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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package rebuildmappings
import (
"context"
"strings"
"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/btrfsinspect"
"git.lukeshu.com/btrfs-progs-ng/lib/maps"
"git.lukeshu.com/btrfs-progs-ng/lib/slices"
)
func MapLogicalSums(ctx context.Context, scanResults btrfsinspect.ScanDevicesResult) btrfssum.SumRunWithGaps[btrfsvol.LogicalAddr] {
dlog.Info(ctx, "Mapping the logical address space...")
type record struct {
Gen btrfs.Generation
Sum btrfssum.ShortSum
}
addrspace := make(map[btrfsvol.LogicalAddr]record)
var sumSize int
for _, devResults := range scanResults {
sumSize = devResults.Checksums.ChecksumSize
for _, sumItem := range devResults.FoundExtentCSums {
_ = sumItem.Sums.Walk(ctx, func(pos btrfsvol.LogicalAddr, sum btrfssum.ShortSum) error {
new := record{
Gen: sumItem.Generation,
Sum: sum,
}
if old, ok := addrspace[pos]; ok {
switch {
case old.Gen > new.Gen:
// do nothing
case old.Gen < new.Gen:
addrspace[pos] = new
case old.Gen == new.Gen:
if old != new {
dlog.Errorf(ctx, "mismatch of laddr=%v sum: %v != %v", pos, old, new)
}
}
} else {
addrspace[pos] = new
}
return nil
})
}
}
dlog.Info(ctx, "... done mapping")
var flattened btrfssum.SumRunWithGaps[btrfsvol.LogicalAddr]
if len(addrspace) == 0 {
return flattened
}
dlog.Info(ctx, "Flattening the map ...")
var curAddr btrfsvol.LogicalAddr
var curSums strings.Builder
for _, laddr := range maps.SortedKeys(addrspace) {
if laddr != curAddr+(btrfsvol.LogicalAddr(curSums.Len()/sumSize)*btrfssum.BlockSize) {
if curSums.Len() > 0 {
flattened.Runs = append(flattened.Runs, btrfssum.SumRun[btrfsvol.LogicalAddr]{
ChecksumSize: sumSize,
Addr: curAddr,
Sums: btrfssum.ShortSum(curSums.String()),
})
}
curAddr = laddr
curSums.Reset()
}
curSums.WriteString(string(addrspace[laddr].Sum))
}
if curSums.Len() > 0 {
flattened.Runs = append(flattened.Runs, btrfssum.SumRun[btrfsvol.LogicalAddr]{
ChecksumSize: sumSize,
Addr: curAddr,
Sums: btrfssum.ShortSum(curSums.String()),
})
}
flattened.Addr = flattened.Runs[0].Addr
last := flattened.Runs[len(flattened.Runs)-1]
end := last.Addr.Add(last.Size())
flattened.Size = end.Sub(flattened.Addr)
dlog.Info(ctx, "... done flattening")
return flattened
}
func SumsForLogicalRegion(sums btrfssum.SumRunWithGaps[btrfsvol.LogicalAddr], beg btrfsvol.LogicalAddr, size btrfsvol.AddrDelta) btrfssum.SumRunWithGaps[btrfsvol.LogicalAddr] {
runs := btrfssum.SumRunWithGaps[btrfsvol.LogicalAddr]{
Addr: beg,
Size: size,
}
for laddr := beg; laddr < beg.Add(size); {
run, next, ok := sums.RunForAddr(laddr)
if !ok {
laddr = next
continue
}
off := int((laddr-run.Addr)/btrfssum.BlockSize) * run.ChecksumSize
deltaAddr := slices.Min[btrfsvol.AddrDelta](
size-laddr.Sub(beg),
btrfsvol.AddrDelta((len(run.Sums)-off)/run.ChecksumSize)*btrfssum.BlockSize)
deltaOff := int(deltaAddr/btrfssum.BlockSize) * run.ChecksumSize
runs.Runs = append(runs.Runs, btrfssum.SumRun[btrfsvol.LogicalAddr]{
ChecksumSize: run.ChecksumSize,
Addr: laddr,
Sums: run.Sums[off : off+deltaOff],
})
laddr = laddr.Add(deltaAddr)
}
return runs
}
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