mount: restart mount process gracefully

cmd/mount.go

@@ -18,25 +18,21 @@ package cmd
 
 import (
 	"bufio"
-	"encoding/json"
 	"fmt"
 	"log"
 	"net"
 	"net/http"
 	_ "net/http/pprof"
 	"os"
-	"os/signal"
 	"path"
 	"path/filepath"
 	"runtime"
 	"sort"
 	"strconv"
 	"strings"
-	"syscall"
 	"time"
 
 	"github.com/juicedata/juicefs/pkg/object"
-
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/collectors"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -81,29 +77,10 @@ $ juicefs mount redis://localhost /mnt/jfs -d --read-only
 
 # Disable metadata backup
 $ juicefs mount redis://localhost /mnt/jfs --backup-meta 0`,
-		Flags: expandFlags(mount_flags(), clientFlags(1.0), shareInfoFlags()),
+		Flags: expandFlags(mountFlags(), clientFlags(1.0), shareInfoFlags()),
 	}
 }
 
-func installHandler(mp string) {
-	// Go will catch all the signals
-	signal.Ignore(syscall.SIGPIPE)
-	signalChan := make(chan os.Signal, 10)
-	signal.Notify(signalChan, syscall.SIGTERM, syscall.SIGINT, syscall.SIGHUP)
-	go func() {
-		for {
-			sig := <-signalChan
-			logger.Infof("Received signal %s, exiting...", sig.String())
-			go func() { _ = doUmount(mp, true) }()
-			go func() {
-				time.Sleep(time.Second * 3)
-				logger.Warnf("Umount not finished after 3 seconds, force exit")
-				os.Exit(1)
-			}()
-		}
-	}()
-}
-
 func exposeMetrics(c *cli.Context, registerer prometheus.Registerer, registry *prometheus.Registry) string {
 	var ip, port string
 	//default set
@@ -207,7 +184,7 @@ func updateFormat(c *cli.Context) func(*meta.Format) {
 	}
 }
 
-func daemonRun(c *cli.Context, addr string, vfsConf *vfs.Config, m meta.Meta) {
+func daemonRun(c *cli.Context, addr string, vfsConf *vfs.Config) {
 	if runtime.GOOS != "windows" {
 		if cd := c.String("cache-dir"); cd != "memory" {
 			ds := utils.SplitDir(cd)
@@ -238,7 +215,7 @@ func daemonRun(c *cli.Context, addr string, vfsConf *vfs.Config, m meta.Meta) {
 	_ = expandPathForEmbedded(addr)
 	// The default log to syslog is only in daemon mode.
 	utils.InitLoggers(!c.Bool("no-syslog"))
-	err := makeDaemon(c, vfsConf.Format.Name, vfsConf.Meta.MountPoint, m)
+	err := makeDaemon(c, vfsConf)
 	if err != nil {
 		logger.Fatalf("Failed to make daemon: %s", err)
 	}
@@ -276,6 +253,8 @@ func getVfsConf(c *cli.Context, metaConf *meta.Config, format *meta.Format, chun
 		BackupMeta:     duration(c.String("backup-meta")),
 		Port:           &vfs.Port{DebugAgent: debugAgent, PyroscopeAddr: c.String("pyroscope")},
 		PrefixInternal: c.Bool("prefix-internal"),
+		Pid:            os.Getpid(),
+		PPid:           os.Getppid(),
 	}
 	skip_check := os.Getenv("SKIP_BACKUP_META_CHECK") == "true"
 	if !skip_check && cfg.BackupMeta > 0 && cfg.BackupMeta < time.Minute*5 {
@@ -293,31 +272,6 @@ func registerMetaMsg(m meta.Meta, store chunk.ChunkStore, chunkConf *chunk.Confi
 	})
 }
 
