linux-stable.git/fs/lockd, branch v4.4.263

lockd: don't use interval-based rebinding over TCP

2020-12-29T12:42:37+00:00

[ Upstream commit 9b82d88d5976e5f2b8015d58913654856576ace5 ]

NLM uses an interval-based rebinding, i.e. it clears the transport's
binding under certain conditions if more than 60 seconds have elapsed
since the connection was last bound.

This rebinding is not necessary for an autobind RPC client over a
connection-oriented protocol like TCP.

It can also cause problems: it is possible for nlm_bind_host() to clear
XPRT_BOUND whilst a connection worker is in the middle of trying to
reconnect, after it had already been checked in xprt_connect().

When the connection worker notices that XPRT_BOUND has been cleared
under it, in xs_tcp_finish_connecting(), that results in:

	xs_tcp_setup_socket: connect returned unhandled error -107

Worse, it's possible that the two can get into lockstep, resulting in
the same behaviour repeated indefinitely, with the above error every
300 seconds, without ever recovering, and the connection never being
established. This has been seen in practice, with a large number of NLM
client tasks, following a server restart.

The existing callers of nlm_bind_host & nlm_rebind_host should not need
to force the rebind, for TCP, so restrict the interval-based rebinding
to UDP only.

For TCP, we will still rebind when needed, e.g. on timeout, and connection
error (including closure), since connection-related errors on an existing
connection, ECONNREFUSED when trying to connect, and rpc_check_timeout(),
already unconditionally clear XPRT_BOUND.

To avoid having to add the fix, and explanation, to both nlm_bind_host()
and nlm_rebind_host(), remove the duplicate code from the former, and
have it call the latter.

Drop the dprintk, which adds no value over a trace.

Signed-off-by: Calum Mackay 
Fixes: 35f5a422ce1a ("SUNRPC: new interface to force an RPC rebind")
Signed-off-by: Trond Myklebust 
Signed-off-by: Sasha Levin

lockd: fix access beyond unterminated strings in prints

2018-11-21T08:27:36+00:00

commit 93f38b6fae0ea8987e22d9e6c38f8dfdccd867ee upstream.

printk format used %*s instead of %.*s, so hostname_len does not limit
the number of bytes accessed from hostname.

Signed-off-by: Amir Goldstein 
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

lockd: lost rollback of set_grace_period() in lockd_down_net()

2018-05-26T06:48:50+00:00

commit 3a2b19d1ee5633f76ae8a88da7bc039a5d1732aa upstream.

Commit efda760fe95ea ("lockd: fix lockd shutdown race") is incorrect,
it removes lockd_manager and disarm grace_period_end for init_net only.

If nfsd was started from another net namespace lockd_up_net() calls
set_grace_period() that adds lockd_manager into per-netns list
and queues grace_period_end delayed work.

These action should be reverted in lockd_down_net().
Otherwise it can lead to double list_add on after restart nfsd in netns,
and to use-after-free if non-disarmed delayed work will be executed after netns destroy.

Fixes: efda760fe95e ("lockd: fix lockd shutdown race")
Cc: stable@vger.kernel.org
Signed-off-by: Vasily Averin 
Signed-off-by: J. Bruce Fields 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

lockd: fix lockd shutdown race

2018-04-13T17:50:02+00:00

[ Upstream commit efda760fe95ea15291853c8fa9235c32d319cd98 ]

As reported by David Jeffery: "a signal was sent to lockd while lockd
was shutting down from a request to stop nfs.  The signal causes lockd
to call restart_grace() which puts the lockd_net structure on the grace
list.  If this signal is received at the wrong time, it will occur after
lockd_down_net() has called locks_end_grace() but before
lockd_down_net() stops the lockd thread.  This leads to lockd putting
the lockd_net structure back on the grace list, then exiting without
anything removing it from the list."

So, perform the final locks_end_grace() from the the lockd thread; this
ensures it's serialized with respect to restart_grace().

Reported-by: David Jeffery 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'nfsd-4.4' of git://linux-nfs.org/~bfields/linux

2015-11-12T04:11:28+00:00

Pull nfsd updates from Bruce Fields:
 "Apologies for coming a little late in the merge window.  Fortunately
  this is another fairly quiet one:

  Mainly smaller bugfixes and cleanup.  We're still finding some bugs
  from the breakup of the big NFSv4 state lock in 3.17 -- thanks
  especially to Andrew Elble and Jeff Layton for tracking down some of
  the remaining races"

* tag 'nfsd-4.4' of git://linux-nfs.org/~bfields/linux:
  svcrpc: document lack of some memory barriers
  nfsd: fix race with open / open upgrade stateids
  nfsd: eliminate sending duplicate and repeated delegations
  nfsd: remove recurring workqueue job to clean DRC
  SUNRPC: drop stale comment in svc_setup_socket()
  nfsd: ensure that seqid morphing operations are atomic wrt to copies
  nfsd: serialize layout stateid morphing operations
  nfsd: improve client_has_state to check for unused openowners
  nfsd: fix clid_inuse on mount with security change
  sunrpc/cache: make cache flushing more reliable.
  nfsd: move include of state.h from trace.c to trace.h
  sunrpc: avoid warning in gss_key_timeout
  lockd: get rid of reference-counted NSM RPC clients
  SUNRPC: Use MSG_SENDPAGE_NOTLAST when calling sendpage()
  lockd: create NSM handles per net namespace
  nfsd: switch unsigned char flags in svc_fh to bools
  nfsd: move svc_fh->fh_maxsize to just after fh_handle
  nfsd: drop null test before destroy functions
  nfsd: serialize state seqid morphing operations

lockd: get rid of reference-counted NSM RPC clients

2015-10-23T19:57:27+00:00

Currently we have reference-counted per-net NSM RPC client
which created on the first monitor request and destroyed
after the last unmonitor request. It's needed because
RPC client need to know 'utsname()->nodename', but utsname()
might be NULL when nsm_unmonitor() called.

So instead of holding the rpc client we could just save nodename
in struct nlm_host and pass it to the rpc_create().
Thus ther is no need in keeping rpc client until last
unmonitor request. We could create separate RPC clients
for each monitor/unmonitor requests.

Signed-off-by: Andrey Ryabinin 
Signed-off-by: J. Bruce Fields

Move locks API users to locks_lock_inode_wait()

2015-10-22T18:57:36+00:00

Instead of having users check for FL_POSIX or FL_FLOCK to call the correct
locks API function, use the check within locks_lock_inode_wait().  This
allows for some later cleanup.

Signed-off-by: Benjamin Coddington 
Signed-off-by: Jeff Layton

lockd: create NSM handles per net namespace

2015-10-12T21:31:05+00:00

Commit cb7323fffa85 ("lockd: create and use per-net NSM
 RPC clients on MON/UNMON requests") introduced per-net
NSM RPC clients. Unfortunately this doesn't make any sense
without per-net nsm_handle.

E.g. the following scenario could happen
Two hosts (X and Y) in different namespaces (A and B) share
the same nsm struct.

1. nsm_monitor(host_X) called => NSM rpc client created,
	nsm->sm_monitored bit set.
2. nsm_mointor(host-Y) called => nsm->sm_monitored already set,
	we just exit. Thus in namespace B ln->nsm_clnt == NULL.
3. host X destroyed => nsm->sm_count decremented to 1
4. host Y destroyed => nsm_unmonitor() => nsm_mon_unmon() => NULL-ptr
	dereference of *ln->nsm_clnt

So this could be fixed by making per-net nsm_handles list,
instead of global. Thus different net namespaces will not be able
share the same nsm_handle.

Signed-off-by: Andrey Ryabinin 
Cc: 
Signed-off-by: J. Bruce Fields

lockd: NLM grace period shouldn't block NFSv4 opens

2015-08-13T14:22:06+00:00

NLM locks don't conflict with NFSv4 share reservations, so we're not
going to learn anything new by watiting for them.

They do conflict with NFSv4 locks and with delegations.

Signed-off-by: J. Bruce Fields

nfsd/sunrpc: turn enqueueing a svc_xprt into a svc_serv operation

2015-08-10T20:05:42+00:00

For now, all services use svc_xprt_do_enqueue, but once we add
workqueue-based service support, we'll need to do something different.

Signed-off-by: Shirley Ma 
Acked-by: Jeff Layton 
Tested-by: Shirley Ma 
Signed-off-by: J. Bruce Fields