From: Olaf Hering <olaf@xxxxxxxxx> Till recently the expected length of bytes read by the daemon did depend on the context. It was either hv_start_fcopy or hv_do_fcopy. The daemon had a buffer size of two pages, which was much larger than needed. Now the expected length of bytes read by the daemon changed slightly. For START_FILE_COPY it is still the size of hv_start_fcopy. But for WRITE_TO_FILE and the other operations it is as large as the buffer that arrived via vmbus. In case of WRITE_TO_FILE that is slightly larger than a struct hv_do_fcopy. Since the buffer in the daemon was still larger everything was fine. Currently, the daemon reads only what is actually needed. The new buffer layout is as large as a struct hv_do_fcopy, for the WRITE_TO_FILE operation. Since the kernel expects a slightly larger size, hvt_op_read will return -EINVAL because the daemon will read slightly less than expected. Address this by restoring the expected buffer size in case of WRITE_TO_FILE. Fixes: 'c7e490fc23eb ("Drivers: hv: fcopy: convert to hv_utils_transport")' Fixes: '3f2baa8a7d2e ("Tools: hv: update buffer handling in hv_fcopy_daemon")' Signed-off-by: Olaf Hering <olaf@xxxxxxxxx> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- drivers/hv/hv_fcopy.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c index daa75bd41f86..2364281d8593 100644 --- a/drivers/hv/hv_fcopy.c +++ b/drivers/hv/hv_fcopy.c @@ -170,6 +170,10 @@ static void fcopy_send_data(struct work_struct *dummy) out_src = smsg_out; break; + case WRITE_TO_FILE: + out_src = fcopy_transaction.fcopy_msg; + out_len = sizeof(struct hv_do_fcopy); + break; default: out_src = fcopy_transaction.fcopy_msg; out_len = fcopy_transaction.recv_len; -- 2.14.1