On Wed, Jun 15, 2016 at 03:09:23PM +0000, Trond Myklebust wrote: > As I said earlier, the problem with that is you end up artificially serialising buffered reads and buffered writes. If you actually want to be Posix compiant you need to serialize buffered reads against buffererd writes - it's just that most Linux file systems happen to get this wrong. > ??? The reads only need a shared lock in order to protect the I/O mode from flipping to O_DIRECT (and relying on page locks to protect against buffered writes). Which strictly speaking is not enough, although as said above most Linux filesystems get this wrong. If you indeed want to keep that (incorrect) behavior you need another lock. It's defintively not "simpler", though. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html