Merge commit from fork

Author: robertdrakedennis

server/filesystem/quota_file.go

@@ -24,12 +24,15 @@ func (f *quotaFile) Write(p []byte) (int, error) {
 		return f.File.Write(p)
 	}
 
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
 	off, err := f.File.Seek(0, io.SeekCurrent)
 	if err != nil {
 		return 0, err
 	}
 
-	return f.writeAt(p, off, func() (int, error) {
+	return f.writeAtLocked(p, off, func() (int, error) {
 		return f.File.Write(p)
 	})
 }
@@ -39,15 +42,15 @@ func (f *quotaFile) WriteAt(p []byte, off int64) (int, error) {
 		return f.File.WriteAt(p, off)
 	}
 
-	return f.writeAt(p, off, func() (int, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
+	return f.writeAtLocked(p, off, func() (int, error) {
 		return f.File.WriteAt(p, off)
 	})
 }
 
-func (f *quotaFile) writeAt(p []byte, off int64, write func() (int, error)) (int, error) {
-	f.mu.Lock()
-	defer f.mu.Unlock()
-
+func (f *quotaFile) writeAtLocked(p []byte, off int64, write func() (int, error)) (int, error) {
 	previousSize := f.size
 	if growth := off + int64(len(p)) - previousSize; growth > 0 {
 		if err := f.fs.reserveDisk(growth); err != nil {

sftp/utils.go

@@ -3,6 +3,7 @@ package sftp
 import (
 	"io"
 	"os"
+	"reflect"
 )
 
 const (
@@ -30,6 +31,23 @@ func (l ListerAt) ListAt(f []os.FileInfo, offset int64) (int, error) {
 
 type fxErr uint32
 
+func (e fxErr) As(target interface{}) bool {
+	// pkg/sftp checks errors against its private fxerr type before writing status packets.
+	v := reflect.ValueOf(target)
+	if v.Kind() != reflect.Ptr || v.IsNil() {
+		return false
+	}
+
+	elem := v.Elem()
+	t := elem.Type()
+	if elem.Kind() != reflect.Uint32 || t.PkgPath() != "github.com/pkg/sftp" || t.Name() != "fxerr" {
+		return false
+	}
+
+	elem.SetUint(uint64(e))
+	return true
+}
+
 func (e fxErr) Error() string {
 	switch e {
 	case ErrSSHQuotaExceeded: