NFSv4 state recovery is not always successful.  Failure is signalled
by setting the nfs_client.cl_cons_state to a negative (errno) value,
then waking waiters.

Currently this can happen only during mount processing.  I'm about to
add an explicit case where state recovery failure during normal
operation should force all NFS requests waiting on that state recovery
to exit.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The gss_mech_list_pseudoflavors() function provides a list of
currently registered GSS pseudoflavors.  This list does not include
any non-GSS flavors that have been registered with the RPC client.
nfs4_find_root_sec() currently adds these extra flavors by hand.

Instead, nfs4_find_root_sec() should be looking at the set of flavors
that have been explicitly registered via rpcauth_register().  And,
other areas of code will soon need the same kind of list that
contains all flavors the kernel currently knows about (see below).

Rather than cloning the open-coded logic in nfs4_find_root_sec() to
those new places, introduce a generic RPC function that generates a
full list of registered auth flavors and pseudoflavors.

A new rpc_authops method is added that lists a flavor's
pseudoflavors, if it has any.  I encountered an interesting module
loader loop when I tried to get the RPC client to invoke
gss_mech_list_pseudoflavors() by name.

This patch is a pre-requisite for server trunking discovery, and a
pre-requisite for fixing up the in-kernel mount client to do better
automatic security flavor selection.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Squelch compiler warnings:

fs/nfs/nfs4proc.c: In function ‘__nfs4_get_acl_uncached’:
fs/nfs/nfs4proc.c:3811:14: warning: comparison between signed and
	unsigned integer expressions [-Wsign-compare]
fs/nfs/nfs4proc.c:3818:15: warning: comparison between signed and
	unsigned integer expressions [-Wsign-compare]

Introduced by commit bf118a34 "NFSv4: include bitmap in nfsv4 get
acl data", Dec 7, 2011.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

As a finishing touch, add appropriate documenting comments and some
debugging printk's.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: Instead of open-coded flag manipulation, use test_bit() and
clear_bit() just like all other accessors of the state->flag field.
This also eliminates several unnecessary implicit integer type
conversions.

To make it absolutely clear what is going on, a number of comments
are introduced.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The "state->flags & flags" test in nfs41_check_expired_stateid()
allows the state manager to squelch a TEST_STATEID operation when
it is known for sure that a state ID is no longer valid.  If the
lease was purged, for example, the client already knows that state
ID is now defunct.

But open recovery is still needed for that inode.

To force a call to nfs4_open_expired(), change the default return
value for nfs41_check_expired_stateid() to force open recovery, and
the default return value for nfs41_check_locks() to force lock
recovery, if the requested flags are clear.  Fix suggested by Bryan
Schumaker.

Also, the presence of a delegation state ID must not prevent normal
open recovery.  The delegation state ID must be cleared if it was
revoked, but once cleared I don't think it's presence or absence has
any bearing on whether open recovery is still needed.  So the logic
is adjusted to ignore the TEST_STATEID result for the delegation
state ID.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The result of a TEST_STATEID operation can indicate a few different
things:

  o If NFS_OK is returned, then the client can continue using the
    state ID under test, and skip recovery.

  o RFC 5661 says that if the state ID was revoked, then the client
    must perform an explicit FREE_STATEID before trying to re-open.

  o If the server doesn't recognize the state ID at all, then no
    FREE_STATEID is needed, and the client can immediately continue
    with open recovery.

Let's err on the side of caution: if the server clearly tells us the
state ID is unknown, we skip the FREE_STATEID.  For any other error,
we issue a FREE_STATEID.  Sometimes that FREE_STATEID will be
unnecessary, but leaving unused state IDs on the server needlessly
ties up resources.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The TEST_STATEID and FREE_STATEID operations can return
-NFS4ERR_BAD_STATEID, -NFS4ERR_OLD_STATEID, or -NFS4ERR_DEADSESSION.

nfs41_{test,free}_stateid() should not pass these errors to
nfs4_handle_exception() during state recovery, since that will
recursively kick off state recovery again, resulting in a deadlock.

In particular, when the TEST_STATEID operation returns NFS4_OK,
res.status can contain one of these errors.  _nfs41_test_stateid()
replaces NFS4_OK with the value in res.status, which is then returned
to callers.

But res.status is not passed through nfs4_stat_to_errno(), and thus is
a positive NFS4ERR value.  Currently callers are only interested in
!NFS4_OK, and nfs4_handle_exception() ignores positive values.

Thus the res.status values are currently ignored by
nfs4_handle_exception() and won't cause the deadlock above.  Thanks to
this missing negative, it is only when these operations fail (which
is very rare) that a deadlock can occur.

Bryan agrees the original intent was to return res.status as a
negative NFS4ERR value to callers of nfs41_test_stateid().
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Don't pass nfs_open_context() to ->create().  Only the NFS4 implementation
needed that and only because it wanted to return an open file using open
intents.  That task has been replaced by ->atomic_open so it is not necessary
anymore to pass the context to the create rpc operation.

Despite nfs4_proc_create apparently being okay with a NULL context it Oopses
somewhere down the call chain.  So allocate a context here.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

pNFS needs to select a write function based on the layout driver
currently in use, so I let each NFS version decide how to best handle
initializing writes.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

pNFS needs to select a read function based on the layout driver
currently in use, so I let each NFS version decide how to best handle
initializing reads.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This gives NFS v4 a way to set up callbacks and sessions without v2 or
v3 having to do them as well.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

NFS v4 needs a way to shut down callbacks and sessions, but v2 and v3
don't.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Delegations are a v4 feature, so push return_delegation out of the
generic client by creating a new rpc_op and renaming the old function to
be in the nfs v4 "namespace"
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Delegations are a v4 feature, so push them out of the generic code.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The generic client doesn't need to know about pnfs layout drivers, so
this should be done in the v4 code.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.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>

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

Commit 536e43d1 ATTR_OPEN check can result in
an ia_valid with only ATTR_FILE set, and no NFS_VALID_ATTRS attributes to
request from the server.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

While nfs4_do_open() expects the fmode argument to be restricted to
combinations of FMODE_READ and FMODE_WRITE, both nfs4_atomic_open()
and nfs4_proc_create will pass the nfs_open_context->mode,
which contains the full fmode_t.

This patch ensures that nfs4_do_open strips the other fmode_t bits,
fixing a problem in which the nfs4_do_open call would result in an
unnecessary delegation return.
Reported-by: NFred Isaman <iisaman@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

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

Sservers that only have NFSv4.1 support the
NFS4ERR_MINOR_VERS_MISMATCH error is return on
v4.0 mounts. Mapping that error to EPROTONOSUPPORT
will cause the mount to back off to v3 instead of
failing.
Signed-off-by: NSteve Dickson <steved@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There is no need to bug the user about the server returning an error
on destroy_session. The error will be handled by the state manager,
without any need for further input from anyone else.
So convert that printk into a debugging dprintk.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The open recovery code does not need to request a new value for the
mdsthreshold, and so does not allocate a struct nfs4_threshold.
The problem is that encode_getfattr_open() will still request an
mdsthreshold, and so we end up Oopsing in decode_attr_mdsthreshold.

This patch fixes encode_getfattr_open so that it doesn't request an
mdsthreshold when the caller isn't asking for one. It also fixes
decode_attr_mdsthreshold so that it errors if the server returns
an mdsthreshold that we didn't ask for (instead of Oopsing).
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Andy Adamson <andros@netapp.com>

If a file OPEN is denied due to a share lock, the resulting
NFS4ERR_SHARE_DENIED is currently mapped to the default EIO.
This patch adds a more appropriate mapping, and brings Linux
into line with what Solaris 10 does.

See https://bugzilla.kernel.org/show_bug.cgi?id=43286Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

We're already invalidating the data cache, and setting the new change
attribute. Since directories don't care about the i_size field, there
is no need to be forcing any extra revalidation of the page cache.

We do keep the NFS_INO_INVALID_ATTR flag, in order to force an
attribute cache revalidation on stat() calls since we do not
update the mtime and ctime fields.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Let nfs4_schedule_session_recovery() handle the details of choosing
between resetting the session, and other session related recovery.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the EXCHGID4_FLAG_CONFIRMED_R flag is set, the client is in theory
supposed to already know the correct value of the seqid, in which case
RFC5661 states that it should ignore the value returned.

