dm persistent data: tidy transaction manager creation fns

Tidy the transaction manager creation functions.

They no longer lock the superblock.  Superblock locking is pulled out to
the caller.

Also export dm_bm_write_lock_zero.

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

@@ -418,8 +418,7 @@ static int init_pmd(struct dm_pool_metadata *pmd,
 	struct dm_block *sblock;
 
 	if (create) {
-		r = dm_tm_create_with_sm(bm, THIN_SUPERBLOCK_LOCATION,
-					 &sb_validator, &tm, &sm, &sblock);
+		r = dm_tm_create_with_sm(bm, THIN_SUPERBLOCK_LOCATION, &tm, &sm);
 		if (r < 0) {
 			DMERR("tm_create_with_sm failed");
 			return r;
@@ -428,38 +427,51 @@ static int init_pmd(struct dm_pool_metadata *pmd,
 		data_sm = dm_sm_disk_create(tm, nr_blocks);
 		if (IS_ERR(data_sm)) {
 			DMERR("sm_disk_create failed");
-			dm_tm_unlock(tm, sblock);
 			r = PTR_ERR(data_sm);
 			goto bad;
 		}
-	} else {
-		struct thin_disk_superblock *disk_super = NULL;
-		size_t space_map_root_offset =
-			offsetof(struct thin_disk_superblock, metadata_space_map_root);
 
-		r = dm_tm_open_with_sm(bm, THIN_SUPERBLOCK_LOCATION,
-				       &sb_validator, space_map_root_offset,
-				       SPACE_MAP_ROOT_SIZE, &tm, &sm, &sblock);
+		/*
+		 * We cycle the superblock to let the validator do its stuff.
+		 */
+		r = dm_bm_write_lock_zero(bm, THIN_SUPERBLOCK_LOCATION, &sb_validator, &sblock);
 		if (r < 0) {
-			DMERR("tm_open_with_sm failed");
+			DMERR("couldn't lock superblock");
+			goto bad;
+		}
+
+		dm_bm_unlock(sblock);
+
+	} else {
+		struct thin_disk_superblock *disk_super;
+
+		r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, &sb_validator, &sblock);
+		if (r < 0) {
+			DMERR("couldn't read superblock");
 			return r;
 		}
 
 		disk_super = dm_block_data(sblock);
+		r = dm_tm_open_with_sm(bm, THIN_SUPERBLOCK_LOCATION,
+				       disk_super->metadata_space_map_root,
+				       sizeof(disk_super->metadata_space_map_root),
+				       &tm, &sm);
+		if (r < 0) {
+			DMERR("tm_open_with_sm failed");
+			dm_bm_unlock(sblock);
+			return r;
+		}
+
 		data_sm = dm_sm_disk_open(tm, disk_super->data_space_map_root,
 					  sizeof(disk_super->data_space_map_root));
 		if (IS_ERR(data_sm)) {
 			DMERR("sm_disk_open failed");
+			dm_bm_unlock(sblock);
 			r = PTR_ERR(data_sm);
 			goto bad;
 		}
-	}
 
-
-	r = dm_tm_unlock(tm, sblock);
-	if (r < 0) {
-		DMERR("couldn't unlock superblock");
-		goto bad_data_sm;
+		dm_bm_unlock(sblock);
 	}
 
 	pmd->bm = bm;

drivers/md/persistent-data/dm-block-manager.c

@@ -565,6 +565,7 @@ int dm_bm_write_lock_zero(struct dm_block_manager *bm,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(dm_bm_write_lock_zero);
 
 int dm_bm_unlock(struct dm_block *b)
 {

drivers/md/persistent-data/dm-transaction-manager.c

@@ -310,12 +310,10 @@ struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm)
 
 static int dm_tm_create_internal(struct dm_block_manager *bm,
 				 dm_block_t sb_location,
-				 struct dm_block_validator *sb_validator,
-				 size_t root_offset, size_t root_max_len,
 				 struct dm_transaction_manager **tm,
 				 struct dm_space_map **sm,
-				 struct dm_block **sblock,
-				 int create)
+				 int create,
+				 void *sm_root, size_t sm_len)
 {
 	int r;
 
