This patch fixes an Oops that was reported by Gabriel Barazer.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This should fix the following Oops reported by Jeff Garzik:

kernel BUG at fs/nfs/nfs4xdr.c:1040!
invalid opcode: 0000 [1] SMP 
CPU 0 
Modules linked in: nfs lockd sunrpc af_packet
ipv6 cpufreq_ondemand acpi_cpufreq battery floppy nvram sg snd_hda_intel
ata_generic snd_pcm_oss snd_mixer_oss snd_pcm i2c_i801 snd_page_alloc e1000
firewire_ohci ata_piix i2c_core sr_mod cdrom sata_sil ahci libata sd_mod
scsi_mod ext3 jbd ehci_hcd uhci_hcd
Pid: 16353, comm: 10.10.10.1-recl Not tainted 2.6.23-rc3 #1
RIP: 0010:[<ffffffff88240980>] [<ffffffff88240980>] :nfs:encode_open+0x1c0/0x330
RSP: 0018:ffff8100467c5c60  EFLAGS: 00010202
RAX: ffff81000f89b8b8 RBX: 00000000697a6f6d RCX: ffff81000f89b8b8
RDX: 0000000000000004 RSI: 0000000000000004 RDI: ffff8100467c5c80
RBP: ffff8100467c5c80 R08: ffff81000f89bc30 R09: ffff81000f89b83f
R10: 0000000000000001 R11: ffffffff881e79e0 R12: ffff81003cbd1808
R13: ffff81000f89b860 R14: ffff81005fc984e0 R15: ffffffff88240af0
FS:  0000000000000000(0000) GS:ffffffff8052a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 00002adb9e51a030 CR3: 000000007ea7e000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process 10.10.10.1-recl (pid: 16353, threadinfo ffff8100467c4000, task ffff8100038ce780)
Stack:  ffff81004aeb6a40 ffff81003cbd1808 ffff81003cbd1808 ffffffff88240b5d
 ffff81000f89b8bc ffff81005fc984e8 ffff81000f89bc30 ffff81005fc984e8
 0000000300000000 0000000000000000 0000000000000000 ffff81003cbd1800
Call Trace:
 [<ffffffff88240b5d>] :nfs:nfs4_xdr_enc_open_noattr+0x6d/0x90
 [<ffffffff881e74b7>] :sunrpc:rpcauth_wrap_req+0x97/0xf0
 [<ffffffff88240af0>] :nfs:nfs4_xdr_enc_open_noattr+0x0/0x90
 [<ffffffff881df57a>] :sunrpc:call_transmit+0x18a/0x290
 [<ffffffff881e5e7b>] :sunrpc:__rpc_execute+0x6b/0x290
 [<ffffffff881dff76>] :sunrpc:rpc_do_run_task+0x76/0xd0
 [<ffffffff882373f6>] :nfs:_nfs4_proc_open+0x76/0x230
 [<ffffffff88237a2e>] :nfs:nfs4_open_recover_helper+0x5e/0xc0
 [<ffffffff88237b74>] :nfs:nfs4_open_recover+0xe4/0x120
 [<ffffffff88238e14>] :nfs:nfs4_open_reclaim+0xa4/0xf0
 [<ffffffff882413c5>] :nfs:nfs4_reclaim_open_state+0x55/0x1b0
 [<ffffffff882417ea>] :nfs:reclaimer+0x2ca/0x390
 [<ffffffff88241520>] :nfs:reclaimer+0x0/0x390
 [<ffffffff8024e59b>] kthread+0x4b/0x80
 [<ffffffff8020cad8>] child_rip+0xa/0x12
 [<ffffffff8024e550>] kthread+0x0/0x80
 [<ffffffff8020cace>] child_rip+0x0/0x12


Code: 0f 0b eb fe 48 89 ef c7 00 00 00 00 02 be 08 00 00 00 e8 79 
RIP  [<ffffffff88240980>] :nfs:encode_open+0x1c0/0x330
 RSP <ffff8100467c5c60>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Do not allow cached open for O_RDONLY or O_WRONLY unless the file has been
previously opened in these modes.

Also Fix the calculation of the mode in nfs4_close_prepare. We should only
issue an OPEN_DOWNGRADE if we're sure that we will still be holding the
correct open modes. This may not be the case if we've been doing delegated
opens.

Finally, there is no need to adjust the open mode bit flags in
nfs4_close_done(): that has already been done in nfs4_close_prepare().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Fix a couple of bugs:
 - Don't rely on the parent dentry still being valid when the call completes.
   Fixes a race with shrink_dcache_for_umount_subtree()

 - Don't remove the file if the filehandle has been labelled as stale.

Fix a couple of inefficiencies
 - Remove the global list of sillyrenamed files. Instead we can cache the
   sillyrename information in the dentry->d_fsdata
 - Move common code from unlink_setup/unlink_done into fs/nfs/unlink.c
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We need a common structure for setting up an unlink() rpc call in order to
fix the asynchronous unlink code.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Try harder to recover the open state if the server failed to return a
filehandle.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

Ensure that opendata->state is always initialised when we do state
recovery.

Ensure that we set the filehandle in the case where we're doing an
"OPEN_CLAIM_PREVIOUS" call due to a server reboot.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

I ran into a curious issue when a lock is being canceled. The
cancellation results in a lock request to the vfs layer instead of an
unlock request. This is particularly insidious when the process that
owns the lock is exiting. In that case, sometimes the erroneous lock is
applied AFTER the process has entered zombie state, preventing the lock
from ever being released. Eventually other processes block on the lock
causing a slow degredation of the system. In the 2.6.16 kernel this was
investigated on, the problem is compounded by the fact that the cl_sem
is held while blocking on the vfs lock, which results in most processes
accessing the nfs file system in question hanging.

