Commit Graph

94 Commits

Author SHA1 Message Date
J. Bruce Fields d10f27a750 svcrpc: fix svc_xprt_enqueue/svc_recv busy-looping
The rpc server tries to ensure that there will be room to send a reply
before it receives a request.

It does this by tracking, in xpt_reserved, an upper bound on the total
size of the replies that is has already committed to for the socket.

Currently it is adding in the estimate for a new reply *before* it
checks whether there is space available.  If it finds that there is not
space, it then subtracts the estimate back out.

This may lead the subsequent svc_xprt_enqueue to decide that there is
space after all.

The results is a svc_recv() that will repeatedly return -EAGAIN, causing
server threads to loop without doing any actual work.

Cc: stable@vger.kernel.org
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Tested-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-08-20 18:39:19 -04:00
J. Bruce Fields f06f00a24d svcrpc: sends on closed socket should stop immediately
svc_tcp_sendto sets XPT_CLOSE if we fail to transmit the entire reply.
However, the XPT_CLOSE won't be acted on immediately.  Meanwhile other
threads could send further replies before the socket is really shut
down.  This can manifest as data corruption: for example, if a truncated
read reply is followed by another rpc reply, that second reply will look
to the client like further read data.

Symptoms were data corruption preceded by svc_tcp_sendto logging
something like

	kernel: rpc-srv/tcp: nfsd: sent only 963696 when sending 1048708 bytes - shutting down socket

Cc: stable@vger.kernel.org
Reported-by: Malahal Naineni <malahal@us.ibm.com>
Tested-by: Malahal Naineni <malahal@us.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-08-20 18:38:59 -04:00
Linus Torvalds 419f431949 Merge branch 'for-3.5' of git://linux-nfs.org/~bfields/linux
Pull the rest of the nfsd commits from Bruce Fields:
 "... and then I cherry-picked the remainder of the patches from the
  head of my previous branch"

This is the rest of the original nfsd branch, rebased without the
delegation stuff that I thought really needed to be redone.

I don't like rebasing things like this in general, but in this situation
this was the lesser of two evils.

* 'for-3.5' of git://linux-nfs.org/~bfields/linux: (50 commits)
  nfsd4: fix, consolidate client_has_state
  nfsd4: don't remove rebooted client record until confirmation
  nfsd4: remove some dprintk's and a comment
  nfsd4: return "real" sequence id in confirmed case
  nfsd4: fix exchange_id to return confirm flag
  nfsd4: clarify that renewing expired client is a bug
  nfsd4: simpler ordering of setclientid_confirm checks
  nfsd4: setclientid: remove pointless assignment
  nfsd4: fix error return in non-matching-creds case
  nfsd4: fix setclientid_confirm same_cred check
  nfsd4: merge 3 setclientid cases to 2
  nfsd4: pull out common code from setclientid cases
  nfsd4: merge last two setclientid cases
  nfsd4: setclientid/confirm comment cleanup
  nfsd4: setclientid remove unnecessary terms from a logical expression
  nfsd4: move rq_flavor into svc_cred
  nfsd4: stricter cred comparison for setclientid/exchange_id
  nfsd4: move principal name into svc_cred
  nfsd4: allow removing clients not holding state
  nfsd4: rearrange exchange_id logic to simplify
  ...
2012-06-01 08:32:58 -07:00
J. Bruce Fields 3ddbe8794f svcrpc: fix a comment typo
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-05-31 20:29:49 -04:00
Jeff Layton 91c427ac3a sunrpc: do array overrun check in svc_recv before allocating pages
There's little point in waiting until after we allocate all of the pages
to see if we're going to overrun the array. In the event that this
calculation is really off we could end up scribbling over a bunch of
memory and make it tougher to debug.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-05-31 20:29:41 -04:00
Joe Perches e87cc4728f net: Convert net_ratelimit uses to net_<level>_ratelimited
Standardize the net core ratelimited logging functions.

Coalesce formats, align arguments.
Change a printk then vprintk sequence to use printf extension %pV.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-15 13:45:03 -04:00
Stanislav Kinsbursky 7b147f1ff2 SUNRPC: service destruction in network namespace context
v2: Added comment to BUG_ON's in svc_destroy() to make code looks clearer.

This patch introduces network namespace filter for service destruction
function.
Nothing special here - just do exactly the same operations, but only for
tranports in passed networks namespace context.
BTW, BUG_ON() checks for empty service transports lists were returned into
svc_destroy() function. This is because of swithing generic svc_close_all() to
networks namespace dependable svc_close_net().