@@ -330,64 +328,43 @@ static int dm_tm_create_internal(struct dm_block_manager *bm,
 	}
 
 	if (create) {
-		r = dm_bm_write_lock_zero(dm_tm_get_bm(*tm), sb_location,
-					  sb_validator, sblock);
-		if (r < 0) {
-			DMERR("couldn't lock superblock");
-			goto bad1;
-		}
-
 		r = dm_sm_metadata_create(*sm, *tm, dm_bm_nr_blocks(bm),
 					  sb_location);
 		if (r) {
 			DMERR("couldn't create metadata space map");
-			goto bad2;
+			goto bad;
 		}
 
 	} else {
-		r = dm_bm_write_lock(dm_tm_get_bm(*tm), sb_location,
-				     sb_validator, sblock);
-		if (r < 0) {
-			DMERR("couldn't lock superblock");
-			goto bad1;
-		}
-
-		r = dm_sm_metadata_open(*sm, *tm,
-					dm_block_data(*sblock) + root_offset,
-					root_max_len);
+		r = dm_sm_metadata_open(*sm, *tm, sm_root, sm_len);
 		if (r) {
 			DMERR("couldn't open metadata space map");
-			goto bad2;
+			goto bad;
 		}
 	}
 
 	return 0;
 
-bad2:
-	dm_tm_unlock(*tm, *sblock);
-bad1:
+bad:
 	dm_tm_destroy(*tm);
+	dm_sm_destroy(*sm);
 	return r;
 }
 
 int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
-			 struct dm_block_validator *sb_validator,
 			 struct dm_transaction_manager **tm,
-			 struct dm_space_map **sm, struct dm_block **sblock)
+			 struct dm_space_map **sm)
 {
-	return dm_tm_create_internal(bm, sb_location, sb_validator,
-				     0, 0, tm, sm, sblock, 1);
+	return dm_tm_create_internal(bm, sb_location, tm, sm, 1, NULL, 0);
 }
 EXPORT_SYMBOL_GPL(dm_tm_create_with_sm);
 
 int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
-		       struct dm_block_validator *sb_validator,
-		       size_t root_offset, size_t root_max_len,
+		       void *sm_root, size_t root_len,
 		       struct dm_transaction_manager **tm,
-		       struct dm_space_map **sm, struct dm_block **sblock)
+		       struct dm_space_map **sm)
 {
-	return dm_tm_create_internal(bm, sb_location, sb_validator, root_offset,
-				     root_max_len, tm, sm, sblock, 0);
+	return dm_tm_create_internal(bm, sb_location, tm, sm, 0, sm_root, root_len);
 }
 EXPORT_SYMBOL_GPL(dm_tm_open_with_sm);
 

drivers/md/persistent-data/dm-transaction-manager.h

@@ -115,16 +115,17 @@ struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm);
  *
  * Returns a tm that has an open transaction to write the new disk sm.
  * Caller should store the new sm root and commit.
+ *
+ * The superblock location is passed so the metadata space map knows it
+ * shouldn't be used.
  */
 int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
-			 struct dm_block_validator *sb_validator,
 			 struct dm_transaction_manager **tm,
-			 struct dm_space_map **sm, struct dm_block **sblock);
+			 struct dm_space_map **sm);
 
 int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
-		       struct dm_block_validator *sb_validator,
-		       size_t root_offset, size_t root_max_len,
+		       void *sm_root, size_t root_len,
 		       struct dm_transaction_manager **tm,
-		       struct dm_space_map **sm, struct dm_block **sblock);
+		       struct dm_space_map **sm);
 
 #endif	/* _LINUX_DM_TRANSACTION_MANAGER_H */