Commit Graph

216 Commits

Author SHA1 Message Date
Chuck Lever
0dae72d581 sunrpc: Prevent duplicate XID allocation
Krzysztof Kozlowski <krzk@kernel.org> reports that a heavy NFSv4
WRITE workload against a slow NFS server causes his Raspberry Pi
clients to stall. Krzysztof bisected it to commit 37ac86c3a7
("SUNRPC: Initialize rpc_rqst outside of xprt->reserve_lock") .

I was able to reproduce similar behavior and it appears that rarely
the RPC client layer is re-allocating an XID for an RPC that it has
already partially sent. This results in the client ignoring the
subsequent reply, which carries the original XID.

For various reasons, checking !req->rq_xmit_bytes_sent in
xprt_prepare_transmit is not a 100% reliable mechanism for
determining when a fresh XID is needed.

Trond's preference is to allocate the XID at the time each rpc_rqst
slot is initialized.

This patch should also address a gcc 4.1.2 complaint reported by
Geert Uytterhoeven <geert@linux-m68k.org>.

Reported-by: Krzysztof Kozlowski <krzk@kernel.org>
Fixes: 37ac86c3a7 ("SUNRPC: Initialize rpc_rqst outside of ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2018-06-19 08:53:48 -04:00
Chuck Lever
a9cde23ab7 SUNRPC: Add a ->free_slot transport callout
Refactor: xprtrdma needs to have better control over when RPCs are
awoken from the backlog queue, so replace xprt_free_slot with a
transport op callout.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-05-07 09:20:03 -04:00
Chuck Lever
37ac86c3a7 SUNRPC: Initialize rpc_rqst outside of xprt->reserve_lock
alloc_slot is a transport-specific op, but initializing an rpc_rqst
is common to all transports. In addition, the only part of initial-
izing an rpc_rqst that needs serialization is getting a fresh XID.

Move rpc_rqst initialization to common code in preparation for
adding a transport-specific alloc_slot to xprtrdma.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-05-07 09:20:03 -04:00
Chuck Lever
ff699ea826 SUNRPC: Make num_reqs a non-atomic integer
If recording xprt->stat.max_slots is moved into xprt_alloc_slot,
then xprt->num_reqs is never manipulated outside
xprt->reserve_lock. There's no longer a need for xprt->num_reqs to
be atomic.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-04-10 16:06:22 -04:00
Chuck Lever
78215759e2 SUNRPC: Make RTT measurement more precise (Send)
Some RPC transports have more overhead in their send_request
callouts than others. For example, for RPC-over-RDMA:

- Marshaling an RPC often has to DMA map the RPC arguments

- Registration methods perform memory registration as part of
  marshaling

To capture just server and network latencies more precisely: when
sending a Call, capture the rq_xtime timestamp _after_ the transport
header has been marshaled.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-04-10 16:06:22 -04:00
Chuck Lever
0b87a46b43 SUNRPC: Make RTT measurement more precise (Receive)
Some RPC transports have more overhead in their reply handlers
than others. For example, for RPC-over-RDMA:

- RPC completion has to wait for memory invalidation, which is
  not a part of the server/network round trip

- Recently a context switch was introduced into the reply handler,
  which further artificially inflates the measure of RPC RTT

To capture just server and network latencies more precisely: when
receiving a reply, compute the RTT as soon as the XID is recognized
rather than at RPC completion time.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-04-10 16:06:22 -04:00
Chuck Lever
ecd465ee88 SUNRPC: Move xprt_update_rtt callsite
Since commit 33849792cb ("xprtrdma: Detect unreachable NFS/RDMA
servers more reliably"), the xprtrdma transport now has a ->timer
callout. But xprtrdma does not need to compute RTT data, only UDP
needs that. Move the xprt_update_rtt call into the UDP transport
implementation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-04-10 16:06:22 -04:00
Trond Myklebust
2275cde4cc SUNRPC: Queue latency-sensitive socket tasks to xprtiod
The response to a write_space notification is very latency sensitive,
so we should queue it to the lower latency xprtiod_workqueue. This
is something we already do for the other cases where an rpc task
holds the transport XPRT_LOCKED bitlock.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2018-02-07 09:25:52 -05:00
Chuck Lever
82476d9f95 SUNRPC: Trace xprt_timer events
Track RPC timeouts: report the XID and the server address to match
the content of network capture.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-01-23 09:44:39 -05:00
Linus Torvalds
d025fbf1a2 NFS client fixes for Linux 4.15-rc4
Stable bugfixes:
 - NFS: Avoid a BUG_ON() in nfs_commit_inode() by not waiting for a
        commit in the case that there were no commit requests.
 - SUNRPC: Fix a race in the receive code path
 
