Support redaction and ContentResolver#open with passthroughHEADlineage-18.1

With FUSE passthrough enabled we can simplify the following policies:

1. Redaction: Always use passthrough for open(2) without redaction and
non-passthrough for open(2) with redaction. This works because
different VFS page caches are used for passthrough vs non-passthrough.

When passthrough is disabled, we still use the policy introduced in
I6eb1903ee22b8d713fe792ad8fef457a140e91f1

2. ContentResolver#open: All opens go through the FUSE filesystem,
this avoids the page cache inconsistency problems entirely! Hence, we
don't need any delicate file-locking algorithm to keep the cache
consistent.

Note that we still have to handle the dentry cache inconsistency
problems from unlink(2)/rename(2) within MediaProvider.

When passthrough is disabled, we still use the policy introduced in
I7726a75a51869c0e3ea3856103dd501b1aa19d14

Bug: 168023149
Test: atest ScopedStorageCoreHostTest#testVfsCacheConsistency
Change-Id: I8927cfb16f82578c9062036b3b46ad238e408ce6
Signed-off-by: alk3pInjection <webmaster@raspii.tech>

1 files changed, 4 insertions, 3 deletions

diff --git a/jni/node_test.cpp b/jni/node_test.cpp
index 357cea8e..0d7417f9 100644
--- a/jni/node_test.cpp
+++ b/jni/node_test.cpp
@@ -217,7 +217,8 @@ TEST_F(NodeTest, LookupAbsolutePath) {
 TEST_F(NodeTest, AddDestroyHandle) {
     unique_node_ptr node = CreateNode(nullptr, "/path");
 
-    handle* h = new handle(-1, new mediaprovider::fuse::RedactionInfo, true /* cached */);
+    handle* h = new handle(-1, new mediaprovider::fuse::RedactionInfo, true /* cached */,
+                           false /* passthrough */);
     node->AddHandle(h);
     ASSERT_TRUE(node->HasCachedHandle());
 
@@ -228,8 +229,8 @@ TEST_F(NodeTest, AddDestroyHandle) {
     // the node in question.
     EXPECT_DEATH(node->DestroyHandle(h), "");
     EXPECT_DEATH(node->DestroyHandle(nullptr), "");
-    std::unique_ptr<handle> h2(
-            new handle(-1, new mediaprovider::fuse::RedactionInfo, true /* cached */));
+    std::unique_ptr<handle> h2(new handle(-1, new mediaprovider::fuse::RedactionInfo,
+                                          true /* cached */, false /* passthrough */));
     EXPECT_DEATH(node->DestroyHandle(h2.get()), "");
 }