2fbe8c8a Sat Jul 16 20:38:06 CDT 2011 Al Viro <viro@zeniv.linux.org.uk> get rid of useless dget_parent() in fs/btrfs/ioctl.c
both callers there have dentry->d_parent stabilized by the fact that their caller had obtained dentry from lookup_one_len() and had not dropped ->i_mutex on parent since then.