 Other fixes:
 - NFS: Fix a deadlock in nfs client initialization
 - xprtrdma: Fix a performance regression for small IOs
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Merge tag 'nfs-for-4.15-3' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client fixes from Anna Schumaker:
 "This has two stable bugfixes, one to fix a BUG_ON() when
  nfs_commit_inode() is called with no outstanding commit requests and
  another to fix a race in the SUNRPC receive codepath.

  Additionally, there are also fixes for an NFS client deadlock and an
  xprtrdma performance regression.

  Summary:

  Stable bugfixes:
   - NFS: Avoid a BUG_ON() in nfs_commit_inode() by not waiting for a
     commit in the case that there were no commit requests.
   - SUNRPC: Fix a race in the receive code path

  Other fixes:
   - NFS: Fix a deadlock in nfs client initialization
   - xprtrdma: Fix a performance regression for small IOs"

* tag 'nfs-for-4.15-3' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  SUNRPC: Fix a race in the receive code path
  nfs: don't wait on commit in nfs_commit_inode() if there were no commit requests
  xprtrdma: Spread reply processing over more CPUs
  nfs: fix a deadlock in nfs client initialization
2017-12-16 13:12:53 -08:00
Trond Myklebust
90d91b0cd3 SUNRPC: Fix a race in the receive code path
We must ensure that the call to rpc_sleep_on() in xprt_transmit() cannot
race with the call to xprt_complete_rqst().

Reported-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=317
Fixes: ce7c252a8c ("SUNRPC: Add a separate spinlock to protect..")
Cc: stable@vger.kernel.org # 4.14+
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-12-15 14:31:56 -05:00
Linus Torvalds
c3e9c04b89 NFS client updates for Linux 4.15
Stable bugfixes:
 - Revalidate "." and ".." correctly on open
 - Avoid RCU usage in tracepoints
 - Fix ugly referral attributes
 - Fix a typo in nomigration mount option
 - Revert "NFS: Move the flock open mode check into nfs_flock()"
 
 Features:
 - Implement a stronger send queue accounting system for NFS over RDMA
 - Switch some atomics to the new refcount_t type
 
 Other bugfixes and cleanups:
 - Clean up access mode bits
 - Remove special-case revalidations in nfs_opendir()
 - Improve invalidating NFS over RDMA memory for async operations that time out
 - Handle NFS over RDMA replies with a worqueue
 - Handle NFS over RDMA sends with a workqueue
 - Fix up replaying interrupted requests
 - Remove dead NFS over RDMA definitions
 - Update NFS over RDMA copyright information
 - Be more consistent with bool initialization and comparisons
 - Mark expected switch fall throughs
 - Various sunrpc tracepoint cleanups
 - Fix various OPEN races
 - Fix a typo in nfs_rename()
 - Use common error handling code in nfs_lock_and_join_request()
 - Check that some structures are properly cleaned up during net_exit()
 - Remove net pointer from dprintk()s
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Merge tag 'nfs-for-4.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client updates from Anna Schumaker:
 "Stable bugfixes:
   - Revalidate "." and ".." correctly on open
   - Avoid RCU usage in tracepoints
   - Fix ugly referral attributes
   - Fix a typo in nomigration mount option
   - Revert "NFS: Move the flock open mode check into nfs_flock()"

  Features:
   - Implement a stronger send queue accounting system for NFS over RDMA
   - Switch some atomics to the new refcount_t type

  Other bugfixes and cleanups:
   - Clean up access mode bits
   - Remove special-case revalidations in nfs_opendir()
   - Improve invalidating NFS over RDMA memory for async operations that
     time out
   - Handle NFS over RDMA replies with a worqueue
   - Handle NFS over RDMA sends with a workqueue
   - Fix up replaying interrupted requests
   - Remove dead NFS over RDMA definitions
   - Update NFS over RDMA copyright information
   - Be more consistent with bool initialization and comparisons
   - Mark expected switch fall throughs
   - Various sunrpc tracepoint cleanups
   - Fix various OPEN races
   - Fix a typo in nfs_rename()
   - Use common error handling code in nfs_lock_and_join_request()
   - Check that some structures are properly cleaned up during
     net_exit()
   - Remove net pointer from dprintk()s"

* tag 'nfs-for-4.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (62 commits)
  NFS: Revert "NFS: Move the flock open mode check into nfs_flock()"
  NFS: Fix typo in nomigration mount option
  nfs: Fix ugly referral attributes
  NFS: super: mark expected switch fall-throughs
  sunrpc: remove net pointer from messages
  nfs: remove net pointer from messages
  sunrpc: exit_net cleanup check added
  nfs client: exit_net cleanup check added
  nfs/write: Use common error handling code in nfs_lock_and_join_requests()
  NFSv4: Replace closed stateids with the "invalid special stateid"
  NFSv4: nfs_set_open_stateid must not trigger state recovery for closed state
  NFSv4: Check the open stateid when searching for expired state
  NFSv4: Clean up nfs4_delegreturn_done
  NFSv4: cleanup nfs4_close_done
  NFSv4: Retry NFS4ERR_OLD_STATEID errors in layoutreturn
  pNFS: Retry NFS4ERR_OLD_STATEID errors in layoutreturn-on-close
  NFSv4: Don't try to CLOSE if the stateid 'other' field has changed
  NFSv4: Retry CLOSE and DELEGRETURN on NFS4ERR_OLD_STATEID.
  NFS: Fix a typo in nfs_rename()
  NFSv4: Fix open create exclusive when the server reboots
  ...
2017-11-17 14:18:00 -08:00
Gustavo A. R. Silva
e9d4763935 net: sunrpc: mark expected switch fall-throughs
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-11-17 16:43:44 -05:00
David S. Miller
e1ea2f9856 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Several conflicts here.

NFP driver bug fix adding nfp_netdev_is_nfp_repr() check to
nfp_fl_output() needed some adjustments because the code block is in
an else block now.

Parallel additions to net/pkt_cls.h and net/sch_generic.h

A bug fix in __tcp_retransmit_skb() conflicted with some of
the rbtree changes in net-next.

The tc action RCU callback fixes in 'net' had some overlap with some
of the recent tcf_block reworking.

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-30 21:09:24 +09:00
Trond Myklebust
528fd3547b SUNRPC: Destroy transport from the system workqueue
The transport may need to flush transport connect and receive tasks
that are running on rpciod. In order to do so safely, we need to
ensure that the caller of cancel_work_sync() etc is not itself
running on rpciod.
Do so by running the destroy task from the system workqueue.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2017-10-19 12:17:56 -04:00
Kees Cook
ff861c4d64 sunrpc: Convert timers to use timer_setup()
In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-18 12:40:27 +01:00
Trond Myklebust
4c625a974f SUNRPC: fix a list corruption issue in xprt_release()
We remove the request from the receive list before we call
xprt_wait_on_pinned_rqst(), and so we need to use list_del_init().
Otherwise, we will see list corruption when xprt_complete_rqst()
is called.

Reported-by: Emre Celebi <emre@primarydata.com>
Fixes: ce7c252a8c ("SUNRPC: Add a separate spinlock to protect...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2017-10-16 08:24:08 -04:00
Chuck Lever
9590d083c1 xprtrdma: Use xprt_pin_rqst in rpcrdma_reply_handler
Adopt the use of xprt_pin_rqst to eliminate contention between
Call-side users of rb_lock and the use of rb_lock in
rpcrdma_reply_handler.

This replaces the mechanism introduced in 431af645cf ("xprtrdma:
Fix client lock-up after application signal fires").

Use recv_lock to quickly find the completing rqst, pin it, then
drop the lock. At that point invalidation and pull-up of the Reply
XDR can be done. Both are often expensive operations.

Finally, take recv_lock again to signal completion to the RPC
layer. It also protects adjustment of "cwnd".

