From 0057ac685125aea5cf06dfd8eeaa7c7d52e64dfa Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Fri, 15 Jul 2022 14:36:47 -0600
Subject: wip
---
lib/btrfsprogs/btrfsinspect/scanforextents/csum.go | 125 ++++++++++++
lib/btrfsprogs/btrfsinspect/scanforextents/gaps.go | 82 ++++++++
.../btrfsinspect/scanforextents/scanforextents.go | 214 +++++++++++++++++++++
.../btrfsinspect/scanforextents/scanfornodes.go | 101 ++++++++++
4 files changed, 522 insertions(+)
create mode 100644 lib/btrfsprogs/btrfsinspect/scanforextents/csum.go
create mode 100644 lib/btrfsprogs/btrfsinspect/scanforextents/gaps.go
create mode 100644 lib/btrfsprogs/btrfsinspect/scanforextents/scanforextents.go
create mode 100644 lib/btrfsprogs/btrfsinspect/scanforextents/scanfornodes.go
(limited to 'lib/btrfsprogs/btrfsinspect/scanforextents')
diff --git a/lib/btrfsprogs/btrfsinspect/scanforextents/csum.go b/lib/btrfsprogs/btrfsinspect/scanforextents/csum.go
new file mode 100644
index 0000000..7944497
--- /dev/null
+++ b/lib/btrfsprogs/btrfsinspect/scanforextents/csum.go
@@ -0,0 +1,125 @@
+// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package scanforextents
+
+import (
+ "context"
+ "errors"
+ "fmt"
+
+ "github.com/datawire/dlib/dlog"
+
+ "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/btrfssum"
+ "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
+)
+
+const csumBlockSize = 4 * 1024
+
+func ChecksumLogical(fs btrfs.Trees, alg btrfssum.CSumType, laddr btrfsvol.LogicalAddr) (btrfssum.CSum, error) {
+ var dat [csumBlockSize]byte
+ if _, err := fs.ReadAt(dat[:], laddr); err != nil {
+ return btrfssum.CSum{}, err
+ }
+ return alg.Sum(dat[:])
+}
+
+func ChecksumPhysical(dev *btrfs.Device, alg btrfssum.CSumType, paddr btrfsvol.PhysicalAddr) (btrfssum.CSum, error) {
+ var dat [csumBlockSize]byte
+ if _, err := dev.ReadAt(dat[:], paddr); err != nil {
+ return btrfssum.CSum{}, err
+ }
+ return alg.Sum(dat[:])
+}
+
+func ChecksumQualifiedPhysical(fs *btrfs.FS, alg btrfssum.CSumType, paddr btrfsvol.QualifiedPhysicalAddr) (btrfssum.CSum, error) {
+ dev := fs.LV.PhysicalVolumes()[paddr.Dev]
+ if dev == nil {
+ return btrfssum.CSum{}, fmt.Errorf("no such device_id=%v", paddr.Dev)
+ }
+ return ChecksumPhysical(dev, alg, paddr.Addr)
+}
+
+type shortSum string
+
+func readCSumTree(ctx context.Context, fs btrfs.Trees) map[shortSum][]btrfsvol.LogicalAddr {
+ sb, _ := fs.Superblock()
+
+ sum2laddrs := make(map[shortSum][]btrfsvol.LogicalAddr)
+ var cntUnmapped, cntErr, cntMismatch, cntValid int
+ fs.TreeWalk(ctx, btrfs.CSUM_TREE_OBJECTID,
+ func(err *btrfs.TreeError) {
+ dlog.Error(ctx, err)
+ },
+ btrfs.TreeWalkHandler{
+ Item: func(path btrfs.TreePath, item btrfs.Item) error {
+ if item.Key.ItemType != btrfsitem.EXTENT_CSUM_KEY {
+ return nil
+ }
+ body := item.Body.(btrfsitem.ExtentCSum)
+
+ for i, treeSum := range body.Sums {
+ laddr := btrfsvol.LogicalAddr(item.Key.Offset) + (btrfsvol.LogicalAddr(i) * csumBlockSize)
+ readSum, err := ChecksumLogical(fs, sb.ChecksumType, laddr)
+ if err != nil {
+ if errors.Is(err, btrfsvol.ErrCouldNotMap) {
+ cntUnmapped++
+ treeShortSum := shortSum(treeSum[:body.ChecksumSize])
