Implement relatime behavior for performance

src/cryfs-cli/program_options/Parser.cpp

@@ -83,6 +83,9 @@ ProgramOptions Parser::parse(const vector<string> &supportedCiphers) const {
     if (vm.count("fuse-option")) {
         auto options = vm["fuse-option"].as<vector<string>>();
         for (const auto& option: options) {
+            if (option == "noatime" || option == "atime") {
+                LOG(WARN, "CryFS currently doesn't support noatime/atime flags. Using relatime behavior.");
+            }
             fuseOptions.push_back("-o");
             fuseOptions.push_back(option);
         }

src/cryfs/filesystem/CryDir.cpp

@@ -10,6 +10,7 @@
 #include "CryFile.h"
 #include "CryOpenFile.h"
 #include <cpp-utils/system/time.h>
+#include "fsblobstore/utils/TimestampUpdateBehavior.h"
 
 //TODO Get rid of this in favor of exception hierarchy
 using fspp::fuse::CHECK_RETVAL;
@@ -73,7 +74,7 @@ unique_ref<vector<fspp::Dir::Entry>> CryDir::children() {
   device()->callFsActionCallbacks();
   if (!isRootDir()) {
     //TODO Instead of doing nothing when we're the root directory, handle timestamps in the root dir correctly (and delete isRootDir() function)
-    parent()->updateAccessTimestampForChild(key());
+    parent()->updateAccessTimestampForChild(key(), fsblobstore::TimestampUpdateBehavior::RELATIME);
   }
   auto children = make_unique_ref<vector<fspp::Dir::Entry>>();
   children->push_back(fspp::Dir::Entry(fspp::Dir::EntryType::DIR, "."));

src/cryfs/filesystem/CryOpenFile.cpp

@@ -47,7 +47,7 @@ void CryOpenFile::truncate(off_t size) const {
 
 size_t CryOpenFile::read(void *buf, size_t count, off_t offset) const {
   _device->callFsActionCallbacks();
-  //_parent->updateAccessTimestampForChild(_fileBlob->key());
+  _parent->updateAccessTimestampForChild(_fileBlob->key(), fsblobstore::TimestampUpdateBehavior::RELATIME);
   return _fileBlob->read(buf, offset, count);
 }
 

src/cryfs/filesystem/CrySymlink.cpp

@@ -4,6 +4,7 @@
 #include "CryDevice.h"
 #include "CrySymlink.h"
 #include "parallelaccessfsblobstore/SymlinkBlobRef.h"
+#include "fsblobstore/utils/TimestampUpdateBehavior.h"
 
 //TODO Get rid of this in favor of exception hierarchy
 using fspp::fuse::CHECK_RETVAL;
@@ -46,7 +47,7 @@ fspp::Dir::EntryType CrySymlink::getType() const {
 
 bf::path CrySymlink::target() {
   device()->callFsActionCallbacks();
-  parent()->updateAccessTimestampForChild(key());
+  parent()->updateAccessTimestampForChild(key(), fsblobstore::TimestampUpdateBehavior::RELATIME);
   auto blob = LoadBlob();
   return blob->target();
 }

src/cryfs/filesystem/cachingfsblobstore/DirBlobRef.h

@@ -4,6 +4,7 @@
 
 #include "FsBlobRef.h"
 #include "../fsblobstore/DirBlob.h"
+#include "../fsblobstore/utils/TimestampUpdateBehavior.h"
 
 namespace cryfs {
 namespace cachingfsblobstore {
@@ -60,8 +61,8 @@ public:
         return _base->statChildWithSizeAlreadySet(key, result);
     }
 
-    void updateAccessTimestampForChild(const blockstore::Key &key) {
-        return _base->updateAccessTimestampForChild(key);
+    void updateAccessTimestampForChild(const blockstore::Key &key, fsblobstore::TimestampUpdateBehavior timestampUpdateBehavior) {
+        return _base->updateAccessTimestampForChild(key, timestampUpdateBehavior);
     }
 
     void updateModificationTimestampForChild(const blockstore::Key &key) {

src/cryfs/filesystem/fsblobstore/DirBlob.cpp

@@ -158,9 +158,9 @@ void DirBlob::statChildWithSizeAlreadySet(const Key &key, struct ::stat *result)
   result->st_blksize = _fsBlobStore->virtualBlocksizeBytes();
 }
 
-void DirBlob::updateAccessTimestampForChild(const Key &key) {
+void DirBlob::updateAccessTimestampForChild(const Key &key, TimestampUpdateBehavior timestampUpdateBehavior) {
   std::unique_lock<std::mutex> lock(_mutex);
-  _entries.updateAccessTimestampForChild(key);
+  _entries.updateAccessTimestampForChild(key, timestampUpdateBehavior);
   _changed = true;
 }
 

src/cryfs/filesystem/fsblobstore/DirBlob.h

@@ -60,7 +60,7 @@ namespace cryfs {
 
             void statChildWithSizeAlreadySet(const blockstore::Key &key, struct ::stat *result) const;
 
