func openTestCache(test *testing.T) (common.BlockDevice, *LRUCache) {
dev := testutils.NewTestDevice(test, 64, 100)
cache := NewLRUCache(4, 10, 16)
err := cache.MountDevice(0, dev, getDevInfo(64))
if err != nil {
testutils.ErrorHere(test, "Failed when mounting ramdisk device into cache: %s", err)
}
return dev, cache.(*LRUCache)
}
func TestGetConcurrency(test *testing.T) {
dev, cache := openTestCache(test)
bdev := testutils.NewBlockingDevice(testutils.NewTestDevice(test, 64, 100))
cache.MountDevice(1, bdev, getDevInfo(64))
// Test that reads from a normal device are not blocked by reads from a
// broken device.
wg := new(sync.WaitGroup)
wg.Add(2)
go func() {
// Do the read on the broken device
cb := cache.GetBlock(1, 0, common.FULL_DATA_BLOCK, common.NORMAL)
cache.PutBlock(cb, common.FULL_DATA_BLOCK)
wg.Done()
}()
go func() {
// Wait for the device to be blocked
<-bdev.HasBlocked
cb := cache.GetBlock(0, 0, common.FULL_DATA_BLOCK, common.NORMAL)
// Now unblock that device so we can shut down
bdev.Unblock <- true
cache.PutBlock(cb, common.FULL_DATA_BLOCK)
wg.Done()
}()
wg.Wait()
if err := cache.UnmountDevice(1); err != nil {
testutils.ErrorHere(test, "Failed when unmounting device: %s", err)
}
if err := bdev.Close(); err != nil {
testutils.ErrorHere(test, "Failed when closing device: %s", err)
}
closeTestCache(test, dev, cache)
}
// Test that blocks are cached. This test will deadlock if more than one block
// read is attempted from the underlying device.
func TestDoesCache(test *testing.T) {
// Open an always-broken device
dev := testutils.NewBlockingDevice(testutils.NewTestDevice(test, 64, 100))
cache := NewLRUCache(4, 10, 16)
err := cache.MountDevice(0, dev, getDevInfo(64))
if err != nil {
testutils.ErrorHere(test, "Failed when mounting ramdisk device into cache: %s", err)
}
wg := new(sync.WaitGroup)
wg.Add(2)
go func() {
// Allow a single block to be read
<-dev.HasBlocked
dev.Unblock <- true
wg.Done()
}()
go func() {
cb1 := cache.GetBlock(0, 5, common.FULL_DATA_BLOCK, common.NORMAL)
data, ok := cb1.Block.(common.FullDataBlock)
if !ok {
testutils.ErrorHere(test, "Did not get a FullDataBlock")
}
if data[0] != 5 {
testutils.ErrorHere(test, "Data in block did not match, expected %x, got %x", 5, data[0])
}
// this should be pulled from the cache, not from the device
cb2 := cache.GetBlock(0, 5, common.FULL_DATA_BLOCK, common.NORMAL)
if cb1 != cb2 {
testutils.ErrorHere(test, "Cache block mismatch, expected %p, got %p", cb1, cb2)
}
data, ok = cb2.Block.(common.FullDataBlock)
if !ok {
testutils.ErrorHere(test, "Did not get a FullDataBlock")
}
if data[0] != 5 {
testutils.ErrorHere(test, "Data in block did not match, expected %x, got %x", 5, data[0])
}
cache.PutBlock(cb1, common.FULL_DATA_BLOCK)
cache.PutBlock(cb2, common.FULL_DATA_BLOCK)
wg.Done()
}()
wg.Wait()
err = cache.UnmountDevice(0)
if err != nil {
testutils.ErrorHere(test, "Failed when unmounting ramdisk device: %s", err)
}
// if err = cache.Close(); err != nil {
// ErrorHere(test, "Failed when closing cache: %s", err)
// }
// if err = dev.Close(); err != nil {
// ErrorHere(test, "Failed when closing device: %s", err)
// }
}