cmd/geth: graceful shutdown if disk is full (ethereum#22103)

Adding warnings of free disk space left and graceful shutdown when there is not enough space left.
This also adds a flag datadir.minfreedisk which can be used to set the trigger for low disk space, and setting it to zero disables the check. 

Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Felix Lange <fjl@twurst.com>

cmd/geth/main.go

@@ -65,6 +65,7 @@ var (
 		utils.LegacyBootnodesV5Flag,
 		utils.DataDirFlag,
 		utils.AncientFlag,
+		utils.MinFreeDiskSpaceFlag,
 		utils.KeyStoreDirFlag,
 		utils.ExternalSignerFlag,
 		utils.NoUSBFlag,
@@ -368,7 +369,7 @@ func startNode(ctx *cli.Context, stack *node.Node, backend ethapi.Backend) {
 	debug.Memsize.Add("node", stack)
 
 	// Start up the node itself
-	utils.StartNode(stack)
+	utils.StartNode(ctx, stack)
 
 	// Unlock any account specifically requested
 	unlockAccounts(ctx, stack)

cmd/geth/usage.go

@@ -36,6 +36,7 @@ var AppHelpFlagGroups = []flags.FlagGroup{
 			configFileFlag,
 			utils.DataDirFlag,
 			utils.AncientFlag,
+			utils.MinFreeDiskSpaceFlag,
 			utils.KeyStoreDirFlag,
 			utils.USBFlag,
 			utils.SmartCardDaemonPathFlag,

cmd/utils/cmd.go

@@ -26,17 +26,20 @@ import (
 	"runtime"
 	"strings"
 	"syscall"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/internal/debug"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/node"
 	"github.com/ethereum/go-ethereum/rlp"
+	"gopkg.in/urfave/cli.v1"
 )
 
 const (
@@ -63,14 +66,25 @@ func Fatalf(format string, args ...interface{}) {
 	os.Exit(1)
 }
 
-func StartNode(stack *node.Node) {
+func StartNode(ctx *cli.Context, stack *node.Node) {
 	if err := stack.Start(); err != nil {
 		Fatalf("Error starting protocol stack: %v", err)
 	}
 	go func() {
 		sigc := make(chan os.Signal, 1)
 		signal.Notify(sigc, syscall.SIGINT, syscall.SIGTERM)
 		defer signal.Stop(sigc)
+
+		minFreeDiskSpace := eth.DefaultConfig.TrieDirtyCache
+		if ctx.GlobalIsSet(MinFreeDiskSpaceFlag.Name) {
+			minFreeDiskSpace = ctx.GlobalInt(MinFreeDiskSpaceFlag.Name)
+		} else if ctx.GlobalIsSet(CacheFlag.Name) || ctx.GlobalIsSet(CacheGCFlag.Name) {
+			minFreeDiskSpace = ctx.GlobalInt(CacheFlag.Name) * ctx.GlobalInt(CacheGCFlag.Name) / 100
+		}
+		if minFreeDiskSpace > 0 {
+			go monitorFreeDiskSpace(sigc, stack.InstanceDir(), uint64(minFreeDiskSpace)*1024*1024)
+		}
+
 		<-sigc
 		log.Info("Got interrupt, shutting down...")
 		go stack.Close()
@@ -85,6 +99,24 @@ func StartNode(stack *node.Node) {
 	}()
 }
 
+func monitorFreeDiskSpace(sigc chan os.Signal, path string, freeDiskSpaceCritical uint64) {
+	for {
+		freeSpace, err := getFreeDiskSpace(path)
+		if err != nil {
+			log.Warn("Failed to get free disk space", "path", path, "err", err)
+			break
+		}
+		if freeSpace < freeDiskSpaceCritical {
+			log.Error("Low disk space. Gracefully shutting down Geth to prevent database corruption.", "available", common.StorageSize(freeSpace))
+			sigc <- syscall.SIGTERM
+			break
+		} else if freeSpace < 2*freeDiskSpaceCritical {
+			log.Warn("Disk space is running low. Geth will shutdown if disk space runs below critical level.", "available", common.StorageSize(freeSpace), "critical_level", common.StorageSize(freeDiskSpaceCritical))
+		}
+		time.Sleep(60 * time.Second)
+	}
+}
+
 func ImportChain(chain *core.BlockChain, fn string) error {
 	// Watch for Ctrl-C while the import is running.
 	// If a signal is received, the import will stop at the next batch.

cmd/utils/diskusage.go

@@ -0,0 +1,35 @@
+// Copyright 2021 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// +build !windows
+
+package utils
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+func getFreeDiskSpace(path string) (uint64, error) {
+	var stat unix.Statfs_t
+	if err := unix.Statfs(path, &stat); err != nil {
+		return 0, fmt.Errorf("failed to call Statfs: %v", err)
+	}
+
+	// Available blocks * size per block = available space in bytes
+	return stat.Bavail * uint64(stat.Bsize), nil
+}

cmd/utils/diskusage_windows.go

@@ -0,0 +1,38 @@
+// Copyright 2021 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package utils
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/windows"
+)
+
+func getFreeDiskSpace(path string) (uint64, error) {
+
+	cwd, err := windows.UTF16PtrFromString(path)
+	if err != nil {
+		return 0, fmt.Errorf("failed to call UTF16PtrFromString: %v", err)
+	}
+
+	var freeBytesAvailableToCaller, totalNumberOfBytes, totalNumberOfFreeBytes uint64
+	if err := windows.GetDiskFreeSpaceEx(cwd, &freeBytesAvailableToCaller, &totalNumberOfBytes, &totalNumberOfFreeBytes); err != nil {
+		return 0, fmt.Errorf("failed to call GetDiskFreeSpaceEx: %v", err)
+	}
+
+	return freeBytesAvailableToCaller, nil
+}

cmd/utils/flags.go

@@ -113,6 +113,10 @@ var (
 		Name:  "datadir.ancient",
 		Usage: "Data directory for ancient chain segments (default = inside chaindata)",
 	}
+	MinFreeDiskSpaceFlag = DirectoryFlag{
+		Name:  "datadir.minfreedisk",
+		Usage: "Minimum free disk space in MB, once reached triggers auto shut down (default = --cache.gc converted to MB, 0 = disabled)",
+	}
 	KeyStoreDirFlag = DirectoryFlag{
 		Name:  "keystore",
 		Usage: "Directory for the keystore (default = inside the datadir)",