Add /proc/fs/nfsd/pool_stats to export to userspace various
statistics about the operation of rpc server thread pools.

This patch is based on a forward-ported version of
knfsd-add-pool-thread-stats which has been shipping in the SGI
"Enhanced NFS" product since 2006 and which was previously
posted:

http://article.gmane.org/gmane.linux.nfs/10375

It has also been updated thus:

 * moved EXPORT_SYMBOL() to near the function it exports
 * made the new struct struct seq_operations const
 * used SEQ_START_TOKEN instead of ((void *)1)
 * merged fix from SGI PV 990526 "sunrpc: use dprintk instead of
   printk in svc_pool_stats_*()" by Harshula Jayasuriya.
 * merged fix from SGI PV 964001 "Crash reading pool_stats before
   nfsds are started".
Signed-off-by: NGreg Banks <gnb@sgi.com>
Signed-off-by: NHarshula Jayasuriya <harshula@sgi.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Stop gathering the data that feeds the 'th' line in /proc/net/rpc/nfsd
because the questionable data provided is not worth the scalability
impact of calculating it.  Instead, always report zeroes.  The current
approach suffers from three major issues:

1. update_thread_usage() increments buckets by call service
   time or call arrival time...in jiffies.  On lightly loaded
   machines, call service times are usually < 1 jiffy; on
   heavily loaded machines call arrival times will be << 1 jiffy.
   So a large portion of the updates to the buckets are rounded
   down to zero, and the histogram is undercounting.

2. As seen previously on the nfs mailing list, the format in which
   the histogram is presented is cryptic, difficult to explain,
   and difficult to use.

3. Updating the histogram requires taking a global spinlock and
   dirtying the global variables nfsd_last_call, nfsd_busy, and
   nfsdstats *twice* on every RPC call, which is a significant
   scaling limitation.

Testing on a 4 CPU 4 NIC Altix using 4 IRIX clients each doing
1K streaming reads at full line rate, shows the stats update code
(inlined into nfsd()) takes about 1.7% of each CPU.  This patch drops
the contribution from nfsd() into the profile noise.

This patch is a forward-ported version of knfsd-remove-nfsd-threadstats
which has been shipping in the SGI "Enhanced NFS" product since 2006.
In that time, exactly one customer has noticed that the threadstats
were missing.  It has been previously posted:

http://article.gmane.org/gmane.linux.nfs/10376

and more recently requested to be posted again.
Signed-off-by: NGreg Banks <gnb@sgi.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Note that we already checked for this invalid case at the top of this
function.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The main nfsd code was recently modified to no longer do lookups from
withing the readdir callback, to avoid locking problems on certain
filesystems.

This (rather hacky, and overdue for replacement) NFSv4 recovery code has
the same problem.  Fix it to build up a list of names (instead of
dentries) and do the lookups afterwards.

Reported symptoms were a deadlock in the xfs code (called from
nfsd4_recdir_load), with /var/lib/nfs on xfs.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Reported-by: NDavid Warren <warren@atmos.washington.edu>

Currently putpubfh returns NFSERR_OPNOTSUPP, which isn't actually
allowed for v4.  The right error is probably NFSERR_NOTSUPP.

But let's just implement it; though rarely seen, it can be used by
Solaris (with a special mount option), is mandated by the rfc, and is
trivial for us to support.

Thanks to Yang Hongyang for pointing out the original problem, and to
Mike Eisler, Tom Talpey, Trond Myklebust, and Dave Noveck for further
argument....
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

If a filesystem being written to via NFS returns a short write count
(as opposed to an error) to nfsd, nfsd treats that as a success for
the entire write, rather than the short count that actually succeeded.

For example, given a 8192 byte write, if the underlying filesystem
only writes 4096 bytes, nfsd will ack back to the nfs client that all
8192 bytes were written.  The nfs client does have retry logic for
short writes, but this is never called as the client is told the
complete write succeeded.

There are probably other ways it could happen, but in my case it
happened with a fuse (filesystem in userspace) filesystem which can
rather easily have a partial write.

Here is a patch to properly return the short write count to the
client.
Signed-off-by: NDavid Shaw <dshaw@jabberwocky.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Thanks for Bill Baker at sun.com for catching this
at Connectathon 2009.

This bug was introduced in 2.6.27
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The errors returned aren't used.  Just return 0 and make them available
to a dprintk().  Also, consistently use -ERRNO errors instead of nfs
errors.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Reviewed-by: NBenny Halevy <bhalevy@panasas.com>

As part of reducing the scope of the client_mutex, and in order to
remove the need for mutexes from the callback code (so that callbacks
can be done as asynchronous rpc calls), move manipulations of the
file_hashtable under the recall_lock.

