Merge pull request #1554 from restic/fix-988

fuse: Correct behavior for reading after EOF, add snapshot template string

changelog/0.8.2/pull-1554

@@ -0,0 +1,7 @@
+Enhancement: fuse/mount: Correctly handle EOF, add template option
+
+We've added the `--snapshot-template` string, which can be used to specify a
+template for a snapshot directory. In addition, accessing data after the end of
+a file via the fuse mount is now handled correctly.
+
+https://github.com/restic/restic/pull/1554

cmd/restic/cmd_mount.go

@@ -5,6 +5,8 @@ package main
 
 import (
 	"os"
+	"strings"
+	"time"
 
 	"github.com/spf13/cobra"
 
@@ -25,6 +27,21 @@ var cmdMount = &cobra.Command{
 	Long: `
 The "mount" command mounts the repository via fuse to a directory. This is a
 read-only mount.
+
+Snapshot Directories
+====================
+
+If you need a different template for all directories that contain snapshots,
+you can pass a template via --snapshot-template. Example without colons:
+
+    --snapshot-template "2006-01-02_15-04-05"
+
+You need to specify a sample format for exactly the following timestamp:
+
+    Mon Jan 2 15:04:05 -0700 MST 2006
+
+For details please see the documentation for time.Format() at:
+  https://godoc.org/time#Time.Format
 `,
 	DisableAutoGenTag: true,
 	RunE: func(cmd *cobra.Command, args []string) error {
@@ -40,6 +57,7 @@ type MountOptions struct {
 	Host             string
 	Tags             restic.TagLists
 	Paths            []string
+	SnapshotTemplate string
 }
 
 var mountOptions MountOptions
@@ -55,6 +73,8 @@ func init() {
 	mountFlags.StringVarP(&mountOptions.Host, "host", "H", "", `only consider snapshots for this host`)
 	mountFlags.Var(&mountOptions.Tags, "tag", "only consider snapshots which include this `taglist`")
 	mountFlags.StringArrayVar(&mountOptions.Paths, "path", nil, "only consider snapshots which include this (absolute) `path`")
+
+	mountFlags.StringVar(&mountOptions.SnapshotTemplate, "snapshot-template", time.RFC3339, "set `template` to use for snapshot dirs")
 }
 
 func mount(opts MountOptions, gopts GlobalOptions, mountpoint string) error {
@@ -112,6 +132,7 @@ func mount(opts MountOptions, gopts GlobalOptions, mountpoint string) error {
 		Host:             opts.Host,
 		Tags:             opts.Tags,
 		Paths:            opts.Paths,
+		SnapshotTemplate: opts.SnapshotTemplate,
 	}
 	root, err := fuse.NewRoot(gopts.ctx, repo, cfg)
 	if err != nil {
@@ -136,6 +157,14 @@ func umount(mountpoint string) error {
 }
 
 func runMount(opts MountOptions, gopts GlobalOptions, args []string) error {
+	if opts.SnapshotTemplate == "" {
+		return errors.Fatal("snapshot template string cannot be empty")
+	}
+
+	if strings.ContainsAny(opts.SnapshotTemplate, `\/`) {
+		return errors.Fatal("snapshot template string contains a slash (/) or backslash (\\) character")
+	}
+
 	if len(args) == 0 {
 		return errors.Fatal("wrong number of parameters")
 	}

cmd/restic/integration_fuse_test.go

@@ -55,7 +55,9 @@ func waitForMount(t testing.TB, dir string) {
 }
 
 func testRunMount(t testing.TB, gopts GlobalOptions, dir string) {
-	opts := MountOptions{}
+	opts := MountOptions{
+		SnapshotTemplate: time.RFC3339,
+	}
 	rtest.OK(t, runMount(opts, gopts, []string{dir}))
 }
 

internal/fuse/dir.go

@@ -182,7 +182,6 @@ func (d *dir) Lookup(ctx context.Context, name string) (fs.Node, error) {
 	node, ok := d.items[name]
 	if !ok {
 		debug.Log("  Lookup(%v) -> not found", name)
-		debug.Log("     items: %v\n", d.items)
 		return nil, fuse.ENOENT
 	}
 	switch node.Type {

internal/fuse/file.go

@@ -4,7 +4,6 @@
 package fuse
 
 import (
-	"github.com/restic/restic/internal/errors"
 	"github.com/restic/restic/internal/restic"
 
 	"github.com/restic/restic/internal/debug"
@@ -111,7 +110,10 @@ func (f *file) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadR
 	if uint64(offset) > f.node.Size {
 		debug.Log("Read(%v): offset is greater than file size: %v > %v",
 			f.node.Name, req.Offset, f.node.Size)
-		return errors.New("offset greater than files size")
+
+		// return no data
+		resp.Data = resp.Data[:0]
+		return nil
 	}
 
 	// handle special case: file is empty

internal/fuse/root.go

@@ -20,6 +20,7 @@ type Config struct {
 	Host             string
 	Tags             []restic.TagList
 	Paths            []string
+	SnapshotTemplate string
 }
 
 // Root is the root node of the fuse mount of a repository.

internal/fuse/snapshots_dir.go

@@ -26,6 +26,8 @@ type SnapshotsDir struct {
 	tag     string
 	host    string
 	snCount int
+
+	template string
 }
 
 // SnapshotsIDSDir is a fuse directory which contains snapshots named by ids.
@@ -118,6 +120,7 @@ func NewSnapshotsDir(root *Root, inode uint64, tag string, host string) *Snapsho
 		latest:   "",
 		tag:      tag,
 		host:     host,
+		template: root.cfg.SnapshotTemplate,
 	}
 
 	return d
@@ -239,7 +242,7 @@ func updateSnapshots(ctx context.Context, root *Root) {
 }
 
 // read snapshot timestamps from the current repository-state.
-func updateSnapshotNames(d *SnapshotsDir) {
+func updateSnapshotNames(d *SnapshotsDir, template string) {
 	if d.snCount != d.root.snCount {
 		d.snCount = d.root.snCount
 		var latestTime time.Time
@@ -248,7 +251,7 @@ func updateSnapshotNames(d *SnapshotsDir) {
 		for _, sn := range d.root.snapshots {
 			if d.tag == "" || isElem(d.tag, sn.Tags) {
 				if d.host == "" || d.host == sn.Hostname {
-					name := sn.Time.Format(time.RFC3339)
+					name := sn.Time.Format(template)
 					if d.latest == "" || !sn.Time.Before(latestTime) {
 						latestTime = sn.Time
 						d.latest = name
@@ -258,7 +261,7 @@ func updateSnapshotNames(d *SnapshotsDir) {
 							break
 						}
 
-						name = fmt.Sprintf("%s-%d", sn.Time.Format(time.RFC3339), i)
+						name = fmt.Sprintf("%s-%d", sn.Time.Format(template), i)
 					}
 
 					d.names[name] = sn
@@ -276,7 +279,7 @@ func (d *SnapshotsDir) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
 	updateSnapshots(ctx, d.root)
 
 	// update snapshot names
-	updateSnapshotNames(d)
+	updateSnapshotNames(d, d.root.cfg.SnapshotTemplate)
 
 	items := []fuse.Dirent{
 		{
@@ -450,7 +453,7 @@ func (d *SnapshotsDir) Lookup(ctx context.Context, name string) (fs.Node, error)
 		updateSnapshots(ctx, d.root)
 
 		// update snapshot names
-		updateSnapshotNames(d)
+		updateSnapshotNames(d, d.root.cfg.SnapshotTemplate)
 
 		sn, ok := d.names[name]
 		if ok {