[DLM] fix grant_after_purge softlockup
In dlm_grant_after_purge() we were holding a hash table read_lock while
calling put_rsb() which potentially removes the rsb from the hash table,
taking the same lock in write. Fix this by flagging rsb's ahead of time
that have been purged. Then iteratively read_lock the hash table, find a
flagged rsb, unlock, process rsb.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index c329902..149106f 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -280,6 +280,7 @@
RSB_NEW_MASTER,
RSB_NEW_MASTER2,
RSB_RECOVER_CONVERT,
+ RSB_LOCKS_PURGED,
};
static inline void rsb_set_flag(struct dlm_rsb *r, enum rsb_flags flag)
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 85a0e73..5f69639 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -3278,6 +3278,7 @@
list_for_each_entry_safe(lkb, safe, queue, lkb_statequeue) {
if (test(ls, lkb)) {
+ rsb_set_flag(r, RSB_LOCKS_PURGED);
del_lkb(r, lkb);
/* this put should free the lkb */
if (!dlm_put_lkb(lkb))
@@ -3334,27 +3335,40 @@
return 0;
}
-int dlm_grant_after_purge(struct dlm_ls *ls)
+static struct dlm_rsb *find_purged_rsb(struct dlm_ls *ls, int bucket)
+{
+ struct dlm_rsb *r, *r_ret = NULL;
+
+ read_lock(&ls->ls_rsbtbl[bucket].lock);
+ list_for_each_entry(r, &ls->ls_rsbtbl[bucket].list, res_hashchain) {
+ if (!rsb_flag(r, RSB_LOCKS_PURGED))
+ continue;
+ hold_rsb(r);
+ rsb_clear_flag(r, RSB_LOCKS_PURGED);
+ r_ret = r;
+ break;
+ }
+ read_unlock(&ls->ls_rsbtbl[bucket].lock);
+ return r_ret;
+}
+
+void dlm_grant_after_purge(struct dlm_ls *ls)
{
struct dlm_rsb *r;
int i;
for (i = 0; i < ls->ls_rsbtbl_size; i++) {
- read_lock(&ls->ls_rsbtbl[i].lock);
- list_for_each_entry(r, &ls->ls_rsbtbl[i].list, res_hashchain) {
- hold_rsb(r);
- lock_rsb(r);
- if (is_master(r)) {
- grant_pending_locks(r);
- confirm_master(r, 0);
- }
- unlock_rsb(r);
- put_rsb(r);
+ r = find_purged_rsb(ls, i);
+ if (!r)
+ continue;
+ lock_rsb(r);
+ if (is_master(r)) {
+ grant_pending_locks(r);
+ confirm_master(r, 0);
}
- read_unlock(&ls->ls_rsbtbl[i].lock);
+ unlock_rsb(r);
+ put_rsb(r);
}
-
- return 0;
}
static struct dlm_lkb *search_remid_list(struct list_head *head, int nodeid,
diff --git a/fs/dlm/lock.h b/fs/dlm/lock.h
index bffab9c..56cdc073 100644
--- a/fs/dlm/lock.h
+++ b/fs/dlm/lock.h
@@ -25,7 +25,7 @@
int dlm_purge_locks(struct dlm_ls *ls);
void dlm_purge_mstcpy_locks(struct dlm_rsb *r);
-int dlm_grant_after_purge(struct dlm_ls *ls);
+void dlm_grant_after_purge(struct dlm_ls *ls);
int dlm_recover_waiters_post(struct dlm_ls *ls);
void dlm_recover_waiters_pre(struct dlm_ls *ls);
int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc);