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linux/fs/ocfs2/dlm/dlmmaster.c
Mark Fasheh 95c4f581d6 ocfs2: inline dlm_lockres_get() 
It's called on every lookup so this might help performance a bit.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-06-26 14:42:41 -07:00

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/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* dlmmod.c
*
* standalone DLM module
*
* Copyright (C) 2004 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/random.h>
#include <linux/blkdev.h>
#include <linux/socket.h>
#include <linux/inet.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include "cluster/heartbeat.h"
#include "cluster/nodemanager.h"
#include "cluster/tcp.h"
#include "dlmapi.h"
#include "dlmcommon.h"
#include "dlmdebug.h"
#include "dlmdomain.h"
#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
#include "cluster/masklog.h"
enum dlm_mle_type {
DLM_MLE_BLOCK,
DLM_MLE_MASTER,
DLM_MLE_MIGRATION
};
struct dlm_lock_name
{
u8 len;
u8 name[DLM_LOCKID_NAME_MAX];
};
struct dlm_master_list_entry
{
struct list_head list;
struct list_head hb_events;
struct dlm_ctxt *dlm;
spinlock_t spinlock;
wait_queue_head_t wq;
atomic_t woken;
struct kref mle_refs;
unsigned long maybe_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
unsigned long vote_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
unsigned long response_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
unsigned long node_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
u8 master;
u8 new_master;
enum dlm_mle_type type;
struct o2hb_callback_func mle_hb_up;
struct o2hb_callback_func mle_hb_down;
union {
struct dlm_lock_resource *res;
struct dlm_lock_name name;
} u;
};
static void dlm_mle_node_down(struct dlm_ctxt *dlm,
struct dlm_master_list_entry *mle,
struct o2nm_node *node,
int idx);
static void dlm_mle_node_up(struct dlm_ctxt *dlm,
struct dlm_master_list_entry *mle,
struct o2nm_node *node,
int idx);
static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
unsigned int namelen, void *nodemap,
u32 flags);
static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
struct dlm_master_list_entry *mle,
const char *name,
unsigned int namelen)
{
struct dlm_lock_resource *res;
if (dlm != mle->dlm)
return 0;
if (mle->type == DLM_MLE_BLOCK ||
mle->type == DLM_MLE_MIGRATION) {
if (namelen != mle->u.name.len ||
memcmp(name, mle->u.name.name, namelen)!=0)
return 0;
} else {
res = mle->u.res;
if (namelen != res->lockname.len ||
memcmp(res->lockname.name, name, namelen) != 0)
return 0;
}
return 1;
}
#if 0
/* Code here is included but defined out as it aids debugging */
void dlm_print_one_mle(struct dlm_master_list_entry *mle)
{
int i = 0, refs;
char *type;
char attached;
u8 master;
unsigned int namelen;
const char *name;
struct kref *k;
k = &mle->mle_refs;
if (mle->type == DLM_MLE_BLOCK)
type = "BLK";
else if (mle->type == DLM_MLE_MASTER)
type = "MAS";
else
type = "MIG";
refs = atomic_read(&k->refcount);
master = mle->master;
attached = (list_empty(&mle->hb_events) ? 'N' : 'Y');
if (mle->type != DLM_MLE_MASTER) {
namelen = mle->u.name.len;
name = mle->u.name.name;
} else {
namelen = mle->u.res->lockname.len;
name = mle->u.res->lockname.name;
}
mlog(ML_NOTICE, " #%3d: %3s %3d %3u %3u %c (%d)%.*s\n",
i, type, refs, master, mle->new_master, attached,
namelen, namelen, name);
}
static void dlm_dump_mles(struct dlm_ctxt *dlm)
{
struct dlm_master_list_entry *mle;
struct list_head *iter;
mlog(ML_NOTICE, "dumping all mles for domain %s:\n", dlm->name);
mlog(ML_NOTICE, " ####: type refs owner new events? lockname nodemap votemap respmap maybemap\n");
spin_lock(&dlm->master_lock);
list_for_each(iter, &dlm->master_list) {
mle = list_entry(iter, struct dlm_master_list_entry, list);
dlm_print_one_mle(mle);
}
spin_unlock(&dlm->master_lock);
}
int dlm_dump_all_mles(const char __user *data, unsigned int len)
{
struct list_head *iter;
struct dlm_ctxt *dlm;
spin_lock(&dlm_domain_lock);
list_for_each(iter, &dlm_domains) {
dlm = list_entry (iter, struct dlm_ctxt, list);
mlog(ML_NOTICE, "found dlm: %p, name=%s\n", dlm, dlm->name);
dlm_dump_mles(dlm);
}
spin_unlock(&dlm_domain_lock);
return len;
}
EXPORT_SYMBOL_GPL(dlm_dump_all_mles);
#endif /* 0 */
static kmem_cache_t *dlm_mle_cache = NULL;
static void dlm_mle_release(struct kref *kref);
static void dlm_init_mle(struct dlm_master_list_entry *mle,
enum dlm_mle_type type,
struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
const char *name,
unsigned int namelen);
static void dlm_put_mle(struct dlm_master_list_entry *mle);
static void __dlm_put_mle(struct dlm_master_list_entry *mle);
static int dlm_find_mle(struct dlm_ctxt *dlm,
struct dlm_master_list_entry **mle,
char *name, unsigned int namelen);
static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to);
static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_master_list_entry *mle,
int *blocked);
static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_master_list_entry *mle,
int blocked);
static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_master_list_entry *mle,
struct dlm_master_list_entry **oldmle,
const char *name, unsigned int namelen,
u8 new_master, u8 master);
static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res);
static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res);
static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
u8 target);
static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res);
int dlm_is_host_down(int errno)
{
switch (errno) {
case -EBADF:
case -ECONNREFUSED:
case -ENOTCONN:
case -ECONNRESET:
case -EPIPE:
case -EHOSTDOWN:
case -EHOSTUNREACH:
case -ETIMEDOUT:
case -ECONNABORTED:
case -ENETDOWN:
case -ENETUNREACH:
case -ENETRESET:
case -ESHUTDOWN:
case -ENOPROTOOPT:
case -EINVAL: /* if returned from our tcp code,
this means there is no socket */
return 1;
}
return 0;
}
/*
* MASTER LIST FUNCTIONS
*/
/*
* regarding master list entries and heartbeat callbacks:
*
* in order to avoid sleeping and allocation that occurs in
* heartbeat, master list entries are simply attached to the
* dlm's established heartbeat callbacks. the mle is attached
* when it is created, and since the dlm->spinlock is held at
* that time, any heartbeat event will be properly discovered
* by the mle. the mle needs to be detached from the
* dlm->mle_hb_events list as soon as heartbeat events are no
* longer useful to the mle, and before the mle is freed.
*
* as a general rule, heartbeat events are no longer needed by
* the mle once an "answer" regarding the lock master has been
* received.
