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package btrfsmisc
import (
"fmt"
"lukeshu.com/btrfs-tools/pkg/btrfs"
"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsitem"
"lukeshu.com/btrfs-tools/pkg/util"
)
type WalkErr struct {
TreeName string
Path btrfs.WalkTreePath
Err error
}
func (e WalkErr) Unwrap() error { return e.Err }
func (e WalkErr) Error() string {
if len(e.Path) == 0 {
return fmt.Sprintf("%v: %v", e.TreeName, e.Err)
}
return fmt.Sprintf("%v: %v: %v", e.TreeName, e.Path, e.Err)
}
type WalkFSHandler struct {
Err func(error)
// Callbacks for entire trees
PreTree func(name string, laddr btrfs.LogicalAddr)
PostTree func(name string, laddr btrfs.LogicalAddr)
// Callbacks for nodes or smaller
btrfs.WalkTreeHandler
}
// WalkFS walks all trees in a *btrfs.FS. Rather than returning an
// error, it calls errCb each time an error is encountered. The error
// will always be of type WalkErr.
func WalkFS(fs *btrfs.FS, cbs WalkFSHandler) {
var treeName string
handleErr := func(path btrfs.WalkTreePath, err error) {
cbs.Err(WalkErr{
TreeName: treeName,
Path: path,
Err: err,
})
}
var foundTrees []struct {
Name string
Root btrfs.LogicalAddr
}
origItem := cbs.Item
cbs.Item = func(path btrfs.WalkTreePath, item btrfs.Item) error {
if item.Head.Key.ItemType == btrfsitem.ROOT_ITEM_KEY {
root, ok := item.Body.(btrfsitem.Root)
if !ok {
handleErr(path, fmt.Errorf("ROOT_ITEM_KEY is a %T, not a btrfsitem.Root", item.Body))
} else {
foundTrees = append(foundTrees, struct {
Name string
Root btrfs.LogicalAddr
}{
Name: fmt.Sprintf("tree %v (via %v %v)",
item.Head.Key.ObjectID.Format(0), treeName, path),
Root: root.ByteNr,
})
}
}
if origItem != nil {
return origItem(path, item)
}
return nil
}
origNode := cbs.Node
cbs.Node = func(path btrfs.WalkTreePath, node *util.Ref[btrfs.LogicalAddr, btrfs.Node], err error) error {
if err != nil {
handleErr(path, err)
}
if node != nil && origNode != nil {
return origNode(path, node, nil)
}
return nil
}
treeName = "superblock"
superblock, err := fs.Superblock()
if err != nil {
handleErr(nil, err)
return
}
treeName = "root tree"
cbs.PreTree(treeName, superblock.Data.RootTree)
if err := fs.WalkTree(superblock.Data.RootTree, cbs.WalkTreeHandler); err != nil {
handleErr(nil, err)
}
cbs.PostTree(treeName, superblock.Data.RootTree)
treeName = "chunk tree"
cbs.PreTree(treeName, superblock.Data.ChunkTree)
if err := fs.WalkTree(superblock.Data.ChunkTree, cbs.WalkTreeHandler); err != nil {
handleErr(nil, err)
}
cbs.PostTree(treeName, superblock.Data.ChunkTree)
treeName = "log tree"
cbs.PreTree(treeName, superblock.Data.LogTree)
if err := fs.WalkTree(superblock.Data.LogTree, cbs.WalkTreeHandler); err != nil {
handleErr(nil, err)
}
cbs.PostTree(treeName, superblock.Data.LogTree)
treeName = "block group tree"
cbs.PreTree(treeName, superblock.Data.BlockGroupRoot)
if err := fs.WalkTree(superblock.Data.BlockGroupRoot, cbs.WalkTreeHandler); err != nil {
handleErr(nil, err)
}
cbs.PostTree(treeName, superblock.Data.BlockGroupRoot)
for _, tree := range foundTrees {
treeName = tree.Name
cbs.PreTree(treeName, tree.Root)
if err := fs.WalkTree(tree.Root, cbs.WalkTreeHandler); err != nil {
handleErr(nil, err)
}
cbs.PostTree(treeName, tree.Root)
}
}
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