commit 3f96053b3895f09b2887ee08ceda2bfcb857053d
author David Anderson <dvander@google.com> Wed May 03 11:26:13 2023 -0700
committer David Anderson <dvander@google.com> Wed May 03 19:07:50 2023 +0000
tree bee44b999292cde120c59e5696752dd90bb4e552
parent 5658f34653dcbe107670232402e38391f002a8bf

DO NOT MERGE: libsnapshot: Fix test failures on certain configurations.

Due to how CF is built and tested, VABC is enabled even when not
supported by the kernel. To work around this add some logic in
libsnapshot and the test harness to recognize this situation and
silently flip off the VABC flag.

This also fixes the -force_mode option to vts_libsnapshot_test, so that
it will skip tests that aren't supported by the device.

Bug: 264279496
Test: vts_libsnapshot_test on android13-gsi with 11-5.4 kernel
Change-Id: I9279d8d400cac5cd504a7ae91f254aae57fa856d

fs_mgr/libsnapshot/snapshot.cpp

diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 019b64a..cd4c560 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -3166,7 +3166,8 @@
               << " writer.GetCowVersion(): " << writer.GetCowVersion();
 
     bool use_compression = IsCompressionEnabled() && dap_metadata.vabc_enabled() &&
-                           !device_->IsRecovery() && cow_format_support;
+                           !device_->IsRecovery() && cow_format_support &&
+                           KernelSupportsCompressedSnapshots();
 
     std::string compression_algorithm;
     if (use_compression) {

fs_mgr/libsnapshot/snapshot_test.cpp

diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index e7ffb16..a741134 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -2760,7 +2760,7 @@
         return true;
     }
 
-    return IsUserspaceSnapshotsEnabled();
+    return IsUserspaceSnapshotsEnabled() && KernelSupportsCompressedSnapshots();
 }
 
 bool ShouldUseCompression() {
@@ -2770,7 +2770,7 @@
     if (FLAGS_force_config == "vabc") {
         return true;
     }
-    return IsCompressionEnabled();
+    return IsCompressionEnabled() && KernelSupportsCompressedSnapshots();
 }
 
 }  // namespace snapshot

fs_mgr/libsnapshot/utility.cpp

diff --git a/fs_mgr/libsnapshot/utility.cpp b/fs_mgr/libsnapshot/utility.cpp
index f01bec9..841acf4 100644
--- a/fs_mgr/libsnapshot/utility.cpp
+++ b/fs_mgr/libsnapshot/utility.cpp
@@ -26,7 +26,9 @@
 #include <android-base/properties.h>
 #include <android-base/strings.h>
 #include <fs_mgr/roots.h>
+#include <libdm/dm.h>
 
+using android::dm::DeviceMapper;
 using android::dm::kSectorSize;
 using android::fiemap::FiemapStatus;
 using android::fs_mgr::EnsurePathMounted;
@@ -208,5 +210,10 @@
     return android::base::GetBoolProperty("snapuserd.test.dm.snapshots", false);
 }
 
+bool KernelSupportsCompressedSnapshots() {
+    auto& dm = DeviceMapper::Instance();
+    return dm.GetTargetByName("user", nullptr);
+}
+
 }  // namespace snapshot
 }  // namespace android

fs_mgr/libsnapshot/utility.h

diff --git a/fs_mgr/libsnapshot/utility.h b/fs_mgr/libsnapshot/utility.h
index 0ef3234..0794154 100644
--- a/fs_mgr/libsnapshot/utility.h
+++ b/fs_mgr/libsnapshot/utility.h
@@ -129,6 +129,7 @@
 void AppendExtent(google::protobuf::RepeatedPtrField<chromeos_update_engine::Extent>* extents,
                   uint64_t start_block, uint64_t num_blocks);
 
+bool KernelSupportsCompressedSnapshots();
 bool IsCompressionEnabled();
 
 bool IsUserspaceSnapshotsEnabled();