sunrpc: add a struct rpc_stats arg to rpc_create_args

We want to be able to have our rpc stats handled in a per network
namespace manner, so add an option to rpc_create_args to specify a
different rpc_stats struct instead of using the one on the rpc_program.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4.1: Use the nfs_client's rpc timeouts for backchannel

For backchannel requests that lookup the appropriate nfs_client, use the
state-management rpc_clnt's rpc_timeout parameters for the backchannel's
response. When the nfs_client cannot be found, fall back to using the
xprt's default timeout parameters.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Create a helper function for accessing the rpc_clnt's xprt_switch

This function takes the necessary rcu read lock to dereference the
client's rpc_xprt_switch and bump the reference count so it doesn't
disappear underneath us before returning. This does mean that callers
are responsible for calling xprt_switch_put() on the returned object
when they are done with it.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Remove unused function rpc_clnt_xprt_switch_put()

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Clean up unused variable in rpc_xprt_probe_trunked()

We don't use the rpc_xprt_switch anywhere in this function, so let's not
take an extra reference to in unnecessarily.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Replace strlcpy() with strscpy()

strlcpy() reads the entire source buffer first. This read may exceed
the destination size limit. This is both inefficient and can lead
to linear read overflows if a source string is not NUL-terminated[1].
Additionally, it returns the size of the source string, not the
resulting size of the destination string. In an effort to remove strlcpy()
completely[2], replace strlcpy() here with strscpy().

Explicitly handle the truncation case by returning the size of the
resulting string.

If "nodename" was ever longer than sizeof(clnt->cl_nodename) - 1, this
change will fix a bug where clnt->cl_nodelen would end up thinking there
were more characters in clnt->cl_nodename than there actually were,
which might have lead to kernel memory content exposures.

Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [1]
Link: https://github.com/KSPP/linux/issues/89 [2]
Co-developed-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20231114175407.work.410-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

SUNRPC: Fix RPC client cleaned up the freed pipefs dentries

RPC client pipefs dentries cleanup is in separated rpc_remove_pipedir()
workqueue,which takes care about pipefs superblock locking.
In some special scenarios, when kernel frees the pipefs sb of the
current client and immediately alloctes a new pipefs sb,
rpc_remove_pipedir function would misjudge the existence of pipefs
sb which is not the one it used to hold. As a result,
the rpc_remove_pipedir would clean the released freed pipefs dentries.

To fix this issue, rpc_remove_pipedir should check whether the
current pipefs sb is consistent with the original pipefs sb.

This error can be catched by KASAN:
=========================================================
[ 250.497700] BUG: KASAN: slab-use-after-free in dget_parent+0x195/0x200
[ 250.498315] Read of size 4 at addr ffff88800a2ab804 by task kworker/0:18/106503
[ 250.500549] Workqueue: events rpc_free_client_work
[ 250.501001] Call Trace:
[ 250.502880] kasan_report+0xb6/0xf0
[ 250.503209] ? dget_parent+0x195/0x200
[ 250.503561] dget_parent+0x195/0x200
[ 250.503897] ? __pfx_rpc_clntdir_depopulate+0x10/0x10
[ 250.504384] rpc_rmdir_depopulate+0x1b/0x90
[ 250.504781] rpc_remove_client_dir+0xf5/0x150
[ 250.505195] rpc_free_client_work+0xe4/0x230
[ 250.505598] process_one_work+0x8ee/0x13b0
...
[ 22.039056] Allocated by task 244:
[ 22.039390] kasan_save_stack+0x22/0x50
[ 22.039758] kasan_set_track+0x25/0x30
[ 22.040109] __kasan_slab_alloc+0x59/0x70
[ 22.040487] kmem_cache_alloc_lru+0xf0/0x240
[ 22.040889] __d_alloc+0x31/0x8e0
[ 22.041207] d_alloc+0x44/0x1f0
[ 22.041514] __rpc_lookup_create_exclusive+0x11c/0x140
[ 22.041987] rpc_mkdir_populate.constprop.0+0x5f/0x110
[ 22.042459] rpc_create_client_dir+0x34/0x150
[ 22.042874] rpc_setup_pipedir_sb+0x102/0x1c0
[ 22.043284] rpc_client_register+0x136/0x4e0
[ 22.043689] rpc_new_client+0x911/0x1020
[ 22.044057] rpc_create_xprt+0xcb/0x370
[ 22.044417] rpc_create+0x36b/0x6c0
...
[ 22.049524] Freed by task 0:
[ 22.049803] kasan_save_stack+0x22/0x50
[ 22.050165] kasan_set_track+0x25/0x30
[ 22.050520] kasan_save_free_info+0x2b/0x50
[ 22.050921] __kasan_slab_free+0x10e/0x1a0
[ 22.051306] kmem_cache_free+0xa5/0x390
[ 22.051667] rcu_core+0x62c/0x1930
[ 22.051995] __do_softirq+0x165/0x52a
[ 22.052347]
[ 22.052503] Last potentially related work creation:
[ 22.052952] kasan_save_stack+0x22/0x50
[ 22.053313] __kasan_record_aux_stack+0x8e/0xa0
[ 22.053739] __call_rcu_common.constprop.0+0x6b/0x8b0
[ 22.054209] dentry_free+0xb2/0x140
[ 22.054540] __dentry_kill+0x3be/0x540
[ 22.054900] shrink_dentry_list+0x199/0x510
[ 22.055293] shrink_dcache_parent+0x190/0x240
[ 22.055703] do_one_tree+0x11/0x40
[ 22.056028] shrink_dcache_for_umount+0x61/0x140
[ 22.056461] generic_shutdown_super+0x70/0x590
[ 22.056879] kill_anon_super+0x3a/0x60
[ 22.057234] rpc_kill_sb+0x121/0x200

Fixes: 0157d021d23a ("SUNRPC: handle RPC client pipefs dentries by network namespace aware routines")
Signed-off-by: felix <fuzhen5@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't skip timeout checks in call_connect_status()

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: ECONNRESET might require a rebind

If connect() is returning ECONNRESET, it usually means that nothing is
listening on that port. If so, a rebind might be required in order to
obtain the new port on which the RPC service is listening.

Fixes: fd01b2597941 ("SUNRPC: ECONNREFUSED should cause a rebind.")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Revert "SUNRPC dont update timeout value on connection reset"

This reverts commit 88428cc4ae7abcc879295fbb19373dd76aad2bdd.

The problem this commit is intended to fix was comprehensively fixed
in commit 7de62bc09fe6 ("SUNRPC dont update timeout value on connection
reset").
Since then, this commit has been preventing the correct timeout of soft
mounted requests.

Cc: stable@vger.kernel.org # 5.9.x: 09252177d5f9: SUNRPC: Handle major timeout in xprt_adjust_timeout()
Cc: stable@vger.kernel.org # 5.9.x: 7de62bc09fe6: SUNRPC dont update timeout value on connection reset
Cc: stable@vger.kernel.org # 5.9.x
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fail quickly when server does not recognize TLS

rpcauth_checkverf() should return a distinct error code when a
server recognizes the AUTH_TLS probe but does not support TLS so
that the client's header decoder can respond appropriately and
quickly. No retries are necessary is in this case, since the server
has already affirmatively answered "TLS is unsupported".

Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4.1: fix pnfs MDS=DS session trunking

Currently, when GETDEVICEINFO returns multiple locations where each
is a different IP but the server's identity is same as MDS, then
nfs4_set_ds_client() finds the existing nfs_client structure which
has the MDS's max_connect value (and if it's 1), then the 1st IP
on the DS's list will get dropped due to MDS trunking rules. Other
IPs would be added as they fall under the pnfs trunking rules.

For the list of IPs the 1st goes thru calling nfs4_set_ds_client()
which will eventually call nfs4_add_trunk() and call into
rpc_clnt_test_and_add_xprt() which has the check for MDS trunking.
The other IPs (after the 1st one), would call rpc_clnt_add_xprt()
which doesn't go thru that check.

nfs4_add_trunk() is called when MDS trunking is happening and it
needs to enforce the usage of max_connect mount option of the
1st mount. However, this shouldn't be applied to pnfs flow.

Instead, this patch proposed to treat MDS=DS as DS trunking and
make sure that MDS's max_connect limit does not apply to the
1st IP returned in the GETDEVICEINFO list. It does so by
marking the newly created client with a new flag NFS_CS_PNFS
which then used to pass max_connect value to use into the
rpc_clnt_test_and_add_xprt() instead of the existing rpc
client's max_connect value set by the MDS connection.

For example, mount was done without max_connect value set
so MDS's rpc client has cl_max_connect=1. Upon calling into
rpc_clnt_test_and_add_xprt() and using rpc client's value,
the caller passes in max_connect value which is previously
been set in the pnfs path (as a part of handling
GETDEVICEINFO list of IPs) in nfs4_set_ds_client().

However, when NFS_CS_PNFS flag is not set and we know we
are doing MDS trunking, comparing a new IP of the same
server, we then set the max_connect value to the
existing MDS's value and pass that into
rpc_clnt_test_and_add_xprt().

Fixes: dc48e0abee24 ("SUNRPC enforce creation of no more than max_connect xprts")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Revert "SUNRPC: Fail faster on bad verifier"

This reverts commit 0701214cd6e66585a999b132eb72ae0489beb724.

The premise of this commit was incorrect. There are exactly 2 cases
where rpcauth_checkverf() will return an error:

1) If there was an XDR decode problem (i.e. garbage data).
2) If gss_validate() had a problem verifying the RPCSEC_GSS MIC.

In the second case, there are again 2 subcases:

a) The GSS context expires, in which case gss_validate() will force a
new context negotiation on retry by invalidating the cred.
b) The sequence number check failed because an RPC call timed out, and
the client retransmitted the request using a new sequence number,
as required by RFC2203.

In neither subcase is this a fatal error.

Reported-by: Russell Cattelan <cattelan@thebarn.com>
Fixes: 0701214cd6e6 ("SUNRPC: Fail faster on bad verifier")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Mark the cred for revalidation if the server rejects it

If the server rejects the credential as being stale, or bad, then we
should mark it for revalidation before retransmitting.

Fixes: 7f5667a5f8c4 ("SUNRPC: Clean up rpc_verify_header()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Don't override connect timeouts in rpc_clnt_add_xprt()

If the caller specifies the connect timeouts in the arguments to
rpc_clnt_add_xprt(), then we shouldn't override them.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Allow specification of TCP client connect timeout at setup

When we create a TCP transport, the connect timeout parameters are
currently fixed to be 90s. This is problematic in the pNFS flexfiles
case, where we may have multiple mirrors, and we would like to fail over
quickly to the next mirror if a data server is down.

This patch adds the ability to specify the connection parameters at RPC
client creation time.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: kmap() the xdr pages during decode

If the pages are in HIGHMEM then we need to make sure they're mapped
before trying to read data off of them, otherwise we could end up with a
NULL pointer dereference.

The downside to this is that we need an extra cleanup step at the end of
decode to kunmap() the last page. I introduced an xdr_finish_decode()
function to do this. Right now this function only calls the
unmap_current_page() function, but other generic cleanup steps could be
added in the future if we come across anything else.

Reported-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS: add sysfs shutdown knob

Within each nfs_server sysfs tree, add an entry named "shutdown". Writing
1 to this file will set the cl_shutdown bit on the rpc_clnt structs
associated with that mount. If cl_shutdown is set, the task scheduler
immediately returns -EIO for new tasks.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Add RPC client support for the RPC_AUTH_TLS auth flavor

The new authentication flavor is used only to discover peer support
for RPC-over-TLS.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Trace the rpc_create_args

Pass the upper layer's rpc_create_args to the rpc_clnt_new()
tracepoint so additional parts of the upper layer's request can be
recorded.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Plumb an API for setting transport layer security

Add an initial set of policies along with fields for upper layers to
pass the requested policy down to the transport layer.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: support abstract unix socket addresses

An "abtract" address for an AF_UNIX socket start with a nul and can
contain any bytes for the given length, but traditionally doesn't
contain other nuls. When reported, the leading nul is replaced by '@'.

sunrpc currently rejects connections to these addresses and reports them
as an empty string. To provide support for future use of these
addresses, allow them for outgoing connections and report them more
usefully.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: remove the maximum number of retries in call_bind_status

Currently call_bind_status places a hard limit of 3 to the number of
retries on EACCES error. This limit was done to prevent NLM unlock
requests from being hang forever when the server keeps returning garbage.
However this change causes problem for cases when NLM service takes
longer than 9 seconds to register with the port mapper after a restart.

This patch removes this hard coded limit and let the RPC handles
the retry based on the standard hard/soft task semantics.

Fixes: 0b760113a3a1 ("NLM: Don't hang forever on NLM unlock requests")
Reported-by: Helen Chao <helen.chao@oracle.com>
Tested-by: Helen Chao <helen.chao@oracle.com>
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS: fix disabling of swap

When swap is activated to a file on an NFSv4 mount we arrange that the
state manager thread is always present as starting a new thread requires
memory allocations that might block waiting for swap.

Unfortunately the code for allowing the state manager thread to exit when
swap is disabled was not tested properly and does not work.
This can be seen by examining /proc/fs/nfsfs/servers after disabling swap
and unmounting the filesystem. The servers file will still list one
entry. Also a "ps" listing will show the state manager thread is still
present.

