On Fri, Jul 07, 2017 at 03:28:11PM +0200, Gioh Kim wrote: > Before __d_unalias(), the dentry and parent of the dentry > are locked. But I wonder how I can assure of existence of the > alias and the parent of the alias. > > Where is the code to lock alias and alias->d_parent? Nowhere. Why the hell would you want to lock them? > What will happend if alias->d_parent be deleted by another process? Huh? As soon as you've grabbed ->s_vfs_rename_mutex, ->d_parent of everything on that filesystem is stable - and positive. Moreover, any positive dentry with references held (in particular, anyone's parent) is going to remain such for as long as those references are held.
