linux/fs/dlm/lock.h
David Teigland c36258b592 [DLM] block dlm_recv in recovery transition
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 <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10 08:56:38 +01:00

73 lines
2.7 KiB
C

/******************************************************************************
*******************************************************************************
**
** Copyright (C) 2005-2007 Red Hat, Inc. All rights reserved.
**
** This copyrighted material is made available to anyone wishing to use,
** modify, copy, or redistribute it subject to the terms and conditions
** of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/
#ifndef __LOCK_DOT_H__
#define __LOCK_DOT_H__
void dlm_print_rsb(struct dlm_rsb *r);
void dlm_dump_rsb(struct dlm_rsb *r);
void dlm_print_lkb(struct dlm_lkb *lkb);
void dlm_receive_message_saved(struct dlm_ls *ls, struct dlm_message *ms);
void dlm_receive_buffer(struct dlm_header *hd, int nodeid);
int dlm_modes_compat(int mode1, int mode2);
int dlm_find_rsb(struct dlm_ls *ls, char *name, int namelen,
unsigned int flags, struct dlm_rsb **r_ret);
void dlm_put_rsb(struct dlm_rsb *r);
void dlm_hold_rsb(struct dlm_rsb *r);
int dlm_put_lkb(struct dlm_lkb *lkb);
void dlm_scan_rsbs(struct dlm_ls *ls);
int dlm_lock_recovery_try(struct dlm_ls *ls);
void dlm_unlock_recovery(struct dlm_ls *ls);
void dlm_scan_timeout(struct dlm_ls *ls);
void dlm_adjust_timeouts(struct dlm_ls *ls);
int dlm_purge_locks(struct dlm_ls *ls);
void dlm_purge_mstcpy_locks(struct dlm_rsb *r);
void dlm_grant_after_purge(struct dlm_ls *ls);
int dlm_recover_waiters_post(struct dlm_ls *ls);
void dlm_recover_waiters_pre(struct dlm_ls *ls);
int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc);
int dlm_recover_process_copy(struct dlm_ls *ls, struct dlm_rcom *rc);
int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua, int mode,
uint32_t flags, void *name, unsigned int namelen,
unsigned long timeout_cs);
int dlm_user_convert(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
int mode, uint32_t flags, uint32_t lkid, char *lvb_in,
unsigned long timeout_cs);
int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
uint32_t flags, uint32_t lkid, char *lvb_in);
int dlm_user_cancel(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
uint32_t flags, uint32_t lkid);
int dlm_user_purge(struct dlm_ls *ls, struct dlm_user_proc *proc,
int nodeid, int pid);
int dlm_user_deadlock(struct dlm_ls *ls, uint32_t flags, uint32_t lkid);
void dlm_clear_proc_locks(struct dlm_ls *ls, struct dlm_user_proc *proc);
static inline int is_master(struct dlm_rsb *r)
{
return !r->res_nodeid;
}
static inline void lock_rsb(struct dlm_rsb *r)
{
mutex_lock(&r->res_mutex);
}
static inline void unlock_rsb(struct dlm_rsb *r)
{
mutex_unlock(&r->res_mutex);
}
#endif