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LU-13128 osc: glimpse and lock cancel race
[fs/lustre-release.git] / lustre / ldlm / ldlm_inodebits.c
index d6ededf..095c6e5 100644 (file)
 #include "ldlm_internal.h"
 
 #ifdef HAVE_SERVER_SUPPORT
-/*
- * local lock will be canceled after use, and it should run blocking ast only
- * when it should trigger Commit-on-Sharing, otherwise if the blocking ast
- * is run and does nothing, it will prevent subsequent operations to trigger
- * Commit-on-Sharing, see LU-11102.
+
+/**
+ * It should iterate through all waiting locks on a given resource queue and
+ * attempt to grant them. An optimization is to check only heads waitintg
+ * locks for each inodebit type.
+ *
+ * Must be called with resource lock held.
  */
-static bool ldlm_should_run_bl_ast(const struct ldlm_lock *lock,
-                                  const struct ldlm_lock *req)
+int ldlm_reprocess_inodebits_queue(struct ldlm_resource *res,
+                                  struct list_head *queue,
+                                  struct list_head *work_list,
+                                  enum ldlm_process_intention intention,
+                                  struct ldlm_lock *hint)
 {
-       /* no blocking ast */
-       if (!lock->l_blocking_ast)
-               return false;
+       __u64 flags;
+       int rc = LDLM_ITER_CONTINUE;
+       enum ldlm_error err;
+       LIST_HEAD(bl_ast_list);
+       struct ldlm_ibits_queues *queues = res->lr_ibits_queues;
+       int i;
+
+       ENTRY;
+
+       check_res_locked(res);
+
+       LASSERT(res->lr_type == LDLM_IBITS);
+       LASSERT(intention == LDLM_PROCESS_RESCAN ||
+               intention == LDLM_PROCESS_RECOVERY);
+
+       if (intention == LDLM_PROCESS_RECOVERY)
+               return ldlm_reprocess_queue(res, queue, work_list, intention,
+                                           NULL);
 
-       /* not local lock */
-       if (!ldlm_is_local(lock))
-               return true;
+restart:
+       CDEBUG(D_DLMTRACE, "--- Reprocess resource "DLDLMRES" (%p)\n",
+              PLDLMRES(res), res);
+
+       for (i = 0; i < MDS_INODELOCK_NUMBITS; i++) {
+               LIST_HEAD(rpc_list);
+               struct list_head *head = &queues->liq_waiting[i];
+               struct ldlm_lock *pending;
+               struct ldlm_ibits_node *node;
+
+               if (list_empty(head))
+                       continue;
+               if (hint && !(hint->l_policy_data.l_inodebits.bits & (1 << i)))
+                       continue;
+
+               node = list_entry(head->next, struct ldlm_ibits_node,
+                                 lin_link[i]);
+
+               pending = node->lock;
+               LDLM_DEBUG(pending, "Reprocessing lock from queue %d", i);
+
+               flags = 0;
+               rc = ldlm_process_inodebits_lock(pending, &flags, intention,
+                                                &err, &rpc_list);
+               if (ldlm_is_granted(pending)) {
+                       list_splice(&rpc_list, work_list);
+                       /* Try to grant more locks from current queue */
+                       i--;
+               } else {
+                       list_splice(&rpc_list, &bl_ast_list);
+               }
+       }
 
-       /* should trigger Commit-on-Sharing */
-       if ((lock->l_req_mode & LCK_COS))
-               return true;
+       if (!list_empty(&bl_ast_list)) {
+               unlock_res(res);
 
-       /* local read lock will be canceld after use */
-       if (!(lock->l_req_mode & (LCK_PW | LCK_EX)))
-               return false;
+               rc = ldlm_run_ast_work(ldlm_res_to_ns(res), &bl_ast_list,
+                                      LDLM_WORK_BL_AST);
 
-       /* if CoS enabled, check if @req is from different client */
-       if (ldlm_is_cos_enabled(req))
-               return lock->l_client_cookie != req->l_client_cookie;
+               lock_res(res);
+               if (rc == -ERESTART)
+                       GOTO(restart, rc);
+       }
 
