The order of the following three spinlocks should be:
dlm_domain_lock < dlm_ctxt->spinlock < dlm_lock_resource->spinlock

But dlm_dispatch_assert_master() is called while holding
dlm_ctxt->spinlock and dlm_lock_resource->spinlock, and then it calls
dlm_grab() which will take dlm_domain_lock.

Once another thread (for example, dlm_query_join_handler) has already
taken dlm_domain_lock, and tries to take dlm_ctxt->spinlock deadlock
happens.
Signed-off-by: NJoseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: "Junxiao Bi" <junxiao.bi@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following case will lead to a lockres is freed but is still in use.

cat /sys/kernel/debug/o2dlm/locking_state	dlm_thread
lockres_seq_start
    -> lock dlm->track_lock
    -> get resA
                                                resA->refs decrease to 0,
                                                call dlm_lockres_release,
                                                and wait for "cat" unlock.
Although resA->refs is already set to 0,
increase resA->refs, and then unlock
                                                lock dlm->track_lock
                                                    -> list_del_init()
                                                    -> unlock
                                                    -> free resA

In such a race case, invalid address access may occurs.  So we should
delete list res->tracking before resA->refs decrease to 0.
Signed-off-by: NYiwen Jiang <jiangyiwen@huawei.com>
Reviewed-by: NJoseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NMark Fasheh <mfasheh@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a race window in dlm_get_lock_resource(), which may return a
lock resource which has been purged.  This will cause the process to
hang forever in dlmlock() as the ast msg can't be handled due to its
lock resource not existing.

    dlm_get_lock_resource {
        ...
        spin_lock(&dlm->spinlock);
        tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
        if (tmpres) {
             spin_unlock(&dlm->spinlock);
             >>>>>>>> race window, dlm_run_purge_list() may run and purge
                              the lock resource
             spin_lock(&tmpres->spinlock);
             ...
             spin_unlock(&tmpres->spinlock);
        }
    }
Signed-off-by: NJunxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit ac4fef4d ("ocfs2/dlm: do not purge lockres that is queued for
assert master") may have the following possible race case:

  dlm_dispatch_assert_master       dlm_wq
  ========================================================================
  queue_work(dlm->quedlm_worker,
      &dlm->dispatched_work);
                                 dispatch work,
                                 dlm_lockres_drop_inflight_worker
                                 *BUG_ON(res->inflight_assert_workers == 0)*
  dlm_lockres_grab_inflight_worker
  inflight_assert_workers++

So ensure inflight_assert_workers to be increased first.
Signed-off-by: NJoseph Qi <joseph.qi@huawei.com>
Signed-off-by: NXue jiufei <xuejiufei@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Node A sends master query request to node B which is the master.  At this
time lockres happens to be on purgelist.  dlm_master_request_handler gets
the dlm spinlock, finds the resource and releases the dlm spin lock.
Right at this dlm_thread on this node could purge the lockres.
dlm_master_request_handler can then acquire lockres spinlock and reply to
Node A that node B is the master even though lockres on node B is purged.

The above scenario will now make node A falsely think node B is the master
which is inconsistent.  Further if another node C tries to master the same
resource, every node will respond they are not the master.  Node C then
masters the resource and sends assert master to all nodes.  This will now
make node A crash with the following message.

dlm_assert_master_handler:1831 ERROR: DIE! Mastery assert from 9, but current
owner is 10!
Signed-off-by: NSrinivas Eeda <srinivas.eeda@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Reviewed-by: NWengang Wang <wen.gang.wang@oracle.com>
Tested-by: NJoseph Qi <joseph.qi@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove the branch that free res->lockname.name because the condition
is never satisfied when jump to label error.
Signed-off-by: Njoyce.xue <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In dlm_assert_master_handler, the mle is get in dlm_find_mle, should be
put when goto kill, otherwise, this mle will never be released.
Signed-off-by: NAlex Chen <alex.chen@huawei.com>
Reviewed-by: NJoseph Qi <joseph.qi@huawei.com>
Reviewed-by: Njoyce.xue <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a deadlock case which reported by Guozhonghua:
  https://oss.oracle.com/pipermail/ocfs2-devel/2014-September/010079.html

This case is caused by &res->spinlock and &dlm->master_lock
misordering in different threads.

