+/* Determine if the lock is compatible with all locks on the queue.
+ * We stop walking the queue if we hit ourselves so we don't take
+ * conflicting locks enqueued after us into accound, or we'd wait forever.
+ *
+ * 0 if the lock is not compatible
+ * 1 if the lock is compatible
+ * 2 if this group lock is compatible and requires no further checking
+ * negative error, such as EWOULDBLOCK for group locks
+ */
+static int
+ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
+ int send_cbs, int *flags, ldlm_error_t *err)
+{
+ struct list_head *tmp;
+ struct ldlm_lock *lock;
+ ldlm_mode_t req_mode = req->l_req_mode;
+ __u64 req_start = req->l_req_extent.start;
+ __u64 req_end = req->l_req_extent.end;
+ int compat = 1;
+ int scan = 0;
+ ENTRY;
+
+ lockmode_verify(req_mode);
+
+ list_for_each(tmp, queue) {
+ lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+
+ if (req == lock)
+ RETURN(compat);
+
+ if (scan) {
+ /* We only get here if we are queuing GROUP lock
+ and met some incompatible one. The main idea of this
+ code is to insert GROUP lock past compatible GROUP
+ lock in the waiting queue or if there is not any,
+ then in front of first non-GROUP lock */
+ if (lock->l_req_mode != LCK_GROUP) {
+ /* Ok, we hit non-GROUP lock, there should be no
+ more GROUP locks later on, queue in front of
+ first non-GROUP lock */
+
+ ldlm_resource_insert_lock_after(lock, req);
+ list_del_init(&lock->l_res_link);
+ ldlm_resource_insert_lock_after(req, lock);
+ RETURN(0);
+ }
+ if (req->l_policy_data.l_extent.gid ==
+ lock->l_policy_data.l_extent.gid) {
+ /* found it */
+ ldlm_resource_insert_lock_after(lock,
+ req);
+ RETURN(0);
+ }
+ continue;
+ }
+
+ /* locks are compatible, overlap doesn't matter */
+ if (lockmode_compat(lock->l_req_mode, req_mode)) {
+ /* non-group locks are compatible, overlap doesn't
+ matter */
+ if (req_mode != LCK_GROUP)
+ continue;
+
+ /* If we are trying to get a GROUP lock and there is
+ another one of this kind, we need to compare gid */
+ if (req->l_policy_data.l_extent.gid ==
+ lock->l_policy_data.l_extent.gid) {
+ if (lock->l_req_mode == lock->l_granted_mode)
+ RETURN(2);
+
+ /* If we are in nonblocking mode - return
+ immediately */
+ if (*flags & LDLM_FL_BLOCK_NOWAIT) {
+ compat = -EWOULDBLOCK;
+ goto destroylock;
+ }
+ /* If this group lock is compatible with another
+ * group lock on the waiting list, they must be
+ * together in the list, so they can be granted
+ * at the same time. Otherwise the later lock
+ * can get stuck behind another, incompatible,
+ * lock. */
+ ldlm_resource_insert_lock_after(lock, req);
+ /* Because 'lock' is not granted, we can stop
+ * processing this queue and return immediately.
+ * There is no need to check the rest of the
+ * list. */
+ RETURN(0);
+ }
+ }
+
+ if (req_mode == LCK_GROUP &&
+ (lock->l_req_mode != lock->l_granted_mode)) {
+ scan = 1;
+ compat = 0;
+ if (lock->l_req_mode != LCK_GROUP) {
+ /* Ok, we hit non-GROUP lock, there should be no
+ more GROUP locks later on, queue in front of
+ first non-GROUP lock */
+
+ ldlm_resource_insert_lock_after(lock, req);
+ list_del_init(&lock->l_res_link);
+ ldlm_resource_insert_lock_after(req, lock);
+ RETURN(0);
+ }
+ if (req->l_policy_data.l_extent.gid ==
+ lock->l_policy_data.l_extent.gid) {
+ /* found it */
+ ldlm_resource_insert_lock_after(lock, req);
+ RETURN(0);
+ }
+ continue;
+ }
+
+ if (lock->l_req_mode == LCK_GROUP) {
+ /* If compared lock is GROUP, then requested is PR/PW/=>
+ * this is not compatible; extent range does not
+ * matter */
+ if (*flags & LDLM_FL_BLOCK_NOWAIT) {
+ compat = -EWOULDBLOCK;
+ goto destroylock;
+ } else {
+ *flags |= LDLM_FL_NO_TIMEOUT;
+ }
+ } else if (lock->l_policy_data.l_extent.end < req_start ||
+ lock->l_policy_data.l_extent.start > req_end) {
+ /* if a non grouplock doesn't overlap skip it */
+ continue;
+ }
+
+ if (!send_cbs)
+ RETURN(0);
+
+ compat = 0;
+ if (lock->l_blocking_ast)
+ ldlm_add_ast_work_item(lock, req, NULL, 0);
+ }
+
+ return(compat);
+destroylock:
+ list_del_init(&req->l_res_link);
+ ldlm_lock_destroy(req);
+ *err = compat;
+ RETURN(compat);
+}
+
+/* If first_enq is 0 (ie, called from ldlm_reprocess_queue):
+ * - blocking ASTs have already been sent
+ * - the caller has already initialized req->lr_tmp
+ * - must call this function with the ns lock held
+ *
+ * If first_enq is 1 (ie, called from ldlm_lock_enqueue):
+ * - blocking ASTs have not been sent
+ * - the caller has NOT initialized req->lr_tmp, so we must
+ * - must call this function with the ns lock held once */
+int ldlm_process_extent_lock(struct ldlm_lock *lock, int *flags, int first_enq,
+ ldlm_error_t *err)