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android_kernel_motorola_sm6225/fs/dlm/rcom.c
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

505 lines
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/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 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
** of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/
#include "dlm_internal.h"
#include "lockspace.h"
#include "member.h"
#include "lowcomms.h"
#include "midcomms.h"
#include "rcom.h"
#include "recover.h"
#include "dir.h"
#include "config.h"
#include "memory.h"
#include "lock.h"
#include "util.h"
static int rcom_response(struct dlm_ls *ls)
{
return test_bit(LSFL_RCOM_READY, &ls->ls_flags);
}
static int create_rcom(struct dlm_ls *ls, int to_nodeid, int type, int len,
struct dlm_rcom **rc_ret, struct dlm_mhandle **mh_ret)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
char *mb;
int mb_len = sizeof(struct dlm_rcom) + len;
mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, ls->ls_allocation, &mb);
if (!mh) {
log_print("create_rcom to %d type %d len %d ENOBUFS",
to_nodeid, type, len);
return -ENOBUFS;
}
memset(mb, 0, mb_len);
rc = (struct dlm_rcom *) mb;
rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
rc->rc_header.h_lockspace = ls->ls_global_id;
rc->rc_header.h_nodeid = dlm_our_nodeid();
rc->rc_header.h_length = mb_len;
rc->rc_header.h_cmd = DLM_RCOM;
rc->rc_type = type;
spin_lock(&ls->ls_recover_lock);
rc->rc_seq = ls->ls_recover_seq;
spin_unlock(&ls->ls_recover_lock);
*mh_ret = mh;
*rc_ret = rc;
return 0;
}
static void send_rcom(struct dlm_ls *ls, struct dlm_mhandle *mh,
struct dlm_rcom *rc)
{
dlm_rcom_out(rc);
dlm_lowcomms_commit_buffer(mh);
}
/* When replying to a status request, a node also sends back its
configuration values. The requesting node then checks that the remote
node is configured the same way as itself. */
static void make_config(struct dlm_ls *ls, struct rcom_config *rf)
{
rf->rf_lvblen = ls->ls_lvblen;
rf->rf_lsflags = ls->ls_exflags;
}
static int check_config(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
{
struct rcom_config *rf = (struct rcom_config *) rc->rc_buf;
if ((rc->rc_header.h_version & 0xFFFF0000) != DLM_HEADER_MAJOR) {
log_error(ls, "version mismatch: %x nodeid %d: %x",
DLM_HEADER_MAJOR | DLM_HEADER_MINOR, nodeid,
rc->rc_header.h_version);
return -EPROTO;
}
if (rf->rf_lvblen != ls->ls_lvblen ||
rf->rf_lsflags != ls->ls_exflags) {
log_error(ls, "config mismatch: %d,%x nodeid %d: %d,%x",
ls->ls_lvblen, ls->ls_exflags,
nodeid, rf->rf_lvblen, rf->rf_lsflags);
return -EPROTO;
}
return 0;
}
static void allow_sync_reply(struct dlm_ls *ls, uint64_t *new_seq)
{
spin_lock(&ls->ls_rcom_spin);
*new_seq = ++ls->ls_rcom_seq;
set_bit(LSFL_RCOM_WAIT, &ls->ls_flags);
spin_unlock(&ls->ls_rcom_spin);
}
static void disallow_sync_reply(struct dlm_ls *ls)
{
spin_lock(&ls->ls_rcom_spin);
clear_bit(LSFL_RCOM_WAIT, &ls->ls_flags);
clear_bit(LSFL_RCOM_READY, &ls->ls_flags);
spin_unlock(&ls->ls_rcom_spin);
}
int dlm_rcom_status(struct dlm_ls *ls, int nodeid)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
int error = 0;
ls->ls_recover_nodeid = nodeid;
if (nodeid == dlm_our_nodeid()) {
rc = (struct dlm_rcom *) ls->ls_recover_buf;
rc->rc_result = dlm_recover_status(ls);
goto out;
}
error = create_rcom(ls, nodeid, DLM_RCOM_STATUS, 0, &rc, &mh);
if (error)
goto out;
allow_sync_reply(ls, &rc->rc_id);
memset(ls->ls_recover_buf, 0, dlm_config.ci_buffer_size);
send_rcom(ls, mh, rc);
error = dlm_wait_function(ls, &rcom_response);
disallow_sync_reply(ls);
if (error)
goto out;
rc = (struct dlm_rcom *) ls->ls_recover_buf;
if (rc->rc_result == -ESRCH) {
/* we pretend the remote lockspace exists with 0 status */
log_debug(ls, "remote node %d not ready", nodeid);
rc->rc_result = 0;
} else
error = check_config(ls, rc, nodeid);
/* the caller looks at rc_result for the remote recovery status */
out:
return error;
}
