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. > 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. Thanks, Miklos
