drbd: make suspend_io() / resume_io() must be thread and recursion safe
Avoid to prematurely resume application IO: don't set/clear a single
bit, but inc/dec an atomic counter.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index a262653..df3d89d 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -500,7 +500,6 @@
MD_NO_FUA, /* Users wants us to not use FUA/FLUSH on meta data dev */
- SUSPEND_IO, /* suspend application io */
BITMAP_IO, /* suspend application io;
once no more io in flight, start bitmap io */
BITMAP_IO_QUEUED, /* Started bitmap IO */
@@ -880,6 +879,7 @@
atomic_t rs_pending_cnt; /* RS request/data packets on the wire */
atomic_t unacked_cnt; /* Need to send replies for */
atomic_t local_cnt; /* Waiting for local completion */
+ atomic_t suspend_cnt;
/* Interval tree of pending local requests */
struct rb_root read_requests;
@@ -2263,7 +2263,7 @@
if (drbd_suspended(device))
return false;
- if (test_bit(SUSPEND_IO, &device->flags))
+ if (atomic_read(&device->suspend_cnt))
return false;
/* to avoid potential deadlock or bitmap corruption,