Handle DS READ and WRITE stateid errors by recovering the stateid on the MDS.

NFS4ERR_OLD_STATEID is ignored as the client always sends a
state sequenceid of zero for DS READ and WRITE stateids.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

Change the name to reflect what we're really doing: testing two
stateids for whether or not they match according the the rules in
RFC3530 and RFC5661.
Move the code from callback_proc.c to nfs4proc.c
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

nfs41_validate_delegation_stateid is broken if we supply a stateid with
a non-zero sequence id. Instead of trying to match the sequence id,
the function assumes that we always want to error. While this is
true for a delegation callback, it is not true in general.

Also fix a typo in nfs4_callback_recall.
Reported-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we know that the delegation stateid is bad or revoked, we need to
remove that delegation as soon as possible, and then mark all the
stateids that relied on that delegation for recovery. We cannot use
the delegation as part of the recovery process.

Also note that NFSv4.1 uses a different error code (NFS4ERR_DELEG_REVOKED)
to indicate that the delegation was revoked.

Finally, ensure that setlk() and setattr() can both recover safely from
a revoked delegation.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

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

nfs_mark_return_delegation() is usually called without any locking, and
so it is not safe to dereference delegation->inode. Since the inode is
only used to discover the nfs_client anyway, it makes more sense to
have the callers pass a valid pointer to the nfs_server as a parameter.
Reported-by: NIan Kent <raven@themaw.net>
Cc: stable@kernel.org
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The rcu callback nfs_free_delegation_callback() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(nfs_free_delegation_callback).
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There is no reason to be freeing the delegation cred in the rcu callback,
and doing so is resulting in a lockdep complaint that rpc_credcache_lock
is being called from both softirq and non-softirq contexts.
Reported-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

Delegations are per-inode, not per-nfs_client.  When a server file
system is migrated, delegations on the client must be moved from the
source to the destination nfs_server.  Make it easier to manage a
mount point's delegation list across a migration event by moving the
list to the nfs_server struct.

Clean up: I added documenting comments to public functions I changed
in this patch.  For consistency I added comments to all the other
public functions in fs/nfs/delegation.c.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up:  Refactor code that takes clp->cl_lock and calls
nfs_detach_delegations_locked() into its own function.

While we're changing the call sites, get rid of the second parameter
and the logic in nfs_detach_delegations_locked() that uses it, since
callers always set that parameter of nfs_detach_delegations_locked()
to NULL.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The big kernel lock has been removed from all these files at some point,
leaving only the #include.

Remove this too as a cleanup.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This prepares the removal of the big kernel lock from the
file locking code. We still use the BKL as long as fs/lockd
uses it and ceph might sleep, but we can flip the definition
to a private spinlock as soon as that's done.
All users outside of fs/lockd get converted to use
lock_flocks() instead of lock_kernel() where appropriate.

Based on an earlier patch to use a spinlock from Matthew
Wilcox, who has attempted this a few times before, the
earliest patch from over 10 years ago turned it into
a semaphore, which ended up being slower than the BKL
and was subsequently reverted.

Someone should do some serious performance testing when
this becomes a spinlock, since this has caused problems
before. Using a spinlock should be at least as good
as the BKL in theory, but who knows...
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NMatthew Wilcox <willy@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Sage Weil <sage@newdream.net>
Cc: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org

There is no need to flush out writes before calling nfs_wb_all().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

We do not want to have the state recovery thread kick off and wait for a
memory reclaim, since that may deadlock when the writebacks end up
waiting for the state recovery thread to complete.

The safe thing is therefore to use GFP_NOFS in all open, close,
delegation return, lock, etc. operations that may be called by the
state recovery thread.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Fix a number of RCU issues in the NFSv4 delegation code.

 (1) delegation->cred doesn't need to be RCU protected as it's essentially an
     invariant refcounted structure.

     By the time we get to nfs_free_delegation(), the delegation is being
     released, so no one else should be attempting to use the saved
     credentials, and they can be cleared.