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-02-15 00:19:45 -05:00
Stanislav Kinsbursky 3a22bf506c SUNRPC: clear svc transports lists helper introduced
This patch moves service transports deletion from service sockets lists to
separated function.
This is a precursor patch, which would be usefull with service shutdown in
network namespace context, introduced later in the series.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-02-15 00:19:45 -05:00
Stanislav Kinsbursky 6f5133652e SUNRPC: clear svc pools lists helper introduced
This patch moves removing of service transport from it's pools ready lists to
separated function. Also this clear is now done with list_for_each_entry_safe()
helper.
This is a precursor patch, which would be usefull with service shutdown in
network namespace context, introduced later in the series.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-02-15 00:19:44 -05:00
Stanislav Kinsbursky 4cb54ca206 SUNRPC: search for service transports in network namespace context
Service transports are parametrized by network namespace. And thus lookup of
transport instance have to take network namespace into account.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
2012-01-31 19:28:19 -05:00
Linus Torvalds 0b48d42235 Merge branch 'for-3.3' of git://linux-nfs.org/~bfields/linux
* 'for-3.3' of git://linux-nfs.org/~bfields/linux: (31 commits)
  nfsd4: nfsd4_create_clid_dir return value is unused
  NFSD: Change name of extended attribute containing junction
  svcrpc: don't revert to SVC_POOL_DEFAULT on nfsd shutdown
  svcrpc: fix double-free on shutdown of nfsd after changing pool mode
  nfsd4: be forgiving in the absence of the recovery directory
  nfsd4: fix spurious 4.1 post-reboot failures
  NFSD: forget_delegations should use list_for_each_entry_safe
  NFSD: Only reinitilize the recall_lru list under the recall lock
  nfsd4: initialize special stateid's at compile time
  NFSd: use network-namespace-aware cache registering routines
  SUNRPC: create svc_xprt in proper network namespace
  svcrpc: update outdated BKL comment
  nfsd41: allow non-reclaim open-by-fh's in 4.1
  svcrpc: avoid memory-corruption on pool shutdown
  svcrpc: destroy server sockets all at once
  svcrpc: make svc_delete_xprt static
  nfsd: Fix oops when parsing a 0 length export
  nfsd4: Use kmemdup rather than duplicating its implementation
  nfsd4: add a separate (lockowner, inode) lookup
  nfsd4: fix CONFIG_NFSD_FAULT_INJECTION compile error
  ...
2012-01-14 12:26:41 -08:00
Eric Dumazet dfd56b8b38 net: use IS_ENABLED(CONFIG_IPV6)
Instead of testing defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-11 18:25:16 -05:00
Stanislav Kinsbursky bd4620ddf6 SUNRPC: create svc_xprt in proper network namespace
This patch makes svc_xprt inherit network namespace link from its socket.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-12-06 16:20:42 -05:00
J. Bruce Fields b4f36f88b3 svcrpc: avoid memory-corruption on pool shutdown
Socket callbacks use svc_xprt_enqueue() to add an xprt to a
pool->sp_sockets list.  In normal operation a server thread will later
come along and take the xprt off that list.  On shutdown, after all the
threads have exited, we instead manually walk the sv_tempsocks and
sv_permsocks lists to find all the xprt's and delete them.

So the sp_sockets lists don't really matter any more.  As a result,
we've mostly just ignored them and hoped they would go away.

Which has gotten us into trouble; witness for example ebc63e531c
"svcrpc: fix list-corrupting race on nfsd shutdown", the result of Ben
Greear noticing that a still-running svc_xprt_enqueue() could re-add an
xprt to an sp_sockets list just before it was deleted.  The fix was to
remove it from the list at the end of svc_delete_xprt().  But that only
made corruption less likely--I can see nothing that prevents a
svc_xprt_enqueue() from adding another xprt to the list at the same
moment that we're removing this xprt from the list.  In fact, despite
the earlier xpo_detach(), I don't even see what guarantees that
svc_xprt_enqueue() couldn't still be running on this xprt.

So, instead, note that svc_xprt_enqueue() essentially does:
	lock sp_lock
		if XPT_BUSY unset
			add to sp_sockets
	unlock sp_lock

So, if we do:

	set XPT_BUSY on every xprt.
	Empty every sp_sockets list, under the sp_socks locks.

Then we're left knowing that the sp_sockets lists are all empty and will
stay that way, since any svc_xprt_enqueue() will check XPT_BUSY under
the sp_lock and see it set.

And *then* we can continue deleting the xprt's.

(Thanks to Jeff Layton for being correctly suspicious of this code....)

