Commit Graph

149 Commits

Author SHA1 Message Date
Nicholas Mc Guire 55cc1d7806 SUNRPC: fix build-warning due to format missmatch
fix build-warning introduced by commit: f0eede10fd ("SUNRPC: use
jiffies_to_msecs for converting jiffies") which did not fixup
the format properly (my bad).

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-13 09:05:20 -04:00
Nicholas Mc Guire f0eede10fd SUNRPC: use jiffies_to_msecs for converting jiffies
Use jiffies_to_msecs for converting jiffies as it handles all of the corner
cases reliably and also helps readability.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-12 11:53:55 -04:00
Trond Myklebust c4a7ca7749 SUNRPC: Allow waiting on memory allocation
We should be safe now, as long as we don't do GFP_IO or higher allocations

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-24 18:46:50 -05:00
Trond Myklebust 127b21b89f SUNRPC: Adjust rpciod workqueue parameters
Increase the concurrency level for rpciod threads to allow for allocations
etc that happen in the RPCSEC_GSS layer. Also note that the NFSv4 byte range
locks may now need to allocate memory from inside rpciod.

Add the WQ_HIGHPRI flag to improve latency guarantees while we're at it.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-24 18:46:49 -05:00
Jeff Layton 1306729b0d sunrpc: eliminate RPC_TRACEPOINTS
It's always set to the same value as CONFIG_TRACEPOINTS, so we can just
use that instead.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24 17:33:12 -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
NeilBrown 1aff525629 NFS/SUNRPC: Remove other deadlock-avoidance mechanisms in nfs_release_page()
Now that nfs_release_page() doesn't block indefinitely, other deadlock
avoidance mechanisms aren't needed.
 - it doesn't hurt for kswapd to block occasionally.  If it doesn't
   want to block it would clear __GFP_WAIT.  The current_is_kswapd()
   was only added to avoid deadlocks and we have a new approach for
   that.
 - memory allocation in the SUNRPC layer can very rarely try to
   ->releasepage() a page it is trying to handle.  The deadlock
   is removed as nfs_release_page() doesn't block indefinitely.

So we don't need to set PF_FSTRANS for sunrpc network operations any
more.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-09-25 08:25:47 -04:00
NeilBrown c1221321b7 sched: Allow wait_on_bit_action() functions to support a timeout
It is currently not possible for various wait_on_bit functions
to implement a timeout.

While the "action" function that is called to do the waiting
could certainly use schedule_timeout(), there is no way to carry
forward the remaining timeout after a false wake-up.
As false-wakeups a clearly possible at least due to possible
hash collisions in bit_waitqueue(), this is a real problem.

The 'action' function is currently passed a pointer to the word
containing the bit being waited on.  No current action functions
use this pointer.  So changing it to something else will be a
little noisy but will have no immediate effect.

This patch changes the 'action' function to take a pointer to
the "struct wait_bit_key", which contains a pointer to the word
containing the bit so nothing is really lost.

It also adds a 'private' field to "struct wait_bit_key", which
is initialized to zero.

An action function can now implement a timeout with something
like

static int timed_out_waiter(struct wait_bit_key *key)
{
	unsigned long waited;
	if (key->private == 0) {
		key->private = jiffies;
		if (key->private == 0)
			key->private -= 1;
	}
	waited = jiffies - key->private;
	if (waited > 10 * HZ)
		return -EAGAIN;
	schedule_timeout(waited - 10 * HZ);
	return 0;
}

If any other need for context in a waiter were found it would be
easy to use ->private for some other purpose, or even extend
"struct wait_bit_key".

My particular need is to support timeouts in nfs_release_page()
to avoid deadlocks with loopback mounted NFS.

