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
..
acpi
asm-generic	mm: introduce mm_[p4d|pud|pmd]_folded	2018-12-29 13:37:58 +01:00
clocksource
crypto	crypto: speck - remove Speck	2018-11-13 11:08:46 -08:00
drm	drm: Get ref on CRTC commit object when waiting for flip_done	2018-10-18 14:23:13 -04:00
dt-bindings	ARM: SoC: late updates	2018-08-25 14:12:36 -07:00
keys
kvm
linux	SUNRPC: Always drop the XPRT_LOCK on XPRT_CLOSE_WAIT	2019-02-15 08:10:13 +01:00
math-emu
media	media: cec: keep track of outstanding transmits	2019-01-09 17:38:46 +01:00
memory
misc
net	ipvlan, l3mdev: fix broken l3s mode wrt local routes	2019-02-06 17:30:06 +01:00
pcmcia	pcmcia: remove long deprecated pcmcia_request_exclusive_irq() function	2018-08-18 12:30:42 -07:00
ras
rdma	IB/rxe: Revise the ib_wr_opcode enum	2018-11-13 11:08:43 -08:00
scsi
soc	soc: fsl: qbman: add APIs to retrieve the probing status	2018-09-27 15:43:35 -05:00
sound	ALSA: compress: Fix stop handling on compressed capture streams	2019-02-12 19:47:23 +01:00
target	scsi: target/core: Make sure that target_wait_for_sess_cmds() waits long enough	2019-01-26 09:32:38 +01:00
trace	sunrpc: use-after-free in svc_process_common()	2019-01-16 22:04:37 +01:00
uapi	Input: input_event - fix the CONFIG_SPARC64 mixup	2019-01-31 08:14:42 +01:00
video	fbdev changes for v4.19:	2018-08-23 15:44:58 -07:00
xen	Revert "xen/balloon: Mark unallocated host memory as UNUSABLE"	2018-12-17 09:24:39 +01:00