2137 Commits

Author SHA1 Message Date
Stanislav Kinsbursky
cd6c596858 SUNRPC: continue run over clients list on PipeFS event instead of break
There are SUNRPC clients, which program doesn't have pipe_dir_name. These
clients can be skipped on PipeFS events, because nothing have to be created or
destroyed. But instead of breaking in case of such a client was found, search
for suitable client over clients list have to be continued. Otherwise some
clients could not be covered by PipeFS event handler.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org [>= v3.4]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-17 12:19:16 -05:00
Trond Myklebust
1efc28780b SUNRPC: variable 'svsk' is unused in function bc_send_request
Silence a compile time warning.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-15 17:05:57 -05:00
Trond Myklebust
4a20a988f7 SUNRPC: Handle ECONNREFUSED in xs_local_setup_socket
Silence the unnecessary warning "unhandled error (111) connecting to..."
and convert it to a dprintk for debugging purposes.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-15 17:02:29 -05:00
Andy Adamson
eb96d5c97b SUNRPC handle EKEYEXPIRED in call_refreshresult
Currently, when an RPCSEC_GSS context has expired or is non-existent
and the users (Kerberos) credentials have also expired or are non-existent,
the client receives the -EKEYEXPIRED error and tries to refresh the context
forever.  If an application is performing I/O, or other work against the share,
the application hangs, and the user is not prompted to refresh/establish their
credentials. This can result in a denial of service for other users.

Users are expected to manage their Kerberos credential lifetimes to mitigate
this issue.

Move the -EKEYEXPIRED handling into the RPC layer. Try tk_cred_retry number
of times to refresh the gss_context, and then return -EACCES to the application.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-12 15:36:02 -05:00
Andy Adamson
620038f6d2 SUNRPC set gss gc_expiry to full lifetime
Only use the default GSSD_MIN_TIMEOUT if the gss downcall timeout is zero.
Store the full lifetime in gc_expiry (not 3/4 of the lifetime) as subsequent
patches will use the gc_expiry to determine buffered WRITE behavior in the
face of expired or soon to be expired gss credentials.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-12 15:35:59 -05:00
Trond Myklebust
7ce0171d4f Merge branch 'bugfixes' into nfs-for-next 2012-12-11 09:16:26 -05:00
Stanislav Kinsbursky
756933ee8a SUNRPC: remove redundant "linux/nsproxy.h" includes
This is a cleanup patch.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-12-10 16:25:30 -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
J. Bruce Fields
836fbadb96 svcrpc: support multiple-fragment rpc's
Over TCP, RPC's are preceded by a single 4-byte field telling you how
long the rpc is (in bytes).  The spec also allows you to send an RPC in
multiple such records (the high bit of the length field is used to tell
you whether this is the final record).

We've survived for years without supporting this because in practice the
clients we care about don't use it.  But the userland rpc libraries do,
and every now and then an experimental client will run into this.  (Most
recently I noticed it while trying to write a pynfs check.)  And we're
really on the wrong side of the spec here--let's fix this.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-12-04 07:49:24 -05:00
J. Bruce Fields
8af345f58a svcrpc: track rpc data length separately from sk_tcplen
Keep a separate field, sk_datalen, that tracks only the data contained
in a fragment, not including the fragment header.

For now, this is always just max(0, sk_tcplen - 4), but after we allow
multiple fragments sk_datalen will accumulate the total rpc data size
while sk_tcplen only tracks progress receiving the current fragment.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-12-04 07:49:14 -05:00
J. Bruce Fields
6a72ae2e23 svcrpc: fix off-by-4 error in "incomplete TCP record" dprintk
The full reclen doesn't include the fragment header, but sk_tcplen does.
Fix this to make it an apples-to-apples comparison.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-12-04 07:49:06 -05:00
J. Bruce Fields
ad46ccf094 svcrpc: delay minimum-rpc-size check till later
Soon we want to support multiple fragments, in which case it may be
legal for a single fragment to be smaller than 8 bytes, so we'll want to
delay this check till we've reached the last fragment.

