dlm: use rwlock for rsb hash table

The conversion to rhashtable introduced a hash table lock per lockspace,
in place of per bucket locks.  To make this more scalable, switch to
using a rwlock for hash table access.  The common case fast path uses
it as a read lock.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This commit is contained in:
Alexander Aring 2024-04-15 14:39:42 -04:00 committed by David Teigland
parent b1f2381c1a
commit e91313591b
7 changed files with 206 additions and 87 deletions

View file

@ -413,7 +413,7 @@ static void *table_seq_start(struct seq_file *seq, loff_t *pos)
else
list = &ls->ls_keep;
spin_lock_bh(&ls->ls_rsbtbl_lock);
read_lock_bh(&ls->ls_rsbtbl_lock);
return seq_list_start(list, *pos);
}
@ -434,7 +434,7 @@ static void table_seq_stop(struct seq_file *seq, void *iter_ptr)
{
struct dlm_ls *ls = seq->private;
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
}
static const struct seq_operations format1_seq_ops = {

View file

@ -200,9 +200,9 @@ static struct dlm_rsb *find_rsb_root(struct dlm_ls *ls, const char *name,
struct dlm_rsb *r;
int rv;
spin_lock_bh(&ls->ls_rsbtbl_lock);
read_lock_bh(&ls->ls_rsbtbl_lock);
rv = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
if (!rv)
return r;

View file

@ -585,7 +585,7 @@ struct dlm_ls {
spinlock_t ls_lkbidr_spin;
struct rhashtable ls_rsbtbl;
spinlock_t ls_rsbtbl_lock;
rwlock_t ls_rsbtbl_lock;
struct list_head ls_toss;
struct list_head ls_keep;

