/**
* 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, ldlm_error_t *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)
GOTO(restart, rc);
*flags |= LDLM_FL_BLOCK_GRANTED;
} else {
ldlm_resource_unlink_lock(lock);
ldlm_grant_lock(lock, NULL);
}
RETURN(0);
}
/**
* Callback handler for receiving incoming completion ASTs.
*
* This only can happen on client side.
*/
static void ldlm_handle_cp_callback(struct ptlrpc_request *req,
struct ldlm_namespace *ns,
struct ldlm_request *dlm_req,
struct ldlm_lock *lock)
{
int lvb_len;
LIST_HEAD(ast_list);
int rc = 0;
LDLM_DEBUG(lock, "client completion callback handler START");
if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_CANCEL_BL_CB_RACE)) {
int to = cfs_time_seconds(1);
while (to > 0) {
schedule_timeout_and_set_state(
TASK_INTERRUPTIBLE, to);
if (lock->l_granted_mode == lock->l_req_mode ||
lock->l_flags & LDLM_FL_DESTROYED)
break;
}
}
lvb_len = req_capsule_get_size(&req->rq_pill, &RMF_DLM_LVB, RCL_CLIENT);
if (lvb_len < 0) {
LDLM_ERROR(lock, "Fail to get lvb_len, rc = %d", lvb_len);
GOTO(out, rc = lvb_len);
} else if (lvb_len > 0) {
if (lock->l_lvb_len > 0) {
/* for extent lock, lvb contains ost_lvb{}. */
LASSERT(lock->l_lvb_data != NULL);
if (unlikely(lock->l_lvb_len < lvb_len)) {
LDLM_ERROR(lock, "Replied LVB is larger than "
"expectation, expected = %d, "
"replied = %d",
lock->l_lvb_len, lvb_len);
GOTO(out, rc = -EINVAL);
}
} else if (ldlm_has_layout(lock)) { /* for layout lock, lvb has
* variable length */
void *lvb_data;
OBD_ALLOC(lvb_data, lvb_len);
if (lvb_data == NULL) {
LDLM_ERROR(lock, "No memory: %d.\n", lvb_len);
GOTO(out, rc = -ENOMEM);
}
lock_res_and_lock(lock);
LASSERT(lock->l_lvb_data == NULL);
lock->l_lvb_data = lvb_data;
lock->l_lvb_len = lvb_len;
unlock_res_and_lock(lock);
}
}
lock_res_and_lock(lock);
if ((lock->l_flags & LDLM_FL_DESTROYED) ||
lock->l_granted_mode == lock->l_req_mode) {
/* bug 11300: the lock has already been granted */
unlock_res_and_lock(lock);
LDLM_DEBUG(lock, "Double grant race happened");
GOTO(out, rc = 0);
}
/* If we receive the completion AST before the actual enqueue returned,
* then we might need to switch lock modes, resources, or extents. */
if (dlm_req->lock_desc.l_granted_mode != lock->l_req_mode) {
lock->l_req_mode = dlm_req->lock_desc.l_granted_mode;
LDLM_DEBUG(lock, "completion AST, new lock mode");
}
if (lock->l_resource->lr_type != LDLM_PLAIN) {
ldlm_convert_policy_to_local(req->rq_export,
dlm_req->lock_desc.l_resource.lr_type,
&dlm_req->lock_desc.l_policy_data,
&lock->l_policy_data);
LDLM_DEBUG(lock, "completion AST, new policy data");
}
ldlm_resource_unlink_lock(lock);
if (memcmp(&dlm_req->lock_desc.l_resource.lr_name,
&lock->l_resource->lr_name,
sizeof(lock->l_resource->lr_name)) != 0) {
unlock_res_and_lock(lock);
rc = ldlm_lock_change_resource(ns, lock,
&dlm_req->lock_desc.l_resource.lr_name);
if (rc < 0) {
LDLM_ERROR(lock, "Failed to allocate resource");
GOTO(out, rc);
}
LDLM_DEBUG(lock, "completion AST, new resource");
CERROR("change resource!\n");
lock_res_and_lock(lock);
}
if (dlm_req->lock_flags & LDLM_FL_AST_SENT) {
/* BL_AST locks are not needed in LRU.
* Let ldlm_cancel_lru() be fast. */
ldlm_lock_remove_from_lru(lock);
lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_BL_AST;
LDLM_DEBUG(lock, "completion AST includes blocking AST");
}
if (lock->l_lvb_len > 0) {
rc = ldlm_fill_lvb(lock, &req->rq_pill, RCL_CLIENT,
lock->l_lvb_data, lvb_len);
if (rc < 0) {
unlock_res_and_lock(lock);
GOTO(out, rc);
}
}
ldlm_grant_lock(lock, &ast_list);
unlock_res_and_lock(lock);
LDLM_DEBUG(lock, "callback handler finished, about to run_ast_work");
/* Let Enqueue to call osc_lock_upcall() and initialize
* l_ast_data */
OBD_FAIL_TIMEOUT(OBD_FAIL_OSC_CP_ENQ_RACE, 2);
ldlm_run_ast_work(ns, &ast_list, LDLM_WORK_CP_AST);
LDLM_DEBUG_NOLOCK("client completion callback handler END (lock %p)",
lock);
GOTO(out, rc);
out:
if (rc < 0) {
lock_res_and_lock(lock);
lock->l_flags |= LDLM_FL_FAILED;
unlock_res_and_lock(lock);
wake_up(&lock->l_waitq);
}
LDLM_LOCK_RELEASE(lock);
}
