/**
* Melt a frozen device.
*
* @wdev walb dev.
* @ctl ioctl data.
* RETURN:
* 0 in success, or -EFAULT.
*/
static int ioctl_wdev_melt(struct walb_dev *wdev, struct walb_ctl *ctl)
{
ASSERT(ctl->command == WALB_IOCTL_MELT);
LOGn("WALB_IOCTL_MELT\n");
cancel_melt_work(wdev);
if (melt_if_frozen(wdev, true)) {
return 0;
}
return -EFAULT;
}
/**
* Freeze a walb device.
* Currently write IOs will be frozen but read IOs will not.
*
* @wdev walb dev.
* @ctl ioctl data.
* RETURN:
* 0 in success, or -EFAULT.
*/
static int ioctl_wdev_freeze(struct walb_dev *wdev, struct walb_ctl *ctl)
{
u32 timeout_sec;
ASSERT(ctl->command == WALB_IOCTL_FREEZE);
LOGn("WALB_IOCTL_FREEZE\n");
/* Clip timeout value. */
timeout_sec = ctl->val_u32;
if (timeout_sec > 86400) {
timeout_sec = 86400;
LOGn("Freeze timeout has been cut to %"PRIu32" seconds.\n",
timeout_sec);
}
cancel_melt_work(wdev);
if (freeze_if_melted(wdev, timeout_sec)) {
return 0;
}
return -EFAULT;
}
/**
* Melt a device if frozen.
*
* RETURN:
* true in success, or false (due to race condition).
*/
bool melt_if_frozen(
struct walb_dev *wdev, bool restarts_checkpointing)
{
unsigned int minor;
ASSERT(wdev);
minor = MINOR(wdev->devt);
cancel_melt_work(wdev);
/* Melt the device if required. */
mutex_lock(&wdev->freeze_lock);
switch (wdev->freeze_state) {
case FRZ_MELTED:
/* Do nothing. */
LOGn("Already melted minor %u\n", minor);
break;
case FRZ_FREEZED:
/* Melt. */
LOGn("Melt walb device minor %u.\n", minor);
if (restarts_checkpointing) {
start_checkpointing(&wdev->cpd);
}
iocore_melt(wdev);
wdev->freeze_state = FRZ_MELTED;
break;
case FRZ_FREEZED_WITH_TIMEOUT:
/* Race condition. */
LOGe("Race condition occurred.\n");
mutex_unlock(&wdev->freeze_lock);
return false;
default:
BUG();
}
ASSERT(wdev->freeze_state == FRZ_MELTED);
mutex_unlock(&wdev->freeze_lock);
return true;
}
