On Fri, Feb 9, 2024 at 3:27 PM Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > > On Fri, 9 Feb 2024 at 13:12, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > > I think this race can happen even if we remove killable_ > > Without _killable, the loop will exit with iocachectr >= 0, hence the > FUSE_I_CACHE_IO_MODE will not be cleared. > > > not sure - anyway, with fuse passthrough there is another error > > condition: > > > > /* > > * Check if inode entered passthrough io mode while waiting for parallel > > * dio write completion. > > */ > > if (fuse_inode_backing(fi)) > > err = -ETXTBSY; > > > > But in this condition, all waiting tasks should abort the wait, > > so it does not seem a problem to clean the flag. > > Ah, this complicates things. But I think it's safe to clear > FUSE_I_CACHE_IO_MODE in this case, since other > fuse_inode_get_io_cache() calls will also fail. > Right. > > Anyway, IMO it is better to set the flag before every wait and on > > success. Like below. > > This would still have the race, since there will be a window during > which the FUSE_I_CACHE_IO_MODE flag has been cleared and new parallel > writes can start, even though there are one or more waiters for cached > open. > > Not that this would be a problem in practice, but I also don't see > removing the _killable being a big issue. ok. Remove killable. Pushed branches fuse_io_mode-090224 and fuse-backing-fd-090224 with requested fixes. Note that I had to update libfuse fuse-backing-fd branch, because when removing FOPEN_CACHE_IO, I changed the constant value of FOPEN_PASSTHOUGH. Passes my sanity tests. Bernd, please verify that I did not break anything on your end. Thanks, Amir.
