> On Mon, Nov 27, 2023 at 03:28:16PM +0000, Tao Lyu wrote: >> >> O_APPEND | O_DIRECT can be used to bypass the client cache for multiple threads writing data without caring of the orders (e.g., logs). >> >> Yes, to support O_APPEND | O_DIRECT, NFS must first support APPEND. >> But the key point is that looks like NFS has supported O_APPEND already. >> I can successfully open a file with "O_RDWR|O_APPEND". >> >> My confusion is why NFS supports O_RDWR and O_APPEND individually but does not support this combination. > Well, it does support O_RDWR|O_APPEND, just not with O_DIRECT? Hi Christoph, Yes, it just doesn't work with O_DIRECT. > Btw, I think an APPEND operation in NFS would be a very good idea, and > I'd love to work with interested parties in the IETF on it. Not that > we (Damien to be specific) plan to add support to Linux to also report > the actual offset an O_APPEND write wrote to through io_uring as we > have varios use cases for out of place write data stores for that. > It would be great to also support that programming model over NFS.