*/
static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
struct dlm_master_list_entry *mle)
{
assert_spin_locked(&dlm->spinlock);
list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
}
static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
struct dlm_master_list_entry *mle)
{
if (!list_empty(&mle->hb_events))
list_del_init(&mle->hb_events);
}
static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
struct dlm_master_list_entry *mle)
{
spin_lock(&dlm->spinlock);
__dlm_mle_detach_hb_events(dlm, mle);
spin_unlock(&dlm->spinlock);
}
/* remove from list and free */
static void __dlm_put_mle(struct dlm_master_list_entry *mle)
{
struct dlm_ctxt *dlm;
dlm = mle->dlm;
assert_spin_locked(&dlm->spinlock);
assert_spin_locked(&dlm->master_lock);
BUG_ON(!atomic_read(&mle->mle_refs.refcount));
kref_put(&mle->mle_refs, dlm_mle_release);
}
/* must not have any spinlocks coming in */
static void dlm_put_mle(struct dlm_master_list_entry *mle)
{
struct dlm_ctxt *dlm;
dlm = mle->dlm;
spin_lock(&dlm->spinlock);
spin_lock(&dlm->master_lock);
__dlm_put_mle(mle);
spin_unlock(&dlm->master_lock);
spin_unlock(&dlm->spinlock);
}
static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
{
kref_get(&mle->mle_refs);
}
static void dlm_init_mle(struct dlm_master_list_entry *mle,
enum dlm_mle_type type,
struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
const char *name,
unsigned int namelen)
{
assert_spin_locked(&dlm->spinlock);
mle->dlm = dlm;
mle->type = type;
INIT_LIST_HEAD(&mle->list);
INIT_LIST_HEAD(&mle->hb_events);
memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
spin_lock_init(&mle->spinlock);
init_waitqueue_head(&mle->wq);
atomic_set(&mle->woken, 0);
kref_init(&mle->mle_refs);
memset(mle->response_map, 0, sizeof(mle->response_map));
mle->master = O2NM_MAX_NODES;
mle->new_master = O2NM_MAX_NODES;
if (mle->type == DLM_MLE_MASTER) {
BUG_ON(!res);
mle->u.res = res;
} else if (mle->type == DLM_MLE_BLOCK) {
BUG_ON(!name);
memcpy(mle->u.name.name, name, namelen);
mle->u.name.len = namelen;
} else /* DLM_MLE_MIGRATION */ {
BUG_ON(!name);
memcpy(mle->u.name.name, name, namelen);
mle->u.name.len = namelen;
}
/* copy off the node_map and register hb callbacks on our copy */
memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
clear_bit(dlm->node_num, mle->vote_map);
clear_bit(dlm->node_num, mle->node_map);
/* attach the mle to the domain node up/down events */
__dlm_mle_attach_hb_events(dlm, mle);
}
/* returns 1 if found, 0 if not */
static int dlm_find_mle(struct dlm_ctxt *dlm,
struct dlm_master_list_entry **mle,
char *name, unsigned int namelen)
{
struct dlm_master_list_entry *tmpmle;
struct list_head *iter;
assert_spin_locked(&dlm->master_lock);
list_for_each(iter, &dlm->master_list) {
tmpmle = list_entry(iter, struct dlm_master_list_entry, list);
if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
continue;
dlm_get_mle(tmpmle);
*mle = tmpmle;
return 1;
}
return 0;
}
void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
{
struct dlm_master_list_entry *mle;
struct list_head *iter;
assert_spin_locked(&dlm->spinlock);
list_for_each(iter, &dlm->mle_hb_events) {
mle = list_entry(iter, struct dlm_master_list_entry,
hb_events);
if (node_up)
dlm_mle_node_up(dlm, mle, NULL, idx);
else
dlm_mle_node_down(dlm, mle, NULL, idx);
}
}
static void dlm_mle_node_down(struct dlm_ctxt *dlm,
struct dlm_master_list_entry *mle,
struct o2nm_node *node, int idx)
{
spin_lock(&mle->spinlock);
if (!test_bit(idx, mle->node_map))
mlog(0, "node %u already removed from nodemap!\n", idx);
else
clear_bit(idx, mle->node_map);
spin_unlock(&mle->spinlock);
}
static void dlm_mle_node_up(struct dlm_ctxt *dlm,
struct dlm_master_list_entry *mle,
struct o2nm_node *node, int idx)
{
spin_lock(&mle->spinlock);
if (test_bit(idx, mle->node_map))
mlog(0, "node %u already in node map!\n", idx);
else
set_bit(idx, mle->node_map);
spin_unlock(&mle->spinlock);
}
int dlm_init_mle_cache(void)
{
dlm_mle_cache = kmem_cache_create("dlm_mle_cache",
sizeof(struct dlm_master_list_entry),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if (dlm_mle_cache == NULL)
return -ENOMEM;
return 0;
}
void dlm_destroy_mle_cache(void)
{
if (dlm_mle_cache)
kmem_cache_destroy(dlm_mle_cache);
}
static void dlm_mle_release(struct kref *kref)
{
struct dlm_master_list_entry *mle;
struct dlm_ctxt *dlm;
mlog_entry_void();
mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
dlm = mle->dlm;
if (mle->type != DLM_MLE_MASTER) {
mlog(0, "calling mle_release for %.*s, type %d\n",
mle->u.name.len, mle->u.name.name, mle->type);
} else {
mlog(0, "calling mle_release for %.*s, type %d\n",
mle->u.res->lockname.len,
mle->u.res->lockname.name, mle->type);
}
assert_spin_locked(&dlm->spinlock);
assert_spin_locked(&dlm->master_lock);
/* remove from list if not already */
if (!list_empty(&mle->list))
list_del_init(&mle->list);
/* detach the mle from the domain node up/down events */
__dlm_mle_detach_hb_events(dlm, mle);
/* NOTE: kfree under spinlock here.
* if this is bad, we can move this to a freelist. */
kmem_cache_free(dlm_mle_cache, mle);
}
/*
* LOCK RESOURCE FUNCTIONS
*/
static void dlm_set_lockres_owner(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
u8 owner)
{
assert_spin_locked(&res->spinlock);
mlog_entry("%.*s, %u\n", res->lockname.len, res->lockname.name, owner);
if (owner == dlm->node_num)
atomic_inc(&dlm->local_resources);
else if (owner == DLM_LOCK_RES_OWNER_UNKNOWN)
atomic_inc(&dlm->unknown_resources);
else
atomic_inc(&dlm->remote_resources);
res->owner = owner;
}
void dlm_change_lockres_owner(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res, u8 owner)
{
assert_spin_locked(&res->spinlock);
if (owner == res->owner)
return;
if (res->owner == dlm->node_num)
atomic_dec(&dlm->local_resources);
else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN)
atomic_dec(&dlm->unknown_resources);
else
atomic_dec(&dlm->remote_resources);
dlm_set_lockres_owner(dlm, res, owner);
}
static void dlm_lockres_release(struct kref *kref)
{
struct dlm_lock_resource *res;
res = container_of(kref, struct dlm_lock_resource, refs);
/* This should not happen -- all lockres' have a name
* associated with them at init time. */
BUG_ON(!res->lockname.name);
mlog(0, "destroying lockres %.*s\n", res->lockname.len,
res->lockname.name);
/* By the time we're ready to blow this guy away, we shouldn't
* be on any lists. */
BUG_ON(!hlist_unhashed(&res->hash_node));
BUG_ON(!list_empty(&res->granted));
BUG_ON(!list_empty(&res->converting));
BUG_ON(!list_empty(&res->blocked));
BUG_ON(!list_empty(&res->dirty));
BUG_ON(!list_empty(&res->recovering));
BUG_ON(!list_empty(&res->purge));
kfree(res->lockname.name);
kfree(res);
}
void dlm_lockres_put(struct dlm_lock_resource *res)
{
kref_put(&res->refs, dlm_lockres_release);
}
static void dlm_init_lockres(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
const char *name, unsigned int namelen)
{
char *qname;
/* If we memset here, we lose our reference to the kmalloc'd
* res->lockname.name, so be sure to init every field
* correctly! */
qname = (char *) res->lockname.name;
memcpy(qname, name, namelen);
res->lockname.len = namelen;
res->lockname.hash = dlm_lockid_hash(name, namelen);
init_waitqueue_head(&res->wq);
spin_lock_init(&res->spinlock);
INIT_HLIST_NODE(&res->hash_node);
INIT_LIST_HEAD(&res->granted);
INIT_LIST_HEAD(&res->converting);
INIT_LIST_HEAD(&res->blocked);
INIT_LIST_HEAD(&res->dirty);
INIT_LIST_HEAD(&res->recovering);
INIT_LIST_HEAD(&res->purge);
atomic_set(&res->asts_reserved, 0);
res->migration_pending = 0;
kref_init(&res->refs);
/* just for consistency */
spin_lock(&res->spinlock);
dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
spin_unlock(&res->spinlock);
res->state = DLM_LOCK_RES_IN_PROGRESS;
res->last_used = 0;
memset(res->lvb, 0, DLM_LVB_LEN);
}
struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
const char *name,
unsigned int namelen)
{
struct dlm_lock_resource *res;
res = kmalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL);
if (!res)
return NULL;
res->lockname.name = kmalloc(namelen, GFP_KERNEL);
if (!res->lockname.name) {
kfree(res);
return NULL;
}
dlm_init_lockres(dlm, res, name, namelen);
return res;
}
/*
* lookup a lock resource by name.
* may already exist in the hashtable.
* lockid is null terminated
*
* if not, allocate enough for the lockres and for
* the temporary structure used in doing the mastering.
*
* also, do a lookup in the dlm->master_list to see
* if another node has begun mastering the same lock.
* if so, there should be a block entry in there
* for this name, and we should *not* attempt to master
* the lock here. need to wait around for that node
* to assert_master (or die).
