Merge "Drop caches after installing key policy to avoid cache clashes" into nyc-mr1-dev am: 235e78b9ae

am: 7b6ff76185

* commit '7b6ff7618562802fc8b1fd8abf5c3e6589216ceb':
  Drop caches after installing key policy to avoid cache clashes

Change-Id: Iacc5e9d73595b3bfd328e16f2b970b4e7f7b98bc

Ext4Crypt.cpp

@@ -176,6 +176,14 @@ static bool install_key(const std::string& key, std::string* raw_ref) {
     }
     LOG(DEBUG) << "Added key " << key_id << " (" << ref << ") to keyring " << device_keyring
                << " in process " << getpid();
+
+    // *TODO* Remove this code when kernel is fixed - see b/28373400
+    // Kernel preserves caches across a key insertion with ext4ice, which leads
+    // to contradictory dirents
+    if (!android::base::WriteStringToFile("3", "/proc/sys/vm/drop_caches")) {
+        PLOG(ERROR) << "Failed to drop_caches";
+    }
+
     return true;
 }