+ wpolicy->l_inodebits.try_bits = lpolicy->l_inodebits.try_bits;
+}
+
+/**
+ * Attempt to convert already granted IBITS lock with several bits set to
+ * a lock with less bits (downgrade).
+ *
+ * Such lock conversion is used to keep lock with non-blocking bits instead of
+ * cancelling it, introduced for better support of DoM files.
+ */
+int ldlm_inodebits_drop(struct ldlm_lock *lock, __u64 to_drop)
+{
+ ENTRY;
+
+ check_res_locked(lock->l_resource);
+
+ /* Just return if there are no conflicting bits */
+ if ((lock->l_policy_data.l_inodebits.bits & to_drop) == 0) {
+ LDLM_WARN(lock, "try to drop unset bits %#llx/%#llx",
+ lock->l_policy_data.l_inodebits.bits, to_drop);
+ /* nothing to do */
+ RETURN(0);
+ }
+
+ /* remove lock from a skiplist and put in the new place
+ * according with new inodebits */
+ ldlm_resource_unlink_lock(lock);
+ lock->l_policy_data.l_inodebits.bits &= ~to_drop;
+ ldlm_grant_lock_with_skiplist(lock);
+ RETURN(0);
+}
+EXPORT_SYMBOL(ldlm_inodebits_drop);
+
+/* convert single lock */
+int ldlm_cli_dropbits(struct ldlm_lock *lock, __u64 drop_bits)
+{
+ struct lustre_handle lockh;
+ __u32 flags = 0;
+ int rc;
+
+ ENTRY;
+
+ LASSERT(drop_bits);
+ LASSERT(!lock->l_readers && !lock->l_writers);
+
+ LDLM_DEBUG(lock, "client lock convert START");
+
+ ldlm_lock2handle(lock, &lockh);
+ lock_res_and_lock(lock);
+ /* check if all bits are blocked */
+ if (!(lock->l_policy_data.l_inodebits.bits & ~drop_bits)) {
+ unlock_res_and_lock(lock);
+ /* return error to continue with cancel */
+ GOTO(exit, rc = -EINVAL);
+ }
+
+ /* check if no common bits, consider this as successful convert */
+ if (!(lock->l_policy_data.l_inodebits.bits & drop_bits)) {
+ unlock_res_and_lock(lock);
+ GOTO(exit, rc = 0);
+ }
+
+ /* check if there is race with cancel */
+ if (ldlm_is_canceling(lock) || ldlm_is_cancel(lock)) {
+ unlock_res_and_lock(lock);
+ GOTO(exit, rc = -EINVAL);
+ }
+
+ /* clear cbpending flag early, it is safe to match lock right after
+ * client convert because it is downgrade always.
+ */
+ ldlm_clear_cbpending(lock);
+ ldlm_clear_bl_ast(lock);
+
+ /* If lock is being converted already, check drop bits first */
+ if (ldlm_is_converting(lock)) {
+ /* raced lock convert, lock inodebits are remaining bits
+ * so check if they are conflicting with new convert or not.
+ */
+ if (!(lock->l_policy_data.l_inodebits.bits & drop_bits)) {
+ unlock_res_and_lock(lock);
+ GOTO(exit, rc = 0);
+ }
+ /* Otherwise drop new conflicting bits in new convert */
+ }
+ ldlm_set_converting(lock);
+ /* from all bits of blocking lock leave only conflicting */
+ drop_bits &= lock->l_policy_data.l_inodebits.bits;
+ /* save them in cancel_bits, so l_blocking_ast will know
+ * which bits from the current lock were dropped. */
+ lock->l_policy_data.l_inodebits.cancel_bits = drop_bits;
+ /* Finally clear these bits in lock ibits */
+ ldlm_inodebits_drop(lock, drop_bits);
+ unlock_res_and_lock(lock);
+ /* Finally call cancel callback for remaining bits only.
+ * It is important to have converting flag during that
+ * so blocking_ast callback can distinguish convert from
+ * cancels.
+ */
+ if (lock->l_blocking_ast)
+ lock->l_blocking_ast(lock, NULL, lock->l_ast_data,
+ LDLM_CB_CANCELING);
+
+ /* now notify server about convert */
+ rc = ldlm_cli_convert(lock, &flags);
+ if (rc) {
+ lock_res_and_lock(lock);
+ if (ldlm_is_converting(lock)) {
+ ldlm_clear_converting(lock);
+ ldlm_set_cbpending(lock);
+ ldlm_set_bl_ast(lock);
+ }
+ unlock_res_and_lock(lock);
+ GOTO(exit, rc);
+ }
+ EXIT;
+exit:
+ LDLM_DEBUG(lock, "client lock convert END");
+ return rc;