static void receive_rcom_status(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
int error, nodeid = rc_in->rc_header.h_nodeid;
error = create_rcom(ls, nodeid, DLM_RCOM_STATUS_REPLY,
sizeof(struct rcom_config), &rc, &mh);
if (error)
return;
rc->rc_id = rc_in->rc_id;
rc->rc_seq_reply = rc_in->rc_seq;
rc->rc_result = dlm_recover_status(ls);
make_config(ls, (struct rcom_config *) rc->rc_buf);
send_rcom(ls, mh, rc);
}
static void receive_sync_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
spin_lock(&ls->ls_rcom_spin);
if (!test_bit(LSFL_RCOM_WAIT, &ls->ls_flags) ||
rc_in->rc_id != ls->ls_rcom_seq) {
log_debug(ls, "reject reply %d from %d seq %llx expect %llx",
rc_in->rc_type, rc_in->rc_header.h_nodeid,
(unsigned long long)rc_in->rc_id,
(unsigned long long)ls->ls_rcom_seq);
goto out;
}
memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
set_bit(LSFL_RCOM_READY, &ls->ls_flags);
clear_bit(LSFL_RCOM_WAIT, &ls->ls_flags);
wake_up(&ls->ls_wait_general);
out:
spin_unlock(&ls->ls_rcom_spin);
}
static void receive_rcom_status_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
receive_sync_reply(ls, rc_in);
}
int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
int error = 0, len = sizeof(struct dlm_rcom);
ls->ls_recover_nodeid = nodeid;
if (nodeid == dlm_our_nodeid()) {
dlm_copy_master_names(ls, last_name, last_len,
ls->ls_recover_buf + len,
dlm_config.ci_buffer_size - len, nodeid);
goto out;
}
error = create_rcom(ls, nodeid, DLM_RCOM_NAMES, last_len, &rc, &mh);
if (error)
goto out;
memcpy(rc->rc_buf, last_name, last_len);
allow_sync_reply(ls, &rc->rc_id);
memset(ls->ls_recover_buf, 0, dlm_config.ci_buffer_size);
send_rcom(ls, mh, rc);
error = dlm_wait_function(ls, &rcom_response);
disallow_sync_reply(ls);
out:
return error;
}
static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
int error, inlen, outlen, nodeid;
nodeid = rc_in->rc_header.h_nodeid;
inlen = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
outlen = dlm_config.ci_buffer_size - sizeof(struct dlm_rcom);
error = create_rcom(ls, nodeid, DLM_RCOM_NAMES_REPLY, outlen, &rc, &mh);
if (error)
return;
rc->rc_id = rc_in->rc_id;
rc->rc_seq_reply = rc_in->rc_seq;
dlm_copy_master_names(ls, rc_in->rc_buf, inlen, rc->rc_buf, outlen,
nodeid);
send_rcom(ls, mh, rc);
}
static void receive_rcom_names_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
receive_sync_reply(ls, rc_in);
}
int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
struct dlm_ls *ls = r->res_ls;
int error;
error = create_rcom(ls, dir_nodeid, DLM_RCOM_LOOKUP, r->res_length,
&rc, &mh);
if (error)
goto out;
memcpy(rc->rc_buf, r->res_name, r->res_length);
rc->rc_id = (unsigned long) r;
send_rcom(ls, mh, rc);
out:
return error;
}
static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
int error, ret_nodeid, nodeid = rc_in->rc_header.h_nodeid;
int len = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
error = create_rcom(ls, nodeid, DLM_RCOM_LOOKUP_REPLY, 0, &rc, &mh);
if (error)
return;
error = dlm_dir_lookup(ls, nodeid, rc_in->rc_buf, len, &ret_nodeid);
if (error)
ret_nodeid = error;
rc->rc_result = ret_nodeid;
rc->rc_id = rc_in->rc_id;
rc->rc_seq_reply = rc_in->rc_seq;
send_rcom(ls, mh, rc);
}
static void receive_rcom_lookup_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
dlm_recover_master_reply(ls, rc_in);
}
static void pack_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb,
struct rcom_lock *rl)
{
memset(rl, 0, sizeof(*rl));
rl->rl_ownpid = lkb->lkb_ownpid;
rl->rl_lkid = lkb->lkb_id;
rl->rl_exflags = lkb->lkb_exflags;
rl->rl_flags = lkb->lkb_flags;
rl->rl_lvbseq = lkb->lkb_lvbseq;
rl->rl_rqmode = lkb->lkb_rqmode;
rl->rl_grmode = lkb->lkb_grmode;
rl->rl_status = lkb->lkb_status;
rl->rl_wait_type = lkb->lkb_wait_type;
if (lkb->lkb_bastaddr)
rl->rl_asts |= AST_BAST;
if (lkb->lkb_astaddr)
rl->rl_asts |= AST_COMP;
rl->rl_namelen = r->res_length;
memcpy(rl->rl_name, r->res_name, r->res_length);
/* FIXME: might we have an lvb without DLM_LKF_VALBLK set ?