It was introduced by commit 8d400b81 ("ocfs2/dlm: Clean up refmap
helpers").  Since lockres is new, it doesn't not require the
&res->spinlock.  So remove it.

Fixes: 8d400b81 ("ocfs2/dlm: Clean up refmap helpers")
Signed-off-by: NJoseph Qi <joseph.qi@huawei.com>
Reviewed-by: Njoyce.xue <xuejiufei@huawei.com>
Reported-by: NGuozhonghua <guozhonghua@h3c.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Orabug: 19074140

When umount is issued during recovery on the new master that has not
finished remastering locks, it triggers BUG() in
dlm_send_mig_lockres_msg().  Here is the situation:

 1) node A has a lock on resource X mastered by node B.

 2) node B dies ->  node A sets recovering flag for res X

 3) Node C becomes the new master for resources owned by the
    dead node and is remastering locks of the dead node but
    has not finished the remastering process yet.

 4) umount is issued on node C.

 5) During processing of umount, ignoring unfished recovery,
    node C attempts to migrate resource X to node A.

 6) node A finds res X in DLM_LOCK_RES_RECOVERING state, considers
    it a logic error and sends back -EFAULT.

 7) node C asserts BUG() upon seeing EFAULT resp from node B.

Fix is to delay migrating res X till remastering is finished at which
point recovering flag will be cleared on both A and C.
Signed-off-by: NTariq Saeed <tariq.x.saeed@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When workqueue is delayed, it may occur that a lockres is purged while it
is still queued for master assert.  it may trigger BUG() as follows.

N1                                         N2
dlm_get_lockres()
->dlm_do_master_requery
                                  is the master of lockres,
                                  so queue assert_master work

                                  dlm_thread() start running
                                  and purge the lockres

                                  dlm_assert_master_worker()
                                  send assert master message
                                  to other nodes
receiving the assert_master
message, set master to N2

dlmlock_remote() send create_lock message to N2, but receive DLM_IVLOCKID,
if it is RECOVERY lockres, it triggers the BUG().

Another BUG() is triggered when N3 become the new master and send
assert_master to N1, N1 will trigger the BUG() because owner doesn't
match.  So we should not purge lockres when it is queued for assert
master.
Signed-off-by: Njoyce.xue <xuejiufei@huawei.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following case may lead to endless loop during umount.

node A         node B               node C       node D
umount volume,
migrate lockres1
to B
                                                 want to lock lockres1,
                                                 send
                                                 MASTER_REQUEST_MSG
                                                 to C
                                    init block mle
               send
               MIGRATE_REQUEST_MSG
               to C
                                    find a block
                                    mle, and then
                                    return
                                    DLM_MIGRATE_RESPONSE_MASTERY_REF
                                    to B
               set C in refmap
                                    umount successfully
               try to umount, endless
               loop occurs when migrate
               lockres1 since C is in
               refmap

So we can fix this endless loop case by only returning
DLM_MIGRATE_RESPONSE_MASTERY_REF if it has a mastery mle when receiving
MIGRATE_REQUEST_MSG.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Njiangyiwen <jiangyiwen@huawei.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Xue jiufei <xuejiufei@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Static values are automatically initialized to NULL.
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In dlm_init, if create dlm_lockname_cache failed in
dlm_init_master_caches, it will destroy dlm_lockres_cache which created
before twice.  And this will cause system die when loading modules.
Signed-off-by: NJoseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NJunxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: NJoel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We trigger a bug in __dlm_lockres_reserve_ast() when we parallel umount 4
nodes.  The situation is as follows:

1) Node A migrate all lockres it owned(eg.  lockres A) to other nodes
   say node B when it umounts.

