Btrfs: reference counts on data extents (6407bf6d) · Commits · e / devices / android_kernel_fairphone_FP4

fs/btrfs/TODO

+3 −0

Original line number	Diff line number	Diff line
		@@ -8,7 +8,10 @@
		* Add block mapping tree (simple dm layer)
		* Add simple tree locking (semaphore per tree)
		* Make allocator smarter
		* make level a field in header
		* add a block group to struct inode
		* Make directory hashing work on 32 bit
		* Make sure nobh stuff is working properly for cows
		* Do actual block accounting
		* Check compat and incompat flags on the inode
		* Add virtual filesystems, mountable snapshots

fs/btrfs/ctree.h

+5 −4

Original line number	Diff line number	Diff line
		@@ -9,10 +9,11 @@ struct btrfs_transaction;

		#define BTRFS_MAGIC "_BtRfS_M"

		#define BTRFS_ROOT_TREE_OBJECTID 1
		#define BTRFS_EXTENT_TREE_OBJECTID 2
		#define BTRFS_INODE_MAP_OBJECTID 3
		#define BTRFS_FS_TREE_OBJECTID 4
		#define BTRFS_ROOT_TREE_OBJECTID 1ULL
		#define BTRFS_EXTENT_TREE_OBJECTID 2ULL
		#define BTRFS_INODE_MAP_OBJECTID 3ULL
		#define BTRFS_FS_TREE_OBJECTID 4ULL
		#define BTRFS_FIRST_FREE_OBJECTID 5ULL

		/*
		* we can actually store much bigger names, but lets not confuse the rest

fs/btrfs/extent-tree.c

+70 −17

Original line number	Diff line number	Diff line
		@@ -13,7 +13,7 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
		btrfs_root *extent_root);

		static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		*root, u64 blocknr)
		*root, u64 blocknr, u64 num_blocks)
		{
		struct btrfs_path path;
		int ret;
		@@ -29,7 +29,7 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		key.objectid = blocknr;
		key.flags = 0;
		btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
		key.offset = 1;
		key.offset = num_blocks;
		ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
		0, 1);
		if (ret != 0)
		@@ -48,7 +48,7 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		}

		static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		root, u64 blocknr, u32 refs)
		root, u64 blocknr, u64 num_blocks, u32 refs)
		{
		struct btrfs_path path;
		int ret;
		@@ -57,7 +57,7 @@ static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
		struct btrfs_extent_item *item;
		btrfs_init_path(&path);
		key.objectid = blocknr;
		key.offset = 1;
		key.offset = num_blocks;
		key.flags = 0;
		btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
		ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
		@@ -76,17 +76,34 @@ int btrfs_inc_ref(struct btrfs_trans_handle trans, struct btrfs_root root,
		{
		u64 blocknr;
		struct btrfs_node *buf_node;
		struct btrfs_leaf *buf_leaf;
		struct btrfs_disk_key *key;
		struct btrfs_file_extent_item *fi;
		int i;
		int leaf;
		int ret;

		if (!root->ref_cows)
		return 0;
		buf_node = btrfs_buffer_node(buf);
		if (btrfs_is_leaf(buf_node))
		return 0;

		leaf = btrfs_is_leaf(buf_node);
		buf_leaf = btrfs_buffer_leaf(buf);
		for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
		if (leaf) {
		key = &buf_leaf->items[i].key;
		if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
		continue;
		fi = btrfs_item_ptr(buf_leaf, i,
		struct btrfs_file_extent_item);
		ret = inc_block_ref(trans, root,
		btrfs_file_extent_disk_blocknr(fi),
		btrfs_file_extent_disk_num_blocks(fi));
		BUG_ON(ret);
		} else {
		blocknr = btrfs_node_blockptr(buf_node, i);
		inc_block_ref(trans, root, blocknr);
		ret = inc_block_ref(trans, root, blocknr, 1);
		BUG_ON(ret);
		}
		}
		return 0;
		}
		@@ -469,6 +486,37 @@ struct buffer_head btrfs_alloc_free_block(struct btrfs_trans_handle trans,
		return buf;
		}

		static int drop_leaf_ref(struct btrfs_trans_handle *trans,
		struct btrfs_root root, struct buffer_head cur)
		{
		struct btrfs_disk_key *key;
		struct btrfs_leaf *leaf;
		struct btrfs_file_extent_item *fi;
		int i;
		int nritems;
		int ret;

		BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
		leaf = btrfs_buffer_leaf(cur);
		nritems = btrfs_header_nritems(&leaf->header);
		for (i = 0; i < nritems; i++) {
		key = &leaf->items[i].key;
		if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
		continue;
		fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
		/*
		* FIXME make sure to insert a trans record that
		* repeats the snapshot del on crash
		*/
		ret = btrfs_free_extent(trans, root,
		btrfs_file_extent_disk_blocknr(fi),
		btrfs_file_extent_disk_num_blocks(fi),
		0);
		BUG_ON(ret);
		}
		return 0;
		}

		/*
		* helper function for drop_snapshot, this walks down the tree dropping ref
		* counts as it goes.
		@@ -483,28 +531,33 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
		u32 refs;

		ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr,
		&refs);
		1, &refs);
		BUG_ON(ret);
		if (refs > 1)
		goto out;
		/*
		* walk down to the last node level and free all the leaves
		*/
		while(*level > 0) {
		while(*level >= 0) {
		cur = path->nodes[*level];
		if (path->slots[*level] >=
		btrfs_header_nritems(btrfs_buffer_header(cur)))
		break;
		if (*level == 0) {
		ret = drop_leaf_ref(trans, root, cur);
		BUG_ON(ret);
		break;
		}
		blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
		path->slots[*level]);
		ret = lookup_block_ref(trans, root, blocknr, &refs);
		if (refs != 1 \|\| *level == 1) {
		ret = lookup_block_ref(trans, root, blocknr, 1, &refs);
		BUG_ON(ret);
		if (refs != 1) {
		path->slots[*level]++;
		ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
		BUG_ON(ret);
		continue;
		}
		BUG_ON(ret);
		next = read_tree_block(root, blocknr);
		if (path->nodes[*level-1])
		btrfs_block_release(root, path->nodes[*level-1]);
		@@ -513,8 +566,8 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
		path->slots[*level] = 0;
		}
		out:
		ret = btrfs_free_extent(trans, root, path->nodes[*level]->b_blocknr,
		1, 1);
		ret = btrfs_free_extent(trans, root,
		path->nodes[*level]->b_blocknr, 1, 1);
		btrfs_block_release(root, path->nodes[*level]);
		path->nodes[*level] = NULL;
		*level += 1;
		@@ -544,10 +597,10 @@ static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
		ret = btrfs_free_extent(trans, root,
		path->nodes[*level]->b_blocknr,
		1, 1);
		BUG_ON(ret);
		btrfs_block_release(root, path->nodes[*level]);
		path->nodes[*level] = NULL;
		*level = i + 1;
		BUG_ON(ret);
		}
		}
		return 1;

fs/btrfs/inode-map.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -25,6 +25,7 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
		if (fs_root->fs_info->last_inode_alloc_dirid == dirid)
		search_start = fs_root->fs_info->last_inode_alloc;

		search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
		search_key.objectid = search_start;
		search_key.flags = 0;
		btrfs_set_key_type(&search_key, BTRFS_INODE_MAP_ITEM_KEY);

fs/btrfs/super.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -700,7 +700,7 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock,
		static int btrfs_prepare_write(struct file file, struct page page,
		unsigned from, unsigned to)
		{
		return block_prepare_write(page, from, to, btrfs_get_block);
		return nobh_prepare_write(page, from, to, btrfs_get_block);
		}

		static void btrfs_write_super(struct super_block *sb)
		@@ -721,7 +721,7 @@ static int btrfs_readpages(struct file file, struct address_space mapping,

		static int btrfs_writepage(struct page page, struct writeback_control wbc)
		{
		return block_write_full_page(page, btrfs_get_block, wbc);
		return nobh_writepage(page, btrfs_get_block, wbc);
		}

		static int btrfs_get_sb(struct file_system_type *fs_type,
		@@ -768,7 +768,7 @@ static struct address_space_operations btrfs_aops = {
		.writepage = btrfs_writepage,
		.sync_page = block_sync_page,
		.prepare_write = btrfs_prepare_write,
		.commit_write = generic_commit_write,
		.commit_write = nobh_commit_write,
		};

		static struct inode_operations btrfs_file_inode_operations = {