Update the relevant comments while we're here.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Alexandros Batsakis <batsakis@netapp.com>
Reviewed-by: NBenny Halevy <bhalevy@panasas.com>

Since free_client() is guaranteed to only be called once, and to only
touch the client structure itself (not any common data structures), it
has no need for the state lock.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Alexandros Batsakis <batsakis@netapp.com>

Use a slightly clearer, more concise name.  Also removed unused
argument.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

All users now pass this, so it's meaningless.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Previous cleanup reveals an obvious (though harmless) bug: when
delegreturn gets a stateid that isn't for a delegation, it should return
an error rather than doing nothing.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Delegreturn is enough a special case for preprocess_stateid_op to
warrant just open-coding it in delegreturn.

There should be no change in behavior here; we're just reshuffling code.

Thanks to Yang Hongyang for catching a critical typo.
Reviewed-by: NYang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Make this check self-documenting.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

I can't recall ever seeing these printk's used to debug a problem.  I'll
happily put them back if we see a case where they'd be useful.  (Though
if we do that the find_XXX() errors would probably be better
reported in find_XXX() functions themselves.)
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

We no longer need stidp.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Note that we exit this first big "if" with stp == NULL if and only if we
took the first branch; therefore, the second "if" is redundant, and we
can just combine the two, simplifying the logic.
Reviewed-by: NYang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

No change in behavior.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Remove a couple redundant comments, adjust style; no change in behavior.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

sometimes HPUX nfs client sends a create request to linux nfs server(v2/v3).
the dump of the request is like:
    obj_attributes
        mode: value follows
            set_it: value follows (1)
            mode: 00
        uid: no value
            set_it: no value (0)
        gid: value follows
            set_it: value follows (1)
            gid: 8030
        size: value follows
            set_it: value follows (1)
            size: 0
        atime: don't change
            set_it: don't change (0)
        mtime: don't change
            set_it: don't change (0)

note that mode is 00(havs no rwx privilege even for the owner) and it requires
to set size to 0.

as current nfsd(v2/v3) implementation, the server does mainly 2 steps:
1) creates the file in mode specified by calling vfs_create().
2) sets attributes for the file by calling nfsd_setattr().

at step 2), it finally calls file system specific setattr() function which may
fail when checking permission because changing size needs WRITE privilege but
it has none since mode is 000.

for this case, a new file created, we may simply ignore the request of
setting size to 0, so that WRITE privilege is not needed and the open
succeeds.
Signed-off-by: NWengang Wang <wen.gang.wang@oracle.com>
--
 vfs.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

not having the state locked before putting the client/delegation causes a bug.
Also removed the comment from the function header about the state being already locked
Signed-off-by: NAlexandros Batsakis <batsakis@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The use of |= is confusing--the bitmask is always initialized to zero in
this case, so we're effectively just doing an assignment here.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Enable NFSD only when FILE_LOCKING is enabled, since we don't want to
support NFSD without FILE_LOCKING.
Signed-off-by: NManish Katiyar <mkatiyar@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

MSDOS_SUPER_MAGIC is defined in <linux/magic.h>,
so use MSDOS_SUPER_MAGIC directly.
Signed-off-by: NQinghuang Feng <qhfeng.kernel@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The caller always knows specifically whether it's releasing a lockowner
or an openowner, and the code is simpler if we use separate functions
(and the apparent recursion is gone).
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The flags here attempt to make the code more general, but I find it
actually just adds confusion.

I think it's clearer to separate the logic for the open and lock cases
entirely.  And eventually we may want to separate the stateowner and
stateid types as well, as many of the fields aren't shared between the
lock and open cases.

Also move to eliminate forward references.

Start with the stateid's.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Reviewed-by: NBenny Halevy <bhalevy@panasas.com>

Although this operation is unsupported by our implementation
we still need to provide an encode routine for it to
merely encode its (error) status back in the compound reply.

Thanks for Bill Baker at sun.com for testing with the Sun
OpenSolaris' client, finding, and reporting this bug at
Connectathon 2009.

This bug was introduced in 2.6.27
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Cc: stable@kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

nfsd4_lockt does a search for a lockstateowner when building the lock
struct to test. If one is found, it'll set fl_owner to it. Regardless of
whether that happens, it'll also set fl_lmops. Given that this lock is
basically a "lightweight" lock that's just used for checking conflicts,
setting fl_lmops is probably not appropriate for it.

This behavior exposed a bug in DLM's GETLK implementation where it
wasn't clearing out the fields in the file_lock before filling in
conflicting lock info. While we were able to fix this in DLM, it
still seems pointless and dangerous to set the fl_lmops this way
when we may have a NULL lockstateowner.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@pig.fieldses.org>

Since override_creds() took its own reference on new, we need to release
our own reference.

(Note the put_cred on the return value puts the *old* value of
current->creds, not the new passed-in value).
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

We're forgetting to check the return value from groups_alloc().
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>

refactor the nfs4 server lock code to use last_byte_offset
to compute the last byte covered by the lock.  Check for overflow
so that the last byte is set to NFS4_MAX_UINT64 if offset + len
wraps around.

Also, use NFS4_MAX_UINT64 for ~(u64)0 where appropriate.
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

There's no use for nfs4_cb_null_ops's declaration in fs/nfsd/nfs4callback.c
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>