1 files changed, 19 insertions, 6 deletions

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 87925e97e613..29e5c70e4e26 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -870,6 +870,11 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
                 retcode = ERR_DISK_CONFIGURED;
                 goto fail;
         }
+        /* It may just now have detached because of IO error.  Make sure
+         * drbd_ldev_destroy is done already, we may end up here very fast,
+         * e.g. if someone calls attach from the on-io-error handler,
+         * to realize a "hot spare" feature (not that I'd recommend that) */
+        wait_event(mdev->misc_wait, !atomic_read(&mdev->local_cnt));
 
         /* allocation not in the IO path, cqueue thread context */
         nbc = kzalloc(sizeof(struct drbd_backing_dev), GFP_KERNEL);
@@ -1098,9 +1103,9 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         /* Reset the "barriers don't work" bits here, then force meta data to
          * be written, to ensure we determine if barriers are supported. */
         if (nbc->dc.no_md_flush)
-                set_bit(MD_NO_BARRIER, &mdev->flags);
+                set_bit(MD_NO_FUA, &mdev->flags);
         else
-                clear_bit(MD_NO_BARRIER, &mdev->flags);
+                clear_bit(MD_NO_FUA, &mdev->flags);
 
         /* Point of no return reached.
          * Devices and memory are no longer released by error cleanup below.
@@ -1112,8 +1117,8 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         nbc = NULL;
         resync_lru = NULL;
 
-        mdev->write_ordering = WO_bio_barrier;
-        drbd_bump_write_ordering(mdev, WO_bio_barrier);
+        mdev->write_ordering = WO_bdev_flush;
+        drbd_bump_write_ordering(mdev, WO_bdev_flush);
 
         if (drbd_md_test_flag(mdev->ldev, MDF_CRASHED_PRIMARY))
                 set_bit(CRASHED_PRIMARY, &mdev->flags);
@@ -1262,7 +1267,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
  force_diskless_dec:
         put_ldev(mdev);
  force_diskless:
-        drbd_force_state(mdev, NS(disk, D_DISKLESS));
+        drbd_force_state(mdev, NS(disk, D_FAILED));
         drbd_md_sync(mdev);
  release_bdev2_fail:
         if (nbc)
@@ -1285,10 +1290,19 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         return 0;
 }
 
+/* Detaching the disk is a process in multiple stages.  First we need to lock
+ * out application IO, in-flight IO, IO stuck in drbd_al_begin_io.
+ * Then we transition to D_DISKLESS, and wait for put_ldev() to return all
+ * internal references as well.
+ * Only then we have finally detached. */
 static int drbd_nl_detach(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
                           struct drbd_nl_cfg_reply *reply)
 {
+        drbd_suspend_io(mdev); /* so no-one is stuck in drbd_al_begin_io */
         reply->ret_code = drbd_request_state(mdev, NS(disk, D_DISKLESS));
+        if (mdev->state.disk == D_DISKLESS)
+                wait_event(mdev->misc_wait, !atomic_read(&mdev->local_cnt));
+        drbd_resume_io(mdev);
         return 0;
 }
 
@@ -1953,7 +1967,6 @@ static int drbd_nl_resume_io(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         if (test_bit(NEW_CUR_UUID, &mdev->flags)) {
                 drbd_uuid_new_current(mdev);
                 clear_bit(NEW_CUR_UUID, &mdev->flags);
-                drbd_md_sync(mdev);
         }
         drbd_suspend_io(mdev);
         reply->ret_code = drbd_request_state(mdev, NS3(susp, 0, susp_nod, 0, susp_fen, 0));