RPC task RPC_TASK_QUEUED bit is set must be checked before trying to wake up
task rpc_killall_tasks() because task->tk_waitqueue can not be set (equal to
NULL).
Also, as Trond Myklebust mentioned, such approach (instead of checking
tk_waitqueue to NULL) allows us to "optimise away the call to
rpc_wake_up_queued_task() altogether for those
tasks that aren't queued".
Here is an example of dereferencing of tk_waitqueue equal to NULL:
CPU 0 CPU 1 CPU 2
-------------------- --------------------- --------------------------
nfs4_run_open_task
rpc_run_task
rpc_execute
rpc_set_active
rpc_make_runnable
(waiting)
rpc_async_schedule
nfs4_open_prepare
nfs_wait_on_sequence
nfs_umount_begin
rpc_killall_tasks
rpc_wake_up_task
rpc_wake_up_queued_task
spin_lock(tk_waitqueue == NULL)
BUG()
rpc_sleep_on
spin_lock(&q->lock)
__rpc_sleep_on
task->tk_waitqueue = q
Signed-off-by: Stanislav Kinsbursky <skinsbursky@openvz.org>
Cc: stable@kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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
Fix printk format build warning:
net/sunrpc/xprtrdma/verbs.c:1463: warning: format '%llx' expects type 'long long unsigned int', but argument 3 has type 'dma_addr_t'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
'req' is dereferenced before checked for NULL.
The patch simply removes the check.
Signed-off-by: Jinqiu Yang<crindy646@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Make the value in gm_upcall_enctypes just the enctype values.
This allows the values to be used more easily elsewhere.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
When the rpc_memreg_strategy is 5, FRMR are used to map RPC data.
This mode uses an FRMR to map the RPC data, then invalidates
(i.e. unregisers) the data in xprt_rdma_free. These FRMR are used
across connections on the same mount, i.e. if the connection goes
away on an idle timeout and reconnects later, the FRMR are not
destroyed and recreated.
This creates a problem for transport errors because the WR that
invalidate an FRMR may be flushed (i.e. fail) leaving the
FRMR valid. When the FRMR is later used to map an RPC it will fail,
tearing down the transport and starting over. Over time, more and
more of the FRMR pool end up in the wrong state resulting in
seemingly random disconnects.
This fix keeps track of the FRMR state explicitly by setting it's
state based on the successful completion of a reg/inv WR. If the FRMR
is ever used and found to be in the wrong state, an invalidate WR
is prepended, re-syncing the FRMR state and avoiding the connection loss.
Signed-off-by: Tom Tucker <tom@ogc.us>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The RPCRDMA marshalling logic assumed that xdr->page_base was an
offset into the first page of xdr->page_list. It is in fact an
offset into the xdr->page_list itself, that is, it selects the
first page in the page_list and the offset into that page.
The symptom depended in part on the rpc_memreg_strategy, if it was
FRMR, or some other one-shot mapping mode, the connection would get
torn down on a base and bounds error. When the badly marshalled RPC
was retransmitted it would reconnect, get the error, and tear down the
connection again in a loop forever. This resulted in a hung-mount. For
the other modes, it would result in silent data corruption. This bug is
most easily reproduced by writing more data than the filesystem
has space for.
This fix corrects the page_base assumption and otherwise simplifies
the iov mapping logic.
Signed-off-by: Tom Tucker <tom@ogc.us>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Use our own async error handler.
Mark the layout as failed and retry i/o through the MDS on specified errors.
Update the mds_offset in nfs_readpage_retry so that a failed short-read retry
to a DS gets correctly resent through the MDS.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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>
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>
xs_create_sock() is supposed to return a pointer or an ERR_PTR-encoded
error, but it currently returns 0 if xs_bind() fails.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Cc: stable@kernel.org [v2.6.37]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We leak the memory allocated to 'ctxt' when we return after
'ib_dma_mapping_error()' returns !=0.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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>
Add proper RCU annotations/verbs to sk_wq and wq members
Fix __sctp_write_space() sk_sleep() abuse (and sock->wq access)
Fix sunrpc sk_sleep() abuse too
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The information required to find the nfs_client cooresponding to the incoming
back channel request is contained in the NFS layer. Perform minimal checking
in the RPC layer pg_authenticate method, and push more detailed checking into
the NFS layer where the nfs_client can be found.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
WQ_RESCUER is now an internal flag and should only be used in the
workqueue implementation proper. Use WQ_MEM_RECLAIM instead.
This doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
This allows us to reuse the xprt associated with a server connection if
one has already been set up.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Multiple backchannels can share the same tcp connection; from rfc 5661 section
2.10.3.1:
A connection's association with a session is not exclusive. A
connection associated with the channel(s) of one session may be
simultaneously associated with the channel(s) of other sessions
including sessions associated with other client IDs.
However, multiple backchannels share a connection, they must all share
the same xid stream (hence the same rpc_xprt); the only way we have to
match replies with calls at the rpc layer is using the xid.
So, keep the rpc_xprt around as long as the connection lasts, in case
we're asked to use the connection as a backchannel again.
Requests to create new backchannel clients over a given server
connection should results in creating new clients that reuse the
existing rpc_xprt.
But to start, just reject attempts to associate multiple rpc_xprt's with
the same underlying bc_xprt.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This seems obviously transport-level information even if it's currently
used only by the server socket code.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
vm_map_ram() is not available on NOMMU platforms, and causes trouble
on incoherrent architectures such as ARM when we access the page data
through both the direct and the virtual mapping.
The alternative is to use the direct mapping to access page data
for the case when we are not crossing a page boundary, but to copy
the data into a linear scratch buffer when we are accessing data
that spans page boundaries.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: stable@kernel.org [2.6.37]
Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.
Patched with:
git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
RCU free the struct inode. This will allow:
- Subsequent store-free path walking patch. The inode must be consulted for
permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
to take i_lock no longer need to take sb_inode_list_lock to walk the list in
the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
page lock to follow page->mapping.
The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.
In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.
The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Change d_delete from a dentry deletion notification to a dentry caching
advise, more like ->drop_inode. Require it to be constant and idempotent,
and not take d_lock. This is how all existing filesystems use the callback
anyway.
This makes fine grained dentry locking of dput and dentry lru scanning
much simpler.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Differentiate from server backchannel
Signed-off-by: Andy Adamson <andros@netapp.com>
Acked-by: Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The sessions based callback service is started prior to the CREATE_SESSION call
so that it can handle CB_NULL requests which can be sent before the
CREATE_SESSION call returns and the session ID is known.
Set the callback sessionid after a sucessful CREATE_SESSION.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Move the current sock create and destroy routines into the new transport ops.
Back channel socket will be destroyed by the svc_closs_all call in svc_destroy.
Added check: only TCP supported on shared back channel.
Signed-off-by: Andy Adamson <andros@netapp.com>
Acked-by: Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The NFSv4.1 shared back channel does not need to call svc_drop because the
callback service never outlives the single connection it services, and it
reuses it's buffers and keeps the trasport.
Signed-off-by: Andy Adamson <andros@netapp.com>
Acked-by: Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Supposes cache_check runs simultaneously with an update on a different
CPU:
cache_check task doing update
^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^
1. test for CACHE_VALID 1'. set entry->data
& !CACHE_NEGATIVE
2. use entry->data 2'. set CACHE_VALID
If the two memory writes performed in step 1' and 2' appear misordered
with respect to the reads in step 1 and 2, then the caller could get
stale data at step 2 even though it saw CACHE_VALID set on the cache
entry.
Add memory barriers to prevent this.
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We attempt to turn a cache entry negative in place. But that entry may
already have been filled in by some other task since we last checked
whether it was valid, so we could be modifying an already-valid entry.
If nothing else there's a likely leak in such a case when the entry is
eventually put() and contents are not freed because it has
CACHE_NEGATIVE set.
So, take the cache_lock just as sunrpc_cache_update() does.
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently we use -EAGAIN returns to determine when to drop a deferred
request. On its own, that is error-prone, as it makes us treat -EAGAIN
returns from other functions specially to prevent inadvertent dropping.
So, use a flag on the request instead.
Returning an error on request deferral is still required, to prevent
further processing, but we no longer need worry that an error return on
its own could result in a drop.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Commit d29068c431 "sunrpc: Simplify cache_defer_req and related
functions." asserted that cache_check() could determine success or
failure of cache_defer_req() by checking the CACHE_PENDING bit.
This isn't quite right.
We need to know whether cache_defer_req() created a deferred request,
in which case sending an rpc reply has become the responsibility of the
deferred request, and it is important that we not send our own reply,
resulting in two different replies to the same request.
And the CACHE_PENDING bit doesn't tell us that; we could have
succesfully created a deferred request at the same time as another
thread cleared the CACHE_PENDING bit.
So, partially revert that commit, to ensure that cache_check() returns
-EAGAIN if and only if a deferred request has been created.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: NeilBrown <neilb@suse.de>
[bfields@redhat.com: moved svcauth_unix_purge outside ifdef's.]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Once a sunrpc cache entry is VALID, we should be replacing it (and
allowing any concurrent users to destroy it on last put) instead of
trying to update it in place.