     However, since the list of delegations could still be under traversal at
     this point by such as nfs_client_return_marked_delegations(), the cred
     should be released in nfs_do_free_delegation() rather than in
     nfs_free_delegation().  Simply using rcu_assign_pointer() to clear it is
     insufficient as that doesn't stop the cred from being destroyed, and nor
     does calling put_rpccred() after call_rcu(), given that the latter is
     asynchronous.

 (2) nfs_detach_delegation_locked() and nfs_inode_set_delegation() should use
     rcu_derefence_protected() because they can only be called if
     nfs_client::cl_lock is held, and that guards against anyone changing
     nfsi->delegation under it.  Furthermore, the barrier imposed by
     rcu_dereference() is superfluous, given that the spin_lock() is also a
     barrier.

 (3) nfs_detach_delegation_locked() is now passed a pointer to the nfs_client
     struct so that it can issue lockdep advice based on clp->cl_lock for (2).

 (4) nfs_inode_return_delegation_noreclaim() and nfs_inode_return_delegation()
     should use rcu_access_pointer() outside the spinlocked region as they
     merely examine the pointer and don't follow it, thus rendering unnecessary
     the need to impose a partial ordering over the one item of interest.

     These result in an RCU warning like the following:

[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
fs/nfs/delegation.c:332 invoked rcu_dereference_check() without protection!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
2 locks held by mount.nfs4/2281:
 #0:  (&type->s_umount_key#34){+.+...}, at: [<ffffffff810b25b4>] deactivate_super+0x60/0x80
 #1:  (iprune_sem){+.+...}, at: [<ffffffff810c332a>] invalidate_inodes+0x39/0x13a

stack backtrace:
Pid: 2281, comm: mount.nfs4 Not tainted 2.6.34-rc1-cachefs #110
Call Trace:
 [<ffffffff8105149f>] lockdep_rcu_dereference+0xaa/0xb2
 [<ffffffffa00b4591>] nfs_inode_return_delegation_noreclaim+0x5b/0xa0 [nfs]
 [<ffffffffa0095d63>] nfs4_clear_inode+0x11/0x1e [nfs]
 [<ffffffff810c2d92>] clear_inode+0x9e/0xf8
 [<ffffffff810c3028>] dispose_list+0x67/0x10e
 [<ffffffff810c340d>] invalidate_inodes+0x11c/0x13a
 [<ffffffff810b1dc1>] generic_shutdown_super+0x42/0xf4
 [<ffffffff810b1ebe>] kill_anon_super+0x11/0x4f
 [<ffffffffa009893c>] nfs4_kill_super+0x3f/0x72 [nfs]
 [<ffffffff810b25bc>] deactivate_super+0x68/0x80
 [<ffffffff810c6744>] mntput_no_expire+0xbb/0xf8
 [<ffffffff810c681b>] release_mounts+0x9a/0xb0
 [<ffffffff810c689b>] put_mnt_ns+0x6a/0x79
 [<ffffffffa00983a1>] nfs_follow_remote_path+0x5a/0x146 [nfs]
 [<ffffffffa0098334>] ? nfs_do_root_mount+0x82/0x95 [nfs]
 [<ffffffffa00985a9>] nfs4_try_mount+0x75/0xaf [nfs]
 [<ffffffffa0098874>] nfs4_get_sb+0x291/0x31a [nfs]
 [<ffffffff810b2059>] vfs_kern_mount+0xb8/0x177
 [<ffffffff810b2176>] do_kern_mount+0x48/0xe8
 [<ffffffff810c810b>] do_mount+0x782/0x7f9
 [<ffffffff810c8205>] sys_mount+0x83/0xbe
 [<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b

Also on:

fs/nfs/delegation.c:215 invoked rcu_dereference_check() without protection!
 [<ffffffff8105149f>] lockdep_rcu_dereference+0xaa/0xb2
 [<ffffffffa00b4223>] nfs_inode_set_delegation+0xfe/0x219 [nfs]
 [<ffffffffa00a9c6f>] nfs4_opendata_to_nfs4_state+0x2c2/0x30d [nfs]
 [<ffffffffa00aa15d>] nfs4_do_open+0x2a6/0x3a6 [nfs]
 ...

