lustre/ldlm/ldlm_inodebits.c

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