Otherwise someone referencing the ip_map we're modifying here could try
to use the m_client just as we're putting the last reference.
The bug should only be seen by users of the legacy nfsd interfaces.
(Thanks to Neil for suggestion to use sunrpc_invalidate.)
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
And remove unnecessary double semicolon too.
No effect to code, as test is != 0.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently svc_sock_names calls svc_close_xprt on a svc_sock to
which it does not own a reference.
As soon as svc_close_xprt sets XPT_CLOSE, the socket could be
freed by a separate thread (though this is a very unlikely race).
It is safer to hold a reference while calling svc_close_xprt.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The xpt_pool field is only used for reporting BUGs.
And it isn't used correctly.
In particular, when it is cleared in svc_xprt_received before
XPT_BUSY is cleared, there is no guarantee that either the
compiler or the CPU might not re-order to two assignments, just
setting xpt_pool to NULL after XPT_BUSY is cleared.
If a different cpu were running svc_xprt_enqueue at this moment,
it might see XPT_BUSY clear and then xpt_pool non-NULL, and
so BUG.
This could be fixed by calling
smp_mb__before_clear_bit()
before the clear_bit. However as xpt_pool isn't really used,
it seems safest to simply remove xpt_pool.
Another alternate would be to change the clear_bit to
clear_bit_unlock, and the test_and_set_bit to test_and_set_bit_lock.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Now that all client-side XDR decoder routines use xdr_streams, there
should be no need to support the legacy calling sequence [rpc_rqst *,
__be32 *, RPC res *] anywhere. We can construct an xdr_stream in the
generic RPC code, instead of in each decoder function.
This is a refactoring change. It should not cause different behavior.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Now that all client-side XDR encoder routines use xdr_streams, there
should be no need to support the legacy calling sequence [rpc_rqst *,
__be32 *, RPC arg *] anywhere. We can construct an xdr_stream in the
generic RPC code, instead of in each encoder function.
Also, all the client-side encoder functions return 0 now, making a
return value superfluous. Take this opportunity to convert them to
return void instead.
This is a refactoring change. It should not cause different behavior.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up.
Just fixed a panic where the nrprocs field in a different upper layer
client was set by hand incorrectly. Use the compiler-generated method
used by the other upper layer protocols.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up.
The trend in the other XDR encoder functions is to BUG() when encoding
problems occur, since a problem here is always due to a local coding
error. Then, instead of a status, zero is unconditionally returned.
Update the rpcbind XDR encoders to behave this way.
To finish the update, use the new-style be32_to_cpup() and
cpu_to_be32() macros, and compute the buffer sizes using raw integers
instead of sizeof(). This matches the conventions used in other XDR
functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
cancel_rearming_delayed_work[queue]() has been superceded by
cancel_delayed_work_sync() quite some time ago. Convert all the
in-kernel users. The conversions are completely equivalent and
trivial.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: netdev@vger.kernel.org
Cc: Anton Vorontsov <cbou@mail.ru>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alex Elder <aelder@sgi.com>
Cc: xfs-masters@oss.sgi.com
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: netfilter-devel@vger.kernel.org
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: linux-nfs@vger.kernel.org
When an xprt is created, it has a refcount of 1, and XPT_BUSY is set.
The refcount is *not* owned by the thread that created the xprt
(as is clear from the fact that creators never put the reference).
Rather, it is owned by the absence of XPT_DEAD. Once XPT_DEAD is set,
(And XPT_BUSY is clear) that initial reference is dropped and the xprt
can be freed.
So when a creator clears XPT_BUSY it is dropping its only reference and
so must not touch the xprt again.
However svc_recv, after calling ->xpo_accept (and so getting an XPT_BUSY
reference on a new xprt), calls svc_xprt_recieved. This clears
XPT_BUSY and then svc_xprt_enqueue - this last without owning a reference.
This is dangerous and has been seen to leave svc_xprt_enqueue working
with an xprt containing garbage.
So we need to hold an extra counted reference over that call to
svc_xprt_received.
For safety, any time we clear XPT_BUSY and then use the xprt again, we
first get a reference, and the put it again afterwards.
Note that svc_close_all does not need this extra protection as there are
no threads running, and the final free can only be called asynchronously
from such a thread.
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If the rpcauth_refreshcred() call returns an error other than
EACCES, ENOMEM or ETIMEDOUT, we currently end up looping forever
between call_refresh and call_refreshresult.
The correct thing to do here is to exit on all errors except
EAGAIN and ETIMEDOUT, for which case we retry 3 times, then
return EACCES.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Stanislav Kinsbursky