SquashFS | Fix some bugs (#289)

* squashfs: add support for Disk.CreateFilesystem API

Signed-off-by: Xynnn007 <[email protected]>

* filesystem: add Close() method for cleaning jobs

When building filesystems, we usually have some temp files or
directories. The `Close()` method will help to do clean jobs when we
destroy the FileSystem struct.

Fixes #288

Signed-off-by: Xynnn007 <[email protected]>

* squashfs: fix example disk block size

squashfs requires block size must be >= 4KB.

Signed-off-by: Xynnn007 <[email protected]>

---------

Signed-off-by: Xynnn007 <[email protected]>

Author: Xynnn007

disk/disk.go

@@ -177,7 +177,7 @@ func (d *Disk) CreateFilesystem(spec FilesystemSpec) (filesystem.FileSystem, err
 	case filesystem.TypeExt4:
 		return ext4.Create(d.Backend, size, start, d.LogicalBlocksize, nil)
 	case filesystem.TypeSquashfs:
-		return nil, filesystem.ErrReadonlyFilesystem
+		return squashfs.Create(d.Backend, size, start, d.LogicalBlocksize)
 	default:
 		return nil, errors.New("unknown filesystem type requested")
 	}

examples/iso_create.go

@@ -25,7 +25,14 @@ func CreateIso(diskImg string) {
 	fspec := disk.FilesystemSpec{Partition: 0, FSType: filesystem.TypeISO9660, VolumeLabel: "label"}
 	fs, err := mydisk.CreateFilesystem(fspec)
 	check(err)
+	defer func() {
+		if err := fs.Close(); err != nil {
+			check(err)
+		}
+	}()
+
 	rw, err := fs.OpenFile("demo.txt", os.O_CREATE|os.O_RDWR)
+	check(err)
 	content := []byte("demo")
 	_, err = rw.Write(content)
 	check(err)

examples/squashfs_create.go

@@ -16,13 +16,19 @@ func CreateSquashfs(diskImg string) {
 		log.Fatal("must have a valid path for diskImg")
 	}
 	var diskSize int64 = 10 * 1024 * 1024 // 10 MB
-	mydisk, err := diskfs.Create(diskImg, diskSize, diskfs.SectorSizeDefault)
+	mydisk, err := diskfs.Create(diskImg, diskSize, diskfs.SectorSize4k)
 	check(err)
 
 	fspec := disk.FilesystemSpec{Partition: 0, FSType: filesystem.TypeSquashfs, VolumeLabel: "label"}
 	fs, err := mydisk.CreateFilesystem(fspec)
 	check(err)
+	defer func() {
+		if err := fs.Close(); err != nil {
+			check(err)
+		}
+	}()
 	rw, err := fs.OpenFile("demo.txt", os.O_CREATE|os.O_RDWR)
+	check(err)
 	content := []byte("demo")
 	_, err = rw.Write(content)
 	check(err)

filesystem/ext4/ext4.go

@@ -693,6 +693,11 @@ func Read(b backend.Storage, size, start, sectorsize int64) (*FileSystem, error)
 // interface guard
 var _ filesystem.FileSystem = (*FileSystem)(nil)
 
+// Do cleaning job for ext4. Note that ext4 does not have side-effects so we do not do anything.
+func (fs *FileSystem) Close() error {
+	return nil
+}
+
 // Type returns the type code for the filesystem. Always returns filesystem.TypeExt4
 func (fs *FileSystem) Type() filesystem.Type {
 	return filesystem.TypeExt4

filesystem/fat32/fat32.go

@@ -489,6 +489,11 @@ func (fs *FileSystem) writeFat() error {
 // interface guard
 var _ filesystem.FileSystem = (*FileSystem)(nil)
 
+// Do cleaning job for fat32. Note that fat32 does not have side-effects so we do not do anything.
+func (fs *FileSystem) Close() error {
+	return nil
+}
+
 // Type returns the type code for the filesystem. Always returns filesystem.TypeFat32
 func (fs *FileSystem) Type() filesystem.Type {
 	return filesystem.TypeFat32

filesystem/filesystem.go

@@ -46,6 +46,8 @@ type FileSystem interface {
 	// SetLabel changes the label on the writable filesystem. Different file system may hav different
 	// length constraints.
 	SetLabel(label string) error
+	// Close will cleanup the temporary files created by the filesystem generation steps
+	Close() error
 }
 
 // Type represents the type of disk this is

filesystem/iso9660/iso9660.go

@@ -289,6 +289,14 @@ func Read(b backend.Storage, size, start, blocksize int64) (*FileSystem, error)
 // interface guard
 var _ filesystem.FileSystem = (*FileSystem)(nil)
 
+// Delete the temporary directory created during the iso9660 image creation
+func (fsm *FileSystem) Close() error {
+	if fsm.workspace != "" {
+		return os.RemoveAll(fsm.workspace)
+	}
+	return nil
+}
+
 // Type returns the type code for the filesystem. Always returns filesystem.TypeFat32
 func (fsm *FileSystem) Type() filesystem.Type {
 	return filesystem.TypeISO9660

filesystem/squashfs/squashfs.go

@@ -232,6 +232,14 @@ func Read(b backend.Storage, size, start, blocksize int64) (*FileSystem, error)
 // interface guard
 var _ filesystem.FileSystem = (*FileSystem)(nil)
 
+// Delete the temporary directory created during the SquashFS image creation
+func (fs *FileSystem) Close() error {
+	if fs.workspace != "" {
+		return os.RemoveAll(fs.workspace)
+	}
+	return nil
+}
+
 // Type returns the type code for the filesystem. Always returns filesystem.TypeFat32
 func (fs *FileSystem) Type() filesystem.Type {
 	return filesystem.TypeSquashfs