-func configEqual(a, b *vfs.Config) bool {
-	if a == nil || b == nil {
-		return a == b
-	}
-
-	ac, bc := *a, *b
-	ac.Meta, ac.Chunk, ac.Port, ac.Format.SecretKey, ac.AttrTimeout, ac.DirEntryTimeout, ac.EntryTimeout = nil, nil, nil, "", 0, 0, 0
-	bc.Meta, bc.Chunk, bc.Port, bc.Format.SecretKey, bc.AttrTimeout, bc.DirEntryTimeout, bc.EntryTimeout = nil, nil, nil, "", 0, 0, 0
-	eq := ac == bc
-
-	if a.Meta == nil || b.Meta == nil {
-		eq = eq && a.Meta == b.Meta
-	} else {
-		eq = eq && *a.Meta == *b.Meta
-	}
-
-	if a.Chunk == nil || b.Chunk == nil {
-		eq = eq && a.Chunk == b.Chunk
-	} else {
-		eq = eq && *a.Chunk == *b.Chunk
-	}
-
-	return eq
-}
-
 func readConfig(mp string) ([]byte, error) {
 	contents, err := os.ReadFile(filepath.Join(mp, ".jfs.config"))
 	if os.IsNotExist(err) {
@@ -326,56 +280,6 @@ func readConfig(mp string) ([]byte, error) {
 	return contents, err
 }
 
-func prepareMp(newCfg *vfs.Config, mp string) (ignore bool) {
-	fi, err := os.Stat(mp)
-	if err != nil {
-		if strings.Contains(mp, ":") {
-			// Windows path, users should inspect mount point by themselves
-			return
-		}
-		if err := os.MkdirAll(mp, 0777); err != nil {
-			if os.IsExist(err) {
-				// a broken mount point, umount it and continue to mount
-				_ = doUmount(mp, true)
-				return
-			}
-			logger.Fatalf("create %s: %s", mp, err)
-		}
-		return
-	}
-	if fi.Size() == 0 {
-		// a broken mount point, umount it and continue to mount
-		_ = doUmount(mp, true)
-		return
-	}
-
-	ino, _ := utils.GetFileInode(mp)
-	if ino != uint64(meta.RootInode) {
-		// not a mount point, just mount it
-		return
-	}
-
-	contents, err := readConfig(mp)
-	if err != nil {
-		// failed to read juicefs config, continue to mount
-		return
-	}
-
-	originConfig := vfs.Config{}
-	if err = json.Unmarshal(contents, &originConfig); err != nil {
-		// not a valid juicefs config, continue to mount
-		return
-	}
-
-	if !configEqual(newCfg, &originConfig) {
-		// not the same juicefs, continue to mount
-		return
-	}
-
-	logger.Warnf("%s is already mounted by the same juicefs, ignored", mp)
-	return true
-}
-
 func getMetaConf(c *cli.Context, mp string, readOnly bool) *meta.Config {
 	conf := meta.DefaultConf()
 	conf.Retries = c.Int("io-retries")
@@ -389,6 +293,7 @@ func getMetaConf(c *cli.Context, mp string, readOnly bool) *meta.Config {
 	conf.MountPoint = mp
 	conf.Subdir = c.String("subdir")
 	conf.SkipDirMtime = duration(c.String("skip-dir-mtime"))
+	conf.Sid, _ = strconv.ParseUint(os.Getenv("_JFS_META_SID"), 10, 64)
 
 	atimeMode := c.String("atime-mode")
 	if atimeMode != meta.RelAtime && atimeMode != meta.StrictAtime && atimeMode != meta.NoAtime {
@@ -626,17 +531,83 @@ func mount(c *cli.Context) error {
 	addr := c.Args().Get(0)
 	mp := c.Args().Get(1)
 
