Commit 3d976388 authored by David Sterba's avatar David Sterba
Browse files

btrfs: remove embedded block_group_cache::item 



The members ::used and ::flags are now in the block group cache
structure, the last one is chunk_objectid, but that's set to a fixed
value and otherwise unused. The item is constructed from a local
variable before write, so we can remove the embedded one from block
group.

Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent f93c63e5

fs/btrfs/block-group.c

+5 −11
Original line number Diff line number Diff line
@@ -1752,8 +1752,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) 
		read_extent_buffer(leaf, &bgi,

				   btrfs_item_ptr_offset(leaf, path->slots[0]),

				   sizeof(bgi));

		/* Duplicate as the item is still partially used */

		memcpy(&cache->item, &bgi, sizeof(bgi));

		/* cache::chunk_objectid is unused */

		cache->used = btrfs_block_group_used(&bgi);

		cache->flags = btrfs_block_group_flags(&bgi);

		if (!mixed &&
@@ -1879,12 +1878,9 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) 
			goto next;



		spin_lock(&block_group->lock);

		/*

		 * Copy partially filled item from the cache and ovewrite used

		 * that has the correct value

		 */

		memcpy(&item, &block_group->item, sizeof(item));

		btrfs_set_block_group_used(&item, block_group->used);

		btrfs_set_block_group_chunk_objectid(&item,

				BTRFS_FIRST_CHUNK_TREE_OBJECTID);

		btrfs_set_block_group_flags(&item, block_group->flags);

		memcpy(&key, &block_group->key, sizeof(key));

		spin_unlock(&block_group->lock);
@@ -1919,8 +1915,6 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used, 
		return -ENOMEM;



	cache->used = bytes_used;

	btrfs_set_block_group_chunk_objectid(&cache->item,

					     BTRFS_FIRST_CHUNK_TREE_OBJECTID);

	cache->flags = type;

	cache->last_byte_to_unpin = (u64)-1;

	cache->cached = BTRFS_CACHE_FINISHED;
@@ -2136,9 +2130,9 @@ static int write_one_cache_group(struct btrfs_trans_handle *trans, 


	leaf = path->nodes[0];

	bi = btrfs_item_ptr_offset(leaf, path->slots[0]);

	/* Partial copy of item, update the rest from memory */

	memcpy(&bgi, &cache->item, sizeof(bgi));

	btrfs_set_block_group_used(&bgi, cache->used);

	btrfs_set_block_group_chunk_objectid(&bgi,

			BTRFS_FIRST_CHUNK_TREE_OBJECTID);

	btrfs_set_block_group_flags(&bgi, cache->flags);

	write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));

	btrfs_mark_buffer_dirty(leaf);

fs/btrfs/block-group.h

+0 −1
Original line number Diff line number Diff line
@@ -44,7 +44,6 @@ struct btrfs_caching_control { 


struct btrfs_block_group_cache {

	struct btrfs_key key;

	struct btrfs_block_group_item item;

	struct btrfs_fs_info *fs_info;

	struct inode *inode;

	spinlock_t lock;

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