Commit graph

530 commits

Author SHA1 Message Date
Dai Ngo
43d48cec9a SUNRPC: remove the maximum number of retries in call_bind_status
[ Upstream commit 691d0b7820 ]

Currently call_bind_status places a hard limit of 3 to the number of
retries on EACCES error. This limit was done to prevent NLM unlock
requests from being hang forever when the server keeps returning garbage.
However this change causes problem for cases when NLM service takes
longer than 9 seconds to register with the port mapper after a restart.

This patch removes this hard coded limit and let the RPC handles
the retry based on the standard hard/soft task semantics.

Fixes: 0b760113a3 ("NLM: Don't hang forever on NLM unlock requests")
Reported-by: Helen Chao <helen.chao@oracle.com>
Tested-by: Helen Chao <helen.chao@oracle.com>
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-05-11 23:03:35 +09:00
NeilBrown
f859788868 NFS: fix disabling of swap
[ Upstream commit 5bab56fff5 ]

When swap is activated to a file on an NFSv4 mount we arrange that the
state manager thread is always present as starting a new thread requires
memory allocations that might block waiting for swap.

Unfortunately the code for allowing the state manager thread to exit when
swap is disabled was not tested properly and does not work.
This can be seen by examining /proc/fs/nfsfs/servers after disabling swap
and unmounting the filesystem.  The servers file will still list one
entry.  Also a "ps" listing will show the state manager thread is still
present.

There are two problems.
 1/ rpc_clnt_swap_deactivate() doesn't walk up the ->cl_parent list to
    find the primary client on which the state manager runs.

 2/ The thread is not woken up properly and it immediately goes back to
    sleep without checking whether it is really needed.  Using
    nfs4_schedule_state_manager() ensures a proper wake-up.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 4dc73c6791 ("NFSv4: keep state manager thread active if swap is enabled")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10 09:33:22 +01:00
Wang ShaoBo
05acc401bc SUNRPC: Fix missing release socket in rpc_sockname()
[ Upstream commit 50fa355bc0 ]

socket dynamically created is not released when getting an unintended
address family type in rpc_sockname(), direct to out_release for calling
sock_release().

Fixes: 2e738fdce2 ("SUNRPC: Add API to acquire source address")
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:32:23 +01:00
Trond Myklebust
dc4c430485 SUNRPC: Add API to force the client to disconnect
Allow the caller to force a disconnection of the RPC client so that we
can clear any pending requests that are buffered in the socket.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-10-06 09:52:09 -04:00
Trond Myklebust
f8423909ec SUNRPC: Add a helper to allow pNFS drivers to selectively cancel RPC calls
Add the helper rpc_cancel_tasks(), which uses a caller-defined selection
function to define a set of in-flight RPC calls to cancel. This is
mainly intended for pNFS drivers which are subject to a layout recall,
and which may therefore want to cancel all pending I/O using that layout
in order to redrive it after the layout recall has been satisfied.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-10-06 09:52:09 -04:00
Trond Myklebust
39494194f9 SUNRPC: Fix races with rpc_killall_tasks()
Ensure that we immediately call rpc_exit_task() after waking up, and
that the tk_rpc_status cannot get clobbered by some other function.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-10-06 09:52:09 -04:00
Bo Liu
9947e57b22 SUNRPC: Directly use ida_alloc()/free()
Use ida_alloc()/ida_free() instead of
ida_simple_get()/ida_simple_remove().
The latter is deprecated and more verbose.

Signed-off-by: Bo Liu <liubo03@inspur.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-10-03 11:26:36 -04:00
Dan Aloni
13bd901418 Revert "SUNRPC: Remove unreachable error condition"
This reverts commit efe57fd58e.

The assumption that it is impossible to return an ERR pointer from
rpc_run_task() no longer holds due to commit 25cf32ad5d ("SUNRPC:
Handle allocation failure in rpc_new_task()").

Fixes: 25cf32ad5d ('SUNRPC: Handle allocation failure in rpc_new_task()')
Fixes: efe57fd58e ('SUNRPC: Remove unreachable error condition')
Signed-off-by: Dan Aloni <dan.aloni@vastdata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-09-08 11:11:23 -04:00
Trond Myklebust
ed06fce0b0 SUNRPC: RPC level errors should set task->tk_rpc_status
Fix up a case in call_encode() where we're failing to set
task->tk_rpc_status when an RPC level error occurred.

Fixes: 9c5948c248 ("SUNRPC: task should be exit if encode return EKEYEXPIRED more times")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-08-19 20:32:05 -04:00
Trond Myklebust
72691a269f SUNRPC: Don't reuse bvec on retransmission of the request
If a request is re-encoded and then retransmitted, we need to make sure
that we also re-encode the bvec, in case the page lists have changed.

Fixes: ff053dbbaf ("SUNRPC: Move the call to xprt_send_pagedata() out of xprt_sock_sendmsg()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-27 16:26:17 -04:00
Olga Kornievskaia
92cc04f60a SUNRPC create a function that probes only offline transports
For only offline transports, attempt to check connectivity via
a NULL call and, if that succeeds, call a provided session trunking
detection function.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-25 10:06:04 -04:00
Olga Kornievskaia
7960aa9e4d SUNRPC restructure rpc_clnt_setup_test_and_add_xprt
In preparation for code re-use, pull out the part of the
rpc_clnt_setup_test_and_add_xprt() portion that sends a NULL rpc
and then calls a session trunking function into a helper function.

Re-organize the end of the function for code re-use.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-25 10:06:04 -04:00
Olga Kornievskaia
497e6464d6 SUNRPC create an rpc function that allows xprt removal from rpc_clnt
Expose a function that allows a removal of xprt from the rpc_clnt.

When called from NFS that's running a trunked transport then don't
decrement the active transport counter.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-25 10:06:04 -04:00
Olga Kornievskaia
9368fd6c75 SUNRPC enable back offline transports in trunking discovery
When we are adding a transport to a xprt_switch that's already on
the list but has been marked OFFLINE, then make the state ONLINE
since it's been tested now.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-25 10:06:04 -04:00
Olga Kornievskaia
95d0d30c66 SUNRPC create an iterator to list only OFFLINE xprts
Create a new iterator helper that will go thru the all the transports
in the switch and return transports that are marked OFFLINE.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-25 10:06:04 -04:00
Olga Kornievskaia
895245ccea SUNRPC add function to offline remove trunkable transports
Iterate thru available transports in the xprt_switch for all
trunkable transports offline and possibly remote them as well.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-25 10:06:04 -04:00
Chuck Lever
0701214cd6 SUNRPC: Fail faster on bad verifier
A bad verifier is not a garbage argument, it's an authentication
failure. Retrying it doesn't make the problem go away, and delays
upper layer recovery steps.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-07-23 15:34:34 -04:00
Scott Mayhew
304791255a sunrpc: set cl_max_connect when cloning an rpc_clnt
If the initial attempt at trunking detection using the krb5i auth flavor
fails with -EACCES, -NFS4ERR_CLID_INUSE, or -NFS4ERR_WRONGSEC, then the
NFS client tries again using auth_sys, cloning the rpc_clnt in the
process.  If this second attempt at trunking detection succeeds, then
the resulting nfs_client->cl_rpcclient winds up having cl_max_connect=0
and subsequent attempts to add additional transport connections to the
rpc_clnt will fail with a message similar to the following being logged:

[502044.312640] SUNRPC: reached max allowed number (0) did not add
transport to server: 192.168.122.3

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fixes: dc48e0abee ("SUNRPC enforce creation of no more than max_connect xprts")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-06-07 10:36:33 -04:00
Trond Myklebust
fd13359f54 SUNRPC: Ensure that the gssproxy client can start in a connected state
Ensure that the gssproxy client connects to the server from the gssproxy
daemon process context so that the AF_LOCAL socket connection is done
using the correct path and namespaces.

Fixes: 1d658336b0 ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-05-07 14:31:15 -04:00
Trond Myklebust
3d1b0d3514 Revert "SUNRPC: Ensure gss-proxy connects on setup"
This reverts commit 892de36fd4.

The gssproxy server is unresponsive when it calls into the kernel to
start the upcall service, so it will not reply to our RPC ping at all.

Reported-by: "J.Bruce Fields" <bfields@fieldses.org>
Fixes: 892de36fd4 ("SUNRPC: Ensure gss-proxy connects on setup")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-05-07 14:30:40 -04:00
Trond Myklebust
892de36fd4 SUNRPC: Ensure gss-proxy connects on setup
For reasons best known to the author, gss-proxy does not implement a
NULL procedure, and returns RPC_PROC_UNAVAIL. However we still want to
ensure that we connect to the service at setup time.
So add a quirk-flag specially for this case.

Fixes: 1d658336b0 ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-04-29 12:29:31 -04:00
Olga Kornievskaia
e13433b441 SUNRPC release the transport of a relocated task with an assigned transport
A relocated task must release its previous transport.