While wait_on_bit_timeout() would be a cleaner interface, it
will not meet my need.  I need the timeout to be sensitive to
the state of the connection with the server, which could change.
 So I need to use an 'action' interface.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051604.28027.41257.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-16 15:10:41 +02:00
David Rientjes c6c8fe79a8 net, sunrpc: suppress allocation warning in rpc_malloc()
rpc_malloc() allocates with GFP_NOWAIT without making any attempt at
reclaim so it easily fails when low on memory.  This ends up spamming the
kernel log:

SLAB: Unable to allocate memory on node 0 (gfp=0x4000)
  cache: kmalloc-8192, object size: 8192, order: 1
  node 0: slabs: 207/207, objs: 207/207, free: 0
rekonq: page allocation failure: order:1, mode:0x204000
CPU: 2 PID: 14321 Comm: rekonq Tainted: G           O  3.15.0-rc3-12.gfc9498b-desktop+ #6
Hardware name: System manufacturer System Product Name/M4A785TD-V EVO, BIOS 2105    07/23/2010
 0000000000000000 ffff880010ff17d0 ffffffff815e693c 0000000000204000
 ffff880010ff1858 ffffffff81137bd2 0000000000000000 0000001000000000
 ffff88011ffebc38 0000000000000001 0000000000204000 ffff88011ffea000
Call Trace:
 [<ffffffff815e693c>] dump_stack+0x4d/0x6f
 [<ffffffff81137bd2>] warn_alloc_failed+0xd2/0x140
 [<ffffffff8113be19>] __alloc_pages_nodemask+0x7e9/0xa30
 [<ffffffff811824a8>] kmem_getpages+0x58/0x140
 [<ffffffff81183de6>] fallback_alloc+0x1d6/0x210
 [<ffffffff81183be3>] ____cache_alloc_node+0x123/0x150
 [<ffffffff81185953>] __kmalloc+0x203/0x490
 [<ffffffffa06b0ee2>] rpc_malloc+0x32/0xa0 [sunrpc]
 [<ffffffffa06a6999>] call_allocate+0xb9/0x170 [sunrpc]
 [<ffffffffa06b19d8>] __rpc_execute+0x88/0x460 [sunrpc]
 [<ffffffffa06b2da9>] rpc_execute+0x59/0xc0 [sunrpc]
 [<ffffffffa06a932b>] rpc_run_task+0x6b/0x90 [sunrpc]
 [<ffffffffa077b5c1>] nfs4_call_sync_sequence+0x51/0x80 [nfsv4]
 [<ffffffffa077d45d>] _nfs4_do_setattr+0x1ed/0x280 [nfsv4]
 [<ffffffffa0782a72>] nfs4_do_setattr+0x72/0x180 [nfsv4]
 [<ffffffffa078334c>] nfs4_proc_setattr+0xbc/0x140 [nfsv4]
 [<ffffffffa074a7e8>] nfs_setattr+0xd8/0x240 [nfs]
 [<ffffffff811baa71>] notify_change+0x231/0x380
 [<ffffffff8119cf5c>] chmod_common+0xfc/0x120
 [<ffffffff8119df80>] SyS_chmod+0x40/0x90
 [<ffffffff815f4cfd>] system_call_fastpath+0x1a/0x1f
...

If the allocation fails, simply return NULL and avoid spamming the kernel
log.

Reported-by: Marc Dietrich <marvin24@gmx.de>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-05-29 11:11:51 -04:00
Trond Myklebust 6bd144160a SUNRPC: Don't let rpc_delay() clobber non-timeout errors
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-03-20 13:38:43 -04:00
Trond Myklebust 8d1018c774 SUNRPC: Ensure rpc_task->tk_pid is available for tracepoints
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-09-04 14:45:13 -04:00
Linus Torvalds be0c5d8c0b NFS client updates for Linux 3.11
Feature highlights include:
 - Add basic client support for NFSv4.2
 - Add basic client support for Labeled NFS (selinux for NFSv4.2)
 - Fix the use of credentials in NFSv4.1 stateful operations, and
   add support for NFSv4.1 state protection.
 
 Bugfix highlights:
 - Fix another NFSv4 open state recovery race
 - Fix an NFSv4.1 back channel session regression
 - Various rpc_pipefs races
 - Fix another issue with NFSv3 auth negotiation
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Merge tag 'nfs-for-3.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Feature highlights include:
   - Add basic client support for NFSv4.2
   - Add basic client support for Labeled NFS (selinux for NFSv4.2)
   - Fix the use of credentials in NFSv4.1 stateful operations, and add
     support for NFSv4.1 state protection.

  Bugfix highlights:
   - Fix another NFSv4 open state recovery race
   - Fix an NFSv4.1 back channel session regression
   - Various rpc_pipefs races
   - Fix another issue with NFSv3 auth negotiation

  Please note that Labeled NFS does require some additional support from
  the security subsystem.  The relevant changesets have all been
  reviewed and acked by James Morris."

