cmd/btrfs-rec: Smash scandevices and rebuild-mappings together

5 files changed, 97 insertions, 78 deletions

diff --git a/cmd/btrfs-rec/inspect_lstrees.go b/cmd/btrfs-rec/inspect_lstrees.go
index be72860..1ff7671 100644
--- a/cmd/btrfs-rec/inspect_lstrees.go
+++ b/cmd/btrfs-rec/inspect_lstrees.go
@@ -114,7 +114,7 @@ func init() {
 			return nil
 		}),
 	}
-	cmd.Flags().StringVar(&scandevicesFilename, "scandevices", "", "Output of 'scandevices' to use for a lost+found tree")
+	cmd.Flags().StringVar(&scandevicesFilename, "scandevices", "", "Output of 'btrfs-recs inspect rebuild-mappings scan' to use for a lost+found tree")
 	noError(cmd.MarkFlagFilename("scandevices"))
 
 	inspectors.AddCommand(cmd)
diff --git a/cmd/btrfs-rec/inspect_rebuildmappings.go b/cmd/btrfs-rec/inspect_rebuildmappings.go
index 81660b0..55e3408 100644
--- a/cmd/btrfs-rec/inspect_rebuildmappings.go
+++ b/cmd/btrfs-rec/inspect_rebuildmappings.go
@@ -17,8 +17,8 @@ import (
 )
 
 func init() {
-	inspectors.AddCommand(&cobra.Command{
-		Use:   "rebuild-mappings SCAN_RESULT.json",
+	cmd := &cobra.Command{
+		Use:   "rebuild-mappings",
 		Short: "Rebuild broken chunk/dev-extent/blockgroup trees",
 		Long: "" +
 			"The rebuilt information is printed as JSON on stdout, and can\n" +
@@ -27,8 +27,69 @@ func init() {
 			"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)),
+			"out-of-band to stdout.\n" +
+			"\n" +
+			"The I/O and the CPU parts of this can be split up as:\n" +
+			"\n" +
+			"\tbtrfs-rec inspect rebuild-mappings scan > SCAN.json   # read\n" +
+			"\tbtrfs-rec inspect rebuild-mappings process SCAN.json  # CPU\n",
+		Args: cliutil.WrapPositionalArgs(cobra.NoArgs),
+		RunE: runWithRawFS(func(fs *btrfs.FS, cmd *cobra.Command, args []string) error {
+			ctx := cmd.Context()
+
+			scanResults, err := rebuildmappings.ScanDevices(ctx, fs)
+			if err != nil {
+				return err
+			}
+
+			if err := rebuildmappings.RebuildMappings(ctx, fs, scanResults); err != nil {
+				return err
+			}
+
+			dlog.Infof(ctx, "Writing reconstructed mappings to stdout...")
+			if err := writeJSONFile(os.Stdout, fs.LV.Mappings(), lowmemjson.ReEncoderConfig{
+				Indent:                "\t",
+				ForceTrailingNewlines: true,
+				CompactIfUnder:        120, //nolint:gomnd // This is what looks nice.
+			}); err != nil {
+				return err
+			}
+			dlog.Info(ctx, "... done writing")
+
+			return nil
+		}),
+	}
+
+	cmd.AddCommand(&cobra.Command{
+		Use:   "scan",
+		Short: "Read from the filesystem all data nescessary to rebuild the mappings",
+		Args:  cliutil.WrapPositionalArgs(cobra.NoArgs),
+		RunE: runWithRawFS(func(fs *btrfs.FS, cmd *cobra.Command, _ []string) (err error) {
+			ctx := cmd.Context()
+
+			scanResults, err := rebuildmappings.ScanDevices(ctx, fs)
+			if err != nil {
+				return err
+			}
+
+			dlog.Info(ctx, "Writing scan results to stdout...")
+			if err := writeJSONFile(os.Stdout, scanResults, lowmemjson.ReEncoderConfig{
+				Indent:                "\t",
+				ForceTrailingNewlines: true,
+				CompactIfUnder:        16, //nolint:gomnd // This is what looks nice.
+			}); err != nil {
+				return err
+			}
+			dlog.Info(ctx, "... done writing")
+
+			return nil
+		}),
+	})
+
+	cmd.AddCommand(&cobra.Command{
+		Use:   "process",
+		Short: "Rebuild the mappings based on previously read data",
+		Args:  cliutil.WrapPositionalArgs(cobra.ExactArgs(1)),
 		RunE: runWithRawFS(func(fs *btrfs.FS, cmd *cobra.Command, args []string) error {
 			ctx := cmd.Context()
 
