Clean up: There's little chance of contention between the use of
rb_lock and rb_reqslock, so merge the two. This avoids having to
take both in some (possibly future) cases.

Transport tear-down is already serialized, thus there is no need for
locking at all when destroying rpcrdma_reqs.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

For better observability of parsing errors, return the error code
generated in the decoders to the upper layer consumer.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Since commit ffe1f0df ("rpcrdma: Merge svcrdma and xprtrdma
modules into one"), the forward and backchannel components are part
of the same kernel module. A separate request_module() call in the
backchannel code is no longer necessary.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Commit 431f6eb3 ("SUNRPC: Add a label for RPC calls that require
allocation on receive") didn't update similar logic in rpc_rdma.c.
I don't think this is a bug, per-se; the commit just adds more
careful checking for broken upper layer behavior.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Having to specify "proto=rdma,port=20049" is cumbersome.

RFC 8267 Section 6.3 requires NFSv4 clients to use "the alternative
well-known port number", which is 20049. Make the use of the well-
known port number automatic, just as it is for NFS/TCP and port
2049.

For NFSv2/3, Section 4.2 allows clients to simply choose 20049 as
the default or use rpcbind. I don't know of an NFS/RDMA server
implementation that registers it's NFS/RDMA service with rpcbind,
so automatically choosing 20049 seems like the better choice. The
other widely-deployed NFS/RDMA client, Solaris, also uses 20049
as the default port.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Place the associated RPC transaction's XID in the upper 32 bits of
each RDMA segment's rdma_offset field. There are two reasons to do
this:

- The R_key only has 8 bits that are different from registration to
  registration. The XID adds more uniqueness to each RDMA segment to
  reduce the likelihood of a software bug on the server reading from
  or writing into memory it's not supposed to.

- On-the-wire RDMA Read and Write requests do not otherwise carry
  any identifier that matches them up to an RPC. The XID in the
  upper 32 bits will act as an eye-catcher in network captures.
Suggested-by: Tom Talpey <ttalpey@microsoft.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: Now that there is only FRWR, there is no need for a memory
registration switch. The indirect calls to the memreg operations can
be replaced with faster direct calls.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

FMR is not supported on most recent RDMA devices. It is also less
secure than FRWR because an FMR memory registration can expose
adjacent bytes to remote reading or writing. As discussed during the
RDMA BoF at LPC 2018, it is time to remove support for FMR in the
NFS/RDMA client stack.

Note that NFS/RDMA server-side uses either local memory registration
or FRWR. FMR is not used.

There are a few Infiniband/RoCE devices in the kernel tree that do
not appear to support MEM_MGT_EXTENSIONS (FRWR), and therefore will
not support client-side NFS/RDMA after this patch. These are:

 - mthca
 - qib
 - hns (RoCE)

Users of these devices can use NFS/TCP on IPoIB instead.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Some devices advertise a large max_fast_reg_page_list_len
capability, but perform optimally when MRs are significantly smaller
than that depth -- probably when the MR itself is no larger than a
page.

By default, the RDMA R/W core API uses max_sge_rd as the maximum
page depth for MRs. For some devices, the value of max_sge_rd is
1, which is also not optimal. Thus, when max_sge_rd is larger than
1, use that value. Otherwise use the value of the
max_fast_reg_page_list_len attribute.

I've tested this with CX-3 Pro, FastLinq, and CX-5 devices. It
reproducibly improves the throughput of large I/Os by several
percent.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

With certain combinations of krb5i/p, MR size, and r/wsize, I/O can
fail with EMSGSIZE. This is because the calculated value of
ri_max_segs (the max number of MRs per RPC) exceeded
RPCRDMA_MAX_HDR_SEGS, which caused Read or Write list encoding to
walk off the end of the transport header.

Once that was addressed, the ro_maxpages result has to be corrected
to account for the number of MRs needed for Reply chunks, which is
2 MRs smaller than a normal Read or Write chunk.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Transport disconnect processing does a "wake pending tasks" at
various points.

Suppose an RPC Reply is being processed. The RPC task that Reply
goes with is waiting on the pending queue. If a disconnect wake-up
happens before reply processing is done, that reply, even if it is
good, is thrown away, and the RPC has to be sent again.

This window apparently does not exist for socket transports because
there is a lock held while a reply is being received which prevents
the wake-up call until after reply processing is done.

To resolve this, all RPC replies being processed on an RPC-over-RDMA
transport have to complete before pending tasks are awoken due to a
transport disconnect.

Callers that already hold the transport write lock may invoke
->ops->close directly. Others use a generic helper that schedules
a close when the write lock can be taken safely.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

After thinking about this more, and auditing other kernel ULP imple-
mentations, I believe that a DISCONNECT cm_event will occur after a
fatal QP event. If that's the case, there's no need for an explicit
disconnect in the QP event handler.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

To address a connection-close ordering problem, we need the ability
to drain the RPC completions running on rpcrdma_receive_wq for just
one transport. Give each transport its own RPC completion workqueue,
and drain that workqueue when disconnecting the transport.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: Divide the work cleanly:

- rpcrdma_wc_receive is responsible only for RDMA Receives
- rpcrdma_reply_handler is responsible only for RPC Replies
- the posted send and receive counts both belong in rpcrdma_ep
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The recovery case in frwr_op_unmap_sync needs to DMA unmap each MR.
frwr_release_mr does not DMA-unmap, but the recycle worker does.

Fixes: 61da886b ("xprtrdma: Explicitly resetting MRs is ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

While chasing yet another set of DMAR fault reports, I noticed that
the frwr recycler conflates whether or not an MR has been DMA
unmapped with frwr->fr_state. Actually the two have only an indirect
relationship. It's in fact impossible to guess reliably whether the
MR has been DMA unmapped based on its fr_state field, especially as
the surrounding code and its assumptions have changed over time.

