Messages in this thread | | | Date | Mon, 17 Sep 2007 10:59:34 -0400 | Subject | Re: [PATCH] Wake up mandatory locks waiter on chmod | From | "J. Bruce Fields" <> |
| |
On Mon, Sep 17, 2007 at 10:37:56AM +0400, Pavel Emelyanov wrote: > J. Bruce Fields wrote: > > Is there a small chance that a lock may be applied after this check: > > > >> + mandatory = (inode->i_flock && MANDATORY_LOCK(inode)); > >> + > > > > but early enough that someone can still block on the lock while the file > > is still marked for mandatory locking? (And is the inode->i_flock check > > there really necessary?) > > There is, but as you have noticed:
OK, but why not just remove the inode->i_flock check there? I can't see how it helps anyway.
> > Well, there are probably worse races in the mandatory locking code. > > ...there are. The inode->i_lock is protected with lock_kernel() only > and is not in sync with any other checks for inodes. This is sad :( > but a good locking for locks is to be done...
I would also prefer a locking scheme that didn't rely on the BKL. That said, except for this race:
> > (For example, my impression is that a mandatory lock can be applied just > > after the locks_mandatory_area() checks but before the io actually > > completes.)
... I'm not aware of other races in the existing file-locking code. It sounds like you might be. Could you give specific examples?
--b. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |