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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package main
import (
"bufio"
"fmt"
"os"
"strings"
"git.lukeshu.com/go/lowmemjson"
"github.com/datawire/dlib/dlog"
"github.com/datawire/ocibuild/pkg/cliutil"
"github.com/spf13/cobra"
"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"
)
func init() {
inspectors = append(inspectors, subcommand{
Command: cobra.Command{
Use: "dbgsums SCAN_RESULT.json",
Args: cliutil.WrapPositionalArgs(cobra.ExactArgs(1)),
},
RunE: func(fs *btrfs.FS, cmd *cobra.Command, args []string) (err error) {
maybeSetErr := func(_err error) {
if err == nil && _err != nil {
err = _err
}
}
ctx := cmd.Context()
dlog.Infof(ctx, "Reading %q...", args[0])
scanResults, err := func() (btrfsinspect.ScanDevicesResult, error) {
fh, err := os.Open(args[0])
if err != nil {
return nil, err
}
var scanResults btrfsinspect.ScanDevicesResult
buf := bufio.NewReader(fh)
if err := lowmemjson.DecodeThenEOF(buf, &scanResults); err != nil {
return nil, err
}
_ = fh.Close()
return scanResults, nil
}()
dlog.Infof(ctx, "... done reading %q", args[0])
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
})
}
}
if len(addrspace) == 0 {
return fmt.Errorf("no checksums were found in the scan")
}
dlog.Info(ctx, "... done mapping")
dlog.Info(ctx, "Flattening the map ...")
var flattened btrfssum.SumRunWithGaps[btrfsvol.LogicalAddr]
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")
dlog.Info(ctx, "Writing addrspace sums to stdout...")
buffer := bufio.NewWriter(os.Stdout)
defer func() {
maybeSetErr(buffer.Flush())
}()
return lowmemjson.Encode(&lowmemjson.ReEncoder{
Out: buffer,
Indent: "\t",
ForceTrailingNewlines: true,
}, flattened)
},
})
}
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