Benjamin Coddington 2440f3cebc SUNRPC: Always drop the XPRT_LOCK on XPRT_CLOSE_WAIT ... This patch is only appropriate for stable kernels v4.16 - v4.19 Since commit 9b30889c54 ("SUNRPC: Ensure we always close the socket after a connection shuts down"), and until commit c544577dad ("SUNRPC: Clean up transport write space handling"), it is possible for the NFS client to spin in the following tight loop: 269.964083: rpc_task_run_action: task:43@0 flags=5a81 state=0005 status=0 action=call_bind [sunrpc] 269.964083: rpc_task_run_action: task:43@0 flags=5a81 state=0005 status=0 action=call_connect [sunrpc] 269.964083: rpc_task_run_action: task:43@0 flags=5a81 state=0005 status=0 action=call_transmit [sunrpc] 269.964085: xprt_transmit: peer=[10.0.1.82]:2049 xid=0x761d3f77 status=-32 269.964085: rpc_task_run_action: task:43@0 flags=5a81 state=0005 status=-32 action=call_transmit_status [sunrpc] 269.964085: rpc_task_run_action: task:43@0 flags=5a81 state=0005 status=-32 action=call_status [sunrpc] 269.964085: rpc_call_status: task:43@0 status=-32 The issue is that the path through call_transmit_status does not release the XPRT_LOCK when the transmit result is -EPIPE, so the socket cannot be properly shut down. The below commit fixed things up in mainline by unconditionally calling xprt_end_transmit() and releasing the XPRT_LOCK after every pass through call_transmit. However, the entirety of this commit is not appropriate for stable kernels because its original inclusion was part of a series that modifies the sunrpc code to use a different queueing model. As a result, there are machinations within this patch that are not needed for a stable fix and will not make sense without a larger backport of the mainline series. In this patch, we take the slightly modified bit of the mainline patch below, which is to release the XPRT_LOCK on transmission error should we detect that the transport is waiting to close. commit c544577dad upstream Author: Trond Myklebust <trond.myklebust@hammerspace.com> Date: Mon Sep 3 23:39:27 2018 -0400 SUNRPC: Clean up transport write space handling Treat socket write space handling in the same way we now treat transport congestion: by denying the XPRT_LOCK until the transport signals that it has free buffer space. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> The original discussion of the problem is here: https://lore.kernel.org/linux-nfs/20181212135157.4489-1-dwysocha@redhat.com/T/#t This passes my usual cthon and xfstests on NFS as applied on v4.19 mainline. Reported-by: Dave Wysochanski <dwysocha@redhat.com> Suggested-by: Trond Myklebust <trondmy@hammerspace.com> Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2019-02-15 08:10:13 +01:00
..
addr.h
auth.h	net/sunrpc: Make rpc_auth_create_args a const	2018-07-30 13:19:41 -04:00
auth_gss.h
bc_xprt.h
cache.h
clnt.h	NFSv4 client live hangs after live data migration recovery	2018-07-31 12:53:40 -04:00
debug.h
gss_api.h
gss_asn1.h
gss_err.h
gss_krb5.h
gss_krb5_enctypes.h
metrics.h	sunrpc: Change rpc_print_iostats to rpc_clnt_show_stats and handle rpc_clnt clones	2018-07-31 12:53:35 -04:00
msg_prot.h
rpc_pipe_fs.h	remove rpc_rmdir()	2018-04-16 14:20:26 -04:00
rpc_rdma.h	xprtrdma: Add proper SPDX tags for NetApp-contributed source	2018-05-07 09:20:03 -04:00
sched.h
stats.h
svc.h	sunrpc: use-after-free in svc_process_common()	2019-01-16 22:04:37 +01:00
svc_rdma.h	svcrdma: Remove unused svc_rdma_op_ctxt	2018-05-11 15:48:57 -04:00
svc_xprt.h
svcauth.h	sunrpc: Extract target name into svc_cred	2018-08-22 18:32:07 -04:00
svcauth_gss.h
svcsock.h
timer.h
types.h
xdr.h	NFSv4; Clean up XDR encoding of type bitmap4	2018-04-10 16:06:22 -04:00
xprt.h	SUNRPC: Always drop the XPRT_LOCK on XPRT_CLOSE_WAIT	2019-02-15 08:10:13 +01:00
xprtmultipath.h
xprtrdma.h	xprtrdma: Add proper SPDX tags for NetApp-contributed source	2018-05-07 09:20:03 -04:00
xprtsock.h