Also fix an outdated comment.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-12-04 07:47:58 -05:00
J. Bruce Fields
cc248d4b1d svcrpc: don't byte-swap sk_reclen in place
Byte-swapping in place is always a little dubious.

Let's instead define this field to always be big-endian, and do the
swapping on demand where we need it.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-12-04 07:47:23 -05:00
Trond Myklebust
642fe4d00d SUNRPC: Fix validity issues with rpc_pipefs sb->s_fs_info
rpc_kill_sb() must defer calling put_net() until after the notifier
has been called, since most (all?) of the notifier callbacks assume
that sb->s_fs_info points to a valid net namespace. It also must not
call put_net() if the call to rpc_fill_super was unsuccessful.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=48421

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org [>= v3.4]
2012-11-08 14:53:28 -05:00
J. Bruce Fields
7032a3dd92 svcrpc: demote some printks to a dprintk
In general I'd rather random bad behavior on the network won't trigger a
printk.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-11-07 19:31:32 -05:00
Trond Myklebust
f994c43d19 SUNRPC: Clean up rpc_bind_new_program
We can and should use the rpc_create_args and __rpc_clone_client()
to change the program and version number on the resulting rpc_client.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:43 -05:00
Weston Andros Adamson
50d2bdb197 SUNRPC: remove BUG_ON from rpc_call_sync
Use WARN_ON_ONCE instead of calling BUG_ON and return -EINVAL when
RPC_TASK_ASYNC flag is passed to rpc_call_sync.

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
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
0104729807 SUNRPC: remove BUG_ON in svc_delete_xprt
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
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
0af39507f6 SUNRPC: remove BUG_ON in svc_register
Instead of calling BUG_ON(), do a WARN_ON_ONCE() and return -EINVAL.

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
332e008a44 SUNRPC: remove BUG_ON from encode_rpcb_string
Replace BUG_ON() with WARN_ON_ONCE() and truncate the encoded string if
len > max.

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
b8a13d039c SUNRPC: remove BUG_ON from bc_malloc
Replace BUG_ON() with WARN_ON_ONCE() and NULL return - the caller will handle
this like a memory allocation failure.

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
18e624ad03 SUNRPC: remove BUG_ON in xdr_shrink_bufhead
Replace bounds checking BUG_ON() with a WARN_ON_ONCE() and resetting
the requested len to the max.

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
b25cd058f2 SUNRPC: remove BUG_ONs checking RPCSVC_MAXPAGES
Replace two bounds checking BUG_ON() calls with WARN_ON_ONCE() and resetting
the requested size to RPCSVC_MAXPAGES.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:41 -05:00
Weston Andros Adamson
ff1fdb9b80 SUNRPC: remove BUG_ON in svc_xprt_received
Replace BUG_ON() with a WARN_ON_ONCE() and early return.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:41 -05:00
Weston Andros Adamson
1b7a181907 SUNRPC: remove BUG_ONs from *_reclassify_socket*
Replace multiple BUG_ON() calls with WARN_ON_ONCE() and early return when
sanity checking socket ownership (lock). The bind call will fail if the
socket was unsuccessfully reclassified.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:41 -05:00
Weston Andros Adamson
1bd58aaff4 SUNRPC: remove BUG_ON from svc_pool_map_set_cpumask
Replace BUG_ON() with a WARN() and early return.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:41 -05:00
Weston Andros Adamson
f30dfbba16 SUNRPC: remove two BUG_ON asserts
Replace two BUG_ON() calls checking the RPC_BC_PA_IN_USE flag 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 14:43:41 -05:00
Weston Andros Adamson
749386e906 SUNRPC: remove BUG_ON in rpc_put_sb_net
Replace BUG_ON() with WARN_ON() - the condition is definitely a misuse
of the API, but shouldn't cause a crash.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:41 -05:00
Weston Andros Adamson
0db74d9a2d SUNRPC: remove BUG_ON calls from cache_read
Replace BUG_ON() with WARN_ON_ONCE() in two parts of cache_read().