There are two problems.
1/ rpc_clnt_swap_deactivate() doesn't walk up the ->cl_parent list to
find the primary client on which the state manager runs.

2/ The thread is not woken up properly and it immediately goes back to
sleep without checking whether it is really needed. Using
nfs4_schedule_state_manager() ensures a proper wake-up.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 4dc73c679114 ("NFSv4: keep state manager thread active if swap is enabled")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix missing release socket in rpc_sockname()

socket dynamically created is not released when getting an unintended
address family type in rpc_sockname(), direct to out_release for calling
sock_release().

Fixes: 2e738fdce22f ("SUNRPC: Add API to acquire source address")
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Add API to force the client to disconnect

Allow the caller to force a disconnection of the RPC client so that we
can clear any pending requests that are buffered in the socket.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add a helper to allow pNFS drivers to selectively cancel RPC calls

Add the helper rpc_cancel_tasks(), which uses a caller-defined selection
function to define a set of in-flight RPC calls to cancel. This is
mainly intended for pNFS drivers which are subject to a layout recall,
and which may therefore want to cancel all pending I/O using that layout
in order to redrive it after the layout recall has been satisfied.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix races with rpc_killall_tasks()

Ensure that we immediately call rpc_exit_task() after waking up, and
that the tk_rpc_status cannot get clobbered by some other function.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Directly use ida_alloc()/free()

Use ida_alloc()/ida_free() instead of
ida_simple_get()/ida_simple_remove().
The latter is deprecated and more verbose.

Signed-off-by: Bo Liu <liubo03@inspur.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Revert "SUNRPC: Remove unreachable error condition"

This reverts commit efe57fd58e1cb77f9186152ee12a8aa4ae3348e0.

The assumption that it is impossible to return an ERR pointer from
rpc_run_task() no longer holds due to commit 25cf32ad5dba ("SUNRPC:
Handle allocation failure in rpc_new_task()").

Fixes: 25cf32ad5dba ('SUNRPC: Handle allocation failure in rpc_new_task()')
Fixes: efe57fd58e1c ('SUNRPC: Remove unreachable error condition')
Signed-off-by: Dan Aloni <dan.aloni@vastdata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: RPC level errors should set task->tk_rpc_status

Fix up a case in call_encode() where we're failing to set
task->tk_rpc_status when an RPC level error occurred.

Fixes: 9c5948c24869 ("SUNRPC: task should be exit if encode return EKEYEXPIRED more times")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't reuse bvec on retransmission of the request

If a request is re-encoded and then retransmitted, we need to make sure
that we also re-encode the bvec, in case the page lists have changed.

Fixes: ff053dbbaffe ("SUNRPC: Move the call to xprt_send_pagedata() out of xprt_sock_sendmsg()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC create a function that probes only offline transports

For only offline transports, attempt to check connectivity via
a NULL call and, if that succeeds, call a provided session trunking
detection function.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC restructure rpc_clnt_setup_test_and_add_xprt

In preparation for code re-use, pull out the part of the
rpc_clnt_setup_test_and_add_xprt() portion that sends a NULL rpc
and then calls a session trunking function into a helper function.

Re-organize the end of the function for code re-use.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC create an rpc function that allows xprt removal from rpc_clnt

Expose a function that allows a removal of xprt from the rpc_clnt.

When called from NFS that's running a trunked transport then don't
decrement the active transport counter.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC enable back offline transports in trunking discovery

When we are adding a transport to a xprt_switch that's already on
the list but has been marked OFFLINE, then make the state ONLINE
since it's been tested now.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC create an iterator to list only OFFLINE xprts

Create a new iterator helper that will go thru the all the transports
in the switch and return transports that are marked OFFLINE.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC add function to offline remove trunkable transports

Iterate thru available transports in the xprt_switch for all
trunkable transports offline and possibly remote them as well.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fail faster on bad verifier

A bad verifier is not a garbage argument, it's an authentication
failure. Retrying it doesn't make the problem go away, and delays
upper layer recovery steps.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: set cl_max_connect when cloning an rpc_clnt

If the initial attempt at trunking detection using the krb5i auth flavor
fails with -EACCES, -NFS4ERR_CLID_INUSE, or -NFS4ERR_WRONGSEC, then the
NFS client tries again using auth_sys, cloning the rpc_clnt in the
process. If this second attempt at trunking detection succeeds, then
the resulting nfs_client->cl_rpcclient winds up having cl_max_connect=0
and subsequent attempts to add additional transport connections to the
rpc_clnt will fail with a message similar to the following being logged:

[502044.312640] SUNRPC: reached max allowed number (0) did not add
transport to server: 192.168.122.3

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fixes: dc48e0abee24 ("SUNRPC enforce creation of no more than max_connect xprts")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Ensure that the gssproxy client can start in a connected state

Ensure that the gssproxy client connects to the server from the gssproxy
daemon process context so that the AF_LOCAL socket connection is done
using the correct path and namespaces.

Fixes: 1d658336b05f ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Revert "SUNRPC: Ensure gss-proxy connects on setup"

This reverts commit 892de36fd4a98fab3298d417c051d9099af5448d.

The gssproxy server is unresponsive when it calls into the kernel to
start the upcall service, so it will not reply to our RPC ping at all.

Reported-by: "J.Bruce Fields" <bfields@fieldses.org>
Fixes: 892de36fd4a9 ("SUNRPC: Ensure gss-proxy connects on setup")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Ensure gss-proxy connects on setup

For reasons best known to the author, gss-proxy does not implement a
NULL procedure, and returns RPC_PROC_UNAVAIL. However we still want to
ensure that we connect to the service at setup time.
So add a quirk-flag specially for this case.

Fixes: 1d658336b05f ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC release the transport of a relocated task with an assigned transport

A relocated task must release its previous transport.

Fixes: 82ee41b85cef1 ("SUNRPC don't resend a task on an offlined transport")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Handle allocation failure in rpc_new_task()

If the call to rpc_alloc_task() fails, then ensure that the calldata is
released, and that rpc_run_task() and rpc_run_bc_task() bail out early.

Reported-by: NeilBrown <neilb@suse.de>
Fixes: 910ad38697d9 ("NFS: Fix memory allocation in rpc_alloc_task()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Handle low memory situations in call_status()

We need to handle ENFILE, ENOBUFS, and ENOMEM, because
xprt_wake_pending_tasks() can be called with any one of these due to
socket creation failures.

Fixes: b61d59fffd3e ("SUNRPC: xs_tcp_connect_worker{4,6}: merge common code")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Handle ENOMEM in call_transmit_status()

Both call_transmit() and call_bc_transmit() can now return ENOMEM, so
let's make sure that we handle the errors gracefully.

Fixes: 0472e4766049 ("SUNRPC: Convert socket page send code to use iov_iter()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: handle malloc failure in ->request_prepare

If ->request_prepare() detects an error, it sets ->rq_task->tk_status.
This is easy for callers to ignore.
The only caller is xprt_request_enqueue_receive() and it does ignore the
error, as does call_encode() which calls it. This can result in a
request being queued to receive a reply without an allocated receive buffer.

So instead of setting rq_task->tk_status, return an error, and store in
->tk_status only in call_encode();

The call to xprt_request_enqueue_receive() is now earlier in
call_encode(), where the error can still be handled.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC don't resend a task on an offlined transport

When a task is being retried, due to an NFS error, if the assigned
transport has been put offline and the task is relocatable pick a new
transport.

Fixes: 6f081693e7b2b ("sunrpc: remove an offlined xprt using sysfs")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: keep state manager thread active if swap is enabled

If we are swapping over NFSv4, we may not be able to allocate memory to
start the state-manager thread at the time when we need it.
So keep it always running when swap is enabled, and just signal it to
start.

This requires updating and testing the cl_swapper count on the root
rpc_clnt after following all ->cl_parent links.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC

rpc tasks can be marked as RPC_TASK_SWAPPER. This causes GFP_MEMALLOC
to be used for some allocations. This is needed in some cases, but not
in all where it is currently provided, and in some where it isn't
provided.

Currently *all* tasks associated with a rpc_client on which swap is
enabled get the flag and hence some GFP_MEMALLOC support.

GFP_MEMALLOC is provided for ->buf_alloc() but only swap-writes need it.
However xdr_alloc_bvec does not get GFP_MEMALLOC - though it often does
need it.

xdr_alloc_bvec is called while the XPRT_LOCK is held. If this blocks,
then it blocks all other queued tasks. So this allocation needs
GFP_MEMALLOC for *all* requests, not just writes, when the xprt is used
for any swap writes.

Similarly, if the transport is not connected, that will block all
requests including swap writes, so memory allocations should get
GFP_MEMALLOC if swap writes are possible.

So with this patch:
1/ we ONLY set RPC_TASK_SWAPPER for swap writes.
2/ __rpc_execute() sets PF_MEMALLOC while handling any task
with RPC_TASK_SWAPPER set, or when handling any task that
holds the XPRT_LOCKED lock on an xprt used for swap.
This removes the need for the RPC_IS_SWAPPER() test
in ->buf_alloc handlers.
3/ xprt_prepare_transmit() sets PF_MEMALLOC after locking
any task to a swapper xprt. __rpc_execute() will clear it.
3/ PF_MEMALLOC is set for all the connect workers.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com> (for xprtrdma parts)
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC/auth: async tasks mustn't block waiting for memory

When memory is short, new worker threads cannot be created and we depend
on the minimum one rpciod thread to be able to handle everything. So it
must not block waiting for memory.

mempools are particularly a problem as memory can only be released back
to the mempool by an async rpc task running. If all available workqueue
threads are waiting on the mempool, no thread is available to return
anything.

lookup_cred() can block on a mempool or kmalloc - and this can cause
deadlocks. So add a new RPCAUTH_LOOKUP flag for async lookups and don't
block on memory. If the -ENOMEM gets back to call_refreshresult(), wait
a short while and try again. HZ>>4 is chosen as it is used elsewhere
for -ENOMEM retries.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Convert GFP_NOFS to GFP_KERNEL

The sections which should not re-enter the filesystem are already
protected with memalloc_nofs_save/restore calls, so it is better to use
GFP_KERNEL in these calls to allow better performance for synchronous
RPC calls.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC allow for unspecified transport time in rpc_clnt_add_xprt

If the supplied argument doesn't specify the transport type, use the
type of the existing rpc clnt and its existing transport.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: remove unnecessary test in rpc_task_set_client()

In rpc_task_set_client(), testing for a NULL clnt is not necessary, as
clnt should always be a valid pointer to a rpc_client.

Signed-off-by: Thiago Rafael Becker <trbecker@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC enforce creation of no more than max_connect xprts

If we are adding new transports via rpc_clnt_test_and_add_xprt()
then check if we've reached the limit. Currently only pnfs path
adds transports via that function but this is done in
preparation when the client would add new transports when
session trunking is detected. A warning is logged if the
limit is reached.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC keep track of number of transports to unique addresses

Currently, xprt_switch keeps a number of all xprts (xps_nxprts)
that were added to the switch regardless of whethere it's an
nconnect transport or a transport to a trunkable address.
Introduce a new counter to keep track of transports to unique
destination addresses per xprt_switch.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Convert rpc_client refcount to use refcount_t

There are now tools in the refcount library that allow us to convert the
client shutdown code.

Reported-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Unset RPC_TASK_NO_RETRANS_TIMEOUT for NULL RPCs

In some rare failure modes, the server is actually reading the
transport, but then just dropping the requests on the floor.
TCP_USER_TIMEOUT cannot detect that case.

Prevent such a stuck server from pinning client resources
indefinitely by ensuring that certain idempotent requests
(such as NULL) can time out even if the connection is still
operational.

Otherwise rpc_bind_new_program(), gss_destroy_cred(), or
rpc_clnt_test_and_add_xprt() can wait forever.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Refactor rpc_ping()

Make it use the rpc_null_call_helper() so that it can share the
new rpc_call_ops structure to be introduced in the next patch.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: remove an offlined xprt using sysfs

Once a transport has been put offline, this transport can be also
removed from the list of transports. Any tasks that have been stuck
on this transport would find the next available active transport
and be re-tried. This transport would be removed from the xprt_switch
list and freed.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC mark the first transport

When an RPC client gets created it's first transport is special
and should be marked a main transport.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: add a symlink from rpc-client directory to the xprt_switch

An rpc client uses a transport switch and one ore more transports
associated with that switch. Since transports are shared among
rpc clients, create a symlink into the xprt_switch directory
instead of duplicating entries under each rpc client.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: Create per-rpc_clnt sysfs kobjects

These will eventually have files placed under them for sysfs operations.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC in case of backlog, hand free slots directly to waiting task

If sunrpc.tcp_max_slot_table_entries is small and there are tasks
on the backlog queue, then when a request completes it is freed and the
first task on the queue is woken. The expectation is that it will wake
and claim that request. However if it was a sync task and the waiting
process was killed at just that moment, it will wake and NOT claim the
request.

As long as TASK_CONGESTED remains set, requests can only be claimed by
tasks woken from the backlog, and they are woken only as requests are
freed, so when a task doesn't claim a request, no other task can ever
get that request until TASK_CONGESTED is cleared. Each time this
happens the number of available requests is decreased by one.

