Fsync directories after creating files

Bug: 112145641
Bug: 124279741
Bug: 120248692
Test: adb shell locksettings set-pin 1111 && \
    adb shell "echo b > /proc/sysrq-trigger"
Change-Id: I53d252942c21365983b4f8b6e0948b1864f195c1
Merged-In: I53d252942c21365983b4f8b6e0948b1864f195c1

Ext4Crypt.cpp

@@ -177,6 +177,7 @@ static void fixate_user_ce_key(const std::string& directory_path, const std::str
             PLOG(WARNING) << "Unable to rename " << to_fix << " to " << current_path;
         }
     }
+    android::vold::FsyncDirectory(directory_path);
 }
 
 static bool read_and_fixate_user_ce_key(userid_t user_id,
@@ -569,6 +570,7 @@ bool e4crypt_add_user_key_auth(userid_t user_id, int serial, const std::string&
     std::string ce_key_path;
     if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false;
     if (!android::vold::storeKeyAtomically(ce_key_path, user_key_temp, auth, ce_key)) return false;
+    if (!android::vold::FsyncDirectory(directory_path)) return false;
     return true;
 }
 

KeyStorage.cpp

@@ -480,6 +480,7 @@ bool storeKey(const std::string& dir, const KeyAuthentication& auth, const KeyBu
         if (!encryptWithoutKeymaster(appId, key, &encryptedKey)) return false;
     }
     if (!writeStringToFile(encryptedKey, dir + "/" + kFn_encrypted_key)) return false;
+    if (!FsyncDirectory(dir)) return false;
     return true;
 }
 

Utils.cpp

@@ -24,6 +24,7 @@
 #include <android-base/properties.h>
 #include <android-base/strings.h>
 #include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
 #include <cutils/fs.h>
 #include <logwrap/logwrap.h>
 #include <private/android_filesystem_config.h>
@@ -731,5 +732,23 @@ bool IsRunningInEmulator() {
     return android::base::GetBoolProperty("ro.kernel.qemu", false);
 }
 
+bool FsyncDirectory(const std::string& dirname) {
+    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dirname.c_str(), O_RDONLY | O_CLOEXEC)));
+    if (fd == -1) {
+        PLOG(ERROR) << "Failed to open " << dirname;
+        return false;
+    }
+    if (fsync(fd) == -1) {
+        if (errno == EROFS || errno == EINVAL) {
+            PLOG(WARNING) << "Skip fsync " << dirname
+                          << " on a file system does not support synchronization";
+        } else {
+            PLOG(ERROR) << "Failed to fsync " << dirname;
+            return false;
+        }
+    }
+    return true;
+}
+
 }  // namespace vold
 }  // namespace android

Utils.h

@@ -125,6 +125,8 @@ bool Readlinkat(int dirfd, const std::string& path, std::string* result);
 /* Checks if Android is running in QEMU */
 bool IsRunningInEmulator();
 
+bool FsyncDirectory(const std::string& dirname);
+
 }  // namespace vold
 }  // namespace android