On Tue, Nov 27, 2018 at 11:05 AM Jan Kara <jack@xxxxxxx> wrote: > > On Tue 27-11-18 17:57:12, PanBian wrote: > > I am not quite sure about the actual execution logic. But I guess new_dentry > > reference may be dropped outside vfs_rename in cocurrent executions. > > Otherwise, there is no need to acquire & drop new_dentry reference as it > > is always alive along vfs_rename. > > I don't think that's the case. The dget() - dput() pair just looks > superfluous to me in vfs_rename(). Am I missing something Miklos? I think those are to protect against d_delete() called from fs to reset d_inode. The caller indeed has to hold one ref anyway. So not superfluous, but only needed due to d_delete() and not to protect against freeing of dentry. Thanks, Miklos
