commit 85e3d8cd50c540b1a4827bd179e3b8b609731e61
author Paul Lawrence <paullawrence@google.com> Tue Apr 26 12:50:53 2016 -0700
committer Paul Lawrence <paullawrence@google.com> Fri Apr 29 07:58:21 2016 -0700
tree d41b96ef4a69da16e7a5b2119711fa6b1e4afbc4
parent a54cd8739c8d313b66354f99ed9419ccc3f6be10

Drop caches after installing key policy to avoid cache clashes

Note that this is an ugly workaround for a kernel bug.

Bug: 28373400
Change-Id: Iec1ae53f4e18f06e41e8cf1fcc3ab03fc9848632

Ext4Crypt.cpp

diff --git a/Ext4Crypt.cpp b/Ext4Crypt.cpp
index 309a1f2..eaac26a 100644
--- a/Ext4Crypt.cpp
+++ b/Ext4Crypt.cpp
@@ -176,6 +176,14 @@
     }
     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;
 }