* tag 'nfs-for-3.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (54 commits)
  NFS: Set NFS_CS_MIGRATION for NFSv4 mounts
  NFSv4.1 Refactor nfs4_init_session and nfs4_init_channel_attrs
  nfs: have NFSv3 try server-specified auth flavors in turn
  nfs: have nfs_mount fake up a auth_flavs list when the server didn't provide it
  nfs: move server_authlist into nfs_try_mount_request
  nfs: refactor "need_mount" code out of nfs_try_mount
  SUNRPC: PipeFS MOUNT notification optimization for dying clients
  SUNRPC: split client creation routine into setup and registration
  SUNRPC: fix races on PipeFS UMOUNT notifications
  SUNRPC: fix races on PipeFS MOUNT notifications
  NFSv4.1 use pnfs_device maxcount for the objectlayout gdia_maxcount
  NFSv4.1 use pnfs_device maxcount for the blocklayout gdia_maxcount
  NFSv4.1 Fix gdia_maxcount calculation to fit in ca_maxresponsesize
  NFS: Improve legacy idmapping fallback
  NFSv4.1 end back channel session draining
  NFS: Apply v4.1 capabilities to v4.2
  NFSv4.1: Clean up layout segment comparison helper names
  NFSv4.1: layout segment comparison helpers should take 'const' parameters
  NFSv4: Move the DNS resolver into the NFSv4 module
  rpc_pipefs: only set rpc_dentry_ops if d_op isn't already set
  ...
2013-07-09 12:09:43 -07:00
Rafael J. Wysocki 207bc1181b Merge branch 'freezer'
* freezer:
  af_unix: use freezable blocking calls in read
  sigtimedwait: use freezable blocking call
  nanosleep: use freezable blocking call
  futex: use freezable blocking call
  select: use freezable blocking call
  epoll: use freezable blocking call
  binder: use freezable blocking calls
  freezer: add new freezable helpers using freezer_do_not_count()
  freezer: convert freezable helpers to static inline where possible
  freezer: convert freezable helpers to freezer_do_not_count()
  freezer: skip waking up tasks with PF_FREEZER_SKIP set
  freezer: shorten freezer sleep time using exponential backoff
  lockdep: check that no locks held at freeze time
  lockdep: remove task argument from debug_check_no_locks_held
  freezer: add unsafe versions of freezable helpers for CIFS
  freezer: add unsafe versions of freezable helpers for NFS
2013-06-28 13:00:53 +02:00
Trond Myklebust 9ec2ef53b9 SUNRPC: Remove redundant call to rpc_set_running() in __rpc_execute()
The RPC_TASK_RUNNING flag will always have been set in rpc_make_runnable()
once we get past the test for out_of_line_wait_on_bit() returning
ERESTARTSYS.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-06-06 16:24:40 -04:00
Trond Myklebust 0053a8e65c SUNRPC: Remove unused function rpc_queue_empty
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-06-06 16:24:39 -04:00
Trond Myklebust a76580fbf0 SUNRPC: Fix a potential race in rpc_execute
If the rpc_task is asynchronous, it could theoretically finish executing
on the workqueue it was assigned by rpc_make_runnable() before we get
round to testing RPC_IS_ASYNC() in rpc_execute.

In practice, however, all the existing callers hold a reference to the
rpc_task, so this can't happen today...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-06-06 16:24:38 -04:00
Trond Myklebust a3c3cac5d3 SUNRPC: Prevent an rpc_task wakeup race
The lockless RPC_IS_QUEUED() test in __rpc_execute means that we need to
be careful about ordering the calls to rpc_test_and_set_running(task) and
rpc_clear_queued(task). If we get the order wrong, then we may end up
testing the RPC_TASK_RUNNING flag after __rpc_execute() has looped
and changed the state of the rpc_task.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
2013-05-22 14:55:32 -04:00
Colin Cross 416ad3c9c0 freezer: add unsafe versions of freezable helpers for NFS
NFS calls the freezable helpers with locks held, which is unsafe
and will cause lockdep warnings when 6aa9707 "lockdep: check
that no locks held at freeze time" is reapplied (it was reverted
in dbf520a).  NFS shouldn't be doing this, but it has
long-running syscalls that must hold a lock but also shouldn't
block suspend.  Until NFS freeze handling is rewritten to use a
signal to exit out of the critical section, add new *_unsafe
versions of the helpers that will not run the lockdep test when
6aa9707 is reapplied, and call them from NFS.

