diff --git a/filesystem.go b/filesystem.go
index cec9633..447b7ef 100644
--- a/filesystem.go
+++ b/filesystem.go
@@ -16,12 +16,13 @@ const writeFlag = os.O_RDWR | os.O_CREATE | os.O_TRUNC
 
 // WriteOnlyOnceFileSystem is a file write only wrapper for a webdav.FileSystem
 type WriteOnlyOnceFileSystem struct {
-	fs webdav.FileSystem
+	Filters []Filter
+	fs      webdav.FileSystem
 }
 
 // NewWriteOnlyOnceFileSystem returns a new WriteOnlyOnceFileSystem wrapping a webdav.FileSystem
 func NewWriteOnlyOnceFileSystem(fs webdav.FileSystem) *WriteOnlyOnceFileSystem {
-	return &WriteOnlyOnceFileSystem{fs}
+	return &WriteOnlyOnceFileSystem{fs: fs}
 }
 
 // Mkdir is not permitted
@@ -38,6 +39,12 @@ func (fs *WriteOnlyOnceFileSystem) OpenFile(ctx context.Context, name string, fl
 			return nil, ErrWonly
 		}
 	}
+	for _, filter := range fs.Filters {
+		err = filter.Filter(name)
+		if err != nil {
+			return nil, err
+		}
+	}
 	f, err := fs.fs.OpenFile(ctx, name, flag, perm)
 	if err != nil {
 		return nil, err
@@ -45,8 +52,15 @@ func (fs *WriteOnlyOnceFileSystem) OpenFile(ctx context.Context, name string, fl
 	return &File{f}, nil
 }
 
-// RemoveAll is not permitted
+// RemoveAll only permits deleting empty files
 func (fs *WriteOnlyOnceFileSystem) RemoveAll(ctx context.Context, name string) error {
+	fi, err := fs.fs.Stat(ctx, name)
+	if err != nil {
+		return err
+	}
+	if fi.Mode().IsRegular() && fi.Size() == 0 {
+		return fs.fs.RemoveAll(ctx, name)
+	}
 	return ErrWonly
 }
 
diff --git a/filter.go b/filter.go
new file mode 100644
index 0000000..7c6d442
--- /dev/null
+++ b/filter.go
@@ -0,0 +1,44 @@
+// Copyright (C) 2019 Marius Schellenberger
+
+package authdav
+
+import (
+	"errors"
+	"path/filepath"
+	"strings"
+)
+
+type Matcher func(path string) bool
+
+type Filter interface {
+	Filter(path string) error
+}
+
+var ErrMacOSFilter = errors.New("authdav: MacOS filter: access denied")
+
+type MacOSFilter struct {
+	match []Matcher
+}
+
+func NewMacOSFilter() *MacOSFilter {
+	return &MacOSFilter{
+		match: []Matcher{
+			func(p string) {
+				return p == ".DS_Store"
+			},
+			func(p string) {
+				return strings.HasPrefix(p, "._")
+			},
+		},
+	}
+}
+
+func (f *MacOSFilter) Filter(path string) error {
+	_, f := filepath.Split(path)
+	for _, m := range f.match {
+		if m(f) {
+			return ErrMacOSFilter
+		}
+	}
+	return nil
+}
diff --git a/go.mod b/go.mod
index ac73fd3..02cb02c 100644
--- a/go.mod
+++ b/go.mod
@@ -1 +1,5 @@
 module git.giftfish.de/ston1th/authdav
+
+go 1.12
+
+require golang.org/x/net v0.0.0-20190827160401-ba9fcec4b297
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..dc1e52d
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,5 @@
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190827160401-ba9fcec4b297 h1:k7pJ2yAPLPgbskkFdhRCsA77k2fySZ1zf2zCjvQCiIM=
+golang.org/x/net v0.0.0-20190827160401-ba9fcec4b297/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=