+	// __DAEMON_STAGE env is set by the godaemon.MakeDaemon function
+	supervisor := os.Getenv("JFS_SUPERVISOR")
+	inFirstProcess := supervisor == "test" || supervisor == "" && os.Getenv("__DAEMON_STAGE") == ""
+	if inFirstProcess {
+		var err error
+		err = utils.WithTimeout(func() error {
+			mp, err = filepath.Abs(mp)
+			return err
+		}, time.Second*3)
+		if err != nil {
+			logger.Fatalf("abs %s: %s", mp, err)
+		}
+		if mp == "/" {
+			logger.Fatalf("should not mount on the root directory")
+		}
+		prepareMp(mp)
+		if c.Bool("update-fstab") && !calledViaMount(os.Args) && !insideContainer() {
+			if os.Getuid() != 0 {
+				logger.Warnf("--update-fstab should be used with root")
+			} else {
+				var e1, e2 error
+				if e1 = tryToInstallMountExec(); e1 != nil {
+					logger.Warnf("failed to create /sbin/mount.juicefs: %s", e1)
+				}
+				if e2 = updateFstab(c); e2 != nil {
+					logger.Warnf("failed to update fstab: %s", e2)
+				}
+				if e1 == nil && e2 == nil {
+					logger.Infof("Successfully updated fstab, now you can mount with `mount %s`", mp)
+				}
+			}
+		}
+	}
+
 	metaConf := getMetaConf(c, mp, c.Bool("read-only") || utils.StringContains(strings.Split(c.String("o"), ","), "ro"))
 	metaConf.CaseInsensi = strings.HasSuffix(mp, ":") && runtime.GOOS == "windows"
 	metaCli := meta.NewClient(addr, metaConf)
 	format, err := metaCli.Load(true)
 	if err != nil {
 		return err
 	}
+
+	chunkConf := getChunkConf(c, format)
+	vfsConf := getVfsConf(c, metaConf, format, chunkConf)
+	setFuseOption(c, format, vfsConf)
+
+	if os.Getenv("JFS_SUPERVISOR") == "" {
+		// close the database connection that is not in the final stage
+		if err = metaCli.Shutdown(); err != nil {
+			logger.Errorf("[pid=%d] meta shutdown: %s", os.Getpid(), err)
+		}
+		var foreground bool
+		if runtime.GOOS == "windows" || !c.Bool("background") || os.Getenv("JFS_FOREGROUND") != "" {
+			foreground = true
+		} else if c.Bool("background") || os.Getenv("__DAEMON_STAGE") != "" {
+			foreground = false
+		} else {
+			foreground = os.Getppid() == 1 && !insideContainer()
+		}
+		if foreground {
+			go checkMountpoint(format.Name, mp, c.String("log"), false)
+		} else {
+			daemonRun(c, addr, vfsConf)
+		}
+		os.Setenv("JFS_SUPERVISOR", strconv.Itoa(os.Getppid()))
+		return launchMount(mp, vfsConf)
+	}
+	logger.Infof("JuiceFS version %s", version.Version())
+
+	if commPath := os.Getenv("_FUSE_FD_COMM"); commPath != "" {
+		vfsConf.CommPath = commPath
+		vfsConf.StatePath = fmt.Sprintf("/tmp/state%d.json", os.Getppid())
+	}
+
 	if st := metaCli.Chroot(meta.Background, metaConf.Subdir); st != 0 {
 		return st
 	}
-
 	// Wrap the default registry, all prometheus.MustRegister() calls should be afterwards
 	registerer, registry := wrapRegister(c, mp, format.Name)
 
@@ -646,42 +617,9 @@ func mount(c *cli.Context) error {
 	}
 	logger.Infof("Data use %s", blob)
 
-	if c.Bool("update-fstab") && !calledViaMount(os.Args) && !insideContainer() {
-		if os.Getuid() != 0 {
-			logger.Warnf("--update-fstab should be used with root")
-		} else {
-			var e1, e2 error
-			if e1 = tryToInstallMountExec(); e1 != nil {
-				logger.Warnf("failed to create /sbin/mount.juicefs: %s", e1)
-			}
-			if e2 = updateFstab(c); e2 != nil {
-				logger.Warnf("failed to update fstab: %s", e2)
-			}
-			if e1 == nil && e2 == nil {
-				logger.Infof("Successfully updated fstab, now you can mount with `mount %s`", mp)
-			}
-		}
-	}
-
-	chunkConf := getChunkConf(c, format)
 	store := chunk.NewCachedStore(blob, *chunkConf, registerer)
 	registerMetaMsg(metaCli, store, chunkConf)
 
