From: Chris Mason Date: Fri, 2 Apr 2010 13:20:18 +0000 (-0400) Subject: Btrfs: add check for changed leaves in setup_leaf_for_split X-Git-Tag: v2.6.34-rc4~69^2 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=109f6aef5fc436f355ad027f4d97bd696df2049a Btrfs: add check for changed leaves in setup_leaf_for_split setup_leaf_for_split needs to drop the path and search again, and has checks to see if the item we want to split changed size. But, it misses the case where the leaf changed and now has enough room for the item we want to insert. This adds an extra check to make sure the leaf really needs splitting before we call btrfs_split_leaf(), which keeps us from trying to split a leaf with a single item. btrfs_split_leaf() will blindly split the single item leaf, leaving us with one good leaf and one empty leaf and then a crash. Signed-off-by: Chris Mason --- diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index c4bc570a396e..babf7fbaec84 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -3040,6 +3040,10 @@ static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans, if (ret > 0 || item_size != btrfs_item_size_nr(leaf, path->slots[0])) goto err; + /* the leaf has changed, it now has room. return now */ + if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len) + goto err; + if (key.type == BTRFS_EXTENT_DATA_KEY) { fi = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item);