With a sufficiently high workload and sufficiently low setting of
max_slot (16 in the case where this was seen), TASK_CONGESTED can remain
set for an extended period, and the above scenario (of a process being
killed just as its task was woken) can repeat until no requests can be
allocated. Then traffic stops.

This patch addresses the problem by introducing a positive handover of a
request from a completing task to a backlog task - the request is never
freed when there is a backlog.

When a task is woken it might not already have a request attached in
which case it is *not* freed (as with current code) but is initialised
(if needed) and used. If it isn't used it will eventually be freed by
rpc_exit_task(). xprt_release() is enhanced to be able to correctly
release an uninitialised request.

Fixes: ba60eb25ff6b ("SUNRPC: Fix a livelock problem in the xprt->backlog queue")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: Fix misplaced barrier in call_decode

Fix a misplaced barrier in call_decode. The struct rpc_rqst is modified
as follows by xprt_complete_rqst:

req->rq_private_buf.len = copied;
/* Ensure all writes are done before we update */
/* req->rq_reply_bytes_recvd */
smp_wmb();
req->rq_reply_bytes_recvd = copied;

And currently read as follows by call_decode:

smp_rmb(); // misplaced
if (!req->rq_reply_bytes_recvd)
goto out;
req->rq_rcv_buf.len = req->rq_private_buf.len;

This patch places the smp_rmb after the if to ensure that
rq_reply_bytes_recvd and rq_private_buf.len are read in order.

Fixes: 9ba828861c56a ("SUNRPC: Don't try to parse incomplete RPC messages")
Signed-off-by: Baptiste Lepers <baptiste.lepers@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Move fault injection call sites

I've hit some crashes that occur in the xprt_rdma_inject_disconnect
path. It appears that, for some provides, rdma_disconnect() can
take so long that the transport can disconnect and release its
hardware resources while rdma_disconnect() is still running,
resulting in a UAF in the provider.

The transport's fault injection method may depend on the stability
of transport data structures. That means it needs to be invoked
only from contexts that hold the transport write lock.

Fixes: 4a0682583988 ("SUNRPC: Transport fault injection")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Clean up the handling of page padding in rpc_prepare_reply_pages()

rpc_prepare_reply_pages() currently expects the 'hdrsize' argument to
contain the length of the data that we expect to want placed in the head
kvec plus a count of 1 word of padding that is placed after the page data.
This is very confusing when trying to read the code, and sometimes leads
to callers adding an arbitrary value of '1' just in order to satisfy the
requirement (whether or not the page data actually needs such padding).

This patch aims to clarify the code by changing the 'hdrsize' argument
to remove that 1 word of padding. This means we need to subtract the
padding from all the existing callers.

Fixes: 02ef04e432ba ("NFS: Account for XDR pad of buf->pages")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Clean up call_bind_status() observability

Time to remove dprintk call sites in here.

Regarding the rpc_bind_status tracepoint: It's friendlier to
administrators if they don't have to look up the error code to
figure out what went wrong. Replace trace_rpc_bind_status with a
set of tracepoints that report more specifically what the problem
was, and what RPC program/version was being queried.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Remove dprintk call site in call_decode

Clean up.

When enabled, this dprintk adds a line in /var/log/messages after
every RPC that reports the task ID (no connection to on the wire
XID values) and the RPC's result (no connection to the program,
operation, or the arguments and results).

Thus it's value is pretty low. Let's remove it.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Trace call_refresh events

Clean up: Replace dprintk call sites.

Note that rpc_call_rpcerror() already has a trace point, so perhaps
adding trace_rpc_refresh_status() isn't necessary. However, it does
report a particular category of error.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add trace_rpc_timeout_status()

For a long while we've wanted a tracepoint that fires when a major
timeout is reported in the system log. Such a tracepoint can be
attached to other actions that can take place when a timeout is
detected (eg, server or connection health assessment).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Replace connect dprintk call sites with a tracepoint

This trace event can be used to audit transport connections from the
client.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Remove dprintk call site in call_start()

Clean up: The rpc_rpc_request tracepoint serves the same purpose.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Remove the dprint_status() macro

Clean up: The rpc_task_run_action tracepoint serves the same
purpose.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Hoist trace_xprtrdma_op_allocate into generic code

Introduce a tracepoint in call_allocate that reports the exact
sizes in the RPC buffer allocation request and the status of the
result. This helps catch problems with XDR buffer provisioning,
and replaces transport-specific debugging instrumentation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC dont update timeout value on connection reset

Current behaviour: every time a v3 operation is re-sent to the server
we update (double) the timeout. There is no distinction between whether
or not the previous timer had expired before the re-sent happened.

Here's the scenario:
1. Client sends a v3 operation
2. Server RST-s the connection (prior to the timeout) (eg., connection
is immediately reset)
3. Client re-sends a v3 operation but the timeout is now 120sec.

As a result, an application sees 2mins pause before a retry in case
server again does not reply. Where as if a connection reset didn't
change the timeout value, the client would have re-tried (the 3rd
time) after 60secs.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

SUNRPC: Set SOFTCONN when destroying GSS contexts

Move the RPC_TASK_SOFTCONN flag into rpc_call_null_helper(). The
only minor behavior change is that it is now also set when
destroying GSS contexts.

This gives a better guarantee that gss_send_destroy_context() will
not hang for long if a connection cannot be established.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: rpc_call_null_helper() should set RPC_TASK_SOFT

Clean up.

All of rpc_call_null_helper() call sites assert RPC_TASK_SOFT, so
move that setting into rpc_call_null_helper() itself.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: rpc_call_null_helper() already sets RPC_TASK_NULLCREDS

Clean up.

Commit a52458b48af1 ("NFS/NFSD/SUNRPC: replace generic creds with
'struct cred'.") made rpc_call_null_helper() set RPC_TASK_NULLCREDS
unconditionally. Therefore there's no need for
rpc_call_null_helper()'s call sites to set RPC_TASK_NULLCREDS.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: trace RPC client lifetime events

The "create" tracepoint records parts of the rpc_create arguments,
and the shutdown tracepoint records when the rpc_clnt is about to
signal pending tasks and destroy auths.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Split the xdr_buf event class

To help tie the recorded xdr_buf to a particular RPC transaction,
the client side version of this class should display task ID
information and the server side one should show the request's XID.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add tracepoint to rpc_call_rpcerror()

Add a tracepoint in another common exit point for failing RPCs.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: 'Directory with parent 'rpc_clnt' already present!'

Each rpc_client has a cl_clid which is allocated from a global ida, and
a debugfs directory which is named after cl_clid.

We're releasing the cl_clid before we free the debugfs directory named
after it. As soon as the cl_clid is released, that value is available
for another newly created client.

That leaves a window where another client may attempt to create a new
debugfs directory with the same name as the not-yet-deleted debugfs
directory from the dying client. Symptoms are log messages like

Directory 4 with parent 'rpc_clnt' already present!

Fixes: 7c4310ff5642 "SUNRPC: defer slow parts of rpc_free_client() to a workqueue."
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Signalled ASYNC tasks need to exit

Ensure that signalled ASYNC rpc_tasks exit immediately instead of
spinning until a timeout (or forever).

To avoid checking for the signal flag on every scheduler iteration,
the check is instead introduced in the client's finite state
machine.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Fixes: ae67bd3821bb ("SUNRPC: Fix up task signalling")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: fix use-after-free in rpc_free_client_work()

Parts of rpc_free_client() were recently moved to
a separate rpc_free_clent_work(). This introduced
a use-after-free as rpc_clnt_remove_pipedir() calls
rpc_net_ns(), and that uses clnt->cl_xprt which has already
been freed.
So move the call to xprt_put() after the call to
rpc_clnt_remove_pipedir().

Reported-by: syzbot+22b5ef302c7c40d94ea8@syzkaller.appspotmail.com
Fixes: 7c4310ff5642 ("SUNRPC: defer slow parts of rpc_free_client() to a workqueue.")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: defer slow parts of rpc_free_client() to a workqueue.

The rpciod workqueue is on the write-out path for freeing dirty memory,
so it is important that it never block waiting for memory to be
allocated - this can lead to a deadlock.

rpc_execute() - which is often called by an rpciod work item - calls
rcp_task_release_client() which can lead to rpc_free_client().

rpc_free_client() makes two calls which could potentially block wating
for memory allocation.

rpc_clnt_debugfs_unregister() calls into debugfs and will block while
any of the debugfs files are being accessed. In particular it can block
while any of the 'open' methods are being called and all of these use
malloc for one thing or another. So this can deadlock if the memory
allocation waits for NFS to complete some writes via rpciod.

rpc_clnt_remove_pipedir() can take the inode_lock() and while it isn't
obvious that memory allocations can happen while the lock it held, it is
safer to assume they might and to not let rpciod call
rpc_clnt_remove_pipedir().

So this patch moves these two calls (together with the final kfree() and
rpciod_down()) into a work-item to be run from the system work-queue.
rpciod can continue its important work, and the final stages of the free
can happen whenever they happen.

I have seen this deadlock on a 4.12 based kernel where debugfs used
synchronize_srcu() when removing objects. synchronize_srcu() requires a
workqueue and there were no free workther threads and none could be
allocated. While debugsfs no longer uses SRCU, I believe the deadlock
is still possible.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Remove unreachable error condition

rpc_clnt_test_and_add_xprt() invokes rpc_call_null_helper(), which
return the value of rpc_run_task() to "task". Since rpc_run_task() is
impossible to return an ERR pointer, there is no need to add the
IS_ERR() condition on "task" here. So we need to remove it.

Fixes: 7f554890587c ("SUNRPC: Allow addition of new transports to a struct rpc_clnt")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

svcrdma: Create a generic tracing class for displaying xdr_buf layout

This class can be used to create trace points in either the RPC
client or RPC server paths. It simply displays the length of each
part of an xdr_buf, which is useful to determine that the transport
and XDR codecs are operating correctly.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Don't take a reference to the cred on synchronous tasks

If the RPC call is synchronous, assume the cred is already pinned
by the caller.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Add a flag to avoid reference counts on credentials

Add a flag to signal to the RPC layer that the credential is already
pinned for the duration of the RPC call.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: call_connect_status should handle -EPROTO

The xprtrdma connect logic can return -EPROTO if the underlying
device or network path does not support RDMA. This can happen
after a device removal/insertion.

- When SOFTCONN is set, EPROTO is a permanent error.

- When SOFTCONN is not set, EPROTO is treated as a temporary error.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4.1: Don't rebind to the same source port when reconnecting to the server

NFSv2, v3 and NFSv4 servers often have duplicate replay caches that look
at the source port when deciding whether or not an RPC call is a replay
of a previous call. This requires clients to perform strange TCP gymnastics
in order to ensure that when they reconnect to the server, they bind
to the same source port.

NFSv4.1 and NFSv4.2 have sessions that provide proper replay semantics,
that do not look at the source port of the connection. This patch therefore
ensures they can ignore the rebind requirement.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Eliminate log noise in call_reserveresult

Sep 11 16:35:20 manet kernel:
call_reserveresult: unrecognized error -512, exiting

Diagnostic error messages such as this likely have no value for NFS
client administrators.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Don't try to parse incomplete RPC messages

If the copy of the RPC reply into our buffers did not complete, and
we could end up with a truncated message. In that case, just resend
the call.

Fixes: a0584ee9aed80 ("SUNRPC: Use struct xdr_stream when decoding...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: RPC level errors should always set task->tk_rpc_status

Ensure that we set task->tk_rpc_status for all RPC level errors so that
the caller can distinguish between those and server reply status errors.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Dequeue the request from the receive queue while we're re-encoding

Ensure that we dequeue the request from the transport receive queue
while we're re-encoding to prevent issues like use-after-free when
we release the bvec.

Fixes: 7536908982047 ("SUNRPC: Ensure the bvecs are reset when we re-encode...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Handle connection breakages correctly in call_status()

If the connection breaks while we're waiting for a reply from the
server, then we want to immediately try to reconnect.

Fixes: ec6017d90359 ("SUNRPC fix regression in umount of a secure mount")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Handle EADDRINUSE and ENOBUFS correctly

If a connect or bind attempt returns EADDRINUSE, that means we want to
retry with a different port. It is not a fatal connection error.
Similarly, ENOBUFS is not fatal, but just indicates a memory allocation
issue. Retry after a short delay.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't handle errors if the bind/connect succeeded

Don't handle errors in call_bind_status()/call_connect_status()
if it turns out that a previous call caused it to succeed.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v5.1+

SUNRPC: Ensure the bvecs are reset when we re-encode the RPC request

The bvec tracks the list of pages, so if the number of pages changes
due to a re-encode, we need to reset the bvec as well.

Fixes: 277e4ab7d530 ("SUNRPC: Simplify TCP receive code by switching...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20+

SUNRPC: Fix up backchannel slot table accounting

Add a per-transport maximum limit in the socket case, and add
helpers to allow the NFSv4 code to discover that limit.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix transport accounting when caller specifies an rpc_xprt

Ensure that we do the required accounting for the round robin queue
when the caller to rpc_init_task() has passed in a transport to be
used.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Reported-by: Neil Brown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: send state management on a single connection.