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:41 -05:00
Weston Andros Adamson
4c9c52e479 SUNRPC: remove BUG_ON from bc_send
Replace BUG_ON() with WARN_ON_ONCE(). The error condition is a simple
ref counting sanity check and the following code will not free anything
until final put.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:41 -05:00
Weston Andros Adamson
c4ded8d977 SUNRPC: remove BUG_ON from xprt_destroy_backchannel
If max_reqs is 0, do nothing besides the usual dprintks.

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
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
Weston Andros Adamson
8b827e1f1e SUNRPC: remove BUG_ON from call_bc_transmit
Remove redundant BUG_ON().

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
Weston Andros Adamson
1facf4c4a4 SUNRPC: remove BUG_ON from call_bc_transmit
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 14:43:40 -05:00
Weston Andros Adamson
576e613d21 SUNRPC: remove BUG_ON from call_transmit
Remove unneeded BUG_ON()

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
Weston Andros Adamson
9a6478f6cc SUNRPC: remove BUG_ON from rpc_run_bc_task
Replace BUG_ON() with WARN_ON_ONCE() - rpc_run_bc_task calls rpc_init_task()
then increments the tk_count, so this is a simple sanity check that
if hit once would hit every time this code path is executed.

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
Weston Andros Adamson
922eeac30d SUNRPC: remove BUG_ON in __rpc_clnt_handle_event
Print a KERN_INFO message before rpc_d_lookup_sb returns NULL, like
other error paths in that function.

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
Weston Andros Adamson
168e4b39d1 SUNRPC: add WARN_ON_ONCE for potential deadlock
rpc_shutdown_client should never be called from a workqueue context.
If it is, it could deadlock looping forever trying to kill tasks that are
assigned to the same kworker thread (and will never run rpc_exit_task).

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-04 14:43:38 -05:00
Weston Andros Adamson
d24bab93e4 SUNRPC: return proper errno from backchannel_rqst
The one and only caller (in fs/nfs/nfs4client.c) uses the result
as an errno and would have interpreted an error as EPERM.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-11-01 11:50:53 -04:00
Trond Myklebust
f878b657ce SUNRPC: Get rid of the xs_error_report socket callback
Chris Perl reports that we're seeing races between the wakeup call in
xs_error_report and the connect attempts. Basically, Chris has shown
that in certain circumstances, the call to xs_error_report causes the
rpc_task that is responsible for reconnecting to wake up early, thus
triggering a disconnect and retry.

Since the sk->sk_error_report() calls in the socket layer are always
followed by a tcp_done() in the cases where we care about waking up
the rpc_tasks, just let the state_change callbacks take responsibility
for those wake ups.

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>
2012-10-24 10:46:15 -04:00
Trond Myklebust
4bc1e68ed6 SUNRPC: Prevent races in xs_abort_connection()
The call to xprt_disconnect_done() that is triggered by a successful
connection reset will trigger another automatic wakeup of all tasks
on the xprt->pending rpc_wait_queue. In particular it will cause an
early wake up of the task that called xprt_connect().

All we really want to do here is clear all the socket-specific state
flags, so we split that functionality out of xs_sock_mark_closed()
into a helper that can be called by xs_abort_connection()

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>
2012-10-24 10:46:08 -04:00
Trond Myklebust
b9d2bb2ee5 Revert "SUNRPC: Ensure we close the socket on EPIPE errors too..."
This reverts commit 55420c24a0d4d1fce70ca713f84aa00b6b74a70e.
Now that we clear the connected flag when entering TCP_CLOSE_WAIT,
the deadlock described in this commit is no longer possible.
Instead, the resulting call to xs_tcp_shutdown() can interfere
with pending reconnection attempts.

