-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* GPL HEADER END
*/
/*
- * Copyright 2008 Sun Microsystems, Inc. All rights reserved
+ * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
+ *
+ * Copyright (c) 2011, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
* Author: Phil Schwan <phil@clusterfs.com>
*/
+/**
+ * This file contains implementation of PLAIN lock type.
+ *
+ * PLAIN locks are the simplest form of LDLM locking, and are used when
+ * there only needs to be a single lock on a resource. This avoids some
+ * of the complexity of EXTENT and IBITS lock types, but doesn't allow
+ * different "parts" of a resource to be locked concurrently. Example
+ * use cases for PLAIN locks include locking of MGS configuration logs
+ * and (as of Lustre 2.4) quota records.
+ */
+
#define DEBUG_SUBSYSTEM S_LDLM
#ifdef __KERNEL__
#include "ldlm_internal.h"
+#ifdef HAVE_SERVER_SUPPORT
+/**
+ * Determine if the lock is compatible with all locks on the queue.
+ *
+ * If \a work_list is provided, conflicting locks are linked there.
+ * If \a work_list is not provided, we exit this function on first conflict.
+ *
+ * \retval 0 if there are conflicting locks in the \a queue
+ * \retval 1 if the lock is compatible to all locks in \a queue
+ */
static inline int
ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
- struct list_head *work_list)
+ struct list_head *work_list)
{
- struct list_head *tmp;
- struct ldlm_lock *lock;
- ldlm_mode_t req_mode = req->l_req_mode;
- int compat = 1;
- 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);
-
- /* last lock in mode group */
- tmp = &list_entry(lock->l_sl_mode.prev,
- struct ldlm_lock,
- l_sl_mode)->l_res_link;
-
- if (lockmode_compat(lock->l_req_mode, req_mode))
+ ldlm_mode_t req_mode = req->l_req_mode;
+ struct ldlm_lock *lock;
+ struct list_head *tmp;
+ int compat = 1;
+ ENTRY;
+
+ lockmode_verify(req_mode);
+
+ list_for_each_entry(lock, queue, l_res_link) {
+ /* We stop walking the queue if we hit ourselves so we don't
+ * take conflicting locks enqueued after us into account,
+ * or we'd wait forever. */
+ if (req == lock)
+ RETURN(compat);
+
+ /* Advance loop cursor to last lock of mode group. */
+ tmp = &list_entry(lock->l_sl_mode.prev, struct ldlm_lock,
+ l_sl_mode)->l_res_link;
+
+ if (lockmode_compat(lock->l_req_mode, req_mode))
continue;
if (!work_list)
compat = 0;
- /* add locks of the mode group to @work_list as
- * blocking locks for @req */
+ /* Add locks of the mode group to \a work_list as
+ * blocking locks for \a req. */
if (lock->l_blocking_ast)
ldlm_add_ast_work_item(lock, req, work_list);
{
- struct list_head *head;
+ struct list_head *head;
head = &lock->l_sl_mode;
- list_for_each_entry(lock, head, l_sl_mode)
+ list_for_each_entry(lock, head, l_sl_mode)
if (lock->l_blocking_ast)
ldlm_add_ast_work_item(lock, req,
work_list);
RETURN(compat);
}
-/* If first_enq is 0 (ie, called from ldlm_reprocess_queue):
+/**
+ * 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
- * - must call this function with the resource lock held
*
- * If first_enq is 1 (ie, called from ldlm_lock_enqueue):
- * - blocking ASTs have not been sent
- * - must call this function with the resource lock held */
-int ldlm_process_plain_lock(struct ldlm_lock *lock, int *flags, int first_enq,
- ldlm_error_t *err, struct list_head *work_list)
+ * 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;
- CFS_LIST_HEAD(rpc_list);
- int rc;
- ENTRY;
+ struct ldlm_resource *res = lock->l_resource;
+ struct list_head rpc_list;
+ int rc;
+ ENTRY;
- check_res_locked(res);
- LASSERT(list_empty(&res->lr_converting));
+ 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);
* 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))
+ if (list_empty(&lock->l_res_link))
ldlm_resource_add_lock(res, &res->lr_waiting, lock);
unlock_res(res);
- rc = ldlm_run_ast_work(&rpc_list, LDLM_WORK_BL_AST);
+ rc = ldlm_run_ast_work(ldlm_res_to_ns(res), &rpc_list,
+ LDLM_WORK_BL_AST);
lock_res(res);
- if (rc == -ERESTART)
- GOTO(restart, -ERESTART);
+ if (rc == -ERESTART)
+ GOTO(restart, rc);
*flags |= LDLM_FL_BLOCK_GRANTED;
} else {
ldlm_resource_unlink_lock(lock);
}
RETURN(0);
}
+#endif /* HAVE_SERVER_SUPPORT */
+
+void ldlm_plain_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
+ ldlm_policy_data_t *lpolicy)
+{
+ /* No policy for plain locks */
+}
+
+void ldlm_plain_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
+ ldlm_wire_policy_data_t *wpolicy)
+{
+ /* No policy for plain locks */
+}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff