Report physical blocks used

Tools like du and ls -l use this value to calculate the space used.
Force block size to 512 bytes for simplicity and compatibility with
Mac OS X which uses an older FUSE.

conversions.go

@@ -633,6 +633,8 @@ func convertAttributes(
 	out.Nlink = in.Nlink
 	out.Uid = in.Uid
 	out.Gid = in.Gid
+	// round up to the nearest 512 boundary
+	out.Blocks = (in.Size + 512 - 1) / 512
 
 	// Set the mode.
 	out.Mode = uint32(in.Mode) & 0777

samples/statfs/statfs.go

@@ -40,6 +40,9 @@ type FS interface {
 	// Set the canned response to be used for future statfs ops.
 	SetStatFSResponse(r fuseops.StatFSOp)
 
+	// Set the canned response to be used for future stat ops.
+	SetStatResponse(r fuseops.InodeAttributes)
+
 	// Return the size of the most recent write delivered by the kernel, or -1 if
 	// none.
 	MostRecentWriteSize() int
@@ -47,6 +50,9 @@ type FS interface {
 
 func New() (fs FS) {
 	fs = &statFS{
+		cannedStatResponse: fuseops.InodeAttributes{
+			Mode: 0666,
+		},
 		mostRecentWriteSize: -1,
 	}
 
@@ -59,8 +65,9 @@ type statFS struct {
 	fuseutil.NotImplementedFileSystem
 
 	mu                  sync.Mutex
-	cannedResponse      fuseops.StatFSOp // GUARDED_BY(mu)
+	cannedResponse      fuseops.StatFSOp        // GUARDED_BY(mu)
-	mostRecentWriteSize int              // GUARDED_BY(mu)
+	cannedStatResponse  fuseops.InodeAttributes // GUARDED_BY(mu)
+	mostRecentWriteSize int                     // GUARDED_BY(mu)
 }
 
 ////////////////////////////////////////////////////////////////////////
@@ -73,10 +80,8 @@ func dirAttrs() fuseops.InodeAttributes {
 	}
 }
 
-func fileAttrs() fuseops.InodeAttributes {
+func (fs *statFS) fileAttrs() fuseops.InodeAttributes {
-	return fuseops.InodeAttributes{
+	return fs.cannedStatResponse
-		Mode: 0666,
-	}
 }
 
 ////////////////////////////////////////////////////////////////////////
@@ -91,6 +96,14 @@ func (fs *statFS) SetStatFSResponse(r fuseops.StatFSOp) {
 	fs.cannedResponse = r
 }
 
+// LOCKS_EXCLUDED(fs.mu)
+func (fs *statFS) SetStatResponse(r fuseops.InodeAttributes) {
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+
+	fs.cannedStatResponse = r
+}
+
 // LOCKS_EXCLUDED(fs.mu)
 func (fs *statFS) MostRecentWriteSize() int {
 	fs.mu.Lock()
@@ -124,7 +137,7 @@ func (fs *statFS) LookUpInode(
 	}
 
 	op.Entry.Child = childInodeID
-	op.Entry.Attributes = fileAttrs()
+	op.Entry.Attributes = fs.fileAttrs()
 
 	return
 }
@@ -137,7 +150,7 @@ func (fs *statFS) GetInodeAttributes(
 		op.Attributes = dirAttrs()
 
 	case childInodeID:
-		op.Attributes = fileAttrs()
+		op.Attributes = fs.fileAttrs()
 
 	default:
 		err = fuse.ENOENT

samples/statfs/statfs_test.go

@@ -23,6 +23,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"strconv"
+	"syscall"
 	"testing"
 
 	"github.com/jacobsa/fuse/fuseops"
@@ -204,3 +205,24 @@ func (t *StatFSTest) WriteSize() {
 		AddFailure("Unhandled OS: %s", runtime.GOOS)
 	}
 }
+
+func (t *StatFSTest) StatBlocks() {
+	var err error
+	var stat syscall.Stat_t
+	const fileName = "foo"
+	const size = 1 << 22
+
+	err = ioutil.WriteFile(
+		path.Join(t.Dir, fileName),
+		bytes.Repeat([]byte{'x'}, size),
+		0400)
+	AssertEq(nil, err)
+
+	t.fs.SetStatResponse(fuseops.InodeAttributes{
+		Size: size,
+	})
+
+	err = syscall.Stat(path.Join(t.Dir, fileName), &stat)
+	AssertEq(nil, err)
+	ExpectEq(size/512, stat.Blocks)
+}