*
*/
struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
const char *lockid,
int flags)
{
struct dlm_lock_resource *tmpres=NULL, *res=NULL;
struct dlm_master_list_entry *mle = NULL;
struct dlm_master_list_entry *alloc_mle = NULL;
int blocked = 0;
int ret, nodenum;
struct dlm_node_iter iter;
unsigned int namelen, hash;
int tries = 0;
int bit, wait_on_recovery = 0;
BUG_ON(!lockid);
namelen = strlen(lockid);
hash = dlm_lockid_hash(lockid, namelen);
mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
lookup:
spin_lock(&dlm->spinlock);
tmpres = __dlm_lookup_lockres(dlm, lockid, namelen, hash);
if (tmpres) {
spin_unlock(&dlm->spinlock);
mlog(0, "found in hash!\n");
if (res)
dlm_lockres_put(res);
res = tmpres;
goto leave;
}
if (!res) {
spin_unlock(&dlm->spinlock);
mlog(0, "allocating a new resource\n");
/* nothing found and we need to allocate one. */
alloc_mle = (struct dlm_master_list_entry *)
kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
if (!alloc_mle)
goto leave;
res = dlm_new_lockres(dlm, lockid, namelen);
if (!res)
goto leave;
goto lookup;
}
mlog(0, "no lockres found, allocated our own: %p\n", res);
if (flags & LKM_LOCAL) {
/* caller knows it's safe to assume it's not mastered elsewhere
* DONE! return right away */
spin_lock(&res->spinlock);
dlm_change_lockres_owner(dlm, res, dlm->node_num);
__dlm_insert_lockres(dlm, res);
spin_unlock(&res->spinlock);
spin_unlock(&dlm->spinlock);
/* lockres still marked IN_PROGRESS */
goto wake_waiters;
}
/* check master list to see if another node has started mastering it */
spin_lock(&dlm->master_lock);
/* if we found a block, wait for lock to be mastered by another node */
blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
if (blocked) {
if (mle->type == DLM_MLE_MASTER) {
mlog(ML_ERROR, "master entry for nonexistent lock!\n");
BUG();
} else if (mle->type == DLM_MLE_MIGRATION) {
/* migration is in progress! */
/* the good news is that we now know the
* "current" master (mle->master). */
spin_unlock(&dlm->master_lock);
assert_spin_locked(&dlm->spinlock);
/* set the lockres owner and hash it */
spin_lock(&res->spinlock);
dlm_set_lockres_owner(dlm, res, mle->master);
__dlm_insert_lockres(dlm, res);
spin_unlock(&res->spinlock);
spin_unlock(&dlm->spinlock);
/* master is known, detach */
dlm_mle_detach_hb_events(dlm, mle);
dlm_put_mle(mle);
mle = NULL;
goto wake_waiters;
}
} else {
/* go ahead and try to master lock on this node */
mle = alloc_mle;
/* make sure this does not get freed below */
alloc_mle = NULL;
dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
set_bit(dlm->node_num, mle->maybe_map);
list_add(&mle->list, &dlm->master_list);
/* still holding the dlm spinlock, check the recovery map
* to see if there are any nodes that still need to be
* considered. these will not appear in the mle nodemap
* but they might own this lockres. wait on them. */
bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
if (bit < O2NM_MAX_NODES) {
mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
"recover before lock mastery can begin\n",
dlm->name, namelen, (char *)lockid, bit);
wait_on_recovery = 1;
}
}
/* at this point there is either a DLM_MLE_BLOCK or a
* DLM_MLE_MASTER on the master list, so it's safe to add the
* lockres to the hashtable. anyone who finds the lock will
* still have to wait on the IN_PROGRESS. */
/* finally add the lockres to its hash bucket */
__dlm_insert_lockres(dlm, res);
/* get an extra ref on the mle in case this is a BLOCK
* if so, the creator of the BLOCK may try to put the last
* ref at this time in the assert master handler, so we
* need an extra one to keep from a bad ptr deref. */
dlm_get_mle(mle);
spin_unlock(&dlm->master_lock);
spin_unlock(&dlm->spinlock);
while (wait_on_recovery) {
/* any cluster changes that occurred after dropping the
* dlm spinlock would be detectable be a change on the mle,
* so we only need to clear out the recovery map once. */
if (dlm_is_recovery_lock(lockid, namelen)) {
mlog(ML_NOTICE, "%s: recovery map is not empty, but "
"must master $RECOVERY lock now\n", dlm->name);
if (!dlm_pre_master_reco_lockres(dlm, res))
wait_on_recovery = 0;
else {
mlog(0, "%s: waiting 500ms for heartbeat state "
"change\n", dlm->name);
msleep(500);
}
continue;
}
dlm_kick_recovery_thread(dlm);
msleep(100);
dlm_wait_for_recovery(dlm);
spin_lock(&dlm->spinlock);
bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
if (bit < O2NM_MAX_NODES) {
mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
"recover before lock mastery can begin\n",
dlm->name, namelen, (char *)lockid, bit);
wait_on_recovery = 1;
} else
wait_on_recovery = 0;
spin_unlock(&dlm->spinlock);
}
/* must wait for lock to be mastered elsewhere */
if (blocked)
goto wait;
redo_request:
ret = -EINVAL;
dlm_node_iter_init(mle->vote_map, &iter);
while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
ret = dlm_do_master_request(mle, nodenum);
if (ret < 0)
mlog_errno(ret);
if (mle->master != O2NM_MAX_NODES) {
/* found a master ! */
if (mle->master <= nodenum)
break;
/* if our master request has not reached the master
* yet, keep going until it does. this is how the
* master will know that asserts are needed back to
* the lower nodes. */
mlog(0, "%s:%.*s: requests only up to %u but master "
"is %u, keep going\n", dlm->name, namelen,
lockid, nodenum, mle->master);
}
}
wait:
/* keep going until the response map includes all nodes */
ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
if (ret < 0) {
mlog(0, "%s:%.*s: node map changed, redo the "
"master request now, blocked=%d\n",
dlm->name, res->lockname.len,
res->lockname.name, blocked);
if (++tries > 20) {
mlog(ML_ERROR, "%s:%.*s: spinning on "
"dlm_wait_for_lock_mastery, blocked=%d\n",
dlm->name, res->lockname.len,
res->lockname.name, blocked);
dlm_print_one_lock_resource(res);
/* dlm_print_one_mle(mle); */
tries = 0;
}
goto redo_request;
}
mlog(0, "lockres mastered by %u\n", res->owner);
/* make sure we never continue without this */
BUG_ON(res->owner == O2NM_MAX_NODES);
/* master is known, detach if not already detached */
dlm_mle_detach_hb_events(dlm, mle);
dlm_put_mle(mle);
/* put the extra ref */
dlm_put_mle(mle);
wake_waiters:
spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
spin_unlock(&res->spinlock);
wake_up(&res->wq);
leave:
/* need to free the unused mle */
if (alloc_mle)
kmem_cache_free(dlm_mle_cache, alloc_mle);
return res;
}
#define DLM_MASTERY_TIMEOUT_MS 5000
static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_master_list_entry *mle,
int *blocked)
{
u8 m;
int ret, bit;
int map_changed, voting_done;
int assert, sleep;
recheck:
ret = 0;
assert = 0;
/* check if another node has already become the owner */
spin_lock(&res->spinlock);
if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
res->lockname.len, res->lockname.name, res->owner);
spin_unlock(&res->spinlock);
/* this will cause the master to re-assert across
* the whole cluster, freeing up mles */
ret = dlm_do_master_request(mle, res->owner);
if (ret < 0) {
/* give recovery a chance to run */
mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
msleep(500);
goto recheck;
}
ret = 0;
goto leave;
}
spin_unlock(&res->spinlock);
spin_lock(&mle->spinlock);
m = mle->master;
map_changed = (memcmp(mle->vote_map, mle->node_map,
sizeof(mle->vote_map)) != 0);
voting_done = (memcmp(mle->vote_map, mle->response_map,
sizeof(mle->vote_map)) == 0);
/* restart if we hit any errors */
if (map_changed) {
int b;
mlog(0, "%s: %.*s: node map changed, restarting\n",
dlm->name, res->lockname.len, res->lockname.name);
ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
b = (mle->type == DLM_MLE_BLOCK);
if ((*blocked && !b) || (!*blocked && b)) {
mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
dlm->name, res->lockname.len, res->lockname.name,
*blocked, b);
*blocked = b;
}
spin_unlock(&mle->spinlock);
if (ret < 0) {
mlog_errno(ret);
goto leave;
}
mlog(0, "%s:%.*s: restart lock mastery succeeded, "
"rechecking now\n", dlm->name, res->lockname.len,
res->lockname.name);
goto recheck;
}
if (m != O2NM_MAX_NODES) {
/* another node has done an assert!
* all done! */
sleep = 0;
} else {
sleep = 1;
/* have all nodes responded? */
if (voting_done && !*blocked) {
bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
if (dlm->node_num <= bit) {
/* my node number is lowest.
* now tell other nodes that I am
* mastering this. */
mle->master = dlm->node_num;
assert = 1;
sleep = 0;
}
/* if voting is done, but we have not received
* an assert master yet, we must sleep */
}
}
spin_unlock(&mle->spinlock);
/* sleep if we haven't finished voting yet */
if (sleep) {
unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
/*
if (atomic_read(&mle->mle_refs.refcount) < 2)
mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
atomic_read(&mle->mle_refs.refcount),
res->lockname.len, res->lockname.name);
*/
atomic_set(&mle->woken, 0);
(void)wait_event_timeout(mle->wq,
(atomic_read(&mle->woken) == 1),
timeo);
if (res->owner == O2NM_MAX_NODES) {
mlog(0, "waiting again\n");
goto recheck;
}
mlog(0, "done waiting, master is %u\n", res->owner);
ret = 0;
goto leave;
}
ret = 0; /* done */
if (assert) {
m = dlm->node_num;
mlog(0, "about to master %.*s here, this=%u\n",
res->lockname.len, res->lockname.name, m);
ret = dlm_do_assert_master(dlm, res->lockname.name,
res->lockname.len, mle->vote_map, 0);
if (ret) {
/* This is a failure in the network path,
* not in the response to the assert_master
* (any nonzero response is a BUG on this node).
* Most likely a socket just got disconnected
* due to node death. */
mlog_errno(ret);
}
/* no longer need to restart lock mastery.