-       /* check if @req is COS incompatible */
-       if (ldlm_is_cos_incompat(req))
-               return true;
+       if (!list_empty(&bl_ast_list))
+               ldlm_discard_bl_list(&bl_ast_list);
 
-       return false;
+       RETURN(rc);
 }
 
 /**
@@ -204,12 +251,12 @@ ldlm_inodebits_compat_queue(struct list_head *queue, struct ldlm_lock *req,
 
                                /* Add locks of the policy group to @work_list
                                 * as blocking locks for @req */
-                               if (ldlm_should_run_bl_ast(lock, req))
+                               if (lock->l_blocking_ast)
                                        ldlm_add_ast_work_item(lock, req,
                                                               work_list);
                                head = &lock->l_sl_policy;
                                list_for_each_entry(lock, head, l_sl_policy)
-                                       if (ldlm_should_run_bl_ast(lock, req))
+                                       if (lock->l_blocking_ast)
                                                ldlm_add_ast_work_item(lock,
                                                                req, work_list);
                        }
@@ -245,7 +292,7 @@ int ldlm_process_inodebits_lock(struct ldlm_lock *lock, __u64 *flags,
 
        ENTRY;
 
-       LASSERT(lock->l_granted_mode != lock->l_req_mode);
+       LASSERT(!ldlm_is_granted(lock));
        check_res_locked(res);
 
        if (intention == LDLM_PROCESS_RESCAN) {
@@ -335,7 +382,10 @@ void ldlm_ibits_policy_wire_to_local(const union ldlm_wire_policy_data *wpolicy,
                                     union ldlm_policy_data *lpolicy)
 {
        lpolicy->l_inodebits.bits = wpolicy->l_inodebits.bits;
-       lpolicy->l_inodebits.try_bits = wpolicy->l_inodebits.try_bits;
+       /**
+        * try_bits are to be handled outside of generic write_to_local due
+        * to different behavior on a server and client.
+        */
 }
 
 void ldlm_ibits_policy_local_to_wire(const union ldlm_policy_data *lpolicy,
@@ -377,89 +427,151 @@ int ldlm_inodebits_drop(struct ldlm_lock *lock, __u64 to_drop)
 EXPORT_SYMBOL(ldlm_inodebits_drop);
 
 /* convert single lock */
-int ldlm_cli_dropbits(struct ldlm_lock *lock, __u64 drop_bits)
+int ldlm_cli_inodebits_convert(struct ldlm_lock *lock,
+                              enum ldlm_cancel_flags cancel_flags)
 {
-       struct lustre_handle lockh;
+       struct ldlm_namespace *ns = ldlm_lock_to_ns(lock);
+       struct ldlm_lock_desc ld = { { 0 } };
+       __u64 drop_bits, new_bits;
        __u32 flags = 0;
        int rc;
 
        ENTRY;
 
-       LASSERT(drop_bits);
-       LASSERT(!lock->l_readers && !lock->l_writers);
+       check_res_locked(lock->l_resource);
 
-       LDLM_DEBUG(lock, "client lock convert START");
+       /* Lock is being converted already */
+       if (ldlm_is_converting(lock)) {
+               if (!(cancel_flags & LCF_ASYNC)) {
+                       struct l_wait_info lwi = { 0 };
 
-       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);
+                       unlock_res_and_lock(lock);
+                       l_wait_event(lock->l_waitq,
+                                    is_lock_converted(lock), &lwi);
+                       lock_res_and_lock(lock);
+               }
+               RETURN(0);
        }
 
-       /* 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);
-       }
+       /* lru_cancel may happen in parallel and call ldlm_cli_cancel_list()
+        * independently.
+        */
+       if (ldlm_is_canceling(lock))
+               RETURN(-EINVAL);
 
-       /* 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);
-       }
+       /* no need in only local convert */
+       if (lock->l_flags & (LDLM_FL_LOCAL_ONLY | LDLM_FL_CANCEL_ON_BLOCK))
+               RETURN(-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);
+       drop_bits = lock->l_policy_data.l_inodebits.cancel_bits;
+       /* no cancel bits - means that caller needs full cancel */
+       if (drop_bits == 0)
+               RETURN(-EINVAL);
+
+       new_bits = lock->l_policy_data.l_inodebits.bits & ~drop_bits;
+       /* check if all lock bits are dropped, proceed with cancel */
+       if (!new_bits)
+               RETURN(-EINVAL);
+
+       /* check if no dropped bits, consider this as successful convert */
+       if (lock->l_policy_data.l_inodebits.bits == new_bits)
+               RETURN(0);
 