2) Receiving MIG_LOCKRES message from A, Node B masters the lockres A
   with DLM_LOCK_RES_MIGRATING state set.

3) Then we umount ocfs2 on node B.  It also should migrate lockres A to
   another node, say node C.  But now, DLM_LOCK_RES_MIGRATING state of
   lockers A is not cleared.  Node B triggered the BUG on lockres with
   state DLM_LOCK_RES_MIGRATING.
Signed-off-by: NXuejiufei <xuejiufei@huawei.com>
Signed-off-by: NJoel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Tariq Saeed <tariq.x.saeed@oracle.com>
Cc: Srinivas Eeda <srinivas.eeda@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

[dan.carpenter@oracle.com: fix up some NULL dereference bugs]
Signed-off-by: NDong Fang <yp.fangdong@gmail.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jeff Liu <jeff.liu@oracle.com>
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

My static checker complains that this is called with a spin_lock held
in dlm_master_requery_handler() from dlmrecovery.c.  Probably the reason
we have not received any bug reports about this is that recovery is not
a common operation.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJoel Becker <jlbec@evilplan.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The inflight reference count, in the lock resource, is taken to pin the resource
in memory. We take it when a new resource is created and release it after a
lock is attached to it. We do this to prevent the resource from getting purged
prematurely.

Earlier this reference count was being taken for locally mastered resources
only. This patch extends the same functionality for remotely mastered ones.

We are doing this because the same premature purging could occur for remotely
mastered resources if the remote node were to die before completion of the
create lock.

Fix for Oracle bug#12405575.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

Patch cleans up helpers that set/clear refmap bits and grab/drop inflight lock
ref counts.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

o2dlm messages needed a facelift.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

During dlm domain shutdown, o2dlm has to free all the lock resources. Ones that
have no locks and references are freed. Ones that have locks and/or references
are migrated to another node.

The first task in migration is finding a target. Currently we scan the lock
resource and find one node that either has a lock or a reference. This is not
very efficient in a parallel umount case as we might end up migrating the
lock resource to a node which itself may have to migrate it to a third node.

The patch scans the dlm->exit_domain_map to ensure the target node is not
leaving the domain. If no valid target node is found, o2dlm does not migrate
the resource but instead waits for the unlock and deref messages that will
allow it to free the resource.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NJoel Becker <jlbec@evilplan.org>

Patch cleans up the gunk added by commit 388c4bcb.
dlm_is_lockres_migrateable() now returns 1 if lockresource is deemed
migrateable and 0 if not.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NJoel Becker <jlbec@evilplan.org>

During resource migration, if the target node were to die, the thread doing
the migration spins until the target node is not removed from the domain map.
This patch slows the spin by making the thread wait for the recovery to kick in.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NJoel Becker <jlbec@evilplan.org>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

ENTRY is used to record the entry of a function.
But because it is added in so many functions, if we enable it,
the system logs get filled up quickly and cause too much I/O.
So actually no one can open it for a production system or even
for a test.

So for mlog_entry_void, we just remove it.
for mlog_entry(...), we replace it with mlog(0,...), and they
will be replace by trace event later.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>

o2dlm was not migrating resources with zero locks because it assumed that that
resource would get purged by dlm_thread. However, some usage patterns involve
creating and dropping locks at a high rate leading to the migrate thread seeing
zero locks but the purge thread seeing an active reference. When this happens,
the dlm_thread cannot purge the resource and the migrate thread sees no reason
to migrate that resource. The spell is broken when the migrate thread catches
the resource with a lock.

The fix is to make the migrate thread also consider the reference map.

This usage pattern can be triggered by userspace on userdlm locks and flocks.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

While umounting, a block mle doesn't get freed if dlm is shutdown after
master request is received but before assert master. This results in unclean
shutdown of dlm domain.

