This is a note to let you know that I've just added the patch titled NFSv4.1: fix handling of backchannel binding in BIND_CONN_TO_SESSION to the 5.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nfsv4.1-fix-handling-of-backchannel-binding-in-bind_conn_to_session.patch and it can be found in the queue-5.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From dff58530c4ca8ce7ee5a74db431c6e35362cf682 Mon Sep 17 00:00:00 2001 From: Olga Kornievskaia <olga.kornievskaia@xxxxxxxxx> Date: Fri, 24 Apr 2020 17:45:50 -0400 Subject: NFSv4.1: fix handling of backchannel binding in BIND_CONN_TO_SESSION From: Olga Kornievskaia <olga.kornievskaia@xxxxxxxxx> commit dff58530c4ca8ce7ee5a74db431c6e35362cf682 upstream. Currently, if the client sends BIND_CONN_TO_SESSION with NFS4_CDFC4_FORE_OR_BOTH but only gets NFS4_CDFS4_FORE back it ignores that it wasn't able to enable a backchannel. To make sure, the client sends BIND_CONN_TO_SESSION as the first operation on the connections (ie., no other session compounds haven't been sent before), and if the client's request to bind the backchannel is not satisfied, then reset the connection and retry. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/nfs/nfs4proc.c | 8 ++++++++ include/linux/nfs_xdr.h | 2 ++ include/linux/sunrpc/clnt.h | 5 +++++ 3 files changed, 15 insertions(+) --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -7893,6 +7893,7 @@ static void nfs4_bind_one_conn_to_session_done(struct rpc_task *task, void *calldata) { struct nfs41_bind_conn_to_session_args *args = task->tk_msg.rpc_argp; + struct nfs41_bind_conn_to_session_res *res = task->tk_msg.rpc_resp; struct nfs_client *clp = args->client; switch (task->tk_status) { @@ -7901,6 +7902,12 @@ nfs4_bind_one_conn_to_session_done(struc nfs4_schedule_session_recovery(clp->cl_session, task->tk_status); } + if (args->dir == NFS4_CDFC4_FORE_OR_BOTH && + res->dir != NFS4_CDFS4_BOTH) { + rpc_task_close_connection(task); + if (args->retries++ < MAX_BIND_CONN_TO_SESSION_RETRIES) + rpc_restart_call(task); + } } static const struct rpc_call_ops nfs4_bind_one_conn_to_session_ops = { @@ -7923,6 +7930,7 @@ int nfs4_proc_bind_one_conn_to_session(s struct nfs41_bind_conn_to_session_args args = { .client = clp, .dir = NFS4_CDFC4_FORE_OR_BOTH, + .retries = 0, }; struct nfs41_bind_conn_to_session_res res; struct rpc_message msg = { --- a/include/linux/nfs_xdr.h +++ b/include/linux/nfs_xdr.h @@ -1307,11 +1307,13 @@ struct nfs41_impl_id { struct nfstime4 date; }; +#define MAX_BIND_CONN_TO_SESSION_RETRIES 3 struct nfs41_bind_conn_to_session_args { struct nfs_client *client; struct nfs4_sessionid sessionid; u32 dir; bool use_conn_in_rdma_mode; + int retries; }; struct nfs41_bind_conn_to_session_res { --- a/include/linux/sunrpc/clnt.h +++ b/include/linux/sunrpc/clnt.h @@ -236,4 +236,9 @@ static inline int rpc_reply_expected(str (task->tk_msg.rpc_proc->p_decode != NULL); } +static inline void rpc_task_close_connection(struct rpc_task *task) +{ + if (task->tk_xprt) + xprt_force_disconnect(task->tk_xprt); +} #endif /* _LINUX_SUNRPC_CLNT_H */ Patches currently in stable-queue which might be from olga.kornievskaia@xxxxxxxxx are queue-5.6/nfsv4.1-fix-handling-of-backchannel-binding-in-bind_conn_to_session.patch