And:

fs/nfs/delegation.c:40 invoked rcu_dereference_check() without protection!
 [<ffffffff8105149f>] lockdep_rcu_dereference+0xaa/0xb2
 [<ffffffffa00b3bef>] nfs_free_delegation+0x3d/0x6e [nfs]
 [<ffffffffa00b3e71>] nfs_do_return_delegation+0x26/0x30 [nfs]
 [<ffffffffa00b406a>] __nfs_inode_return_delegation+0x1ef/0x1fe [nfs]
 [<ffffffffa00b448a>] nfs_client_return_marked_delegations+0xc9/0x124 [nfs]
 ...
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that we correctly rcu-dereference the delegation itself, and that we
protect against removal while we're changing the contents.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

in NFSv4.1 the seqid part of a stateid in CB_RECALL must be 0
Signed-off-by: NAlexandros Batsakis <batsakis@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

For now the clients returns _all_ the delegations of the specificed type
it holds
Signed-off-by: NAlexandros Batsakis <batsakis@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

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

The nfsv4 state manager could potentially deadlock inside
__nfs_inode_return_delegation() if the server reboots, so that the calls to
nfs_msync_inode() end up waiting on state recovery to complete.

Also ensure that if a server reboot or network partition causes us to have
to stop returning delegations, that NFS4CLNT_DELEGRETURN is set so that
the state manager can resume any outstanding delegation returns after it
has dealt with the state recovery situation.

Finally, ensure that the state manager doesn't wait for the DELEGRETURN
call to complete. It doesn't need to, and that too can cause a deadlock.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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

The NFSv4 delegation recovery code is required by the protocol to handle
more errors. Rather than add NFSv4.0 specific errors into 'generic'
delegation code, we should move the error handling into the NFSv4 layer.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

If the client is not using a delegation, the right thing to do is to return
it as soon as possible. This helps reduce the amount of state the server
has to track, as well as reducing the potential for conflicts with other
clients.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Reuse the state management thread in order to return delegations when we
get a callback.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Let the actual delegreturn stuff be run in the state manager thread rather
than allocating a separate kthread.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It is really a more general purpose state management thread at this point.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Add a delegation cleanup phase to the state management loop, and do the
NFS4ERR_CB_PATH_DOWN recovery there.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Add a flag to mark delegations as requiring return, then run a garbage
collector. In the future, this will allow for more flexible delegation
management, where delegations may be marked for return if it turns out
that they are not being referenced.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Now that we're using the flags to indicate state that needs to be
recovered, as well as having implemented proper refcounting and spinlocking
on the state and open_owners, we can get rid of nfs_client->cl_sem. The
only remaining case that was dubious was the file locking, and that case is
now covered by the nfsi->rwsem.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

Without an extra lock, we cannot just assume that the delegation->inode is
valid when we're traversing the rcu-protected nfs_client lists. Use the
delegation->lock to ensure that it is truly valid.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When we can update_open_stateid(), we need to be certain that we don't
race with a delegation return. While we could do this by grabbing the
nfs_client->cl_lock, a dedicated spin lock in the delegation structure
will scale better.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4state.c:788:34: warning: Using plain integer as NULL pointer
fs/nfs/delegation.c:52:34: warning: Using plain integer as NULL pointer
fs/nfs/idmap.c:312:12: warning: Using plain integer as NULL pointer
fs/nfs/callback_xdr.c:257:6: warning: Using plain integer as NULL pointer
fs/nfs/callback_xdr.c:270:6: warning: Using plain integer as NULL pointer
fs/nfs/callback_xdr.c:281:6: warning: Using plain integer as NULL pointer
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>