Cc: Ben Greear <greearb@candelatech.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-12-06 16:18:58 -05:00
J. Bruce Fields 2fefb8a09e svcrpc: destroy server sockets all at once
There's no reason I can see that we need to call sv_shutdown between
closing the two lists of sockets.

Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-12-06 16:18:52 -05:00
J. Bruce Fields 7710ec36b6 svcrpc: make svc_delete_xprt static
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-12-06 16:18:51 -05:00
Paul Gortmaker 3a9a231d97 net: Fix files explicitly needing to include module.h
With calls to modular infrastructure, these files really
needs the full module.h header.  Call it out so some of the
cleanups of implicit and unrequired includes elsewhere can be
cleaned up.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:28 -04:00
Mi Jinlong 849a1cf13d SUNRPC: Replace svc_addr_u by sockaddr_storage
For IPv6 local address, lockd can not callback to client for
missing scope id when binding address at inet6_bind:

 324       if (addr_type & IPV6_ADDR_LINKLOCAL) {
 325               if (addr_len >= sizeof(struct sockaddr_in6) &&
 326                   addr->sin6_scope_id) {
 327                       /* Override any existing binding, if another one
 328                        * is supplied by user.
 329                        */
 330                       sk->sk_bound_dev_if = addr->sin6_scope_id;
 331               }
 332
 333               /* Binding to link-local address requires an interface */
 334               if (!sk->sk_bound_dev_if) {
 335                       err = -EINVAL;
 336                       goto out_unlock;
 337               }

Replacing svc_addr_u by sockaddr_storage, let rqstp->rq_daddr contains more info
besides address.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-09-14 08:21:48 -04:00
J. Bruce Fields ebc63e531c svcrpc: fix list-corrupting race on nfsd shutdown
After commit 3262c816a3 "[PATCH] knfsd:
split svc_serv into pools", svc_delete_xprt (then svc_delete_socket) no
longer removed its xpt_ready (then sk_ready) field from whatever list it
was on, noting that there was no point since the whole list was about to
be destroyed anyway.

That was mostly true, but forgot that a few svc_xprt_enqueue()'s might
still be hanging around playing with the about-to-be-destroyed list, and
could get themselves into trouble writing to freed memory if we left
this xprt on the list after freeing it.

(This is actually functionally identical to a patch made first by Ben
Greear, but with more comments.)

Cc: stable@kernel.org
Cc: gnb@fmeh.org
Reported-by: Ben Greear <greearb@candelatech.com>
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-07-15 18:58:46 -04:00
J. Bruce Fields 99de8ea962 rpc: keep backchannel xprt as long as server connection
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>
2011-01-11 15:04:10 -05:00
J. Bruce Fields 9e701c6109 svcrpc: simpler request dropping
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>
2011-01-04 16:49:22 -05:00
NeilBrown 7c96aef759 sunrpc: remove xpt_pool
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>
2010-12-17 15:48:18 -05:00
J. Bruce Fields ec66ee3797 Merge commit 'v2.6.37-rc6' into for-2.6.38 2010-12-17 13:29:07 -05:00
NeilBrown ed2849d3ec sunrpc: prevent use-after-free on clearing XPT_BUSY
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>
2010-12-07 20:39:55 -05:00
J. Bruce Fields 9c335c0b8d svcrpc: fix wspace-checking race
We call svc_xprt_enqueue() after something happens which we think may
require handling from a server thread.  To avoid such events being lost,
svc_xprt_enqueue() must guarantee that there will be a svc_serv() call
from a server thread following any such event.  It does that by either
waking up a server thread itself, or checking that XPT_BUSY is set (in
which case somebody else is doing it).

But the check of XPT_BUSY could occur just as someone finishes
processing some other event, and just before they clear XPT_BUSY.

Therefore it's important not to clear XPT_BUSY without subsequently
doing another svc_export_enqueue() to check whether the xprt should be
requeued.

The xpo_wspace() check in svc_xprt_enqueue() breaks this rule, allowing
an event to be missed in situations like:

	data arrives
	call svc_tcp_data_ready():
	call svc_xprt_enqueue():
	set BUSY
	find no write space
				svc_reserve():
				free up write space
				call svc_enqueue():
				test BUSY
	clear BUSY

So, instead, check wspace in the same places that the state flags are
checked: before taking BUSY, and in svc_receive().

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-11-19 18:35:12 -05:00
J. Bruce Fields b176331627 svcrpc: svc_close_xprt comment
Neil Brown had to explain to me why we do this here; record the answer
for posterity.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-11-19 18:35:12 -05:00
J. Bruce Fields f8c0d226fe svcrpc: simplify svc_close_all
There's no need to be fooling with XPT_BUSY now that all the threads
are gone.

The list_del_init() here could execute at the same time as the
svc_xprt_enqueue()'s list_add_tail(), with undefined results.  We don't
really care at this point, but it might result in a spurious
list-corruption warning or something.

And svc_close() isn't adding any value; just call svc_delete_xprt()
directly.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-11-19 18:35:11 -05:00
J. Bruce Fields ca7896cd83 nfsd4: centralize more calls to svc_xprt_received
Follow up on b48fa6b991 by moving all the
svc_xprt_received() calls for the main xprt to one place.  The clearing
of XPT_BUSY here is critical to the correctness of the server, so I'd
prefer it to be obvious where we do it.

The only substantive result is moving svc_xprt_received() after
svc_receive_deferred().  Other than a (likely insignificant) delay
waking up the next thread, that should be harmless.

Also reshuffle the exit code a little to skip a few other steps that we
don't care about the in the svc_delete_xprt() case.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-11-19 18:35:11 -05:00
J. Bruce Fields 62bac4af3d svcrpc: don't set then immediately clear XPT_DEFERRED
There's no harm to doing this, since the only caller will immediately
call svc_enqueue() afterwards, ensuring we don't miss the remaining
deferred requests just because XPT_DEFERRED was briefly cleared.

But why not just do this the simple way?

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-11-19 18:35:11 -05:00
Arnd Bergmann 451a3c24b0 BKL: remove extraneous #include <smp_lock.h>
The big kernel lock has been removed from all these files at some point,
leaving only the #include.

Remove this too as a cleanup.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-17 08:59:32 -08:00
J. Bruce Fields 01dba075d5 svcrpc: no need for XPT_DEAD check in svc_xprt_enqueue
If any xprt marked DEAD is also left BUSY for the rest of its life, then
the XPT_DEAD check here is superfluous--we'll get the same result from
the XPT_BUSY check just after.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-10-25 17:59:33 -04:00
J. Bruce Fields ac9303eb74 svcrpc: assume svc_delete_xprt() called only once
As long as DEAD exports are left BUSY, and svc_delete_xprt is called
only with BUSY held, then svc_delete_xprt() will never be called on an
xprt that is already DEAD.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-10-25 17:59:32 -04:00
J. Bruce Fields 7e4fdd0744 svcrpc: never clear XPT_BUSY on dead xprt
Once an xprt has been deleted, there's no reason to allow it to be
enqueued--at worst, that might cause the xprt to be re-added to some
global list, resulting in later corruption.

Also, note this leaves us with no need for the reference-count
manipulation here.

Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-10-25 17:58:40 -04:00
Pavel Emelyanov 8f3a6de313 sunrpc: Turn list_for_each-s into the ..._entry-s
Saves some lines of code and some branticks when reading one.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-10-19 10:48:16 -04:00
J. Bruce Fields edc7a89403 nfsd: provide callbacks on svc_xprt deletion
NFSv4.1 needs warning when a client tcp connection goes down, if that
connection is being used as a backchannel, so that it can warn the
client that it has lost the backchannel connection.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-10-01 19:29:44 -04:00
Pavel Emelyanov 62832c039e sunrpc: Pull net argument downto svc_create_socket
After this the socket creation in it knows the context.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-10-01 17:18:55 -04:00
Pavel Emelyanov fc5d00b04a sunrpc: Add net argument to svc_create_xprt
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-10-01 17:18:54 -04:00
Pavel Emelyanov 4fb8518bda sunrpc: Tag svc_xprt with net
The transport representation should be per-net of course.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-09-27 10:16:12 -04:00
Pavel Emelyanov e3bfca01c1 sunrpc: Make xprt auth cache release work with the xprt
This is done in order to facilitate getting the ip_map_cache from
which to put the ip_map.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-09-27 10:16:11 -04:00
J. Bruce Fields 6610f720e9 svcrpc: minor cache cleanup
Pull out some code into helper functions, fix a typo.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-09-07 20:19:12 -04:00
NeilBrown f16b6e8d83 sunrpc/cache: allow threads to block while waiting for cache update.
The current practice of waiting for cache updates by queueing the
whole request to be retried has (at least) two problems.

1/ With NFSv4, requests can be quite complex and re-trying a whole
  request when a later part fails should only be a last-resort, not a
  normal practice.

2/ Large requests, and in particular any 'write' request, will not be
  queued by the current code and doing so would be undesirable.

In many cases only a very sort wait is needed before the cache gets
valid data.

So, providing the underlying transport permits it by setting
 ->thread_wait,
arrange to wait briefly for an upcall to be completed (as reflected in
the clearing of CACHE_PENDING).
If the short wait was not long enough and CACHE_PENDING is still set,
fall back on the old approach.

