/* * GPL HEADER START * * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * 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. * * 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). * * 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. * * GPL HEADER END */ /* * Copyright (c) 2004, 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_inodebits.c * * Author: Peter Braam * Author: Phil Schwan */ /** * This file contains implementation of IBITS lock type * * IBITS lock type contains a bit mask determining various properties of an * object. The meanings of specific bits are specific to the caller and are * opaque to LDLM code. * * Locks with intersecting bitmasks and conflicting lock modes (e.g. LCK_PW) * are considered conflicting. See the lock mode compatibility matrix * in lustre_dlm.h. */ #define DEBUG_SUBSYSTEM S_LDLM #ifndef __KERNEL__ # include #endif #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 * * IBITS locks in granted queue are organized in bunches of * same-mode/same-bits locks called "skip lists". The First lock in the * bunch contains a pointer to the end of the bunch. This allows us to * skip an entire bunch when iterating the list in search for conflicting * locks if first lock of the bunch is not conflicting with us. */ static int ldlm_inodebits_compat_queue(cfs_list_t *queue, struct ldlm_lock *req, cfs_list_t *work_list) { cfs_list_t *tmp; struct ldlm_lock *lock; ldlm_mode_t req_mode = req->l_req_mode; __u64 req_bits = req->l_policy_data.l_inodebits.bits; int compat = 1; ENTRY; LASSERT(req_bits); /* There is no sense in lock with no bits set, I think. Also such a lock would be compatible with any other bit lock */ cfs_list_for_each(tmp, queue) { cfs_list_t *mode_tail; 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); /* last lock in mode group */ LASSERT(lock->l_sl_mode.prev != NULL); mode_tail = &cfs_list_entry(lock->l_sl_mode.prev, struct ldlm_lock, l_sl_mode)->l_res_link; /* locks are compatible, bits don't matter */ if (lockmode_compat(lock->l_req_mode, req_mode)) { /* jump to last lock in mode group */ tmp = mode_tail; continue; } for (;;) { cfs_list_t *head; /* Advance loop cursor to last lock in policy group. */ tmp = &cfs_list_entry(lock->l_sl_policy.prev, struct ldlm_lock, l_sl_policy)->l_res_link; /* Locks with overlapping bits conflict. */ if (lock->l_policy_data.l_inodebits.bits & req_bits) { /* COS lock mode has a special compatibility * requirement: it is only compatible with * locks from the same client. */ if (lock->l_req_mode == LCK_COS && lock->l_client_cookie == req->l_client_cookie) goto not_conflicting; /* Found a conflicting policy group. */ if (!work_list) RETURN(0); compat = 0; /* Add locks of the policy group to @work_list * as blocking locks for @req */ if (lock->l_blocking_ast) ldlm_add_ast_work_item(lock, req, work_list); head = &lock->l_sl_policy; cfs_list_for_each_entry(lock, head, l_sl_policy) if (lock->l_blocking_ast) ldlm_add_ast_work_item(lock, req, work_list); } not_conflicting: if (tmp == mode_tail) break; tmp = tmp->next; lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link); } /* Loop over policy groups within one mode group. */ } /* Loop over mode groups within @queue. */ RETURN(compat); } /** * Process a granting attempt for IBITS 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_inodebits_lock(struct ldlm_lock *lock, __u64 *flags, int first_enq, ldlm_error_t *err, cfs_list_t *work_list) { struct ldlm_resource *res = lock->l_resource; CFS_LIST_HEAD(rpc_list); int rc; ENTRY; LASSERT(cfs_list_empty(&res->lr_converting)); check_res_locked(res); /* (*flags & LDLM_FL_BLOCK_NOWAIT) is for layout lock right now. */ if (!first_enq || (*flags & LDLM_FL_BLOCK_NOWAIT)) { *err = ELDLM_LOCK_ABORTED; if (*flags & LDLM_FL_BLOCK_NOWAIT) *err = ELDLM_LOCK_WOULDBLOCK; rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, NULL); if (!rc) RETURN(LDLM_ITER_STOP); rc = ldlm_inodebits_compat_queue(&res->lr_waiting, lock, NULL); if (!rc) RETURN(LDLM_ITER_STOP); ldlm_resource_unlink_lock(lock); ldlm_grant_lock(lock, work_list); *err = ELDLM_OK; RETURN(LDLM_ITER_CONTINUE); } restart: rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, &rpc_list); rc += ldlm_inodebits_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, rc); *flags |= LDLM_FL_BLOCK_GRANTED; } else { ldlm_resource_unlink_lock(lock); ldlm_grant_lock(lock, NULL); } RETURN(0); } #endif /* HAVE_SERVER_SUPPORT */ void ldlm_ibits_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy, ldlm_policy_data_t *lpolicy) { memset(lpolicy, 0, sizeof(*lpolicy)); lpolicy->l_inodebits.bits = wpolicy->l_inodebits.bits; } void ldlm_ibits_policy_local_to_wire(const ldlm_policy_data_t *lpolicy, ldlm_wire_policy_data_t *wpolicy) { memset(wpolicy, 0, sizeof(*wpolicy)); wpolicy->l_inodebits.bits = lpolicy->l_inodebits.bits; }