Fixes: 82ee41b85c ("SUNRPC don't resend a task on an offlined transport")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-04-22 11:11:31 -04:00
Trond Myklebust
25cf32ad5d SUNRPC: Handle allocation failure in rpc_new_task()
If the call to rpc_alloc_task() fails, then ensure that the calldata is
released, and that rpc_run_task() and rpc_run_bc_task() bail out early.

Reported-by: NeilBrown <neilb@suse.de>
Fixes: 910ad38697 ("NFS: Fix memory allocation in rpc_alloc_task()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-04-07 16:20:00 -04:00
Trond Myklebust
9d82819d5b SUNRPC: Handle low memory situations in call_status()
We need to handle ENFILE, ENOBUFS, and ENOMEM, because
xprt_wake_pending_tasks() can be called with any one of these due to
socket creation failures.

Fixes: b61d59fffd ("SUNRPC: xs_tcp_connect_worker{4,6}: merge common code")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-04-07 16:20:00 -04:00
Trond Myklebust
d3c15033b2 SUNRPC: Handle ENOMEM in call_transmit_status()
Both call_transmit() and call_bc_transmit() can now return ENOMEM, so
let's make sure that we handle the errors gracefully.

Fixes: 0472e47660 ("SUNRPC: Convert socket page send code to use iov_iter()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-04-07 16:20:00 -04:00
NeilBrown
eb07d5a4da SUNRPC: handle malloc failure in ->request_prepare
If ->request_prepare() detects an error, it sets ->rq_task->tk_status.
This is easy for callers to ignore.
The only caller is xprt_request_enqueue_receive() and it does ignore the
error, as does call_encode() which calls it.  This can result in a
request being queued to receive a reply without an allocated receive buffer.

So instead of setting rq_task->tk_status, return an error, and store in
->tk_status only in call_encode();

The call to xprt_request_enqueue_receive() is now earlier in
call_encode(), where the error can still be handled.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-29 22:15:46 -04:00
Olga Kornievskaia
82ee41b85c SUNRPC don't resend a task on an offlined transport
When a task is being retried, due to an NFS error, if the assigned
transport has been put offline and the task is relocatable pick a new
transport.

Fixes: 6f081693e7 ("sunrpc: remove an offlined xprt using sysfs")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-24 12:06:07 -04:00
NeilBrown
4dc73c6791 NFSv4: keep state manager thread active if swap is enabled
If we are swapping over NFSv4, we may not be able to allocate memory to
start the state-manager thread at the time when we need it.
So keep it always running when swap is enabled, and just signal it to
start.

This requires updating and testing the cl_swapper count on the root
rpc_clnt after following all ->cl_parent links.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-13 12:59:35 -04:00
NeilBrown
8db55a032a SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC
rpc tasks can be marked as RPC_TASK_SWAPPER.  This causes GFP_MEMALLOC
to be used for some allocations.  This is needed in some cases, but not
in all where it is currently provided, and in some where it isn't
provided.

Currently *all* tasks associated with a rpc_client on which swap is
enabled get the flag and hence some GFP_MEMALLOC support.

GFP_MEMALLOC is provided for ->buf_alloc() but only swap-writes need it.
However xdr_alloc_bvec does not get GFP_MEMALLOC - though it often does
need it.

xdr_alloc_bvec is called while the XPRT_LOCK is held.  If this blocks,
then it blocks all other queued tasks.  So this allocation needs
GFP_MEMALLOC for *all* requests, not just writes, when the xprt is used
for any swap writes.

Similarly, if the transport is not connected, that will block all
requests including swap writes, so memory allocations should get
GFP_MEMALLOC if swap writes are possible.

So with this patch:
 1/ we ONLY set RPC_TASK_SWAPPER for swap writes.
 2/ __rpc_execute() sets PF_MEMALLOC while handling any task
    with RPC_TASK_SWAPPER set, or when handling any task that
    holds the XPRT_LOCKED lock on an xprt used for swap.
    This removes the need for the RPC_IS_SWAPPER() test
    in ->buf_alloc handlers.
 3/ xprt_prepare_transmit() sets PF_MEMALLOC after locking
    any task to a swapper xprt.  __rpc_execute() will clear it.
 3/ PF_MEMALLOC is set for all the connect workers.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com> (for xprtrdma parts)
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-13 12:59:35 -04:00
NeilBrown
a41b05edfe SUNRPC/auth: async tasks mustn't block waiting for memory
When memory is short, new worker threads cannot be created and we depend
on the minimum one rpciod thread to be able to handle everything.  So it
must not block waiting for memory.

mempools are particularly a problem as memory can only be released back
to the mempool by an async rpc task running.  If all available workqueue
threads are waiting on the mempool, no thread is available to return
anything.

