contentenc: rename PlaintextRange and CiphertextRange

The name could be misunderstood and actually caused a bug:
doWrite used to always preallocate 4128 instead of the actual
data length.

internal/contentenc/content.go

@@ -40,10 +40,16 @@ func New(cc *cryptocore.CryptoCore, plainBS uint64) *ContentEnc {
 	}
 }
 
+// PlainBS returns the plaintext block size
 func (be *ContentEnc) PlainBS() uint64 {
 	return be.plainBS
 }
 
+// CipherBS returns the ciphertext block size
+func (be *ContentEnc) CipherBS() uint64 {
+	return be.cipherBS
+}
+
 // DecryptBlocks - Decrypt a number of blocks
 func (be *ContentEnc) DecryptBlocks(ciphertext []byte, firstBlockNo uint64, fileId []byte) ([]byte, error) {
 	cBuf := bytes.NewBuffer(ciphertext)

internal/contentenc/intrablock.go

@@ -16,16 +16,14 @@ func (ib *intraBlock) IsPartial() bool {
 	return false
 }
 
-// CiphertextRange - get byte range in ciphertext file corresponding to BlockNo
-// (complete block)
-func (ib *intraBlock) CiphertextRange() (offset uint64, length uint64) {
-	return ib.fs.BlockNoToCipherOff(ib.BlockNo), ib.fs.cipherBS
+// BlockCipherOff returns the ciphertext offset corresponding to BlockNo
+func (ib *intraBlock) BlockCipherOff() (offset uint64) {
+	return ib.fs.BlockNoToCipherOff(ib.BlockNo)
 }
 
-// PlaintextRange - get byte range in plaintext corresponding to BlockNo
-// (complete block)
-func (ib *intraBlock) PlaintextRange() (offset uint64, length uint64) {
-	return ib.fs.BlockNoToPlainOff(ib.BlockNo), ib.fs.plainBS
+// BlockPlainOff returns the plaintext offset corresponding to BlockNo
+func (ib *intraBlock) BlockPlainOff() (offset uint64) {
+	return ib.fs.BlockNoToPlainOff(ib.BlockNo)
 }
 
 // CropBlock - crop a potentially larger plaintext block down to the relevant part

internal/fusefrontend/file.go

@@ -244,7 +244,7 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
 		// Incomplete block -> Read-Modify-Write
 		if b.IsPartial() {
 			// Read
-			o, _ := b.PlaintextRange()
+			o := b.BlockPlainOff()
 			var oldData []byte
 			oldData, status = f.doRead(o, f.contentEnc.PlainBS())
 			if status != fuse.OK {
@@ -257,13 +257,13 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
 		}
 
 		// Encrypt
-		blockOffset, blockLen := b.CiphertextRange()
+		blockOffset := b.BlockCipherOff()
 		blockData = f.contentEnc.EncryptBlock(blockData, b.BlockNo, f.header.Id)
 		tlog.Debug.Printf("ino%d: Writing %d bytes to block #%d",
 			f.ino, uint64(len(blockData))-f.contentEnc.BlockOverhead(), b.BlockNo)
 
 		// Prevent partially written (=corrupt) blocks by preallocating the space beforehand
-		err := prealloc(int(f.fd.Fd()), int64(blockOffset), int64(blockLen))
+		err := prealloc(int(f.fd.Fd()), int64(blockOffset), int64(len(blockData)))
 		if err != nil {
 			tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %s", f.ino, f.intFd(), err.Error())
 			status = fuse.ToStatus(err)
@@ -410,12 +410,12 @@ func (f *file) Truncate(newSize uint64) fuse.Status {
 		}
 		lastBlock := addBlocks[len(addBlocks)-1]
 		if lastBlock.IsPartial() {
-			off, _ := lastBlock.PlaintextRange()
+			off := lastBlock.BlockPlainOff()
 			_, status := f.doWrite(make([]byte, lastBlock.Length), int64(off+lastBlock.Skip))
 			return status
 		} else {
-			off, length := lastBlock.CiphertextRange()
-			err = syscall.Ftruncate(f.intFd(), int64(off+length))
+			off := lastBlock.BlockCipherOff()
+			err = syscall.Ftruncate(f.intFd(), int64(off+f.contentEnc.CipherBS()))
 			if err != nil {
 				tlog.Warn.Printf("Truncate: grow Ftruncate returned error: %v", err)
 			}