In practice the likley result of holding the lock while freezing
is that a second task blocked on the lock will never freeze,
aborting suspend, but it is possible to manufacture a case using
the cgroup freezer, the lock, and the suspend freezer to create
a deadlock.  Silencing the lockdep warning here will allow
problems to be found in other drivers that may have a more
serious deadlock risk, and prevent new problems from being added.

Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-12 14:16:21 +02:00
Trond Myklebust 1166fde6a9 SUNRPC: Add barriers to ensure read ordering in rpc_wake_up_task_queue_locked
We need to be careful when testing task->tk_waitqueue in
rpc_wake_up_task_queue_locked, because it can be changed while we
are holding the queue->lock.
By adding appropriate memory barriers, we can ensure that it is safe to
test task->tk_waitqueue for equality if the RPC_TASK_QUEUED bit is set.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
2013-03-25 11:23:40 -04:00
Trond Myklebust edd2e36fe8 SUNRPC: When changing the queue priority, ensure that we change the owner
This fixes a livelock in the xprt->sending queue where we end up never
making progress on lower priority tasks because sleep_on_priority()
keeps adding new tasks with the same owner to the head of the queue,
and priority bumps mean that we keep resetting the queue->owner to
whatever task is at the head of the queue.

Regression introduced by commit c05eecf636
(SUNRPC: Don't allow low priority tasks to pre-empt higher priority ones).

Reported-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-01-30 17:45:14 -05:00
Trond Myklebust 87ed50036b SUNRPC: Ensure we release the socket write lock if the rpc_task exits early
If the rpc_task exits while holding the socket write lock before it has
allocated an rpc slot, then the usual mechanism for releasing the write
lock in xprt_release() is defeated.

The problem occurs if the call to xprt_lock_write() initially fails, so
that the rpc_task is put on the xprt->sending wait queue. If the task
exits after being assigned the lock by __xprt_lock_write_func, but
before it has retried the call to xprt_lock_and_alloc_slot(), then
it calls xprt_release() while holding the write lock, but will
immediately exit due to the test for task->tk_rqstp != NULL.

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.1]
2013-01-08 14:30:43 -05:00
Trond Myklebust c6567ed140 SUNRPC: Ensure that we free the rpc_task after cleanups are done
This patch ensures that we free the rpc_task after the cleanup callbacks
are done in order to avoid a deadlock problem that can be triggered if
the callback needs to wait for another workqueue item to complete.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Weston Andros Adamson <dros@netapp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Bruce Fields <bfields@fieldses.org>
Cc: stable@vger.kernel.org
2013-01-04 12:53:59 -05:00
Trond Myklebust c05eecf636 SUNRPC: Don't allow low priority tasks to pre-empt higher priority ones
Currently, the priority queues attempt to be 'fair' to lower priority
tasks by scheduling them after a certain number of higher priority tasks
have run. The problem is that both the transport send queue and
the NFSv4.1 session slot queue have strong ordering requirements.

This patch therefore removes the fairness code in favour of strong
ordering of task priorities.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-06 00:30:53 +01:00
Trond Myklebust 1e1093c7fd NFSv4.1: Don't mess with task priorities in nfs41_setup_sequence
We want to preserve the rpc_task priority for things like writebacks,
that may have differing levels of urgency.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-06 00:30:51 +01:00
Weston Andros Adamson 0a0c2a57bc SUNRPC: remove BUG_ON in rpc_release_task
Replace BUG_ON() with WARN_ON_ONCE().

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:43 -05:00
Weston Andros Adamson 2bd4eef87b SUNRPC: remove BUG_ONs checking RPC_IS_QUEUED
Replace two BUG_ON() calls with WARN_ON_ONCE() and early returns.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:42 -05:00
Weston Andros Adamson f50ad42837 SUNRPC: remove BUG_ON from __rpc_sleep_on_priority
Replace BUG_ON() with WARN_ON_ONCE().

