NFS: NFSoRDMA Client Side Changes

New Features:
- Support for SG_GAP devices

Bugfixes and cleanups:
- Cap size of callback buffer resources
- Improve send queue and RPC metric accounting
- Fix coverity warning
- Avoid calls to ro_unmap_safe()
- Refactor FRMR invalidation
- Error message improvements

There are two problems with refcounting of auth_gss messages.

First, the reference on the pipe->pipe list (taken by a call
to rpc_queue_upcall()) is not counted.  It seems to be
assumed that a message in pipe->pipe will always also be in
pipe->in_downcall, where it is correctly reference counted.

However there is no guaranty of this.  I have a report of a
NULL dereferences in rpc_pipe_read() which suggests a msg
that has been freed is still on the pipe->pipe list.

One way I imagine this might happen is:
- message is queued for uid=U and auth->service=S1
- rpc.gssd reads this message and starts processing.
  This removes the message from pipe->pipe
- message is queued for uid=U and auth->service=S2
- rpc.gssd replies to the first message. gss_pipe_downcall()
  calls __gss_find_upcall(pipe, U, NULL) and it finds the
  *second* message, as new messages are placed at the head
  of ->in_downcall, and the service type is not checked.
- This second message is removed from ->in_downcall and freed
  by gss_release_msg() (even though it is still on pipe->pipe)
- rpc.gssd tries to read another message, and dereferences a pointer
  to this message that has just been freed.

I fix this by incrementing the reference count before calling
rpc_queue_upcall(), and decrementing it if that fails, or normally in
gss_pipe_destroy_msg().

It seems strange that the reply doesn't target the message more
precisely, but I don't know all the details.  In any case, I think the
reference counting irregularity became a measureable bug when the
extra arg was added to __gss_find_upcall(), hence the Fixes: line
below.

The second problem is that if rpc_queue_upcall() fails, the new
message is not freed. gss_alloc_msg() set the ->count to 1,
gss_add_msg() increments this to 2, gss_unhash_msg() decrements to 1,
then the pointer is discarded so the memory never gets freed.

Fixes: 9130b8db ("SUNRPC: allow for upcalls for same uid but different gss service")
Cc: stable@vger.kernel.org
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1011250Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Clients can set the umask attribute when creating files to cause the
server to apply it always except when inheriting permissions from the
parent directory.  That way, the new files will end up with the same
permissions as files created locally.

See https://tools.ietf.org/html/draft-ietf-nfsv4-umask-02 for more details.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The flexfiles client can piggyback both layout errors and layoutstats
as part of the layoutreturn. Both these payloads can get large, with
20 layout error entries taking up about 1.2K, and 4 layoutstats entries
taking up another 1K.
This patch allows a maximum payload of 4k by allocating a full page.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

  We encountered a deadlock where the SEQUENCE that accompanied the
LAYOUTGET triggered a session drain, while ff_layout_alloc_lseg
triggered a GETDEVICEINFO.  The GETDEVICEINFO hung waiting for the
session drain, while the LAYOUTGET held the slot waiting for
alloc_lseg to finish.
  Avoid this by moving the call to nfs4_find_get_deviceid out of
ff_layout_alloc_lseg and into nfs4_ff_layout_prepare_ds.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
[dros@primarydata.com: pNFS/flexfiles: fix races in ff_layout_mirror_valid]
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The layout-private data may depend on the layout and/or the inode
still existing when it does post-processing and frees its data, so we
need to free them after calling lrp->ld_private.ops->free().

This fixes a mirror list corruption issue in the flexfiles driver.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

When we're merging an old entry into our new entry, we want to ensure that
we add the list entry in the correct place.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Otherwise the lock context won't be freed when we're done with it.

From: NeilBrown <neilb@suse.com>
Fixes: 5bd3f817 ("NFSv4: change nfs4_select_rw_stateid to take a lock_context inplace of lock_owner")
Signed-off-by: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Ensure we release the NFS_LAYOUT_RETURN lock when we invalidate the
layout stateid, so that processes and RPC tasks that are waiting on
the layout return can continue.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If the session has an error, then we want to start by recovering the
session, as any SEQUENCE we send is going to fail with a session
error.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

In the case where SEQUENCE receives a NFS4ERR_BADSESSION or
NFS4ERR_DEADSESSION error, we just want to report the session as needing
recovery, and then we want to retry the operation.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

When looking at whether or not our dcache is valid, we really don't care
about the general state of the directory attribute cache. Instead, we
we only care about the state of the change attribute.

This fixes a performance issue when the client is responsible for
changing the directory contents; a number of NFSv4 operations will
atomically update the directory change attribute, but may not return
all the other attributes.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We should only care about checking the attributes if the page cache
is marked as dubious (using NFS_INO_REVAL_PAGECACHE) and the
NFS_INO_REVAL_FORCED flag is set.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We should only care about checking the attributes if the page cache
is marked as dubious (using NFS_INO_REVAL_PAGECACHE) and the
NFS_INO_REVAL_FORCED flag is set.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Add the ability to send an array of layoutstats entries as part of
layoutreturn.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Need to lock while reading in order to ensure 64-bit reads are correct.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Add the layout error payload to the flexfiles layoutreturn private
data, and set up the encoding mechanisms. This is a refactoring in
preparation for adding the layout iostats payload.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Add a callback to allow the flexfiles layout driver to initialise the
layout private payload.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Cleanup to allow layout drivers to attach private data to layoutreturn,
and manage the data.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If there have been no reads or writes to a given mirror since the last
layoutstats update, then don't resend the same data.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If the list of mirrors is empty, then don't send an RPC call.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If the use called stat() on an 'ls -l' workload, and the attribute
cache was successfully revalidate by READDIRPLUS, then we want to
report that back so that the readdir code continues to use
readdirplus.
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