* all living nodes have been contacted. */
ret = 0;
}
/* set the lockres owner */
spin_lock(&res->spinlock);
dlm_change_lockres_owner(dlm, res, m);
spin_unlock(&res->spinlock);
leave:
return ret;
}
struct dlm_bitmap_diff_iter
{
int curnode;
unsigned long *orig_bm;
unsigned long *cur_bm;
unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
};
enum dlm_node_state_change
{
NODE_DOWN = -1,
NODE_NO_CHANGE = 0,
NODE_UP
};
static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
unsigned long *orig_bm,
unsigned long *cur_bm)
{
unsigned long p1, p2;
int i;
iter->curnode = -1;
iter->orig_bm = orig_bm;
iter->cur_bm = cur_bm;
for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
p1 = *(iter->orig_bm + i);
p2 = *(iter->cur_bm + i);
iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
}
}
static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
enum dlm_node_state_change *state)
{
int bit;
if (iter->curnode >= O2NM_MAX_NODES)
return -ENOENT;
bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
iter->curnode+1);
if (bit >= O2NM_MAX_NODES) {
iter->curnode = O2NM_MAX_NODES;
return -ENOENT;
}
/* if it was there in the original then this node died */
if (test_bit(bit, iter->orig_bm))
*state = NODE_DOWN;
else
*state = NODE_UP;
iter->curnode = bit;
return bit;
}
static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_master_list_entry *mle,
int blocked)
{
struct dlm_bitmap_diff_iter bdi;
enum dlm_node_state_change sc;
int node;
int ret = 0;
mlog(0, "something happened such that the "
"master process may need to be restarted!\n");
assert_spin_locked(&mle->spinlock);
dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
node = dlm_bitmap_diff_iter_next(&bdi, &sc);
while (node >= 0) {
if (sc == NODE_UP) {
/* a node came up. clear any old vote from
* the response map and set it in the vote map
* then restart the mastery. */
mlog(ML_NOTICE, "node %d up while restarting\n", node);
/* redo the master request, but only for the new node */
mlog(0, "sending request to new node\n");
clear_bit(node, mle->response_map);
set_bit(node, mle->vote_map);
} else {
mlog(ML_ERROR, "node down! %d\n", node);
/* if the node wasn't involved in mastery skip it,
* but clear it out from the maps so that it will
* not affect mastery of this lockres */
clear_bit(node, mle->response_map);
clear_bit(node, mle->vote_map);
if (!test_bit(node, mle->maybe_map))
goto next;
/* if we're already blocked on lock mastery, and the
* dead node wasn't the expected master, or there is
* another node in the maybe_map, keep waiting */
if (blocked) {
int lowest = find_next_bit(mle->maybe_map,
O2NM_MAX_NODES, 0);
/* act like it was never there */
clear_bit(node, mle->maybe_map);
if (node != lowest)
goto next;
mlog(ML_ERROR, "expected master %u died while "
"this node was blocked waiting on it!\n",
node);
lowest = find_next_bit(mle->maybe_map,
O2NM_MAX_NODES,
lowest+1);
if (lowest < O2NM_MAX_NODES) {
mlog(0, "still blocked. waiting "
"on %u now\n", lowest);
goto next;
}
/* mle is an MLE_BLOCK, but there is now
* nothing left to block on. we need to return
* all the way back out and try again with
* an MLE_MASTER. dlm_do_local_recovery_cleanup
* has already run, so the mle refcount is ok */
mlog(0, "no longer blocking. we can "
"try to master this here\n");
mle->type = DLM_MLE_MASTER;
memset(mle->maybe_map, 0,
sizeof(mle->maybe_map));
memset(mle->response_map, 0,
sizeof(mle->maybe_map));
memcpy(mle->vote_map, mle->node_map,
sizeof(mle->node_map));
mle->u.res = res;
set_bit(dlm->node_num, mle->maybe_map);
ret = -EAGAIN;
goto next;
}
clear_bit(node, mle->maybe_map);
if (node > dlm->node_num)
goto next;
mlog(0, "dead node in map!\n");
/* yuck. go back and re-contact all nodes
* in the vote_map, removing this node. */
memset(mle->response_map, 0,
sizeof(mle->response_map));
}
ret = -EAGAIN;
next:
node = dlm_bitmap_diff_iter_next(&bdi, &sc);
}
return ret;
}
/*
* DLM_MASTER_REQUEST_MSG
*
* returns: 0 on success,
* -errno on a network error
*
* on error, the caller should assume the target node is "dead"
*
*/
static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to)
{
struct dlm_ctxt *dlm = mle->dlm;
struct dlm_master_request request;
int ret, response=0, resend;
memset(&request, 0, sizeof(request));
request.node_idx = dlm->node_num;
BUG_ON(mle->type == DLM_MLE_MIGRATION);
if (mle->type != DLM_MLE_MASTER) {
request.namelen = mle->u.name.len;
memcpy(request.name, mle->u.name.name, request.namelen);
} else {
request.namelen = mle->u.res->lockname.len;
memcpy(request.name, mle->u.res->lockname.name,
request.namelen);
}
again:
ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
sizeof(request), to, &response);
if (ret < 0) {
if (ret == -ESRCH) {
/* should never happen */
mlog(ML_ERROR, "TCP stack not ready!\n");
BUG();
} else if (ret == -EINVAL) {
mlog(ML_ERROR, "bad args passed to o2net!\n");
BUG();
} else if (ret == -ENOMEM) {
mlog(ML_ERROR, "out of memory while trying to send "
"network message! retrying\n");
/* this is totally crude */
msleep(50);
goto again;
} else if (!dlm_is_host_down(ret)) {
/* not a network error. bad. */
mlog_errno(ret);
mlog(ML_ERROR, "unhandled error!");
BUG();
}
/* all other errors should be network errors,
* and likely indicate node death */
mlog(ML_ERROR, "link to %d went down!\n", to);
goto out;
}
ret = 0;
resend = 0;
spin_lock(&mle->spinlock);
switch (response) {
case DLM_MASTER_RESP_YES:
set_bit(to, mle->response_map);
mlog(0, "node %u is the master, response=YES\n", to);
mle->master = to;
break;
case DLM_MASTER_RESP_NO:
mlog(0, "node %u not master, response=NO\n", to);
set_bit(to, mle->response_map);
break;
case DLM_MASTER_RESP_MAYBE:
mlog(0, "node %u not master, response=MAYBE\n", to);
set_bit(to, mle->response_map);
set_bit(to, mle->maybe_map);
break;
case DLM_MASTER_RESP_ERROR:
mlog(0, "node %u hit an error, resending\n", to);
resend = 1;
response = 0;
break;
default:
mlog(ML_ERROR, "bad response! %u\n", response);
BUG();
}
spin_unlock(&mle->spinlock);
if (resend) {
/* this is also totally crude */
msleep(50);
goto again;
}
out:
return ret;
}
/*
* locks that can be taken here:
* dlm->spinlock
* res->spinlock
* mle->spinlock
* dlm->master_list
*
* if possible, TRIM THIS DOWN!!!
*/
int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data)
{
u8 response = DLM_MASTER_RESP_MAYBE;
struct dlm_ctxt *dlm = data;
struct dlm_lock_resource *res = NULL;
struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
char *name;
unsigned int namelen, hash;
int found, ret;
int set_maybe;
int dispatch_assert = 0;
if (!dlm_grab(dlm))
return DLM_MASTER_RESP_NO;
if (!dlm_domain_fully_joined(dlm)) {
response = DLM_MASTER_RESP_NO;
goto send_response;
}
name = request->name;
namelen = request->namelen;
hash = dlm_lockid_hash(name, namelen);
if (namelen > DLM_LOCKID_NAME_MAX) {
response = DLM_IVBUFLEN;
goto send_response;
}
way_up_top:
spin_lock(&dlm->spinlock);
res = __dlm_lookup_lockres(dlm, name, namelen, hash);
if (res) {
spin_unlock(&dlm->spinlock);
/* take care of the easy cases up front */
spin_lock(&res->spinlock);
if (res->state & DLM_LOCK_RES_RECOVERING) {
spin_unlock(&res->spinlock);
mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
"being recovered\n");
response = DLM_MASTER_RESP_ERROR;
if (mle)
kmem_cache_free(dlm_mle_cache, mle);
goto send_response;
}
if (res->owner == dlm->node_num) {
spin_unlock(&res->spinlock);
// mlog(0, "this node is the master\n");
response = DLM_MASTER_RESP_YES;
if (mle)
kmem_cache_free(dlm_mle_cache, mle);
/* this node is the owner.
* there is some extra work that needs to
* happen now. the requesting node has
* caused all nodes up to this one to
* create mles. this node now needs to
* go back and clean those up. */
dispatch_assert = 1;
goto send_response;
} else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
spin_unlock(&res->spinlock);
// mlog(0, "node %u is the master\n", res->owner);
response = DLM_MASTER_RESP_NO;
if (mle)
kmem_cache_free(dlm_mle_cache, mle);
goto send_response;
}
/* ok, there is no owner. either this node is
* being blocked, or it is actively trying to
* master this lock. */
if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
mlog(ML_ERROR, "lock with no owner should be "
"in-progress!\n");
BUG();
}
// mlog(0, "lockres is in progress...\n");
spin_lock(&dlm->master_lock);
found = dlm_find_mle(dlm, &tmpmle, name, namelen);
if (!found) {
mlog(ML_ERROR, "no mle found for this lock!\n");
BUG();
}
set_maybe = 1;
spin_lock(&tmpmle->spinlock);
if (tmpmle->type == DLM_MLE_BLOCK) {
// mlog(0, "this node is waiting for "
// "lockres to be mastered\n");
response = DLM_MASTER_RESP_NO;
} else if (tmpmle->type == DLM_MLE_MIGRATION) {
mlog(0, "node %u is master, but trying to migrate to "
"node %u.\n", tmpmle->master, tmpmle->new_master);
if (tmpmle->master == dlm->node_num) {
response = DLM_MASTER_RESP_YES;
mlog(ML_ERROR, "no owner on lockres, but this "
"node is trying to migrate it to %u?!\n",
tmpmle->new_master);
BUG();
} else {
/* the real master can respond on its own */
response = DLM_MASTER_RESP_NO;
}
} else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
set_maybe = 0;
if (tmpmle->master == dlm->node_num) {
response = DLM_MASTER_RESP_YES;
/* this node will be the owner.