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:42 -05:00
Weston Andros Adamson e454a7a83d SUNRPC: remove BUG_ON from rpc_sleep_on*
Replace BUG_ON() with WARN_ON_ONCE() and clean up after inactive task.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:40 -05:00
Trond Myklebust 9b96ce7197 SUNRPC: Limit the rpciod workqueue concurrency
We shouldn't need more than 1 worker thread per cpu, since rpciod
is designed to run without sleeping in most cases.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-09-28 20:24:16 -04:00
Linus Torvalds ac694dbdbc Merge branch 'akpm' (Andrew's patch-bomb)
Merge Andrew's second set of patches:
 - MM
 - a few random fixes
 - a couple of RTC leftovers

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (120 commits)
  rtc/rtc-88pm80x: remove unneed devm_kfree
  rtc/rtc-88pm80x: assign ret only when rtc_register_driver fails
  mm: hugetlbfs: close race during teardown of hugetlbfs shared page tables
  tmpfs: distribute interleave better across nodes
  mm: remove redundant initialization
  mm: warn if pg_data_t isn't initialized with zero
  mips: zero out pg_data_t when it's allocated
  memcg: gix memory accounting scalability in shrink_page_list
  mm/sparse: remove index_init_lock
  mm/sparse: more checks on mem_section number
  mm/sparse: optimize sparse_index_alloc
  memcg: add mem_cgroup_from_css() helper
  memcg: further prevent OOM with too many dirty pages
  memcg: prevent OOM with too many dirty pages
  mm: mmu_notifier: fix freed page still mapped in secondary MMU
  mm: memcg: only check anon swapin page charges for swap cache
  mm: memcg: only check swap cache pages for repeated charging
  mm: memcg: split swapin charge function into private and public part
  mm: memcg: remove needless !mm fixup to init_mm when charging
  mm: memcg: remove unneeded shmem charge type
  ...
2012-07-31 19:25:39 -07:00
Mel Gorman a564b8f039 nfs: enable swap on NFS
Implement the new swapfile a_ops for NFS and hook up ->direct_IO.  This
will set the NFS socket to SOCK_MEMALLOC and run socket reconnect under
PF_MEMALLOC as well as reset SOCK_MEMALLOC before engaging the protocol
->connect() method.

PF_MEMALLOC should allow the allocation of struct socket and related
objects and the early (re)setting of SOCK_MEMALLOC should allow us to
receive the packets required for the TCP connection buildup.

[jlayton@redhat.com: Restore PF_MEMALLOC task flags in all cases]
[dfeng@redhat.com: Fix handling of multiple swap files]
[a.p.zijlstra@chello.nl: Original patch]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-31 18:42:48 -07:00
Jeff Layton 5cf02d09b5 nfs: skip commit in releasepage if we're freeing memory for fs-related reasons
We've had some reports of a deadlock where rpciod ends up with a stack
trace like this:

    PID: 2507   TASK: ffff88103691ab40  CPU: 14  COMMAND: "rpciod/14"
     #0 [ffff8810343bf2f0] schedule at ffffffff814dabd9
     #1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs]
     #2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f
     #3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8
     #4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs]
     #5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs]
     #6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670
     #7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271
     #8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638
     #9 [ffff8810343bf818] shrink_zone at ffffffff8112788f
    #10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e
    #11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f
    #12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad
    #13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942
    #14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a
    #15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9
    #16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b
    #17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808
    #18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c
    #19 [ffff8810343bfce8] inet_create at ffffffff81483ba6
    #20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7
    #21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc]
    #22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc]
    #23 [ffff8810343bfe38] worker_thread at ffffffff810887d0
    #24 [ffff8810343bfee8] kthread at ffffffff8108dd96
    #25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca

rpciod is trying to allocate memory for a new socket to talk to the
server. The VM ends up calling ->releasepage to get more memory, and it
tries to do a blocking commit. That commit can't succeed however without
a connected socket, so we deadlock.

