From 4500632f60fa0d85e4101c374898cdf9b7b0cfac Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Tue, 1 Mar 2016 13:06:02 -0500 Subject: nfsd: Lower NFSv4.1 callback message size limit The maximum size of a backchannel message on RPC-over-RDMA depends on the connection's inline threshold. Today that threshold is typically 1024 bytes, making the maximum message size 996 bytes. The Linux server's CREATE_SESSION operation checks that the size of callback Calls can be as large as 1044 bytes, to accommodate RPCSEC_GSS. Thus CREATE_SESSION fails if a client advertises the true message size maximum of 996 bytes. But the server's backchannel currently does not support RPCSEC_GSS. The actual maximum size it needs is much smaller. It is safe to reduce the limit to enable NFSv4.1 on RDMA backchannel operation. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/auth.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/sunrpc/auth.h') diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h index 1ecf13e148b8..6a241a277249 100644 --- a/include/linux/sunrpc/auth.h +++ b/include/linux/sunrpc/auth.h @@ -20,11 +20,18 @@ #include #include +/* + * Maximum size of AUTH_NONE authentication information, in XDR words. + */ +#define NUL_CALLSLACK (4) +#define NUL_REPLYSLACK (2) + /* * Size of the nodename buffer. RFC1831 specifies a hard limit of 255 bytes, * but Linux hostnames are actually limited to __NEW_UTS_LEN bytes. */ #define UNX_MAXNODENAME __NEW_UTS_LEN +#define UNX_CALLSLACK (21 + XDR_QUADLEN(UNX_MAXNODENAME)) struct rpcsec_gss_info; -- cgit v1.2.3