With NFSv4.1, different network connections need to be explicitly
bound to a session. During session startup, this is not possible
so only a single connection must be used for session startup.

So add a task flag to disable the default round-robin choice of
connections (when nconnect > 1) and force the use of a single
connection.
Then use that flag on all requests for session management - for
consistence, include NFSv4.0 management (SETCLIENTID) and session
destruction

Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Allow creation of RPC clients with multiple connections

Add an argument to struct rpc_create_args that allows the specification
of how many transport connections you want to set up to the server.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Add basic load balancing to the transport switch

For now, just count the queue length. It is less accurate than counting
number of bytes queued, but easier to implement.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix a credential refcount leak

All callers of __rpc_clone_client() pass in a value for args->cred,
meaning that the credential gets assigned and referenced in
the call to rpc_new_client().

Reported-by: Ido Schimmel <idosch@idosch.org>
Fixes: 79caa5fad47c ("SUNRPC: Cache cred of process creating the rpc_client")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net :sunrpc :clnt :Fix xps refcount imbalance on the error path

rpc_clnt_add_xprt take a reference to struct rpc_xprt_switch, but forget
to release it before return, may lead to a memory leak.

Signed-off-by: Lin Yi <teroincn@163.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix a use after free when a server rejects the RPCSEC_GSS credential

The addition of rpc_check_timeout() to call_decode causes an Oops
when the RPCSEC_GSS credential is rejected.
The reason is that rpc_decode_header() will call xprt_release() in
order to free task->tk_rqstp, which is needed by rpc_check_timeout()
to check whether or not we should exit due to a soft timeout.

The fix is to move the call to xprt_release() into call_decode() so
we can perform it after rpc_check_timeout().

Reported-by: Olga Kornievskaia <olga.kornievskaia@gmail.com>
Reported-by: Nick Bowler <nbowler@draconx.ca>
Fixes: cea57789e408 ("SUNRPC: Clean up")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC fix regression in umount of a secure mount

If call_status returns ENOTCONN, we need to re-establish the connection
state after. Otherwise the client goes into an infinite loop of call_encode,
call_transmit, call_status (ENOTCONN), call_encode.

Fixes: c8485e4d63 ("SUNRPC: Handle ECONNREFUSED correctly in xprt_transmit()")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Cc: stable@vger.kernel.org # v2.6.29+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

SUNRPC: task should be exit if encode return EKEYEXPIRED more times

If the rpc.gssd always return cred success, but now the cred is
expired, then the task will loop in call_refresh and call_transmit.

Exit the rpc task after retry.

Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Cache cred of process creating the rpc_client

When converting kuids to AUTH_UNIX creds, etc we will want to use the
same user namespace as the process that created the rpc client.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add the 'softerr' rpc_client flag

Add the 'softerr' rpc client flag that sets the RPC_TASK_TIMEOUT
flag on all new rpc tasks that are attached to that rpc client.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Ensure to ratelimit the "server not responding" syslog messages

In particular, the timeout messages can be very noisy, so we ought to
ratelimit them in order to avoid spamming the syslog.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Make "no retrans timeout" soft tasks behave like softconn for timeouts

If a soft NFSv4 request is sent, then we don't need it to time out unless
the connection breaks. The reason is that as long as the connection is
unbroken, the protocol states that the server is not allowed to drop the
request. IOW: as long as the connection remains unbroken, the client may
assume that all transmitted RPC requests are being processed by the server,
and that retransmissions and timeouts of those requests are unwarranted.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add tracking of RPC level errors

Add variables to track RPC level errors so that we can distinguish
between issue that arose in the RPC transport layer as opposed to
those arising from the reply message.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix up tracking of timeouts

Add a helper to ensure that debugfs and friends print out the
correct current task timeout value.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add function rpc_sleep_on_timeout()

Clean up the RPC task sleep interfaces by replacing the task->tk_timeout
'hidden parameter' to rpc_sleep_on() with a new function that takes an
absolute timeout.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Refactor rpc_restart_call/rpc_restart_call_prepare

Clean up.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix up task signalling

The RPC_TASK_KILLED flag should really not be set from another context
because it can clobber data in the struct task when task->tk_flags is
changed non-atomically.
Let's therefore swap out RPC_TASK_KILLED with an atomic flag, and add
a function to set that flag and safely wake up the task.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Ignore queue transmission errors on successful transmission

If a request transmission fails due to write space or slot unavailability
errors, but the queued task then gets transmitted before it has time to
process the error in call_transmit_status() or call_bc_transmit_status(),
we need to suppress the transmission error code to prevent it from leaking
out of the RPC layer.

Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>

Revert "SUNRPC: Micro-optimise when the task is known not to be sleeping"

This reverts commit 009a82f6437490c262584d65a14094a818bcb747.

The ability to optimise here relies on compiler being able to optimise
away tail calls to avoid stack overflows. Unfortunately, we are seeing
reports of problems, so let's just revert.

Reported-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't let RPC_SOFTCONN tasks time out if the transport is connected

If the transport is still connected, then we do want to allow
RPC_SOFTCONN tasks to retry. They should time out if and only if
the connection is broken.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Remove redundant check for the reply length in call_decode()

Now that we're using the xdr_stream functions to decode the header,
the test for the minimum reply length is redundant.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Handle the SYSTEM_ERR rpc error

Handle the SYSTEM_ERR rpc error by retrying the RPC call as if it
were a garbage argument.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: rpc_decode_header() must always return a non-zero value on error

Ensure that when the "garbage args" case falls through, we do set
an error of EIO.

Fixes: a0584ee9aed8 ("SUNRPC: Use struct xdr_stream when decoding...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix the minimal size for reply buffer allocation

We must at minimum allocate enough memory to be able to see any auth
errors in the reply from the server.

Fixes: 2c94b8eca1a26 ("SUNRPC: Use au_rslack when computing reply...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Take the transport send lock before binding+connecting

Before trying to bind a port, ensure we grab the send lock to
ensure that we don't change the port while another task is busy
transmitting requests.
The connect code already takes the send lock in xprt_connect(),
but it is harmless to take it before that.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Micro-optimise when the task is known not to be sleeping

In cases where we know the task is not sleeping, try to optimise
away the indirect call to task->tk_action() by replacing it with
a direct call.
Only change tail calls, to allow gcc to perform tail call
elimination.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Check whether the task was transmitted before rebind/reconnect

Before initiating transport actions that require putting the task to sleep,
such as rebinding or reconnecting, we should check whether or not the task
was already transmitted.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Remove redundant calls to RPC_IS_QUEUED()

The RPC task wakeup calls all check for RPC_IS_QUEUED() before taking any
locks. In addition, rpc_exit() already calls rpc_wake_up_queued_task().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Clean up

Replace remaining callers of call_timeout() with rpc_check_timeout().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Respect RPC call timeouts when retrying transmission

Fix a regression where soft and softconn requests are not timing out
as expected.

Fixes: 89f90fe1ad8b ("SUNRPC: Allow calls to xprt_transmit() to drain...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix up RPC back channel transmission

Now that transmissions happen through a queue, we require the RPC tasks
to handle error conditions that may have been set while they were
sleeping. The back channel does not currently do this, but assumes
that any error condition happens during its own call to xprt_transmit().

The solution is to ensure that the back channel splits out the
error handling just like the forward channel does.

Fixes: 89f90fe1ad8b ("SUNRPC: Allow calls to xprt_transmit() to drain...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Prevent thundering herd when the socket is not connected

If the socket is not connected, then we want to initiate a reconnect
rather that trying to transmit requests. If there is a large number
of requests queued and waiting for the lock in call_transmit(),
then it can take a while for one of the to loop back and retake
the lock in call_connect.

Fixes: 89f90fe1ad8b ("SUNRPC: Allow calls to xprt_transmit() to drain...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Use au_rslack when computing reply buffer size

au_rslack is significantly smaller than (au_cslack << 2). Using
that value results in smaller receive buffers. In some cases this
eliminates an extra segment in Reply chunks (RPC/RDMA).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add rpc_auth::au_ralign field

Currently rpc_inline_rcv_pages() uses au_rslack to estimate the
size of the upper layer reply header. This is fine for auth flavors
where au_verfsize == au_rslack.

However, some auth flavors have more going on. krb5i for example has
two more words after the verifier, and another blob following the
RPC message. The calculation involving au_rslack pushes the upper
layer reply header too far into the rcv_buf.

au_rslack is still valuable: it's the amount of buffer space needed
for the reply, and is used when allocating the reply buffer. We'll
keep that.

But, add a new field that can be used to properly estimate the
location of the upper layer header in each RPC reply, based on the
auth flavor in use.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS: Account for XDR pad of buf->pages

Certain NFS results (eg. READLINK) might expect a data payload that
is not an exact multiple of 4 bytes. In this case, XDR encoding
is required to pad that payload so its length on the wire is a
multiple of 4 bytes. The constants that define the maximum size of
each NFS result do not appear to account for this extra word.

In each case where the data payload is to be received into pages:

- 1 word is added to the size of the receive buffer allocated by
call_allocate

- rpc_inline_rcv_pages subtracts 1 word from @hdrsize so that the
extra buffer space falls into the rcv_buf's tail iovec

- If buf->pagelen is word-aligned, an XDR pad is not needed and
is thus removed from the tail

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Introduce rpc_prepare_reply_pages()

prepare_reply_buffer() and its NFSv4 equivalents expose the details
of the RPC header and the auth slack values to upper layer
consumers, creating a layering violation, and duplicating code.

Remedy these issues by adding a new RPC client API that hides those
details from upper layers in a common helper function.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Use struct xdr_stream when decoding RPC Reply header

Modernize and harden the code path that parses an RPC Reply
message.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Clean up rpc_verify_header()

- Recover some instruction count because I'm about to introduce a
few xdr_inline_decode call sites
- Replace dprintk() call sites with trace points
- Reduce the hot path so it fits in fewer cachelines

I've also renamed it rpc_decode_header() to match everything else
in the RPC client.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Use struct xdr_stream when constructing RPC Call header

Modernize and harden the code path that constructs each RPC Call
message.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Remove rpc_xprt::tsh_size

tsh_size was added to accommodate transports that send a pre-amble
before each RPC message. However, this assumes the pre-amble is
fixed in size, which isn't true for some transports. That makes
tsh_size not very generic.

Also I'd like to make the estimation of RPC send and receive
buffer sizes more precise. tsh_size doesn't currently appear to be
accounted for at all by call_allocate.

Therefore let's just remove the tsh_size concept, and make the only
transports that have a non-zero tsh_size employ a direct approach.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Ensure we respect the RPCSEC_GSS sequence number limit

According to RFC2203, the RPCSEC_GSS sequence numbers are bounded to
an upper limit of MAXSEQ = 0x80000000. Ensure that we handle that
correctly.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Ensure rq_bytes_sent is reset before request transmission

When we resend a request, ensure that the 'rq_bytes_sent' is reset
to zero.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Add xprt after nfs4_test_session_trunk()

Multipathing: In case of NFSv3, rpc_clnt_test_and_add_xprt() adds
the xprt to xprt switch (i.e. xps) if rpc_call_null_helper() returns
success. But in case of NFSv4.1, it needs to do EXCHANGEID to verify
the path along with check for session trunking.

Add the xprt in nfs4_test_session_trunk() only when
nfs4_detect_session_trunking() returns success. Also release refcount
hold by rpc_clnt_setup_test_and_add_xprt().

Signed-off-by: Santosh kumar pradhan <santoshkumar.pradhan@wdc.com>
Tested-by: Suresh Jayaraman <suresh.jayaraman@wdc.com>
Reported-by: Aditya Agnihotri <aditya.agnihotri@wdc.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.

SUNRPC has two sorts of credentials, both of which appear as
"struct rpc_cred".
There are "generic credentials" which are supplied by clients
such as NFS and passed in 'struct rpc_message' to indicate
which user should be used to authorize the request, and there
are low-level credentials such as AUTH_NULL, AUTH_UNIX, AUTH_GSS
which describe the credential to be sent over the wires.

This patch replaces all the generic credentials by 'struct cred'
pointers - the credential structure used throughout Linux.

For machine credentials, there is a special 'struct cred *' pointer
which is statically allocated and recognized where needed as
having a special meaning. A look-up of a low-level cred will
map this to a machine credential.

Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: add side channel to use non-generic cred for rpc call.

The credential passed in rpc_message.rpc_cred is always a
generic credential except in one instance.
When gss_destroying_context() calls rpc_call_null(), it passes
a specific credential that it needs to destroy.
In this case the RPC acts *on* the credential rather than
being authorized by it.

This special case deserves explicit support and providing that will
mean that rpc_message.rpc_cred is *always* generic, allowing
some optimizations.

So add "tk_op_cred" to rpc_task and "rpc_op_cred" to the setup data.
Use this to pass the cred down from rpc_call_null(), and have
rpcauth_bindcred() notice it and bind it in place.

Credit to kernel test robot <fengguang.wu@intel.com> for finding
a bug in earlier version of this patch.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: introduce RPC_TASK_NULLCREDS to request auth_none

In almost all cases the credential stored in rpc_message.rpc_cred
is a "generic" credential. One of the two expections is when an
AUTH_NULL credential is used such as for RPC ping requests.