+ sum2laddrs[treeShortSum] = append(sum2laddrs[treeShortSum], laddr)
+ continue
+ }
+ dlog.Error(ctx, err)
+ cntErr++
+ continue
+ }
+ if readSum != treeSum {
+ dlog.Errorf(ctx, "checksum mismatch at laddr=%v: CSUM_TREE=%v != read=%v",
+ laddr, treeSum, readSum)
+ cntMismatch++
+ continue
+ }
+ cntValid++
+ }
+ return nil
+ },
+ },
+ )
+
+ total := cntErr + cntUnmapped + cntMismatch + cntValid
+ dlog.Infof(ctx, " checksum errors : %v", cntErr)
+ dlog.Infof(ctx, " unmapped checksums : %v", cntUnmapped)
+ dlog.Infof(ctx, " mismatched checksums : %v", cntMismatch)
+ dlog.Infof(ctx, " valid checksums : %v", cntValid)
+ dlog.Infof(ctx, " -------------------------:")
+ dlog.Infof(ctx, " total checksums : %v", total)
+ dlog.Infof(ctx, " distinct unmapped : %v", len(sum2laddrs))
+
+ return sum2laddrs
+}
+
+func LookupCSum(fs btrfs.Trees, alg btrfssum.CSumType, laddr btrfsvol.LogicalAddr) (btrfssum.CSum, error) {
+ item, err := fs.TreeSearch(btrfs.CSUM_TREE_OBJECTID, func(key btrfs.Key, size uint32) int {
+ itemBeg := btrfsvol.LogicalAddr(key.ObjectID)
+ numSums := int64(size) / int64(alg.Size())
+ itemEnd := itemBeg + btrfsvol.LogicalAddr(numSums*csumBlockSize)
+ switch {
+ case itemEnd <= laddr:
+ return 1
+ case laddr < itemBeg:
+ return -1
+ default:
+ return 0
+ }
+ })
+ if err != nil {
+ return btrfssum.CSum{}, err
+ }
+ body, ok := item.Body.(btrfsitem.ExtentCSum)
+ if !ok {
+ return btrfssum.CSum{}, fmt.Errorf("item body is %T not ExtentCSum", item.Body)
+ }
+ return body.Sums[int(laddr-btrfsvol.LogicalAddr(item.Key.ObjectID))/csumBlockSize], nil
+}
diff --git a/lib/btrfsprogs/btrfsinspect/scanforextents/gaps.go b/lib/btrfsprogs/btrfsinspect/scanforextents/gaps.go
new file mode 100644
index 0000000..90351a5
--- /dev/null
+++ b/lib/btrfsprogs/btrfsinspect/scanforextents/gaps.go
@@ -0,0 +1,82 @@
+// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package scanforextents
+
+import (
+ "context"
+ "sort"
+
+ "golang.org/x/exp/constraints"
+
+ "git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
+ "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
+)
+
+type PhysicalGap struct {
+ Beg, End btrfsvol.PhysicalAddr
+}
+
+func ListPhysicalGaps(fs *btrfs.FS) map[btrfsvol.DeviceID][]PhysicalGap {
+ gaps := make(map[btrfsvol.DeviceID][]PhysicalGap)
+ pos := make(map[btrfsvol.DeviceID]btrfsvol.PhysicalAddr)
+ mappings := fs.LV.Mappings()
+ sort.Slice(mappings, func(i, j int) bool {
+ return mappings[i].PAddr.Cmp(mappings[j].PAddr) < 0
+ })
+ for _, mapping := range mappings {
+ if pos[mapping.PAddr.Dev] < mapping.PAddr.Addr {
+ gaps[mapping.PAddr.Dev] = append(gaps[mapping.PAddr.Dev], PhysicalGap{
+ Beg: pos[mapping.PAddr.Dev],
+ End: mapping.PAddr.Addr,
+ })
+ }
+ if pos[mapping.PAddr.Dev] < mapping.PAddr.Addr.Add(mapping.Size) {
+ pos[mapping.PAddr.Dev] = mapping.PAddr.Addr.Add(mapping.Size)
+ }
+ }
+ for devID, dev := range fs.LV.PhysicalVolumes() {
+ devSize := dev.Size()
+ if pos[devID] < devSize {
+ gaps[devID] = append(gaps[devID], PhysicalGap{
+ Beg: pos[devID],
+ End: devSize,
+ })
+ }
+ }
+ return gaps
+}
+
