Re: [Libguestfs] [nbdkit PATCH 3/7] RFC: protocol: Only send EOVERFLOW when valid

Previously, we were squashing EOVERFLOW into EINVAL; continue to do so at points in the protocol where the client may not be expecting EOVERFLOW. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- server/protocol.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/server/protocol.c b/server/protocol.c index a52bb56..0a9f73c 100644 --- a/server/protocol.c +++ b/server/protocol.c @@ -326,7 +326,7 @@ skip_over_write_buffer (int sock, size_t count) /* Convert a system errno to an NBD_E* error code. */ static int -nbd_errno (int error) +nbd_errno (int error, bool flag_df) { switch (error) { case 0: @@ -349,7 +349,9 @@ nbd_errno (int error) return NBD_ESHUTDOWN; #endif case EOVERFLOW: - return NBD_EOVERFLOW; + if (flag_df) + return NBD_EOVERFLOW; + /* fallthrough */ case EINVAL: default: return NBD_EINVAL; @@ -368,7 +370,7 @@ send_simple_reply (struct connection *conn, reply.magic = htobe32 (NBD_SIMPLE_REPLY_MAGIC); reply.handle = handle; - reply.error = htobe32 (nbd_errno (error)); + reply.error = htobe32 (nbd_errno (error, false)); r = conn->send (conn, &reply, sizeof reply); if (r == -1) { @@ -573,7 +575,8 @@ send_structured_reply_block_status (struct connection *conn, static int send_structured_reply_error (struct connection *conn, - uint64_t handle, uint16_t cmd, uint32_t error) + uint64_t handle, uint16_t cmd, uint16_t flags, + uint32_t error) { ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&conn->write_lock); struct structured_reply reply; @@ -593,7 +596,7 @@ send_structured_reply_error (struct connection *conn, } /* Send the error. */ - error_data.error = htobe32 (nbd_errno (error)); + error_data.error = htobe32 (nbd_errno (error, flags & NBD_CMD_FLAG_DF)); error_data.len = htobe16 (0); r = conn->send (conn, &error_data, sizeof error_data); if (r == -1) { @@ -737,7 +740,8 @@ protocol_recv_request_send_reply (struct connection *conn) extents); } else - return send_structured_reply_error (conn, request.handle, cmd, error); + return send_structured_reply_error (conn, request.handle, cmd, flags, + error); } else return send_simple_reply (conn, request.handle, cmd, buf, count, error); -- 2.20.1