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package main
import (
"fmt"
"os"
"sort"
"lukeshu.com/btrfs-tools/pkg/btrfs"
"lukeshu.com/btrfs-tools/pkg/btrfs/btrfsitem"
"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, "%s: error: %v\n", os.Args[0], err)
os.Exit(1)
}
}
func Main(imgfilename string) (err error) {
maybeSetErr := func(_err error) {
if _err != nil && err == nil {
err = _err
}
}
fh, err := os.Open(imgfilename)
if err != nil {
return err
}
defer func() {
maybeSetErr(fh.Close())
}()
fs := &btrfs.FS{
Devices: []*btrfs.Device{
{
File: fh,
},
},
}
fmt.Printf("\nPass 0: superblocks...\n") ///////////////////////////////////////////////////
superblock, err := fs.Superblock()
if err != nil {
return fmt.Errorf("superblock: %w", err)
}
fmt.Printf("\nPass 1: chunk mappings...\n") ////////////////////////////////////////////////
fmt.Printf("Pass 1: ... initializing chunk mappings\n")
if err := fs.Init(); err != nil {
fmt.Printf("Pass 1: ... init chunk tree: error: %v\n", err)
}
fmt.Printf("Pass 1: ... walking chunk tree\n")
visitedChunkNodes := make(map[btrfs.LogicalAddr]struct{})
if err := fs.WalkTree(superblock.Data.ChunkTree, btrfs.WalkTreeHandler{
MidNode: func(node *util.Ref[btrfs.LogicalAddr, btrfs.Node]) error {
visitedChunkNodes[node.Addr] = struct{}{}
return nil
},
}); err != nil {
fmt.Printf("Pass 1: ... walk chunk tree: error: %v\n", err)
}
fmt.Printf("Pass 1: ... scanning for nodes\n")
foundNodes := make(map[btrfs.LogicalAddr][]btrfs.PhysicalAddr)
var lostAndFoundChunks []btrfs.SysChunk
if err := btrfsmisc.ScanForNodes(fs.Devices[0], superblock.Data, func(nodeRef *util.Ref[btrfs.PhysicalAddr, btrfs.Node], err error) {
if err != nil {
fmt.Println(err)
return
}
foundNodes[nodeRef.Data.Head.Addr] = append(foundNodes[nodeRef.Data.Head.Addr], nodeRef.Addr)
_, alreadyVisited := visitedChunkNodes[nodeRef.Data.Head.Addr]
if nodeRef.Data.Head.Owner == btrfs.CHUNK_TREE_OBJECTID && !alreadyVisited {
for i, item := range nodeRef.Data.BodyLeaf {
if item.Head.Key.ItemType != btrfsitem.CHUNK_ITEM_KEY {
continue
}
chunk, ok := item.Body.(btrfsitem.Chunk)
if !ok {
fmt.Printf("Pass 1: node@%d: item %d: error: type is CHUNK_ITEM_KEY, but struct is %T\n",
nodeRef.Addr, i, item.Body)
continue
}
fmt.Printf("Pass 1: node@%d: item %d: found chunk\n",
nodeRef.Addr, i)
lostAndFoundChunks = append(lostAndFoundChunks, btrfs.SysChunk{
Key: item.Head.Key,
Chunk: chunk,
})
}
}
}); err != nil {
return err
}
fmt.Printf("Pass 1: ... re-inserting lost+found chunks\n")
if len(lostAndFoundChunks) > 0 {
panic("TODO")
}
fmt.Printf("Pass 1: ... re-constructing stripes for lost+found nodes\n")
lostAndFoundNodes := make(map[btrfs.PhysicalAddr]btrfs.LogicalAddr)
for laddr, readPaddrs := range foundNodes {
resolvedPaddrs, _ := fs.Resolve(laddr)
for _, readPaddr := range readPaddrs {
if _, ok := resolvedPaddrs[btrfs.QualifiedPhysicalAddr{
Dev: superblock.Data.DevItem.DevUUID,
Addr: readPaddr,
}]; !ok {
lostAndFoundNodes[readPaddr] = laddr
}
}
}
sortedPaddrs := make([]btrfs.PhysicalAddr, 0, len(lostAndFoundNodes))
for paddr := range lostAndFoundNodes {
sortedPaddrs = append(sortedPaddrs, paddr)
}
sort.Slice(sortedPaddrs, func(i, j int) bool {
return sortedPaddrs[i] < sortedPaddrs[j]
})
type stripe struct {
PAddr btrfs.PhysicalAddr
LAddr btrfs.LogicalAddr
Size uint64
}
var stripes []stripe
for _, paddr := range sortedPaddrs {
var lastStripe *stripe
if len(stripes) > 0 {
lastStripe = &stripes[len(stripes)-1]
}
if lastStripe != nil && (lastStripe.PAddr+btrfs.PhysicalAddr(lastStripe.Size)) == paddr {
lastStripe.Size += uint64(superblock.Data.NodeSize)
} else {
stripes = append(stripes, stripe{
PAddr: paddr,
LAddr: lostAndFoundNodes[paddr],
Size: uint64(superblock.Data.NodeSize),
})
}
}
fmt.Printf("Pass 1: ... reconstructed stripes: %#v\n", stripes)
fmt.Printf("\nPass 2: ?????????????????????????\n") ////////////////////////////////////////
/*
fmt.Printf("node@%d: physical_addr=0x%0X logical_addr=0x%0X generation=%d owner=%v level=%d\n",
nodeRef.Addr,
nodeRef.Addr, nodeRef.Data.Head.Addr,
nodeRef.Data.Head.Generation, nodeRef.Data.Head.Owner, nodeRef.Data.Head.Level)
srcPaddr := btrfs.QualifiedPhysicalAddr{
Dev: superblock.Data.DevItem.DevUUID,
Addr: nodeRef.Addr,
}
resPaddrs, _ := fs.Resolve(nodeRef.Data.Head.Addr)
if len(resPaddrs) == 0 {
fmt.Printf("node@%d: logical_addr=0x%0X is not mapped\n",
nodeRef.Addr, nodeRef.Data.Head.Addr)
} else if _, ok := resPaddrs[srcPaddr]; !ok {
fmt.Printf("node@%d: logical_addr=0x%0X maps to %v, not %v\n",
nodeRef.Addr, nodeRef.Data.Head.Addr, resPaddrs, srcPaddr)
}
*/
return nil
}
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