On Thu, Feb 05, 2026 at 11:53:51PM +0000, Al Viro wrote: > On Wed, Feb 04, 2026 at 11:45:17PM -0500, Waiman Long wrote: > > > @@ -70,6 +74,8 @@ void chroot_fs_refs(const struct path *old_root, const > > struct> > > count++; > > path_get(new_root); > > } > > + count += fs->pwd_xrefs; > > + fs->pwd_xrefs = 0; > > write_sequnlock(&fs->seq); > > Nope - you only need that for threads that have ->pwd equal to old_root. > Incidentally, I'd forgotten about that sucker - it kills the idea of > fdget-like tricks dead, more's the pity. Third-party modification of > task->fs->pwd (under task->lock and task->fs->seq), possible even with > task->fs->users == 1. > > FWIW, I'm going through the fs_struct uses at the moment; will post > whatever I get when I go down (or earlier, in the unlikely case it doesn't > spill to tomorrow morning), will keep posting incremental followups > until the documentation is done. I'm sick and tired of half-finished > docs - let's see if I can push through that one this way ;-/ >
All right, I'm going down - it's 3am here; the current notes are at http://ftp.linux.org.uk/people/viro/fs_struct, will update when I get up tomorrow^Wtoday.
