btrfs: rename extent buffer block group item accessors

Accessors defined by BTRFS_SETGET_FUNCS take a raw extent buffer and
manipulate the items there, there's no special prefix required. The
block group accessors had _disk_ because previously the names were
occupied by the on-stack accessors. As this has been addressed in the
previous patch, we can now unify the naming.
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -1521,14 +1521,14 @@ static inline u64 btrfs_stripe_devid_nr(struct extent_buffer *eb,
 /* struct btrfs_block_group_item */
 BTRFS_SETGET_STACK_FUNCS(stack_block_group_used, struct btrfs_block_group_item,
 			 used, 64);
-BTRFS_SETGET_FUNCS(disk_block_group_used, struct btrfs_block_group_item,
+BTRFS_SETGET_FUNCS(block_group_used, struct btrfs_block_group_item,
 			 used, 64);
 BTRFS_SETGET_STACK_FUNCS(stack_block_group_chunk_objectid,
 			struct btrfs_block_group_item, chunk_objectid, 64);
 
-BTRFS_SETGET_FUNCS(disk_block_group_chunk_objectid,
+BTRFS_SETGET_FUNCS(block_group_chunk_objectid,
 		   struct btrfs_block_group_item, chunk_objectid, 64);
-BTRFS_SETGET_FUNCS(disk_block_group_flags,
+BTRFS_SETGET_FUNCS(block_group_flags,
 		   struct btrfs_block_group_item, flags, 64);
 BTRFS_SETGET_STACK_FUNCS(stack_block_group_flags,
 			struct btrfs_block_group_item, flags, 64);

fs/btrfs/print-tree.c

@@ -266,9 +266,9 @@ void btrfs_print_leaf(struct extent_buffer *l)
 					    struct btrfs_block_group_item);
 			pr_info(
 		   "\t\tblock group used %llu chunk_objectid %llu flags %llu\n",
-				btrfs_disk_block_group_used(l, bi),
-				btrfs_disk_block_group_chunk_objectid(l, bi),
-				btrfs_disk_block_group_flags(l, bi));
+				btrfs_block_group_used(l, bi),
+				btrfs_block_group_chunk_objectid(l, bi),
+				btrfs_block_group_flags(l, bi));
 			break;
 		case BTRFS_CHUNK_ITEM_KEY:
 			print_chunk(l, btrfs_item_ptr(l, i,