Fix this by setting PF_FSTRANS on the workqueue task prior to doing the
socket allocation, and having nfs_release_page check for that flag when
deciding whether to do a commit call. Also, set PF_FSTRANS
unconditionally in rpc_async_schedule since that function can also do
allocations sometimes.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
2012-07-30 18:55:59 -04:00
Jeff Layton 506026c3ec sunrpc: clarify comments on rpc_make_runnable
rpc_make_runnable is not generally called with the queue lock held, unless
it's waking up a task that has been sitting on a waitqueue. This is safe
when the task has not entered the FSM yet, but the comments don't really
spell this out.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-07-30 18:55:08 -04:00
Trond Myklebust 540a0f7584 SUNRPC: We must not use list_for_each_entry_safe() in rpc_wake_up()
The problem is that for the case of priority queues, we
have to assume that __rpc_remove_wait_queue_priority will move new
elements from the tk_wait.links lists into the queue->tasks[] list.
We therefore cannot use list_for_each_entry_safe() on queue->tasks[],
since that will skip these new tasks that __rpc_remove_wait_queue_priority
is adding.

Without this fix, rpc_wake_up and rpc_wake_up_status will both fail
to wake up all functions on priority wait queues, which can result
in some nasty hangs.

Reported-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
2012-03-19 14:15:02 -04:00
Trond Myklebust 2f09c24216 SUNRPC: Ensure that we can trace waitqueues when !defined(CONFIG_SYSCTL)
The tracepoint code relies on the queue->name being defined in order to
be able to display the name of the waitqueue on which an RPC task is
sleeping.

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
2012-02-15 00:19:51 -05:00
Trond Myklebust 82b0a4c3c1 SUNRPC: Add trace events to the sunrpc subsystem
Add declarations to allow tracing of RPC call creation, running, sleeping,
and destruction.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-31 19:28:21 -05:00
Trond Myklebust 961a828df6 SUNRPC: Fix potential races in xprt_lock_write_next()
We have to ensure that the wake up from the waitqueue and the assignment
of xprt->snd_task are atomic. We can do this by assigning the snd_task
while under the waitqueue spinlock.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-31 19:28:08 -05:00
Rafael J. Wysocki b00f4dc5ff Merge branch 'master' into pm-sleep
* master: (848 commits)
  SELinux: Fix RCU deref check warning in sel_netport_insert()
  binary_sysctl(): fix memory leak
  mm/vmalloc.c: remove static declaration of va from __get_vm_area_node
  ipmi_watchdog: restore settings when BMC reset
  oom: fix integer overflow of points in oom_badness
  memcg: keep root group unchanged if creation fails
  nilfs2: potential integer overflow in nilfs_ioctl_clean_segments()
  nilfs2: unbreak compat ioctl
  cpusets: stall when updating mems_allowed for mempolicy or disjoint nodemask
  evm: prevent racing during tfm allocation
  evm: key must be set once during initialization
  mmc: vub300: fix type of firmware_rom_wait_states module parameter
  Revert "mmc: enable runtime PM by default"
  mmc: sdhci: remove "state" argument from sdhci_suspend_host
  x86, dumpstack: Fix code bytes breakage due to missing KERN_CONT
  IB/qib: Correct sense on freectxts increment and decrement
  RDMA/cma: Verify private data length
  cgroups: fix a css_set not found bug in cgroup_attach_proc
  oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
  Revert "xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from old kernel"
  ...

Conflicts:
	kernel/cgroup_freezer.c
2011-12-21 21:59:45 +01:00
Jeff Layton d310310cbf Freezer / sunrpc / NFS: don't allow TASK_KILLABLE sleeps to block the freezer
Allow the freezer to skip wait_on_bit_killable sleeps in the sunrpc
layer. This should allow suspend and hibernate events to proceed, even
when there are RPC's pending on the wire.

Also, wrap the TASK_KILLABLE sleeps in NFS layer in freezer_do_not_count
and freezer_count calls. This allows the freezer to skip tasks that are
sleeping while looping on EJUKEBOX or NFS4ERR_DELAY sorts of errors.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-12-06 22:12:27 +01:00
Trond Myklebust 7fdcf13b29 SUNRPC: Fix the execution time statistics in the face of RPC restarts
If the rpc_task gets restarted, then we want to ensure that we don't
double-count the execution time statistics, timeout data, etc.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-12-01 14:00:15 -05:00
Trond Myklebust 3b27bad7f7 SUNRPC: Allow caller of rpc_sleep_on() to select priority levels
Currently, the caller has to change the value of task->tk_priority if
it wants to select on which priority level the task will sleep.

