[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>
---
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