This patch bypasses multi-link errors in TCP mode, allowing dlm
to operate on the first tcp link.

Signed-off-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: David Teigland <teigland@redhat.com>

If an active rsb is not hashed anymore and this could occur because we
releases and acquired locks we need to signal the followed code that
the lookup failed. Since the lookup was successful, but it isn't part of
the rsb hash anymore we need to signal it by setting error to -EBADR as
dlm_search_rsb_tree() does it.

Cc: stable@vger.kernel.org
Fixes: 5be323b0c64d ("dlm: move dlm_search_rsb_tree() out of lock")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

If an inactive rsb is not hashed anymore and this could occur because we
releases and acquired locks we need to signal the followed code that the
lookup failed. Since the lookup was successful, but it isn't part of the
rsb hash anymore we need to signal it by setting error to -EBADR as
dlm_search_rsb_tree() does it.

Cc: stable@vger.kernel.org
Fixes: 01fdeca1cc2d ("dlm: use rcu to avoid an extra rsb struct lookup")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

do_uevent returns the value written to event_done. In case it is a
positive value, new_lockspace would undo all the work, and lockspace
would not be set. __dlm_new_lockspace, however, would treat that
positive value as a success due to commit 8511a2728ab8 ("dlm: fix use
count with multiple joins").

Down the line, device_create_lockspace would pass that NULL lockspace to
dlm_find_lockspace_local, leading to a NULL pointer dereference.

Treating such positive values as successes prevents the problem. Given
this has been broken for so long, this is unlikely to break userspace
expectations.

Fixes: 8511a2728ab8 ("dlm: fix use count with multiple joins")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Signed-off-by: David Teigland <teigland@redhat.com>

This patch increases the maximum number of links that can be
used with corosync3/knet. The majority of the changes are in
user space dlm_tools/dlm_controld.

Signed-off-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: David Teigland <teigland@redhat.com>

Currently if no comm can be found dlm_comm_seq() returns -EEXIST which
means entry already exists for a lookup it makes no sense to return
-EEXIST. We change it to -ENOENT. There is no user that will evaluate
the return value on a specific value so this should be fine.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

The return type of srcu_read_lock() is int and not bool. Whereas we
using the ret variable only to evaluate a bool type of
dlm_lowcomms_con_has_addr() to check if an address is already being set.

Fixes: 6f0b0b5d7ae7 ("fs: dlm: remove dlm_node_addrs lookup list")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

An rsb struct was not being removed in the case where it
was both the master and the dir record.  This case (master
and dir node) was missed in the condition for doing add_scan()
from deactivate_rsb().  Fixing this triggers a related WARN_ON
that needs to be fixed, and requires adjusting where two
del_scan() calls are made.

Fixes: c217adfc8caa ("dlm: fix add_scan and del_scan usage")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

If dlm_recover_members() fails we don't drop the references of the
previous created root_list that holds and keep all rsbs alive during the
recovery. It might be not an unlikely event because ping_members() could
run into an -EINTR if another recovery progress was triggered again.

Fixes: 3a747f4a2ee8 ("dlm: move rsb root_list to ls_recover() stack")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

In one special case, recovery is unable to reliably rebuild
lock state by simply recreating lkb structs as sent from the
lock holders.  That case is when the lkb's include conversions
between PR and CW modes.

The recovery code has always recognized this special case,
but the implemention has always been broken, and would set
invalid modes in recovered lkb's.  Unpredictable or bogus
errors could then be returned for further locking calls on
these locks.

This bug has gone unnoticed for so long due to some
combination of:
- applications never or infrequently converting between PR/CW
- recovery not occuring during these conversions
- if the recovery bug does occur, the caller may not notice,
  depending on what further locking calls are made, e.g. if
  the lock is simply unlocked it may go unnoticed

However, a core analysis from a recent gfs2 bug report points
to this broken code.

PR = Protected Read
CW = Concurrent Write
PR and CW are incompatible
PR and PR are compatible
CW and CW are compatible

Example 1

node C, resource R
granted: PR node A
granted: PR node B
granted: NL node C
granted: NL node D

- A sends convert PR->CW to C
- C fails before A gets a reply
- recovery occurs

At this point, A does not know if it still holds
the lock in PR, or if its conversion to CW was granted:
- If A's conversion to CW was granted, then another
  node's CW lock may also have been granted.
- If A's conversion to CW was not granted, it still
  holds a PR lock, and other nodes may also hold PR locks.

So, the new master of R cannot simply recreate the lock
from A using granted mode PR and requested mode CW.
The new master must look at all the recovered locks to
determine the correct granted modes, and ensure that all
the recovered locks are recreated in compatible states.

The correct lock recovery steps in this example are:
- node D becomes the new master of R
- node B sends D its lkb, granted PR
- node A sends D its lkb, convert PR->CW
- D determines the correct lock state is:
  granted: PR node B
  convert: PR->CW node A

The lkb sent by each node was recreated without
any change on the new master node.

Example 2

node C, resource R
granted: PR node A
granted: NL node C
granted: NL node D
waiting: CW node B

- A sends convert PR->CW to C
- C grants the conversion to CW for A
- C grants the waiting request for CW to B
- C sends granted message to B, but fails
  before it can send the granted message to A
- B receives the granted message from C

At this point:
- A believes it is converting PR->CW
- B believes it is holding a CW lock

The correct lock recovery steps in this example are:
- node D becomes the new master of R
- node A sends D its lkb, convert PR->CW
- node B sends D its lkb, granted CW
- D determins the correct lock state is:
  granted: CW node B
  granted: CW node A

The lkb sent by B is recreated without change,
but the lkb sent by A is changed because the
granted mode was not compatible.

Fixes to make this work correctly:

recover_convert_waiter: should not make any changes
to a converting lkb that is still waiting for a reply
message.  It was previously setting grmode to IV, which
is invalid state, so the lkb would not be handled
correctly by other code.

receive_rcom_lock_args: was checking the wrong lkb field
(wait_type instead of status) to determine if the lkb is
being converted, and in need of inspection for this special
recovery.  It was also setting grmode to IV in the lkb,
causing it to be mishandled by other code.
Now, this function just puts the lkb, directly as sent,
onto the convert queue of the resource being recovered,
and corrects it in recover_conversion() later, if needed.

recover_conversion: the job of this function is to detect
and correct lkb states for the special PR/CW conversions.
The new code now checks for recovered lkbs on the granted
queue with grmode PR or CW, and takes the real grmode from
that.  Then it looks for lkbs on the convert queue with an
incompatible grmode (i.e. grmode PR when the real grmode is
CW, or v.v.)  These converting lkbs need to be fixed.
They are fixed by temporarily setting their grmode to NL,
so that grmodes are not incompatible and won't confuse other
locking code.  The converting lkb will then be granted at
the end of recovery, replacing the temporary NL grmode.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>