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[DLM] block dlm_recv in recovery transition

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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>
This commit is contained in:
David Teigland
2007-09-27 15:53:38 -05:00
committed by Steven Whitehouse
parent b434eda6fd
commit c36258b592
11 changed files with 161 additions and 152 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
fs/dlm/rcom.c
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@@ -2,7 +2,7 @@
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2005 Red Hat, Inc. All rights reserved.
** 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
@@ -386,7 +386,10 @@ static void receive_rcom_lock_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
dlm_recover_process_copy(ls, rc_in);
}
static int send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
/* If the lockspace doesn't exist then still send a status message
back; it's possible that it just doesn't have its global_id yet. */
int dlm_send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
{
struct dlm_rcom *rc;
struct rcom_config *rf;
@@ -446,28 +449,11 @@ static int is_old_reply(struct dlm_ls *ls, struct dlm_rcom *rc)
return rv;
}
/* Called by dlm_recvd; corresponds to dlm_receive_message() but special
/* Called by dlm_recv; corresponds to dlm_receive_message() but special
recovery-only comms are sent through here. */
void dlm_receive_rcom(struct dlm_header *hd, int nodeid)
void dlm_receive_rcom(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
{
struct dlm_rcom *rc = (struct dlm_rcom *) hd;
struct dlm_ls *ls;
dlm_rcom_in(rc);
/* If the lockspace doesn't exist then still send a status message
back; it's possible that it just doesn't have its global_id yet. */
ls = dlm_find_lockspace_global(hd->h_lockspace);
if (!ls) {
log_print("lockspace %x from %d type %x not found",
hd->h_lockspace, nodeid, rc->rc_type);
if (rc->rc_type == DLM_RCOM_STATUS)
send_ls_not_ready(nodeid, rc);
return;
}
if (dlm_recovery_stopped(ls) && (rc->rc_type != DLM_RCOM_STATUS)) {
log_debug(ls, "ignoring recovery message %x from %d",
rc->rc_type, nodeid);
@@ -477,12 +463,6 @@ void dlm_receive_rcom(struct dlm_header *hd, int nodeid)
if (is_old_reply(ls, rc))
goto out;
if (nodeid != rc->rc_header.h_nodeid) {
log_error(ls, "bad rcom nodeid %d from %d",
rc->rc_header.h_nodeid, nodeid);
goto out;
}
switch (rc->rc_type) {
case DLM_RCOM_STATUS:
receive_rcom_status(ls, rc);
@@ -520,6 +500,6 @@ void dlm_receive_rcom(struct dlm_header *hd, int nodeid)
DLM_ASSERT(0, printk("rc_type=%x\n", rc->rc_type););
}
out:
dlm_put_lockspace(ls);
return;
}