-	vfsConf := getVfsConf(c, metaConf, format, chunkConf)
-	ignore := prepareMp(vfsConf, mp)
-	if !c.Bool("force") && ignore {
-		return nil
-	}
-
-	if c.Bool("background") && os.Getenv("JFS_FOREGROUND") == "" {
-		daemonRun(c, addr, vfsConf, metaCli)
-	} else {
-		if c.IsSet("log") {
-			logger.Warnf("--log flag is ignored in foreground mode, the log output will be Stderr")
-		}
-		go checkMountpoint(vfsConf.Format.Name, mp, c.String("log"), false)
-	}
-
 	removePassword(addr)
 	err = metaCli.NewSession(true)
 	if err != nil {
@@ -692,11 +630,14 @@ func mount(c *cli.Context) error {
 		updateFormat(c)(fmt)
 		store.UpdateLimit(fmt.UploadLimit, fmt.DownloadLimit)
 	})
-	installHandler(mp)
 	v := vfs.NewVFS(vfsConf, metaCli, store, registerer, registry)
+	installHandler(mp, v)
 	v.UpdateFormat = updateFormat(c)
 	initBackgroundTasks(c, vfsConf, metaConf, metaCli, blob, registerer, registry)
-	mount_main(v, c)
+	mountMain(v, c)
+	if err := v.FlushAll(""); err != nil {
+		logger.Errorf("flush all delayed data: %s", err)
+	}
 	err = metaCli.CloseSession()
 	logger.Infof("The juicefs mount process exit successfully, mountpoint: %s", metaConf.MountPoint)
 	return err

cmd/mount_test.go

@@ -19,6 +19,8 @@ package cmd
 import (
 	"context"
 	"fmt"
+	"github.com/juicedata/juicefs/pkg/version"
+	"github.com/stretchr/testify/assert"
 	"io"
 	"net/http"
 	"net/url"
@@ -32,11 +34,9 @@ import (
 	"github.com/agiledragon/gomonkey/v2"
 	"github.com/juicedata/juicefs/pkg/meta"
 	"github.com/juicedata/juicefs/pkg/utils"
-	"github.com/juicedata/juicefs/pkg/version"
 	"github.com/juicedata/juicefs/pkg/vfs"
 	"github.com/redis/go-redis/v9"
 	. "github.com/smartystreets/goconvey/convey"
-	"github.com/stretchr/testify/assert"
 	"github.com/urfave/cli/v2"
 )
 
@@ -124,6 +124,7 @@ func mountTemp(t *testing.T, bucket *string, extraFormatOpts []string, extraMoun
 	// must do reset, otherwise will panic
 	ResetHttp()
 
+	os.Setenv("JFS_SUPERVISOR", "test")
 	mountArgs := []string{"", "mount", "--enable-xattr", testMeta, testMountPoint, "--attr-cache", "0", "--entry-cache", "0", "--dir-entry-cache", "0", "--no-usage-report"}
 	if extraMountOpts != nil {
 		mountArgs = append(mountArgs, extraMountOpts...)
@@ -204,38 +205,6 @@ func TestUmount(t *testing.T) {
 	}
 }
 
-func Test_configEqual(t *testing.T) {
-	cases := []struct {
-		a, b  *vfs.Config
-		equal bool
-	}{
-		{
-			a: nil, b: nil, equal: true,
-		},
-		{
-			a: &vfs.Config{}, b: nil, equal: false,
-		},
-		{
-			a: nil, b: &vfs.Config{}, equal: false,
-		},
-		{
-			a: &vfs.Config{}, b: &vfs.Config{}, equal: true,
-		},
-		{
-			a: &vfs.Config{Format: meta.Format{SecretKey: "1"}}, b: &vfs.Config{Format: meta.Format{SecretKey: "2"}}, equal: true,
-		},
-		{
-			a: &vfs.Config{Port: &vfs.Port{}}, b: &vfs.Config{}, equal: true,
-		},
-	}
-
-	for _, c := range cases {
-		if configEqual(c.a, c.b) != c.equal {
-			t.Errorf("configEqual(%v, %v) should be %v", c.a, c.b, c.equal)
-		}
-	}
-}
-
 func tryMountTemp(t *testing.T, bucket *string, extraFormatOpts []string, extraMountOpts []string) error {
 	_ = resetTestMeta()
 	testDir := t.TempDir()