Chris Worley reports:
 RIP: 0010:[<ffffffffa0245f80>]  [<ffffffffa0245f80>] rpc_new_client+0x2a0/0x2e0 [sunrpc]
 RSP: 0018:ffff880158f6f548  EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff880234f8bc00 RCX: 000000000000ea60
 RDX: 0000000000074cc0 RSI: 000000000000ea60 RDI: ffff880234f8bcf0
 RBP: ffff880158f6f588 R08: 000000000001ac80 R09: ffff880237003300
 R10: ffff880201171000 R11: ffffea0000d75200 R12: ffffffffa03afc60
 R13: ffff880230c18800 R14: 0000000000000000 R15: ffff880158f6f680
 FS:  00007f0e32673740(0000) GS:ffff88023fc40000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 0000000000000008 CR3: 0000000234886000 CR4: 00000000001406e0
 Stack:
  ffffffffa047a680 0000000000000000 ffff880158f6f598 ffff880158f6f680
  ffff880158f6f680 ffff880234d11d00 ffff88023357f800 ffff880158f6f7d0
  ffff880158f6f5b8 ffffffffa024660a ffff880158f6f5b8 ffffffffa02492ec
 Call Trace:
  [<ffffffffa024660a>] rpc_create_xprt+0x1a/0xb0 [sunrpc]
  [<ffffffffa02492ec>] ? xprt_create_transport+0x13c/0x240 [sunrpc]
  [<ffffffffa0246766>] rpc_create+0xc6/0x1a0 [sunrpc]
  [<ffffffffa038e695>] nfs_create_rpc_client+0xf5/0x140 [nfs]
  [<ffffffffa038f31a>] nfs_init_client+0x3a/0xd0 [nfs]
  [<ffffffffa038f22f>] nfs_get_client+0x25f/0x310 [nfs]
  [<ffffffffa025cef8>] ? rpc_ntop+0xe8/0x100 [sunrpc]
  [<ffffffffa047512c>] nfs3_set_ds_client+0xcc/0x100 [nfsv3]
  [<ffffffffa041fa10>] nfs4_pnfs_ds_connect+0x120/0x400 [nfsv4]
  [<ffffffffa03d41c7>] nfs4_ff_layout_prepare_ds+0xe7/0x330 [nfs_layout_flexfiles]
  [<ffffffffa03d1b1b>] ff_layout_pg_init_write+0xcb/0x280 [nfs_layout_flexfiles]
  [<ffffffffa03a14dc>] __nfs_pageio_add_request+0x12c/0x490 [nfs]
  [<ffffffffa03a1fa2>] nfs_pageio_add_request+0xc2/0x2a0 [nfs]
  [<ffffffffa03a0365>] ? nfs_pageio_init+0x75/0x120 [nfs]
  [<ffffffffa03a5b50>] nfs_do_writepage+0x120/0x270 [nfs]
  [<ffffffffa03a5d31>] nfs_writepage_locked+0x61/0xc0 [nfs]
  [<ffffffff813d4115>] ? __percpu_counter_add+0x55/0x70
  [<ffffffffa03a6a9f>] nfs_wb_single_page+0xef/0x1c0 [nfs]
  [<ffffffff811ca4a3>] ? __dec_zone_page_state+0x33/0x40
  [<ffffffffa0395b21>] nfs_launder_page+0x41/0x90 [nfs]
  [<ffffffff811baba0>] invalidate_inode_pages2_range+0x340/0x3a0
  [<ffffffff811bac17>] invalidate_inode_pages2+0x17/0x20
  [<ffffffffa039960e>] nfs_release+0x9e/0xb0 [nfs]
  [<ffffffffa0399570>] ? nfs_open+0x60/0x60 [nfs]
  [<ffffffffa0394dad>] nfs_file_release+0x3d/0x60 [nfs]
  [<ffffffff81226e6c>] __fput+0xdc/0x1e0
  [<ffffffff81226fbe>] ____fput+0xe/0x10
  [<ffffffff810bf2e4>] task_work_run+0xc4/0xe0
  [<ffffffff810a4188>] do_exit+0x2e8/0xb30
  [<ffffffff8102471c>] ? do_audit_syscall_entry+0x6c/0x70
  [<ffffffff811464e6>] ? __audit_syscall_exit+0x1e6/0x280
  [<ffffffff810a4a5f>] do_group_exit+0x3f/0xa0
  [<ffffffff810a4ad4>] SyS_exit_group+0x14/0x20
  [<ffffffff8179b76e>] system_call_fastpath+0x12/0x71

Which seems to be due to a call to utsname() when in a task exit context
in order to determine the hostname to set in rpc_new_client().