The 'thread_wait' value is set to 5 seconds when there are spare
threads, and 1 second when there are no spare threads.

These values are probably much higher than needed, but will ensure
some forward progress.

Note that as we only request an update for a non-valid item, and as
non-valid items are updated in place it is extremely unlikely that
cache_check will return -ETIMEDOUT.  Normally cache_defer_req will
sleep for a short while and then find that the item is_valid.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2010-09-07 19:22:07 -04:00
J. Bruce Fields 5306293c9c Merge commit 'v2.6.34-rc6'
Conflicts:
	fs/nfsd/nfs4callback.c
2010-05-04 11:29:05 -04:00
Neil Brown b48fa6b991 sunrpc: centralise most calls to svc_xprt_received
svc_xprt_received must be called when ->xpo_recvfrom has finished
receiving a message, so that the XPT_BUSY flag will be cleared and
if necessary, requeued for further work.

This call is currently made in each ->xpo_recvfrom function, often
from multiple different points.  In each case it is the earliest point
on a particular path where it is known that the protection provided by
XPT_BUSY is no longer needed.

However there are (still) some error paths which do not call
svc_xprt_received, and requiring each ->xpo_recvfrom to make the call
does not encourage robustness.

So: move the svc_xprt_received call to be made just after the
call to ->xpo_recvfrom(), and move it of the various ->xpo_recvfrom
methods.

This means that it may not be called at the earliest possible instant,
but this is unlikely to be a measurable performance issue.

Note that there are still other calls to svc_xprt_received as it is
also needed when an xprt is newly created.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-05-03 08:33:00 -04:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
J. Bruce Fields 788e69e548 svcrpc: don't hold sv_lock over svc_xprt_put()
svc_xprt_put() can call tcp_close(), which can sleep, so we shouldn't be
holding this lock.

In fact, only the xpt_list removal and the sv_tmpcnt decrement should
need the sv_lock here.

Reported-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-29 21:02:31 -04:00
J. Bruce Fields 1b644b6e6f Revert "sunrpc: move the close processing after do recvfrom method"
This reverts commit b0401d7253, which
moved svc_delete_xprt() outside of XPT_BUSY, and allowed it to be called
after svc_xpt_recived(), removing its last reference and destroying it
after it had already been queued for future processing.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-02-28 16:39:30 -05:00
J. Bruce Fields f5822754ea Revert "sunrpc: fix peername failed on closed listener"
This reverts commit b292cf9ce7.  The
commit that it attempted to patch up,
b0401d7253, was fundamentally wrong, and
will also be reverted.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-02-28 16:39:15 -05:00
Neil Brown ab1b18f70a sunrpc: remove unnecessary svc_xprt_put
The 'struct svc_deferred_req's on the xpt_deferred queue do not
own a reference to the owning xprt.  This is seen in svc_revisit
which is where things are added to this queue.  dr->xprt is set to
NULL and the reference to the xprt it put.

So when this list is cleaned up in svc_delete_xprt, we mustn't
put the reference.

Also, replace the 'for' with a 'while' which is arguably
simpler and more likely to compile efficiently.

Cc: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-02-26 17:42:46 -05:00
Chuck Lever 6871790815 SUNRPC: NFS kernel APIs shouldn't return ENOENT for "transport not found"
write_ports() converts svc_create_xprt()'s ENOENT error return to
EPROTONOSUPPORT so that rpc.nfsd (in user space) can report an error
message that makes sense.

It turns out that several of the other kernel APIs rpc.nfsd use can
also return ENOENT from svc_create_xprt(), by way of lockd_up().

On the client side, an NFSv2 or NFSv3 mount request can also return
the result of lockd_up().  This error may also be returned during an
NFSv4 mount request, since the NFSv4 callback service uses
svc_create_xprt() to create the callback listener.  An ENOENT error
return results in a confusing error message from the mount command.

Let's have svc_create_xprt() return EPROTONOSUPPORT instead of ENOENT.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-26 17:59:21 -05:00
Chuck Lever d6783b2b6c SUNRPC: Bury "#ifdef IPV6" in svc_create_xprt()
Clean up:  Bruce observed we have more or less common logic in each of
svc_create_xprt()'s callers:  the check to create an IPv6 RPC listener
socket only if CONFIG_IPV6 is set.  I'm about to add another case
that does just the same.

If we move the ifdefs into __svc_xpo_create(), then svc_create_xprt()
call sites can get rid of the "#ifdef" ugliness, and can use the same
logic with or without IPv6 support available in the kernel.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-26 17:56:43 -05:00