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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package main
import (
"context"
"fmt"
"os"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsinspect"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsutil"
"git.lukeshu.com/btrfs-progs-ng/lib/diskio"
)
func pass1(ctx context.Context, fs *btrfs.FS, superblock *btrfs.Superblock) (map[btrfsvol.LogicalAddr]struct{}, error) {
fmt.Printf("\nPass 1: chunk mappings...\n")
fmt.Printf("Pass 1: ... walking fs\n")
visitedNodes := make(map[btrfsvol.LogicalAddr]struct{})
btrfsutil.WalkAllTrees(ctx, fs, btrfsutil.WalkAllTreesHandler{
TreeWalkHandler: btrfs.TreeWalkHandler{
Node: func(path btrfs.TreePath, node *diskio.Ref[btrfsvol.LogicalAddr, btrfs.Node]) error {
visitedNodes[node.Addr] = struct{}{}
return nil
},
},
Err: func(err *btrfsutil.WalkError) {
fmt.Printf("Pass 1: ... walk fs: error: %v\n", err)
},
})
fsFoundNodes := make(map[btrfsvol.LogicalAddr]struct{})
for _, dev := range fs.LV.PhysicalVolumes() {
fmt.Printf("Pass 1: ... dev[%q] scanning for nodes...\n", dev.Name())
devResult, err := btrfsinspect.ScanOneDevice(ctx, dev, *superblock)
if err != nil {
return nil, err
}
fmt.Printf("Pass 1: ... dev[%q] re-inserting lost+found mappings\n", dev.Name())
devResult.AddToLV(ctx, fs, dev)
// merge those results in to the total-fs results
for laddr := range devResult.FoundNodes {
fsFoundNodes[laddr] = struct{}{}
}
}
fmt.Printf("Pass 1: ... logical address space:\n")
btrfsinspect.PrintLogicalSpace(os.Stdout, fs)
fmt.Printf("Pass 1: ... physical address space:\n")
btrfsinspect.PrintPhysicalSpace(os.Stdout, fs)
fmt.Printf("Pass 1: ... writing re-constructed chunks\n")
pass1WriteReconstructedChunks(ctx, fs)
return fsFoundNodes, nil
}
func pass1WriteReconstructedChunks(ctx context.Context, fs *btrfs.FS) {
superblock, _ := fs.Superblock()
// FIXME(lukeshu): OK, so this just assumes that all the
// reconstructed stripes fit in one node, and that we can just
// store that node at the root node of the chunk tree. This
// isn't true in general, but it's true of my particular
// filesystem.
reconstructedNode := &diskio.Ref[btrfsvol.LogicalAddr, btrfs.Node]{
File: fs,
Addr: superblock.ChunkTree,
Data: btrfs.Node{
Size: superblock.NodeSize,
Head: btrfs.NodeHeader{
MetadataUUID: superblock.EffectiveMetadataUUID(),
Addr: superblock.ChunkTree,
Flags: btrfs.NodeWritten,
//BackrefRef: ???,
//ChunkTreeUUID: ???,
Generation: superblock.ChunkRootGeneration,
Owner: btrfs.CHUNK_TREE_OBJECTID,
Level: 0,
},
},
}
for _, dev := range fs.LV.PhysicalVolumes() {
superblock, _ := dev.Superblock()
reconstructedNode.Data.BodyLeaf = append(reconstructedNode.Data.BodyLeaf, btrfs.Item{
Key: btrfs.Key{
ObjectID: btrfs.DEV_ITEMS_OBJECTID,
ItemType: btrfsitem.DEV_ITEM_KEY,
Offset: uint64(superblock.DevItem.DevID),
},
Body: superblock.DevItem,
})
}
for _, mapping := range fs.LV.Mappings() {
chunkIdx := len(reconstructedNode.Data.BodyLeaf) - 1
if len(reconstructedNode.Data.BodyLeaf) == 0 || reconstructedNode.Data.BodyLeaf[chunkIdx].Key.Offset != uint64(mapping.LAddr) {
reconstructedNode.Data.BodyLeaf = append(reconstructedNode.Data.BodyLeaf, btrfs.Item{
Key: btrfs.Key{
ObjectID: btrfs.FIRST_CHUNK_TREE_OBJECTID,
ItemType: btrfsitem.CHUNK_ITEM_KEY,
Offset: uint64(mapping.LAddr),
},
Body: btrfsitem.Chunk{
Head: btrfsitem.ChunkHeader{
Size: mapping.Size,
Owner: btrfs.EXTENT_TREE_OBJECTID,
StripeLen: 65536, // ???
Type: mapping.Flags.Val,
IOOptimalAlign: superblock.DevItem.IOOptimalAlign,
IOOptimalWidth: superblock.DevItem.IOOptimalWidth,
IOMinSize: superblock.DevItem.IOMinSize,
SubStripes: 1,
},
},
})
chunkIdx++
}
dev := fs.LV.PhysicalVolumes()[mapping.PAddr.Dev]
devSB, _ := dev.Superblock()
chunkBody := reconstructedNode.Data.BodyLeaf[chunkIdx].Body.(btrfsitem.Chunk)
chunkBody.Stripes = append(chunkBody.Stripes, btrfsitem.ChunkStripe{
DeviceID: mapping.PAddr.Dev,
Offset: mapping.PAddr.Addr,
DeviceUUID: devSB.DevItem.DevUUID,
})
reconstructedNode.Data.BodyLeaf[chunkIdx].Body = chunkBody
}
var err error
reconstructedNode.Data.Head.Checksum, err = reconstructedNode.Data.CalculateChecksum()
if err != nil {
fmt.Printf("Pass 1: ... new node checksum: error: %v\n", err)
}
if err := reconstructedNode.Write(); err != nil {
fmt.Printf("Pass 1: ... write new node: error: %v\n", err)
}
if err := fs.ReInit(ctx); err != nil {
fmt.Printf("Pass 1: ... re-init mappings: %v\n", err)
}
sbs, _ := fs.Superblocks()
for i, sb := range sbs {
sb.Data.ChunkLevel = reconstructedNode.Data.Head.Level
sb.Data.Checksum, err = sb.Data.CalculateChecksum()
if err != nil {
fmt.Printf("Pass 1: ... calculate superblock %d checksum: %v\n", i, err)
}
if err := sb.Write(); err != nil {
fmt.Printf("Pass 1: ... write superblock %d: %v\n", i, err)
}
}
}
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