This patch makes three small changes to nfsd_readdir().

First, the 'filldir' routine for NFSv4 may return an arbitrary error,
which should become the return value for nfsd_readdir().  I implemented
this by adding an 'nfserr' field to the 'struct readdir_cd'.

Second, in NFSv4 the caller of nfsd_readdir() will specify an attribute
bitmap, which must be communicated to the 'filldir' routine.  I implemented
this by adding a @bitmap parameter to nfsd_readdir() and a corresponding
field in the 'struct readdir_cd'.  (The bitmap is not interpreted in any
way by nfsd_readdir().)

Finally, NFSv4 defines a new error nfserr_readdir_nospc, which indicates
that there was not enough buffer space to encode a single entry.

NFSv4 defines a new field in the ACCESS response: a bitmap to indicate
which access bits requested by the client are "supported", i.e. meaningful
for the object in question.

This patch adds a new parameter @supported to nfsd_access(), so that
nfsd_access() can set the value of this bitmap.

File creation in NFSv4 is almost the same as in NFSv3, with one minor
difference.  If an UNCHECKED create is done, and the file exists, we
don't set any attributes.  Exception: If size==0 is specified as part
of the attributes, then we do truncate the file, but only after processing
the rest of the OPEN.  (File creation is always part of an OPEN request.)

This patch defines a new argument *truncp to nfsd_create_v3(), which
will be NULL for v3 requests.  For v4 requests, it will point to a
variable which should be set to 1 if file truncation is still needed.

The logic in nfsd_create_v3() is changed as follows: If
  - *truncp is not NULL
  - the create is UNCHECKED
  - the file exists
then nfsd_create_v3() returns immediately.  If size==0 is specified,
then *truncp is set to 1.

This is kind of a hack, but the only alternative I could see was creating
a new routine nfsd_create_v4(), which would be identical to nfsd_create_v3()
except for this point.

If nfsd_unlink() is called with @type equal to 0, then let it do the
right thing regardless of the type of the file being unlinked.  This
is needed for the NFSv4 REMOVE operation, which works for any type of
file, even directories.

Sanity check COMMIT arguments by ensuring that (start)+(length) < 2^64.
The check is done in a way which is free of signedness pathologies in
all cases.

This change was inspired by pynfs, Peter Astrand's regression testsuite
for NFSv4 servers.  The change is necessary for all of the COMMIT tests
to pass.  However, it's a little open to debate whether the change is
really needed.  I'm curious to hear the opinions of other developers.

Change fh_compose() so that it will do the right thing if fhp==res_fh.
(This is convenient in the NFSv4 LOOKUP operation, which _replaces_
CURRENT_FH with the filehandle obtained by lookup.)

This requires extracting the interesting parts of the reference
filehandle first, then calling fh_put if it is a re-use.

When a filehandle is cleared with fh_put(), wipe out all traces by
clearing ->fh_pre_saved and ->fh_post_saved.  This prevents
fill_post_wcc() from complaining if the filehandle is later reused.
(This could happen in NFSv4 to CURRENT_FH if, for example, LOOKUP LOOKUP
occurs in a COMPOUND.)

Return nfserr_nofilehandle (v4 only) in fh_verify() if the filehandle
has not been set.

In a few places on the server, I had to change code that looked like:

   if (rqstp->rq_vers == 3)
       /* NFSv3 behavior */
   else
       /* NFSv2 behavior */

to:

   if (rqstp->rq_vers > 2)
       /* NFSv3 behavior */
   else
       /* NFSv2 behavior */

so that we would get the NFSv3 behavior, not the NFSv2 behavior,
in NFSv4.  This patch collects all changes of this type.

Change the type checking in fh_verify().  This fixes a bug which
I reported on the mailing list a few days ago, and also adds a
new error code nfserr_symlink (v4 only).  This is returned whenever
an operation which is illegal for symlinks is attempted on a symlink,
and takes precedence over ERR_NOTDIR or ERR_INVAL.

Add some new NFSv4-only error codes to include/linux/nfsd/nfsd.h

This patch adds new NFSv4-only error codes to include/linux/nfs.h,
and also indicates which of the old error codes still exist in NFSv4.

If we get here, then bio->bi_bdev isn't set, so we really
shouldn't de-reference it.

..as some standard ioctls expect the per-device ioctl routine
to return EINVAL and then fall back on a standard implementation.

raid1, raid5 and multipath maintain their own
'operational' flag.  This is equivalent to
   !rdev->faulty
and so isn't needed.
Similarly raid1 and raid1 maintain a "write_only" flag
that is equivalnt to
   !rdev->in_sync
so it isn't needed either.

