/**
* Invariant that has to be true all of the time.
*/
static int osc_lock_invariant(struct osc_lock *ols)
{
struct ldlm_lock *lock = osc_handle_ptr(&ols->ols_handle);
struct ldlm_lock *olock = ols->ols_dlmlock;
int handle_used = lustre_handle_is_used(&ols->ols_handle);
if (ergo(osc_lock_is_lockless(ols),
ols->ols_locklessable && ols->ols_dlmlock == NULL))
return 1;
/*
* If all the following "ergo"s are true, return 1, otherwise 0
*/
if (! ergo(olock != NULL, handle_used))
return 0;
if (! ergo(olock != NULL,
olock->l_handle.h_cookie == ols->ols_handle.cookie))
return 0;
if (! ergo(handle_used,
ergo(lock != NULL && olock != NULL, lock == olock) &&
ergo(lock == NULL, olock == NULL)))
return 0;
/*
* Check that ->ols_handle and ->ols_dlmlock are consistent, but
* take into account that they are set at the different time.
*/
if (! ergo(ols->ols_state == OLS_CANCELLED,
olock == NULL && !handle_used))
return 0;
/*
* DLM lock is destroyed only after we have seen cancellation
* ast.
*/
if (! ergo(olock != NULL && ols->ols_state < OLS_CANCELLED,
!ldlm_is_destroyed(olock)))
return 0;
if (! ergo(ols->ols_state == OLS_GRANTED,
olock != NULL &&
olock->l_req_mode == olock->l_granted_mode &&
ols->ols_hold))
return 0;
return 1;
}
/**
* Process a granting attempt for plain lock.
* Must be called with ns lock held.
*
* This function looks for any conflicts for \a lock in the granted or
* waiting queues. The lock is granted if no conflicts are found in
* either queue.
*
* If \a first_enq is 0 (ie, called from ldlm_reprocess_queue):
* - blocking ASTs have already been sent
*
* If \a first_enq is 1 (ie, called from ldlm_lock_enqueue):
* - blocking ASTs have not been sent yet, so list of conflicting locks
* would be collected and ASTs sent.
*/
int ldlm_process_plain_lock(struct ldlm_lock *lock, __u64 *flags,
int first_enq, enum ldlm_error *err,
struct list_head *work_list)
{
struct ldlm_resource *res = lock->l_resource;
struct list_head rpc_list;
int rc;
ENTRY;
LASSERT(lock->l_granted_mode != lock->l_req_mode);
check_res_locked(res);
LASSERT(list_empty(&res->lr_converting));
INIT_LIST_HEAD(&rpc_list);
if (!first_enq) {
LASSERT(work_list != NULL);
rc = ldlm_plain_compat_queue(&res->lr_granted, lock, NULL);
if (!rc)
RETURN(LDLM_ITER_STOP);
rc = ldlm_plain_compat_queue(&res->lr_waiting, lock, NULL);
if (!rc)
RETURN(LDLM_ITER_STOP);
ldlm_resource_unlink_lock(lock);
ldlm_grant_lock(lock, work_list);
RETURN(LDLM_ITER_CONTINUE);
}
restart:
rc = ldlm_plain_compat_queue(&res->lr_granted, lock, &rpc_list);
rc += ldlm_plain_compat_queue(&res->lr_waiting, lock, &rpc_list);
if (rc != 2) {
/* If either of the compat_queue()s returned 0, then we
* have ASTs to send and must go onto the waiting list.
*
* bug 2322: we used to unlink and re-add here, which was a
* terrible folly -- if we goto restart, we could get
* re-ordered! Causes deadlock, because ASTs aren't sent! */
if (list_empty(&lock->l_res_link))
ldlm_resource_add_lock(res, &res->lr_waiting, lock);
unlock_res(res);
rc = ldlm_run_ast_work(ldlm_res_to_ns(res), &rpc_list,
LDLM_WORK_BL_AST);
lock_res(res);
if (rc == -ERESTART) {
/* We were granted while waiting, nothing left to do */
if (lock->l_granted_mode == lock->l_req_mode)
GOTO(out, rc = 0);
/* Lock was destroyed while we were waiting, abort */
if (ldlm_is_destroyed(lock))
GOTO(out, rc = -EAGAIN);
/* Otherwise try again */
GOTO(restart, rc);
}
*flags |= LDLM_FL_BLOCK_GRANTED;
} else {
ldlm_resource_unlink_lock(lock);
ldlm_grant_lock(lock, NULL);
}
rc = 0;
out:
*err = rc;
LASSERT(list_empty(&rpc_list));
RETURN(rc);
}