View file

@ -342,15 +342,15 @@ void dlm_hold_rsb(struct dlm_rsb *r)
/* TODO move this to lib/refcount.c */
static __must_check bool
dlm_refcount_dec_and_lock_bh(refcount_t *r, spinlock_t *lock)
dlm_refcount_dec_and_write_lock_bh(refcount_t *r, rwlock_t *lock)
__cond_acquires(lock)
{
if (refcount_dec_not_one(r))
return false;
spin_lock_bh(lock);
write_lock_bh(lock);
if (!refcount_dec_and_test(r)) {
spin_unlock_bh(lock);
write_unlock_bh(lock);
return false;
}
@ -358,11 +358,11 @@ __cond_acquires(lock)
}
/* TODO move this to include/linux/kref.h */
static inline int dlm_kref_put_lock_bh(struct kref *kref,
void (*release)(struct kref *kref),
spinlock_t *lock)
static inline int dlm_kref_put_write_lock_bh(struct kref *kref,
void (*release)(struct kref *kref),
rwlock_t *lock)
{
if (dlm_refcount_dec_and_lock_bh(&kref->refcount, lock)) {
if (dlm_refcount_dec_and_write_lock_bh(&kref->refcount, lock)) {
release(kref);
return 1;
}
@ -378,10 +378,10 @@ static void put_rsb(struct dlm_rsb *r)
struct dlm_ls *ls = r->res_ls;
int rv;
rv = dlm_kref_put_lock_bh(&r->res_ref, toss_rsb,
&ls->ls_rsbtbl_lock);
rv = dlm_kref_put_write_lock_bh(&r->res_ref, toss_rsb,
&ls->ls_rsbtbl_lock);
if (rv)
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
}
void dlm_put_rsb(struct dlm_rsb *r)
@ -603,7 +603,7 @@ void dlm_rsb_toss_timer(struct timer_list *timer)
* a caching handling and the other holders might to put
* this rsb out of the toss state.
*/
rv = spin_trylock(&ls->ls_rsbtbl_lock);
rv = write_trylock(&ls->ls_rsbtbl_lock);
if (!rv) {
spin_unlock(&ls->ls_toss_q_lock);
/* rearm again try timer */
@ -618,7 +618,7 @@ void dlm_rsb_toss_timer(struct timer_list *timer)
/* not necessary to held the ls_rsbtbl_lock when
* calling send_remove()
*/
spin_unlock(&ls->ls_rsbtbl_lock);
write_unlock(&ls->ls_rsbtbl_lock);
/* remove the rsb out of the toss queue its gone
* drom DLM now
@ -702,16 +702,8 @@ int dlm_search_rsb_tree(struct rhashtable *rhash, const void *name, int len,
static int rsb_insert(struct dlm_rsb *rsb, struct rhashtable *rhash)
{
int rv;
rv = rhashtable_insert_fast(rhash, &rsb->res_node,
dlm_rhash_rsb_params);
if (rv == -EEXIST) {
log_print("%s match", __func__);
dlm_dump_rsb(rsb);
}
return rv;
return rhashtable_insert_fast(rhash, &rsb->res_node,
dlm_rhash_rsb_params);
}
/*
@ -806,24 +798,47 @@ static int find_rsb_dir(struct dlm_ls *ls, const void *name, int len,
goto out;
}
spin_lock_bh(&ls->ls_rsbtbl_lock);
retry_lookup:
/* check if the rsb is in keep state under read lock - likely path */
read_lock_bh(&ls->ls_rsbtbl_lock);
error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
if (error)
if (error) {
read_unlock_bh(&ls->ls_rsbtbl_lock);
goto do_new;
}
/*
* rsb is active, so we can't check master_nodeid without lock_rsb.
*/
if (rsb_flag(r, RSB_TOSS))
if (rsb_flag(r, RSB_TOSS)) {
read_unlock_bh(&ls->ls_rsbtbl_lock);
goto do_toss;
}
kref_get(&r->res_ref);
goto out_unlock;
read_unlock_bh(&ls->ls_rsbtbl_lock);
goto out;
do_toss:
write_lock_bh(&ls->ls_rsbtbl_lock);
/* retry lookup under write lock to see if its still in toss state
* if not it's in keep state and we relookup - unlikely path.
*/
error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
if (!error) {
if (!rsb_flag(r, RSB_TOSS)) {
write_unlock_bh(&ls->ls_rsbtbl_lock);
goto retry_lookup;
}
} else {
write_unlock_bh(&ls->ls_rsbtbl_lock);
goto do_new;
}
/*
* rsb found inactive (master_nodeid may be out of date unless
* we are the dir_nodeid or were the master) No other thread
@ -837,8 +852,9 @@ static int find_rsb_dir(struct dlm_ls *ls, const void *name, int len,
log_debug(ls, "find_rsb toss from_other %d master %d dir %d %s",
from_nodeid, r->res_master_nodeid, dir_nodeid,
r->res_name);
write_unlock_bh(&ls->ls_rsbtbl_lock);
error = -ENOTBLK;
goto out_unlock;
goto out;
}
if ((r->res_master_nodeid != our_nodeid) && from_dir) {
@ -868,9 +884,9 @@ static int find_rsb_dir(struct dlm_ls *ls, const void *name, int len,
*/
kref_init(&r->res_ref);
rsb_delete_toss_timer(ls, r);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
goto out_unlock;
goto out;
do_new:
@ -879,15 +895,13 @@ static int find_rsb_dir(struct dlm_ls *ls, const void *name, int len,
*/
if (error == -EBADR && !create)
goto out_unlock;
goto out;
error = get_rsb_struct(ls, name, len, &r);
if (error == -EAGAIN) {
spin_unlock_bh(&ls->ls_rsbtbl_lock);
if (error == -EAGAIN)
goto retry;
}
if (error)
goto out_unlock;
goto out;
r->res_hash = hash;
r->res_dir_nodeid = dir_nodeid;
@ -909,7 +923,7 @@ static int find_rsb_dir(struct dlm_ls *ls, const void *name, int len,
dlm_free_rsb(r);
r = NULL;
error = -ENOTBLK;
goto out_unlock;
goto out;
}
if (from_other) {
@ -929,11 +943,20 @@ static int find_rsb_dir(struct dlm_ls *ls, const void *name, int len,
}
out_add:
