write btrfs-clear-bad-nodes

1 files changed, 94 insertions, 0 deletions

diff --git a/cmd/btrfs-clear-bad-nodes/main.go b/cmd/btrfs-clear-bad-nodes/main.go
new file mode 100644
index 0000000..754e08b
--- /dev/null
+++ b/cmd/btrfs-clear-bad-nodes/main.go
@@ -0,0 +1,94 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"lukeshu.com/btrfs-tools/pkg/btrfs"
+	"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsvol"
+	"lukeshu.com/btrfs-tools/pkg/btrfsmisc"
+	"lukeshu.com/btrfs-tools/pkg/util"
+)
+
+func main() {
+	if err := Main(os.Args[1:]...); err != nil {
+		fmt.Fprintf(os.Stderr, "%v: error: %v\n", os.Args[0], err)
+		os.Exit(1)
+	}
+}
+
+func Main(imgfilenames ...string) (err error) {
+	maybeSetErr := func(_err error) {
+		if _err != nil && err == nil {
+			err = _err
+		}
+	}
+
+	fs, err := btrfsmisc.Open(os.O_RDWR, imgfilenames...)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		maybeSetErr(fs.Close())
+	}()
+
+	var treeName string
+	btrfsmisc.WalkFS(fs, btrfsmisc.WalkFSHandler{
+		PreTree: func(name string, _ btrfsvol.LogicalAddr) {
+			treeName = name
+		},
+		Err: func(err error) {
+			fmt.Printf("error: %v\n", err)
+		},
+		UnsafeNodes: true,
+		TreeWalkHandler: btrfs.TreeWalkHandler{
+			Node: func(path btrfs.TreePath, node *util.Ref[btrfsvol.LogicalAddr, btrfs.Node], err error) error {
+				if node == nil || err == nil {
+					return nil
+				}
+				origErr := err
+				if len(path) < 2 {
+					// TODO(lukeshu): Get info from the superblock and such
+					// instead of the parent node, so that we can repair broken
+					// root nodes.
+					return fmt.Errorf("root node: %w", err)
+				}
+				parentNode, err := fs.ReadNode(path[len(path)-2].NodeAddr)
+				if err != nil {
+					return err
+				}
+				node.Data = btrfs.Node{
+					Size:         node.Data.Size,
+					ChecksumType: node.Data.ChecksumType,
+					Head: btrfs.NodeHeader{
+						//Checksum:   filled below,
+						MetadataUUID: parentNode.Data.Head.MetadataUUID,
+						Addr:         node.Addr,
+						Flags:        btrfs.NodeWritten,
+						BackrefRev:   parentNode.Data.Head.BackrefRev,
+						Generation:   0,
+						Owner:        parentNode.Data.Head.Owner,
+						NumItems:     0,
+						Level:        parentNode.Data.Head.Level - 1,
+					},
+				}
+				node.Data.Head.Checksum, err = node.Data.CalculateChecksum()
+				if err != nil {
+					return btrfsmisc.WalkErr{
+						TreeName: treeName,
+						Path:     path,
+						Err:      err,
+					}
+				}
+				if err := node.Write(); err != nil {
+					return err
+				}
+
+				fmt.Printf("fixed node@%v (err was %v)\n", node.Addr, origErr)
+				return nil
+			},
+		},
+	})
+
+	return nil
+}