Benny points out that zero-padding of multiword bitfields is necessary,
and that delimiting each word is nice to avoid endianess confusion.

bhalevy: without zero padding output can be ambiguous. Also,
since the printed array of two 32-bit unsigned integers is not a
64-bit number, delimiting the output with a semicolon makes more sense.
Signed-off-by: NFred Isaman <iisaman@citi.umich.edu>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

All use sites for nfs{,4}_stat_to_errno negate their return value.
It's more efficient to return a negative error from the stat_to_errno convertors
rather than negating its return value everywhere. This also produces slightly
smaller code.
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Now that we've added the 'generic' credentials (that are independent of the
rpc_client) to the nfs_open_context, we can use those in the NLM client to
ensure that the lock/unlock requests are authenticated to whoever
originally opened the file.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Both NLM and NFSv4 should be able to clean up adequately in the case where
the user interrupts the RPC call...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We shouldn't remove the lock from the list of blocked locks until the
CANCEL call has completed since we may be racing with a GRANTED callback.

Also ensure that we send an UNLOCK if the CANCEL request failed. Normally
that should only happen if the process gets hit with a fatal signal.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, it returns success as long as the RPC call was sent. We'd like
to know if the CANCEL operation succeeded on the server.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The signal masks have been rendered obsolete by the preceding patch.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Peter Staubach comments:

> In the course of investigating testing failures in the locking phase of
> the Connectathon testsuite, I discovered a couple of things.  One was
> that one of the tests in the locking tests was racy when it didn't seem
> to need to be and two, that the NFS client asynchronously releases locks
> when a process is exiting.
...
> The Single UNIX Specification Version 3 specifies that:  "All locks
> associated with a file for a given process shall be removed when a file
> descriptor for that file is closed by that process or the process holding
> that file descriptor terminates.".
>
> This does not specify whether those locks must be released prior to the
> completion of the exit processing for the process or not.  However,
> general assumptions seem to be that those locks will be released.  This
> leads to more deterministic behavior under normal circumstances.

The following patch converts the NFSv2/v3 locking code to use the same
mechanism as NFSv4 for sending asynchronous RPC calls and then waiting for
them to complete. This ensures that the UNLOCK and CANCEL RPC calls will
complete even if the user interrupts the call, yet satisfies the
above request for synchronous behaviour on process exit.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When we replace the existing synchronous RPC calls with asynchronous calls,
the reference count will be needed in order to allow us to examine the
result of the RPC call.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

Also fix up nlmclnt_lock() so that it doesn't pass modified versions of
fl->fl_flags to nlmclnt_cancel() and other helpers.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It is quite possible that the OPEN, CLOSE, LOCK, LOCKU,... compounds fail
before the actual stateful operation has been executed (for instance in the
PUTFH call). There is no way to tell from the overall status result which
operations were executed from the COMPOUND.

The fix is to move incrementing of the sequence id into the XDR layer,
so that we do it as we process the results from the stateful operation.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There should be no need to invalidate a perfectly good state owner just
because of a stale filehandle. Doing so can cause the state recovery code
to break, since nfs4_get_renew_cred() and nfs4_get_setclientid_cred() rely
on finding active state owners.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

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

In the case of readpage() we need to ensure that the pages get unlocked,
and that the error is flagged.

In the case of O_DIRECT, we need to ensure that the pages are all released.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It is possible for nfs_wb_page() to sometimes exit with 0 return value, yet
the page is left in a dirty state.
For instance in the case where the server rebooted, and the COMMIT request
failed, then all the previously "clean" pages which were cached by the
server, but were not guaranteed to have been writted out to disk,
have to be redirtied and resent to the server.
The fix is to have nfs_wb_page_priority() check that the page is clean
before it exits...

This fixes a condition that triggers the BUG_ON(PagePrivate(page)) in
nfs_create_request() when we're in the nfs_readpage() path.

Also eliminate a redundant BUG_ON(!PageLocked(page)) while we're at it. It
turns out that clear_page_dirty_for_io() has the exact same test.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: refactor the encoding of the opaque 16-byte private argument in
xdr_encode_mon().  This will be updated later to support IPv6 addresses.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Switch to using the new mon_id encoder function.

Now that we've refactored the encoding of SM_MON requests, we've
discovered that the pre-computed buffer length maximums are
incorrect!
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: document the argument type that xdr_encode_common() is
marshalling by introducing a new function.  The new function will replace
xdr_encode_common() in just a sec.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: introduce a new XDR encoder specifically for the my_id
argument of SM_MON requests.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: introduce a new XDR encoder specifically for the mon_name
argument of SM_MON requests.  This will be updated later to support IPv6
addresses in addition to IPv4 addresses.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Introduce a special helper function to check the length of NSM strings
before they are placed on the wire.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: RPC protocol version numbers are u32.  Make sure we use an
appropriate type for NLM version numbers when calling nlm_lookup_host().

Eliminates a harmless mixed sign comparison in nlm_host_lookup().
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Bruce Fields says:
"By the way, we've got another config-related nit here:

	http://bugzilla.linux-nfs.org/show_bug.cgi?id=156

You can build lockd without CONFIG_SYSCTL set, but then the module will
fail to load."