Also ensure that if the sanity check in nfs4_check_cl_exchange_flags
fails, then we must not change the nfs_client fields.

Finally, clean up the code: we don't need to retest the value of
'status' unless it can change.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that we destroy our lease on last unmount
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

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

Exchange ID can be called in a lease reclaim situation, so it
will deadlock if it then tries to write out dirty NFS pages.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch adds the BIND_CONN_TO_SESSION operation which is needed for
upcoming SP4_MACH_CRED work and useful for recovering from broken connections
without destroying the session.
Signed-off-by: NWeston Andros Adamson <dros@netapp.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>

Ensure that a process that uses the nfs_client->cl_cons_state test
for whether the initialisation process is finished does not read
stale data.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Session initialisation is not complete until the lease manager
has run. We need to ensure that both nfs4_init_session and
nfs4_init_ds_session do so, and that they check for any resulting
errors in clp->cl_cons_state.

Only after this is done, can nfs4_ds_connect check the contents
of clp->cl_exchange_flags.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Andy Adamson <andros@netapp.com>

Save the server major and minor ID results from EXCHANGE_ID, as they
are needed for detecting server trunking.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently our NFS client assigns a unique SETCLIENTID boot verifier
for each server IP address it knows about.  It's set to CURRENT_TIME
when the struct nfs_client for that server IP is created.

During the SETCLIENTID operation, our client also presents an
nfs_client_id4 string to servers, as an identifier on which the server
can hang all of this client's NFSv4 state.  Our client's
nfs_client_id4 string is unique for each server IP address.

An NFSv4 server is obligated to wipe all NFSv4 state associated with
an nfs_client_id4 string when the client presents the same
nfs_client_id4 string along with a changed SETCLIENTID boot verifier.

When our client unmounts the last of a server's shares, it destroys
that server's struct nfs_client.  The next time the client mounts that
NFS server, it creates a fresh struct nfs_client with a fresh boot
verifier.  On seeing the fresh verifer, the server wipes any previous
NFSv4 state associated with that nfs_client_id4.

However, NFSv4.1 clients are supposed to present the same
nfs_client_id4 string to all servers.  And, to support Transparent
State Migration, the same nfs_client_id4 string should be presented
to all NFSv4.0 servers so they recognize that migrated state for this
client belongs with state a server may already have for this client.
(This is known as the Uniform Client String model).

If the nfs_client_id4 string is the same but the boot verifier changes
for each server IP address, SETCLIENTID and EXCHANGE_ID operations
from such a client could unintentionally result in a server wiping a
client's previously obtained lease.

Thus, if our NFS client is going to use a fixed nfs_client_id4 string,
either for NFSv4.0 or NFSv4.1 mounts, our NFS client should use a
boot verifier that does not change depending on server IP address.
Replace our current per-nfs_client boot verifier with a per-nfs_net
boot verifier.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

nfs4_reset_all_state() refreshes the boot verifier a server sees to
trigger that server to wipe this client's state.  This function is
invoked when an NFSv4.1 server reports that it has revoked some or
all of a client's NFSv4 state.

To facilitate server trunking discovery, we will eventually want to
move the cl_boot_time field to a more global structure.  The Uniform
Client String model (and specifically, server trunking detection)
requires that all servers see the same boot verifier until the client
actually does reboot, and not a fresh verifier every time the client
unmounts and remounts the server.

Without the cl_boot_time field, however, nfs4_reset_all_state() will
have to find some other way to force the server to purge the client's
NFSv4 state.

Because these verifiers are opaque (ie, the server doesn't know or
care that they happen to be timestamps), we can force the server
to wipe NFSv4 state by updating the boot verifier as we do now, then
immediately afterwards establish a fresh client ID using the old boot
verifier again.

Hopefully there are no extra paranoid server implementations that keep
track of the client's boot verifiers and prevent clients from reusing
a previous one.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: update to use matching types in "if" expressions.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>