These need further refinement, but I'm posting now to spark some
discussion.
To address manifold reports of svc_unregister() hanging (either at
shutdown or if rpcbind simply wasn't ever started), these patches add
a new per-request soft connect semantic, and update the kernel's
rpcbind client to use a connection-oriented transport for local
queries. This should cause the kernel's local rpcbind queries to fail
immediately if rpcbind isn't reachable.
This can work with either TCP or connected UDP. I used TCP here
merely as an example.
The final two patches have not been tested, but provide a taste of
other uses for the soft connect semantic. One possible use is to
address Ian's NFSv4 mount hang problems by making rpc_ping() fail if
it cannot connect to the server.
We can also make use of this new feature to do proper "hangless" NFS
v2/v3 version and transport negotiation in the kernel, although
that is beyond the scope of the current patch set.
---
Chuck Lever (7):
SUNRPC: Use soft connect semantics when performing RPC ping
SUNRPC: Use soft connects for autobinding over TCP
SUNRPC: Use TCP for local rpcbind upcalls
SUNRPC: maintain a single transport for rpcbind upcalls
SUNRPC: Clean up call_transmit_status()
SUNRPC: Allow RPCs to fail quickly if the server is unreachable
SUNRPC: Don't report a connect delay of 0 seconds
include/linux/sunrpc/sched.h | 2 +
net/sunrpc/clnt.c | 45 ++++++++++++++++++++--------
net/sunrpc/rpcb_clnt.c | 68 ++++++++++++++++++++++++++++++++----------
net/sunrpc/sunrpc_syms.c | 5 +++
net/sunrpc/xprtsock.c | 9 +++---
5 files changed, 96 insertions(+), 33 deletions(-)
--
Chuck Lever <chuck.lever@xxxxxxxxxx>
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