+func roundUp[T constraints.Integer](x, multiple T) T {
+ return ((x + multiple - 1) / multiple) * multiple
+}
+
+func WalkGapsOneDev(ctx context.Context, dev *btrfs.Device,
+ gaps []PhysicalGap, blockSize btrfsvol.PhysicalAddr,
+ progress func(cur, total int64),
+ main func(btrfsvol.PhysicalAddr) error,
+) error {
+ var totalBlocks int64
+ for _, gap := range gaps {
+ for paddr := roundUp(gap.Beg, blockSize); paddr+blockSize <= gap.End; paddr += blockSize {
+ totalBlocks++
+ }
+ }
+
+ var curBlock int64
+ for _, gap := range gaps {
+ for paddr := roundUp(gap.Beg, blockSize); paddr+blockSize <= gap.End; paddr += blockSize {
+ if err := ctx.Err(); err != nil {
+ return err
+ }
+ progress(curBlock, totalBlocks)
+ curBlock++
+ if err := main(paddr); err != nil {
+ return err
+ }
+ }
+ }
+ progress(curBlock, totalBlocks)
+ return nil
+}
diff --git a/lib/btrfsprogs/btrfsinspect/scanforextents/scanforextents.go b/lib/btrfsprogs/btrfsinspect/scanforextents/scanforextents.go
new file mode 100644
index 0000000..1537fb5
--- /dev/null
+++ b/lib/btrfsprogs/btrfsinspect/scanforextents/scanforextents.go
@@ -0,0 +1,214 @@
+// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package scanforextents
+
+import (
+ "context"
+ "sync"
+
+ "github.com/datawire/dlib/dgroup"
+ "github.com/datawire/dlib/dlog"
+
+ "git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
+ "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfssum"
+ "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
+ "git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsutil"
+ "git.lukeshu.com/btrfs-progs-ng/lib/containers"
+)
+
+func ScanForExtents(ctx context.Context, fs *btrfs.FS, blockGroups *BlockGroupTree) error {
+ treeReader := btrfsutil.NewBrokenTrees(ctx, fs)
+
+ dlog.Info(ctx, "Reading checksum tree...")
+ sum2laddrs := readCSumTree(ctx, treeReader)
+ if len(sum2laddrs) == 0 {
+ dlog.Info(ctx, "No unmapped checksums")
+ return nil
+ }
+
+ devs := fs.LV.PhysicalVolumes()
+ gaps := ListPhysicalGaps(fs)
+
+ newMappings := &ExtentMappings{
+ InFS: treeReader,
+ InLV: &fs.LV,
+ InSum2laddrs: sum2laddrs,
+ InBlockGroups: blockGroups,
+ }
+
+ grp := dgroup.NewGroup(ctx, dgroup.GroupConfig{})
+ for devID := range gaps {
+ dev := devs[devID]
+ devGaps := gaps[devID]
+ grp.Go(dev.Name(), func(ctx context.Context) error {
+ return newMappings.ScanOneDev(ctx, dev, devGaps)
+ })
+ }
+ if err := grp.Wait(); err != nil {
+ return err
+ }
+
+ for laddr, mappings := range newMappings.OutSum2mappings {
+ if len(mappings) > 1 {
+ dlog.Errorf(ctx, "multiple possibilities for laddr=%v :", laddr)
+ for _, mapping := range mappings {
+ dlog.Errorf(ctx, " - %#v", *mapping)
+ }
+ continue
+ }
+ if err := fs.LV.AddMapping(*mappings[0]); err != nil {
+ dlog.Error(ctx, err)
+ }
+ }
+
+ return nil
+}
+
+type ExtentMappings struct {
+ // input
+ InFS btrfs.Trees
+ InLV *btrfsvol.LogicalVolume[*btrfs.Device]
+ InSum2laddrs map[shortSum][]btrfsvol.LogicalAddr
+ InBlockGroups *BlockGroupTree
+
+ // state
+ initOnce sync.Once
+ initErr error
+ alg btrfssum.CSumType
+ internedMappingsMu sync.Mutex
+ internedMappings map[btrfsvol.Mapping]*btrfsvol.Mapping