-       /* 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);
-
+       ld.l_policy_data.l_inodebits.cancel_bits = drop_bits;
+       unlock_res_and_lock(lock);
+       lock->l_blocking_ast(lock, &ld, 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);
+       rc = ldlm_cli_convert_req(lock, &flags, new_bits);
+       lock_res_and_lock(lock);
+       if (rc)
+               GOTO(full_cancel, rc);
+
+       /* Finally clear these bits in lock ibits */
+       ldlm_inodebits_drop(lock, drop_bits);
+
+       /* Being locked again check if lock was canceled, it is important
+        * to do and don't drop cbpending below
+        */
+       if (ldlm_is_canceling(lock))
+               GOTO(full_cancel, rc = -EINVAL);
+
+       /* also check again if more bits to be cancelled appeared */
+       if (drop_bits != lock->l_policy_data.l_inodebits.cancel_bits)
+               GOTO(clear_converting, rc = -EAGAIN);
+
+       /* 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);
+       spin_lock(&ns->ns_lock);
+       if (list_empty(&lock->l_lru))
+               ldlm_lock_add_to_lru_nolock(lock);
+       spin_unlock(&ns->ns_lock);
+
+       /* the job is done, zero the cancel_bits. If more conflicts appear,
+        * it will result in another cycle of ldlm_cli_inodebits_convert().
+        */
+full_cancel:
+       lock->l_policy_data.l_inodebits.cancel_bits = 0;
+clear_converting:
+       ldlm_clear_converting(lock);
+       RETURN(rc);
+}
+
+int ldlm_inodebits_alloc_lock(struct ldlm_lock *lock)
+{
+       if (ldlm_is_ns_srv(lock)) {
+               int i;
+
+               OBD_SLAB_ALLOC_PTR(lock->l_ibits_node, ldlm_inodebits_slab);
+               if (lock->l_ibits_node == NULL)
+                       return -ENOMEM;
+               for (i = 0; i < MDS_INODELOCK_NUMBITS; i++)
+                       INIT_LIST_HEAD(&lock->l_ibits_node->lin_link[i]);
+               lock->l_ibits_node->lock = lock;
+       } else {
+               lock->l_ibits_node = NULL;
+       }
+       return 0;
+}
+
+void ldlm_inodebits_add_lock(struct ldlm_resource *res, struct list_head *head,
+                            struct ldlm_lock *lock)
+{
+       int i;
+
+       if (!ldlm_is_ns_srv(lock))
+               return;
+
+       if (head == &res->lr_waiting) {
+               for (i = 0; i < MDS_INODELOCK_NUMBITS; i++) {
+                       if (lock->l_policy_data.l_inodebits.bits & (1 << i))
+                               list_add_tail(&lock->l_ibits_node->lin_link[i],
+                                       &res->lr_ibits_queues->liq_waiting[i]);
                }
-               unlock_res_and_lock(lock);
-               GOTO(exit, rc);
+       } else if (head == &res->lr_granted && lock->l_ibits_node != NULL) {
+               for (i = 0; i < MDS_INODELOCK_NUMBITS; i++)
+                       LASSERT(list_empty(&lock->l_ibits_node->lin_link[i]));
+               OBD_SLAB_FREE_PTR(lock->l_ibits_node, ldlm_inodebits_slab);
+               lock->l_ibits_node = NULL;
        }
-       EXIT;
-exit:
-       LDLM_DEBUG(lock, "client lock convert END");
-       return rc;
+}
+
+void ldlm_inodebits_unlink_lock(struct ldlm_lock *lock)
+{
+       int i;
+
+       ldlm_unlink_lock_skiplist(lock);
+       if (!ldlm_is_ns_srv(lock))
+               return;
+
+       for (i = 0; i < MDS_INODELOCK_NUMBITS; i++)
+               list_del_init(&lock->l_ibits_node->lin_link[i]);
 }