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 /*
  36  * This file is part of Lustre, http://www.lustre.org/
  37  * Lustre is a trademark of Sun Microsystems, Inc.
  38  *
  39  * lustre/ldlm/ldlm_inodebits.c
  40  *
  41  * Author: Peter Braam <braam@clusterfs.com>
  42  * Author: Phil Schwan <phil@clusterfs.com>
  43  */
  44
  45 #define DEBUG_SUBSYSTEM S_LDLM
  46 #ifndef __KERNEL__
  47 # include <liblustre.h>
  48 #endif
  49
  50 #include <lustre_dlm.h>
  51 #include <obd_support.h>
  52 #include <lustre_lib.h>
  53
  54 #include "ldlm_internal.h"
  55
  56 /* Determine if the lock is compatible with all locks on the queue. */
  57 static int
  58 ldlm_inodebits_compat_queue(cfs_list_t *queue, struct ldlm_lock *req,
  59                             cfs_list_t *work_list)
  60 {
  61         cfs_list_t *tmp;
  62         struct ldlm_lock *lock;
  63         ldlm_mode_t req_mode = req->l_req_mode;
  64         __u64 req_bits = req->l_policy_data.l_inodebits.bits;
  65         int compat = 1;
  66         ENTRY;
  67
  68         LASSERT(req_bits); /* There is no sense in lock with no bits set,
  69                               I think. Also such a lock would be compatible
  70                                with any other bit lock */
  71
  72         cfs_list_for_each(tmp, queue) {
  73                 cfs_list_t *mode_tail;
  74
  75                 lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
  76
  77                 if (req == lock)
  78                         RETURN(compat);
  79
  80                 /* last lock in mode group */
  81                 LASSERT(lock->l_sl_mode.prev != NULL);
  82                 mode_tail = &cfs_list_entry(lock->l_sl_mode.prev,
  83                                             struct ldlm_lock,
  84                                             l_sl_mode)->l_res_link;
  85
  86                 /* locks are compatible, bits don't matter */
  87                 if (lockmode_compat(lock->l_req_mode, req_mode)) {
  88                         /* jump to last lock in mode group */
  89                         tmp = mode_tail;
  90                         continue;
  91                 }
  92
  93                 for (;;) {
  94                         cfs_list_t *head;
  95
  96                         /* last lock in policy group */
  97                         tmp = &cfs_list_entry(lock->l_sl_policy.prev,
  98                                               struct ldlm_lock,
  99                                               l_sl_policy)->l_res_link;
 100
 101                         /* locks with bits overlapped are conflicting locks */
 102                         if (lock->l_policy_data.l_inodebits.bits & req_bits) {
 103                                 /* COS lock from the same client is
 104                                    not conflicting */
 105                                 if (lock->l_req_mode == LCK_COS &&
 106                                     lock->l_client_cookie == req->l_client_cookie)
 107                                         goto not_conflicting;
 108                                 /* conflicting policy */
 109                                 if (!work_list)
 110                                         RETURN(0);
 111
 112                                 compat = 0;
 113
 114                                 /* add locks of the policy group to
 115                                  * @work_list as blocking locks for
 116                                  * @req */
 117                                 if (lock->l_blocking_ast)
 118                                         ldlm_add_ast_work_item(lock, req,
 119                                                                work_list);
 120                                 head = &lock->l_sl_policy;
 121                                 cfs_list_for_each_entry(lock, head, l_sl_policy)
 122                                         if (lock->l_blocking_ast)
 123                                                 ldlm_add_ast_work_item(lock, req,
 124                                                                        work_list);
 125                         }
 126                 not_conflicting:
 127                         if (tmp == mode_tail)
 128                                 break;
 129
 130                         tmp = tmp->next;
 131                         lock = cfs_list_entry(tmp, struct ldlm_lock,
 132                                               l_res_link);
 133                 } /* loop over policy groups within one mode group */
 134         } /* loop over mode groups within @queue */
 135
 136         RETURN(compat);
 137 }
 138
 139 /* If first_enq is 0 (ie, called from ldlm_reprocess_queue):
 140   *   - blocking ASTs have already been sent
 141   *   - must call this function with the ns lock held
 142   *
 143   * If first_enq is 1 (ie, called from ldlm_lock_enqueue):
 144   *   - blocking ASTs have not been sent
 145   *   - must call this function with the ns lock held once */
 146 int ldlm_process_inodebits_lock(struct ldlm_lock *lock, int *flags,
 147                                 int first_enq, ldlm_error_t *err,
 148                                 cfs_list_t *work_list)
 149 {
 150         struct ldlm_resource *res = lock->l_resource;
 151         CFS_LIST_HEAD(rpc_list);
 152         int rc;
 153         ENTRY;
 154
 155         LASSERT(cfs_list_empty(&res->lr_converting));
 156         check_res_locked(res);
 157
 158         if (!first_enq) {
 159                 LASSERT(work_list != NULL);
 160                 rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, NULL);
 161                 if (!rc)
 162                         RETURN(LDLM_ITER_STOP);
 163                 rc = ldlm_inodebits_compat_queue(&res->lr_waiting, lock, NULL);
 164                 if (!rc)
 165                         RETURN(LDLM_ITER_STOP);
 166
 167                 ldlm_resource_unlink_lock(lock);
 168                 ldlm_grant_lock(lock, work_list);
 169                 RETURN(LDLM_ITER_CONTINUE);
 170         }
 171
 172  restart:
 173         rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, &rpc_list);
 174         rc += ldlm_inodebits_compat_queue(&res->lr_waiting, lock, &rpc_list);
 175
 176         if (rc != 2) {
 177                 /* If either of the compat_queue()s returned 0, then we
 178                  * have ASTs to send and must go onto the waiting list.
 179                  *
 180                  * bug 2322: we used to unlink and re-add here, which was a
 181                  * terrible folly -- if we goto restart, we could get
 182                  * re-ordered!  Causes deadlock, because ASTs aren't sent! */
 183                 if (cfs_list_empty(&lock->l_res_link))
 184                         ldlm_resource_add_lock(res, &res->lr_waiting, lock);
 185                 unlock_res(res);
 186                 rc = ldlm_run_ast_work(ldlm_res_to_ns(res), &rpc_list,
 187                                        LDLM_WORK_BL_AST);
 188                 lock_res(res);
 189                 if (rc == -ERESTART)
 190                         GOTO(restart, -ERESTART);
 191                 *flags |= LDLM_FL_BLOCK_GRANTED;
 192         } else {
 193                 ldlm_resource_unlink_lock(lock);
 194                 ldlm_grant_lock(lock, NULL);
 195         }
 196         RETURN(0);
 197 }
 198
 199 void ldlm_ibits_policy_wire_to_local(const ldlm_wire_policy_data_t *wpolicy,
 200                                      ldlm_policy_data_t *lpolicy)
 201 {
 202         memset(lpolicy, 0, sizeof(*lpolicy));
 203         lpolicy->l_inodebits.bits = wpolicy->l_inodebits.bits;
 204 }
 205
 206 void ldlm_ibits_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
 207                                      ldlm_wire_policy_data_t *wpolicy)
 208 {
 209         memset(wpolicy, 0, sizeof(*wpolicy));
 210         wpolicy->l_inodebits.bits = lpolicy->l_inodebits.bits;
 211 }