On Thu, 2011-01-20 at 10:37 +1100, Nick Piggin wrote: > On Thu, Jan 20, 2011 at 10:31 AM, Trond Myklebust > <Trond.Myklebust@xxxxxxxxxx> wrote: > > On Thu, 2011-01-20 at 10:26 +1100, Nick Piggin wrote: > >> On Thu, Jan 20, 2011 at 10:25 AM, Trond Myklebust > > >> > Also, why is EIO the correct reply when no bytes were read/written? Why > >> > shouldn't the VFS aio code be able to cope with a zero byte reply? > >> > >> What would it do? > > > > Just return that zero byte reply to userland. > > > > zero bytes is a valid reply for ordinary read() and write(), so why > > should we have to do anything different for aio_read()/aio_write()? > > It doesn't give userspace much to do. zero reply from read means > EOF. Zero reply from write is pretty useless, I don't think we do it > in the buffered write path -- we either ensure we write at least > something or have a meaningful error to return. zero reply from read means EOF _or_ user supplied a zero length buffer. zero reply from write may also be useless, but it is a valid value. It can simply mean the user supplied a zero length buffer. -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com -- 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
