On Tue, 15 Feb 2022 at 17:20, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Feb 15, 2022 at 04:17:11PM +0000, Matthew Wilcox wrote: > > On Tue, Feb 15, 2022 at 04:06:06PM +0000, Al Viro wrote: > > > On Tue, Feb 15, 2022 at 01:37:40PM +0000, Al Viro wrote: > > > > On Tue, Feb 15, 2022 at 10:56:29AM +0100, Miklos Szeredi wrote: > > > > > > > > > Doing "lock_rename() + lookup last components" would fix this race. > > > > > > "Fucking ugly" is inadequate for the likely results of that approach. > > > It's guaranteed to be a source of headache for pretty much ever after. So this is a fairly special situation. How about adding a new rwsem (could possibly be global or per-fs)? - acquired for read in lock_rename() before inode locks - acquired for write in do_linkat before inode locks, but only on retry Thanks, Miklos
