-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
+/*
+ * GPL HEADER START
*
- * Copyright (c) 2002, 2003 Cluster File Systems, Inc.
- * Author: Peter Braam <braam@clusterfs.com>
- * Author: Phil Schwan <phil@clusterfs.com>
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
- * This file is part of Lustre, http://www.lustre.org.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
*
- * Lustre is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
*
- * Lustre is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * 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
*
- * You should have received a copy of the GNU General Public License
- * along with Lustre; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * 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.
+ *
+ * GPL HEADER END
+ */
+/*
+ * 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/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ *
+ * lustre/ldlm/ldlm_plain.c
+ *
+ * Author: Peter Braam <braam@clusterfs.com>
+ * 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 <linux/lustre_dlm.h>
-#include <linux/obd_support.h>
-#include <linux/lustre_lib.h>
+#include <lustre_dlm.h>
+#include <obd_support.h>
+#include <lustre_lib.h>
#else
#include <liblustre.h>
#endif
-static int
-ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *new,
- int send_cbs, int first_enq)
+#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)
{
- struct list_head *tmp, *pos;
- ldlm_mode_t mode = new->l_req_mode;
+ cfs_list_t *tmp;
+ struct ldlm_lock *lock;
+ ldlm_mode_t req_mode = req->l_req_mode;
int compat = 1;
ENTRY;
- list_for_each_safe(tmp, pos, queue) {
- struct ldlm_lock *old;
+ lockmode_verify(req_mode);
- old = list_entry(tmp, struct ldlm_lock, l_res_link);
- if (old == new)
- continue;
+ cfs_list_for_each(tmp, queue) {
+ lock = cfs_list_entry(tmp, struct ldlm_lock, 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);
- if (lockmode_compat(old->l_req_mode, mode) &&
- lockmode_compat(old->l_granted_mode, mode)) {
- CDEBUG(D_OTHER, "lock modes are compatible, next.\n");
+ /* Advance loop cursor to last lock of mode group. */
+ tmp = &cfs_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)
+ RETURN(0);
compat = 0;
- /* if we're reprocessing the lock then the blocking ASTs
- * have already been sent. No need to continue. */
- if (!first_enq)
- break;
-
- if (send_cbs && (old->l_blocking_ast != NULL)) {
- CDEBUG(D_DLMTRACE, "lock %p incompatible; "
- "sending blocking AST.\n", old);
- ldlm_add_ast_work_item(old, new, NULL, 0);
- } else if (!(old->l_flags & LDLM_FL_LOCAL)) {
- CDEBUG(D_DLMTRACE, "lock %p incompatible; "
- "setting blocking AST.\n", old);
- old->l_flags |= LDLM_FL_AST_SENT;
- } else {
- CDEBUG(D_DLMTRACE, "local lock %p incompatible.\n",
- old);
+ /* 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;
+
+ head = &lock->l_sl_mode;
+ cfs_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);
}
-int
-ldlm_plain_enqueue(struct ldlm_lock **lockp, void *cookie, int *flags,
- int first_enq, ldlm_error_t *err)
+/**
+ * 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
+ *
+ * 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,
+ cfs_list_t *work_list)
{
- struct ldlm_lock *lock = *lockp;
struct ldlm_resource *res = lock->l_resource;
- int convert_compat = 1;
- int waiting_compat = 1;
- int granted_compat = 1;
+ CFS_LIST_HEAD(rpc_list);
+ int rc;
ENTRY;
- /* FIXME: We may want to optimize by checking lr_most_restr */
-
- /* On the first enqueue of this lock scan all of the queues
- * to set the LDLM_FL_AST_SENT flag in conflicting locks.
- * When the completion AST on the client side runs and sees
- * this flag is will set the LDLM_FL_CB_PENDING flag in the
- * lock so the client will know to cancel the lock as soon
- * as possible. This saves us from sending a blocking AST
- * in addition to the completion AST.
- *
- * If it's NOT the first enqueue of this lock then it must be
- * the first eligible lock in the queues because of the way that
- * ldlm_reprocess_all() works. So we don't have to check the
- * converting or waiting queues. */
- if (first_enq) {
- if (!list_empty(&res->lr_converting)) {
- convert_compat = 0;
- ldlm_plain_compat_queue(&res->lr_converting,
- lock, 0, first_enq);
- }
- if (!list_empty(&res->lr_waiting)) {
- waiting_compat = 0;
- ldlm_plain_compat_queue(&res->lr_waiting,
- lock, 0, first_enq);
- }
+ check_res_locked(res);
+ LASSERT(cfs_list_empty(&res->lr_converting));
+
+ if (!first_enq) {
+ LASSERT(work_list != NULL);
+ rc = ldlm_plain_compat_queue(&res->lr_granted, lock, NULL);
+ if (!rc)
+ RETURN(LDLM_ITER_STOP);
+ rc = ldlm_plain_compat_queue(&res->lr_waiting, lock, NULL);
+ if (!rc)
+ RETURN(LDLM_ITER_STOP);
+
+ ldlm_resource_unlink_lock(lock);
+ ldlm_grant_lock(lock, work_list);
+ RETURN(LDLM_ITER_CONTINUE);
}
- granted_compat =
- ldlm_plain_compat_queue(&res->lr_granted, lock, 1, first_enq);
- if (!convert_compat) {
- *flags |= LDLM_FL_BLOCK_CONV;
- RETURN(LDLM_ITER_STOP);
- }
- if (!waiting_compat) {
- *flags |= LDLM_FL_BLOCK_WAIT;
- RETURN(LDLM_ITER_STOP);
- }
- if (!granted_compat) {
+ 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;
- RETURN(LDLM_ITER_STOP);
+ } else {
+ ldlm_resource_unlink_lock(lock);
+ ldlm_grant_lock(lock, NULL);
}
+ RETURN(0);
+}
+#endif /* HAVE_SERVER_SUPPORT */
- list_del_init(&lock->l_res_link);
- ldlm_grant_lock(lock, NULL, 0);
-
- if (lock->l_flags & LDLM_FL_AST_SENT) {
- CDEBUG(D_DLMTRACE, "granted lock %p with AST set\n", lock);
- *flags |= (lock->l_flags & LDLM_FL_AST_SENT);
- }
+void ldlm_plain_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
+ ldlm_policy_data_t *lpolicy)
+{
+ /* No policy for plain locks */
+}
- RETURN(LDLM_ITER_CONTINUE);
+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