There is little point in setting NFS_INO_ADVISE_RDPLUS in nfs_lookup and
nfs_lookup_revalidate() unless a process is actually doing readdir on the
parent directory.
Furthermore, there is little point in using readdirplus if we're trying
to revalidate a negative dentry.
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Ben Coddington reports that commit 311324ad, by adding the function
nfs_dir_mapping_need_revalidate() that checks page cache validity on
each call to nfs_readdir() causes a performance regression when
the directory is being modified.

If the directory is changing while we're iterating through the directory,
POSIX does not require us to invalidate the page cache unless the user
calls rewinddir(). However, we still do want to ensure that we use
readdirplus in order to avoid a load of stat() calls when the user
is doing an 'ls -l' workload.

The fix should be to invalidate the page cache immediately when we're
setting the NFS_INO_ADVISE_RDPLUS bit.
Reported-by: Benjamin Coddington <bcodding@redhat.com>
Fixes: 311324ad ("NFS: Be more aggressive in using readdirplus...")
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Fix typo in parameter description.

Fixes: 5405fc44 ("NFSv4.x: Add kernel parameter to control the
callback server")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

It now has only one field and is only used in one structure.
So replaced it in that structure by the field it contains.
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

A process can have two possible lock owner for a given open file:
a per-process Posix lock owner and a per-open-file flock owner
Use both of these when searching for a suitable stateid to use.

With this patch, READ/WRITE requests will use the correct stateid
if a flock lock is active.
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The only time that a lock_context is not immediately available is in
setattr, and now that it has an open_context, it can easily find one
with nfs_get_lock_context.
This removes the need for the on-stack nfs_lockowner.

This change is preparation for correctly support flock stateids.
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The open_context can always lead directly to the state, and is always easily
available, so this is a straightforward change.
Doing this makes more information available to _nfs4_do_setattr() for use
in the next patch.
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

An open file description (struct file) in a given process can be
associated with two different lock owners.

It can have a Posix lock owner which will be different in each process
that has a fd on the file.
It can have a Flock owner which will be the same in all processes.

When searching for a lock stateid to use, we need to consider both of these
owners

So add a new "flock_owner" to the "nfs_open_context" (of which there
is one for each open file description).

This flock_owner does not need to be reference-counted as there is a
1-1 relation between 'struct file' and nfs open contexts,
and it will never be part of a list of contexts.  So there is no need
for a 'flock_context' - just the owner is enough.

The io_count included in the (Posix) lock_context provides no
guarantee that all read-aheads that could use the state have
completed, so not supporting it for flock locks in not a serious
problem.  Synchronization between flock and read-ahead can be added
later if needed.

When creating an open_context for a non-openning create call, we don't have
a 'struct file' to pass in, so the lock context gets initialized with
a NULL owner, but this will never be used.

The flock_owner is not used at all in this patch, that will come later.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

this field is not used in any important way and probably should
have been removed by

Commit: 8003d3c4 ("nfs4: treat lock owners as opaque values")

which removed the pid argument from nfs4_get_lock_state.

Except in unusual and uninteresting cases, two threads with the same
->tgid will have the same ->files pointer, so keeping them both
for comparison brings no benefit.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

This parameter hasn't been used since 2a009ec9 (Linux 3.13-rc3), so
let's remove it from this function.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

This parameter hasn't been used since f8407299 (Linux 3.11-rc2), so
let's remove it from this function and callers.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

It's possible that two different servers can return the same (clientid,
verifier) pair purely by coincidence.  Both are 64-bit values, but
depending on the server implementation, they can be highly predictable
and collisions may be quite likely, especially when there are lots of
servers.

So, check for this case.  If the clientid and verifier both match, then
we actually know they *can't* be the same server, since a new
SETCLIENTID to an already-known server should have changed the verifier.

This helps fix a bug that could cause the client to mount a filesystem
from the wrong server.
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Tested-by: Yongcheng Yang <yoyang@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

xs_connect() contains an exponential backoff mechanism so the repeated
connection attempts are delayed by longer and longer amounts.

This is appropriate when the connection failed due to a timeout, but
it not appropriate when a definitive "no" answer is received.  In such
cases, call_connect_status() imposes a minimum 3-second back-off, so
not having the exponetial back-off will never result in immediate
retries.

The current situation is a problem when the NFS server tries to
register with rpcbind but rpcbind isn't running.  All connection
attempts are made on the same "xprt" and as the connection is never
"closed", the exponential back delays successive attempts to register,
or de-register, different protocols.  This results in a multi-minute
delay with no benefit.

So, when call_connect_status() receives a definitive "no", use
xprt_conditional_disconnect() to cancel the previous connection attempt.
This will set XPRT_CLOSE_WAIT so that xprt->ops->close() calls xs_close()
which resets the reestablish_timeout.

To ensure xprt_conditional_disconnect() does the right thing, we
ensure that rq_connect_cookie is set before a connection attempt, and
allow xprt_conditional_disconnect() to complete even when the
transport is not fully connected.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If the layout stateid is already invalid, we have no work to do.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>