raw-posix: Use pread/pwrite instead of lseek+read/write This patch combines the lseek+read/write calls to use pread/pwrite instead. This will result in fewer system calls and is already used by AIO. Thanks to Jan Kiszka <jan.kiszka@siemens.com> for identifying excessive lseek and Christoph Hellwig <hch@lst.de> for confirming that this approach should work. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>