If write_ports_addfd or write_ports_addxprt fail, they call nfsd_put()
without calling nfsd_last_thread().  This leaves nn->nfsd_serv pointing
to a structure that has been freed.

So remove 'static' from nfsd_last_thread() and call it when the
nfsd_serv is about to be destroyed.

Fixes: ec52361d ("SUNRPC: stop using ->sv_nrthreads as a refcount")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Introduce rpc_status netlink support for NFSD in order to dump pending
RPC requests debugging information from userspace.

Closes: https://bugzilla.linux-nfs.org/show_bug.cgi?id=366


Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Now that the last nfsd thread is stopped by an explicit act of calling
svc_set_num_threads() with a count of zero, we only have a limited
number of places that can happen, and don't need to call
nfsd_last_thread() in nfsd_put()

So separate that out and call it at the two places where the number of
threads is set to zero.

Move the clearing of ->nfsd_serv and the call to svc_xprt_destroy_all()
into nfsd_last_thread(), as they are really part of the same action.

nfsd_put() is now a thin wrapper around svc_put(), so make it a static
inline.

nfsd_put() cannot be called after nfsd_last_thread(), so in a couple of
places we have to use svc_put() instead.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Currently, svcauth_gss_accept() pre-reserves response buffer space
for the RPC payload length and GSS sequence number before returning
to the dispatcher, which then adds the header's accept_stat field.

The problem is the accept_stat field is supposed to go before the
length and seq_num fields. So svcauth_gss_release() has to relocate
the accept_stat value (see svcauth_gss_prepare_to_wrap()).

To enable these fields to be added to the response buffer in the
correct (final) order, the pointer to the accept_stat has to be made
available to svcauth_gss_accept() so that it can set it before
reserving space for the length and seq_num fields.

As a first step, move the pointer to the location of the accept_stat
field into struct svc_rqst.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Currently the nfsd-client shrinker is registered and unregistered at
the time the nfsd module is loaded and unloaded. The problem with this
is the shrinker is being registered before all of the relevant fields
in nfsd_net are initialized when nfsd is started. This can lead to an
oops when memory is low and the shrinker is called while nfsd is not
running.

This patch moves the  register/unregister of nfsd-client shrinker from
module load/unload time to nfsd startup/shutdown time.

Fixes: 44df6f43 ("NFSD: add delegation reaper to react to low memory condition")
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

rpc.nfsd stopped supporting NFSv2 a year ago. Take the next logical
step toward deprecating it and allow NFSv2 support to be compiled out.

Add a new CONFIG_NFSD_V2 option that can be turned off and rework the
CONFIG_NFSD_V?_ACL option dependencies. Add a description that
discourages enabling it.

Also, change the description of CONFIG_NFSD to state that the always-on
version is now 3 instead of 2.

Finally, add an #ifdef around "case 2:" in __write_versions. When NFSv2
is disabled at compile time, this should make the kernel ignore attempts
to disable it at runtime, but still error out when trying to enable it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Add courtesy_client_reaper to react to low memory condition triggered
by the system memory shrinker.

The delayed_work for the courtesy_client_reaper is scheduled on
the shrinker's count callback using the laundry_wq.

The shrinker's scan callback is not used for expiring the courtesy
clients due to potential deadlocks.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Subsequent patches will use this mechanism to wake up an operation
that is waiting for a client to return a delegation.

The new tracepoint records whether the wait timed out or was
properly awoken by the expected DELEGRETURN:

            nfsd-1155  [002] 83799.493199: nfsd_delegret_wakeup: xid=0x14b7d6ef fh_hash=0xf6826792 (timed out)

Suggested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>

Currently there is no limit on how many v4 clients are supported
by the system. This can be a problem in systems with small memory
configuration to function properly when a very large number of
clients exist that creates memory shortage conditions.

This patch enforces a limit of 1024 NFSv4 clients, including courtesy
clients, per 1GB of system memory.  When the number of the clients
reaches the limit, requests that create new clients are returned
with NFS4ERR_DELAY and the laundromat is kicked start to trim old
clients. Due to the overhead of the upcall to remove the client
record, the maximun number of clients the laundromat removes on
each run is limited to 128. This is done to ensure the laundromat
can still process the other tasks in a timely manner.

Since there is now a limit of the number of clients, the 24-hr
idle time limit of courtesy client is no longer needed and was
removed.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This patch moves the v4 specific code from nfsd_init_net() to
nfsd4_init_leases_net() helper in nfs4state.c

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

NFSD has advertised support for the NFSv4 time_create attribute
since commit e377a3e6 ("nfsd: Add support for the birth time
attribute").

Igor Mammedov reports that Mac OS clients attempt to set the NFSv4
birth time attribute via OPEN(CREATE) and SETATTR if the server
indicates that it supports it, but since the above commit was
merged, those attempts now fail.