@@ -56,4 +117,6 @@ func init() {
 			return nil
 		}),
 	})
+
+	inspectors.AddCommand(cmd)
 }
diff --git a/cmd/btrfs-rec/inspect_scandevices.go b/cmd/btrfs-rec/inspect_scandevices.go
deleted file mode 100644
index 4172c7c..0000000
--- a/cmd/btrfs-rec/inspect_scandevices.go
+++ /dev/null
@@ -1,69 +0,0 @@
-// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
-//
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-package main
-
-import (
-	"context"
-	"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/cmd/btrfs-rec/inspect/rebuildmappings"
-	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
-	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
-	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
-	"git.lukeshu.com/btrfs-progs-ng/lib/maps"
-)
-
-func init() {
-	inspectors.AddCommand(&cobra.Command{
-		Use:  "scandevices",
-		Args: cliutil.WrapPositionalArgs(cobra.NoArgs),
-		RunE: runWithRawFS(func(fs *btrfs.FS, cmd *cobra.Command, _ []string) (err error) {
-			ctx := cmd.Context()
-
-			results, err := rebuildmappings.ScanDevices(ctx, fs)
-			if err != nil {
-				return err
-			}
-
-			dlog.Info(ctx, "Writing scan results to stdout...")
-			if err := writeJSONFile(os.Stdout, results, lowmemjson.ReEncoderConfig{
-				Indent:                "\t",
-				ForceTrailingNewlines: true,
-				CompactIfUnder:        16, //nolint:gomnd // This is what looks nice.
-			}); err != nil {
-				return err
-			}
-			dlog.Info(ctx, "... done writing")
-
-			return nil
-		}),
-	})
-}
-
-func readNodeList(ctx context.Context, filename string) ([]btrfsvol.LogicalAddr, error) {
-	if filename == "" {
-		return nil, nil
-	}
-	results, err := readJSONFile[rebuildmappings.ScanDevicesResult](ctx, filename)
-	if err != nil {
-		return nil, err
-	}
-	var cnt int
-	for _, devResults := range results {
-		cnt += len(devResults.FoundNodes)
-	}
-	set := make(containers.Set[btrfsvol.LogicalAddr], cnt)
-	for _, devResults := range results {
-		for laddr := range devResults.FoundNodes {
-			set.Insert(laddr)
-		}
-	}
-	return maps.SortedKeys(set), nil
-}
diff --git a/cmd/btrfs-rec/util.go b/cmd/btrfs-rec/util.go
index 3d751a6..2e4bb84 100644
--- a/cmd/btrfs-rec/util.go
+++ b/cmd/btrfs-rec/util.go
@@ -13,6 +13,10 @@ import (
 	"git.lukeshu.com/go/lowmemjson"
 	"github.com/datawire/dlib/dlog"
 
+	"git.lukeshu.com/btrfs-progs-ng/cmd/btrfs-rec/inspect/rebuildmappings"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
+	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
+	"git.lukeshu.com/btrfs-progs-ng/lib/maps"
 	"git.lukeshu.com/btrfs-progs-ng/lib/streamio"
 )
 
@@ -47,3 +51,24 @@ func writeJSONFile(w io.Writer, obj any, cfg lowmemjson.ReEncoderConfig) (err er
 	}()
 	return lowmemjson.NewEncoder(lowmemjson.NewReEncoder(buffer, cfg)).Encode(obj)
 }
+
+func readNodeList(ctx context.Context, filename string) ([]btrfsvol.LogicalAddr, error) {
+	if filename == "" {
+		return nil, nil
+	}
+	results, err := readJSONFile[rebuildmappings.ScanDevicesResult](ctx, filename)
+	if err != nil {
+		return nil, err
+	}
+	var cnt int
+	for _, devResults := range results {
+		cnt += len(devResults.FoundNodes)
+	}
+	set := make(containers.Set[btrfsvol.LogicalAddr], cnt)
+	for _, devResults := range results {
+		for laddr := range devResults.FoundNodes {
+			set.Insert(laddr)
+		}
+	}
+	return maps.SortedKeys(set), nil
+}
diff --git a/scripts/main.sh b/scripts/main.sh
index 4aa96ea..67fb330 100755
--- a/scripts/main.sh
+++ b/scripts/main.sh
@@ -32,9 +32,9 @@ export GOMEMLIMIT="$(awk '/^MemTotal:/{ print $2 "KiB" }' </proc/meminfo)"
 ######################################################################
 
 run-btrfs-rec $gendir/0.scandevices.json \
-    inspect scandevices
+    inspect rebuild-mappings scan
 run-btrfs-rec $gendir/1.mappings.json \
-    inspect rebuild-mappings $gendir/0.scandevices.json
+    inspect rebuild-mappings process $gendir/0.scandevices.json
 
 # 1.mappings.log says:
 #
@@ -52,13 +52,13 @@ run-btrfs-rec $gendir/1.mappings.json \
 # matter which order we put the 2 block groups in within that physical
 # region.  So just put them in laddr order.
 #
-# And then run that through `rebuild-mappings` again to fill in the
+# And then run that through `rebuild-mappings process` again to fill in the
 # flags and normalize it.
 run-btrfs-rec $gendir/2.mappings.json \
     --mappings=<(sed <$gendir/1.mappings.json \
       -e '2a{"LAddr":5242880,"PAddr":{"Dev":1,"Addr":5242880},"Size":1},' \
       -e '2a{"LAddr":13631488,"PAddr":{"Dev":1,"Addr":13631488},"Size":1},') \
-    inspect rebuild-mappings $gendir/0.scandevices.json
+    inspect rebuild-mappings process $gendir/0.scandevices.json
 
 run-btrfs-rec $gendir/3.nodes.json \
     --mappings=$gendir/2.mappings.json \