aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJakob Unterwurzacher2015-11-29 21:41:38 +0100
committerJakob Unterwurzacher2015-11-29 21:41:38 +0100
commit20b058a33335f48812864513cc13ea0a276aaaa3 (patch)
tree60baeaf7f3fe89e896a3a84a934079769d865215
parent1d0a442405e8fc7a0742a8f8db2ea0f874f750a5 (diff)
Add single-element cache for DirIV lookup
Another 3x performance boost for applications that walk the directory tree. Excerpt from performance.txt: VERSION UNTAR LS RM v0.4 48 1.5 5 v0.5-rc1 56 7 19 v0.5-rc1-1 54 4.1 9 v0.5-rc1-2 45 1.7 3.4 <---- THIS VERSION
-rw-r--r--cryptfs/cryptfs.go2
-rw-r--r--cryptfs/kdf.go6
-rw-r--r--cryptfs/names_diriv.go59
-rw-r--r--pathfs_frontend/fs.go13
-rw-r--r--performance.txt1
5 files changed, 74 insertions, 7 deletions
diff --git a/cryptfs/cryptfs.go b/cryptfs/cryptfs.go
index 63febc3..df04973 100644
--- a/cryptfs/cryptfs.go
+++ b/cryptfs/cryptfs.go
@@ -26,6 +26,8 @@ type CryptFS struct {
// Stores an all-zero block of size cipherBS
allZeroBlock []byte
plaintextNames bool
+ // DirIV cache for filename encryption
+ DirIVCacheEnc DirIVCache
}
func NewCryptFS(key []byte, useOpenssl bool, plaintextNames bool) *CryptFS {
diff --git a/cryptfs/kdf.go b/cryptfs/kdf.go
index 73be0bb..db08500 100644
--- a/cryptfs/kdf.go
+++ b/cryptfs/kdf.go
@@ -1,10 +1,10 @@
package cryptfs
import (
- "os"
- "math"
"fmt"
"golang.org/x/crypto/scrypt"
+ "math"
+ "os"
)
const (
@@ -50,5 +50,5 @@ func (s *scryptKdf) DeriveKey(pw string) []byte {
// LogN - N is saved as 2^LogN, but LogN is much easier to work with.
// This function gives you LogN = Log2(N).
func (s *scryptKdf) LogN() int {
- return int(math.Log2(float64(s.N))+0.5)
+ return int(math.Log2(float64(s.N)) + 0.5)
}
diff --git a/cryptfs/names_diriv.go b/cryptfs/names_diriv.go
index ae8545b..9012e48 100644
--- a/cryptfs/names_diriv.go
+++ b/cryptfs/names_diriv.go
@@ -5,8 +5,47 @@ import (
"io/ioutil"
"path/filepath"
"strings"
+ "sync"
)
+// A simple one-entry DirIV cache
+type DirIVCache struct {
+ // Invalidated?
