Mount on non-empty path (#1311)

CHANGELOG.md

@@ -2,6 +2,7 @@
 **Bug Fixes**
 - Invalidate attribute cache entry on `PathAlreadyExists` error in create directory operation.
 - When `$HOME` environment variable is not present, use the current directory.
+- Fixed mount failure on nonempty mount path for fuse3.
 
 **Features**
 - Support CPK for block storage accounts.

azure-pipeline-templates/build.yml

@@ -35,6 +35,7 @@ steps:
   - script: |
       sudo apt-get update --fix-missing
       sudo apt-get install ${{ parameters.fuselib }} -y
+      fusermount -V
     displayName: 'Libfuse Setup'
     condition: eq('${{ parameters.hostedAgent }}', true)
 

blobfuse2-nightly.yaml

@@ -139,6 +139,9 @@ stages:
             - script: |
                 sudo apt-get update --fix-missing
                 sudo apt-get install $(fuselib) -y
+                if [ $(tags) == "fuse2" ]; then
+                  sudo apt-get install fuse -y
+                fi
               displayName: 'Install libfuse'
 
             # -------------------------------------------------------
@@ -412,6 +415,9 @@ stages:
             - script: |
                 sudo apt-get update --fix-missing
                 sudo apt-get install $(fuselib) -y
+                if [ $(tags) == "fuse2" ]; then
+                  sudo apt-get install fuse -y
+                fi
               displayName: 'Install libfuse'
 
             # -------------------------------------------------------

cmd/mount.go

@@ -97,7 +97,7 @@ type mountOptions struct {
 
 var options mountOptions
 
-func (opt *mountOptions) validate(skipEmptyMount bool) error {
+func (opt *mountOptions) validate(skipNonEmptyMount bool) error {
 	if opt.MountPath == "" {
 		return fmt.Errorf("mount path not provided")
 	}
@@ -106,7 +106,7 @@ func (opt *mountOptions) validate(skipEmptyMount bool) error {
 		return fmt.Errorf("mount directory does not exists")
 	} else if common.IsDirectoryMounted(opt.MountPath) {
 		return fmt.Errorf("directory is already mounted")
-	} else if !skipEmptyMount && !common.IsDirectoryEmpty(opt.MountPath) {
+	} else if !skipNonEmptyMount && !common.IsDirectoryEmpty(opt.MountPath) {
 		return fmt.Errorf("mount directory is not empty")
 	}
 
@@ -285,8 +285,6 @@ var mountCmd = &cobra.Command{
 			options.Components = pipeline
 		}
 
-		skipNonEmpty := false
-
 		if config.IsSet("libfuse-options") {
 			for _, v := range options.LibfuseOptions {
 				parameter := strings.Split(v, "=")
@@ -309,8 +307,11 @@ var mountCmd = &cobra.Command{
 					config.Set("read-only", "true")
 				} else if v == "allow_root" || v == "allow_root=true" {
 					config.Set("allow-root", "true")
-				} else if v == "nonempty" {
-					skipNonEmpty = true
+				} else if v == "nonempty" || v == "nonempty=true" {
+					// For fuse3, -o nonempty mount option has been removed and
+					// mounting over non-empty directories is now always allowed.
+					// For fuse2, this option is supported.
+					options.NonEmpty = true
 					config.Set("nonempty", "true")
 				} else if strings.HasPrefix(v, "umask=") {
 					umask, err := strconv.ParseUint(parameter[1], 10, 32)
@@ -346,7 +347,7 @@ var mountCmd = &cobra.Command{
 			options.Logging.LogLevel = "LOG_WARNING"
 		}
 
-		err = options.validate(options.NonEmpty || skipNonEmpty)
+		err = options.validate(options.NonEmpty)
 		if err != nil {
 			return err
 		}
@@ -402,6 +403,7 @@ var mountCmd = &cobra.Command{
 
 		log.Crit("Starting Blobfuse2 Mount : %s on [%s]", common.Blobfuse2Version, common.GetCurrentDistro())
 		log.Crit("Logging level set to : %s", logLevel.String())
+		log.Debug("Mount allowed on nonempty path : %v", options.NonEmpty)
 		pipeline, err = internal.NewPipeline(options.Components, !daemon.WasReborn())
 		if err != nil {
 			log.Err("mount : failed to initialize new pipeline [%v]", err)

cmd/mount_test.go

@@ -62,6 +62,7 @@ azstorage:
   mode: key
   endpoint: myEndpoint
   container: myContainer
+  max-retries: 1
 components:
   - libfuse
   - file_cache
@@ -73,20 +74,6 @@ health_monitor:
     - blobfuse_stats
 `
 