* go back and clean the mles on any
* other nodes */
dispatch_assert = 1;
} else
response = DLM_MASTER_RESP_NO;
} else {
// mlog(0, "this node is attempting to "
// "master lockres\n");
response = DLM_MASTER_RESP_MAYBE;
}
if (set_maybe)
set_bit(request->node_idx, tmpmle->maybe_map);
spin_unlock(&tmpmle->spinlock);
spin_unlock(&dlm->master_lock);
spin_unlock(&res->spinlock);
/* keep the mle attached to heartbeat events */
dlm_put_mle(tmpmle);
if (mle)
kmem_cache_free(dlm_mle_cache, mle);
goto send_response;
}
/*
* lockres doesn't exist on this node
* if there is an MLE_BLOCK, return NO
* if there is an MLE_MASTER, return MAYBE
* otherwise, add an MLE_BLOCK, return NO
*/
spin_lock(&dlm->master_lock);
found = dlm_find_mle(dlm, &tmpmle, name, namelen);
if (!found) {
/* this lockid has never been seen on this node yet */
// mlog(0, "no mle found\n");
if (!mle) {
spin_unlock(&dlm->master_lock);
spin_unlock(&dlm->spinlock);
mle = (struct dlm_master_list_entry *)
kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
if (!mle) {
response = DLM_MASTER_RESP_ERROR;
mlog_errno(-ENOMEM);
goto send_response;
}
spin_lock(&dlm->spinlock);
dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL,
name, namelen);
spin_unlock(&dlm->spinlock);
goto way_up_top;
}
// mlog(0, "this is second time thru, already allocated, "
// "add the block.\n");
set_bit(request->node_idx, mle->maybe_map);
list_add(&mle->list, &dlm->master_list);
response = DLM_MASTER_RESP_NO;
} else {
// mlog(0, "mle was found\n");
set_maybe = 1;
spin_lock(&tmpmle->spinlock);
if (tmpmle->master == dlm->node_num) {
mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
BUG();
}
if (tmpmle->type == DLM_MLE_BLOCK)
response = DLM_MASTER_RESP_NO;
else if (tmpmle->type == DLM_MLE_MIGRATION) {
mlog(0, "migration mle was found (%u->%u)\n",
tmpmle->master, tmpmle->new_master);
/* real master can respond on its own */
response = DLM_MASTER_RESP_NO;
} else
response = DLM_MASTER_RESP_MAYBE;
if (set_maybe)
set_bit(request->node_idx, tmpmle->maybe_map);
spin_unlock(&tmpmle->spinlock);
}
spin_unlock(&dlm->master_lock);
spin_unlock(&dlm->spinlock);
if (found) {
/* keep the mle attached to heartbeat events */
dlm_put_mle(tmpmle);
}
send_response:
if (dispatch_assert) {
if (response != DLM_MASTER_RESP_YES)
mlog(ML_ERROR, "invalid response %d\n", response);
if (!res) {
mlog(ML_ERROR, "bad lockres while trying to assert!\n");
BUG();
}
mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
dlm->node_num, res->lockname.len, res->lockname.name);
ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
DLM_ASSERT_MASTER_MLE_CLEANUP);
if (ret < 0) {
mlog(ML_ERROR, "failed to dispatch assert master work\n");
response = DLM_MASTER_RESP_ERROR;
}
}
dlm_put(dlm);
return response;
}
/*
* DLM_ASSERT_MASTER_MSG
*/
/*
* NOTE: this can be used for debugging
* can periodically run all locks owned by this node
* and re-assert across the cluster...
*/
static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
unsigned int namelen, void *nodemap,
u32 flags)
{
struct dlm_assert_master assert;
int to, tmpret;
struct dlm_node_iter iter;
int ret = 0;
int reassert;
BUG_ON(namelen > O2NM_MAX_NAME_LEN);
again:
reassert = 0;
/* note that if this nodemap is empty, it returns 0 */
dlm_node_iter_init(nodemap, &iter);
while ((to = dlm_node_iter_next(&iter)) >= 0) {
int r = 0;
mlog(0, "sending assert master to %d (%.*s)\n", to,
namelen, lockname);
memset(&assert, 0, sizeof(assert));
assert.node_idx = dlm->node_num;
assert.namelen = namelen;
memcpy(assert.name, lockname, namelen);
assert.flags = cpu_to_be32(flags);
tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
&assert, sizeof(assert), to, &r);
if (tmpret < 0) {
mlog(ML_ERROR, "assert_master returned %d!\n", tmpret);
if (!dlm_is_host_down(tmpret)) {
mlog(ML_ERROR, "unhandled error!\n");
BUG();
}
/* a node died. finish out the rest of the nodes. */
mlog(ML_ERROR, "link to %d went down!\n", to);
/* any nonzero status return will do */
ret = tmpret;
} else if (r < 0) {
/* ok, something horribly messed. kill thyself. */
mlog(ML_ERROR,"during assert master of %.*s to %u, "
"got %d.\n", namelen, lockname, to, r);
dlm_dump_lock_resources(dlm);
BUG();
} else if (r == EAGAIN) {
mlog(0, "%.*s: node %u create mles on other "
"nodes and requests a re-assert\n",
namelen, lockname, to);
reassert = 1;
}
}
if (reassert)
goto again;
return ret;
}
/*
* locks that can be taken here:
* dlm->spinlock
* res->spinlock
* mle->spinlock
* dlm->master_list
*
* if possible, TRIM THIS DOWN!!!
*/
int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data)
{
struct dlm_ctxt *dlm = data;
struct dlm_master_list_entry *mle = NULL;
struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
struct dlm_lock_resource *res = NULL;
char *name;
unsigned int namelen, hash;
u32 flags;
int master_request = 0;
int ret = 0;
if (!dlm_grab(dlm))
return 0;
name = assert->name;
namelen = assert->namelen;
hash = dlm_lockid_hash(name, namelen);
flags = be32_to_cpu(assert->flags);
if (namelen > DLM_LOCKID_NAME_MAX) {
mlog(ML_ERROR, "Invalid name length!");
goto done;
}
spin_lock(&dlm->spinlock);
if (flags)
mlog(0, "assert_master with flags: %u\n", flags);
/* find the MLE */
spin_lock(&dlm->master_lock);
if (!dlm_find_mle(dlm, &mle, name, namelen)) {
/* not an error, could be master just re-asserting */
mlog(0, "just got an assert_master from %u, but no "
"MLE for it! (%.*s)\n", assert->node_idx,
namelen, name);
} else {
int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
if (bit >= O2NM_MAX_NODES) {
/* not necessarily an error, though less likely.
* could be master just re-asserting. */
mlog(ML_ERROR, "no bits set in the maybe_map, but %u "
"is asserting! (%.*s)\n", assert->node_idx,
namelen, name);
} else if (bit != assert->node_idx) {
if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
mlog(0, "master %u was found, %u should "
"back off\n", assert->node_idx, bit);
} else {
/* with the fix for bug 569, a higher node
* number winning the mastery will respond
* YES to mastery requests, but this node
* had no way of knowing. let it pass. */
mlog(ML_ERROR, "%u is the lowest node, "
"%u is asserting. (%.*s) %u must "
"have begun after %u won.\n", bit,
assert->node_idx, namelen, name, bit,
assert->node_idx);
}
}
}
spin_unlock(&dlm->master_lock);
/* ok everything checks out with the MLE
* now check to see if there is a lockres */
res = __dlm_lookup_lockres(dlm, name, namelen, hash);
if (res) {
spin_lock(&res->spinlock);
if (res->state & DLM_LOCK_RES_RECOVERING) {
mlog(ML_ERROR, "%u asserting but %.*s is "
"RECOVERING!\n", assert->node_idx, namelen, name);
goto kill;
}
if (!mle) {
if (res->owner != assert->node_idx) {
mlog(ML_ERROR, "assert_master from "
"%u, but current owner is "
"%u! (%.*s)\n",
assert->node_idx, res->owner,
namelen, name);
goto kill;
}
} else if (mle->type != DLM_MLE_MIGRATION) {
if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
/* owner is just re-asserting */
if (res->owner == assert->node_idx) {
mlog(0, "owner %u re-asserting on "
"lock %.*s\n", assert->node_idx,
namelen, name);
goto ok;
}
mlog(ML_ERROR, "got assert_master from "
"node %u, but %u is the owner! "
"(%.*s)\n", assert->node_idx,
res->owner, namelen, name);
goto kill;
}
if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
mlog(ML_ERROR, "got assert from %u, but lock "
"with no owner should be "
"in-progress! (%.*s)\n",
assert->node_idx,
namelen, name);
goto kill;
}
} else /* mle->type == DLM_MLE_MIGRATION */ {
/* should only be getting an assert from new master */
if (assert->node_idx != mle->new_master) {
mlog(ML_ERROR, "got assert from %u, but "
"new master is %u, and old master "
"was %u (%.*s)\n",
assert->node_idx, mle->new_master,
mle->master, namelen, name);
goto kill;
}
}
ok:
spin_unlock(&res->spinlock);
}
spin_unlock(&dlm->spinlock);
// mlog(0, "woo! got an assert_master from node %u!\n",
// assert->node_idx);
if (mle) {
int extra_ref = 0;
int nn = -1;
spin_lock(&mle->spinlock);
if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
extra_ref = 1;
else {
/* MASTER mle: if any bits set in the response map
* then the calling node needs to re-assert to clear
* up nodes that this node contacted */
while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
nn+1)) < O2NM_MAX_NODES) {
if (nn != dlm->node_num && nn != assert->node_idx)
master_request = 1;
}
}
mle->master = assert->node_idx;
atomic_set(&mle->woken, 1);
wake_up(&mle->wq);
spin_unlock(&mle->spinlock);
if (mle->type == DLM_MLE_MIGRATION && res) {
mlog(0, "finishing off migration of lockres %.*s, "
"from %u to %u\n",
res->lockname.len, res->lockname.name,
dlm->node_num, mle->new_master);
spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_MIGRATING;
dlm_change_lockres_owner(dlm, res, mle->new_master);
BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
spin_unlock(&res->spinlock);
}
/* master is known, detach if not already detached */
dlm_mle_detach_hb_events(dlm, mle);
dlm_put_mle(mle);
if (extra_ref) {
/* the assert master message now balances the extra
* ref given by the master / migration request message.
