7 files changed, 61 insertions, 36 deletions

diff --git a/drivers/md/persistent-data/dm-array.c b/drivers/md/persistent-data/dm-array.c
index 172147eb1d40..1d75b1dc1e2e 100644
--- a/drivers/md/persistent-data/dm-array.c
+++ b/drivers/md/persistent-data/dm-array.c
@@ -317,8 +317,16 @@ static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
 	 * The shadow op will often be a noop.  Only insert if it really
 	 * copied data.
 	 */
-	if (dm_block_location(*block) != b)
+	if (dm_block_location(*block) != b) {
+		/*
+		 * dm_tm_shadow_block will have already decremented the old
+		 * block, but it is still referenced by the btree.  We
+		 * increment to stop the insert decrementing it below zero
+		 * when overwriting the old value.
+		 */
+		dm_tm_inc(info->btree_info.tm, b);
 		r = insert_ablock(info, index, *block, root);
+	}
 
 	return r;
 }
@@ -509,15 +517,18 @@ static int grow_add_tail_block(struct resize *resize)
 static int grow_needs_more_blocks(struct resize *resize)
 {
 	int r;
+	unsigned old_nr_blocks = resize->old_nr_full_blocks;
 
 	if (resize->old_nr_entries_in_last_block > 0) {
+		old_nr_blocks++;
+
 		r = grow_extend_tail_block(resize, resize->max_entries);
 		if (r)
 			return r;
 	}
 
 	r = insert_full_ablocks(resize->info, resize->size_of_block,
-				resize->old_nr_full_blocks,
+				old_nr_blocks,
 				resize->new_nr_full_blocks,
 				resize->max_entries, resize->value,
 				&resize->root);
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index 81b513890e2b..6372d0bea532 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -595,25 +595,14 @@ int dm_bm_unlock(struct dm_block *b)
 }
 EXPORT_SYMBOL_GPL(dm_bm_unlock);
 
-int dm_bm_flush_and_unlock(struct dm_block_manager *bm,
-			   struct dm_block *superblock)
+int dm_bm_flush(struct dm_block_manager *bm)
 {
-	int r;
-
 	if (bm->read_only)
 		return -EPERM;
 
-	r = dm_bufio_write_dirty_buffers(bm->bufio);
-	if (unlikely(r)) {
-		dm_bm_unlock(superblock);
-		return r;
-	}
-
-	dm_bm_unlock(superblock);
-
 	return dm_bufio_write_dirty_buffers(bm->bufio);
 }
-EXPORT_SYMBOL_GPL(dm_bm_flush_and_unlock);
+EXPORT_SYMBOL_GPL(dm_bm_flush);
 
 void dm_bm_set_read_only(struct dm_block_manager *bm)
 {
diff --git a/drivers/md/persistent-data/dm-block-manager.h b/drivers/md/persistent-data/dm-block-manager.h
index be5bff61be28..f74c0462e5e4 100644
--- a/drivers/md/persistent-data/dm-block-manager.h
+++ b/drivers/md/persistent-data/dm-block-manager.h
@@ -105,8 +105,7 @@ int dm_bm_unlock(struct dm_block *b);
  *
  * This method always blocks.
  */
-int dm_bm_flush_and_unlock(struct dm_block_manager *bm,
-			   struct dm_block *superblock);
+int dm_bm_flush(struct dm_block_manager *bm);
 
 /*
  * Switches the bm to a read only mode.  Once read-only mode
diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c
index 3e7a88d99eb0..0d240373ffab 100644
--- a/drivers/md/persistent-data/dm-space-map-common.c
+++ b/drivers/md/persistent-data/dm-space-map-common.c
@@ -245,6 +245,10 @@ int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
 		return -EINVAL;
 	}
 
+	/*
+	 * We need to set this before the dm_tm_new_block() call below.
+	 */
+	ll->nr_blocks = nr_blocks;
 	for (i = old_blocks; i < blocks; i++) {
 		struct dm_block *b;
 		struct disk_index_entry idx;
@@ -252,6 +256,7 @@ int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
 		r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b);
 		if (r < 0)
 			return r;
+
 		idx.blocknr = cpu_to_le64(dm_block_location(b));
 
 		r = dm_tm_unlock(ll->tm, b);
@@ -266,7 +271,6 @@ int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
 			return r;
 	}
 