To improve consistency, don't pass an explicit credential in
these cases, but instead pass NULL and set a task flag,
similar to RPC_TASK_ROOTCREDS, which requests that NULL credentials
be used by default.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS/SUNRPC: don't lookup machine credential until rpcauth_bindcred().

When NFS creates a machine credential, it is a "generic" credential,
not tied to any auth protocol, and is really just a container for
the princpal name.
This doesn't get linked to a genuine credential until rpcauth_bindcred()
is called.
The lookup always succeeds, so various places that test if the machine
credential is NULL, are pointless.

As a step towards getting rid of generic credentials, this patch gets
rid of generic machine credentials. The nfs_client and rpc_client
just hold a pointer to a constant principal name.
When a machine credential is wanted, a special static 'struct rpc_cred'
pointer is used. rpcauth_bindcred() recognizes this, finds the
principal from the client, and binds the correct credential.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix disconnection races

When the socket is closed, we need to call xprt_disconnect_done() in order
to clean up the XPRT_WRITE_SPACE flag, and wake up the sleeping tasks.

However, we also want to ensure that we don't wake them up before the socket
is closed, since that would cause thundering herd issues with everyone
piling up to retransmit before the TCP shutdown dance has completed.
Only the task that holds XPRT_LOCKED needs to wake up early in order to
allow the close to complete.

Reported-by: Dave Wysochanski <dwysocha@redhat.com>
Reported-by: Scott Mayhew <smayhew@redhat.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Fix a memory leak in call_encode()

If we retransmit an RPC request, we currently end up clobbering the
value of req->rq_rcv_buf.bvec that was allocated by the initial call to
xprt_request_prepare(req).

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: call_connect_status() must handle tasks that got transmitted

If a task failed to get the write lock in the call to xprt_connect(), then
it will be queued on xprt->sending. In that case, it is possible for it
to get transmitted before the call to call_connect_status(), in which
case it needs to be handled by call_transmit_status() instead.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Add a bvec array to struct xdr_buf for use with iovec_iter()

Add a bvec array to struct xdr_buf, and have the client allocate it
when we need to receive data into pages.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Clean up transport write space handling

Treat socket write space handling in the same way we now treat transport
congestion: by denying the XPRT_LOCK until the transport signals that it
has free buffer space.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Support for congestion control when queuing is enabled

Both RDMA and UDP transports require the request to get a "congestion control"
credit before they can be transmitted. Right now, this is done when
the request locks the socket. We'd like it to happen when a request attempts
to be transmitted for the first time.
In order to support retransmission of requests that already hold such
credits, we also want to ensure that they get queued first, so that we
don't deadlock with requests that have yet to obtain a credit.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Move RPC retransmission stat counter to xprt_transmit()

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't reset the request 'bytes_sent' counter when releasing XPRT_LOCK

If the request is still on the queue, this will be incorrect behaviour.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix up the back channel transmit

Fix up the back channel code to recognise that it has already been
transmitted, so does not need to be called again.
Also ensure that we set req->rq_task.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Refactor RPC call encoding

Move the call encoding so that it occurs before the transport connection
etc.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Add a transmission queue for RPC requests

Add the queue that will enforce the ordering of RPC task transmission.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Minor cleanup for call_transmit()

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Refactor xprt_transmit() to remove wait for reply code

Allow the caller in clnt.c to call into the code to wait for a reply
after calling xprt_transmit(). Again, the reason is that the backchannel
code does not need this functionality.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Refactor xprt_transmit() to remove the reply queue code

Separate out the action of adding a request to the reply queue so that the
backchannel code can simply skip calling it altogether.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Avoid holding locks across the XDR encoding of the RPC message

Currently, we grab the socket bit lock before we allow the message
to be XDR encoded. That significantly slows down the transmission
rate, since we serialise on a potentially blocking operation.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Simplify identification of when the message send/receive is complete

Add states to indicate that the message send and receive are not yet
complete.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: The transmitted message must lie in the RPCSEC window of validity

If a message has been encoded using RPCSEC_GSS, the server is
maintaining a window of sequence numbers that it considers valid.
The client should normally be tracking that window, and needs to
verify that the sequence number used by the message being transmitted
still lies inside the window of validity.

So far, we've been able to assume this condition would be realised
automatically, since the client has been encoding the message only
after taking the socket lock. Once we change that condition, we
will need the explicit check.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: If there is no reply expected, bail early from call_decode

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Clean up initialisation of the struct rpc_rqst

Move the initialisation back into xprt.c.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: whitespace fixes

Remove trailing whitespace and blank line at EOF

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4 client live hangs after live data migration recovery

After a live data migration event at the NFS server, the client may send
I/O requests to the wrong server, causing a live hang due to repeated
recovery events. On the wire, this will appear as an I/O request failing
with NFS4ERR_BADSESSION, followed by successful CREATE_SESSION, repeatedly.
NFS4ERR_BADSSESSION is returned because the session ID being used was
issued by the other server and is not valid at the old server.

The failure is caused by async worker threads having cached the transport
(xprt) in the rpc_task structure. After the migration recovery completes,
the task is redispatched and the task resends the request to the wrong
server based on the old value still present in tk_xprt.

The solution is to recompute the tk_xprt field of the rpc_task structure
so that the request goes to the correct server.

Signed-off-by: Bill Baker <bill.baker@oracle.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Helen Chao <helen.chao@oracle.com>
Fixes: fb43d17210ba ("SUNRPC: Use the multipath iterator to assign a ...")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Initialize rpc_rqst outside of xprt->reserve_lock

alloc_slot is a transport-specific op, but initializing an rpc_rqst
is common to all transports. In addition, the only part of initial-
izing an rpc_rqst that needs serialization is getting a fresh XID.

Move rpc_rqst initialization to common code in preparation for
adding a transport-specific alloc_slot to xprtrdma.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Add static trace point to report result of RPC ping

This information can help track down local misconfiguration issues
as well as network partitions and unresponsive servers.

There are several ways to send a ping, and with transport multi-
plexing, the exact rpc_xprt that is used is sometimes not known by
the upper layer. The rpc_xprt pointer passed to the trace point
call also has to be RCU-safe.

I found a spot inside the client FSM where an rpc_xprt pointer is
always available and safe to use.

Suggested-by: Bill Baker <Bill.Baker@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Simplify synopsis of some trace points

Clean up: struct rpc_task carries a pointer to a struct rpc_clnt,
and in fact task->tk_client is always what is passed into trace
points that are already passing @task.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net: make getname() functions return length rather than use int* parameter

Changes since v1:
Added changes in these files:
drivers/infiniband/hw/usnic/usnic_transport.c
drivers/staging/lustre/lnet/lnet/lib-socket.c
drivers/target/iscsi/iscsi_target_login.c
drivers/vhost/net.c
fs/dlm/lowcomms.c
fs/ocfs2/cluster/tcp.c
security/tomoyo/network.c

Before:
All these functions either return a negative error indicator,
or store length of sockaddr into "int *socklen" parameter
and return zero on success.

"int *socklen" parameter is awkward. For example, if caller does not
care, it still needs to provide on-stack storage for the value
it does not need.

None of the many FOO_getname() functions of various protocols
ever used old value of *socklen. They always just overwrite it.

This change drops this parameter, and makes all these functions, on success,
return length of sockaddr. It's always >= 0 and can be differentiated
from an error.

Tests in callers are changed from "if (err)" to "if (err < 0)", where needed.

rpc_sockname() lost "int buflen" parameter, since its only use was
to be passed to kernel_getsockname() as &buflen and subsequently
not used in any way.

Userspace API is not changed.

text data bss dec hex filename
30108430 2633624 873672 33615726 200ef6e vmlinux.before.o
30108109 2633612 873672 33615393 200ee21 vmlinux.o

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: David S. Miller <davem@davemloft.net>
CC: linux-kernel@vger.kernel.org
CC: netdev@vger.kernel.org
CC: linux-bluetooth@vger.kernel.org
CC: linux-decnet-user@lists.sourceforge.net
CC: linux-wireless@vger.kernel.org
CC: linux-rdma@vger.kernel.org
CC: linux-sctp@vger.kernel.org
CC: linux-nfs@vger.kernel.org
CC: linux-x25@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

SUNRPC: Remove rpc_protocol()

Since nfs4_create_referral_server was the only call site of
rpc_protocol, rpc_protocol can now be removed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Handle ENETDOWN errors

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Add rpc_request static trace point

Display information about the RPC procedure being requested in the
trace log. This sometimes critical information cannot always be
derived from other RPC trace entries.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net: sunrpc: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: remove some dead code.

RPC_TASK_NO_RETRANS_TIMEOUT is set when cl_noretranstimeo
is set, which happens when RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT is set,
which happens when NFS_CS_NO_RETRANS_TIMEOUT is set.

This flag means "don't resend on a timeout, only resend if the
connection gets broken for some reason".

cl_discrtry is set when RPC_CLNT_CREATE_DISCRTRY is set, which
happens when NFS_CS_DISCRTRY is set.

This flag means "always disconnect before resending".

NFS_CS_NO_RETRANS_TIMEOUT and NFS_CS_DISCRTRY are both only set
in nfs4_init_client(), and it always sets both.

So we will never have a situation where only one of the flags is set.
So this code, which tests if timeout retransmits are allowed, and
disconnection is required, will never run.

So it makes sense to remove this code as it cannot be tested and
could confuse people reading the code (like me).

(alternately we could leave it there with a comment saying
it is never actually used).

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: ECONNREFUSED should cause a rebind.

If you
- mount and NFSv3 filesystem
- do some file locking which requires the server
to make a GRANT call back
- unmount
- mount again and do the same locking

then the second attempt at locking suffers a 30 second delay.
Unmounting and remounting causes lockd to stop and restart,
which causes it to bind to a new port.
The server still thinks the old port is valid and gets ECONNREFUSED
when trying to contact it.
ECONNREFUSED should be seen as a hard error that is not worth
retrying. Rebinding is the only reasonable response.

This patch forces a rebind if that makes sense.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: mark all struct rpc_procinfo instances as const

struct rpc_procinfo contains function pointers, and marking it as
constant avoids it being able to be used as an attach vector for
code injections.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: move p_count out of struct rpc_procinfo

p_count is the only writeable memeber of struct rpc_procinfo, which is
a good candidate to be const-ified as it contains function pointers.

This patch moves it into out out struct rpc_procinfo, and into a
separate writable array that is pointed to by struct rpc_version and
indexed by p_statidx.

Signed-off-by: Christoph Hellwig <hch@lst.de>

sunrpc: properly type argument to kxdrdproc_t

Pass struct rpc_request as the first argument instead of an untyped blob.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: properly type argument to kxdreproc_t

Pass struct rpc_request as the first argument instead of an untyped blob,
and mark the data object as const.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

sunrpc: mark all struct rpc_procinfo instances as const

struct rpc_procinfo contains function pointers, and marking it as
constant avoids it being able to be used as an attach vector for
code injections.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: move p_count out of struct rpc_procinfo

p_count is the only writeable memeber of struct rpc_procinfo, which is
a good candidate to be const-ified as it contains function pointers.

This patch moves it into out out struct rpc_procinfo, and into a
separate writable array that is pointed to by struct rpc_version and
indexed by p_statidx.

Signed-off-by: Christoph Hellwig <hch@lst.de>

sunrpc: properly type argument to kxdrdproc_t

Pass struct rpc_request as the first argument instead of an untyped blob.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: properly type argument to kxdreproc_t

Pass struct rpc_request as the first argument instead of an untyped blob,
and mark the data object as const.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

sunrpc: don't check for failure from mempool_alloc()

When mempool_alloc() is allowed to sleep (GFP_NOIO allows
sleeping) it cannot fail.
So rpc_alloc_task() cannot fail, so rpc_new_task doesn't need
to test for failure.
Consequently rpc_new_task() cannot fail, so the callers
don't need to test.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4: Set the connection timeout to match the lease period

Set the timeout for TCP connections to be 1 lease period to ensure
that we don't lose our lease due to a faulty TCP connection.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Allow changing of the TCP timeout parameters on the fly

When the NFSv4 server tells us the lease period, we usually want
to adjust down the timeout parameters on the TCP connection to
ensure that we don't miss lease renewals due to a faulty connection.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Remove unused function rpc_get_timeout()

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: cleanup ida information when removing sunrpc module

After removing sunrpc module, I get many kmemleak information as,
unreferenced object 0xffff88003316b1e0 (size 544):
comm "gssproxy", pid 2148, jiffies 4294794465 (age 4200.081s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffffb0cfb58a>] kmemleak_alloc+0x4a/0xa0
[<ffffffffb03507fe>] kmem_cache_alloc+0x15e/0x1f0
[<ffffffffb0639baa>] ida_pre_get+0xaa/0x150
[<ffffffffb0639cfd>] ida_simple_get+0xad/0x180
[<ffffffffc06054fb>] nlmsvc_lookup_host+0x4ab/0x7f0 [lockd]
[<ffffffffc0605e1d>] lockd+0x4d/0x270 [lockd]
[<ffffffffc06061e5>] param_set_timeout+0x55/0x100 [lockd]
[<ffffffffc06cba24>] svc_defer+0x114/0x3f0 [sunrpc]
[<ffffffffc06cbbe7>] svc_defer+0x2d7/0x3f0 [sunrpc]
[<ffffffffc06c71da>] rpc_show_info+0x8a/0x110 [sunrpc]
[<ffffffffb044a33f>] proc_reg_write+0x7f/0xc0
[<ffffffffb038e41f>] __vfs_write+0xdf/0x3c0
[<ffffffffb0390f1f>] vfs_write+0xef/0x240
[<ffffffffb0392fbd>] SyS_write+0xad/0x130
[<ffffffffb0d06c37>] entry_SYSCALL_64_fastpath+0x1a/0xa9
[<ffffffffffffffff>] 0xffffffffffffffff

I found, the ida information (dynamic memory) isn't cleanup.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Fixes: 2f048db4680a ("SUNRPC: Add an identifier for struct rpc_clnt")
Cc: stable@vger.kernel.org # v3.12+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: Don't engage exponential backoff when connection attempt is rejected.

xs_connect() contains an exponential backoff mechanism so the repeated
connection attempts are delayed by longer and longer amounts.

