kernel/fs/dlm/requestqueue.h, branch linux-2.6.25.y

dlm: use proper C for dlm/requestqueue stuff (and fix alignment bug)

2008-02-04T07:21:32Z

a) don't cast the pointer to dlm_header *, we use it as dlm_message * anyway. b) we copy the message into a queue element, then pass the pointer to copy to dlm_receive_message_saved(); declare it properly to make sure that we have the right alignment. Signed-off-by: Al Viro Signed-off-by: David Teigland

[DLM] block dlm_recv in recovery transition

2007-10-10T07:56:38Z

Introduce a per-lockspace rwsem that's held in read mode by dlm_recv threads while working in the dlm. This allows dlm_recv activity to be suspended when the lockspace transitions to, from and between recovery cycles. The specific bug prompting this change is one where an in-progress recovery cycle is aborted by a new recovery cycle. While dlm_recv was processing a recovery message, the recovery cycle was aborted and dlm_recoverd began cleaning up. dlm_recv decremented recover_locks_count on an rsb after dlm_recoverd had reset it to zero. This is fixed by suspending dlm_recv (taking write lock on the rwsem) before aborting the current recovery. The transitions to/from normal and recovery modes are simplified by using this new ability to block dlm_recv. The switch from normal to recovery mode means dlm_recv goes from processing locking messages, to saving them for later, and vice versa. Races are avoided by blocking dlm_recv when setting the flag that switches between modes. Signed-off-by: David Teigland Signed-off-by: Steven Whitehouse

[DLM] fix requestqueue race

2006-11-30T15:35:10Z

Red Hat BZ 211914 There's a race between dlm_recoverd (1) enabling locking and (2) clearing out the requestqueue, and dlm_recvd (1) checking if locking is enabled and (2) adding a message to the requestqueue. An order of recoverd(1), recvd(1), recvd(2), recoverd(2) will result in a message being left on the requestqueue. The fix is to have dlm_recvd check if dlm_recoverd has enabled locking after taking the mutex for the requestqueue and if it has processing the message instead of queueing it. Signed-off-by: David Teigland Signed-off-by: Steven Whitehouse

[DLM] The core of the DLM for GFS2/CLVM

2006-01-18T09:30:29Z

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: David Teigland Signed-off-by: Steve Whitehouse