A reply to a recovery message will often be received after the relevant
recovery sequence has aborted and the next recovery sequence has begun.
We need to ignore replies to these old messages from the previous
recovery.  There's already a way to do this for synchronous recovery
requests using the rc_id number, but not for async.

Each recovery sequence already has a locally unique sequence number
associated with it.  This patch adds a field to the rcom (recovery
message) structure where this recovery sequence number can be placed,
rc_seq.  When a node sends a reply to a recovery request, it copies the
rc_seq number it received into rc_seq_reply.  When the first node receives
the reply to its recovery message, it will check whether rc_seq_reply
matches the current recovery sequence number, ls_recover_seq, and if not
then it ignores the old reply.

An old, inadequate approach to filtering out old replies (checking if the
current stage of recovery has moved back to the start) has been removed
from two spots.

The protocol version number is changed to reflect the different rcom
structures.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

We often abort a recovery after sending a status request to a remote node.
We want to ignore any potential status reply we get from the remote node.
If we get one of these unwanted replies, we've often moved on to the next
recovery message and incremented the message sequence counter, so the
reply will be ignored due to the seq number.  In some cases, we've not
moved on to the next message so the seq number of the reply we want to
ignore is still correct, causing the reply to be accepted.  The next
recovery message will then mistake this old reply as a new one.

To fix this, we add the flag RCOM_WAIT to indicate when we can accept a
new reply.  We clear this flag if we abort recovery while waiting for a
reply.  Before the flag is set again (to allow new replies) we know that
any old replies will be rejected due to their sequence number.  We also
initialize the recovery-message sequence number to a random value when a
lockspace is first created.  This makes it clear when messages are being
rejected from an old instance of a lockspace that has since been
recreated.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The down-conversion optimization was resulting in the lkb flags being
cleared because the stub message reply had no flags value set.  Copy the
current flags into the stub message so they'll be copied back into the lkb
as part of processing the fake reply.  Also add an assertion to catch this
error more directly if it exists elsewhere.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

When recoveries are aborted by other recoveries we can get replies to
status or names requests that we've given up on.  This can cause problems
if we're making another request and receive an old reply.  Add a sequence
number to status/names requests and reject replies that don't match.  A
field already exists for the seq number that's used in other message
types.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

To aid debugging, it's useful to be able to see what nodeid the dlm is
waiting on for a message reply.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Display more information from debugfs, particularly locks waiting for
a master lookup or operations waiting for a remote reply.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This changes the way the dlm handles user locks.  The core dlm is now
aware of user locks so they can be dealt with more efficiently.  There is
no more dlm_device module which previously managed its own duplicate copy
of every user lock.
Signed-off-by: NPatrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

In dlm_grant_after_purge() we were holding a hash table read_lock while
calling put_rsb() which potentially removes the rsb from the hash table,
taking the same lock in write.  Fix this by flagging rsb's ahead of time
that have been purged.  Then iteratively read_lock the hash table, find a
flagged rsb, unlock, process rsb.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch removes support for range locking from the DLM
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteve Whitehouse <swhiteho@redhat.com>

This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalone lock manager independantly of either
of these two projects.

It implements VAX-style locking modes.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteve Whitehouse <swhiteho@redhat.com>