After commit a11a2bf4, "SUNRPC: Optimise away unnecessary data moves in xdr_align_pages", Thu Aug 2 13:21:43 2012, READs larger than a few hundred bytes via NFS/RDMA no longer work. This commit exposed a long-standing bug in rpcrdma_inline_fixup().
I reproduce this with an rsize=4096 mount using the cthon04 basic tests. Test 5 fails with an EIO error. For my reproducer, kernel log shows: NFS: server cheating in read reply: count 4096 > recvd 0 rpcrdma_inline_fixup() is zeroing the xdr_stream::page_len field, and xdr_align_pages() is now returning that value to the READ XDR decoder function. That field is set up by xdr_inline_pages() by the READ XDR encoder function. As far as I can tell, it is supposed to be left alone after that, as it describes the dimensions of the reply xdr_stream, not the contents of that stream. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=68391 Signed-off-by: Chuck Lever <[email protected]> Cc: <[email protected]> # 3.7+ --- net/sunrpc/xprtrdma/rpc_rdma.c | 4 +--- 1 files changed, 1 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index e03725b..96ead52 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -649,9 +649,7 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad) break; page_base = 0; } - rqst->rq_rcv_buf.page_len = olen - copy_len; - } else - rqst->rq_rcv_buf.page_len = 0; + } if (copy_len && rqst->rq_rcv_buf.tail[0].iov_len) { curlen = copy_len; -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