write_lock_bh(&ls->ls_rsbtbl_lock);
error = rsb_insert(r, &ls->ls_rsbtbl);
if (!error)
if (error == -EEXIST) {
/* somebody else was faster and it seems the
* rsb exists now, we do a whole relookup
*/
write_unlock_bh(&ls->ls_rsbtbl_lock);
dlm_free_rsb(r);
goto retry_lookup;
} else if (!error) {
list_add(&r->res_rsbs_list, &ls->ls_keep);
out_unlock:
spin_unlock_bh(&ls->ls_rsbtbl_lock);
}
write_unlock_bh(&ls->ls_rsbtbl_lock);
out:
*r_ret = r;
return error;
@ -957,24 +980,49 @@ static int find_rsb_nodir(struct dlm_ls *ls, const void *name, int len,
if (error < 0)
goto out;
spin_lock_bh(&ls->ls_rsbtbl_lock);
retry_lookup:
/* check if the rsb is in keep state under read lock - likely path */
read_lock_bh(&ls->ls_rsbtbl_lock);
error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
if (error)
if (error) {
read_unlock_bh(&ls->ls_rsbtbl_lock);
goto do_new;
}
if (rsb_flag(r, RSB_TOSS))
if (rsb_flag(r, RSB_TOSS)) {
read_unlock_bh(&ls->ls_rsbtbl_lock);
goto do_toss;
}
/*
* rsb is active, so we can't check master_nodeid without lock_rsb.
*/
kref_get(&r->res_ref);
goto out_unlock;
read_unlock_bh(&ls->ls_rsbtbl_lock);
goto out;
do_toss:
write_lock_bh(&ls->ls_rsbtbl_lock);
/* retry lookup under write lock to see if its still in toss state
* if not it's in keep state and we relookup - unlikely path.
*/
error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
if (!error) {
if (!rsb_flag(r, RSB_TOSS)) {
write_unlock_bh(&ls->ls_rsbtbl_lock);
goto retry_lookup;
}
} else {
write_unlock_bh(&ls->ls_rsbtbl_lock);
goto do_new;
}
/*
* rsb found inactive. No other thread is using this rsb because
* it's on the toss list, so we can look at or update
@ -987,8 +1035,9 @@ static int find_rsb_nodir(struct dlm_ls *ls, const void *name, int len,
log_error(ls, "find_rsb toss from_nodeid %d master %d dir %d",
from_nodeid, r->res_master_nodeid, dir_nodeid);
dlm_print_rsb(r);
write_unlock_bh(&ls->ls_rsbtbl_lock);
error = -ENOTBLK;
goto out_unlock;
goto out;
}
if (!recover && (r->res_master_nodeid != our_nodeid) &&
@ -1010,9 +1059,9 @@ static int find_rsb_nodir(struct dlm_ls *ls, const void *name, int len,
*/
kref_init(&r->res_ref);
rsb_delete_toss_timer(ls, r);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
goto out_unlock;
goto out;
do_new:
@ -1022,11 +1071,10 @@ static int find_rsb_nodir(struct dlm_ls *ls, const void *name, int len,
error = get_rsb_struct(ls, name, len, &r);
if (error == -EAGAIN) {
spin_unlock_bh(&ls->ls_rsbtbl_lock);
goto retry;
}
if (error)
goto out_unlock;
goto out;
r->res_hash = hash;
r->res_dir_nodeid = dir_nodeid;
@ -1034,11 +1082,20 @@ static int find_rsb_nodir(struct dlm_ls *ls, const void *name, int len,
r->res_nodeid = (dir_nodeid == our_nodeid) ? 0 : dir_nodeid;
kref_init(&r->res_ref);
write_lock_bh(&ls->ls_rsbtbl_lock);
error = rsb_insert(r, &ls->ls_rsbtbl);
if (!error)
if (error == -EEXIST) {
/* somebody else was faster and it seems the
* rsb exists now, we do a whole relookup
*/
write_unlock_bh(&ls->ls_rsbtbl_lock);
dlm_free_rsb(r);
goto retry_lookup;
} else if (!error) {
list_add(&r->res_rsbs_list, &ls->ls_keep);
out_unlock:
spin_unlock_bh(&ls->ls_rsbtbl_lock);
}
write_unlock_bh(&ls->ls_rsbtbl_lock);
out:
*r_ret = r;
return error;
@ -1251,18 +1308,23 @@ int dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, const char *name,
if (error < 0)
return error;
spin_lock_bh(&ls->ls_rsbtbl_lock);
retry_lookup:
/* check if the rsb is in keep state under read lock - likely path */
read_lock_bh(&ls->ls_rsbtbl_lock);
error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
if (!error) {
if (rsb_flag(r, RSB_TOSS))
if (rsb_flag(r, RSB_TOSS)) {
read_unlock_bh(&ls->ls_rsbtbl_lock);
goto do_toss;
}
/* because the rsb is active, we need to lock_rsb before
* checking/changing re_master_nodeid
*/
hold_rsb(r);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
lock_rsb(r);
__dlm_master_lookup(ls, r, our_nodeid, from_nodeid, false,
@ -1274,10 +1336,31 @@ int dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, const char *name,
return 0;
} else {
read_unlock_bh(&ls->ls_rsbtbl_lock);
goto not_found;
}
do_toss:
/* unlikely path - relookup under write */
write_lock_bh(&ls->ls_rsbtbl_lock);
/* rsb_mod_timer() requires to held ls_rsbtbl_lock in write lock
* check if the rsb is still in toss state, if not relookup
*/
error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
if (!error) {
if (!rsb_flag(r, RSB_TOSS)) {
write_unlock_bh(&ls->ls_rsbtbl_lock);
/* something as changed, very unlikely but
* try again
*/
goto retry_lookup;
}
} else {
write_unlock_bh(&ls->ls_rsbtbl_lock);
goto not_found;
}
/* because the rsb is inactive (on toss list), it's not refcounted
* and lock_rsb is not used, but is protected by the rsbtbl lock
*/