This greatly reduces the amount of time a lock is held by the
reply handler. Comparing lock_stat results shows a marked decrease
in contention on rb_lock and recv_lock.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[trond.myklebust@primarydata.com: Remove call to rpcrdma_buffer_put() from
   the "out_norqst:" path in rpcrdma_reply_handler.]
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2017-09-05 18:27:07 -04:00
Trond Myklebust
ce7c252a8c SUNRPC: Add a separate spinlock to protect the RPC request receive list
This further reduces contention with the transport_lock, and allows us
to convert to using a non-bh-safe spinlock, since the list is now never
accessed from a bh context.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2017-08-18 14:45:04 -04:00
Trond Myklebust
729749bb8d SUNRPC: Don't hold the transport lock across socket copy operations
Instead add a mechanism to ensure that the request doesn't disappear
from underneath us while copying from the socket. We do this by
preventing xprt_release() from freeing the XDR buffers until the
flag RPC_TASK_MSG_RECV has been cleared from the request.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
2017-08-16 15:10:15 -04:00
Trond Myklebust
92ea011f7c SUNRPC: Make slot allocation more reliable
In xprt_alloc_slot(), the spin lock is only needed to provide atomicity
between the atomic_add_unless() failure and the call to xprt_add_backlog().
We do not actually need to hold it across the memory allocation itself.

By dropping the lock, we can use a more resilient GFP_NOFS allocation,
just as we now do in the rest of the RPC client code.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-07-13 15:58:04 -04:00
Chuck Lever
e2a4f4fbef sunrpc: Export xprt_force_disconnect()
xprt_force_disconnect() is already invoked from the socket
transport. I want to invoke xprt_force_disconnect() from the
RPC-over-RDMA transport, which is a separate module from sunrpc.ko.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-04-25 16:12:16 -04:00
Chuck Lever
b977b644cc sunrpc: Allow xprt->ops->timer method to sleep
The transport lock is needed to protect the xprt_adjust_cwnd() call
in xs_udp_timer, but it is not necessary for accessing the
rq_reply_bytes_recvd or tk_status fields. It is correct to sublimate
the lock into UDP's xs_udp_timer method, where it is required.

The ->timer method has to take the transport lock if needed, but it
can now sleep safely, or even call back into the RPC scheduler.

This is more a clean-up than a fix, but the "issue" was introduced
by my transport switch patches back in 2005.

Fixes: 46c0ee8bc4 ("RPC: separate xprt_timer implementations")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2017-02-10 14:02:37 -05:00
NeilBrown
2c2ee6d20b sunrpc: Don't engage exponential backoff when connection attempt is rejected.
xs_connect() contains an exponential backoff mechanism so the repeated
connection attempts are delayed by longer and longer amounts.

This is appropriate when the connection failed due to a timeout, but
it not appropriate when a definitive "no" answer is received.  In such
cases, call_connect_status() imposes a minimum 3-second back-off, so
not having the exponetial back-off will never result in immediate
retries.

The current situation is a problem when the NFS server tries to
register with rpcbind but rpcbind isn't running.  All connection
attempts are made on the same "xprt" and as the connection is never
"closed", the exponential back delays successive attempts to register,
or de-register, different protocols.  This results in a multi-minute
delay with no benefit.

So, when call_connect_status() receives a definitive "no", use
xprt_conditional_disconnect() to cancel the previous connection attempt.
This will set XPRT_CLOSE_WAIT so that xprt->ops->close() calls xs_close()
which resets the reestablish_timeout.

To ensure xprt_conditional_disconnect() does the right thing, we
ensure that rq_connect_cookie is set before a connection attempt, and
allow xprt_conditional_disconnect() to complete even when the
transport is not fully connected.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-12-01 17:40:41 -05:00
Chuck Lever
3435c74aed SUNRPC: Generalize the RPC buffer release API
xprtrdma needs to allocate the Call and Reply buffers separately.
TBH, the reliance on using a single buffer for the pair of XDR
buffers is transport implementation-specific.

Instead of passing just the rq_buffer into the buf_free method, pass
the task structure and let buf_free take care of freeing both
XDR buffers at once.

There's a micro-optimization here. In the common case, both
xprt_release and the transport's buf_free method were checking if
rq_buffer was NULL. Now the check is done only once per RPC.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-09-19 13:08:37 -04:00
Trond Myklebust
ad3331acb1 SUNRPC: Fix up socket autodisconnect
Ensure that we don't forget to set up the disconnection timer for the
case when a connect request is fulfilled after the RPC request that
initiated it has timed out or been interrupted.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-08-02 13:47:43 -04:00
Trond Myklebust
f1dc237c60 SUNRPC: Reduce latency when send queue is congested
Use the low latency transport workqueue to process the task that is
next in line on the xprt->sending queue.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-06-13 12:35:51 -04:00
Trond Myklebust
40a5f1b19b SUNRPC: RPC transport queue must be low latency
rpciod can easily get congested due to the long list of queued rpc_tasks.
Having the receive queue wait in turn for those tasks to complete can
therefore be a bottleneck.