If so, receive_rcom_lock_args() won't take this copy. */
if (lkb->lkb_lvbptr)
memcpy(rl->rl_lvb, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
}
int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
struct dlm_ls *ls = r->res_ls;
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
struct rcom_lock *rl;
int error, len = sizeof(struct rcom_lock);
if (lkb->lkb_lvbptr)
len += ls->ls_lvblen;
error = create_rcom(ls, r->res_nodeid, DLM_RCOM_LOCK, len, &rc, &mh);
if (error)
goto out;
rl = (struct rcom_lock *) rc->rc_buf;
pack_rcom_lock(r, lkb, rl);
rc->rc_id = (unsigned long) r;
send_rcom(ls, mh, rc);
out:
return error;
}
static void receive_rcom_lock(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
struct dlm_rcom *rc;
struct dlm_mhandle *mh;
int error, nodeid = rc_in->rc_header.h_nodeid;
dlm_recover_master_copy(ls, rc_in);
error = create_rcom(ls, nodeid, DLM_RCOM_LOCK_REPLY,
sizeof(struct rcom_lock), &rc, &mh);
if (error)
return;
/* We send back the same rcom_lock struct we received, but
dlm_recover_master_copy() has filled in rl_remid and rl_result */
memcpy(rc->rc_buf, rc_in->rc_buf, sizeof(struct rcom_lock));
rc->rc_id = rc_in->rc_id;
rc->rc_seq_reply = rc_in->rc_seq;
send_rcom(ls, mh, rc);
}
static void receive_rcom_lock_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
dlm_recover_process_copy(ls, 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;
struct dlm_mhandle *mh;
char *mb;
int mb_len = sizeof(struct dlm_rcom) + sizeof(struct rcom_config);
mh = dlm_lowcomms_get_buffer(nodeid, mb_len, GFP_NOFS, &mb);
if (!mh)
return -ENOBUFS;
memset(mb, 0, mb_len);
rc = (struct dlm_rcom *) mb;
rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
rc->rc_header.h_lockspace = rc_in->rc_header.h_lockspace;
rc->rc_header.h_nodeid = dlm_our_nodeid();
rc->rc_header.h_length = mb_len;
rc->rc_header.h_cmd = DLM_RCOM;
rc->rc_type = DLM_RCOM_STATUS_REPLY;
rc->rc_id = rc_in->rc_id;
rc->rc_seq_reply = rc_in->rc_seq;
rc->rc_result = -ESRCH;
rf = (struct rcom_config *) rc->rc_buf;
rf->rf_lvblen = -1;
dlm_rcom_out(rc);
dlm_lowcomms_commit_buffer(mh);
return 0;
}
static int is_old_reply(struct dlm_ls *ls, struct dlm_rcom *rc)
{
uint64_t seq;
int rv = 0;
switch (rc->rc_type) {
case DLM_RCOM_STATUS_REPLY:
case DLM_RCOM_NAMES_REPLY:
case DLM_RCOM_LOOKUP_REPLY:
case DLM_RCOM_LOCK_REPLY:
spin_lock(&ls->ls_recover_lock);
seq = ls->ls_recover_seq;
spin_unlock(&ls->ls_recover_lock);
if (rc->rc_seq_reply != seq) {
log_debug(ls, "ignoring old reply %x from %d "
"seq_reply %llx expect %llx",
rc->rc_type, rc->rc_header.h_nodeid,
(unsigned long long)rc->rc_seq_reply,
(unsigned long long)seq);
rv = 1;
}
}
return rv;
}
/* Called by dlm_recv; corresponds to dlm_receive_message() but special
recovery-only comms are sent through here. */
void dlm_receive_rcom(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
{
if (dlm_recovery_stopped(ls) && (rc->rc_type != DLM_RCOM_STATUS)) {
log_debug(ls, "ignoring recovery message %x from %d",
rc->rc_type, nodeid);
goto out;
}
if (is_old_reply(ls, rc))
goto out;
switch (rc->rc_type) {
case DLM_RCOM_STATUS:
receive_rcom_status(ls, rc);
break;
case DLM_RCOM_NAMES:
receive_rcom_names(ls, rc);
break;
case DLM_RCOM_LOOKUP:
receive_rcom_lookup(ls, rc);
break;
case DLM_RCOM_LOCK:
receive_rcom_lock(ls, rc);
break;
case DLM_RCOM_STATUS_REPLY:
receive_rcom_status_reply(ls, rc);
break;
case DLM_RCOM_NAMES_REPLY:
receive_rcom_names_reply(ls, rc);
break;
case DLM_RCOM_LOOKUP_REPLY:
receive_rcom_lookup_reply(ls, rc);
break;
case DLM_RCOM_LOCK_REPLY:
receive_rcom_lock_reply(ls, rc);
break;
default:
DLM_ASSERT(0, printk("rc_type=%x\n", rc->rc_type););
}
out:
return;
}
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