In reality, what we want here is not the hostname of the current task, but
the hostname that was used to set up the metadata server.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If clp->cl_cb_ident is zero, then nfs_cb_idr_remove_locked() skips removing
it when the nfs_client is freed.  A decoding or server bug can then find
and try to put that first nfs_client which would lead to a crash.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Fixes: d6870312 ("nfs4client: convert to idr_alloc()")
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

They already exist and do the exact same thing.  Let's save ourselves
several lines of code!
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Commit 7b1f1fd1 "NFSv4/4.1: Fix bugs in nfs4[01]_walk_client_list"
have change the logical of the list_for_each_entry().
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This file is only used internally to the NFS v4 module, so it doesn't
need to be in the global include path.  I also renamed it from
nfs_idmap.h to nfs4idmap.h to emphasize that it's an NFSv4-only include
file.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We do not want to allow a race with another NFS mount to cause
nfs41_walk_client_list() to establish a lease on our nfs_client before
we're done checking for trunking.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

flexfile layout may need to set such when making DS connections.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

flexfile layout may use different auth flavor as specified by MDS.
Reviewed-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

If we start state recovery on a client that failed to initialise correctly,
then we are very likely to Oops.
Reported-by: N"Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>
Link: http://lkml.kernel.org/r/130621862.279655.1421851650684.JavaMail.zimbra@desy.de
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Detect server trunking across transport protocols. Otherwise, an
RDMA mount and a TCP mount of the same server will end up with
separate nfs_clients using the same clientid4.
Reported-by: NDai Ngo <dai.ngo@oracle.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

While we normally expect the NFSv4 client to always send the same client
owner to all servers, there are a couple of situations where that is not
the case:
 1) In NFSv4.0, switching between use of '-omigration' and not will cause
    the kernel to switch between using the non-uniform and uniform client
    strings.
 2) In NFSv4.1, or NFSv4.0 when using uniform client strings, if the
    uniquifier string is suddenly changed.

This patch will catch those situations by checking the client owner id
in the trunking detection code, and will do the right thing if it notices
that the strings differ.

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

Ensure that we cache the NFSv4/v4.1 client owner_id so that we can
verify it when we're doing trunking detection.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Currently, our trunking code will check for session trunking, but will
fail to detect client id trunking. This is a problem, because it means
that the client will fail to recognise that the two connections represent
shared state, even if they do not permit a shared session.
By removing the check for the server minor id, and only checking the
major id, we will end up doing the right thing in both cases: we close
down the new nfs_client and fall back to using the existing one.

Fixes: 05f4c350 ("NFS: Discover NFSv4 server trunking when mounting")
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org # 3.7.x
Tested-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

nfs4_init_callback() is never invoked for NFS versions other than 4.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The nfs_put_client() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

There is a race between nfs4_state_manager() and
nfs_server_remove_lists() that happens during a nfsv3 mount.

The v3 mount notices there is already a supper block so
nfs_server_remove_lists() called which uses the nfs_client_lock
spin lock to synchronize access to the client list.

At the same time nfs4_state_manager() is running through
the client list looking for work to do, using the same
lock. When nfs4_state_manager() wins the race to the
list, a v3 client pointer is found and not ignored
properly which causes the panic.

Moving some protocol checks before the state checking
avoids the panic.

CC: Stable Tree <stable@vger.kernel.org>
Signed-off-by: NSteve Dickson <steved@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We reference cl_hostname in many places for debugging purpose.
So make it useful by setting hostname when calling nfs_get_client.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If a timeout or a signal interrupts the NFSv4 trunking discovery
SETCLIENTID_CONFIRM call, then we don't know whether or not the
server has changed the callback identifier on us.
Assume that it did, and schedule a 'path down' recovery...
Tested-by: NSteve Dickson <steved@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We need to use the same net namespace that was used to resolve
the hostname and sockaddr arguments.

Fixes: 32e62b7c (NFS: Add nfs4_update_server)
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

There may still be timers active on the session waitqueues. Make sure
that we kill them before freeing the memory.

Cc: stable@vger.kernel.org # 3.12+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The original printk() made sense when the GSSAPI codepaths were called
only when sec=krb5* was explicitly requested. Now however, in many cases
the nfs client will try to acquire GSSAPI credentials by default, even
when it's not requested.

Since we don't have a great mechanism to distinguish between the two
cases, just turn the pr_warn into a dprintk instead. With this change we
can also get rid of the ratelimiting.

We do need to keep the EXPORT_SYMBOL(gssd_running) in place since
auth_gss.ko needs it and sunrpc.ko provides it. We can however,
eliminate the gssd_running call in the nfs code since that's a bit of a
layering violation.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If clp is new (cl_count = 1) and it matches another client in
nfs4_discover_server_trunking, the nfs_put_client will free clp before
->cl_preserve_clid is set.