+
+ // output
+ sum2lock map[shortSum]*sync.Mutex
+ OutSum2mappings map[shortSum][]*btrfsvol.Mapping
+}
+
+func (em *ExtentMappings) init() error {
+ em.initOnce.Do(func() {
+ sb, err := em.InFS.Superblock()
+ if err != nil {
+ em.initErr = err
+ return
+ }
+ em.alg = sb.ChecksumType
+ em.internedMappings = make(map[btrfsvol.Mapping]*btrfsvol.Mapping)
+ em.sum2lock = make(map[shortSum]*sync.Mutex, len(em.InSum2laddrs))
+ for sum := range em.InSum2laddrs {
+ em.sum2lock[sum] = new(sync.Mutex)
+ }
+ em.OutSum2mappings = make(map[shortSum][]*btrfsvol.Mapping)
+ })
+ return em.initErr
+}
+
+func (em *ExtentMappings) considerMapping(dev *btrfs.Device, laddr btrfsvol.LogicalAddr, paddr btrfsvol.QualifiedPhysicalAddr) (btrfsvol.Mapping, bool) {
+ blockgroup := LookupBlockGroup(em.InBlockGroups, laddr, csumBlockSize)
+ if blockgroup == nil {
+ return btrfsvol.Mapping{
+ LAddr: laddr,
+ PAddr: paddr,
+ Size: csumBlockSize,
+ }, true
+ }
+ mapping := btrfsvol.Mapping{
+ LAddr: blockgroup.LAddr,
+ PAddr: btrfsvol.QualifiedPhysicalAddr{
+ Dev: paddr.Dev,
+ Addr: paddr.Addr.Add(laddr.Sub(blockgroup.LAddr)),
+ },
+ Size: blockgroup.Size,
+ SizeLocked: true,
+ Flags: containers.Optional[btrfsvol.BlockGroupFlags]{
+ OK: true,
+ Val: blockgroup.Flags,
+ },
+ }
+ if !em.InLV.CouldAddMapping(mapping) {
+ return btrfsvol.Mapping{}, false
+ }
+
+ for offset := btrfsvol.AddrDelta(0); offset <= mapping.Size; offset += csumBlockSize {
+ expCSum, err := LookupCSum(em.InFS, em.alg, mapping.LAddr.Add(offset))
+ if err != nil {
+ continue
+ }
+ actCSum, err := ChecksumPhysical(dev, em.alg, mapping.PAddr.Addr.Add(offset))
+ if err != nil {
+ return btrfsvol.Mapping{}, false
+ }
+ if actCSum != expCSum {
+ return btrfsvol.Mapping{}, false
+ }
+ }
+ return mapping, true
+}
+
+func (em *ExtentMappings) addMapping(sum shortSum, mapping btrfsvol.Mapping) {
+ em.internedMappingsMu.Lock()
+ interned := em.internedMappings[mapping]
+ if interned == nil {
+ interned = &mapping
+ em.internedMappings[mapping] = interned
+ }
+ em.internedMappingsMu.Unlock()
+
+ em.sum2lock[sum].Lock()
+ em.OutSum2mappings[sum] = append(em.OutSum2mappings[sum], interned)
+ em.sum2lock[sum].Unlock()
+}
+
+func (em *ExtentMappings) ScanOneDev(ctx context.Context, dev *btrfs.Device, gaps []PhysicalGap) error {
+ if err := em.init(); err != nil {
+ return err
+ }
+ devID := func() btrfsvol.DeviceID {
+ sb, _ := dev.Superblock()
+ return sb.DevItem.DevID
+ }()
+
+ dlog.Infof(ctx, "... dev[%q] Scanning for extents...", dev.Name())
+
+ sumSize := em.alg.Size()
+
+ lastProgress := -1
+ return WalkGapsOneDev(ctx, dev, gaps, csumBlockSize,
+ func(curBlock, totalBlocks int64) {
+ pct := int(100 * float64(curBlock) / float64(totalBlocks))
+ if pct != lastProgress || curBlock == totalBlocks {
+ dlog.Infof(ctx, "... dev[%q] scanned %v%%",
+ dev.Name(), pct)
+ lastProgress = pct
+ }
+ },
+ func(paddr btrfsvol.PhysicalAddr) error {
+ if err := ctx.Err(); err != nil {
+ return err
+ }
+ sum, err := ChecksumPhysical(dev, em.alg, paddr)
+ if err != nil {
+ dlog.Errorf(ctx, "... dev[%s] error: checksumming paddr=%v: %v",
