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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package scanforextents
import (
"context"
"encoding/gob"
"fmt"
"io"
"os"
"runtime"
"strings"
"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/btrfsitem"
"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"
)
const csumBlockSize = 4 * 1024
type ShortSum string
type LogicalSumRun struct {
Addr btrfsvol.LogicalAddr
Sums string
}
type AllSums struct {
ChecksumSize int
Logical []LogicalSumRun
Physical map[btrfsvol.DeviceID]string
}
func ReadAllSums(filename string) (AllSums, error) {
fh, err := os.Open(filename)
if err != nil {
return AllSums{}, err
}
defer fh.Close()
var val AllSums
if err := gob.NewDecoder(fh).Decode(&val); err != nil {
return AllSums{}, err
}
return val, nil
}
func WriteAllSums(w io.Writer, sums AllSums) error {
return gob.NewEncoder(w).Encode(sums)
}
func (as AllSums) SumForPAddr(paddr btrfsvol.QualifiedPhysicalAddr) (ShortSum, bool) {
run, ok := as.Physical[paddr.Dev]
if !ok {
return "", false
}
off := int(paddr.Addr/csumBlockSize) * as.ChecksumSize
if off+as.ChecksumSize > len(run) {
return "", false
}
return ShortSum(run[off : off+as.ChecksumSize]), true
}
func (as AllSums) SumForLAddr(laddr btrfsvol.LogicalAddr) (ShortSum, bool) {
for _, run := range as.Logical {
size := btrfsvol.AddrDelta(len(run.Sums)/as.ChecksumSize) * csumBlockSize
if run.Addr > laddr {
return "", false
}
if run.Addr.Add(size) <= laddr {
continue
}
off := int(laddr.Sub(run.Addr)/csumBlockSize) * as.ChecksumSize
return ShortSum(run.Sums[off : off+as.ChecksumSize]), true
}
return "", false
}
func (as AllSums) WalkLogical(fn func(btrfsvol.LogicalAddr, ShortSum) error) error {
for _, run := range as.Logical {
for laddr, off := run.Addr, 0; off < len(run.Sums); laddr, off = laddr+csumBlockSize, off+as.ChecksumSize {
if err := fn(laddr, ShortSum(run.Sums[off:off+as.ChecksumSize])); err != nil {
return err
}
}
}
return nil
}
func SumEverything(ctx context.Context, fs *btrfs.FS) (AllSums, error) {
var ret AllSums
// ChecksumSize
var alg btrfssum.CSumType
if err := func() error {
sb, err := fs.Superblock()
if err != nil {
return err
}
alg = sb.ChecksumType
ret.ChecksumSize = alg.Size()
return nil
}(); err != nil {
return ret, err
}
// Logical
dlog.Info(ctx, "Walking CSUM_TREE...")
func() {
var curAddr btrfsvol.LogicalAddr
var curSums strings.Builder
btrfsutil.NewBrokenTrees(ctx, 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, sum := range body.Sums {
laddr := btrfsvol.LogicalAddr(item.Key.Offset) + (btrfsvol.LogicalAddr(i) * csumBlockSize)
if laddr != curAddr {
if curSums.Len() > 0 {
ret.Logical = append(ret.Logical, LogicalSumRun{
Addr: curAddr,
Sums: curSums.String(),
})
}
curAddr = laddr
curSums.Reset()
}
curSums.Write(sum[:ret.ChecksumSize])
}
return nil
},
},
)
if curSums.Len() > 0 {
ret.Logical = append(ret.Logical, LogicalSumRun{
Addr: curAddr,
Sums: curSums.String(),
})
}
}()
if err := ctx.Err(); err != nil {
return ret, err
}
dlog.Info(ctx, "... done walking")
runtime.GC()
dlog.Info(ctx, "... GC'd")
// Physical
dlog.Info(ctx, "Summing devices...")
if err := func() error {
devs := fs.LV.PhysicalVolumes()
var mu sync.Mutex
ret.Physical = make(map[btrfsvol.DeviceID]string, len(devs))
grp := dgroup.NewGroup(ctx, dgroup.GroupConfig{})
for devID, dev := range devs {
devID, dev := devID, dev
grp.Go(dev.Name(), func(ctx context.Context) error {
devSize := dev.Size()
numSums := int(devSize / csumBlockSize)
sums := make([]byte, numSums*ret.ChecksumSize)
lastPct := -1
progress := func(curSum int) {
pct := int(100 * float64(curSum) / float64(numSums))
if pct != lastPct || curSum == numSums {
dlog.Infof(ctx, "... dev[%q] summed %v%%",
dev.Name(), pct)
lastPct = pct
}
}
for i := 0; i < numSums; i++ {
if err := ctx.Err(); err != nil {
return err
}
progress(i)
sum, err := ChecksumPhysical(dev, alg, btrfsvol.PhysicalAddr(i*csumBlockSize))
if err != nil {
return err
}
copy(sums[i*ret.ChecksumSize:], sum[:ret.ChecksumSize])
}
progress(numSums)
sumsStr := string(sums)
mu.Lock()
ret.Physical[devID] = sumsStr
mu.Unlock()
return nil
})
}
return grp.Wait()
}(); err != nil {
return ret, err
}
dlog.Info(ctx, "... done summing devices")
runtime.GC()
dlog.Info(ctx, "... GC'd")
// Return
return ret, nil
}
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)
}
func LookupCSum(fs btrfs.Trees, alg btrfssum.CSumType, laddr btrfsvol.LogicalAddr) (map[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 nil, err
}
body, ok := item.Body.(btrfsitem.ExtentCSum)
if !ok {
return nil, fmt.Errorf("item body is %T not ExtentCSum", item.Body)
}
ret := make(map[btrfsvol.LogicalAddr]btrfssum.CSum, len(body.Sums))
for i, sum := range body.Sums {
ret[btrfsvol.LogicalAddr(item.Key.ObjectID)+(btrfsvol.LogicalAddr(i)*csumBlockSize)] = sum
}
return ret, nil
}
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