commit 236e5e800e18a0c1720ec1044a74c2700107c60c
author Paul Lawrence <paullawrence@google.com> Tue Jun 25 14:44:33 2019 -0700
committer Paul Lawrence <paullawrence@google.com> Wed Jun 26 15:19:24 2019 -0700
tree 311f14a8aed9ca5ab9be6351875f895ada2c122f
parent 2ebb5c5b9679a8ce96927aac55d621884834d173

Make ext4 userdata checkpoints work with metadata encryption

When both ext4 user data checkpoints and metadata encryption are
enabled, we are creating two stacked dm devices. This had not been
properly thought through or debugged.

Test: Enable metadata encryption on taimen (add
keydirectory=/metadata/vold/metadata_encryption to flags for userdata in
fstab.hardware)
    Unfortunately metadata is not wiped by fastboot -w, so it is
    necessary to rm metadata/vold -rf whenever you wipe data.
    fastboot flashall -w works
    fastboot reboot -w works
    A normal boot works
    Disable checkpoint commits with
    setprop persist.vold.dont_commit_checkpoint 1
    vdc checkpoint startCheckpoint 10
    adb reboot
    wait for device to fully boot then
    adb reboot
    Wait for device to fully boot then
    adb logcat -d | grep Checkpoint shows the rollback in the logs

    This tests encryption on top of checkpoints with commit, encryption
    without checkpoints, and rollback, which seems to be the key cases.

Bug: 135905679
Change-Id: I8365a40298b752af4bb10d00d9ff58ce04beab1f

Checkpoint.cpp

diff --git a/Checkpoint.cpp b/Checkpoint.cpp
index 56ec782..616365f 100644
--- a/Checkpoint.cpp
+++ b/Checkpoint.cpp
@@ -72,14 +72,11 @@
 }
 
 bool setBowState(std::string const& block_device, std::string const& state) {
-    if (block_device.substr(0, 5) != "/dev/") {
-        LOG(ERROR) << "Expected block device, got " << block_device;
-        return false;
-    }
+    std::string bow_device = fs_mgr_find_bow_device(block_device);
+    if (bow_device.empty()) return false;
 
-    std::string state_filename = std::string("/sys/") + block_device.substr(5) + "/bow/state";
-    if (!android::base::WriteStringToFile(state, state_filename)) {
-        PLOG(ERROR) << "Failed to write to file " << state_filename;
+    if (!android::base::WriteStringToFile(state, bow_device + "/bow/state")) {
+        PLOG(ERROR) << "Failed to write to file " << bow_device + "/bow/state";
         return false;
     }
 
@@ -287,7 +284,6 @@
 
 static void cp_healthDaemon(std::string mnt_pnt, std::string blk_device, bool is_fs_cp) {
     struct statvfs data;
-    uint64_t free_bytes = 0;
     uint32_t msleeptime = GetUintProperty(kSleepTimeProp, msleeptime_default, max_msleeptime);
     uint64_t min_free_bytes =
         GetUintProperty(kMinFreeBytesProp, min_free_bytes_default, (uint64_t)-1);
@@ -298,16 +294,17 @@
     msleeptime %= 1000;
     req.tv_nsec = msleeptime * 1000000;
     while (isCheckpointing) {
+        uint64_t free_bytes = 0;
         if (is_fs_cp) {
             statvfs(mnt_pnt.c_str(), &data);
             free_bytes = data.f_bavail * data.f_frsize;
         } else {
-            int ret;
-            std::string size_filename = std::string("/sys/") + blk_device.substr(5) + "/bow/free";
-            std::string content;
-            ret = android::base::ReadFileToString(size_filename, &content);
-            if (ret) {
-                free_bytes = std::strtoul(content.c_str(), NULL, 10);
+            std::string bow_device = fs_mgr_find_bow_device(blk_device);
+            if (!bow_device.empty()) {
+                std::string content;
+                if (android::base::ReadFileToString(bow_device + "/bow/free", &content)) {
+                    free_bytes = std::strtoul(content.c_str(), NULL, 10);
+                }
             }
         }
         if (free_bytes < min_free_bytes) {