Sparse identified an execution path in nfs41_walk_client_list()
where the nfs_client_lock is not re-acquired before taking the next
loop iteration.

fs/nfs/nfs4client.c:437:9: sparse: context imbalance in
 'nfs41_walk_client_list' - different lock contexts for basic block
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

If the layoutget call returns a stateid error, we want to invalidate the
layout stateid, and/or recover the open stateid.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Sparse warning:
fs/nfs/nfs4getroot.c:11:5: warning: symbol 'nfs4_get_rootfh' was not declared.
Should it be static?
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Sparse warnings:
fs/nfs/nfs4sysctl.c:56:5: warning: symbol 'nfs4_register_sysctl' was not
declared. Should it be static?
fs/nfs/nfs4sysctl.c:64:6: warning: symbol 'nfs4_unregister_sysctl' was not
declared. Should it be static?
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Sparse warning:
fs/nfs/super.c:2517:15: warning: symbol 'nfs_xdev_mount' was not declared.
Should it be static?
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Sparse warning:
fs/nfs/super.c:2638:16: sparse: symbol 'nfs_callback_tcpport' was not
declared. Should it be static?
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Build error:
fs/nfs/netns.h:27:15: error: 'NFS4_MAX_MINOR_VERSION' undeclared here (not in
a function)
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

We should reclaim reboot state when the clientid is stale.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Fix another compiler warning.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

The current spaghetti code confuses some versions of gcc (and just
looks ugly as hell)! Clean up...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs_callback_tcpport is now per-net_namespace.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

[nfs] replace strict_str* with kstr* variants

 * replace string conversions with newer kstr* functions
Signed-off-by: Daniel Walter <sahne@0x90.at>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

There are some unnecessary semicolons in function find_nfs_version. Just remove them.
Signed-off-by: Yanchuan Nian <ycnian@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Using list_move_tail() instead of list_del() + list_add_tail().

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

For DIO writes, if it is not blocksize aligned, we need to do
internal serialization. It may slow down writers anyway. So we
just bail them out and resend to MDS.

Cc: stable <stable@vger.kernel.org> [since v3.4]
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

For DIO read, if it is not sector aligned, we should reject it
and resend via MDS. Otherwise there might be data corruption.
Also teach bl_read_pagelist to handle partial page reads for DIO.

Cc: stable <stable@vger.kernel.org> [since v3.4]
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

If applications use flock to protect its write range, generic NFS
will not do read-modify-write cycle at page cache level. Therefore
LD should know how to handle non-sector aligned writes. Otherwise
there will be data corruption.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

This reverts commit 159e0561, in favor
of a more complete fix to the alignment issue.
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

After commit e38eb650 (NFS: set_pnfs_layoutdriver() from
nfs4_proc_fsinfo()), set_pnfs_layoutdriver() is called inside
nfs4_proc_fsinfo(), but pnfs_blksize is not set. It causes setting
blocklayoutdriver failure and pnfsblock mount failure.

Cc: stable <stable@vger.kernel.org> [since v3.5]
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

pnfs_within_mdsthreshold() is called inside pg_init. We need to set
read_io/write_io before that. Otherwise we fail pnfs_within_mdsthreshold()
and IO goes to MDS.
A simple test case:
dd if=foo of=/mnt/pnfs/bar bs=10M count=1 oflag=direct
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

An optional boot parameter is introduced to allow client
administrators to specify a string that the Linux NFS client can
insert into its nfs_client_id4 id string, to make it both more
globally unique, and to ensure that it doesn't change even if the
client's nodename changes.

If this boot parameter is not specified, the client's nodename is
used, as before.

Client installation procedures can create a unique string (typically,
a UUID) which remains unchanged during the lifetime of that client
instance.  This works just like creating a UUID for the label of the
system's root and boot volumes.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

"Server trunking" is a fancy named for a multi-homed NFS server.
Trunking might occur if a client sends NFS requests for a single
workload to multiple network interfaces on the same server.  There
are some implications for NFSv4 state management that make it useful
for a client to know if a single NFSv4 server instance is
multi-homed.  (Note this is only a consideration for NFSv4, not for
legacy versions of NFS, which are stateless).

If a client cares about server trunking, no NFSv4 operations can
proceed until that client determines who it is talking to.  Thus
server IP trunking discovery must be done when the client first
encounters an unfamiliar server IP address.

The nfs_get_client() function walks the nfs_client_list and matches
on server IP address.  The outcome of that walk tells us immediately
if we have an unfamiliar server IP address.  It invokes
nfs_init_client() in this case.  Thus, nfs4_init_client() is a good
spot to perform trunking discovery.

Discovery requires a client to establish a fresh client ID, so our
client will now send SETCLIENTID or EXCHANGE_ID as the first NFS
operation after a successful ping, rather than waiting for an
application to perform an operation that requires NFSv4 state.

The exact process for detecting trunking is different for NFSv4.0 and
NFSv4.1, so a minorversion-specific init_client callout method is
introduced.

CLID_INUSE recovery is important for the trunking discovery process.
CLID_INUSE is a sign the server recognizes the client's nfs_client_id4
id string, but the client is using the wrong principal this time for
the SETCLIENTID operation.  The SETCLIENTID must be retried with a
series of different principals until one works, and then the rest of
trunking discovery can proceed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Currently, when identifying itself to NFS servers, the Linux NFS
client uses a unique nfs_client_id4.id string for each server IP
address it talks with.  For example, when client A talks to server X,
the client identifies itself using a string like "AX".  The
requirements for these strings are specified in detail by RFC 3530
(and bis).

This form of client identification presents a problem for Transparent
State Migration.  When client A's state on server X is migrated to
server Y, it continues to be associated with string "AX."  But,
according to the rules of client string construction above, client
A will present string "AY" when communicating with server Y.

Server Y thus has no way to know that client A should be associated
with the state migrated from server X.  "AX" is all but abandoned,
interfering with establishing fresh state for client A on server Y.

To support transparent state migration, then, NFSv4.0 clients must
instead use the same nfs_client_id4.id string to identify themselves
to every NFS server; something like "A".

Now a client identifies itself as "A" to server X.  When a file
system on server X transitions to server Y, and client A identifies
itself as "A" to server Y, Y will know immediately that the state
associated with "A," whether it is native or migrated, is owned by
the client, and can merge both into a single lease.

As a pre-requisite to adding support for NFSv4 migration to the Linux
NFS client, this patch changes the way Linux identifies itself to NFS
servers via the SETCLIENTID (NFSv4 minor version 0) and EXCHANGE_ID
(NFSv4 minor version 1) operations.

In addition to removing the server's IP address from nfs_client_id4,
the Linux NFS client will also no longer use its own source IP address
as part of the nfs_client_id4 string.  On multi-homed clients, the
value of this address depends on the address family and network
routing used to contact the server, thus it can be different for each
server.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Currently, the Linux client uses a unique nfs_client_id4.id string
when identifying itself to distinct NFS servers.

To support transparent state migration, the Linux client will have to
use the same nfs_client_id4 string for all servers it communicates
with (also known as the "uniform client string" approach).  Otherwise
NFS servers can not recognize that open and lock state need to be
merged after a file system transition.

Unfortunately, there are some NFSv4.0 servers currently in the field
that do not tolerate the uniform client string approach.

Thus, by default, our NFSv4.0 mounts will continue to use the current
approach, and we introduce a mount option that switches them to use
the uniform model.  Client administrators must identify which servers
can be mounted with this option.  Eventually most NFSv4.0 servers will
be able to handle the uniform approach, and we can change the default.

The first mount of a server controls the behavior for all subsequent
mounts for the lifetime of that set of mounts of that server.  After
the last mount of that server is gone, the client erases the data
structure that tracks the lease.  A subsequent lease may then honor
a different "migration" setting.

This patch adds only the infrastructure for parsing the new mount
option.  Support for uniform client strings is added in a subsequent
patch.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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>

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>

Clean up: Some function names have changed, but debugging messages
were never updated.  Automate the construction of the function name
in debugging messages.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Clean up: The blank space in front of the message must be spaces.
Tabs show up on the console as a graphical character.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

If the state manager thread is not actually able to fully recover from
some situation, it wakes up waiters, who kick off a new state manager
thread.  Quite often the fresh invocation of the state manager is just
as successful.

This results in a livelock as the client dumps thousands of NFS
requests a second on the network in a vain attempt to recover.  Not
very friendly.

To mitigate this situation, add a delay in the state manager after
an unhandled error, so that the client sends just a few requests
every second in this case.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/super.c: In function ‘nfs_compare_remount_data’:
fs/nfs/super.c:2042:18: warning: comparison between signed and
    unsigned integer expressions [-Wsign-compare]
fs/nfs/super.c:2043:18: warning: comparison between signed and
    unsigned integer expressions [-Wsign-compare]
fs/nfs/super.c:2044:20: warning: comparison between signed and
    unsigned integer expressions [-Wsign-compare]
fs/nfs/super.c:2046:21: warning: comparison between signed and
    unsigned integer expressions [-Wsign-compare]
fs/nfs/super.c:2047:21: warning: comparison between signed and
    unsigned integer expressions [-Wsign-compare]
fs/nfs/super.c:2048:21: warning: comparison between signed and
    unsigned integer expressions [-Wsign-compare]
fs/nfs/super.c:2049:21: warning: comparison between signed and
    unsigned integer expressions [-Wsign-compare]
fs/nfs/super.c:2050:18: warning: comparison between signed and
    unsigned integer expressions [-Wsign-compare]

Seen with gcc (GCC) 4.6.3 20120306 (Red Hat 4.6.3-2).
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NSM RPC client can be required on NFSv3 umount, when child reaper is dying
(and destroying it's mount namespace). It means, that current nsproxy is set
to NULL already, but creation of RPC client requires UTS namespace for gaining
hostname string.

This patch creates reference-counted per-net NSM client on first monitor
request and destroys it after last unmonitor request.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Taking hostname from uts namespace if not safe, because this cuold be
performind during umount operation on child reaper death. And in this case
current->nsproxy is NULL already.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NSM RPC client can be required on NFSv3 umount, when child reaper is dying (and
destroying it's mount namespace). It means, that current nsproxy is set to
NULL already, but creation of RPC client requires UTS namespace for gaining
hostname string.
This patch introduces reference counted NFS RPC clients creation and
destruction helpers (similar to RPCBIND RPC clients).
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

This patch also introduces refcount-aware nfs_callback_down_net() wrapper for
svc_shutdown_net().
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

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

Usage coutner now increased only is the service was started sccessfully.
Even if service is running already, then goto is not required anymore, because
service creation and start will be skipped.
With this patch code looks clearer.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>