lightnvm: pass flag on graceful teardown to targets

If the namespace is unregistered before the LightNVM target is removed
(e.g., on hot unplug) it is too late for the target to store any metadata
on the device - any attempt to write to the device will fail. In this
case, pass on a "gracefull teardown" flag to the target to let it know
when this happens.

In the case of pblk, we pad the open line (close all open chunks) to
improve data retention. In the event of an ungraceful shutdown, avoid
this part and just clean up.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 8 insertions, 6 deletions

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index 81c103b341bd..f47e95c0e5da 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -1118,23 +1118,25 @@ static void pblk_free(struct pblk *pblk)
         kfree(pblk);
 }
 
-static void pblk_tear_down(struct pblk *pblk)
+static void pblk_tear_down(struct pblk *pblk, bool graceful)
 {
-        pblk_pipeline_stop(pblk);
+        if (graceful)
+                __pblk_pipeline_flush(pblk);
+        __pblk_pipeline_stop(pblk);
         pblk_writer_stop(pblk);
         pblk_rb_sync_l2p(&pblk->rwb);
         pblk_rl_free(&pblk->rl);
 
-        pr_debug("pblk: consistent tear down\n");
+        pr_debug("pblk: consistent tear down (graceful:%d)\n", graceful);
 }
 
-static void pblk_exit(void *private)
+static void pblk_exit(void *private, bool graceful)
 {
         struct pblk *pblk = private;
 
         down_write(&pblk_lock);
-        pblk_gc_exit(pblk);
-        pblk_tear_down(pblk);
+        pblk_gc_exit(pblk, graceful);
+        pblk_tear_down(pblk, graceful);
 
 #ifdef CONFIG_NVM_DEBUG
         pr_info("pblk exit: L2P CRC: %x\n", pblk_l2p_crc(pblk));