-            void updateAccessTimestampForChild(const blockstore::Key &key);
+            void updateAccessTimestampForChild(const blockstore::Key &key, TimestampUpdateBehavior timestampUpdateBehavior);
 
             void updateModificationTimestampForChild(const blockstore::Key &key);
 

src/cryfs/filesystem/fsblobstore/utils/DirEntry.h

@@ -7,8 +7,6 @@
 #include <cpp-utils/system/time.h>
 #include <sys/stat.h>
 
-// TODO Implement (and test) atime, noatime, strictatime, relatime mount options
-
 namespace cryfs {
     namespace fsblobstore {
 

src/cryfs/filesystem/fsblobstore/utils/DirEntryList.cpp

@@ -228,10 +228,18 @@ void DirEntryList::setAccessTimes(const blockstore::Key &key, timespec lastAcces
     found->setLastModificationTime(lastModificationTime);
 }
 
-void DirEntryList::updateAccessTimestampForChild(const blockstore::Key &key) {
+void DirEntryList::updateAccessTimestampForChild(const blockstore::Key &key, TimestampUpdateBehavior timestampUpdateBehavior) {
+    ASSERT(timestampUpdateBehavior == TimestampUpdateBehavior::RELATIME, "Currently only relatime supported");
     auto found = _findByKey(key);
-    // TODO Think about implementing relatime behavior. Currently, CryFS follows strictatime.
-    found->setLastAccessTime(cpputils::time::now());
+    const timespec lastAccessTime = found->lastAccessTime();
+    const timespec lastModificationTime = found->lastModificationTime();
+    const timespec now = cpputils::time::now();
+    const timespec yesterday {
+        .tv_sec = now.tv_sec - 60*60*24,
+        .tv_nsec = now.tv_nsec
+    };
+    if (lastAccessTime < lastModificationTime || lastAccessTime < yesterday)
+    found->setLastAccessTime(now);
 }
 
 void DirEntryList::updateModificationTimestampForChild(const blockstore::Key &key) {

src/cryfs/filesystem/fsblobstore/utils/DirEntryList.h

@@ -6,6 +6,7 @@
 #include "DirEntry.h"
 #include <vector>
 #include <string>
+#include "TimestampUpdateBehavior.h"
 
 //TODO Address elements by name instead of by key when accessing them. Who knows whether there is two hard links for the same blob.
 
@@ -39,7 +40,7 @@ namespace cryfs {
             void setMode(const blockstore::Key &key, mode_t mode);
             bool setUidGid(const blockstore::Key &key, uid_t uid, gid_t gid);
             void setAccessTimes(const blockstore::Key &key, timespec lastAccessTime, timespec lastModificationTime);
-            void updateAccessTimestampForChild(const blockstore::Key &key);
+            void updateAccessTimestampForChild(const blockstore::Key &key, TimestampUpdateBehavior timestampUpdateBehavior);
             void updateModificationTimestampForChild(const blockstore::Key &key);
 
         private:

src/cryfs/filesystem/fsblobstore/utils/TimestampUpdateBehavior.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#ifndef CRYFS_TIMESTAMPUPDATEBEHAVIOR_H
+#define CRYFS_TIMESTAMPUPDATEBEHAVIOR_H
+
+namespace cryfs {
+namespace fsblobstore {
+
+enum class TimestampUpdateBehavior : uint8_t {
+    // currently only relatime supported
+    RELATIME
+};
+
+}
+}
+
+#endif

src/cryfs/filesystem/parallelaccessfsblobstore/DirBlobRef.h

@@ -4,6 +4,7 @@
 
 #include "FsBlobRef.h"
 #include "../cachingfsblobstore/DirBlobRef.h"
+#include "../fsblobstore/utils/TimestampUpdateBehavior.h"
 
 namespace cryfs {
 namespace parallelaccessfsblobstore {
@@ -56,8 +57,8 @@ public:
         return _base->statChildWithSizeAlreadySet(key, result);
     }
 
-    void updateAccessTimestampForChild(const blockstore::Key &key) {
-        return _base->updateAccessTimestampForChild(key);
+    void updateAccessTimestampForChild(const blockstore::Key &key, fsblobstore::TimestampUpdateBehavior timestampUpdateBehavior) {
+        return _base->updateAccessTimestampForChild(key, timestampUpdateBehavior);
     }
 
     void updateModificationTimestampForChild(const blockstore::Key &key) {