Commit 4b52dff6 authored by Chris Mason's avatar Chris Mason Committed by David Woodhouse
Browse files

Btrfs: Fix super block updates during transaction commit 



The super block written during commit was not consistent with the state of
the trees.  This change adds an in-memory copy of the super so that we can
make sure to write out consistent data during a commit.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 79c44584

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -306,6 +306,7 @@ struct btrfs_fs_info { 
	u64 generation;

	struct btrfs_transaction *running_transaction;

	struct btrfs_super_block *disk_super;

	struct btrfs_super_block super_copy;

	struct buffer_head *sb_buffer;

	struct super_block *sb;

	struct inode *btree_inode;

fs/btrfs/disk-io.c

+2 −3
Original line number Diff line number Diff line
@@ -471,6 +471,8 @@ struct btrfs_root *open_ctree(struct super_block *sb) 
	if (!fs_info->sb_buffer)

		goto fail_iput;

	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;

	fs_info->disk_super = disk_super;

	memcpy(&fs_info->super_copy, disk_super, sizeof(fs_info->super_copy));



	if (!btrfs_super_root(disk_super))

		goto fail_sb_buffer;
@@ -479,7 +481,6 @@ struct btrfs_root *open_ctree(struct super_block *sb) 
		     btrfs_super_total_blocks(disk_super) <<

		     fs_info->btree_inode->i_blkbits);



	fs_info->disk_super = disk_super;



	if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,

		    sizeof(disk_super->magic))) {
@@ -527,8 +528,6 @@ int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root 
	int ret;

	struct buffer_head *bh = root->fs_info->sb_buffer;



	btrfs_set_super_root(root->fs_info->disk_super,

			     bh_blocknr(root->fs_info->tree_root->node));

	lock_buffer(bh);

	WARN_ON(atomic_read(&bh->b_count) < 1);

	clear_buffer_dirty(bh);

fs/btrfs/extent-tree.c

+8 −8
Original line number Diff line number Diff line
@@ -796,8 +796,8 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct 


	for (i = 0; i < extent_root->fs_info->extent_tree_insert_nr; i++) {

		ins.objectid = extent_root->fs_info->extent_tree_insert[i];

		super_blocks_used = btrfs_super_blocks_used(info->disk_super);

		btrfs_set_super_blocks_used(info->disk_super,

		super_blocks_used = btrfs_super_blocks_used(&info->super_copy);

		btrfs_set_super_blocks_used(&info->super_copy,

					    super_blocks_used + 1);

		ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,

					sizeof(extent_item));
@@ -892,8 +892,8 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root 
			BUG_ON(ret);

		}



		super_blocks_used = btrfs_super_blocks_used(info->disk_super);

		btrfs_set_super_blocks_used(info->disk_super,

		super_blocks_used = btrfs_super_blocks_used(&info->super_copy);

		btrfs_set_super_blocks_used(&info->super_copy,

					    super_blocks_used - num_blocks);

		ret = btrfs_del_item(trans, extent_root, path);

		if (ret) {
@@ -1032,7 +1032,7 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root 
		info->extent_tree_prealloc_nr = 0;

	}

	if (search_end == (u64)-1)

		search_end = btrfs_super_total_blocks(info->disk_super);

		search_end = btrfs_super_total_blocks(&info->super_copy);

	if (hint_block) {

		block_group = btrfs_lookup_block_group(info, hint_block);

		block_group = btrfs_find_block_group(root, block_group,
@@ -1361,8 +1361,8 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans, 
		}

	}



	super_blocks_used = btrfs_super_blocks_used(info->disk_super);

	btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +

	super_blocks_used = btrfs_super_blocks_used(&info->super_copy);

	btrfs_set_super_blocks_used(&info->super_copy, super_blocks_used +

				    num_blocks);

	ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,

				sizeof(extent_item));
@@ -1737,7 +1737,7 @@ int btrfs_read_block_groups(struct btrfs_root *root) 
					   BTRFS_BLOCK_GROUP_AVAIL);

		}

		if (key.objectid >=

		    btrfs_super_total_blocks(info->disk_super))

		    btrfs_super_total_blocks(&info->super_copy))

			break;

	}

fs/btrfs/super.c

+1 −1
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, 
static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)

{

	struct btrfs_root *root = btrfs_sb(dentry->d_sb);

	struct btrfs_super_block *disk_super = root->fs_info->disk_super;

	struct btrfs_super_block *disk_super = &root->fs_info->super_copy;



	buf->f_namelen = BTRFS_NAME_LEN;

	buf->f_blocks = btrfs_super_total_blocks(disk_super);

fs/btrfs/transaction.c

+6 −2
Original line number Diff line number Diff line
@@ -380,6 +380,12 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
		else

			prev_trans->use_count++;

	}

	btrfs_set_super_generation(&root->fs_info->super_copy,

				   cur_trans->transid);

	btrfs_set_super_root(&root->fs_info->super_copy,

			     bh_blocknr(root->fs_info->tree_root->node));

	memcpy(root->fs_info->disk_super, &root->fs_info->super_copy,

	       sizeof(root->fs_info->super_copy));

	mutex_unlock(&root->fs_info->trans_mutex);

	mutex_unlock(&root->fs_info->fs_mutex);

	ret = btrfs_write_and_wait_transaction(trans, root);
@@ -389,8 +395,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, 
		put_transaction(prev_trans);

		mutex_unlock(&root->fs_info->trans_mutex);

	}

	btrfs_set_super_generation(root->fs_info->disk_super,

				   cur_trans->transid);

	BUG_ON(ret);

	write_ctree_super(trans, root);