i_current_depth is used only for directory inode, but its space is
shared with i_gc_failures field used for regular inode, in order to
avoid affecting i_gc_failures' value, this patch fixes to initialize
the union's fields according to inode type.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>