@ -1287,18 +1370,16 @@ int dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, const char *name,
rsb_mod_timer(ls, r);
/* the rsb was inactive (on toss list) */
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
return 0;
not_found:
error = get_rsb_struct(ls, name, len, &r);
if (error == -EAGAIN) {
spin_unlock_bh(&ls->ls_rsbtbl_lock);
if (error == -EAGAIN)
goto retry;
}
if (error)
goto out_unlock;
goto out;
r->res_hash = hash;
r->res_dir_nodeid = our_nodeid;
@ -1307,22 +1388,30 @@ int dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, const char *name,
kref_init(&r->res_ref);
rsb_set_flag(r, RSB_TOSS);
write_lock_bh(&ls->ls_rsbtbl_lock);
error = rsb_insert(r, &ls->ls_rsbtbl);
if (error) {
if (error == -EEXIST) {
/* somebody else was faster and it seems the
* rsb exists now, we do a whole relookup
*/
write_unlock_bh(&ls->ls_rsbtbl_lock);
dlm_free_rsb(r);
goto retry_lookup;
} else if (error) {
write_unlock_bh(&ls->ls_rsbtbl_lock);
/* should never happen */
dlm_free_rsb(r);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
goto retry;
}
list_add(&r->res_rsbs_list, &ls->ls_toss);
rsb_mod_timer(ls, r);
write_unlock_bh(&ls->ls_rsbtbl_lock);
if (result)
*result = DLM_LU_ADD;
*r_nodeid = from_nodeid;
out_unlock:
spin_unlock_bh(&ls->ls_rsbtbl_lock);
out:
return error;
}
@ -1330,12 +1419,12 @@ static void dlm_dump_rsb_hash(struct dlm_ls *ls, uint32_t hash)
{
struct dlm_rsb *r;
spin_lock_bh(&ls->ls_rsbtbl_lock);
read_lock_bh(&ls->ls_rsbtbl_lock);
list_for_each_entry(r, &ls->ls_keep, res_rsbs_list) {
if (r->res_hash == hash)
dlm_dump_rsb(r);
}
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
}
void dlm_dump_rsb_name(struct dlm_ls *ls, const char *name, int len)
@ -1343,14 +1432,14 @@ void dlm_dump_rsb_name(struct dlm_ls *ls, const char *name, int len)
struct dlm_rsb *r = NULL;
int error;
spin_lock_bh(&ls->ls_rsbtbl_lock);
read_lock_bh(&ls->ls_rsbtbl_lock);
error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
if (!error)
goto out;
dlm_dump_rsb(r);
out:
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
}
static void toss_rsb(struct kref *kref)
@ -1478,6 +1567,36 @@ static void kill_lkb(struct kref *kref)
DLM_ASSERT(!lkb->lkb_status, dlm_print_lkb(lkb););
}
/* TODO move this to lib/refcount.c */
static __must_check bool
dlm_refcount_dec_and_lock_bh(refcount_t *r, spinlock_t *lock)
__cond_acquires(lock)
{
if (refcount_dec_not_one(r))
return false;
spin_lock_bh(lock);
if (!refcount_dec_and_test(r)) {
spin_unlock_bh(lock);
return false;
}
return true;
}
/* TODO move this to include/linux/kref.h */
static inline int dlm_kref_put_lock_bh(struct kref *kref,
void (*release)(struct kref *kref),
spinlock_t *lock)
{
if (dlm_refcount_dec_and_lock_bh(&kref->refcount, lock)) {
release(kref);
return 1;
}
return 0;
}
/* __put_lkb() is used when an lkb may not have an rsb attached to
it so we need to provide the lockspace explicitly */
@ -4247,14 +4366,14 @@ static void receive_remove(struct dlm_ls *ls, const struct dlm_message *ms)
memset(name, 0, sizeof(name));
memcpy(name, ms->m_extra, len);
spin_lock_bh(&ls->ls_rsbtbl_lock);
write_lock_bh(&ls->ls_rsbtbl_lock);
rv = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
if (rv) {
/* should not happen */
log_error(ls, "%s from %d not found %s", __func__,
from_nodeid, name);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
return;
}
@ -4264,14 +4383,14 @@ static void receive_remove(struct dlm_ls *ls, const struct dlm_message *ms)
log_error(ls, "receive_remove keep from %d master %d",
from_nodeid, r->res_master_nodeid);
dlm_print_rsb(r);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
return;
}
log_debug(ls, "receive_remove from %d master %d first %x %s",
from_nodeid, r->res_master_nodeid, r->res_first_lkid,
name);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
return;
}
@ -4279,14 +4398,14 @@ static void receive_remove(struct dlm_ls *ls, const struct dlm_message *ms)
log_error(ls, "receive_remove toss from %d master %d",
from_nodeid, r->res_master_nodeid);
dlm_print_rsb(r);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
return;
}
list_del(&r->res_rsbs_list);
rhashtable_remove_fast(&ls->ls_rsbtbl, &r->res_node,
dlm_rhash_rsb_params);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
free_toss_rsb(r);
}
@ -5354,7 +5473,7 @@ static struct dlm_rsb *find_grant_rsb(struct dlm_ls *ls)
{
struct dlm_rsb *r;
spin_lock_bh(&ls->ls_rsbtbl_lock);
read_lock_bh(&ls->ls_rsbtbl_lock);
list_for_each_entry(r, &ls->ls_keep, res_rsbs_list) {
if (!rsb_flag(r, RSB_RECOVER_GRANT))
continue;
@ -5363,10 +5482,10 @@ static struct dlm_rsb *find_grant_rsb(struct dlm_ls *ls)
continue;
}
hold_rsb(r);
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
return r;
}
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
return NULL;
}

