Commit bce4eae9 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Fix balance_level to free the middle block if there is room in the left one 



balance level starts by trying to empty the middle block, and then
pushes from the right to the middle.  This might empty the right block
and leave a small number of pointers in the middle.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 971a1f66

fs/btrfs/ctree.c

+28 −7
Original line number Diff line number Diff line
@@ -789,7 +789,7 @@ static int balance_level(struct btrfs_trans_handle *trans, 
	/* first, try to make some room in the middle buffer */

	if (left) {

		orig_slot += btrfs_header_nritems(left);

		wret = push_node_left(trans, root, left, mid, 0);

		wret = push_node_left(trans, root, left, mid, 1);

		if (wret < 0)

			ret = wret;

		if (btrfs_header_nritems(mid) < 2)
@@ -844,6 +844,11 @@ static int balance_level(struct btrfs_trans_handle *trans, 
			ret = wret;

			goto enospc;

		}

		if (wret == 1) {

			wret = push_node_left(trans, root, left, mid, 1);

			if (wret < 0)

				ret = wret;

		}

		BUG_ON(wret == 1);

	}

	if (btrfs_header_nritems(mid) == 0) {
@@ -1252,17 +1257,27 @@ static int push_node_left(struct btrfs_trans_handle *trans, 
	WARN_ON(btrfs_header_generation(src) != trans->transid);

	WARN_ON(btrfs_header_generation(dst) != trans->transid);



	if (!empty && src_nritems <= 2)

	if (!empty && src_nritems <= 8)

		return 1;



	if (push_items <= 0) {

		return 1;

	}



	if (empty)

	if (empty) {

		push_items = min(src_nritems, push_items);

	else

		push_items = min(src_nritems - 2, push_items);

		if (push_items < src_nritems) {

			/* leave at least 8 pointers in the node if

			 * we aren't going to empty it

			 */

			if (src_nritems - push_items < 8) {

				if (push_items <= 8)

					return 1;

				push_items -= 8;

			}

		}

	} else

		push_items = min(src_nritems - 8, push_items);



	copy_extent_buffer(dst, src,

			   btrfs_node_key_ptr_offset(dst_nritems),
@@ -1308,13 +1323,19 @@ static int balance_node_right(struct btrfs_trans_handle *trans, 
	src_nritems = btrfs_header_nritems(src);

	dst_nritems = btrfs_header_nritems(dst);

	push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;

	if (push_items <= 0)

	if (push_items <= 0) {

		return 1;

	}



	if (src_nritems < 4) {

		return 1;

	}



	max_push = src_nritems / 2 + 1;

	/* don't try to empty the node */

	if (max_push >= src_nritems)

	if (max_push >= src_nritems) {

		return 1;

	}



	if (max_push < push_items)

		push_items = max_push;

fs/btrfs/extent-tree.c

+2 −2
Original line number Diff line number Diff line
@@ -306,13 +306,13 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root, 
	int bit;

	int ret;

	int full_search = 0;

	int factor = 8;

	int factor = 10;



	block_group_cache = &info->block_group_cache;

	total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);



	if (!owner)

		factor = 8;

		factor = 10;



	bit = block_group_state_bits(data);