This is appropriate when the connection failed due to a timeout, but
it not appropriate when a definitive "no" answer is received. In such
cases, call_connect_status() imposes a minimum 3-second back-off, so
not having the exponetial back-off will never result in immediate
retries.

The current situation is a problem when the NFS server tries to
register with rpcbind but rpcbind isn't running. All connection
attempts are made on the same "xprt" and as the connection is never
"closed", the exponential back delays successive attempts to register,
or de-register, different protocols. This results in a multi-minute
delay with no benefit.

So, when call_connect_status() receives a definitive "no", use
xprt_conditional_disconnect() to cancel the previous connection attempt.
This will set XPRT_CLOSE_WAIT so that xprt->ops->close() calls xs_close()
which resets the reestablish_timeout.

To ensure xprt_conditional_disconnect() does the right thing, we
ensure that rq_connect_cookie is set before a connection attempt, and
allow xprt_conditional_disconnect() to complete even when the
transport is not fully connected.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix suspicious RCU usage

We need to hold the rcu_read_lock() when calling rcu_dereference(),
otherwise we can't guarantee that the object being dereferenced still
exists.

Fixes: 39e5d2df ("SUNRPC search xprt switch for sockaddr")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Separate buffer pointers for RPC Call and Reply messages

For xprtrdma, the RPC Call and Reply buffers are involved in real
I/O operations.

To start with, the DMA direction of the I/O for a Call is opposite
that of a Reply.

In the current arrangement, the Reply buffer address is on a
four-byte alignment just past the call buffer. Would be friendlier
on some platforms if that was at a DMA cache alignment instead.

Because the current arrangement allocates a single memory region
which contains both buffers, the RPC Reply buffer often contains a
page boundary in it when the Call buffer is large enough (which is
frequent).

It would be a little nicer for setting up DMA operations (and
possible registration of the Reply buffer) if the two buffers were
separated, well-aligned, and contained as few page boundaries as
possible.

Now, I could just pad out the single memory region used for the pair
of buffers. But frequently that would mean a lot of unused space to
ensure the Reply buffer did not have a page boundary.

Add a separate pointer to rpc_rqst that points right to the RPC
Reply buffer. This makes no difference to xprtsock, but it will help
xprtrdma in subsequent patches.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Generalize the RPC buffer allocation API

xprtrdma needs to allocate the Call and Reply buffers separately.
TBH, the reliance on using a single buffer for the pair of XDR
buffers is transport implementation-specific.

Transports that want to allocate separate Call and Reply buffers
will ignore the "size" argument anyway. Don't bother passing it.

The buf_alloc method can't return two pointers. Instead, make the
method's return value an error code, and set the rq_buffer pointer
in the method itself.

This gives call_allocate an opportunity to terminate an RPC instead
of looping forever when a permanent problem occurs. If a request is
just bogus, or the transport is in a state where it can't allocate
resources for any request, there needs to be a way to kill the RPC
right there and not loop.

This immediately fixes a rare problem in the backchannel send path,
which loops if the server happens to send a CB request whose
call+reply size is larger than a page (which it shouldn't do yet).

One more issue: looks like xprt_inject_disconnect was incorrectly
placed in the failure path in call_allocate. It needs to be in the
success path, as it is for other call-sites.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Refactor rpc_xdr_buf_init()

Clean up: there is some XDR initialization logic that is common
to the forward channel and backchannel. Move it to an XDR header
so it can be shared.

rpc_rqst::rq_buffer points to a buffer containing big-endian data.
Update its annotation as part of the clean up.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: rpc_clnt_add_xprt setup function for NFS layer

Use a setup function to call into the NFS layer to test an rpc_xprt
for session trunking so as to not leak the rpc_xprt_switch into
the nfs layer.

Search for the address in the rpc_xprt_switch first so as not to
put an unnecessary EXCHANGE_ID on the wire.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC search xprt switch for sockaddr

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC rpc_clnt_xprt_switch_add_xprt

Give the NFS layer access to the rpc_xprt_switch_add_xprt function

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC rpc_clnt_xprt_switch_put

Give the NFS layer access to the xprt_switch_put function

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC remove rpc_task_release_client from rpc_task_set_client

rpc_task_set_client is only called from rpc_run_task after
rpc_new_task and rpc_task_release_client is not needed as the
task is new.

When called from rpc_new_task, rpc_task_set_client also removed the
assigned rpc_xprt which is not desired.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Remove unnecessary variable

The variable `err` is not used anywhere and just returns the
predefined value `0` at the end of the function. Hence, remove the
variable and return 0 explicitly.

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Silence WARN_ON when NFSv4.1 over RDMA is in use

Using NFSv4.1 on RDMA should be safe, so broaden the new checks in
rpc_create().

WARN_ON_ONCE is used, matching most other WARN call sites in clnt.c.

Fixes: 39a9beab5acb ("rpc: share one xps between all backchannels")
Fixes: d50039ea5ee6 ("nfsd4/rpc: move backchannel create logic...")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4: Cap the transport reconnection timer at 1/2 lease period

We don't want to miss a lease period renewal due to the TCP connection
failing to reconnect in a timely fashion. To ensure this doesn't happen,
cap the reconnection timer so that we retry the connection attempt
at least every 1/2 lease period.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Limit the reconnect backoff timer to the max RPC message timeout

...and ensure that we propagate it to new transports on the same
client.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix a compiler warning in fs/nfs/clnt.c

Fix the report:

net/sunrpc/clnt.c:2580:1: warning: ‘static’ is not at beginning of declaration [-Wold-style-declaration]

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

rpc: share one xps between all backchannels

The spec allows backchannels for multiple clients to share the same tcp
connection. When that happens, we need to use the same xprt for all of
them. Similarly, we need the same xps.

This fixes list corruption introduced by the multipath code.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>

nfsd4/rpc: move backchannel create logic into rpc code

Also simplify the logic a bit.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>

SUNRPC: fix xprt leak on xps allocation failure

Callers of rpc_create_xprt expect it to put the xprt on success and
failure.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>

sunrpc: Advertise maximum backchannel payload size

RPC-over-RDMA transports have a limit on how large a backward
direction (backchannel) RPC message can be. Ensure that the NFSv4.x
CREATE_SESSION operation advertises this limit to servers.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Allow addition of new transports to a struct rpc_clnt

Add a function to allow creation and addition of a new transport
to an existing rpc_clnt

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Make NFS swap work with multipath

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Add a helper to apply a function to all the rpc_clnt's transports

Add a helper for tasks that require us to apply a function to all the
transports in an rpc_clnt.
An example of a usecase would be BIND_CONN_TO_SESSION, where we want
to send one RPC call down each transport.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Use the multipath iterator to assign a transport to each task

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Make rpc_clnt store the multipath iterators

This is a pre-patch for the RPC multipath code. It sets up the storage in
struct rpc_clnt for the multipath code.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Remove unused function rpc_task_reset_client

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix a missing break in rpc_anyaddr()

The missing break means that we always return EAFNOSUPPORT when
faced with a request for an IPv6 loopback address.

Reported-by: coverity (CID 401987)
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Don't reencode message if transmission failed with ENOBUFS

If we're running out of buffer memory when transmitting data, then
we want to just delay for a moment, and then continue transmitting
the remainder of the message.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Handle connection issues correctly on the back channel

If the back channel is disconnected, we can and should just fail the
transmission. The expectation is that the NFSv4.1 server will always
retransmit any outstanding callbacks once the connection is
re-established.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Transport fault injection

It has been exceptionally useful to exercise the logic that handles
local immediate errors and RDMA connection loss. To enable
developers to test this regularly and repeatably, add logic to
simulate connection loss every so often.

Fault injection is disabled by default. It is enabled with

$ sudo echo xxx > /sys/kernel/debug/sunrpc/inject_fault/disconnect

where "xxx" is a large positive number of transport method calls
before a disconnect. A value of several thousand is usually a good
number that allows reasonable forward progress while still causing a
lot of connection drops.

These hooks are disabled when SUNRPC_DEBUG is turned off.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: turn swapper_enable/disable functions into rpc_xprt_ops

RDMA xprts don't have a sock_xprt, but an rdma_xprt, so the
xs_swapper_enable/disable functions will likely oops when fed an RDMA
xprt. Turn these functions into rpc_xprt_ops so that that doesn't
occur. For now the RDMA versions are no-ops that just return -EINVAL
on an attempt to swapon.

Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: make xprt->swapper an atomic_t

Split xs_swapper into enable/disable functions and eliminate the
"enable" flag.

Currently, it's racy if you have multiple swapon/swapoff operations
running in parallel over the same xprt. Also fix it so that we only
set it to a memalloc socket on a 0->1 transition and only clear it
on a 1->0 transition.

Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: keep a count of swapfiles associated with the rpc_clnt

Jerome reported seeing a warning pop when working with a swapfile on
NFS. The nfs_swap_activate can end up calling sk_set_memalloc while
holding the rcu_read_lock and that function can sleep.

To fix that, we need to take a reference to the xprt while holding the
rcu_read_lock, set the socket up for swapping and then drop that
reference. But, xprt_put is not exported and having NFS deal with the
underlying xprt is a bit of layering violation anyway.

Fix this by adding a set of activate/deactivate functions that take a
rpc_clnt pointer instead of an rpc_xprt, and have nfs_swap_activate and
nfs_swap_deactivate call those.

Also, add a per-rpc_clnt atomic counter to keep track of the number of
active swapfiles associated with it. When the counter does a 0->1
transition, we enable swapping on the xprt, when we do a 1->0 transition
we disable swapping on it.

This also allows us to be a bit more selective with the RPC_TASK_SWAPPER
flag. If non-swapper and swapper clnts are sharing a xprt, then we only
need to flag the tasks from the swapper clnt with that flag.

Acked-by: Mel Gorman <mgorman@suse.de>
Reported-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Remove unused argument 'tk_ops' in rpc_run_bc_task

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Backchannel handle socket nospace

If the socket was busy due to a socket nospace error, then we should
retry the send.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: make debugfs file creation failure non-fatal

v2: gracefully handle the case where some dentry pointers end up NULL
and be more dilligent about zeroing out dentry pointers

We currently have a problem that SELinux policy is being enforced when
creating debugfs files. If a debugfs file is created as a side effect of
doing some syscall, then that creation can fail if the SELinux policy
for that process prevents it.

This seems wrong. We don't do that for files under /proc, for instance,
so Bruce has proposed a patch to fix that.

While discussing that patch however, Greg K.H. stated:

"No kernel code should care / fail if a debugfs function fails, so
please fix up the sunrpc code first."

This patch converts all of the sunrpc debugfs setup code to be void
return functins, and the callers to not look for errors from those
functions.

This should allow rpc_clnt and rpc_xprt creation to work, even if the
kernel fails to create debugfs files for some reason.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: make debugfs file creation failure non-fatal

We currently have a problem that SELinux policy is being enforced when
creating debugfs files. If a debugfs file is created as a side effect of
doing some syscall, then that creation can fail if the SELinux policy
for that process prevents it.

This seems wrong. We don't do that for files under /proc, for instance,
so Bruce has proposed a patch to fix that.

While discussing that patch however, Greg K.H. stated:

"No kernel code should care / fail if a debugfs function fails, so
please fix up the sunrpc code first."

This patch converts all of the sunrpc debugfs setup code to be void
return functins, and the callers to not look for errors from those
functions.

This should allow rpc_clnt and rpc_xprt creation to work, even if the
kernel fails to create debugfs files for some reason.

Symptoms were failing krb5 mounts on systems using gss-proxy and
selinux.

Fixes: 388f0c776781 "sunrpc: add a debugfs rpc_xprt directory..."
Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: Handle EADDRINUSE on connect

Now that we're setting SO_REUSEPORT, we still need to handle the
case where a connect() is attempted, but the old socket is still
lingering.
Essentially, all we want to do here is handle the error by waiting
a few seconds and then retrying.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: NULL utsname dereference on NFS umount during namespace cleanup

Fix an Oopsable condition when nsm_mon_unmon is called as part of the
namespace cleanup, which now apparently happens after the utsname
has been freed.