-var configMountLoopback string = `
-logging:
-  type: syslog
-default-working-dir: /tmp/blobfuse2
-components:
-  - libfuse
-  - loopbackfs
-libfuse:
-  attribute-expiration-sec: 120
-  entry-expiration-sec: 60
-loopbackfs:
-  path: /tmp/bfuseloopback
-`
-
 var configPriorityTest string = `
 logging:
   type: syslog
@@ -164,8 +151,9 @@ func (suite *mountTestSuite) TestMountDirNotEmpty() {
 	suite.assert.NotNil(err)
 	suite.assert.Contains(op, "mount directory is not empty")
 
-	op, err = executeCommandC(rootCmd, "mount", mntDir, fmt.Sprintf("--config-file=%s", confFileMntTest), "-o", "nonempty", "--foreground")
+	op, err = executeCommandC(rootCmd, "mount", mntDir, fmt.Sprintf("--config-file=%s", confFileMntTest), "-o", "nonempty")
 	suite.assert.NotNil(err)
+	suite.assert.Contains(op, "failed to initialize new pipeline")
 }
 
 // mount failure test where the mount path is not provided

component/libfuse/libfuse_handler.go

@@ -110,7 +110,6 @@ func (lf *Libfuse) convertConfig() *C.fuse_options_t {
 	fuse_opts.allow_other = C.bool(lf.allowOther)
 	fuse_opts.allow_root = C.bool(lf.allowRoot)
 	fuse_opts.trace_enable = C.bool(lf.traceEnable)
-	fuse_opts.non_empty = C.bool(lf.nonEmptyMount)
 	fuse_opts.umask = C.int(lf.umask)
 
 	return fuse_opts
@@ -210,10 +209,6 @@ func populateFuseArgs(opts *C.fuse_options_t, args *C.fuse_args_t) (*C.fuse_opti
 		options += ",allow_root"
 	}
 
-	if opts.non_empty {
-		options += ",nonempty"
-	}
-
 	if opts.readonly {
 		options += ",ro"
 	}

setup/baseConfig.yaml

@@ -32,7 +32,7 @@ foreground: true|false <run blobfuse2 in foreground or background>
 # Common configurations
 read-only: true|false <mount in read only mode - used for Streaming and FUSE>
 allow-other: true|false <allow other users to access the mounted directory - used for FUSE and File Cache>
-nonempty: true|false <allow mounting on non-empty directory - used for FUSE>
+nonempty: true|false <allow mounting on non-empty directory>
 
 # Dynamic profiler related configuration. This helps to root-cause high memory/cpu usage related issues.
 dynamic-profile: true|false <allows to turn on dynamic profiler for cpu/memory usage monitoring. Only for debugging, shall not be used in production>

test/mount_test/mount_test.go

@@ -140,7 +140,7 @@ func (suite *mountSuite) TestMountDirNotExists() {
 }
 
 // mount failure test where the mount directory is not empty
-func (suite *mountSuite) TestMountDirNotEmpty() {
+func (suite *mountSuite) TestMountDirNotEmptyFailure() {
 	tempDir := filepath.Join(mntDir, "tempdir")
 	_ = os.Mkdir(tempDir, 0777)
 	mountCmd := exec.Command(blobfuseBinary, "mount", mntDir, "--config-file="+configFile)
@@ -162,6 +162,32 @@ func (suite *mountSuite) TestMountDirNotEmpty() {
 	blobfuseUnmount(suite, "Nothing to unmount")
 }
 
+// mount non-empty directory using nonempty flag
+func (suite *mountSuite) TestMountDirNotEmptySuccess() {
+	tempDir := filepath.Join(mntDir, "tempdir")
+	_ = os.Mkdir(tempDir, 0777)
+
+	mountCmd := exec.Command(blobfuseBinary, "mount", mntDir, "--config-file="+configFile, "-o", "nonempty")
+	cliOut, err := mountCmd.Output()
+	suite.Equal(0, len(cliOut))
+	suite.Equal(nil, err)
+
+	// wait for mount
+	time.Sleep(10 * time.Second)
+
+	// validate mount
+	cliOut = listBlobfuseMounts(suite)
+	suite.NotEqual(0, len(cliOut))
+	suite.Contains(string(cliOut), mntDir)
+
+	remountCheck(suite)
+
+	// unmount
+	blobfuseUnmount(suite, mntDir)
+
+	os.RemoveAll(tempDir)
+}
+
 // mount failure test where the mount path is not provided
 func (suite *mountSuite) TestMountPathNotProvided() {
 	mountCmd := exec.Command(blobfuseBinary, "mount", "", "--config-file="+configFile)