On Mon, Mar 24, 2025 at 09:52:15PM +0000, Al Viro wrote: > 1) dget_parent(dentry) never returns NULL; if you have IS_ROOT(dentry) you > get an equivalent of dget(dentry). What do you want returned in that > case? xfs_filestream_get_parent is only called for regular files. IS_ROOT can probably only happen for partially connected trees on nfs exports, in which case we'd want NULL; > > 2) why bother with dget_parent() in the first place? What's wrong with > spin_lock(&dentry->d_lock); // stabilizes ->d_parent > dir = igrab(dentry->d_parent->d_inode); > spin_unlock(&dentry->d_lock); > > or, if you intended NULL for root, > spin_lock(&dentry->d_lock); // stabilizes ->d_parent > if (!IS_ROOT(dentry)) > dir = igrab(dentry->d_parent->d_inode); > spin_unlock(&dentry->d_lock); > > > Is there anything subtle I'm missing here? Nothing really, except that this probably feelt like poking a bit too much into internals.