lookup_cred() can block on a mempool or kmalloc - and this can cause
deadlocks.  So add a new RPCAUTH_LOOKUP flag for async lookups and don't
block on memory.  If the -ENOMEM gets back to call_refreshresult(), wait
a short while and try again.  HZ>>4 is chosen as it is used elsewhere
for -ENOMEM retries.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-03-13 12:59:35 -04:00
Trond Myklebust
0adc879406 SUNRPC: Convert GFP_NOFS to GFP_KERNEL
The sections which should not re-enter the filesystem are already
protected with memalloc_nofs_save/restore calls, so it is better to use
GFP_KERNEL in these calls to allow better performance for synchronous
RPC calls.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-02-25 18:50:12 -05:00
Olga Kornievskaia
b8a09619a5 SUNRPC allow for unspecified transport time in rpc_clnt_add_xprt
If the supplied argument doesn't specify the transport type, use the
type of the existing rpc clnt and its existing transport.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2022-01-13 09:36:58 -05:00
Thiago Rafael Becker
023859ce6f sunrpc: remove unnecessary test in rpc_task_set_client()
In rpc_task_set_client(), testing for a NULL clnt is not necessary, as
clnt should always be a valid pointer to a rpc_client.

Signed-off-by: Thiago Rafael Becker <trbecker@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-10-20 18:09:55 -04:00
Olga Kornievskaia
dc48e0abee SUNRPC enforce creation of no more than max_connect xprts
If we are adding new transports via rpc_clnt_test_and_add_xprt()
then check if we've reached the limit. Currently only pnfs path
adds transports via that function but this is done in
preparation when the client would add new transports when
session trunking is detected. A warning is logged if the
limit is reached.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-27 16:37:29 -04:00
Olga Kornievskaia
3a3f976639 SUNRPC keep track of number of transports to unique addresses
Currently, xprt_switch keeps a number of all xprts (xps_nxprts)
that were added to the switch regardless of whethere it's an
nconnect transport or a transport to a trunkable address.
Introduce a new counter to keep track of transports to unique
destination addresses per xprt_switch.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-27 16:36:53 -04:00
Trond Myklebust
71d3d0ebc8 SUNRPC: Convert rpc_client refcount to use refcount_t
There are now tools in the refcount library that allow us to convert the
client shutdown code.

Reported-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-09 16:57:04 -04:00
Chuck Lever
823c73d0c5 SUNRPC: Unset RPC_TASK_NO_RETRANS_TIMEOUT for NULL RPCs
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>
2021-08-09 16:32:27 -04:00
Chuck Lever
aede517207 SUNRPC: Refactor rpc_ping()
Make it use the rpc_null_call_helper() so that it can share the
new rpc_call_ops structure to be introduced in the next patch.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-09 16:32:27 -04:00
Olga Kornievskaia
6f081693e7 sunrpc: remove an offlined xprt using sysfs
Once a transport has been put offline, this transport can be also
removed from the list of transports. Any tasks that have been stuck
on this transport would find the next available active transport
and be re-tried. This transport would be removed from the xprt_switch
list and freed.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-07-08 14:03:24 -04:00
Olga Kornievskaia
e091853ebd SUNRPC mark the first transport
When an RPC client gets created it's first transport is special
and should be marked a main transport.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-07-08 14:03:24 -04:00
Olga Kornievskaia
2a338a5431 sunrpc: add a symlink from rpc-client directory to the xprt_switch
An rpc client uses a transport switch and one ore more transports
associated with that switch. Since transports are shared among
rpc clients, create a symlink into the xprt_switch directory
instead of duplicating entries under each rpc client.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-07-08 14:03:23 -04:00
Olga Kornievskaia
c5a382ebdb sunrpc: Create per-rpc_clnt sysfs kobjects
These will eventually have files placed under them for sysfs operations.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-07-08 14:03:23 -04:00
NeilBrown
e877a88d1f SUNRPC in case of backlog, hand free slots directly to waiting task
If sunrpc.tcp_max_slot_table_entries is small and there are tasks
on the backlog queue, then when a request completes it is freed and the
first task on the queue is woken.  The expectation is that it will wake
and claim that request.  However if it was a sync task and the waiting
process was killed at just that moment, it will wake and NOT claim the
request.

As long as TASK_CONGESTED remains set, requests can only be claimed by
tasks woken from the backlog, and they are woken only as requests are
freed, so when a task doesn't claim a request, no other task can ever
get that request until TASK_CONGESTED is cleared.  Each time this
happens the number of available requests is decreased by one.

