Merge tag 'dm-3.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:
 "This pull request is later than I'd have liked because I was waiting
  for some performance data to help finally justify sending the
  long-standing dm-crypt cpu scalability improvements upstream.

  Unfortunately we came up short, so those dm-crypt changes will
  continue to wait, but it seems we're not far off.

   . Add dm_accept_partial_bio interface to DM core to allow DM targets
     to only process a portion of a bio, the remainder being sent in the
     next bio.  This enables the old dm snapshot-origin target to only
     split write bios on chunk boundaries, read bios are now sent to the
     origin device unchanged.

   . Add DM core support for disabling WRITE SAME if the underlying SCSI
     layer disables it due to command failure.

   . Reduce lock contention in DM's bio-prison.

   . A few small cleanups and fixes to dm-thin and dm-era"

* tag 'dm-3.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm thin: update discard_granularity to reflect the thin-pool blocksize
  dm bio prison: implement per bucket locking in the dm_bio_prison hash table
  dm: remove symbol export for dm_set_device_limits
  dm: disable WRITE SAME if it fails
  dm era: check for a non-NULL metadata object before closing it
  dm thin: return ENOSPC instead of EIO when error_if_no_space enabled
  dm thin: cleanup noflush_work to use a proper completion
  dm snapshot: do not split read bios sent to snapshot-origin target
  dm snapshot: allocate a per-target structure for snapshot-origin target
  dm: introduce dm_accept_partial_bio
  dm: change sector_count member in clone_info from sector_t to unsigned

1 files changed, 60 insertions, 33 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 242ac2ea5f29..fc9c848a60c9 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -310,13 +310,18 @@ static void cell_defer_no_holder_no_free(struct thin_c *tc,
 	wake_worker(pool);
 }
 
-static void cell_error(struct pool *pool,
-		       struct dm_bio_prison_cell *cell)
+static void cell_error_with_code(struct pool *pool,
+				 struct dm_bio_prison_cell *cell, int error_code)
 {
-	dm_cell_error(pool->prison, cell);
+	dm_cell_error(pool->prison, cell, error_code);
 	dm_bio_prison_free_cell(pool->prison, cell);
 }
 
+static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
+{
+	cell_error_with_code(pool, cell, -EIO);
+}
+
 /*----------------------------------------------------------------*/
 
 /*
@@ -1027,7 +1032,7 @@ static void retry_on_resume(struct bio *bio)
 	spin_unlock_irqrestore(&tc->lock, flags);
 }
 
-static bool should_error_unserviceable_bio(struct pool *pool)
+static int should_error_unserviceable_bio(struct pool *pool)
 {
 	enum pool_mode m = get_pool_mode(pool);
 
@@ -1035,25 +1040,27 @@ static bool should_error_unserviceable_bio(struct pool *pool)
 	case PM_WRITE:
 		/* Shouldn't get here */
 		DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
-		return true;
+		return -EIO;
 
 	case PM_OUT_OF_DATA_SPACE:
-		return pool->pf.error_if_no_space;
+		return pool->pf.error_if_no_space ? -ENOSPC : 0;
 
 	case PM_READ_ONLY:
 	case PM_FAIL:
-		return true;
+		return -EIO;
 	default:
 		/* Shouldn't get here */
 		DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
-		return true;
+		return -EIO;
 	}
 }
 
 static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
 {
-	if (should_error_unserviceable_bio(pool))
-		bio_io_error(bio);
+	int error = should_error_unserviceable_bio(pool);
+
+	if (error)
+		bio_endio(bio, error);
 	else
 		retry_on_resume(bio);
 }
@@ -1062,18 +1069,21 @@ static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *c
 {
 	struct bio *bio;
 	struct bio_list bios;
+	int error;
 
-	if (should_error_unserviceable_bio(pool)) {
-		cell_error(pool, cell);
+	error = should_error_unserviceable_bio(pool);
+	if (error) {
+		cell_error_with_code(pool, cell, error);
 		return;
 	}
 
 	bio_list_init(&bios);
 	cell_release(pool, cell, &bios);
 
-	if (should_error_unserviceable_bio(pool))
+	error = should_error_unserviceable_bio(pool);
+	if (error)
 		while ((bio = bio_list_pop(&bios)))
-			bio_io_error(bio);
+			bio_endio(bio, error);
 	else
 		while ((bio = bio_list_pop(&bios)))
 			retry_on_resume(bio);
@@ -1610,47 +1620,63 @@ static void do_no_space_timeout(struct work_struct *ws)
 
 /*----------------------------------------------------------------*/
 
-struct noflush_work {
+struct pool_work {
 	struct work_struct worker;
-	struct thin_c *tc;
+	struct completion complete;
+};
+
+static struct pool_work *to_pool_work(struct work_struct *ws)
+{
+	return container_of(ws, struct pool_work, worker);
+}
 
-	atomic_t complete;
-	wait_queue_head_t wait;
+static void pool_work_complete(struct pool_work *pw)
+{
+	complete(&pw->complete);
+}
+
+static void pool_work_wait(struct pool_work *pw, struct pool *pool,
+			   void (*fn)(struct work_struct *))
+{
+	INIT_WORK_ONSTACK(&pw->worker, fn);
+	init_completion(&pw->complete);
+	queue_work(pool->wq, &pw->worker);
+	wait_for_completion(&pw->complete);
+}
+
+/*----------------------------------------------------------------*/
+
+struct noflush_work {
+	struct pool_work pw;
+	struct thin_c *tc;
 };
 
-static void complete_noflush_work(struct noflush_work *w)
+static struct noflush_work *to_noflush(struct work_struct *ws)
 {
-	atomic_set(&w->complete, 1);
-	wake_up(&w->wait);
+	return container_of(to_pool_work(ws), struct noflush_work, pw);
 }
 
 static void do_noflush_start(struct work_struct *ws)
 {
-	struct noflush_work *w = container_of(ws, struct noflush_work, worker);
+	struct noflush_work *w = to_noflush(ws);
 	w->tc->requeue_mode = true;
 	requeue_io(w->tc);
-	complete_noflush_work(w);
+	pool_work_complete(&w->pw);
 }
 
 static void do_noflush_stop(struct work_struct *ws)
 {
-	struct noflush_work *w = container_of(ws, struct noflush_work, worker);
+	struct noflush_work *w = to_noflush(ws);
 	w->tc->requeue_mode = false;
-	complete_noflush_work(w);
+	pool_work_complete(&w->pw);
 }
 
 static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
 {
 	struct noflush_work w;
 
-	INIT_WORK_ONSTACK(&w.worker, fn);
 	w.tc = tc;
-	atomic_set(&w.complete, 0);
-	init_waitqueue_head(&w.wait);
-
-	queue_work(tc->pool->wq, &w.worker);
-
-	wait_event(w.wait, atomic_read(&w.complete));
+	pool_work_wait(&w.pw, tc->pool, fn);
 }
 
 /*----------------------------------------------------------------*/
@@ -3068,7 +3094,8 @@ static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
 	 */
 	if (pt->adjusted_pf.discard_passdown) {
 		data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
-		limits->discard_granularity = data_limits->discard_granularity;
+		limits->discard_granularity = max(data_limits->discard_granularity,
+						  pool->sectors_per_block << SECTOR_SHIFT);
 	} else
 		limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
 }