Address the problem by separating the workqueues into:
- rpciod: manages rpc_tasks
- xprtiod: manages transport related work.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-06-13 12:35:51 -04:00
Trond Myklebust
fb43d17210 SUNRPC: Use the multipath iterator to assign a transport to each task
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-02-05 18:48:55 -05:00
Trond Myklebust
80b14d5e61 SUNRPC: Add a structure to track multiple transports
In order to support multipathing/trunking we will need the ability to
track multiple transports. This patch sets up a basic structure for
doing so.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-02-05 18:48:54 -05:00
Trond Myklebust
fda1bfef9e SUNRPC: Make freeing of struct xprt rcu-safe
Have it call kfree_rcu() to ensure that we can use it on rcu-protected
lists.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-01-31 21:37:23 -05:00
Trond Myklebust
30c5116b11 SUNRPC: Uninline xprt_get(); It isn't performance critical.
Also allow callers to pass NULL arguments to xprt_get() and xprt_put().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-01-31 21:37:22 -05:00
Chuck Lever
5d252f90a8 svcrdma: Add class for RDMA backwards direction transport
To support the server-side of an NFSv4.1 backchannel on RDMA
connections, add a transport class that enables backward
direction messages on an existing forward channel connection.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-01-19 15:30:48 -05:00
Trond Myklebust
79234c3db6 SUNRPC: Lock the transport layer on shutdown
Avoid all races with the connect/disconnect handlers by taking the
transport lock.

Reported-by:"Suzuki K. Poulose" <suzuki.poulose@arm.com>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-09-19 16:37:43 -04:00
Trond Myklebust
4876cc779f SUNRPC: Ensure we release the TCP socket once it has been closed
This fixes a regression introduced by commit caf4ccd4e8 ("SUNRPC:
Make xs_tcp_close() do a socket shutdown rather than a sock_release").
Prior to that commit, the autoclose feature would ensure that an
idle connection would result in the socket being both disconnected and
released, whereas now only gets disconnected.

While the current behaviour is harmless, it does leave the port bound
until either RPC traffic resumes or the RPC client is shut down.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-06-19 19:20:12 -04:00
Neil Brown
2980731811 SUNRPC: never enqueue a ->rq_cong request on ->sending
If the sending queue has a task without ->rq_cong set at the front,
and then a number of tasks with ->rq_cong set such that they use
the entire congestion window, then the queue deadlocks.  The first
entry cannot be processed until later entries complete.

This scenario has been seen with a client using UDP to access a server,
and the network connection breaking for a period of time - it doesn't
recover.

It never really makes sense for an ->rq_cong request to be on the ->sending
queue, but it can happen when a request is being retried, and finds
the transport if locked (XPRT_LOCKED).  In this case we simple call
__xprt_put_cong() and the deadlock goes away.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-06-16 11:13:21 -04:00
Chuck Lever
4a06825839 SUNRPC: Transport fault injection
It has been exceptionally useful to exercise the logic that handles
local immediate errors and RDMA connection loss.  To enable
developers to test this regularly and repeatably, add logic to
simulate connection loss every so often.

Fault injection is disabled by default. It is enabled with

  $ sudo echo xxx > /sys/kernel/debug/sunrpc/inject_fault/disconnect

where "xxx" is a large positive number of transport method calls
before a disconnect. A value of several thousand is usually a good
number that allows reasonable forward progress while still causing a
lot of connection drops.

These hooks are disabled when SUNRPC_DEBUG is turned off.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-06-10 18:37:26 -04:00
Trond Myklebust
21330b6670 Merge branch 'bugfixes'
* bugfixes:
  NFSv4: Return delegations synchronously in evict_inode
  SUNRPC: Fix a regression when reconnecting
  NFS: remount with security change should return EINVAL
  nfs: do not export discarded symbols
  NFSv4.1: don't export static symbol
2015-04-23 15:16:27 -04:00
Jeff Layton
3f94009816 sunrpc: make debugfs file creation failure non-fatal
v2: gracefully handle the case where some dentry pointers end up NULL
    and be more dilligent about zeroing out dentry pointers

We currently have a problem that SELinux policy is being enforced when
creating debugfs files. If a debugfs file is created as a side effect of
doing some syscall, then that creation can fail if the SELinux policy
for that process prevents it.

