bcache: fix uninterruptible sleep in writeback thread
There were two issues here:
- writeback thread did not start until the device first became dirty
- writeback thread used uninterruptible sleep once running
Without this patch I see kernel warnings printed and a load average of
1.52 after booting my test VM. With this patch the warnings are gone and
the load average is near 0.00 as expected.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 3b043a0..00cc425 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1042,6 +1042,9 @@
*/
atomic_set(&dc->count, 1);
+ if (bch_cached_dev_writeback_start(dc))
+ return -ENOMEM;
+
if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
bch_sectors_dirty_init(dc);
atomic_set(&dc->has_dirty, 1);