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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package main
import (
"bufio"
"io"
"os"
"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/btrfsprogs/btrfsinspect/rebuildmappings"
)
func init() {
inspectors = append(inspectors, subcommand{
Command: cobra.Command{
Use: "rebuild-mappings SCAN_RESULT.json",
Short: "Rebuild broken chunk/dev-extent/blockgroup trees",
Long: "" +
"The rebuilt information is printed as JSON on stdout, and can\n" +
"be loaded by the --mappings flag.\n" +
"\n" +
"This is very similar to `btrfs rescue chunk-recover`, but (1)\n" +
"does a better job, (2) is less buggy, and (3) doesn't actually\n" +
"write the info back to the filesystem; instead writing it\n" +
"out-of-band to stdout.",
Args: cliutil.WrapPositionalArgs(cobra.ExactArgs(1)),
},
RunE: func(fs *btrfs.FS, cmd *cobra.Command, args []string) error {
ctx := cmd.Context()
dlog.Infof(ctx, "Reading %q...", args[0])
scanResults, err := readScanResults(args[0])
if err != nil {
return err
}
dlog.Infof(ctx, "... done reading %q", args[0])
if err := rebuildmappings.RebuildMappings(ctx, fs, scanResults); err != nil {
return err
}
dlog.Infof(ctx, "Writing reconstructed mappings to stdout...")
if err := writeMappingsJSON(os.Stdout, fs); err != nil {
return err
}
dlog.Info(ctx, "... done writing")
return nil
},
})
}
func writeMappingsJSON(w io.Writer, fs *btrfs.FS) (err error) {
buffer := bufio.NewWriter(w)
defer func() {
if _err := buffer.Flush(); err == nil && _err != nil {
err = _err
}
}()
return lowmemjson.Encode(&lowmemjson.ReEncoder{
Out: buffer,
Indent: "\t",
ForceTrailingNewlines: true,
CompactIfUnder: 120,
}, fs.LV.Mappings())
}
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