On 05/14/2015 03:59 PM, Rik van Riel wrote: > On 05/14/2015 04:26 AM, Daniel Phillips wrote: >> Hi Rik, <> > > The issue is that things like ptrace, AIO, infiniband > RDMA, and other direct memory access subsystems can take > a reference to page A, which Tux3 clones into a new page B > when the process writes it. > > However, while the process now points at page B, ptrace, > AIO, infiniband, etc will still be pointing at page A. > All these problems can also happen with truncate+new-extending-write It is the responsibility of the application to take file/range locks to prevent these page-pinned problems. > This causes the process and the other subsystem to each > look at a different page, instead of at shared state, > causing ptrace to do nothing, AIO and RDMA data to be > invisible (or corrupted), etc... > Again these problems already exist. Consider each in-place-write being a truncate (punch hole) + new-write is that not the same? Cheers Boaz -- 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
