vfs: add ECLOSED and tidy errors

cmd/cmount/fs.go

@@ -515,10 +515,14 @@ func translateError(err error) (errc int) {
 		return 0
 	case vfs.ENOENT:
 		return -fuse.ENOENT
-	case vfs.ENOTEMPTY:
-		return -fuse.ENOTEMPTY
 	case vfs.EEXIST:
 		return -fuse.EEXIST
+	case vfs.EPERM:
+		return -fuse.EPERM
+	case vfs.ECLOSED:
+		return -fuse.EBADF
+	case vfs.ENOTEMPTY:
+		return -fuse.ENOTEMPTY
 	case vfs.ESPIPE:
 		return -fuse.ESPIPE
 	case vfs.EBADF:
@@ -527,8 +531,6 @@ func translateError(err error) (errc int) {
 		return -fuse.EROFS
 	case vfs.ENOSYS:
 		return -fuse.ENOSYS
-	case vfs.EPERM:
-		return -fuse.EPERM
 	}
 	fs.Errorf(nil, "IO error: %v", err)
 	return -fuse.EIO

cmd/mount/fs.go

@@ -74,10 +74,14 @@ func translateError(err error) error {
 		return nil
 	case vfs.ENOENT:
 		return fuse.ENOENT
-	case vfs.ENOTEMPTY:
-		return fuse.Errno(syscall.ENOTEMPTY)
 	case vfs.EEXIST:
 		return fuse.EEXIST
+	case vfs.EPERM:
+		return fuse.EPERM
+	case vfs.ECLOSED:
+		return fuse.Errno(syscall.EBADF)
+	case vfs.ENOTEMPTY:
+		return fuse.Errno(syscall.ENOTEMPTY)
 	case vfs.ESPIPE:
 		return fuse.Errno(syscall.ESPIPE)
 	case vfs.EBADF:
@@ -86,8 +90,6 @@ func translateError(err error) error {
 		return fuse.Errno(syscall.EROFS)
 	case vfs.ENOSYS:
 		return fuse.ENOSYS
-	case vfs.EPERM:
-		return fuse.EPERM
 	}
 	return err
 }

vfs/errors.go

@@ -7,7 +7,7 @@ import (
 	"os"
 )
 
-// Error describes low level errors in a cross platform way
+// Error describes low level errors in a cross platform way.
 type Error byte
 
 // NB if changing errors translateError in cmd/mount/fs.go, cmd/cmount/fs.go
@@ -27,6 +27,7 @@ var (
 	ENOENT = os.ErrNotExist
 	EEXIST = os.ErrExist
 	EPERM  = os.ErrPermission
+	// ECLOSED see errors_{old,new}.go
 )
 
 var errorNames = []string{

vfs/errors_new.go

@@ -0,0 +1,10 @@
+// Errors for go1.8+
+
+//+build go1.8
+
+package vfs
+
+import "os"
+
+// ECLOSED is returned when a handle is closed twice
+var ECLOSED = os.ErrClosed

vfs/errors_old.go

@@ -0,0 +1,10 @@
+// Errors for pre go1.8
+
+//+build !go1.8
+
+package vfs
+
+import "errors"
+
+// ECLOSED is returned when a handle is closed twice
+var ECLOSED = errors.New("file already closed")

vfs/read.go

@@ -175,7 +175,7 @@ func (fh *ReadFileHandle) ReadAt(p []byte, off int64) (n int, err error) {
 	// fs.Debugf(fh.o, "ReadFileHandle.Read size %d offset %d", reqSize, off)
 	if fh.closed {
 		fs.Errorf(fh.o, "ReadFileHandle.Read error: %v", EBADF)
-		return 0, EBADF
+		return 0, ECLOSED
 	}
 	doSeek := off != fh.offset
 	if doSeek && fh.noSeek {
@@ -305,7 +305,7 @@ func (fh *ReadFileHandle) Read(p []byte) (n int, err error) {
 // Must be called with fh.mu held
 func (fh *ReadFileHandle) close() error {
 	if fh.closed {
-		return EBADF
+		return ECLOSED
 	}
 	fh.closed = true
 

vfs/read_test.go

@@ -76,7 +76,7 @@ func TestReadFileHandleMethods(t *testing.T) {
 	assert.True(t, fh.closed)
 
 	// Close again
-	assert.Equal(t, EBADF, fh.Close())
+	assert.Equal(t, ECLOSED, fh.Close())
 }
 
 func TestReadFileHandleSeek(t *testing.T) {
@@ -177,7 +177,7 @@ func TestReadFileHandleReadAt(t *testing.T) {
 	// check reading on closed file
 	fh.noSeek = true
 	n, err = fh.ReadAt(buf, 100)
-	assert.Equal(t, EBADF, err)
+	assert.Equal(t, ECLOSED, err)
 }
 
 func TestReadFileHandleFlush(t *testing.T) {

vfs/vfs.go

@@ -11,6 +11,11 @@
 // use paths with slashes in.
 //
 // It also includes directory caching
+//
+// The vfs package returns Error values to signal precisely which
+// error conditions have ocurred.  It may also return general errors
+// it receives.  It tries to use os Error values (eg os.ErrExist)
+// where possible.
 package vfs
 
 import (

vfs/write.go

@@ -88,7 +88,7 @@ func (fh *WriteFileHandle) WriteAt(p []byte, off int64) (n int, err error) {
 	defer fh.mu.Unlock()
 	if fh.closed {
 		fs.Errorf(fh.remote, "WriteFileHandle.Write error: %v", EBADF)
-		return 0, EBADF
+		return 0, ECLOSED
 	}
 	if fh.offset != off {
 		fs.Errorf(fh.remote, "WriteFileHandle.Write can't seek in file")
@@ -129,7 +129,7 @@ func (fh *WriteFileHandle) Offset() (offset int64) {
 // Must be called with fh.mu held
 func (fh *WriteFileHandle) close() error {
 	if fh.closed {
-		return EBADF
+		return ECLOSED
 	}
 	fh.closed = true
 	fh.file.addWriters(-1)

vfs/write_test.go

@@ -61,7 +61,7 @@ func TestWriteFileHandleMethods(t *testing.T) {
 
 	// Check double close
 	err = fh.Close()
-	assert.Equal(t, EBADF, err)
+	assert.Equal(t, ECLOSED, err)
 
 	// check vfs
 	root, err := vfs.Root()
@@ -105,7 +105,7 @@ func TestWriteFileHandleWriteAt(t *testing.T) {
 
 	// Check can't write on closed handle
 	n, err = fh.WriteAt([]byte("hello"), 0)
-	assert.Equal(t, EBADF, err)
+	assert.Equal(t, ECLOSED, err)
 	assert.Equal(t, 0, n)
 
 	// check vfs