lustre/ldlm/ldlm_inodebits.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * GPL HEADER START
   5  *
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License version 2 for more details (a copy is included
  16  * in the LICENSE file that accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * version 2 along with this program; If not, see
  20  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  21  *
  22  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  23  * CA 95054 USA or visit www.sun.com if you need additional information or
  24  * have any questions.
  25  *
  26  * GPL HEADER END
  27  */
  28 /*
  29  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
  30  * Use is subject to license terms.
  31  *
  32  * Copyright (c) 2011, Whamcloud, Inc.
  33  */
  34 /*
  35  * This file is part of Lustre, http://www.lustre.org/
  36  * Lustre is a trademark of Sun Microsystems, Inc.
  37  *
  38  * lustre/ldlm/ldlm_inodebits.c
  39  *
  40  * Author: Peter Braam <braam@clusterfs.com>
  41  * Author: Phil Schwan <phil@clusterfs.com>
  42  */
  43
  44 #define DEBUG_SUBSYSTEM S_LDLM
  45 #ifndef __KERNEL__
  46 # include <liblustre.h>
  47 #endif
  48
  49 #include <lustre_dlm.h>
  50 #include <obd_support.h>
  51 #include <lustre_lib.h>
  52
  53 #include "ldlm_internal.h"
  54
  55 /* Determine if the lock is compatible with all locks on the queue. */
  56 static int
  57 ldlm_inodebits_compat_queue(cfs_list_t *queue, struct ldlm_lock *req,
  58                             cfs_list_t *work_list)
  59 {
  60         cfs_list_t *tmp;
  61         struct ldlm_lock *lock;
  62         ldlm_mode_t req_mode = req->l_req_mode;
  63         __u64 req_bits = req->l_policy_data.l_inodebits.bits;
  64         int compat = 1;
  65         ENTRY;
  66
  67         LASSERT(req_bits); /* There is no sense in lock with no bits set,
  68                               I think. Also such a lock would be compatible
  69                                with any other bit lock */
  70
  71         cfs_list_for_each(tmp, queue) {
  72                 cfs_list_t *mode_tail;
  73
  74                 lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
  75
  76                 if (req == lock)
  77                         RETURN(compat);
  78
  79                 /* last lock in mode group */
  80                 LASSERT(lock->l_sl_mode.prev != NULL);
  81                 mode_tail = &cfs_list_entry(lock->l_sl_mode.prev,
  82                                             struct ldlm_lock,
  83                                             l_sl_mode)->l_res_link;
  84
  85                 /* locks are compatible, bits don't matter */
  86                 if (lockmode_compat(lock->l_req_mode, req_mode)) {
  87                         /* jump to last lock in mode group */
  88                         tmp = mode_tail;
  89                         continue;
  90                 }
  91
  92                 for (;;) {
  93                         cfs_list_t *head;
  94
  95                         /* last lock in policy group */
  96                         tmp = &cfs_list_entry(lock->l_sl_policy.prev,
  97                                               struct ldlm_lock,
  98                                               l_sl_policy)->l_res_link;
  99
 100                         /* locks with bits overlapped are conflicting locks */
 101                         if (lock->l_policy_data.l_inodebits.bits & req_bits) {
 102                                 /* COS lock from the same client is
 103                                    not conflicting */
 104                                 if (lock->l_req_mode == LCK_COS &&
 105                                     lock->l_client_cookie == req->l_client_cookie)
 106                                         goto not_conflicting;
 107                                 /* conflicting policy */
 108                                 if (!work_list)
 109                                         RETURN(0);
 110
 111                                 compat = 0;
 112
 113                                 /* add locks of the policy group to
 114                                  * @work_list as blocking locks for
 115                                  * @req */
 116                                 if (lock->l_blocking_ast)
 117                                         ldlm_add_ast_work_item(lock, req,
 118                                                                work_list);
 119                                 head = &lock->l_sl_policy;
 120                                 cfs_list_for_each_entry(lock, head, l_sl_policy)
 121                                         if (lock->l_blocking_ast)
 122                                                 ldlm_add_ast_work_item(lock, req,
 123                                                                        work_list);
 124                         }
 125                 not_conflicting:
 126                         if (tmp == mode_tail)
 127                                 break;
 128
 129                         tmp = tmp->next;
 130                         lock = cfs_list_entry(tmp, struct ldlm_lock,
 131                                               l_res_link);
 132                 } /* loop over policy groups within one mode group */
 133         } /* loop over mode groups within @queue */
 134
 135         RETURN(compat);
 136 }
 137
 138 /* If first_enq is 0 (ie, called from ldlm_reprocess_queue):
 139   *   - blocking ASTs have already been sent
 140   *   - must call this function with the ns lock held
 141   *
 142   * If first_enq is 1 (ie, called from ldlm_lock_enqueue):
 143   *   - blocking ASTs have not been sent
 144   *   - must call this function with the ns lock held once */
 145 int ldlm_process_inodebits_lock(struct ldlm_lock *lock, int *flags,
 146                                 int first_enq, ldlm_error_t *err,
 147                                 cfs_list_t *work_list)
 148 {
 149         struct ldlm_resource *res = lock->l_resource;
 150         CFS_LIST_HEAD(rpc_list);
 151         int rc;
 152         ENTRY;
 153
 154         LASSERT(cfs_list_empty(&res->lr_converting));
 155         check_res_locked(res);
 156
 157         if (!first_enq) {
 158                 LASSERT(work_list != NULL);
 159                 rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, NULL);
 160                 if (!rc)
 161                         RETURN(LDLM_ITER_STOP);
 162                 rc = ldlm_inodebits_compat_queue(&res->lr_waiting, lock, NULL);
 163                 if (!rc)
 164                         RETURN(LDLM_ITER_STOP);
 165
 166                 ldlm_resource_unlink_lock(lock);
 167                 ldlm_grant_lock(lock, work_list);
 168                 RETURN(LDLM_ITER_CONTINUE);
 169         }
 170
 171  restart:
 172         rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, &rpc_list);
 173         rc += ldlm_inodebits_compat_queue(&res->lr_waiting, lock, &rpc_list);
 174
 175         if (rc != 2) {
 176                 /* If either of the compat_queue()s returned 0, then we
 177                  * have ASTs to send and must go onto the waiting list.
 178                  *
 179                  * bug 2322: we used to unlink and re-add here, which was a
 180                  * terrible folly -- if we goto restart, we could get
 181                  * re-ordered!  Causes deadlock, because ASTs aren't sent! */
 182                 if (cfs_list_empty(&lock->l_res_link))
 183                         ldlm_resource_add_lock(res, &res->lr_waiting, lock);
 184                 unlock_res(res);
 185                 rc = ldlm_run_ast_work(ldlm_res_to_ns(res), &rpc_list,
 186                                        LDLM_WORK_BL_AST);
 187                 lock_res(res);
 188                 if (rc == -ERESTART)
 189                         GOTO(restart, -ERESTART);
 190                 *flags |= LDLM_FL_BLOCK_GRANTED;
 191         } else {
 192                 ldlm_resource_unlink_lock(lock);
 193                 ldlm_grant_lock(lock, NULL);
 194         }
 195         RETURN(0);
 196 }
 197
 198 void ldlm_ibits_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
 199                                      ldlm_policy_data_t *lpolicy)
 200 {
 201         memset(lpolicy, 0, sizeof(*lpolicy));
 202         lpolicy->l_inodebits.bits = wpolicy->l_inodebits.bits;
 203 }
 204
 205 void ldlm_ibits_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
 206                                      ldlm_wire_policy_data_t *wpolicy)
 207 {
 208         memset(wpolicy, 0, sizeof(*wpolicy));
 209         wpolicy->l_inodebits.bits = lpolicy->l_inodebits.bits;
 210 }