This seems wrong. We don't do that for files under /proc, for instance,
so Bruce has proposed a patch to fix that.

While discussing that patch however, Greg K.H. stated:

    "No kernel code should care / fail if a debugfs function fails, so
     please fix up the sunrpc code first."

This patch converts all of the sunrpc debugfs setup code to be void
return functins, and the callers to not look for errors from those
functions.

This should allow rpc_clnt and rpc_xprt creation to work, even if the
kernel fails to create debugfs files for some reason.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-04-23 14:42:27 -04:00
Trond Myklebust
0695314ef0 SUNRPC: Fix a regression when reconnecting
If the task needs to give up the socket lock in order to allow a
reconnect to occur, then it must also clear the 'rq_bytes_sent' field
so that when it retransmits, it knows to start from the beginning.

Fixes: 718ba5b873 ("SUNRPC: Add helpers to prevent socket create from racing")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-27 12:24:36 -04:00
Trond Myklebust
9e2b9f3776 SUNRPC: Remove the redundant XPRT_CONNECTION_CLOSE flag
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-09 11:26:06 -05:00
Trond Myklebust
718ba5b873 SUNRPC: Add helpers to prevent socket create from racing
The socket lock is currently held by the task that is requesting the
connection be established. While that is efficient in the case where
the connection happens quickly, it is racy in the case where it doesn't.
What we really want is for the connect helper to be able to block access
to the socket while it is being set up.

This patch does so by arranging to transfer the socket lock from the
task that is requesting the connect attempt, and then releasing that
lock once everything is done.
This scheme also gives us automatic protection against collisions with
the RPC close code, so we can kill the cancel_delayed_work_sync()
call in xs_close().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-08 21:47:29 -05:00
Jeff Layton
388f0c7767 sunrpc: add a debugfs rpc_xprt directory with an info file in it
Add a new directory heirarchy under the debugfs sunrpc/ directory:

    sunrpc/
        rpc_xprt/
            <xprt id>/

Within that directory, we can put files that give info about the
xprts. We do have the (minor) problem that there is no succinct,
unique identifier for rpc_xprts. So we generate them synthetically
with a static atomic_t counter.

For now, this directory just holds an "info" file, but we may add
other files to it in the future.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-27 13:14:52 -05:00
Jeff Layton
f895b252d4 sunrpc: eliminate RPC_DEBUG
It's always set to whatever CONFIG_SUNRPC_DEBUG is, so just use that.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24 17:31:46 -05:00
Jeff Layton
3705ad64f1 sunrpc: add new tracepoints in xprt handling code
...so we can keep track of when calls are sent and replies received.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24 12:53:35 -05:00
Linus Torvalds
06b8ab5528 NFS client updates for Linux 3.17
Highlights include:
 
 - Stable fix for a bug in nfs3_list_one_acl()
 - Speed up NFS path walks by supporting LOOKUP_RCU
 - More read/write code cleanups
 - pNFS fixes for layout return on close
 - Fixes for the RCU handling in the rpcsec_gss code
 - More NFS/RDMA fixes
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Merge tag 'nfs-for-3.17-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

   - stable fix for a bug in nfs3_list_one_acl()
   - speed up NFS path walks by supporting LOOKUP_RCU
   - more read/write code cleanups
   - pNFS fixes for layout return on close
   - fixes for the RCU handling in the rpcsec_gss code
   - more NFS/RDMA fixes"

