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[Bugfix]Fix userspace-reboot failure when backing_dev exists but zram not swapped on

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'/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
This commit is contained in:
luwei9 2021-04-14 14:34:59 +08:00 • committed by 陆伟
parent d8d9736573
commit 8a3653cfe2
1 changed files with 15 additions and 3 deletions
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18
init/reboot.cpp
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@ -450,10 +450,22 @@ static UmountStat TryUmountAndFsck(unsigned int cmd, bool run_fsck,
// 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 {};