X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Fldlm%2Fldlm_plain.c;h=bbc355f5d5d6aa596e9b9b0bbf1594f80add9524;hp=fc6f0291ca2a5463c34233a135e9ff5e11675e5e;hb=5546521fa5d619865902c867d2170dbf1a51c778;hpb=4dad795bcc8f4d99e25563b056cf950b613c2c17 diff --git a/lustre/ldlm/ldlm_plain.c b/lustre/ldlm/ldlm_plain.c index fc6f029..bbc355f 100644 --- a/lustre/ldlm/ldlm_plain.c +++ b/lustre/ldlm/ldlm_plain.c @@ -1,142 +1,204 @@ -/* -*- 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 - * Author: Phil Schwan + * 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, 2013, 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 + * Author: Phil Schwan + */ + +/** + * 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 -#include -#include -#else -#include -#endif - -static int -ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *new, - int send_cbs, int first_enq) +#include +#include +#include + +#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 *tmp, *pos; - ldlm_mode_t mode = new->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; - 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; + list_for_each_entry_safe(lock, next_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); - 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. */ + 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)) 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); + + { + struct list_head *head; + + head = &lock->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); } -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, enum ldlm_error *err, + struct list_head *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; - 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); - } + struct ldlm_resource *res = lock->l_resource; + struct list_head rpc_list; + int rc; + ENTRY; + + 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); + 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 (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, rc); *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 union ldlm_wire_policy_data *wpolicy, + union ldlm_policy_data *lpolicy) +{ + /* No policy for plain locks */ +} - RETURN(LDLM_ITER_CONTINUE); +void ldlm_plain_policy_local_to_wire(const union ldlm_policy_data *lpolicy, + union ldlm_wire_policy_data *wpolicy) +{ + /* No policy for plain locks */ }