* if this is the last put, it will be removed
* from the list. */
dlm_put_mle(mle);
}
}
done:
ret = 0;
if (res)
dlm_lockres_put(res);
dlm_put(dlm);
if (master_request) {
mlog(0, "need to tell master to reassert\n");
ret = EAGAIN; // positive. negative would shoot down the node.
}
return ret;
kill:
/* kill the caller! */
spin_unlock(&res->spinlock);
spin_unlock(&dlm->spinlock);
dlm_lockres_put(res);
mlog(ML_ERROR, "Bad message received from another node. Dumping state "
"and killing the other node now! This node is OK and can continue.\n");
dlm_dump_lock_resources(dlm);
dlm_put(dlm);
return -EINVAL;
}
int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
int ignore_higher, u8 request_from, u32 flags)
{
struct dlm_work_item *item;
item = kcalloc(1, sizeof(*item), GFP_KERNEL);
if (!item)
return -ENOMEM;
/* queue up work for dlm_assert_master_worker */
dlm_grab(dlm); /* get an extra ref for the work item */
dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
item->u.am.lockres = res; /* already have a ref */
/* can optionally ignore node numbers higher than this node */
item->u.am.ignore_higher = ignore_higher;
item->u.am.request_from = request_from;
item->u.am.flags = flags;
if (ignore_higher)
mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
res->lockname.name);
spin_lock(&dlm->work_lock);
list_add_tail(&item->list, &dlm->work_list);
spin_unlock(&dlm->work_lock);
schedule_work(&dlm->dispatched_work);
return 0;
}
static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
{
struct dlm_ctxt *dlm = data;
int ret = 0;
struct dlm_lock_resource *res;
unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
int ignore_higher;
int bit;
u8 request_from;
u32 flags;
dlm = item->dlm;
res = item->u.am.lockres;
ignore_higher = item->u.am.ignore_higher;
request_from = item->u.am.request_from;
flags = item->u.am.flags;
spin_lock(&dlm->spinlock);
memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
spin_unlock(&dlm->spinlock);
clear_bit(dlm->node_num, nodemap);
if (ignore_higher) {
/* if is this just to clear up mles for nodes below
* this node, do not send the message to the original
* caller or any node number higher than this */
clear_bit(request_from, nodemap);
bit = dlm->node_num;
while (1) {
bit = find_next_bit(nodemap, O2NM_MAX_NODES,
bit+1);
if (bit >= O2NM_MAX_NODES)
break;
clear_bit(bit, nodemap);
}
}
/* this call now finishes out the nodemap
* even if one or more nodes die */
mlog(0, "worker about to master %.*s here, this=%u\n",
res->lockname.len, res->lockname.name, dlm->node_num);
ret = dlm_do_assert_master(dlm, res->lockname.name,
res->lockname.len,
nodemap, flags);
if (ret < 0) {
/* no need to restart, we are done */
mlog_errno(ret);
}
dlm_lockres_put(res);
mlog(0, "finished with dlm_assert_master_worker\n");
}
/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
* We cannot wait for node recovery to complete to begin mastering this
* lockres because this lockres is used to kick off recovery! ;-)
* So, do a pre-check on all living nodes to see if any of those nodes
* think that $RECOVERY is currently mastered by a dead node. If so,
* we wait a short time to allow that node to get notified by its own
* heartbeat stack, then check again. All $RECOVERY lock resources
* mastered by dead nodes are purged when the hearbeat callback is
* fired, so we can know for sure that it is safe to continue once
* the node returns a live node or no node. */
static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
struct dlm_node_iter iter;
int nodenum;
int ret = 0;
u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
spin_lock(&dlm->spinlock);
dlm_node_iter_init(dlm->domain_map, &iter);
spin_unlock(&dlm->spinlock);
while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
/* do not send to self */
if (nodenum == dlm->node_num)
continue;
ret = dlm_do_master_requery(dlm, res, nodenum, &master);
if (ret < 0) {
mlog_errno(ret);
if (!dlm_is_host_down(ret))
BUG();
/* host is down, so answer for that node would be
* DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
}
if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
/* check to see if this master is in the recovery map */
spin_lock(&dlm->spinlock);
if (test_bit(master, dlm->recovery_map)) {
mlog(ML_NOTICE, "%s: node %u has not seen "
"node %u go down yet, and thinks the "
"dead node is mastering the recovery "
"lock. must wait.\n", dlm->name,
nodenum, master);
ret = -EAGAIN;
}
spin_unlock(&dlm->spinlock);
mlog(0, "%s: reco lock master is %u\n", dlm->name,
master);
break;
}
}
return ret;
}
/*
* DLM_MIGRATE_LOCKRES
*/
int dlm_migrate_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
u8 target)
{
struct dlm_master_list_entry *mle = NULL;
struct dlm_master_list_entry *oldmle = NULL;
struct dlm_migratable_lockres *mres = NULL;
int ret = -EINVAL;
const char *name;
unsigned int namelen;
int mle_added = 0;
struct list_head *queue, *iter;
int i;
struct dlm_lock *lock;
int empty = 1;
if (!dlm_grab(dlm))
return -EINVAL;
name = res->lockname.name;
namelen = res->lockname.len;
mlog(0, "migrating %.*s to %u\n", namelen, name, target);
/*
* ensure this lockres is a proper candidate for migration
*/
spin_lock(&res->spinlock);
if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
mlog(0, "cannot migrate lockres with unknown owner!\n");
spin_unlock(&res->spinlock);
goto leave;
}
if (res->owner != dlm->node_num) {
mlog(0, "cannot migrate lockres this node doesn't own!\n");
spin_unlock(&res->spinlock);
goto leave;
}
mlog(0, "checking queues...\n");
queue = &res->granted;
for (i=0; i<3; i++) {
list_for_each(iter, queue) {
lock = list_entry (iter, struct dlm_lock, list);
empty = 0;
if (lock->ml.node == dlm->node_num) {
mlog(0, "found a lock owned by this node "
"still on the %s queue! will not "
"migrate this lockres\n",
i==0 ? "granted" :
(i==1 ? "converting" : "blocked"));
spin_unlock(&res->spinlock);
ret = -ENOTEMPTY;
goto leave;
}
}
queue++;
}
mlog(0, "all locks on this lockres are nonlocal. continuing\n");
spin_unlock(&res->spinlock);
/* no work to do */
if (empty) {
mlog(0, "no locks were found on this lockres! done!\n");
ret = 0;
goto leave;
}
/*
* preallocate up front
* if this fails, abort
*/
ret = -ENOMEM;
mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_KERNEL);
if (!mres) {
mlog_errno(ret);
goto leave;
}
mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
GFP_KERNEL);
if (!mle) {
mlog_errno(ret);
goto leave;
}
ret = 0;
/*
* find a node to migrate the lockres to
*/
mlog(0, "picking a migration node\n");
spin_lock(&dlm->spinlock);
/* pick a new node */
if (!test_bit(target, dlm->domain_map) ||
target >= O2NM_MAX_NODES) {
target = dlm_pick_migration_target(dlm, res);
}
mlog(0, "node %u chosen for migration\n", target);
if (target >= O2NM_MAX_NODES ||
!test_bit(target, dlm->domain_map)) {
/* target chosen is not alive */
ret = -EINVAL;
}
if (ret) {
spin_unlock(&dlm->spinlock);
goto fail;
}
mlog(0, "continuing with target = %u\n", target);
/*
* clear any existing master requests and
* add the migration mle to the list
*/
spin_lock(&dlm->master_lock);
ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
namelen, target, dlm->node_num);
spin_unlock(&dlm->master_lock);
spin_unlock(&dlm->spinlock);
if (ret == -EEXIST) {
mlog(0, "another process is already migrating it\n");
goto fail;
}
mle_added = 1;
/*
* set the MIGRATING flag and flush asts
* if we fail after this we need to re-dirty the lockres
*/
if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
"the target went down.\n", res->lockname.len,
res->lockname.name, target);
spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_MIGRATING;
spin_unlock(&res->spinlock);
ret = -EINVAL;
}
fail:
if (oldmle) {
/* master is known, detach if not already detached */
dlm_mle_detach_hb_events(dlm, oldmle);
dlm_put_mle(oldmle);
}
if (ret < 0) {
if (mle_added) {
dlm_mle_detach_hb_events(dlm, mle);
dlm_put_mle(mle);
} else if (mle) {
kmem_cache_free(dlm_mle_cache, mle);
}
goto leave;
}
/*
* at this point, we have a migration target, an mle
* in the master list, and the MIGRATING flag set on
* the lockres
*/
/* get an extra reference on the mle.
* otherwise the assert_master from the new
* master will destroy this.
* also, make sure that all callers of dlm_get_mle
* take both dlm->spinlock and dlm->master_lock */
spin_lock(&dlm->spinlock);
spin_lock(&dlm->master_lock);
dlm_get_mle(mle);
spin_unlock(&dlm->master_lock);
spin_unlock(&dlm->spinlock);
/* notify new node and send all lock state */
/* call send_one_lockres with migration flag.