This patch allows the caller to select a priority level at sleep time
rather than always using task->tk_priority.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-07-17 18:11:34 -04:00
Trond Myklebust b55c59892e SUNRPC: Fix a race between work-queue and rpc_killall_tasks
Since rpc_killall_tasks may modify the rpc_task's tk_action field
without any locking, we need to be careful when dereferencing it.

Reported-by: Ben Greear <greearb@candelatech.com>
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
2011-07-07 20:45:37 -04:00
Trond Myklebust 0b760113a3 NLM: Don't hang forever on NLM unlock requests
If the NLM daemon is killed on the NFS server, we can currently end up
hanging forever on an 'unlock' request, instead of aborting. Basically,
if the rpcbind request fails, or the server keeps returning garbage, we
really want to quit instead of retrying.

Tested-by: Vasily Averin <vvs@sw.ru>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
2011-06-15 11:24:27 -04:00
OGAWA Hirofumi a271c5a0de NFS: Ensure that rpc_release_resources_task() can be called twice.
BUG: atomic_dec_and_test(): -1: atomic counter underflow at:
Pid: 2827, comm: mount.nfs Not tainted 2.6.38 #1
Call Trace:
 [<ffffffffa02223a0>] ? put_rpccred+0x44/0x14e [sunrpc]
 [<ffffffffa021bbe9>] ? rpc_ping+0x4e/0x58 [sunrpc]
 [<ffffffffa021c4a5>] ? rpc_create+0x481/0x4fc [sunrpc]
 [<ffffffffa022298a>] ? rpcauth_lookup_credcache+0xab/0x22d [sunrpc]
 [<ffffffffa028be8c>] ? nfs_create_rpc_client+0xa6/0xeb [nfs]
 [<ffffffffa028c660>] ? nfs4_set_client+0xc2/0x1f9 [nfs]
 [<ffffffffa028cd3c>] ? nfs4_create_server+0xf2/0x2a6 [nfs]
 [<ffffffffa0295d07>] ? nfs4_remote_mount+0x4e/0x14a [nfs]
 [<ffffffff810dd570>] ? vfs_kern_mount+0x6e/0x133
 [<ffffffffa029605a>] ? nfs_do_root_mount+0x76/0x95 [nfs]
 [<ffffffffa029643d>] ? nfs4_try_mount+0x56/0xaf [nfs]
 [<ffffffffa0297434>] ? nfs_get_sb+0x435/0x73c [nfs]
 [<ffffffff810dd59b>] ? vfs_kern_mount+0x99/0x133
 [<ffffffff810dd693>] ? do_kern_mount+0x48/0xd8
 [<ffffffff810f5b75>] ? do_mount+0x6da/0x741
 [<ffffffff810f5c5f>] ? sys_mount+0x83/0xc0
 [<ffffffff8100293b>] ? system_call_fastpath+0x16/0x1b

Well, so, I think this is real bug of nfs codes somewhere. With some
review, the code

rpc_call_sync()
    rpc_run_task
        rpc_execute()
            __rpc_execute()
                rpc_release_task()
                    rpc_release_resources_task()
                        put_rpccred()                <= release cred
    rpc_put_task
        rpc_do_put_task()
            rpc_release_resources_task()
                put_rpccred()                        <= release cred again

