fmt(sb.Data.ChecksumType))
+					pos = pos.Add(sectorSize)
+				}
+				fmt.Fprintf(out, "\n")
+			case btrfsitem.FileExtent:
+				fmt.Fprintf(out, "\t\tgeneration %v type %v\n",
+					body.Generation, body.Type)
+				switch body.Type {
+				case btrfsitem.FILE_EXTENT_INLINE:
+					fmt.Fprintf(out, "\t\tinline extent data size %v ram_bytes %v compression %v\n",
+						len(body.BodyInline), body.RAMBytes, body.Compression)
+				case btrfsitem.FILE_EXTENT_PREALLOC:
+					fmt.Fprintf(out, "\t\tprealloc data disk byte %v nr %v\n",
+						body.BodyExtent.DiskByteNr,
+						body.BodyExtent.DiskNumBytes)
+					fmt.Fprintf(out, "\t\tprealloc data offset %v nr %v\n",
+						body.BodyExtent.Offset,
+						body.BodyExtent.NumBytes)
+				case btrfsitem.FILE_EXTENT_REG:
+					fmt.Fprintf(out, "\t\textent data disk byte %d nr %d\n",
+						body.BodyExtent.DiskByteNr,
+						body.BodyExtent.DiskNumBytes)
+					fmt.Fprintf(out, "\t\textent data offset %d nr %d ram %v\n",
+						body.BodyExtent.Offset,
+						body.BodyExtent.NumBytes,
+						body.RAMBytes)
+					fmt.Fprintf(out, "\t\textent compression %v\n",
+						body.Compression)
 				default:
-					fmt.Fprintf(out, "\t\t(error) unhandled item type: %T\n", body)
+					fmt.Fprintf(out, "\t\t(error) unknown file extent type %v", body.Type)
 				}
-				return nil
-			},
+			case btrfsitem.BlockGroup:
+				fmt.Fprintf(out, "\t\tblock group used %v chunk_objectid %v flags %v\n",
+					body.Used, body.ChunkObjectID, body.Flags)
+			case btrfsitem.FreeSpaceInfo:
+				fmt.Fprintf(out, "\t\tfree space info extent count %v flags %v\n",
+					body.ExtentCount, body.Flags)
+			case btrfsitem.FreeSpaceBitmap:
+				fmt.Fprintf(out, "\t\tfree space bitmap\n")
+			case btrfsitem.Chunk:
+				fmt.Fprintf(out, "\t\tlength %d owner %d stripe_len %v type %v\n",
+					body.Head.Size, body.Head.Owner, body.Head.StripeLen, body.Head.Type)
+				fmt.Fprintf(out, "\t\tio_align %v io_width %v sector_size %v\n",
+					body.Head.IOOptimalAlign, body.Head.IOOptimalWidth, body.Head.IOMinSize)
+				fmt.Fprintf(out, "\t\tnum_stripes %v sub_stripes %v\n",
+					body.Head.NumStripes, body.Head.SubStripes)
+				for i, stripe := range body.Stripes {
+					fmt.Fprintf(out, "\t\t\tstripe %v devid %d offset %d\n",
+						i, stripe.DeviceID, stripe.Offset)
+					fmt.Fprintf(out, "\t\t\tdev_uuid %v\n",
+						stripe.DeviceUUID)
+				}
+			case btrfsitem.Dev:
+				fmt.Fprintf(out, ""+
+					"\t\tdevid %d total_bytes %v bytes_used %v\n"+
+					"\t\tio_align %v io_width %v sector_size %v type %v\n"+
+					"\t\tgeneration %v start_offset %v dev_group %v\n"+
+					"\t\tseek_speed %v bandwidth %v\n"+
+					"\t\tuuid %v\n"+
+					"\t\tfsid %v\n",
+					body.DevID, body.NumBytes, body.NumBytesUsed,