Link: http://lkml.kernel.org/r/20150125220604.090121ae@neptune.home
Reported-by: Bruno Prémont <bonbons@linux-vserver.org>
Cc: stable@vger.kernel.org # 3.18
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: add debugfs file for displaying client rpc_task queue

It's possible to get a dump of the RPC task queue by writing a value to
/proc/sys/sunrpc/rpc_debug. If you write any value to that file, you get
a dump of the RPC client task list into the log buffer. This is a rather
inconvenient interface however, and makes it hard to get immediate info
about the task queue.

Add a new directory hierarchy under debugfs:

sunrpc/
rpc_clnt/
<clientid>/

Within each clientid directory we create a new "tasks" file that will
dump info similar to what shows up in the log buffer, but with a few
small differences -- we avoid printing raw kernel addresses in favor of
symbolic names and the XID is also displayed.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

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>

SUNRPC: Add missing support for RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT

The flag RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT was intended introduced in
order to allow NFSv4 clients to disable resend timeouts. Since those
cause the RPC layer to break the connection, they mess up the duplicate
reply caches that remain indexed on the port number in NFSv4..

This patch includes the code that was missing in the original to
set the appropriate flag in struct rpc_clnt, when the caller of
rpc_create() sets RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT.

Fixes: 8a19a0b6cb2e (SUNRPC: Add RPC task and client level options to...)
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

rpc: Add -EPERM processing for xs_udp_send_request()

If an iptables drop rule is added for an nfs server, the client can end up in
a softlockup. Because of the way that xs_sendpages() is structured, the -EPERM
is ignored since the prior bits of the packet may have been successfully queued
and thus xs_sendpages() returns a non-zero value. Then, xs_udp_send_request()
thinks that because some bits were queued it should return -EAGAIN. We then try
the request again and again, resulting in cpu spinning. Reproducer:

1) open a file on the nfs server '/nfs/foo' (mounted using udp)
2) iptables -A OUTPUT -d <nfs server ip> -j DROP
3) write to /nfs/foo
4) close /nfs/foo
5) iptables -D OUTPUT -d <nfs server ip> -j DROP

The softlockup occurs in step 4 above.

The previous patch, allows xs_sendpages() to return both a sent count and
any error values that may have occurred. Thus, if we get an -EPERM, return
that to the higher level code.

With this patch in place we can successfully abort the above sequence and
avoid the softlockup.

I also tried the above test case on an nfs mount on tcp and although the system
does not softlockup, I still ended up with the 'hung_task' firing after 120
seconds, due to the i/o being stuck. The tcp case appears a bit harder to fix,
since -EPERM appears to get ignored much lower down in the stack and does not
propogate up to xs_sendpages(). This case is not quite as insidious as the
softlockup and it is not addressed here.

Reported-by: Yigong Lou <ylou@akamai.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Handle EPIPE in xprt_connect_status

The callback handler xs_error_report() can end up propagating an EPIPE
error by means of the call to xprt_wake_pending_tasks(). Ensure that
xprt_connect_status() does not automatically convert this into an
EIO error.

Reported-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure that we handle ENOBUFS errors correctly.

Currently, an ENOBUFS error will result in a fatal error for the RPC
call. Normally, we will just want to wait and then retry.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: New helper for creating client with rpc_xprt

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: rpc_restart_call/rpc_restart_call_prepare should clear task->tk_status

When restarting an rpc call, we should not be carrying over data from the
previous call.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure call_connect_status() deals correctly with SOFTCONN tasks

Don't schedule an rpc_delay before checking to see if the task
is a SOFTCONN because the tk_callback from the delay (__rpc_atrun)
clears the task status before the rpc_exit_task can be run.

Signed-off-by: Steve Dickson <steved@redhat.com>
Fixes: 561ec1603171c (SUNRPC: call_connect_status should recheck...)
Link: http://lkml.kernel.org/r/5329CF7C.7090308@RedHat.com
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure call_status() deals correctly with SOFTCONN tasks

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure that call_bind times out correctly

If the rpcbind server is unavailable, we still want the RPC client
to respect the timeout.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure that call_connect times out correctly

When the server is unavailable due to a networking error, etc, we want
the RPC client to respect the timeout delays when attempting to reconnect.

Reported-by: Neil Brown <neilb@suse.de>
Fixes: 561ec1603171 (SUNRPC: call_connect_status should recheck bind..)
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: Fix infinite loop in RPC state machine

When a task enters call_refreshresult with status 0 from call_refresh and
!rpcauth_uptodatecred(task) it enters call_refresh again with no rate-limiting
or max number of retries.

Instead of trying forever, make use of the retry path that other errors use.

This only seems to be possible when the crrefresh callback is gss_refresh_null,
which only happens when destroying the context.

To reproduce:

1) mount with sec=krb5 (or sec=sys with krb5 negotiated for non FSID specific
operations).

2) reboot - the client will be stuck and will need to be hard rebooted

BUG: soft lockup - CPU#0 stuck for 22s! [kworker/0:2:46]
Modules linked in: rpcsec_gss_krb5 nfsv4 nfs fscache ppdev crc32c_intel aesni_intel aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd serio_raw i2c_piix4 i2c_core e1000 parport_pc parport shpchp nfsd auth_rpcgss oid_registry exportfs nfs_acl lockd sunrpc autofs4 mptspi scsi_transport_spi mptscsih mptbase ata_generic floppy
irq event stamp: 195724
hardirqs last enabled at (195723): [<ffffffff814a925c>] restore_args+0x0/0x30
hardirqs last disabled at (195724): [<ffffffff814b0a6a>] apic_timer_interrupt+0x6a/0x80
softirqs last enabled at (195722): [<ffffffff8103f583>] __do_softirq+0x1df/0x276
softirqs last disabled at (195717): [<ffffffff8103f852>] irq_exit+0x53/0x9a
CPU: 0 PID: 46 Comm: kworker/0:2 Not tainted 3.13.0-rc3-branch-dros_testing+ #4
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
Workqueue: rpciod rpc_async_schedule [sunrpc]
task: ffff8800799c4260 ti: ffff880079002000 task.ti: ffff880079002000
RIP: 0010:[<ffffffffa0064fd4>] [<ffffffffa0064fd4>] __rpc_execute+0x8a/0x362 [sunrpc]
RSP: 0018:ffff880079003d18 EFLAGS: 00000246
RAX: 0000000000000005 RBX: 0000000000000007 RCX: 0000000000000007
RDX: 0000000000000007 RSI: ffff88007aecbae8 RDI: ffff8800783d8900
RBP: ffff880079003d78 R08: ffff88006e30e9f8 R09: ffffffffa005a3d7
R10: ffff88006e30e7b0 R11: ffff8800783d8900 R12: ffffffffa006675e
R13: ffff880079003ce8 R14: ffff88006e30e7b0 R15: ffff8800783d8900
FS: 0000000000000000(0000) GS:ffff88007f200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3072333000 CR3: 0000000001a0b000 CR4: 00000000001407f0
Stack:
ffff880079003d98 0000000000000246 0000000000000000 ffff88007a9a4830
ffff880000000000 ffffffff81073f47 ffff88007f212b00 ffff8800799c4260
ffff8800783d8988 ffff88007f212b00 ffffe8ffff604800 0000000000000000
Call Trace:
[<ffffffff81073f47>] ? trace_hardirqs_on_caller+0x145/0x1a1
[<ffffffffa00652d3>] rpc_async_schedule+0x27/0x32 [sunrpc]
[<ffffffff81052974>] process_one_work+0x211/0x3a5
[<ffffffff810528d5>] ? process_one_work+0x172/0x3a5
[<ffffffff81052eeb>] worker_thread+0x134/0x202
[<ffffffff81052db7>] ? rescuer_thread+0x280/0x280
[<ffffffff81052db7>] ? rescuer_thread+0x280/0x280
[<ffffffff810584a0>] kthread+0xc9/0xd1
[<ffffffff810583d7>] ? __kthread_parkme+0x61/0x61
[<ffffffff814afd6c>] ret_from_fork+0x7c/0xb0
[<ffffffff810583d7>] ? __kthread_parkme+0x61/0x61
Code: e8 87 63 fd e0 c6 05 10 dd 01 00 01 48 8b 43 70 4c 8d 6b 70 45 31 e4 a8 02 0f 85 d5 02 00 00 4c 8b 7b 48 48 c7 43 48 00 00 00 00 <4c> 8b 4b 50 4d 85 ff 75 0c 4d 85 c9 4d 89 cf 0f 84 32 01 00 00

And the output of "rpcdebug -m rpc -s all":

RPC: 61 call_refresh (status 0)
RPC: 61 call_refresh (status 0)
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0
RPC: 61 call_refreshresult (status 0)
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0
RPC: 61 call_refreshresult (status 0)
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0
RPC: 61 call_refresh (status 0)
RPC: 61 call_refreshresult (status 0)
RPC: 61 call_refresh (status 0)
RPC: 61 call_refresh (status 0)
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0
RPC: 61 call_refreshresult (status 0)
RPC: 61 call_refresh (status 0)
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0
RPC: 61 call_refresh (status 0)
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0
RPC: 61 call_refreshresult (status 0)
RPC: 61 call_refresh (status 0)
RPC: 61 call_refresh (status 0)
RPC: 61 call_refresh (status 0)
RPC: 61 call_refresh (status 0)
RPC: 61 call_refreshresult (status 0)
RPC: 61 refreshing RPCSEC_GSS cred ffff88007a413cf0

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Cc: stable@vger.kernel.org # 2.6.37+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Handle connect errors ECONNABORTED and EHOSTUNREACH

Ensure that call_bind_status, call_connect_status, call_transmit_status and
call_status all are capable of handling ECONNABORTED and EHOSTUNREACH.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Avoid deep recursion in rpc_release_client

In cases where an rpc client has a parent hierarchy, then
rpc_free_client may end up calling rpc_release_client() on the
parent, thus recursing back into rpc_free_client. If the hierarchy
is deep enough, then we can get into situations where the stack
simply overflows.

The fix is to have rpc_release_client() loop so that it can take
care of the parent rpc client hierarchy without needing to
recurse.

Reported-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Weston Andros Adamson <dros@netapp.com>
Reported-by: Bruce Fields <bfields@fieldses.org>
Link: http://lkml.kernel.org/r/2C73011F-0939-434C-9E4D-13A1EB1403D7@netapp.com
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: remove duplicated include from clnt.c

Remove duplicated include.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add correct rcu_dereference annotation in rpc_clnt_set_transport

rpc_clnt_set_transport should use rcu_derefence_protected(), as it is
only safe to be called with the rpc_clnt::cl_lock held.

Cc: Chuck Lever <Chuck.Lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add a helper to switch the transport of an rpc_clnt

Add an RPC client API to redirect an rpc_clnt's transport from a
source server to a destination server during a migration event.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ cel: forward ported to 3.12 ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Modify synopsis of rpc_client_register()

The rpc_client_register() helper was added in commit e73f4cc0,
"SUNRPC: split client creation routine into setup and registration,"
Mon Jun 24 11:52:52 2013. In a subsequent patch, I'd like to invoke
rpc_client_register() from a context where a struct rpc_create_args
is not available.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: call_connect_status should recheck bind and connect status on error

Currently, we go directly to call_transmit which sends us to call_status
on error. If we know that the connect attempt failed, we should rather
just jump straight back to call_bind and call_connect.

Ditto for EAGAIN, except do not delay.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Fix RPC call retransmission statistics

A retransmit should be when you successfully transmit an RPC call to
the server a second time.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add RPC task and client level options to disable the resend timeout

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Clean up - convert xprt_prepare_transmit to return a bool

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add an identifier for struct rpc_clnt

Add an identifier in order to aid debugging.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC refactor rpcauth_checkverf error returns

Most of the time an error from the credops crvalidate function means the
server has sent us a garbage verifier. The gss_validate function is the
exception where there is an -EACCES case if the user GSS_context on the client
has expired.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: don't map EKEYEXPIRED to EACCES in call_refreshresult

The NFS layer needs to know when a key has expired.
This change also returns -EKEYEXPIRED to the application, and the informative
"Key has expired" error message is displayed. The user then knows that
credential renewal is required.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: rpcauth_create needs to know about rpc_clnt clone status

Ensure that we set rpc_clnt->cl_parent before calling rpc_client_register
so that rpcauth_create can find any existing RPCSEC_GSS caches for this
transport.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Remove the rpc_client->cl_dentry

It is now redundant.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Remove the obsolete auth-only interface for pipefs dentry management

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add a framework to clean up management of rpc_pipefs directories

The current system requires everyone to set up notifiers, manage directory
locking, etc.
What we really want to do is have the rpc_client create its directory,
and then create all the entries.

This patch will allow the RPCSEC_GSS and NFS code to register all the
objects that they want to have appear in the directory, and then have
the sunrpc code call them back to actually create/destroy their pipefs
dentries when the rpc_client creates/destroys the parent.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Replace clnt->cl_principal

The clnt->cl_principal is being used exclusively to store the service
target name for RPCSEC_GSS/krb5 callbacks. Replace it with something that
is stored only in the RPCSEC_GSS-specific code.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Cleanup rpc_setup_pipedir

The directory name is _always_ clnt->cl_program->pipe_dir_name.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Remove unused struct rpc_clnt field cl_protname

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Deprecate rpc_client->cl_protname

It just duplicates the cl_program->name, and is not used in any fast
paths where the extra dereference will cause a hit.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: If the rpcbind channel is disconnected, fail the call to unregister

If rpcbind causes our connection to the AF_LOCAL socket to close after
we've registered a service, then we want to be careful about reconnecting
since the mount namespace may have changed.

By simply refusing to reconnect the AF_LOCAL socket in the case of
unregister, we avoid the need to somehow save the mount namespace. While
this may lead to some services not unregistering properly, it should
be safe.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Nix <nix@esperi.org.uk>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org # 3.9.x

SUNRPC: Fix another issue with rpc_client_register()

Fix the error pathway if rpcauth_create() fails.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

rpc_create_*_dir: don't bother with qstr

just pass the name

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

SUNRPC: Fix a deadlock in rpc_client_register()

Commit 384816051ca9125cd54750e59c780c2a2655fa4f (SUNRPC: fix races on
PipeFS MOUNT notifications) introduces a regression when we call
rpc_setup_pipedir() with RPCSEC_GSS as the auth flavour.

By calling rpcauth_create() while holding the sn->pipefs_sb_lock, we
end up deadlocking in gss_pipes_dentries_create_net().
Fix is to register the client and release the mutex before calling
rpcauth_create().

Reported-by: Weston Andros Adamson <dros@netapp.com>
Tested-by: Weston Andros Adamson <dros@netapp.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: <stable@vger.kernel.org> # : 3848160: SUNRPC: fix races on PipeFS MOUNT
Cc: <stable@vger.kernel.org> # : e73f4cc: SUNRPC: split client creation
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: PipeFS MOUNT notification optimization for dying clients

Not need to create pipes for dying client. So just skip them.

Note: we can safely dereference the client structure, because notification
caller is holding sn->pipefs_sb_lock.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: split client creation routine into setup and registration

This helper moves all "registration" code to the new rpc_client_register()
helper.
This helper will be used later in the series to synchronize against PipeFS
MOUNT/UMOUNT events.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: fix races on PipeFS UMOUNT notifications

CPU#0 CPU#1
----------------------------- -----------------------------
rpc_kill_sb
sn->pipefs_sb = NULL rpc_release_client
(UMOUNT_EVENT) rpc_free_auth
rpc_pipefs_event
rpc_get_client_for_event
!atomic_inc_not_zero(cl_count)
<skip the client>
atomic_inc(cl_count)
rpc_free_client
rpc_clnt_remove_pipedir
<skip client dir removing>

To fix this, this patch does the following:

1) Calls RPC_PIPEFS_UMOUNT notification with sn->pipefs_sb_lock being held.
2) Removes SUNRPC client from the list AFTER pipes destroying.
3) Doesn't hold RPC client on notification: if client in the list, then it
can't be destroyed while sn->pipefs_sb_lock in hold by notification caller.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: fix races on PipeFS MOUNT notifications

Below are races, when RPC client can be created without PiepFS dentries

CPU#0 CPU#1
----------------------------- -----------------------------
rpc_new_client rpc_fill_super
rpc_setup_pipedir
mutex_lock(&sn->pipefs_sb_lock)
rpc_get_sb_net == NULL
(no per-net PipeFS superblock)
sn->pipefs_sb = sb;
notifier_call_chain(MOUNT)
(client is not in the list)
rpc_register_client
(client without pipes dentries)

To fix this patch:
1) makes PipeFS mount notification call with pipefs_sb_lock being held.
2) releases pipefs_sb_lock on new SUNRPC client creation only after
registration.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Don't spam syslog with "Pseudoflavor not found" messages

Just convert those messages to dprintk()s so that they can be used
when debugging.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add RPC based upcall mechanism for RPCGSS auth

This patch implements a sunrpc client to use the services of the gssproxy
userspace daemon.

In particular it allows to perform calls in user space using an RPC
call instead of custom hand-coded upcall/downcall messages.

Currently only accept_sec_context is implemented as that is all is needed for
the server case.

File server modules like NFS and CIFS can use full gssapi services this way,
once init_sec_context is also implemented.

For the NFS server case this code allow to lift the limit of max 2k krb5
tickets. This limit is prevents legitimate kerberos deployments from using krb5
authentication with the Linux NFS server as they have normally ticket that are
many kilobytes large.

It will also allow to lift the limitation on the size of the credential set
(uid,gid,gids) passed down from user space for users that have very many groups
associated. Currently the downcall mechanism used by rpc.svcgssd is limited
to around 2k secondary groups of the 65k allowed by kernel structures.

Signed-off-by: Simo Sorce <simo@redhat.com>
[bfields: containerization, concurrent upcalls, misc. fixes and cleanup]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: allow disabling idle timeout

In the gss-proxy case we don't want to have to reconnect at random--we
want to connect only on gss-proxy startup when we can steal gss-proxy's
context to do the connect in the right namespace.

So, provide a flag that allows the rpc_create caller to turn off the
idle timeout.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: Allow rpc_create() to request that TCP slots be unlimited

This is mainly for use by NFSv4.1, where the session negotiation
ultimately wants to decide how many RPC slots we can fill.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Fix a livelock problem in the xprt->backlog queue

This patch ensures that we throttle new RPC requests if there are
requests already waiting in the xprt->backlog queue. The reason for
doing this is to fix livelock issues that can occur when an existing
(high priority) task is waiting in the backlog queue, gets woken up
by xprt_free_slot(), but a new task then steals the slot.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Fix a potential memory leak in rpc_new_client

If the call to rpciod_up() fails, we currently leak a reference to the
struct rpc_xprt.
As part of the fix, we also remove the redundant check for xprt!=NULL.
This is already taken care of by the callers.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Remove extra xprt_put()

While testing error cases where rpc_new_client() fails, I saw
some oopses.

If rpc_new_client() fails, it already invokes xprt_put(). Thus
__rpc_clone_client() does not need to invoke it again.

Introduced by commit 1b63a751 "SUNRPC: Refactor rpc_clone_client()"
Fri Sep 14, 2012.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org [>=3.7]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Report network/connection errors correctly for SOFTCONN rpc tasks

In the case of a SOFTCONN rpc task, we really want to ensure that it
reports errors like ENETUNREACH back to the caller. Currently, only
some of these errors are being reported back (connect errors are not),
and they are being converted by the RPC layer into EIO.

Reported-by: Jan Engelhardt <jengelh@inai.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: One line comment fix

Reported-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: add call to get configured timeout

Returns the configured timeout for the xprt of the rpc client.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

sunrpc: move address copy/cmp/convert routines and prototypes from clnt.h to addr.h

These routines are used by server and client code, so having them in a
separate header would be best.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: Avoid RCU dereferences in the transport bind and connect code

Avoid an RCU dereference by removing task->tk_xprt

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Eliminate task->tk_xprt accesses that bypass rcu_dereference()

tk_xprt is just a shortcut for tk_client->cl_xprt, however cl_xprt is
defined as an __rcu variable. Replace dereferences of tk_xprt with
non-rcu dereferences where it is safe to do so.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: fix sunrpc/clnt.c kernel-doc warnings

Fix new kernel-doc warnings in clnt.c:

Warning(net/sunrpc/clnt.c:561): No description found for parameter 'flavor'
Warning(net/sunrpc/clnt.c:561): Excess function parameter 'auth' description in 'rpc_clone_client_set_auth'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

SUNRPC: Partial revert of commit 168e4b39d1afb79a7e3ea6c3bb246b4c82c6bdb9

Partially revert commit (SUNRPC: add WARN_ON_ONCE for potential deadlock).
The looping behaviour has been tracked down to a knownn issue with
workqueues, and a workaround has now been implemented.

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 [>= 3.7]

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

SUNRPC: Introduce rpc_clone_client_set_auth()

An ULP is supposed to be able to replace a GSS rpc_auth object with
another GSS rpc_auth object using rpcauth_create(). However,
rpcauth_create() in 3.5 reliably fails with -EEXIST in this case.
This is because when gss_create() attempts to create the upcall pipes,
sometimes they are already there. For example if a pipe FS mount
event occurs, or a previous GSS flavor was in use for this rpc_clnt.

It turns out that's not the only problem here. While working on a
fix for the above problem, we noticed that replacing an rpc_clnt's
rpc_auth is not safe, since dereferencing the cl_auth field is not
protected in any way.

So we're deprecating the ability of rpcauth_create() to switch an
rpc_clnt's security flavor during normal operation. Instead, let's
add a fresh API that clones an rpc_clnt and gives the clone a new
flavor before it's used.

This makes immediate use of the new __rpc_clone_client() helper.

This can be used in a similar fashion to rpcauth_create() when a
client is hunting for the correct security flavor. Instead of
replacing an rpc_clnt's security flavor in a loop, the ULP replaces
the whole rpc_clnt.

To fix the -EEXIST problem, any ULP logic that relies on replacing
an rpc_clnt's rpc_auth with rpcauth_create() must be changed to use
this API instead.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Refactor rpc_clone_client()

rpc_clone_client() does most of the same tasks as rpc_new_client(),
so there is an opportunity for code re-use. Create a generic helper
that makes it easy to clone an RPC client while replacing any of the
clnt's parameters.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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>

sunrpc: clnt: Add missing braces

Add a missing set of braces that commit 4e0038b6b24
("SUNRPC: Move clnt->cl_server into struct rpc_xprt")
forgot.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.4]

net: Fix (nearly-)kernel-doc comments for various functions

Fix incorrect start markers, wrapped summary lines, missing section
breaks, incorrect separators, and some name mismatches.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sunrpc: fix loss of task->tk_status after rpc_delay call in xprt_alloc_slot

xprt_alloc_slot will call rpc_delay() to make the task wait a bit before
retrying when it gets back an -ENOMEM error from xprt_dynamic_alloc_slot.
The problem is that rpc_delay will clear the task->tk_status, causing
call_reserveresult to abort the task.

The solution is simply to let call_reserveresult handle the ENOMEM error
directly.

Reported-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org [>= 3.1]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

vfs: make it possible to access the dentry hash/len as one 64-bit entry

This allows comparing hash and len in one operation on 64-bit
architectures. Right now only __d_lookup_rcu() takes advantage of this,
since that is the case we care most about.

The use of anonymous struct/unions hides the alternate 64-bit approach
from most users, the exception being a few cases where we initialize a
'struct qstr' with a static initializer. This makes the problematic
cases use a new QSTR_INIT() helper function for that (but initializing
just the name pointer with a "{ .name = xyzzy }" initializer remains
valid, as does just copying another qstr structure).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

SUNRPC: RPC client must use the current utsname hostname string

Now that the rpc client is namespace aware, it needs to use the
utsname of the process that created it instead of using the
init_utsname. Both rpc_new_client and rpc_clone_client need to
be fixed.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>

SUNRPC: traverse clients tree on PipeFS event

v2: recursion was replaced by loop

If client is a clone, then it's parent can not be in the list.
But parent's Pipefs dentries have to be created and destroyed.

Note: event skip helper for clients introduced

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: skip clients with program without PipeFS entries

1) This is sane.
2) Otherwise there will be soft lockup:

do {
rpc_get_client_for_event (clnt->cl_dentry == NULL ==> choose)
__rpc_pipefs_event (clnt->cl_program->pipe_dir_name == NULL ==> return)
} while (1)

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: skip dead but not buried clients on PipeFS events

These clients can't be safely dereferenced if their counter in 0.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Remove all #inclusions of asm/system.h

Remove all #inclusions of asm/system.h preparatory to splitting and killing
it. Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>

SUNRPC: Add API to acquire source address

NFSv4.0 clients must send endpoint information for their callback
service to NFSv4.0 servers during their first contact with a server.
Traditionally on Linux, user space provides the callback endpoint IP
address via the "clientaddr=" mount option.

During an NFSv4 migration event, it is possible that an FSID may be
migrated to a destination server that is accessible via a different
source IP address than the source server was. The client must update
callback endpoint information on the destination server so that it can
maintain leases and allow delegation.

Without a new "clientaddr=" option from user space, however, the
kernel itself must construct an appropriate IP address for the
callback update. Provide an API in the RPC client for upper layer
RPC consumers to acquire a source address for a remote.

The mechanism used by the mount.nfs command is copied: set up a
connected UDP socket to the designated remote, then scrape the source
address off the socket. We are careful to select the correct network
namespace when setting up the temporary UDP socket.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Move clnt->cl_server into struct rpc_xprt

When the cl_xprt field is updated, the cl_server field will also have
to change. Since the contents of cl_server follow the remote endpoint
of cl_xprt, just move that field to the rpc_xprt.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ cel: simplify check_gss_callback_principal(), whitespace changes ]
[ cel: forward ported to 3.4 ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Use RCU to dereference the rpc_clnt.cl_xprt field

A migration event will replace the rpc_xprt used by an rpc_clnt. To
ensure this can be done safely, all references to cl_xprt must now use
a form of rcu_dereference().

Special care is taken with rpc_peeraddr2str(), which returns a pointer
to memory whose lifetime is the same as the rpc_xprt.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ cel: fix lockdep splats and layering violations ]
[ cel: forward ported to 3.4 ]
[ cel: remove rpc_max_reqs(), add rpc_net_ns() ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>