* tag 'nfs-for-3.17-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (79 commits)
  nfs: reject changes to resvport and sharecache during remount
  NFS: Avoid infinite loop when RELEASE_LOCKOWNER getting expired error
  SUNRPC: remove all refcounting of groupinfo from rpcauth_lookupcred
  NFS: fix two problems in lookup_revalidate in RCU-walk
  NFS: allow lockless access to access_cache
  NFS: teach nfs_lookup_verify_inode to handle LOOKUP_RCU
  NFS: teach nfs_neg_need_reval to understand LOOKUP_RCU
  NFS: support RCU_WALK in nfs_permission()
  sunrpc/auth: allow lockless (rcu) lookup of credential cache.
  NFS: prepare for RCU-walk support but pushing tests later in code.
  NFS: nfs4_lookup_revalidate: only evaluate parent if it will be used.
  NFS: add checks for returned value of try_module_get()
  nfs: clear_request_commit while holding i_lock
  pnfs: add pnfs_put_lseg_async
  pnfs: find swapped pages on pnfs commit lists too
  nfs: fix comment and add warn_on for PG_INODE_REF
  nfs: check wait_on_bit_lock err in page_group_lock
  sunrpc: remove "ec" argument from encrypt_v2 operation
  sunrpc: clean up sparse endianness warnings in gss_krb5_wrap.c
  sunrpc: clean up sparse endianness warnings in gss_krb5_seal.c
  ...
2014-08-13 18:13:19 -06:00
Chuck Lever
3c45ddf823 svcrdma: Select NFSv4.1 backchannel transport based on forward channel
The current code always selects XPRT_TRANSPORT_BC_TCP for the back
channel, even when the forward channel was not TCP (eg, RDMA). When
a 4.1 mount is attempted with RDMA, the server panics in the TCP BC
code when trying to send CB_NULL.

Instead, construct the transport protocol number from the forward
channel transport or'd with XPRT_TRANSPORT_BC. Transports that do
not support bi-directional RPC will not have registered a "BC"
transport, causing create_backchannel_client() to fail immediately.

Fixes: https://bugzilla.linux-nfs.org/show_bug.cgi?id=265
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-18 11:35:45 -04:00
Trond Myklebust
2fc193cf92 SUNRPC: Handle EPIPE in xprt_connect_status
The callback handler xs_error_report() can end up propagating an EPIPE
error by means of the call to xprt_wake_pending_tasks(). Ensure that
xprt_connect_status() does not automatically convert this into an
EIO error.

Reported-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-07-03 00:11:35 -04:00
Linus Torvalds
d1e1cda862 NFS client updates for Linux 3.16
Highlights include:
 
 - Massive cleanup of the NFS read/write code by Anna and Dros
 - Support multiple NFS read/write requests per page in order to deal with
   non-page aligned pNFS striping. Also cleans up the r/wsize < page size
   code nicely.
 - stable fix for ensuring inode is declared uptodate only after all the
   attributes have been checked.
 - stable fix for a kernel Oops when remounting
 - NFS over RDMA client fixes
 - move the pNFS files layout driver into its own subdirectory
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Merge tag 'nfs-for-3.16-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

   - massive cleanup of the NFS read/write code by Anna and Dros
   - support multiple NFS read/write requests per page in order to deal
     with non-page aligned pNFS striping.  Also cleans up the r/wsize <
     page size code nicely.
   - stable fix for ensuring inode is declared uptodate only after all
     the attributes have been checked.
   - stable fix for a kernel Oops when remounting
   - NFS over RDMA client fixes
   - move the pNFS files layout driver into its own subdirectory"

* tag 'nfs-for-3.16-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (79 commits)
  NFS: populate ->net in mount data when remounting
  pnfs: fix lockup caused by pnfs_generic_pg_test
  NFSv4.1: Fix typo in dprintk
  NFSv4.1: Comment is now wrong and redundant to code
  NFS: Use raw_write_seqcount_begin/end int nfs4_reclaim_open_state
  xprtrdma: Disconnect on registration failure
  xprtrdma: Remove BUG_ON() call sites
  xprtrdma: Avoid deadlock when credit window is reset
  SUNRPC: Move congestion window constants to header file
  xprtrdma: Reset connection timeout after successful reconnect
  xprtrdma: Use macros for reconnection timeout constants
  xprtrdma: Allocate missing pagelist
  xprtrdma: Remove Tavor MTU setting
  xprtrdma: Ensure ia->ri_id->qp is not NULL when reconnecting
  xprtrdma: Reduce the number of hardway buffer allocations
  xprtrdma: Limit work done by completion handler
  xprtrmda: Reduce calls to ib_poll_cq() in completion handlers
  xprtrmda: Reduce lock contention in completion handlers
  xprtrdma: Split the completion queue
  xprtrdma: Make rpcrdma_ep_destroy() return void
  ...
2014-06-10 15:02:42 -07:00
Chuck Lever
4f4cf5ad6f SUNRPC: Move congestion window constants to header file
I would like to use one of the RPC client's congestion algorithm
constants in transport-specific code.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-06-04 08:56:51 -04:00