On Wed, Feb 03, 2010 at 03:04:19AM +0000, Al Viro wrote: > On Tue, Feb 02, 2010 at 11:19:52AM -0800, Eric W. Biederman wrote: > > > If we are going to take a lock this seems as sane as any. > > > > Do we want to honor oops_in_progress aka bust_spinlocks here? > > > > Perhaps just: > > if (oops_in_progress) > > return buf; > > > > To guarantee we get the rest of a panic message out of the kernel. > > Hmm... There's another fun issue - we would want local_irq_disable() / > local_irq_enable() in d_move_locked and local_irq_save/local_irq_restore() > in dname_string(), AFAICT. > > OK, here's what I've got from moving in that direction. Folks, how does > that one look to you? I'm not too happy about explicit manipulations > with irq flags in there, so any suggestions would be welcome. Argh. No, it's not at all better. Moreover, even read_seqbegin variant is b0rken if we ever do that under ->d_lock. CPU1:A: grabs dentry->d_lock CPU2:B: calls d_move_locked() CPU2:B: grabs rename_lock CPU2:B: spins on dentry->d_lock CPU1:A: calls printk with %pd dentry CPU1:A: spins waiting for rename_lock writer to release it So much for that approach ;-/ -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
