On 12/11/20 10:33 AM, Matthew Wilcox wrote: > On Fri, Dec 11, 2020 at 09:05:26AM -0700, Jens Axboe wrote: >> On 12/10/20 7:45 PM, Al Viro wrote: >>> So how hard are your "we don't want to block here" requirements? Because >>> the stuff you do after complete_walk() can easily be much longer than >>> everything else. >> >> Ideally it'd extend a bit beyond the RCU lookup, as things like proc >> resolution will still fail with the proposed patch. But that's not a >> huge deal to me, I consider the dentry lookup to be Good Enough. > > FWIW, /proc/$pid always falls back to REF walks. Here's a patch from > one of my colleagues that aims to fix that. > > https://lore.kernel.org/linux-fsdevel/20201204000212.773032-1-stephen.s.brennan@xxxxxxxxxx/ > > Maybe you had one of the other parts of /proc in mind? Yes, it is/was /proc/self/ specifically, which the patch won't really help. But it's not like it's a huge issue, and I'm quite happy (for now) to just have that -EOPNOTSUPP on open as it does. -- Jens Axboe