+ cleared bool
+ // The DirIV
+ iv []byte
+ // Directory the DirIV belongs to
+ dir string
+ // Ecrypted version of "dir"
+ translatedDir string
+ // Synchronisation
+ lock sync.RWMutex
+}
+
+func (c *DirIVCache) lookup(dir string) (bool, []byte, string) {
+ c.lock.RLock()
+ defer c.lock.RUnlock()
+ if !c.cleared && c.dir == dir {
+ return true, c.iv, c.translatedDir
+ }
+ return false, nil, ""
+}
+
+func (c *DirIVCache) store(dir string, iv []byte, translatedDir string) {
+ c.lock.Lock()
+ defer c.lock.Unlock()
+ c.cleared = false
+ c.iv = iv
+ c.dir = dir
+ c.translatedDir = translatedDir
+}
+
+func (c *DirIVCache) Clear() {
+ c.lock.Lock()
+ defer c.lock.Unlock()
+ c.cleared = true
+}
+
// readDirIV - read the "gocryptfs.diriv" file from "dir" (absolute ciphertext path)
func (be *CryptFS) ReadDirIV(dir string) (iv []byte, err error) {
ivfile := filepath.Join(dir, DIRIV_FILENAME)
@@ -41,11 +80,23 @@ func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string) (string, e
if plainPath == "" {
return plainPath, nil
}
+ // Check if the DirIV is cached
+ parentDir := filepath.Dir(plainPath)
+ found, iv, cParentDir := be.DirIVCacheEnc.lookup(parentDir)
+ if found {
+ //fmt.Print("h")
+ baseName := filepath.Base(plainPath)
+ cBaseName := be.encryptName(baseName, iv)
+ cPath := cParentDir + "/" + cBaseName
+ return cPath, nil
+ }
+ // Walk the directory tree
var wd = rootDir
var encryptedNames []string
+ var err error
plainNames := strings.Split(plainPath, "/")
for _, plainName := range plainNames {
- iv, err := be.ReadDirIV(wd)
+ iv, err = be.ReadDirIV(wd)
if err != nil {
return "", err
}
@@ -53,7 +104,11 @@ func (be *CryptFS) EncryptPathDirIV(plainPath string, rootDir string) (string, e
encryptedNames = append(encryptedNames, encryptedName)
wd = filepath.Join(wd, encryptedName)
}
- return filepath.Join(encryptedNames...), nil
+ // Cache the final DirIV
+ cPath := strings.Join(encryptedNames, "/")
+ cParentDir = filepath.Dir(cPath)
+ be.DirIVCacheEnc.store(parentDir, iv, cParentDir)
+ return cPath, nil
}
// DecryptPathDirIV - encrypt path using CBC with DirIV
diff --git a/pathfs_frontend/fs.go b/pathfs_frontend/fs.go
index fe9a8b0..736e5dc 100644
--- a/pathfs_frontend/fs.go
+++ b/pathfs_frontend/fs.go
@@ -251,6 +251,8 @@ func (fs *FS) Mkdir(relPath string, mode uint32, context *fuse.Context) (code fu
if err != nil {
return fuse.ToStatus(err)
}
+ // The new directory may take the place of an older one that is still in the cache
+ fs.CryptFS.DirIVCacheEnc.Clear()
// Create directory
fs.dirIVLock.Lock()
defer fs.dirIVLock.Unlock()
@@ -315,7 +317,9 @@ func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) {
tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", st.Ino)
tmpDirivPath := filepath.Join(parentDir, tmpName)
cryptfs.Debug.Printf("Rmdir: Renaming %s to %s\n", cryptfs.DIRIV_FILENAME, tmpDirivPath)
- fs.dirIVLock.Lock() // directory will be in an inconsistent state after the rename
+ // The directory is in an inconsistent state between rename and rmdir. Protect against
+ // concurrent readers.
+ fs.dirIVLock.Lock()
defer fs.dirIVLock.Unlock()
err = os.Rename(dirivPath, tmpDirivPath)
if err != nil {
@@ -338,7 +342,8 @@ func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) {
if err != nil {
cryptfs.Warn.Printf("Rmdir: Could not clean up %s: %v\n", tmpName, err)
}
-
+ // The now-deleted directory may have been in the DirIV cache. Clear it.
+ fs.CryptFS.DirIVCacheEnc.Clear()
return fuse.OK
}
@@ -382,6 +387,10 @@ func (fs *FS) Rename(oldPath string, newPath string, context *fuse.Context) (cod
if err != nil {
return fuse.ToStatus(err)
}
+ // The Rename may cause a directory to take the place of another directory.
+ // That directory may still be in the DirIV cache, clear it.
+ fs.CryptFS.DirIVCacheEnc.Clear()
+
return fs.FileSystem.Rename(cOldPath, cNewPath, context)
}
diff --git a/performance.txt b/performance.txt
index 55678c3..2cd53a7 100644
--- a/performance.txt
+++ b/performance.txt
@@ -8,3 +8,4 @@ VERSION UNTAR LS RM
v0.4 48 1.5 5
v0.5-rc1 56 7 19
v0.5-rc1-1 54 4.1 9
+v0.5-rc1-2 45 1.7 3.4