leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

SUNRPC: Unset RPC_TASK_NO_RETRANS_TIMEOUT for NULL RPCs

Browse Source 
In some rare failure modes, the server is actually reading the
transport, but then just dropping the requests on the floor.
TCP_USER_TIMEOUT cannot detect that case.

Prevent such a stuck server from pinning client resources
indefinitely by ensuring that certain idempotent requests
(such as NULL) can time out even if the connection is still
operational.

Otherwise rpc_bind_new_program(), gss_destroy_cred(), or
rpc_clnt_test_and_add_xprt() can wait forever.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever 2021-07-19 10:48:10 -04:00 committed by Anna Schumaker
parent aede517207
commit 823c73d0c5
1 changed files with 14 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
net/sunrpc/clnt.c
View File

@ -2694,6 +2694,18 @@ static const struct rpc_procinfo rpcproc_null = {
.p_decode = rpcproc_decode_null,
};
static void
rpc_null_call_prepare(struct rpc_task *task, void *data)
{
task->tk_flags &= ~RPC_TASK_NO_RETRANS_TIMEOUT;
rpc_call_start(task);
}
static const struct rpc_call_ops rpc_null_ops = {
.rpc_call_prepare = rpc_null_call_prepare,
.rpc_call_done = rpc_default_callback,
};
static
struct rpc_task *rpc_call_null_helper(struct rpc_clnt *clnt,
struct rpc_xprt *xprt, struct rpc_cred *cred, int flags,
@ -2707,7 +2719,7 @@ struct rpc_task *rpc_call_null_helper(struct rpc_clnt *clnt,
.rpc_xprt = xprt,
.rpc_message = &msg,
.rpc_op_cred = cred,
.callback_ops = (ops != NULL) ? ops : &rpc_default_ops,
.callback_ops = ops ?: &rpc_null_ops,
.callback_data = data,
.flags = flags | RPC_TASK_SOFT | RPC_TASK_SOFTCONN |
RPC_TASK_NULLCREDS,
@ -2758,6 +2770,7 @@ static void rpc_cb_add_xprt_release(void *calldata)
}
static const struct rpc_call_ops rpc_cb_add_xprt_call_ops = {
.rpc_call_prepare = rpc_null_call_prepare,
.rpc_call_done = rpc_cb_add_xprt_done,
.rpc_release = rpc_cb_add_xprt_release,
};