View file

@ -424,7 +424,7 @@ static int new_lockspace(const char *name, const char *cluster,
INIT_LIST_HEAD(&ls->ls_toss);
INIT_LIST_HEAD(&ls->ls_keep);
spin_lock_init(&ls->ls_rsbtbl_lock);
rwlock_init(&ls->ls_rsbtbl_lock);
error = rhashtable_init(&ls->ls_rsbtbl, &dlm_rhash_rsb_params);
if (error)

View file

@ -884,7 +884,7 @@ void dlm_clear_toss(struct dlm_ls *ls)
struct dlm_rsb *r, *safe;
unsigned int count = 0;
spin_lock_bh(&ls->ls_rsbtbl_lock);
write_lock_bh(&ls->ls_rsbtbl_lock);
list_for_each_entry_safe(r, safe, &ls->ls_toss, res_rsbs_list) {
list_del(&r->res_rsbs_list);
rhashtable_remove_fast(&ls->ls_rsbtbl, &r->res_node,
@ -897,7 +897,7 @@ void dlm_clear_toss(struct dlm_ls *ls)
free_toss_rsb(r);
count++;
}
spin_unlock_bh(&ls->ls_rsbtbl_lock);
write_unlock_bh(&ls->ls_rsbtbl_lock);
if (count)
log_rinfo(ls, "dlm_clear_toss %u done", count);

View file

@ -32,7 +32,7 @@ static int dlm_create_masters_list(struct dlm_ls *ls)
goto out;
}
spin_lock_bh(&ls->ls_rsbtbl_lock);
read_lock_bh(&ls->ls_rsbtbl_lock);
list_for_each_entry(r, &ls->ls_keep, res_rsbs_list) {
if (r->res_nodeid)
continue;
@ -40,7 +40,7 @@ static int dlm_create_masters_list(struct dlm_ls *ls)
list_add(&r->res_masters_list, &ls->ls_masters_list);
dlm_hold_rsb(r);
}
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
out:
write_unlock_bh(&ls->ls_masters_lock);
return error;
@ -62,14 +62,14 @@ static void dlm_create_root_list(struct dlm_ls *ls, struct list_head *root_list)
{
struct dlm_rsb *r;
spin_lock_bh(&ls->ls_rsbtbl_lock);
read_lock_bh(&ls->ls_rsbtbl_lock);
list_for_each_entry(r, &ls->ls_keep, res_rsbs_list) {
list_add(&r->res_root_list, root_list);
dlm_hold_rsb(r);
}
WARN_ON_ONCE(!list_empty(&ls->ls_toss));
spin_unlock_bh(&ls->ls_rsbtbl_lock);
read_unlock_bh(&ls->ls_rsbtbl_lock);
}
static void dlm_release_root_list(struct list_head *root_list)