Downgrade "gocryptfs.diriv not found" warning if the directory was deleted

The directory may have been concurrently deleted or moved. Failure to
read the diriv is not an error in that case.

Downgrading the message to debug.

1 files changed, 18 insertions, 9 deletions

diff --git a/cryptfs/names_diriv.go b/cryptfs/names_diriv.go
index 2e2429e..9519ebc 100644
--- a/cryptfs/names_diriv.go
+++ b/cryptfs/names_diriv.go
@@ -1,6 +1,7 @@
 package cryptfs
 
 import (
+	"os"
 	"fmt"
 	"io/ioutil"
 	"path/filepath"
@@ -49,16 +50,24 @@ func (c *DirIVCache) Clear() {
 }
 
 // readDirIV - read the "gocryptfs.diriv" file from "dir" (absolute ciphertext path)
-func (be *CryptFS) ReadDirIV(dir string) (iv []byte, err error) {
+func (be *CryptFS) ReadDirIV(dir string) (iv []byte, readErr error) {
 	ivfile := filepath.Join(dir, DIRIV_FILENAME)
-	Debug.Printf("readDirIV: reading %s\n", ivfile)
-	iv, err = ioutil.ReadFile(ivfile)
-	if err != nil {
-		Warn.Printf("readDirIV: %v\n", err)
-		return nil, err
+	Debug.Printf("ReadDirIV: reading %s\n", ivfile)
+	iv, readErr = ioutil.ReadFile(ivfile)
+	if readErr != nil {
+		// The directory may have been concurrently deleted or moved. Failure to
+		// read the diriv is not an error in that case.
+		_, statErr := os.Stat(dir)
+		if os.IsNotExist(statErr) {
+			Debug.Printf("ReadDirIV: Dir %s was deleted under our feet", dir)
+		} else {
+			// This should not happen
+			Warn.Printf("ReadDirIV: Dir exists but diriv does not: %v\n", readErr)
+		}
+		return nil, readErr
 	}
 	if len(iv) != DIRIV_LEN {
-		return nil, fmt.Errorf("readDirIV: Invalid length %d\n", len(iv))
+		return nil, fmt.Errorf("ReadDirIV: Invalid length %d\n", len(iv))
 	}
 	return iv, nil
 }
@@ -73,7 +82,7 @@ func WriteDirIV(dir string) error {
 	return ioutil.WriteFile(file, iv, 0444)
 }
 
-// EncryptPathDirIV - encrypt path using CBC or EME with DirIV
+// EncryptPathDirIV - encrypt path using EME with DirIV
 func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string, eme bool) (cipherPath string, err error) {
 	// Empty string means root directory
 	if plainPath == "" {
@@ -109,7 +118,7 @@ func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string, eme bool)
 	return cipherPath, nil
 }
 
-// DecryptPathDirIV - encrypt path using CBC or EME with DirIV
+// DecryptPathDirIV - decrypt path using EME with DirIV
 func (be *CryptFS) DecryptPathDirIV(encryptedPath string, rootDir string, eme bool) (string, error) {
 	var wd = rootDir
 	var plainNames []string