From 263d3995c93c6020576f6c93506412a0b9d1e932 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Fri, 17 Feb 2017 18:43:57 +0000 Subject: [PATCH] Btrfs: try harder to migrate items to left sibling before splitting a leaf Before attempting to split a leaf we try to migrate items from the leaf to its right and left siblings. We start by trying to move items into the rigth sibling and, if the new item is meant to be inserted at the end of our leaf, we try to free from our leaf an amount of bytes equal to the number of bytes used by the new item, by setting the variable space_needed to the byte size of that new item. However if we fail to move enough items to the right sibling due to lack of space in that sibling, we then try to move items into the left sibling, and in that case we try to free an amount equal to the size of the new item from our leaf, when we need only to free an amount corresponding to the size of the new item minus the current free space of our leaf. So make sure that before we try to move items to the left sibling we do set the variable space_needed with a value corresponding to the new item's size minus the leaf's current free space. Signed-off-by: Filipe Manana Reviewed-by: Liu Bo --- fs/btrfs/ctree.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 1192bc7..1fb60ee 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -4159,6 +4159,9 @@ static noinline int push_for_double_split(struct btrfs_trans_handle *trans, /* try to push all the items before our slot into the next leaf */ slot = path->slots[0]; + space_needed = data_size; + if (slot > 0) + space_needed -= btrfs_leaf_free_space(fs_info, path->nodes[0]); ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot); if (ret < 0) return ret; @@ -4214,6 +4217,10 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans, if (wret < 0) return wret; if (wret) { + space_needed = data_size; + if (slot > 0) + space_needed -= btrfs_leaf_free_space(fs_info, + l); wret = push_leaf_left(trans, root, path, space_needed, space_needed, 0, (u32)-1); if (wret < 0) -- 2.7.4