As part of implementing this change, we introduce some extra
flag bit in raid5 that are meaningful only inside 'handle_stripe'.
Some of these replace the "action" array which recorded what
actions were required (and would be performed after the stripe
spinlock was released).  This has the advantage of reducing our
dependance on MD_SB_DISKS which personalities shouldn't need
to know about.

This flag was used by multipath to make sure only
one superblock was written, as there is only one
real device.

The relevant test is now more explicitly dependant on multipath,
and the flag is gone.

Instread of the 'skip' variable, just test if rdev is NULL or not.

1/ Personalities only know about raid_disks devices.
   Some might be not in_sync and so cannot be read from,
   but must be written to.
	- change MD_SB_DISKS to ->raid_disks
	- add tests for .write_only

2/ rdev->raid_disk is now -1 for spares.  desc_nr is maintained
   by analyse_sbs and sync_sbs.

3/ spare_inactive method is subsumed into hot_remove_disk
   spare_writable is subsumed into hot_add_disk.
   hot_add_disk decides which slot a new device will hold.

4/ spare_active now finds all non-in_sync devices and marks them
   in_sync.

5/ faulty devices are removed by the md recovery thread as soon
   as they are idle.  Any spares that are available are then added.

This is equivalent to ->rdev != NULL, so it isn't needed.

This will allow us to know, in the event of a device failure, when the
device is completely unused and so can be disconnected from the
array.  Currently this isn't a problem as drives aren't normally disconnect
until after a repacement has been rebuilt, which is a LONG TIME, but that
will change shortly...

We always increment the count under a spinlock after checking that
it hasn't been disconnected already (rdev!= NULL).
We disconnect under the same spinlock after checking that the
count is zero.

This simplifies the error handlers slighty, but allows for even more
simplification later.

Holding the rdev instead of the bdev does cause an extra
de-reference, but it is conceptually cleaner and will allow
lots more tidying up.

->major_name is "const char *" so we need to sprintf into the kmalloced
space *before* assigning that space to ->major_name.

1/ Raid0 should not be accessing rdev->sb.

2/ Don't unlock rdev (which releases bdev) until after last use of bdev

3/ Fix typo in a printk ( = should be -)

4/ i should be dd_idx in compute_block

bufsiz is re-evaluated on recv if SK_CHNGBUF is set,
but recv will never be reached if the buffers are too small.
So we have to set to to something vaguely reasonable
at init time.

1/ connect requests would be get lost...
  As the comment at the top of svcsock.c says when discussing
  SK_CONN:
 *		after a set, svc_sock_enqueue must be called.

  We didn't and so lost conneciton requests.

2/ set the max accept backlog to a more reasonable number to cope
   with bursts of lots of connection requests.

__page_cache_release() needs to check PG_lru inside the lock, because
page reclaim may have taken the page off the LRU while this CPU waits
on the lock.

That's three bugs in a single twenty-line function.  So far.

This fixes some problems in vmalloc.c.  The two first parts of the diff
fix a spinlock being held if an error occurs in map_vm_area, and the
last part fixes the error path of __vmalloc.

but some files still did (and got the wrong results on UP).

Since they didn't actually _use_ the BKL anyway, remove the
include.

since it was generic.

Remove all architecture-specific <asm/smplock.h> files.

 - Use req->rq_received to determine the message length instead of
   assuming that it goes to the end of the page.

 - If the server returned an illegal record so that we cannot make
   progress by retrying the request on a fresh page, truncate the
   entire listing and return a syslog error.

 - Fix the check for whether or not the received message length has
   somehow been truncated: we need to use req->rq_received rather
   than the receive buffer length (req->rq_rlen).

 - Ensure that we set res->eof correctly. In particular, we need to
   clear it if we find ourselves attempting to recover from a
   truncated READ.

 - Don't set PageUptodate() on those pages that are the victim of
   message truncation.

 - cleanup #defines: I do not follow the rationale behind the
   odd line-wrapped defines at the beginning of the file.  If
   we have to use multiple lines, then we might as well do so
   cleanly and according to normal practice...

 - Remove a level of indirection: do not have spin_lock_foo
   use spin_lock - just explicitly call what is needed.

 - we do not need to define the spin_lock functions twice, once
   for CONFIG_PREEMPT and once for !CONFIG_PREEMPT.  Defining
   them once with the preempt macros will optimize away fine.

 - cleanup preempt.h too

 - other misc. cleanup, improved comments, reordering, etc.

This fixes the ptrace wait4() anomaly that can be observed in any
previous Linux kernel i could get my hands at.

If the parent still has other children (that are being traced by
somebody), we wait for them or return immediately without an error in
case of WNOHANG.