seems to be release cred unintendedly.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-27 17:55:36 +02:00
Linus Torvalds 179198373c Merge branch 'nfs-for-2.6.39' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'nfs-for-2.6.39' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (54 commits)
  RPC: killing RPC tasks races fixed
  xprt: remove redundant check
  SUNRPC: Convert struct rpc_xprt to use atomic_t counters
  SUNRPC: Ensure we always run the tk_callback before tk_action
  sunrpc: fix printk format warning
  xprt: remove redundant null check
  nfs: BKL is no longer needed, so remove the include
  NFS: Fix a warning in fs/nfs/idmap.c
  Cleanup: Factor out some cut-and-paste code.
  cleanup: save 60 lines/100 bytes by combining two mostly duplicate functions.
  NFS: account direct-io into task io accounting
  gss:krb5 only include enctype numbers in gm_upcall_enctypes
  RPCRDMA: Fix FRMR registration/invalidate handling.
  RPCRDMA: Fix to XDR page base interpretation in marshalling logic.
  NFSv4: Send unmapped uid/gids to the server when using auth_sys
  NFSv4: Propagate the error NFS4ERR_BADOWNER to nfs4_do_setattr
  NFSv4: cleanup idmapper functions to take an nfs_server argument
  NFSv4: Send unmapped uid/gids to the server if the idmapper fails
  NFSv4: If the server sends us a numeric uid/gid then accept it
  NFSv4.1: reject zero layout with zeroed stripe unit
  ...
2011-03-17 17:40:00 -07:00
Trond Myklebust e020c6800c SUNRPC: Ensure we always run the tk_callback before tk_action
This fixes a race in which the task->tk_callback() puts the rpc_task
to sleep, setting a new callback. Under certain circumstances, the current
code may end up executing the task->tk_action before it gets round to the
callback.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
2011-03-17 12:38:41 -04:00
Linus Torvalds bd2895eead Merge branch 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
* 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix build failure introduced by s/freezeable/freezable/
  workqueue: add system_freezeable_wq
  rds/ib: use system_wq instead of rds_ib_fmr_wq
  net/9p: replace p9_poll_task with a work
  net/9p: use system_wq instead of p9_mux_wq
  xfs: convert to alloc_workqueue()
  reiserfs: make commit_wq use the default concurrency level
  ocfs2: use system_wq instead of ocfs2_quota_wq
  ext4: convert to alloc_workqueue()
  scsi/scsi_tgt_lib: scsi_tgtd isn't used in memory reclaim path
  scsi/be2iscsi,qla2xxx: convert to alloc_workqueue()
  misc/iwmc3200top: use system_wq instead of dedicated workqueues
  i2o: use alloc_workqueue() instead of create_workqueue()
  acpi: kacpi*_wq don't need WQ_MEM_RECLAIM
  fs/aio: aio_wq isn't used in memory reclaim path
  input/tps6507x-ts: use system_wq instead of dedicated workqueue
  cpufreq: use system_wq instead of dedicated workqueues
  wireless/ipw2x00: use system_wq instead of dedicated workqueues
  arm/omap: use system_wq in mailbox
  workqueue: use WQ_MEM_RECLAIM instead of WQ_RESCUER
2011-03-16 08:20:19 -07:00
Fred Isaman eabf5baaaa RPC: clarify rpc_run_task error handling
rpc_run_task can only fail if it is not passed in a preallocated task.
However, that is not at all clear with the current code.  So
remove several impossible to occur failure checks.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-11 15:38:40 -05:00
Fred Isaman cee6a5372f RPC: remove check for impossible condition in rpc_make_runnable
queue_work() only returns 0 or 1, never a negative value.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-11 15:38:40 -05:00
Trond Myklebust bf294b41ce SUNRPC: Close a race in __rpc_wait_for_completion_task()
Although they run as rpciod background tasks, under normal operation
(i.e. no SIGKILL), functions like nfs_sillyrename(), nfs4_proc_unlck()
and nfs4_do_close() want to be fully synchronous. This means that when we
exit, we want all references to the rpc_task to be gone, and we want
any dentry references etc. held by that task to be released.

For this reason these functions call __rpc_wait_for_completion_task(),
followed by rpc_put_task() in the expectation that the latter will be
releasing the last reference to the rpc_task, and thus ensuring that the
callback_ops->rpc_release() has been called synchronously.

This patch fixes a race which exists due to the fact that
rpciod calls rpc_complete_task() (in order to wake up the callers of
__rpc_wait_for_completion_task()) and then subsequently calls
rpc_put_task() without ensuring that these two steps are done atomically.

In order to avoid adding new spin locks, the patch uses the existing
waitqueue spin lock to order the rpc_task reference count releases between
the waiting process and rpciod.
The common case where nobody is waiting for completion is optimised for by
checking if the RPC_TASK_ASYNC flag is cleared and/or if the rpc_task
reference count is 1: in those cases we drop trying to grab the spin lock,
and immediately free up the rpc_task.

Those few processes that need to put the rpc_task from inside an
asynchronous context and that do not care about ordering are given a new
helper: rpc_put_task_async().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-03-10 15:04:52 -05:00