This patch frees all mles that lie around after other nodes were notified about
exiting the dlm and marking dlm state as leaving. Only block mles are expected
to be around, so we log ERROR for other mles but still free them.
Signed-off-by: NSrinivas Eeda <srinivas.eeda@oracle.com>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

When we need to take both dlm_domain_lock and dlm->spinlock, we should take
them in order of: dlm_domain_lock then dlm->spinlock.

There is pathes disobey this order. That is calling dlm_lockres_put() with
dlm->spinlock held in dlm_run_purge_list. dlm_lockres_put() calls dlm_put() at
the ref and dlm_put() locks on dlm_domain_lock.

Fix:
Don't grab/put the dlm when the initialising/releasing lockres.
That grab is not required because we don't call dlm_unregister_domain()
based on refcount.
Signed-off-by: NWengang Wang <wen.gang.wang@oracle.com>
Cc: stable@kernel.org
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

When we have to take both dlm->master_lock and lockres->spinlock,
take them in order

lockres->spinlock and then dlm->master_lock.

The patch fixes a violation of the rule.
We can simply move taking dlm->master_lock to where we have dropped res->spinlock
since when we access res->state and free mle memory we don't need master_lock's
protection.
Signed-off-by: NWengang Wang <wen.gang.wang@oracle.com>
Cc: stable@kernel.org
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

For migration, we are waiting for DLM_LOCK_RES_MIGRATING flag to be set
before sending DLM_MIG_LOCKRES_MSG message to the target. We are using
dlm_migration_can_proceed() for that purpose.  However, if the node is
down, dlm_migration_can_proceed() will also return "go ahead".  In this
rare case, the DLM_LOCK_RES_MIGRATING flag might not be set yet. Remove
the BUG_ON() that trips over this condition.
Signed-off-by: NWengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Drop cast on the result of kmalloc and similar functions.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
type T;
@@

- (T *)
  (\(kmalloc\|kzalloc\|kcalloc\|kmem_cache_alloc\|kmem_cache_zalloc\|
   kmem_cache_alloc_node\|kmalloc_node\|kzalloc_node\)(...))
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Print the node number of a peer node if sending it a message failed.
Signed-off-by: NWengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

In o2dlm, the master of a lock resource keeps a map of all interested
nodes.  This prevents the master from purging the resource before an
interested node can create a lock.

A race between the mastery thread and the mastery handler allowed an
interested node to discover who the master is without informing the
master directly.  This is easily fixed by holding the dlm spinlock a
little longer in the mastery handler.
Signed-off-by: NSrinivas Eeda <srinivas.eeda@oracle.com>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

Patch removes trailing whitespaces.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

* remove asm/atomic.h inclusion from linux/utsname.h --
   not needed after kref conversion
 * remove linux/utsname.h inclusion from files which do not need it

NOTE: it looks like fs/binfmt_elf.c do not need utsname.h, however
due to some personality stuff it _is_ needed -- cowardly leave ELF-related
headers and files alone.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch removes struct dlm_lock_name and adds the entries directly
to struct dlm_master_list_entry. Under the new scheme, both mles that
are backed by a lockres or not, will have the name populated in mle->mname.
This allows us to get rid of code that was figuring out the location of
the mle name.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

This patch inlines dlm_set_lockres_owner() and dlm_change_lockres_owner().
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

This patch replaces the lockres counts that tracked the number number of
locally and remotely mastered lockres' with a current and total count. The
total count is the number of lockres' that have been created since the dlm
domain was created.

The number of locally and remotely mastered counts can be computed using
the locking_state output.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

The lifetime of a mle is limited to the duration of the lockres mastery
process. While typically this lifetime is fairly short, we have noticed
the number of mles explode under certain circumstances. This patch tracks
the number of each different types of mles and should help us determine
how best to speed up the mastery process.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>