-	ll->nr_blocks = nr_blocks;
 	return 0;
 }
 
diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 1c959684caef..afb419e514bf 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -384,12 +384,16 @@ static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 
 	int r = sm_metadata_new_block_(sm, b);
-	if (r)
+	if (r) {
 		DMERR("unable to allocate new metadata block");
+		return r;
+	}
 
 	r = sm_metadata_get_nr_free(sm, &count);
-	if (r)
+	if (r) {
 		DMERR("couldn't get free block count");
+		return r;
+	}
 
 	check_threshold(&smm->threshold, count);
 
@@ -604,20 +608,38 @@ static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 	 * Flick into a mode where all blocks get allocated in the new area.
 	 */
 	smm->begin = old_len;
-	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
+	memcpy(sm, &bootstrap_ops, sizeof(*sm));
 
 	/*
 	 * Extend.
 	 */
 	r = sm_ll_extend(&smm->ll, extra_blocks);
+	if (r)
+		goto out;
 
 	/*
-	 * Switch back to normal behaviour.
+	 * We repeatedly increment then commit until the commit doesn't
+	 * allocate any new blocks.
 	 */
-	memcpy(&smm->sm, &ops, sizeof(smm->sm));
-	for (i = old_len; !r && i < smm->begin; i++)
-		r = sm_ll_inc(&smm->ll, i, &ev);
+	do {
+		for (i = old_len; !r && i < smm->begin; i++) {
+			r = sm_ll_inc(&smm->ll, i, &ev);
+			if (r)
+				goto out;
+		}
+		old_len = smm->begin;
+
+		r = sm_ll_commit(&smm->ll);
+		if (r)
+			goto out;
 
+	} while (old_len != smm->begin);
+
+out:
+	/*
+	 * Switch back to normal behaviour.
+	 */
+	memcpy(sm, &ops, sizeof(*sm));
 	return r;
 }
 
diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c
index 81da1a26042e..3bc30a0ae3d6 100644
--- a/drivers/md/persistent-data/dm-transaction-manager.c
+++ b/drivers/md/persistent-data/dm-transaction-manager.c
@@ -154,7 +154,7 @@ int dm_tm_pre_commit(struct dm_transaction_manager *tm)
 	if (r < 0)
 		return r;
 
-	return 0;
+	return dm_bm_flush(tm->bm);
 }
 EXPORT_SYMBOL_GPL(dm_tm_pre_commit);
 
@@ -164,8 +164,9 @@ int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root)
 		return -EWOULDBLOCK;
 
 	wipe_shadow_table(tm);
+	dm_bm_unlock(root);
 
-	return dm_bm_flush_and_unlock(tm->bm, root);
+	return dm_bm_flush(tm->bm);
 }
 EXPORT_SYMBOL_GPL(dm_tm_commit);
 
diff --git a/drivers/md/persistent-data/dm-transaction-manager.h b/drivers/md/persistent-data/dm-transaction-manager.h
index b5b139076ca5..2772ed2a781a 100644
--- a/drivers/md/persistent-data/dm-transaction-manager.h
+++ b/drivers/md/persistent-data/dm-transaction-manager.h
@@ -38,18 +38,17 @@ struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transac
 /*
  * We use a 2-phase commit here.
  *
- * i) In the first phase the block manager is told to start flushing, and
- * the changes to the space map are written to disk.  You should interrogate
- * your particular space map to get detail of its root node etc. to be
- * included in your superblock.
+ * i) Make all changes for the transaction *except* for the superblock.
+ * Then call dm_tm_pre_commit() to flush them to disk.
  *
- * ii) @root will be committed last.  You shouldn't use more than the
- * first 512 bytes of @root if you wish the transaction to survive a power
- * failure.  You *must* have a write lock held on @root for both stage (i)
- * and (ii).  The commit will drop the write lock.
+ * ii) Lock your superblock.  Update.  Then call dm_tm_commit() which will
+ * unlock the superblock and flush it.  No other blocks should be updated
+ * during this period.  Care should be taken to never unlock a partially
+ * updated superblock; perform any operations that could fail *before* you
+ * take the superblock lock.
  */
 int dm_tm_pre_commit(struct dm_transaction_manager *tm);
-int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root);
+int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *superblock);
 
 /*
  * These methods are the only way to get hold of a writeable block.