* this serves as notice to the target node that a
* migration is starting. */
ret = dlm_send_one_lockres(dlm, res, mres, target,
DLM_MRES_MIGRATION);
if (ret < 0) {
mlog(0, "migration to node %u failed with %d\n",
target, ret);
/* migration failed, detach and clean up mle */
dlm_mle_detach_hb_events(dlm, mle);
dlm_put_mle(mle);
dlm_put_mle(mle);
goto leave;
}
/* at this point, the target sends a message to all nodes,
* (using dlm_do_migrate_request). this node is skipped since
* we had to put an mle in the list to begin the process. this
* node now waits for target to do an assert master. this node
* will be the last one notified, ensuring that the migration
* is complete everywhere. if the target dies while this is
* going on, some nodes could potentially see the target as the
* master, so it is important that my recovery finds the migration
* mle and sets the master to UNKNONWN. */
/* wait for new node to assert master */
while (1) {
ret = wait_event_interruptible_timeout(mle->wq,
(atomic_read(&mle->woken) == 1),
msecs_to_jiffies(5000));
if (ret >= 0) {
if (atomic_read(&mle->woken) == 1 ||
res->owner == target)
break;
mlog(0, "timed out during migration\n");
/* avoid hang during shutdown when migrating lockres
* to a node which also goes down */
if (dlm_is_node_dead(dlm, target)) {
mlog(0, "%s:%.*s: expected migration target %u "
"is no longer up. restarting.\n",
dlm->name, res->lockname.len,
res->lockname.name, target);
ret = -ERESTARTSYS;
}
}
if (ret == -ERESTARTSYS) {
/* migration failed, detach and clean up mle */
dlm_mle_detach_hb_events(dlm, mle);
dlm_put_mle(mle);
dlm_put_mle(mle);
goto leave;
}
/* TODO: if node died: stop, clean up, return error */
}
/* all done, set the owner, clear the flag */
spin_lock(&res->spinlock);
dlm_set_lockres_owner(dlm, res, target);
res->state &= ~DLM_LOCK_RES_MIGRATING;
dlm_remove_nonlocal_locks(dlm, res);
spin_unlock(&res->spinlock);
wake_up(&res->wq);
/* master is known, detach if not already detached */
dlm_mle_detach_hb_events(dlm, mle);
dlm_put_mle(mle);
ret = 0;
dlm_lockres_calc_usage(dlm, res);
leave:
/* re-dirty the lockres if we failed */
if (ret < 0)
dlm_kick_thread(dlm, res);
/* TODO: cleanup */
if (mres)
free_page((unsigned long)mres);
dlm_put(dlm);
mlog(0, "returning %d\n", ret);
return ret;
}
EXPORT_SYMBOL_GPL(dlm_migrate_lockres);
int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
int ret;
spin_lock(&dlm->ast_lock);
spin_lock(&lock->spinlock);
ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
spin_unlock(&lock->spinlock);
spin_unlock(&dlm->ast_lock);
return ret;
}
static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
u8 mig_target)
{
int can_proceed;
spin_lock(&res->spinlock);
can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
spin_unlock(&res->spinlock);
/* target has died, so make the caller break out of the
* wait_event, but caller must recheck the domain_map */
spin_lock(&dlm->spinlock);
if (!test_bit(mig_target, dlm->domain_map))
can_proceed = 1;
spin_unlock(&dlm->spinlock);
return can_proceed;
}
int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
{
int ret;
spin_lock(&res->spinlock);
ret = !!(res->state & DLM_LOCK_RES_DIRTY);
spin_unlock(&res->spinlock);
return ret;
}
static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
u8 target)
{
int ret = 0;
mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
res->lockname.len, res->lockname.name, dlm->node_num,
target);
/* need to set MIGRATING flag on lockres. this is done by
* ensuring that all asts have been flushed for this lockres. */
spin_lock(&res->spinlock);
BUG_ON(res->migration_pending);
res->migration_pending = 1;
/* strategy is to reserve an extra ast then release
* it below, letting the release do all of the work */
__dlm_lockres_reserve_ast(res);
spin_unlock(&res->spinlock);
/* now flush all the pending asts.. hang out for a bit */
dlm_kick_thread(dlm, res);
wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
dlm_lockres_release_ast(dlm, res);
mlog(0, "about to wait on migration_wq, dirty=%s\n",
res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
/* if the extra ref we just put was the final one, this
* will pass thru immediately. otherwise, we need to wait
* for the last ast to finish. */
again:
ret = wait_event_interruptible_timeout(dlm->migration_wq,
dlm_migration_can_proceed(dlm, res, target),
msecs_to_jiffies(1000));
if (ret < 0) {
mlog(0, "woken again: migrating? %s, dead? %s\n",
res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
test_bit(target, dlm->domain_map) ? "no":"yes");
} else {
mlog(0, "all is well: migrating? %s, dead? %s\n",
res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
test_bit(target, dlm->domain_map) ? "no":"yes");
}
if (!dlm_migration_can_proceed(dlm, res, target)) {
mlog(0, "trying again...\n");
goto again;
}
/* did the target go down or die? */
spin_lock(&dlm->spinlock);
if (!test_bit(target, dlm->domain_map)) {
mlog(ML_ERROR, "aha. migration target %u just went down\n",
target);
ret = -EHOSTDOWN;
}
spin_unlock(&dlm->spinlock);
/*
* at this point:
*
* o the DLM_LOCK_RES_MIGRATING flag is set
* o there are no pending asts on this lockres
* o all processes trying to reserve an ast on this
* lockres must wait for the MIGRATING flag to clear
*/
return ret;
}
/* last step in the migration process.
* original master calls this to free all of the dlm_lock
* structures that used to be for other nodes. */
static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
struct list_head *iter, *iter2;
struct list_head *queue = &res->granted;
int i;
struct dlm_lock *lock;
assert_spin_locked(&res->spinlock);
BUG_ON(res->owner == dlm->node_num);
for (i=0; i<3; i++) {
list_for_each_safe(iter, iter2, queue) {
lock = list_entry (iter, struct dlm_lock, list);
if (lock->ml.node != dlm->node_num) {
mlog(0, "putting lock for node %u\n",
lock->ml.node);
/* be extra careful */
BUG_ON(!list_empty(&lock->ast_list));
BUG_ON(!list_empty(&lock->bast_list));
BUG_ON(lock->ast_pending);
BUG_ON(lock->bast_pending);
list_del_init(&lock->list);
dlm_lock_put(lock);
}
}
queue++;
}
}
/* for now this is not too intelligent. we will
* need stats to make this do the right thing.
* this just finds the first lock on one of the
* queues and uses that node as the target. */
static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
int i;
struct list_head *queue = &res->granted;
struct list_head *iter;
struct dlm_lock *lock;
int nodenum;
assert_spin_locked(&dlm->spinlock);
spin_lock(&res->spinlock);
for (i=0; i<3; i++) {
list_for_each(iter, queue) {
/* up to the caller to make sure this node
* is alive */
lock = list_entry (iter, struct dlm_lock, list);
if (lock->ml.node != dlm->node_num) {
spin_unlock(&res->spinlock);
return lock->ml.node;
}
}
queue++;
}
spin_unlock(&res->spinlock);
mlog(0, "have not found a suitable target yet! checking domain map\n");
/* ok now we're getting desperate. pick anyone alive. */
nodenum = -1;
while (1) {
nodenum = find_next_bit(dlm->domain_map,
O2NM_MAX_NODES, nodenum+1);
mlog(0, "found %d in domain map\n", nodenum);
if (nodenum >= O2NM_MAX_NODES)
break;
if (nodenum != dlm->node_num) {
mlog(0, "picking %d\n", nodenum);
return nodenum;
}
}
mlog(0, "giving up. no master to migrate to\n");
return DLM_LOCK_RES_OWNER_UNKNOWN;
}
/* this is called by the new master once all lockres
* data has been received */
static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
u8 master, u8 new_master,
struct dlm_node_iter *iter)
{
struct dlm_migrate_request migrate;
int ret, status = 0;
int nodenum;
memset(&migrate, 0, sizeof(migrate));
migrate.namelen = res->lockname.len;
memcpy(migrate.name, res->lockname.name, migrate.namelen);
migrate.new_master = new_master;
migrate.master = master;
ret = 0;
/* send message to all nodes, except the master and myself */
while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
if (nodenum == master ||
nodenum == new_master)
continue;
ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
&migrate, sizeof(migrate), nodenum,
&status);
if (ret < 0)
mlog_errno(ret);
else if (status < 0) {
mlog(0, "migrate request (node %u) returned %d!\n",
nodenum, status);
ret = status;
}
}
if (ret < 0)
mlog_errno(ret);
mlog(0, "returning ret=%d\n", ret);
return ret;
}
/* if there is an existing mle for this lockres, we now know who the master is.
* (the one who sent us *this* message) we can clear it up right away.