For now, disable the sysctl registration calls in lockd if CONFIG_SYSCTL
is not enabled.  This allows the kernel to build properly if PROC_FS or
SYSCTL is not enabled, but an NFS client is desired.

In the long run, we would like to be able to build the kernel with an
NFS client but without lockd.  This makes sense, for example, if you want
an NFSv4-only NFS client, as NFSv4 doesn't use NLM at all.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Most distros will want support for rpcbind protocols 3 and 4 to default off
until they have integrated user-space support for the new rpcbind daemon
which supports IPv6 RPC services.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: refresh the help text for Kconfig items related to the sunrpc
module.  Remove obsolete URLs, and make the language consistent among
the options.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Since O_DIRECT is a standard feature that is enabled in most distros,
eliminate the CONFIG_NFS_DIRECTIO build option, and change the
fs/nfs/Makefile to always build in the NFS direct I/O engine.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Display all mount options in /proc/mount which may be needed to reconstruct
a previous mount.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Save the value of the mountproto= mountport= mountvers= and mountaddr=
options so that these values can be displayed later via
nfs_show_options().

This preserves the intent of the original mount options, should the file
system need to be remounted based on what's displayed in /proc/mounts.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

During a remount based on the mount options displayed in /proc/mounts, we
want to preserve the original behavior of the mount request.  Let's save
the original setting of the "port=" mount option in the mount's nfs_server
structure.

This allows us to simplify the default behavior of port setting for NFSv4
mounts: by default, NFSv2/3 mounts first try an RPC bind to determine the
NFS server's port, unless the user specified the "port=" mount option;
Users can force the client to skip the RPC bind by explicitly specifying
"port=<value>".

NFSv4, by contrast, assumes the NFS server port is 2049 and skips the RPC
bind, unless the user specifies "port=".  Users can force an RPC bind for
NFSv4 by explicitly specifying "port=0".

I added a couple of extra comments to clarify this behavior.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: make data types of fields in nfs_parsed_mount_options more
consistent with other uses.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: use %u instead of %d when displaying NFS mount options.

Nit: Fix reporting of "namlen=" option in nfs_show_mount_stats.  The mount
option is called "namlen" without the "e".
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, the NFS readdir decoders have a workaround for buggy servers
that send an empty readdir response with the EOF bit unset. If the
server sends a malformed response in some cases, this workaround kicks
in and just returns an empty response rather than returning a proper
error to the caller.

This patch does 3 things:

1) have malformed responses with no entries return error (-EIO)

2) preserve existing workaround for servers that send empty
   responses with the EOF marker unset.

3) Add some comments to clarify the logic in decode_readdir().
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, the NFS readdir decoders have a workaround for buggy servers
that send an empty readdir response with the EOF bit unset. If the
server sends a malformed response in some cases, this workaround kicks
in and just returns an empty response rather than returning a proper
error to the caller.

This patch does 3 things:

1) have malformed responses with no entries return error (-EIO)

2) preserve existing workaround for servers that send empty
   responses with the EOF marker unset.

3) Add some comments to clarify the logic in nfs3_xdr_readdirres().
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, the NFS readdir decoders have a workaround for buggy servers
that send an empty readdir response with the EOF bit unset. If the
server sends a malformed response in some cases, this workaround kicks
in and just returns an empty response rather than returning a proper
error to the caller.

This patch does 3 things:

1) have malformed responses with no entries return error (-EIO)

2) preserve existing workaround for servers that send empty
   responses with the EOF marker unset.

3) Add some comments to clarify the logic in nfs_xdr_readdirres().
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NFred Isaman <iisaman@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Both flush functions have the same error handling routine.  Pull
it out as a function.
Signed-off-by: NFred Isaman <iisaman@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ignoring the return value from nfs_pageio_add_request can cause deadlocks.

In read path:
  call nfs_pageio_add_request from readpage_async_filler
  assume at this point that there are requests already in desc, that
    can't be merged with the current request.
  so nfs_pageio_doio is fired up to clear out desc.
  assume something goes wrong in setting up the io, so desc->pg_error is set.
  This causes nfs_pageio_add_request to return 0, *WITHOUT* adding the original
    request.
  BUT, since return code is ignored, readpage_async_filler assumes it has
    been added, and does nothing further, leaving page locked.
  do_generic_mapping_read will eventually call lock_page, resulting in deadlock

In write path:
  page is marked dirty by generic_perform_write
  nfs_writepages is called
  call nfs_pageio_add_request from nfs_page_async_flush
  assume at this point that there are requests already in desc, that
    can't be merged with the current request.
  so nfs_pageio_doio is fired up to clear out desc.
  assume something goes wrong in setting up the io, so desc->pg_error is set.
  This causes nfs_page_async_flush to return 0, *WITHOUT* adding the original
    request, yet marking the request as locked (PG_BUSY) and in writeback,
    clearing dirty marks.
  The next time a write is done to the page, deadlock will result as
    nfs_write_end calls nfs_update_request
Signed-off-by: NFred Isaman <iisaman@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>