With a sufficiently high workload and sufficiently low setting of
max_slot (16 in the case where this was seen), TASK_CONGESTED can remain
set for an extended period, and the above scenario (of a process being
killed just as its task was woken) can repeat until no requests can be
allocated.  Then traffic stops.

This patch addresses the problem by introducing a positive handover of a
request from a completing task to a backlog task - the request is never
freed when there is a backlog.

When a task is woken it might not already have a request attached in
which case it is *not* freed (as with current code) but is initialised
(if needed) and used.  If it isn't used it will eventually be freed by
rpc_exit_task().  xprt_release() is enhanced to be able to correctly
release an uninitialised request.

Fixes: ba60eb25ff ("SUNRPC: Fix a livelock problem in the xprt->backlog queue")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-05-20 12:17:08 -04:00
Baptiste Lepers
f8f7e0fb22 sunrpc: Fix misplaced barrier in call_decode
Fix a misplaced barrier in call_decode. The struct rpc_rqst is modified
as follows by xprt_complete_rqst:

req->rq_private_buf.len = copied;
/* Ensure all writes are done before we update */
/* req->rq_reply_bytes_recvd */
smp_wmb();
req->rq_reply_bytes_recvd = copied;

And currently read as follows by call_decode:

smp_rmb(); // misplaced
if (!req->rq_reply_bytes_recvd)
   goto out;
req->rq_rcv_buf.len = req->rq_private_buf.len;

This patch places the smp_rmb after the if to ensure that
rq_reply_bytes_recvd and rq_private_buf.len are read in order.

Fixes: 9ba828861c ("SUNRPC: Don't try to parse incomplete RPC messages")
Signed-off-by: Baptiste Lepers <baptiste.lepers@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-05-01 19:42:14 -04:00
Chuck Lever
7638e0bfae SUNRPC: Move fault injection call sites
I've hit some crashes that occur in the xprt_rdma_inject_disconnect
path. It appears that, for some provides, rdma_disconnect() can
take so long that the transport can disconnect and release its
hardware resources while rdma_disconnect() is still running,
resulting in a UAF in the provider.

The transport's fault injection method may depend on the stability
of transport data structures. That means it needs to be invoked
only from contexts that hold the transport write lock.

Fixes: 4a06825839 ("SUNRPC: Transport fault injection")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-14 09:36:29 -04:00
Trond Myklebust
9ed5af268e SUNRPC: Clean up the handling of page padding in rpc_prepare_reply_pages()
rpc_prepare_reply_pages() currently expects the 'hdrsize' argument to
contain the length of the data that we expect to want placed in the head
kvec plus a count of 1 word of padding that is placed after the page data.
This is very confusing when trying to read the code, and sometimes leads
to callers adding an arbitrary value of '1' just in order to satisfy the
requirement (whether or not the page data actually needs such padding).

This patch aims to clarify the code by changing the 'hdrsize' argument
to remove that 1 word of padding. This means we need to subtract the
padding from all the existing callers.

Fixes: 02ef04e432 ("NFS: Account for XDR pad of buf->pages")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-12-02 14:05:53 -05:00
Chuck Lever
42ebfc2cbf SUNRPC: Clean up call_bind_status() observability
Time to remove dprintk call sites in here.

Regarding the rpc_bind_status tracepoint: It's friendlier to
administrators if they don't have to look up the error code to
figure out what went wrong. Replace trace_rpc_bind_status with a
set of tracepoints that report more specifically what the problem
was, and what RPC program/version was being queried.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:09 -04:00
Chuck Lever
fd66e2a79d SUNRPC: Remove dprintk call site in call_decode
Clean up.

When enabled, this dprintk adds a line in /var/log/messages after
every RPC that reports the task ID (no connection to on the wire
XID values) and the RPC's result (no connection to the program,
operation, or the arguments and results).

Thus it's value is pretty low. Let's remove it.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:09 -04:00
Chuck Lever
7c8099f6ad SUNRPC: Trace call_refresh events
Clean up: Replace dprintk call sites.

Note that rpc_call_rpcerror() already has a trace point, so perhaps
adding trace_rpc_refresh_status() isn't necessary. However, it does
report a particular category of error.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:09 -04:00
Chuck Lever
914cdcc78a SUNRPC: Add trace_rpc_timeout_status()
For a long while we've wanted a tracepoint that fires when a major
timeout is reported in the system log. Such a tracepoint can be
attached to other actions that can take place when a timeout is
detected (eg, server or connection health assessment).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-21 10:21:09 -04:00