In more detail, here is how the situation occurs:

first _nfs4_do_setlk():

static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *fl, int reclaim)
...
        ret = nfs4_wait_for_completion_rpc_task(task);
        if (ret == 0) {
...
        } else
                data->cancelled = 1;

then nfs4_lock_release():

static void nfs4_lock_release(void *calldata)
...
        if (data->cancelled != 0) {
                struct rpc_task *task;
                task = nfs4_do_unlck(&data->fl, data->ctx, data->lsp,
                                data->arg.lock_seqid);

The problem is the same file_lock that was passed in to _nfs4_do_setlk()
gets passed to nfs4_do_unlck() from nfs4_lock_release(). So the type is
still F_RDLCK or FWRLCK, not F_UNLCK. At some point, when cancelling the
lock, the type needs to be changed to F_UNLCK. It seemed easiest to do
that in nfs4_do_unlck(), but it could be done in nfs4_lock_release().
The concern I had with doing it there was if something still needed the
original file_lock, though it turns out the original file_lock still
needs to be modified by nfs4_do_unlck() because nfs4_do_unlck() uses the
original file_lock to pass to the vfs layer, and a copy of the original
file_lock for the RPC request.

It seems like the simplest solution is to force all situations where
nfs4_do_unlck() is being used to result in an unlock, so with that in
mind, I made the following change:
Signed-off-by: NFrank Filz <ffilzlnx@us.ibm.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We really don't need to grab both the state->so_owner and the
inode->i_lock.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Rely on nfs4_try_open_cached() when appropriate.

Also fix an RCU violation in _nfs4_do_open_reclaim()
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we already have a stateid with the correct open mode for a given file,
then we can reuse that stateid instead of re-issuing an OPEN call without
violating the close-to-open caching semantics.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We should not be calling open() on an inode that has a delegation unless
we're doing a reclaim.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Use a flag instead of the 'data->rpc_status = -ENOMEM hack.
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>

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>

Don't clobber the delegation info...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This ensures that nfs4_open_release() and nfs4_open_confirm_release()
can now handle an eventual delegation that was returned with out open.
As such, it fixes a delegation "leak" when the user breaks out of an open
call.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently we do not check for the FMODE_EXEC flag as we should. For that
particular case, we need to perform an ACCESS call to the server in order
to check that the file is executable.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently we just use a 32-bit counter.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

They differ only slightly in the arguments they take. Why have they not
been merged?
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

The Linux NFS4 client simply skips over the bitmask in an O_EXCL open
call and so it doesn't bother to reset any fields that may be holding
the verifier. This patch has us save the first two words of the bitmask
(which is all the current client has #defines for). The client then
later checks this bitmask and turns on the appropriate flags in the
sattr->ia_verify field for the following SETATTR call.

This patch only currently checks to see if the server used the atime
and mtime slots for the verifier (which is what the Linux server uses
for this). I'm not sure of what other fields the server could
reasonably use, but adding checks for others should be trivial.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Use rpc_run_task() instead of doing it ourselves.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

nfs4_do_close() does not currently have any way to ensure that the user
won't attempt to unmount the partition while the asynchronous RPC call
is completing. This again may cause Oopses in nfs_update_inode().

Add a vfsmount argument to nfs4_close_state to ensure that the partition
remains mounted while we're closing the file.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

A number of race conditions may currently ensue if the user presses ^C
and then unmounts the partition while an asynchronous open() is in
progress.
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>

 - fs/nfs/dir.c:610:8: warning: symbol 'nfs_llseek_dir' was not declared.
   Should it be static?
 - fs/nfs/dir.c:636:5: warning: symbol 'nfs_fsync_dir' was not declared.
   Should it be static?
 - fs/nfs/write.c:925:19: warning: symbol 'req' shadows an earlier one
 - fs/nfs/write.c:61:6: warning: symbol 'nfs_commit_rcu_free' was not
   declared. Should it be static?
 - fs/nfs/nfs4proc.c:793:5: warning: symbol 'nfs4_recover_expired_lease'
   was not declared. Should it be static?
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The file_lock argument to ->lock is used to return the conflicting lock
when found.  There's no reason for the filesystem to return any private
information with this conflicting lock, but nfsv4 is.

Fix nfsv4 client, and modify locks.c to stop calling fl_release_private
for it in this case.
Signed-off-by: N"J. Bruce Fields" <bfields@citi.umich.edu>
Cc: "Trond Myklebust" <Trond.Myklebust@netapp.com>"

The ACL that the server sets may not be exactly the one we set--for
example, it may silently turn off bits that it does not support.  So we
should remove any cached ACL so that any subsequent request for the ACL
will go to the server.
Signed-off-by: N"J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Attempt to detect deadlocks due to caller holding locks on clp->cl_sem
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We might not even have any open files at this point...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It makes no sense to maintain 2 parallel systems for reading in pages.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Start long arduous project...  What the hell is

	struct dentry = {};

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

Run this:

	#!/bin/sh
	for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
	  echo "De-casting $f..."
	  perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
	done

And then go through and reinstate those cases where code is casting pointers
to non-pointers.

And then drop a few hunks which conflicted with outstanding work.

Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>