* since the process that put the mle on the list still has a reference to it,
* we can unhash it now, set the master and wake the process. as a result,
* we will have no mle in the list to start with. now we can add an mle for
* the migration and this should be the only one found for those scanning the
* list. */
int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data)
{
struct dlm_ctxt *dlm = data;
struct dlm_lock_resource *res = NULL;
struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
const char *name;
unsigned int namelen, hash;
int ret = 0;
if (!dlm_grab(dlm))
return -EINVAL;
name = migrate->name;
namelen = migrate->namelen;
hash = dlm_lockid_hash(name, namelen);
/* preallocate.. if this fails, abort */
mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
GFP_KERNEL);
if (!mle) {
ret = -ENOMEM;
goto leave;
}
/* check for pre-existing lock */
spin_lock(&dlm->spinlock);
res = __dlm_lookup_lockres(dlm, name, namelen, hash);
spin_lock(&dlm->master_lock);
if (res) {
spin_lock(&res->spinlock);
if (res->state & DLM_LOCK_RES_RECOVERING) {
/* if all is working ok, this can only mean that we got
* a migrate request from a node that we now see as
* dead. what can we do here? drop it to the floor? */
spin_unlock(&res->spinlock);
mlog(ML_ERROR, "Got a migrate request, but the "
"lockres is marked as recovering!");
kmem_cache_free(dlm_mle_cache, mle);
ret = -EINVAL; /* need a better solution */
goto unlock;
}
res->state |= DLM_LOCK_RES_MIGRATING;
spin_unlock(&res->spinlock);
}
/* ignore status. only nonzero status would BUG. */
ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
name, namelen,
migrate->new_master,
migrate->master);
unlock:
spin_unlock(&dlm->master_lock);
spin_unlock(&dlm->spinlock);
if (oldmle) {
/* master is known, detach if not already detached */
dlm_mle_detach_hb_events(dlm, oldmle);
dlm_put_mle(oldmle);
}
if (res)
dlm_lockres_put(res);
leave:
dlm_put(dlm);
return ret;
}
/* must be holding dlm->spinlock and dlm->master_lock
* when adding a migration mle, we can clear any other mles
* in the master list because we know with certainty that
* the master is "master". so we remove any old mle from
* the list after setting it's master field, and then add
* the new migration mle. this way we can hold with the rule
* of having only one mle for a given lock name at all times. */
static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_master_list_entry *mle,
struct dlm_master_list_entry **oldmle,
const char *name, unsigned int namelen,
u8 new_master, u8 master)
{
int found;
int ret = 0;
*oldmle = NULL;
mlog_entry_void();
assert_spin_locked(&dlm->spinlock);
assert_spin_locked(&dlm->master_lock);
/* caller is responsible for any ref taken here on oldmle */
found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
if (found) {
struct dlm_master_list_entry *tmp = *oldmle;
spin_lock(&tmp->spinlock);
if (tmp->type == DLM_MLE_MIGRATION) {
if (master == dlm->node_num) {
/* ah another process raced me to it */
mlog(0, "tried to migrate %.*s, but some "
"process beat me to it\n",
namelen, name);
ret = -EEXIST;
} else {
/* bad. 2 NODES are trying to migrate! */
mlog(ML_ERROR, "migration error mle: "
"master=%u new_master=%u // request: "
"master=%u new_master=%u // "
"lockres=%.*s\n",
tmp->master, tmp->new_master,
master, new_master,
namelen, name);
BUG();
}
} else {
/* this is essentially what assert_master does */
tmp->master = master;
atomic_set(&tmp->woken, 1);
wake_up(&tmp->wq);
/* remove it from the list so that only one
* mle will be found */
list_del_init(&tmp->list);
}
spin_unlock(&tmp->spinlock);
}
/* now add a migration mle to the tail of the list */
dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
mle->new_master = new_master;
mle->master = master;
/* do this for consistency with other mle types */
set_bit(new_master, mle->maybe_map);
list_add(&mle->list, &dlm->master_list);
return ret;
}
void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
{
struct list_head *iter, *iter2;
struct dlm_master_list_entry *mle;
struct dlm_lock_resource *res;
unsigned int hash;
mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
top:
assert_spin_locked(&dlm->spinlock);
/* clean the master list */
spin_lock(&dlm->master_lock);
list_for_each_safe(iter, iter2, &dlm->master_list) {
mle = list_entry(iter, struct dlm_master_list_entry, list);
BUG_ON(mle->type != DLM_MLE_BLOCK &&
mle->type != DLM_MLE_MASTER &&
mle->type != DLM_MLE_MIGRATION);
/* MASTER mles are initiated locally. the waiting
* process will notice the node map change
* shortly. let that happen as normal. */
if (mle->type == DLM_MLE_MASTER)
continue;
/* BLOCK mles are initiated by other nodes.
* need to clean up if the dead node would have
* been the master. */
if (mle->type == DLM_MLE_BLOCK) {
int bit;
spin_lock(&mle->spinlock);
bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
if (bit != dead_node) {
mlog(0, "mle found, but dead node %u would "
"not have been master\n", dead_node);
spin_unlock(&mle->spinlock);
} else {
/* must drop the refcount by one since the
* assert_master will never arrive. this
* may result in the mle being unlinked and
* freed, but there may still be a process
* waiting in the dlmlock path which is fine. */
mlog(ML_ERROR, "node %u was expected master\n",
dead_node);
atomic_set(&mle->woken, 1);
spin_unlock(&mle->spinlock);
wake_up(&mle->wq);
/* do not need events any longer, so detach
* from heartbeat */
__dlm_mle_detach_hb_events(dlm, mle);
__dlm_put_mle(mle);
}
continue;
}
/* everything else is a MIGRATION mle */
/* the rule for MIGRATION mles is that the master
* becomes UNKNOWN if *either* the original or
* the new master dies. all UNKNOWN lockreses
* are sent to whichever node becomes the recovery
* master. the new master is responsible for
* determining if there is still a master for
* this lockres, or if he needs to take over
* mastery. either way, this node should expect
* another message to resolve this. */
if (mle->master != dead_node &&
mle->new_master != dead_node)
continue;
/* if we have reached this point, this mle needs to
* be removed from the list and freed. */
/* remove from the list early. NOTE: unlinking
* list_head while in list_for_each_safe */
spin_lock(&mle->spinlock);
list_del_init(&mle->list);
atomic_set(&mle->woken, 1);
spin_unlock(&mle->spinlock);
wake_up(&mle->wq);
mlog(0, "node %u died during migration from "
"%u to %u!\n", dead_node,
mle->master, mle->new_master);
/* if there is a lockres associated with this
* mle, find it and set its owner to UNKNOWN */
hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
res = __dlm_lookup_lockres(dlm, mle->u.name.name,
mle->u.name.len, hash);
if (res) {
/* unfortunately if we hit this rare case, our
* lock ordering is messed. we need to drop
* the master lock so that we can take the
* lockres lock, meaning that we will have to
* restart from the head of list. */
spin_unlock(&dlm->master_lock);
/* move lockres onto recovery list */
spin_lock(&res->spinlock);
dlm_set_lockres_owner(dlm, res,
DLM_LOCK_RES_OWNER_UNKNOWN);
dlm_move_lockres_to_recovery_list(dlm, res);
spin_unlock(&res->spinlock);
dlm_lockres_put(res);
/* about to get rid of mle, detach from heartbeat */
__dlm_mle_detach_hb_events(dlm, mle);
/* dump the mle */
spin_lock(&dlm->master_lock);
__dlm_put_mle(mle);
spin_unlock(&dlm->master_lock);
/* restart */
goto top;
}
/* this may be the last reference */
__dlm_put_mle(mle);
}
spin_unlock(&dlm->master_lock);
}
int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
u8 old_master)
{
struct dlm_node_iter iter;
int ret = 0;
spin_lock(&dlm->spinlock);
dlm_node_iter_init(dlm->domain_map, &iter);
clear_bit(old_master, iter.node_map);
clear_bit(dlm->node_num, iter.node_map);
spin_unlock(&dlm->spinlock);
mlog(0, "now time to do a migrate request to other nodes\n");
ret = dlm_do_migrate_request(dlm, res, old_master,
dlm->node_num, &iter);
if (ret < 0) {
mlog_errno(ret);
goto leave;
}
mlog(0, "doing assert master of %.*s to all except the original node\n",
res->lockname.len, res->lockname.name);
/* this call now finishes out the nodemap
* even if one or more nodes die */
ret = dlm_do_assert_master(dlm, res->lockname.name,
res->lockname.len, iter.node_map,
DLM_ASSERT_MASTER_FINISH_MIGRATION);
if (ret < 0) {
/* no longer need to retry. all living nodes contacted. */
mlog_errno(ret);
ret = 0;
}
memset(iter.node_map, 0, sizeof(iter.node_map));
set_bit(old_master, iter.node_map);
mlog(0, "doing assert master of %.*s back to %u\n",
res->lockname.len, res->lockname.name, old_master);
ret = dlm_do_assert_master(dlm, res->lockname.name,
res->lockname.len, iter.node_map,
DLM_ASSERT_MASTER_FINISH_MIGRATION);
if (ret < 0) {
mlog(0, "assert master to original master failed "
"with %d.\n", ret);
/* the only nonzero status here would be because of
* a dead original node. we're done. */
ret = 0;
}
/* all done, set the owner, clear the flag */
spin_lock(&res->spinlock);
dlm_set_lockres_owner(dlm, res, dlm->node_num);
res->state &= ~DLM_LOCK_RES_MIGRATING;
spin_unlock(&res->spinlock);
/* re-dirty it on the new master */
dlm_kick_thread(dlm, res);
wake_up(&res->wq);
leave:
return ret;
}
/*
* LOCKRES AST REFCOUNT
* this is integral to migration
*/
/* for future intent to call an ast, reserve one ahead of time.
* this should be called only after waiting on the lockres
* with dlm_wait_on_lockres, and while still holding the
* spinlock after the call. */
void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
{
assert_spin_locked(&res->spinlock);
if (res->state & DLM_LOCK_RES_MIGRATING) {
__dlm_print_one_lock_resource(res);
}
BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
atomic_inc(&res->asts_reserved);
}
/*
* used to drop the reserved ast, either because it went unused,
* or because the ast/bast was actually called.
*
* also, if there is a pending migration on this lockres,
* and this was the last pending ast on the lockres,
* atomically set the MIGRATING flag before we drop the lock.
* this is how we ensure that migration can proceed with no
* asts in progress. note that it is ok if the state of the
* queues is such that a lock should be granted in the future
* or that a bast should be fired, because the new master will
* shuffle the lists on this lockres as soon as it is migrated.
*/
void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
return;
if (!res->migration_pending) {
spin_unlock(&res->spinlock);
return;
}
BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
res->migration_pending = 0;
res->state |= DLM_LOCK_RES_MIGRATING;
spin_unlock(&res->spinlock);
wake_up(&res->wq);
wake_up(&dlm->migration_wq);
}
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