dm thin metadata: add format option to dm_pool_metadata_open

Add a parameter to dm_pool_metadata_open to indicate whether or not an
unformatted metadata area should be formatted.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-thin-metadata.c

@@ -624,7 +624,7 @@ static int __open_metadata(struct dm_pool_metadata *pmd)
 	return r;
 }
 
-static int __open_or_format_metadata(struct dm_pool_metadata *pmd)
+static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_device)
 {
 	int r, unformatted;
 
@@ -633,12 +633,12 @@ static int __open_or_format_metadata(struct dm_pool_metadata *pmd)
 		return r;
 
 	if (unformatted)
-		return __format_metadata(pmd);
-	else
-		return __open_metadata(pmd);
+		return format_device ? __format_metadata(pmd) : -EPERM;
+
+	return __open_metadata(pmd);
 }
 
-static int __create_persistent_data_objects(struct dm_pool_metadata *pmd)
+static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool format_device)
 {
 	int r;
 
@@ -650,7 +650,7 @@ static int __create_persistent_data_objects(struct dm_pool_metadata *pmd)
 		return PTR_ERR(pmd->bm);
 	}
 
-	r = __open_or_format_metadata(pmd);
+	r = __open_or_format_metadata(pmd, format_device);
 	if (r)
 		dm_block_manager_destroy(pmd->bm);
 
@@ -792,7 +792,8 @@ static int __commit_transaction(struct dm_pool_metadata *pmd)
 }
 
 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
-					       sector_t data_block_size)
+					       sector_t data_block_size,
+					       bool format_device)
 {
 	int r;
 	struct dm_pool_metadata *pmd;
@@ -809,7 +810,7 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
 	pmd->bdev = bdev;
 	pmd->data_block_size = data_block_size;
 
-	r = __create_persistent_data_objects(pmd);
+	r = __create_persistent_data_objects(pmd, format_device);
 	if (r) {
 		kfree(pmd);
 		return ERR_PTR(r);

drivers/md/dm-thin-metadata.h

@@ -38,7 +38,8 @@ typedef uint64_t dm_thin_id;
  * Reopens or creates a new, empty metadata volume.
  */
 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
-					       sector_t data_block_size);
+					       sector_t data_block_size,
+					       bool format_device);
 
 int dm_pool_metadata_close(struct dm_pool_metadata *pmd);
 

drivers/md/dm-thin.c

@@ -1712,7 +1712,7 @@ static struct pool *pool_create(struct mapped_device *pool_md,
 	struct pool *pool;
 	struct dm_pool_metadata *pmd;
 
-	pmd = dm_pool_metadata_open(metadata_dev, block_size);
+	pmd = dm_pool_metadata_open(metadata_dev, block_size, true);
 	if (IS_ERR(pmd)) {
 		*error = "Error creating metadata object";
 		return (struct pool *)pmd;