Cc: stable@vger.kernel.org # 3.7+
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Both nfs41_walk_client_list and nfs40_walk_client_list expect the
'status' variable to be set to the value -NFS4ERR_STALE_CLIENTID
if the loop fails to find a match.
The problem is that the 'pos->cl_cons_state > NFS_CS_READY' changes
the value of 'status', and sets it either to the value '0' (which
indicates success), or to the value EINTR.

Cc: stable@vger.kernel.org # 3.7.x: 7b1f1fd1: NFSv4/4.1: Fix bugs in
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Currently, the client will attempt to use krb5i in the SETCLIENTID call
even if rpc.gssd isn't running. When that fails, it'll then fall back to
RPC_AUTH_UNIX. This introduced a delay when mounting if rpc.gssd isn't
running, and causes warning messages to pop up in the ring buffer.

Check to see if rpc.gssd is running before even attempting to use krb5i
auth, and just silently skip trying to do so if it isn't. In the event
that the admin is actually trying to mount with krb5*, it will still
fail at a later stage of the mount attempt.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch adds support for multiple security options which can be
specified using a colon-delimited list of security flavors (the same
syntax as nfsd's exports file).

This is useful, for instance, when NFSv4.x mounts cross SECINFO
boundaries. With this patch a user can use "sec=krb5i,krb5p"
to mount a remote filesystem using krb5i, but can still cross
into krb5p-only exports.

New mounts will try all security options before failing.  NFSv4.x
SECINFO results will be compared against the sec= flavors to
find the first flavor in both lists or if no match is found will
return -EPERM.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Since the parsed sec= flavor is now stored in nfs_server->auth_info,
we no longer need an nfs_server flag to determine if a sec= option was
used.

This flag has not been completely removed because it is still needed for
the (old but still supported) non-text parsed mount options ABI
compatability.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Cache the auth_info structure in nfs_server and pass these values to submounts.

This lays the groundwork for supporting multiple sec= options.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When filling parsed_mount_data, store the parsed sec= mount option in
the new struct nfs_auth_info and the chosen flavor in selected_flavor.

This patch lays the groundwork for supporting multiple sec= options.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Migration recovery and state recovery must be serialized, so handle
both in the state manager thread.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Allow code in nfsv4.ko to use _nfs_display_fhandle().
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

New function nfs4_update_server() moves an nfs_server to a different
nfs_client.  This is done as part of migration recovery.

Though it may be appealing to think of them as the same thing,
migration recovery is not the same as following a referral.

For a referral, the client has not descended into the file system
yet: it has no nfs_server, no super block, no inodes or open state.
It is enough to simply instantiate the nfs_server and super block,
and perform a referral mount.

For a migration, however, we have all of those things already, and
they have to be moved to a different nfs_client.  No local namespace
changes are needed here.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The spec states that the client should not resend requests because
the server will disconnect if it needs to drop an RPC request.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In cases where the parent super block was not mounted with a 'sec=' line,
allow autonegotiation of security for the submounts.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

NFSv4 security auto-negotiation has been broken since
commit 4580a92d (NFS:
Use server-recommended security flavor by default (NFSv3))
because nfs4_try_mount() will automatically select AUTH_SYS
if it sees no auth flavours.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>

Commit 4edaa308 "NFS: Use "krb5i" to establish NFSv4 state whenever possible"
uses the nfs_client cl_rpcclient for all state management operations, and
will use krb5i or auth_sys with no regard to the mount command authflavor
choice.

The MDS, as any NFSv4.1 mount point, uses the nfs_server rpc client for all
non-state management operations with a different nfs_server for each fsid
encountered traversing the mount point, each with a potentially different
auth flavor.

pNFS data servers are not mounted in the normal sense as there is no associated
nfs_server structure. Data servers can also export multiple fsids, each with
a potentially different auth flavor.

Data servers need to use the same authflavor as the MDS server rpc client for
non-state management operations. Populate a list of rpc clients with the MDS
server rpc client auth flavor for the DS to use.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Anchor an nfs4_slot_table in the nfs_client for use with NFSv4.0
transport blocking.  It is initialized only for NFSv4.0 nfs_client's.

Introduce appropriate minor version ops to handle nfs_client
initialization and shutdown requirements that differ for each minor
version.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

NFS_CS_MIGRATION makes sense only for NFSv4 mounts.  Introduced by
commit 89652617 (NFS: Introduce "migration" mount option) Fri Sep 14
17:24:11 2012.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

nfs4_init_session was originally written to be called prior to
nfs4_init_channel_attrs, setting the session target_max response and request
sizes that nfs4_init_channel_attrs would pay attention to.

In the current code flow, nfs4_init_session, just like nfs4_init_ds_session
for the data server case, is called after the session is all negotiated, and
is actually used in a RECLAIM COMPLETE call to the server.

Remove the un-needed fc_target_max response and request fields from
nfs4_session and just set the max_resp_sz and max_rqst_sz in
nfs4_init_channel_attrs.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>