After a server reboot, the reclaimer thread will recover all the existing
locks. For locks that are blocked, however, it will change the value
of block->b_status to nlm_lck_denied_grace_period in order to signal that
they need to wake up and resend the original blocking lock request.

Due to a bug, however, the block->b_status never gets reset after the
blocked locks have been woken up, and so the process goes into an
infinite loop of resends until the blocked lock is satisfied.

Reported-by: Marc Eshel <eshel@us.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

Defensive patch to ensure that we copy the state->open_stateid, which
can never be set to the delegation stateid.

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

Fix nfs4_select_rw_stateid() so that it chooses the open stateid
(or an all-zero stateid) if the delegation does not match the selected
read/write mode.

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

RFC 3530 says that the seconds value of a nfstime4 structure is a 64bit
value, but we are instead sending a 32-bit 0 and then a 32bit conversion
of the 64bit Linux value.  This means that if we try to set atime to a
value before the epoch (touch -t 196001010101) the client will only send
part of the new value due to lost precision.

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

If we're doing NFSv4.1 against a server that has persistent sessions,
then we should not need to call SETATTR in order to reset the file
attributes immediately after doing an exclusive create.

Note that since the create mode depends on the type of session that
has been negotiated with the server, we should not choose the
mode until after we've got a session slot.

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

This ensures that the RPC layer doesn't override the NFS session
negotiation.

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

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>

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>

Currently, _nfs4_do_setattr() will use the delegation stateid if no
writeable open file stateid is available.
If the server revokes that delegation stateid, then the call to
nfs4_handle_exception() will fail to handle the error due to the
lack of a struct nfs4_state, and will just convert the error into
an EIO.

This patch just removes the requirement that we must have a
struct nfs4_state in order to invalidate the delegation and
retry.

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

Otherwise we deadlock if state recovery is initiated while we
sleep.

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

The second check was added in commit 65b62a29

 but it will never be true.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

This will later allow NFS locking code to wait for readahead to complete
before releasing byte range locks.

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

When we send a RENEW or SEQUENCE operation in order to probe if the
lease is still valid, we want it to be able to time out since the
lease we are probing is likely to time out too. Currently, because
we use soft mount semantics for these RPC calls, the return value
is EIO, which causes the state manager to exit with an "unhandled
error" message.
This patch changes the call semantics, so that the RPC layer returns
ETIMEDOUT instead of EIO. We then have the state manager default to
a simple retry instead of exiting.

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

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

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

If the state manager thread is already running, we may end up
racing with it in nfs_client_return_marked_delegations. Better to
just allow the state manager thread to do the job.

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

Currently, if the application that holds the file open isn't doing
I/O, we may end up returning the delegation. This means that we can
no longer cache the file as aggressively, and often also that we
multiply the state that both the server and the client needs to track.

This patch adds a check for open files to the routine that scans
for delegations that are unreferenced.

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

Unify the error handling in nfs4_open_delegation_recall and
nfs4_lock_delegation_recall.

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

Make it symmetric with nfs4_lock_delegation_recall

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

All error cases are handled by the switch() statement, meaning that the
call to nfs4_handle_exception() is unreachable.

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

A server shouldn't normally return NFS4ERR_GRACE if the client holds a
delegation, since no conflicting lock reclaims can be granted, however
the spec does not require the server to grant the open in this
instance

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

A server shouldn't normally return NFS4ERR_GRACE if the client holds a
delegation, since no conflicting lock reclaims can be granted, however
the spec does not require the server to grant the lock in this
instance.

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

The Kconfig entry for SUNRPC_SWAP selects NETVM. That select statement
was added in commit a564b8f0

 ("nfs:
enable swap on NFS"). But there's no Kconfig symbol NETVM. It apparently
was only in used in development versions of the swap over nfs
functionality but never entered mainline. Anyhow, it is a nop and can
safely be dropped.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

The v4.1 callback thread has set_freezable() at the top, but it doesn't
ever try to freeze within the loop. Have it call try_to_freeze() at the
top of the loop. If a freeze event occurs, recheck kthread_should_stop()
after thawing.

Reported-by: Yanchuan Nian <ycnian@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

If the server sends us a pathname with more components than the client
limit of NFS4_PATHNAME_MAXCOMPONENTS, more server entries than the client
limit of NFS4_FS_LOCATION_MAXSERVERS, or sends a total number of
fs_locations entries than the client limit of NFS4_FS_LOCATIONS_MAXENTRIES
then we will currently Oops because the limit checks are done _after_ we've
decoded the data into the arrays.

Reported-by:  <fanchaoting&lt;fanchaoting@cn.fujitsu.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

If the open_context for the file is not yet fully initialised,
then open recovery cannot succeed, and since nfs4_state_find_open_context
returns an ENOENT, we end up treating the file as being irrecoverable.

What we really want to do, is just defer the recovery until later.

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

With unlink is an asynchronous operation in the sillyrename case, it
expects nfs4_async_handle_error() to map the error correctly.

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

Now that we do CLAIM_FH opens, we may run into situations where we
get a delegation but don't have perfect knowledge of the file path.
When returning the delegation, we might therefore not be able to
us CLAIM_DELEGATE_CUR opens to convert the delegation into OPEN
stateids and locks.

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

Sometimes, we actually _want_ to do open-by-filehandle, for instance
when recovering opens after a network partition, or when called
from nfs4_file_open.
Enable that functionality using a new capability NFS_CAP_ATOMIC_OPEN_V1,
and which is only enabled for NFSv4.1 servers that support it.

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

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

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

Follow the practice described in section 8.2.2 of RFC5661: When sending a
read/write or setattr stateid, set the seqid field to zero in order to
signal that the NFS server should apply the most recent locking state.

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

Clean up the setting of the nfs_server->caps, by shoving it all
into nfs4_server_common_setup().
Then add an 'initial capabilities' field into struct nfs4_minor_version_ops.

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

Adds logic to ensure that if the server returns a BAD_STATEID,
or other state related error, then we check if the stateid has
already changed. If it has, then rather than start state recovery,
we should just resend the failed RPC call with the new stateid.

Allow nfs4_select_rw_stateid to notify that the stateid is unstable by
having it return -EWOULDBLOCK if an RPC is underway that might change the
stateid.

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

If we replay a READ or WRITE call, we should not be changing the
stateid. Currently, we may end up doing so, because the stateid
is only selected at xdr encode time.

This patch ensures that we select the stateid after we get an NFSv4.1
session slot, and that we keep that same stateid across retries.

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

Currently, we're forcing an unnecessary duplication of the
initial nfs_lock_context in calls to nfs_get_lock_context, since
__nfs_find_lock_context ignores the ctx->lock_context.

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

If the state recovery failed, we want to ensure that the application
doesn't try to use the same file descriptor for more reads or writes.

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

If state recovery fails with an ESTALE or a ENOENT, then we shouldn't
keep retrying. Instead, mark the stateid as being invalid and
fail the I/O with an EIO error.
For other operations such as POSIX and BSD file locking, truncate
etc, fail with an EBADF to indicate that this file descriptor is no
longer valid.

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

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>