A better approach is to track the DMA mapping status explicitly so
that the recycler is less brittle to unexpected situations, and
attempts to DMA-unmap a second time are prevented.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org # v4.20
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This patch removes the check from nfs_compare_mount_options to see if a
`sec' option was passed for the current mount before comparing auth
flavors and instead just always compares auth flavors.

Consider the following scenario:

You have a server with the address 192.168.1.1 and two exports /export/a
and /export/b.  The first export supports `sys' and `krb5' security, the
second just `sys'.

Assume you start with no mounts from the server.

The following results in EIOs being returned as the kernel nfs client
incorrectly thinks it can share the underlying `struct nfs_server's:

$ mkdir /tmp/{a,b}
$ sudo mount -t nfs -o vers=3,sec=krb5 192.168.1.1:/export/a /tmp/a
$ sudo mount -t nfs -o vers=3          192.168.1.1:/export/b /tmp/b
$ df >/dev/null
df: ‘/tmp/b’: Input/output error
Signed-off-by: Chris Perl <cperl@janestreet.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Just use ->cr_cred->fsuid directly.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1/ discard 'struct unx_cred'.  We don't need any data that
   is not already in 'struct rpc_cred'.
2/ Don't keep these creds in a hash table.  When a credential
   is needed, simply allocate it.  When not needed, discard it.
   This can easily be faster than performing a lookup on
   a shared hash table.
   As the lookup can happen during write-out, use a mempool
   to ensure forward progress.
   This means that we cannot compare two credentials for
   equality by comparing the pointers, but we never do that anyway.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This now always just does get_rpccred(), so we
don't need an operation pointer to know to do that.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This is no longer used.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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>

Use the common 'struct cred' to pass credentials for readdir.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Rather than keying the access cache with 'struct rpc_cred',
use 'struct cred'.  Then use cred_fscmp() to compare
credentials rather than comparing the raw pointer.

A benefit of this approach is that in the common case we avoid the
rpc_lookup_cred_nonblock() call which can be slow when the cred cache is large.
This also keeps many fewer items pinned in the rpc cred cache, so the
cred cache is less likely to get large.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This is no longer used.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS needs to know when a credential is about to expire so that
it can modify write-back behaviour to finish the write inside the
expiry time.
It currently uses functions in SUNRPC code which make use of a
fairly complex callback scheme and flags in the generic credientials.

As I am working to discard the generic credentials, this has to change.

This patch moves the logic into NFS, in part by finding and caching
the low-level credential in the open_context.  We then make direct
cred-api calls on that.

This makes the code much simpler and removes a dependency on generic
rpc credentials.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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>

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>

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>

it is never used.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This lock is no longer necessary.

If nfs4_get_renew_cred() needs to hunt through the open-state
creds for a user cred, it still takes the lock to stablize
the rbtree, but otherwise there are no races.

Note that this completely removes the lock from nfs4_renew_state().
It appears that the original need for the locking here was removed
long ago, and there is no longer anything to protect.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4 state management tries a root credential when no machine
credential is available, as can happen with kerberos.
It does this by replacing the cl_machine_cred with a root credential.
This means that any user of the machine credential needs to take
a lock while getting a reference to the machine credential, which is
a little cumbersome.

So introduce an explicit cl_root_cred, and never free either
credential until client shutdown.  This means that no locking
is needed to reference these credentials.  Future patches
will make use of this.

This is only a temporary addition.  both cl_machine_cred and
cl_root_cred will disappear later in the series.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The cred is a machine_cred iff ->principal is set, so there is no
need for the extra flag.

There is one case which deserves some
explanation. nfs4_root_machine_cred() calls rpc_lookup_machine_cred()
with a NULL principal name which results in not getting a machine
credential, but getting a root credential instead.
This appears to be what is expected of the caller, and is
clearly the result provided by both auth_unix and auth_gss
which already ignore the flag.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Use cred->fsuid and cred->fsgid instead.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

We can use cred->groupinfo (from the 'struct cred') instead.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The SUNRPC credential framework was put together before
Linux has 'struct cred'.  Now that we have it, it makes sense to
use it.
This first step just includes a suitable 'struct cred *' pointer
in every 'struct auth_cred' and almost every 'struct rpc_cred'.

The rpc_cred used for auth_null has a NULL 'struct cred *' as nothing
else really makes sense.

For rpc_cred, the pointer is reference counted.
For auth_cred it isn't.  struct auth_cred are either allocated on
the stack, in which case the thread owns a reference to the auth,
or are part of 'struct generic_cred' in which case gc_base owns the
reference, and "acred" shares it.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

It is common practice for helpers like this to silently,
accept a NULL pointer.
get_rpccred() and put_rpccred() used by NFS act this way
and using the same interface will ease the conversion
for NFS, and simplify the resulting code.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

There is no reason that modules should not be able
to use this, and NFS will need it when converted to
use 'struct cred'.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Sometimes we want to opportunistically get a
ref to a cred in an rcu_read_lock protected section.
get_task_cred() does this, and NFS does as similar thing
with its own credential structures.
To prepare for NFS converting to use 'struct cred' more
uniformly, define get_cred_rcu(), and use it in
get_task_cred().
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS needs to compare to credentials, to see if they can
be treated the same w.r.t. filesystem access.  Sometimes
an ordering is needed when credentials are used as a key
to an rbtree.
NFS currently has its own private credential management from
before 'struct cred' existed.  To move it over to more consistent
use of 'struct cred' we need a comparison function.
This patch adds that function.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>