+ dev.Name(), paddr, err)
+ return nil
+ }
+ shortSum := shortSum(sum[:sumSize])
+
+ for _, laddr := range em.InSum2laddrs[shortSum] {
+ if err := ctx.Err(); err != nil {
+ return err
+ }
+ mapping, ok := em.considerMapping(dev, laddr, btrfsvol.QualifiedPhysicalAddr{
+ Dev: devID,
+ Addr: paddr,
+ })
+ if !ok {
+ continue
+ }
+ em.addMapping(shortSum, mapping)
+ }
+
+ return nil
+ },
+ )
+}
diff --git a/lib/btrfsprogs/btrfsinspect/scanforextents/scanfornodes.go b/lib/btrfsprogs/btrfsinspect/scanforextents/scanfornodes.go
new file mode 100644
index 0000000..99009e6
--- /dev/null
+++ b/lib/btrfsprogs/btrfsinspect/scanforextents/scanfornodes.go
@@ -0,0 +1,101 @@
+// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package scanforextents
+
+import (
+ "encoding/json"
+ "fmt"
+ "os"
+
+ "git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
+ "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/containers"
+)
+
+type NodeScanResults = map[btrfsvol.DeviceID]btrfsinspect.ScanOneDevResult
+
+func ReadNodeScanResults(fs *btrfs.FS, filename string) (*BlockGroupTree, error) {
+ scanResultsBytes, err := os.ReadFile(filename)
+ if err != nil {
+ return nil, err
+ }
+
+ var scanResults NodeScanResults
+ if err := json.Unmarshal(scanResultsBytes, &scanResults); err != nil {
+ return nil, err
+ }
+
+ bgTree, err := ReduceScanResults(fs, scanResults)
+ if err != nil {
+ return nil, err
+ }
+
+ return bgTree, nil
+}
+
+type BlockGroup struct {
+ LAddr btrfsvol.LogicalAddr
+ Size btrfsvol.AddrDelta
+ Flags btrfsvol.BlockGroupFlags
+}
+
+type BlockGroupTree = containers.RBTree[containers.NativeOrdered[btrfsvol.LogicalAddr], BlockGroup]
+
+func LookupBlockGroup(tree *BlockGroupTree, laddr btrfsvol.LogicalAddr, size btrfsvol.AddrDelta) *BlockGroup {
+ a := struct {
+ LAddr btrfsvol.LogicalAddr
+ Size btrfsvol.AddrDelta
+ }{
+ LAddr: laddr,
+ Size: size,
+ }
+ node := tree.Search(func(b BlockGroup) int {
+ switch {
+ case a.LAddr.Add(a.Size) <= b.LAddr:
+ // 'a' is wholly to the left of 'b'.
+ return -1
+ case b.LAddr.Add(b.Size) <= a.LAddr:
+ // 'a' is wholly to the right of 'b'.
+ return 1
+ default:
+ // There is some overlap.
+ return 0
+ }
+ })
+ if node == nil {
+ return nil
+ }
+ bg := node.Value
+ return &bg
+}
+
+func ReduceScanResults(fs *btrfs.FS, scanResults NodeScanResults) (*BlockGroupTree, error) {
+ bgSet := make(map[BlockGroup]struct{})
+ for _, found := range scanResults {
+ for _, bg := range found.FoundBlockGroups {
+ bgSet[BlockGroup{
+ LAddr: btrfsvol.LogicalAddr(bg.Key.ObjectID),
+ Size: btrfsvol.AddrDelta(bg.Key.Offset),
+ Flags: bg.BG.Flags,
+ }] = struct{}{}
+ }
+ }
+ bgTree := &BlockGroupTree{
+ KeyFn: func(bg BlockGroup) containers.NativeOrdered[btrfsvol.LogicalAddr] {
+ return containers.NativeOrdered[btrfsvol.LogicalAddr]{Val: bg.LAddr}
+ },
+ }
+ for bg := range bgSet {
+ if laddr, _ := fs.LV.ResolveAny(bg.LAddr, bg.Size); laddr >= 0 {
+ continue
+ }
+ if LookupBlockGroup(bgTree, bg.LAddr, bg.Size) != nil {
+ return nil, fmt.Errorf("found block groups are inconsistent")
+ }
+ bgTree.Insert(bg)
+ }
+ return bgTree, nil
+}
--
cgit v1.2.3-2-g168b