[Bugfix]Fix userspace-reboot failure when backing_dev exists but zram not swapped on
'/sys/block/zram0/backing_dev' will exist even if zram is not swapped on in some devices. And there is no reason to ensure that zram is swapped on if '/sys/block/zram0/backing_dev' exists. So, if we want to kill backing_dev during userspace reboot, we should check if zram is swapped on first.
TEST: as follow
- adb root
- adb shell swapoff /dev/block/zram0
- adb shell echo 1 > /sys/block/zram0/reset
- adb shell setprop test.userspace.reboot.flag 1
- adb reboot userspace
- (wait reboot ending) adb shell getprop test.userspace.reboot.flag (1 will be show if successful)
Signed-off-by: luwei9 <luwei9@xiaomi.com>
Change-Id: Icca569cf8d64bc024b867dae2ab789fc9e76445a
diff --git a/init/reboot.cpp b/init/reboot.cpp
index d9acee5..ab0e48e 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -450,10 +450,22 @@
// zram is able to use backing device on top of a loopback device.
// In order to unmount /data successfully, we have to kill the loopback device first
-#define ZRAM_DEVICE "/dev/block/zram0"
-#define ZRAM_RESET "/sys/block/zram0/reset"
-#define ZRAM_BACK_DEV "/sys/block/zram0/backing_dev"
+#define ZRAM_DEVICE "/dev/block/zram0"
+#define ZRAM_RESET "/sys/block/zram0/reset"
+#define ZRAM_BACK_DEV "/sys/block/zram0/backing_dev"
+#define ZRAM_INITSTATE "/sys/block/zram0/initstate"
static Result<void> KillZramBackingDevice() {
+ std::string zram_initstate;
+ if (!android::base::ReadFileToString(ZRAM_INITSTATE, &zram_initstate)) {
+ return ErrnoError() << "Failed to read " << ZRAM_INITSTATE;
+ }
+
+ zram_initstate.erase(zram_initstate.length() - 1);
+ if (zram_initstate == "0") {
+ LOG(INFO) << "Zram has not been swapped on";
+ return {};
+ }
+
if (access(ZRAM_BACK_DEV, F_OK) != 0 && errno == ENOENT) {
LOG(INFO) << "No zram backing device configured";
return {};