Table 5 in RFC 8881 lists the time_create attribute as one that can
be both set and retrieved, but the above commit did not add server
support for clients to provide a time_create attribute. IMO that's
a bug in our implementation of the NFSv4 protocol, which this commit
addresses.

Whether NFSD silently ignores the new birth time or actually sets it
is another matter. I haven't found another filesystem service in the
Linux kernel that enables users or clients to modify a file's birth
time attribute.

This commit reflects my (perhaps incorrect) understanding of whether
Linux users can set a file's birth time. NFSD will now recognize a
time_create attribute but it ignores its value. It clears the
time_create bit in the returned attribute bitmask to indicate that
the value was not used.

Reported-by: Igor Mammedov <imammedo@redhat.com>
Fixes: e377a3e6 ("nfsd: Add support for the birth time attribute")
Tested-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This patch moves create/destroy of laundry_wq from nfs4_state_start
and nfs4_state_shutdown_net to init_nfsd and exit_nfsd to prevent
the laundromat from being freed while a thread is processing a
conflicting lock.

Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This patch provides courteous server support for delegation only.
Only expired client with delegation but no conflict and no open
or lock state is allowed to be in COURTESY state.

Delegation conflict with COURTESY/EXPIRABLE client is resolved by
setting it to EXPIRABLE, queue work for the laundromat and return
delay to the caller. Conflict is resolved when the laudromat runs
and expires the EXIRABLE client while the NFS client retries the
OPEN request. Local thread request that gets conflict is doing the
retry in _break_lease.

Client in COURTESY or EXPIRABLE state is allowed to reconnect and
continues to have access to its state. Access to the nfs4_client by
the reconnecting thread and the laundromat is serialized via the
client_lock.

Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

For filesystems that supports "btime" timestamp (i.e. most modern
filesystems do) we share it via kernel nfsd. Btime support for NFS
client has already been added by Trond recently.

Suggested-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Ondrej Valousek <ondrej.valousek.xm@renesas.com>
[ cel: addressed some whitespace/checkpatch nits ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

svc_destroy() is poorly named - it doesn't necessarily destroy the svc,
it might just reduce the ref count.
nfsd_destroy() is poorly named for the same reason.

This patch:
 - removes the refcount functionality from svc_destroy(), moving it to
   a new svc_put().  Almost all previous callers of svc_destroy() now
   call svc_put().
 - renames nfsd_destroy() to nfsd_put() and improves the code, using
   the new svc_destroy() rather than svc_put()
 - removes a few comments that explain the important for balanced
   get/put calls.  This should be obvious.

The only non-trivial part of this is that svc_destroy() would call
svc_sock_update() on a non-final decrement.  It can no longer do that,
and svc_put() isn't really a good place of it.  This call is now made
from svc_exit_thread() which seems like a good place.  This makes the
call *before* sv_nrthreads is decremented rather than after.  This
is not particularly important as the call just sets a flag which
causes sv_nrthreads set be checked later.  A subsequent patch will
improve the ordering.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Returning an undecorated integer is an age-old trope, but it's
not clear (even to previous experts in this code) that the only
valid return values are 1 and 0. These functions do not return
a negative errno, rpc_stat value, or a positive length.

Document there are only two valid return values by having
.pc_encode return only true or false.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The passed-in value of the "__be32 *p" parameter is now unused in
every server-side XDR encoder, and can be removed.

Note also that there is a line in each encoder that sets up a local
pointer to a struct xdr_stream. Passing that pointer from the
dispatcher instead saves one line per encoder function.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Returning an undecorated integer is an age-old trope, but it's
not clear (even to previous experts in this code) that the only
valid return values are 1 and 0. These functions do not return
a negative errno, rpc_stat value, or a positive length.

Document there are only two valid return values by having
.pc_decode return only true or false.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The passed-in value of the "__be32 *p" parameter is now unused in
every server-side XDR decoder, and can be removed.

Note also that there is a line in each decoder that sets up a local
pointer to a struct xdr_stream. Passing that pointer from the
dispatcher instead saves one line per decoder function.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Currently the source's export is mounted and unmounted on every
inter-server copy operation. This patch is an enhancement to delay
the unmount of the source export for a certain period of time to
eliminate the mount and unmount overhead on subsequent copy operations.

After a copy operation completes, a work entry is added to the
delayed unmount list with an expiration time. This list is serviced
by the laundromat thread to unmount the export of the expired entries.
Each time the export is being used again, its expiration time is
extended and the entry is re-inserted to the tail of the list.

The unmount task and the mount operation of the copy request are
synced to make sure the export is not unmounted while it's being
used.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

mountd can now monitor clients appearing and disappearing in
/proc/fs/nfsd/clients, and will log these events, in liu of the logging
of mount/unmount events for NFSv3.

Currently it cannot distinguish between unconfirmed clients (which might
be transient and totally uninteresting) and confirmed clients.

So add a "status: " line which reports either "confirmed" or
"unconfirmed", and use fsnotify to report that the info file
has been modified.