+					body.IOOptimalAlign, body.IOOptimalWidth, body.IOMinSize, body.Type,
+					body.Generation, body.StartOffset, body.DevGroup,
+					body.SeekSpeed, body.Bandwidth,
+					body.DevUUID,
+					body.FSUUID)
+			case btrfsitem.DevExtent:
+				fmt.Fprintf(out, ""+
+					"\t\tdev extent chunk_tree %v\n"+
+					"\t\tchunk_objectid %v chunk_offset %d length %d\n"+
+					"\t\tchunk_tree_uuid %v\n",
+					body.ChunkTree, body.ChunkObjectID, body.ChunkOffset, body.Length,
+					body.ChunkTreeUUID)
+			//case btrfsitem.QGROUP_STATUS_KEY:
+			//	// TODO
+			//case btrfsitem.QGROUP_INFO_KEY:
+			//	// TODO
+			//case btrfsitem.QGROUP_LIMIT_KEY:
+			//	// TODO
+			case btrfsitem.UUIDMap:
+				fmt.Fprintf(out, "\t\tsubvol_id %d\n", body.ObjID)
+			//case btrfsitem.STRING_ITEM_KEY:
+			//	// TODO
+			case btrfsitem.DevStats:
+				fmt.Fprintf(out, "\t\tpersistent item objectid %v offset %v\n",
+					item.Key.ObjectID.Format(item.Key.ItemType), item.Key.Offset)
+				switch item.Key.ObjectID {
+				case btrfs.DEV_STATS_OBJECTID:
+					fmt.Fprintf(out, "\t\tdevice stats\n")
+					fmt.Fprintf(out, "\t\twrite_errs %v read_errs %v flush_errs %v corruption_errs %v generation %v\n",
+						body.Values[btrfsitem.DEV_STAT_WRITE_ERRS],
+						body.Values[btrfsitem.DEV_STAT_READ_ERRS],
+						body.Values[btrfsitem.DEV_STAT_FLUSH_ERRS],
+						body.Values[btrfsitem.DEV_STAT_CORRUPTION_ERRS],
+						body.Values[btrfsitem.DEV_STAT_GENERATION_ERRS])
+				default:
+					fmt.Fprintf(out, "\t\tunknown persistent item objectid %v\n", item.Key.ObjectID)
+				}
+			//case btrfsitem.TEMPORARY_ITEM_KEY:
+			//	// TODO
+			case btrfsitem.Empty:
+				switch item.Key.ItemType {
+				case btrfsitem.ORPHAN_ITEM_KEY: // 48
+					fmt.Fprintf(out, "\t\torphan item\n")
+				case btrfsitem.TREE_BLOCK_REF_KEY: // 176
+					fmt.Fprintf(out, "\t\ttree block backref\n")
+				case btrfsitem.SHARED_BLOCK_REF_KEY: // 182
+					fmt.Fprintf(out, "\t\tshared block backref\n")
+				case btrfsitem.FREE_SPACE_EXTENT_KEY: // 199
+					fmt.Fprintf(out, "\t\tfree space extent\n")
+				case btrfsitem.QGROUP_RELATION_KEY: // 246
+					// do nothing
+				//case btrfsitem.EXTENT_REF_V0_KEY:
+				//	fmt.Fprintf(out, "\t\textent ref v0 (deprecated)\n")
+				//case btrfsitem.CSUM_ITEM_KEY:
+				//	fmt.Fprintf(out, "\t\tcsum item\n")
+				default:
+					fmt.Fprintf(out, "\t\t(error) unhandled empty item type: %v\n", item.Key.ItemType)
+				}
+			case btrfsitem.Error:
+				fmt.Fprintf(out, "\t\t(error) error item: %v\n", body.Err)
+			default:
+				fmt.Fprintf(out, "\t\t(error) unhandled item type: %T\n", body)
+			}
+			return nil
+		},
+	}
+	handlers.BadItem = handlers.Item
+	fs.TreeWalk(
+		treeID,
+		func(err *btrfs.TreeError) {
+			dlog.Error(ctx, err)
 		},
+		handlers,
 	)
 }