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>
2012-10-24 10:45:39 -04:00
Trond Myklebust
d0bea455dd SUNRPC: Clear the connect flag when socket state is TCP_CLOSE_WAIT
This is needed to ensure that we call xprt_connect() upon the next
call to call_connect().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>
2012-10-24 10:44:49 -04:00
Sasha Levin
212ba90696 SUNRPC: Prevent kernel stack corruption on long values of flush
The buffer size in read_flush() is too small for the longest possible values
for it. This can lead to a kernel stack corruption:

[   43.047329] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff833e64b4
[   43.047329]
[   43.049030] Pid: 6015, comm: trinity-child18 Tainted: G        W    3.5.0-rc7-next-20120716-sasha #221
[   43.050038] Call Trace:
[   43.050435]  [<ffffffff836c60c2>] panic+0xcd/0x1f4
[   43.050931]  [<ffffffff833e64b4>] ? read_flush.isra.7+0xe4/0x100
[   43.051602]  [<ffffffff810e94e6>] __stack_chk_fail+0x16/0x20
[   43.052206]  [<ffffffff833e64b4>] read_flush.isra.7+0xe4/0x100
[   43.052951]  [<ffffffff833e6500>] ? read_flush_pipefs+0x30/0x30
[   43.053594]  [<ffffffff833e652c>] read_flush_procfs+0x2c/0x30
[   43.053596]  [<ffffffff812b9a8c>] proc_reg_read+0x9c/0xd0
[   43.053596]  [<ffffffff812b99f0>] ? proc_reg_write+0xd0/0xd0
[   43.053596]  [<ffffffff81250d5b>] do_loop_readv_writev+0x4b/0x90
[   43.053596]  [<ffffffff81250fd6>] do_readv_writev+0xf6/0x1d0
[   43.053596]  [<ffffffff812510ee>] vfs_readv+0x3e/0x60
[   43.053596]  [<ffffffff812511b8>] sys_readv+0x48/0xb0
[   43.053596]  [<ffffffff8378167d>] system_call_fastpath+0x1a/0x1f

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2012-10-17 14:59:10 -04:00
Linus Torvalds
bd81ccea85 Merge branch 'for-3.7' of git://linux-nfs.org/~bfields/linux
Pull nfsd update from J Bruce Fields:
 "Another relatively quiet cycle.  There was some progress on my
  remaining 4.1 todo's, but a couple of them were just of the form
  "check that we do X correctly", so didn't have much affect on the
  code.

  Other than that, a bunch of cleanup and some bugfixes (including an
  annoying NFSv4.0 state leak and a busy-loop in the server that could
  cause it to peg the CPU without making progress)."

* 'for-3.7' of git://linux-nfs.org/~bfields/linux: (46 commits)
  UAPI: (Scripted) Disintegrate include/linux/sunrpc
  UAPI: (Scripted) Disintegrate include/linux/nfsd
  nfsd4: don't allow reclaims of expired clients
  nfsd4: remove redundant callback probe
  nfsd4: expire old client earlier
  nfsd4: separate session allocation and initialization
  nfsd4: clean up session allocation
  nfsd4: minor free_session cleanup
  nfsd4: new_conn_from_crses should only allocate
  nfsd4: separate connection allocation and initialization
  nfsd4: reject bad forechannel attrs earlier
  nfsd4: enforce per-client sessions/no-sessions distinction
  nfsd4: set cl_minorversion at create time
  nfsd4: don't pin clientids to pseudoflavors
  nfsd4: fix bind_conn_to_session xdr comment
  nfsd4: cast readlink() bug argument
  NFSD: pass null terminated buf to kstrtouint()
  nfsd: remove duplicate init in nfsd4_cb_recall
  nfsd4: eliminate redundant nfs4_free_stateid
  fs/nfsd/nfs4idmap.c: adjust inconsistent IS_ERR and PTR_ERR
  ...
2012-10-13 10:53:54 +09:00
J. Bruce Fields
a9ca4043d0 Merge Trond's bugfixes
Merge branch 'bugfixes' of git://linux-nfs.org/~trondmy/nfs-2.6 into
for-3.7-incoming.  Mainly needed for Bryan's "SUNRPC: Set alloc_slot for
backchannel tcp ops", without which the 4.1 server oopses.
2012-10-11 12:41:05 -04:00