This requires a bit of infrastructure to keep the dentry for the "info"
file.  There is no need to take a counted reference as the dentry must
remain around until the client is removed.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

In order to ensure that knfsd threads don't linger once the nfsd
pseudofs is unmounted (e.g. when the container is killed) we let
nfsd_umount() shut down those threads and wait for them to exit.

This also should ensure that we don't need to do a kernel mount of
the pseudofs, since the thread lifetime is now limited by the
lifetime of the filesystem.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Collect some nfsd stats per export in addition to the global stats.

A new nfsdfs export_stats file is created.  It uses the same ops as the
exports file to iterate the export entries and we use the file's name to
determine the reported info per export.  For example:

 $ cat /proc/fs/nfsd/export_stats
 # Version 1.1
 # Path Client Start-time
 #	Stats
 /test	localhost	92
	fh_stale: 0
	io_read: 9
	io_write: 1

Every export entry reports the start time when stats collection
started, so stats collecting scripts can know if stats where reset
between samples.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This reverts commit a8585763.

We're still factoring ctime into our change attribute even in the
IS_I_VERSION case.  If someone sets the system time backwards, a client
could see the change attribute go backwards.  Maybe we can just say
"well, don't do that", but there's some question whether that's good
enough, or whether we need a better guarantee.

Also, the client still isn't actually using the attribute.

While we're still figuring this out, let's just stop returning this
attribute.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Start off the conversion to xdr_stream by de-duplicating the functions
that decode void arguments and encode void results.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Add defines for server-side extended attribute support. Most have
already been added as part of client support, but these are
the network order error codes for the noxattr and xattr2big errors,
and the addition of the xattr support to the supported file
attributes (if configured).

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

We don't drop the reference on the nfsdfs filesystem with
mntput(nn->nfsd_mnt) until nfsd_exit_net(), but that won't be called
until the nfsd module's unloaded, and we can't unload the module as long
as there's a reference on nfsdfs.  So this prevents module unloading.

Fixes: 2c830dd7 ("nfsd: persist nfsd filesystem across mounts")
Reported-and-Tested-by: Luo Xiaogang <lxgrxd@163.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

We currently revoke read delegations on any write open or any operation
that modifies file data or metadata (including rename, link, and
unlink).  But if the delegation in question is the only read delegation
and is held by the client performing the operation, that's not really
necessary.

It's not always possible to prevent this in the NFSv4.0 case, because
there's not always a way to determine which client an NFSv4.0 delegation
came from.  (In theory we could try to guess this from the transport
layer, e.g., by assuming all traffic on a given TCP connection comes
from the same client.  But that's not really correct.)

In the NFSv4.1 case the session layer always tells us the client.

This patch should remove such self-conflicts in all cases where we can
reliably determine the client from the compound.

To do that we need to track "who" is performing a given (possibly
lease-breaking) file operation.  We're doing that by storing the
information in the svc_rqst and using kthread_data() to map the current
task back to a svc_rqst.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The function was removed a long time ago, but the declaration
and a dummy implementation are still there, referencing the
deprecated time_t type.

Remove both.

Fixes: f958a132 ("nfsd4: remove unnecessary lease-setting function")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Fix __be32 and u32 mismatch in return and assignment.

Reported-by: kbuild test robot <lkp@intel.com>
Fixes: dbd4c2dd8f13 ("NFSD add COPY_NOTIFY operation")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

nfs.4 defines nfs42_netaddr structure that represents netloc4.

Populate needed fields from the sockaddr structure.

This will be used by flexfiles and 4.2 inter copy

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>

vfs_rmdir and vfs_unlink can return -EBUSY if the
target is a mountpoint.  This currently gets passed to
nfserrno() by nfsd_unlink(), and that results in a WARNing,
which is not user-friendly.

Possibly the best NFSv4 error is NFS4ERR_FILE_OPEN, because
there is a sense in which the object is currently in use
by some other task.  The Linux NFSv4 client will map this
back to EBUSY, which is an added benefit.

For NFSv3, the best we can do is probably NFS3ERR_ACCES, which isn't
true, but is not less true than the other options.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Add a new nfsd/clients/#/info file with some basic information about
each NFSv4 client.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

I plan to expose some information about nfsv4 clients here.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Convert knfsd to use the user namespace of the container that started
the server processes.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

In order to be able to interpret uids and gids correctly in knfsd, we
should cache the user namespace of the process that created the RPC
server's listener. To do so, we refcount the credential of that process.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Support use of the --nfs-version/--no-nfs-version arguments to rpc.nfsd
in containers.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The change attribute is what is used by clients to revalidate their
caches.  Our server may use i_version or ctime for that purpose.  Those
choices behave slightly differently, and it may be useful to the client
to know which we're using.  This attribute tells the client that.  The
Linux client doesn't yet use this attribute yet, though.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>