-/* -*- 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.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
*
* GPL HEADER END
*/
* Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
- * Copyright (c) 2011 Whamcloud, Inc.
- *
+ * Copyright (c) 2011, 2017, 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 <lustre_dlm.h>
#include <obd_support.h>
#include <lustre_lib.h>
-#else
-#include <liblustre.h>
-#endif
#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(cfs_list_t *queue, struct ldlm_lock *req,
- cfs_list_t *work_list)
+ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
+ struct list_head *work_list)
{
- cfs_list_t *tmp;
- struct ldlm_lock *lock;
- ldlm_mode_t req_mode = req->l_req_mode;
- int compat = 1;
- ENTRY;
+ enum ldlm_mode req_mode = req->l_req_mode;
+ struct ldlm_lock *lock, *next_lock;
+ int compat = 1;
+ ENTRY;
- lockmode_verify(req_mode);
+ lockmode_verify(req_mode);
- cfs_list_for_each(tmp, queue) {
- lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
+ list_for_each_entry_safe(lock, next_lock, queue, l_res_link) {
- if (req == lock)
- RETURN(compat);
+ /* 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);
- /* last lock in mode group */
- tmp = &cfs_list_entry(lock->l_sl_mode.prev,
- struct ldlm_lock,
- l_sl_mode)->l_res_link;
+ /* Advance loop cursor to last lock of mode group. */
+ next_lock = list_entry(list_entry(lock->l_sl_mode.prev,
+ struct ldlm_lock,
+ l_sl_mode)->l_res_link.next,
+ struct ldlm_lock, l_res_link);
- if (lockmode_compat(lock->l_req_mode, req_mode))
+ 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);
{
- cfs_list_t *head;
+ struct list_head *head;
head = &lock->l_sl_mode;
- cfs_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):
- * - blocking ASTs have already been sent
- * - must call this function with the resource lock held
+/**
+ * Process a granting attempt for plain lock.
+ * Must be called with ns 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, cfs_list_t *work_list)
+ * 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.
+ */
+int ldlm_process_plain_lock(struct ldlm_lock *lock, __u64 *flags,
+ enum ldlm_process_intention intention,
+ enum ldlm_error *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 *grant_work = intention == LDLM_PROCESS_ENQUEUE ?
+ NULL : work_list;
+ int rc;
+ ENTRY;
- check_res_locked(res);
- LASSERT(cfs_list_empty(&res->lr_converting));
+ LASSERT(lock->l_granted_mode != lock->l_req_mode);
+ check_res_locked(res);
+ *err = ELDLM_OK;
- if (!first_enq) {
+ if (intention == LDLM_PROCESS_RESCAN) {
LASSERT(work_list != NULL);
rc = ldlm_plain_compat_queue(&res->lr_granted, lock, NULL);
if (!rc)
RETURN(LDLM_ITER_STOP);
ldlm_resource_unlink_lock(lock);
- ldlm_grant_lock(lock, work_list);
+ ldlm_grant_lock(lock, grant_work);
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 (cfs_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, -ERESTART);
- *flags |= LDLM_FL_BLOCK_GRANTED;
- } else {
- ldlm_resource_unlink_lock(lock);
- ldlm_grant_lock(lock, NULL);
- }
- RETURN(0);
+ rc = ldlm_plain_compat_queue(&res->lr_granted, lock, work_list);
+ rc += ldlm_plain_compat_queue(&res->lr_waiting, lock, work_list);
+
+ if (rc == 2) {
+ ldlm_resource_unlink_lock(lock);
+ ldlm_grant_lock(lock, grant_work);
+ }
+
+ RETURN(LDLM_ITER_CONTINUE);
}
+#endif /* HAVE_SERVER_SUPPORT */
-void ldlm_plain_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
- ldlm_policy_data_t *lpolicy)
+void ldlm_plain_policy_wire_to_local(const union ldlm_wire_policy_data *wpolicy,
+ union ldlm_policy_data *lpolicy)
{
- /* No policy for plain locks */
+ /* No policy for plain locks */
}
-void ldlm_plain_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
- ldlm_wire_policy_data_t *wpolicy)
+void ldlm_plain_policy_local_to_wire(const union ldlm_policy_data *lpolicy,
+ union ldlm_wire_policy_data *wpolicy)
{
- /* No policy for plain locks */
+ /* No policy for plain locks */
}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff