drbd: detach from frozen backing device

* drbd-8.3:
  documentation: Documented detach's --force and disk's --disk-timeout
  drbd: Implemented the disk-timeout option
  drbd: Force flag for the detach operation
  drbd: Allow new IOs while the local disk in in FAILED state
  drbd: Bitmap IO functions can not return prematurely if the disk breaks
  drbd: Added a kref to bm_aio_ctx
  drbd: Hold a reference to ldev while doing meta-data IO
  drbd: Keep a reference to the bio until the completion handler finished
  drbd: Implemented wait_until_done_or_disk_failure()
  drbd: Replaced md_io_mutex by an atomic: md_io_in_use
  drbd: moved md_io into mdev
  drbd: Immediately allow completion of IOs, that wait for IO completions on a failed disk
  drbd: Keep a reference to barrier acked requests

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 6035784f0de..4e582058a7c 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -780,8 +780,7 @@ struct drbd_backing_dev {
 };
 
 struct drbd_md_io {
-        struct drbd_conf *mdev;
-        struct completion event;
+        unsigned int done;
         int error;
 };
 
@@ -852,6 +851,7 @@ struct drbd_tconn {			/* is a resource from the config file */
         struct drbd_tl_epoch *newest_tle;
         struct drbd_tl_epoch *oldest_tle;
         struct list_head out_of_sequence_requests;
+        struct list_head barrier_acked_requests;
 
         struct crypto_hash *cram_hmac_tfm;
         struct crypto_hash *integrity_tfm;  /* checksums we compute, updates protected by tconn->data->mutex */
@@ -978,7 +978,8 @@ struct drbd_conf {
         atomic_t pp_in_use_by_net;      /* sendpage()d, still referenced by tcp */
         wait_queue_head_t ee_wait;
         struct page *md_io_page;        /* one page buffer for md_io */
-        struct mutex md_io_mutex;       /* protects the md_io_buffer */
+        struct drbd_md_io md_io;
+        atomic_t md_io_in_use;          /* protects the md_io, md_io_page and md_io_tmpp */
         spinlock_t al_lock;
         wait_queue_head_t al_wait;
         struct lru_cache *act_log;      /* activity log */
@@ -1424,9 +1425,12 @@ extern void resume_next_sg(struct drbd_conf *mdev);
 extern void suspend_other_sg(struct drbd_conf *mdev);
 extern int drbd_resync_finished(struct drbd_conf *mdev);
 /* maybe rather drbd_main.c ? */
+extern void *drbd_md_get_buffer(struct drbd_conf *mdev);
+extern void drbd_md_put_buffer(struct drbd_conf *mdev);
 extern int drbd_md_sync_page_io(struct drbd_conf *mdev,
                 struct drbd_backing_dev *bdev, sector_t sector, int rw);
 extern void drbd_ov_out_of_sync_found(struct drbd_conf *, sector_t, int);
+extern void wait_until_done_or_disk_failure(struct drbd_conf *mdev, unsigned int *done);
 extern void drbd_rs_controller_reset(struct drbd_conf *mdev);
 
 static inline void ov_out_of_sync_print(struct drbd_conf *mdev)
@@ -2151,12 +2155,12 @@ static inline int drbd_state_is_stable(struct drbd_conf *mdev)
         case D_OUTDATED:
         case D_CONSISTENT:
         case D_UP_TO_DATE:
+        case D_FAILED:
                 /* disk state is stable as well. */
                 break;
 
         /* no new io accepted during transitional states */
         case D_ATTACHING:
-        case D_FAILED:
         case D_NEGOTIATING:
         case D_UNKNOWN:
         case D_MASK: