fs/dlm/requestqueue.c

   1 /******************************************************************************
   2 *******************************************************************************
   3 **
   4 **  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
   5 **
   6 **  This copyrighted material is made available to anyone wishing to use,
   7 **  modify, copy, or redistribute it subject to the terms and conditions
   8 **  of the GNU General Public License v.2.
   9 **
  10 *******************************************************************************
  11 ******************************************************************************/
  12
  13 #include "dlm_internal.h"
  14 #include "member.h"
  15 #include "lock.h"
  16 #include "dir.h"
  17 #include "config.h"
  18 #include "requestqueue.h"
  19
  20 struct rq_entry {
  21         struct list_head list;
  22         int nodeid;
  23         char request[1];
  24 };
  25
  26 /*
  27  * Requests received while the lockspace is in recovery get added to the
  28  * request queue and processed when recovery is complete.  This happens when
  29  * the lockspace is suspended on some nodes before it is on others, or the
  30  * lockspace is enabled on some while still suspended on others.
  31  */
  32
  33 void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_header *hd)
  34 {
  35         struct rq_entry *e;
  36         int length = hd->h_length;
  37
  38         if (dlm_is_removed(ls, nodeid))
  39                 return;
  40
  41         e = kmalloc(sizeof(struct rq_entry) + length, GFP_KERNEL);
  42         if (!e) {
  43                 log_print("dlm_add_requestqueue: out of memory\n");
  44                 return;
  45         }
  46
  47         e->nodeid = nodeid;
  48         memcpy(e->request, hd, length);
  49
  50         mutex_lock(&ls->ls_requestqueue_mutex);
  51         list_add_tail(&e->list, &ls->ls_requestqueue);
  52         mutex_unlock(&ls->ls_requestqueue_mutex);
  53 }
  54
  55 int dlm_process_requestqueue(struct dlm_ls *ls)
  56 {
  57         struct rq_entry *e;
  58         struct dlm_header *hd;
  59         int error = 0;
  60
  61         mutex_lock(&ls->ls_requestqueue_mutex);
  62
  63         for (;;) {
  64                 if (list_empty(&ls->ls_requestqueue)) {
  65                         mutex_unlock(&ls->ls_requestqueue_mutex);
  66                         error = 0;
  67                         break;
  68                 }
  69                 e = list_entry(ls->ls_requestqueue.next, struct rq_entry, list);
  70                 mutex_unlock(&ls->ls_requestqueue_mutex);
  71
  72                 hd = (struct dlm_header *) e->request;
  73                 error = dlm_receive_message(hd, e->nodeid, 1);
  74
  75                 if (error == -EINTR) {
  76                         /* entry is left on requestqueue */
  77                         log_debug(ls, "process_requestqueue abort eintr");
  78                         break;
  79                 }
  80
  81                 mutex_lock(&ls->ls_requestqueue_mutex);
  82                 list_del(&e->list);
  83                 kfree(e);
  84
  85                 if (dlm_locking_stopped(ls)) {
  86                         log_debug(ls, "process_requestqueue abort running");
  87                         mutex_unlock(&ls->ls_requestqueue_mutex);
  88                         error = -EINTR;
  89                         break;
  90                 }
  91                 schedule();
  92         }
  93
  94         return error;
  95 }
  96
  97 /*
  98  * After recovery is done, locking is resumed and dlm_recoverd takes all the
  99  * saved requests and processes them as they would have been by dlm_recvd.  At
 100  * the same time, dlm_recvd will start receiving new requests from remote
 101  * nodes.  We want to delay dlm_recvd processing new requests until
 102  * dlm_recoverd has finished processing the old saved requests.
 103  */
 104
 105 void dlm_wait_requestqueue(struct dlm_ls *ls)
 106 {
 107         for (;;) {
 108                 mutex_lock(&ls->ls_requestqueue_mutex);
 109                 if (list_empty(&ls->ls_requestqueue))
 110                         break;
 111                 if (dlm_locking_stopped(ls))
 112                         break;
 113                 mutex_unlock(&ls->ls_requestqueue_mutex);
 114                 schedule();
 115         }
 116         mutex_unlock(&ls->ls_requestqueue_mutex);
 117 }
 118
 119 static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid)
 120 {
 121         uint32_t type = ms->m_type;
 122
 123         if (dlm_is_removed(ls, nodeid))
 124                 return 1;
 125
 126         /* directory operations are always purged because the directory is
 127            always rebuilt during recovery and the lookups resent */
 128
 129         if (type == DLM_MSG_REMOVE ||
 130             type == DLM_MSG_LOOKUP ||
 131             type == DLM_MSG_LOOKUP_REPLY)
 132                 return 1;
 133
 134         if (!dlm_no_directory(ls))
 135                 return 0;
 136
 137         /* with no directory, the master is likely to change as a part of
 138            recovery; requests to/from the defunct master need to be purged */
 139
 140         switch (type) {
 141         case DLM_MSG_REQUEST:
 142         case DLM_MSG_CONVERT:
 143         case DLM_MSG_UNLOCK:
 144         case DLM_MSG_CANCEL:
 145                 /* we're no longer the master of this resource, the sender
 146                    will resend to the new master (see waiter_needs_recovery) */
 147
 148                 if (dlm_hash2nodeid(ls, ms->m_hash) != dlm_our_nodeid())
 149                         return 1;
 150                 break;
 151
 152         case DLM_MSG_REQUEST_REPLY:
 153         case DLM_MSG_CONVERT_REPLY:
 154         case DLM_MSG_UNLOCK_REPLY:
 155         case DLM_MSG_CANCEL_REPLY:
 156         case DLM_MSG_GRANT:
 157                 /* this reply is from the former master of the resource,
 158                    we'll resend to the new master if needed */
 159
 160                 if (dlm_hash2nodeid(ls, ms->m_hash) != nodeid)
 161                         return 1;
 162                 break;
 163         }
 164
 165         return 0;
 166 }
 167
 168 void dlm_purge_requestqueue(struct dlm_ls *ls)
 169 {
 170         struct dlm_message *ms;
 171         struct rq_entry *e, *safe;
 172
 173         mutex_lock(&ls->ls_requestqueue_mutex);
 174         list_for_each_entry_safe(e, safe, &ls->ls_requestqueue, list) {
 175                 ms = (struct dlm_message *) e->request;
 176
 177                 if (purge_request(ls, ms, e->nodeid)) {
 178                         list_del(&e->list);
 179                         kfree(e);
 180                 }
 181         }
 182         mutex_unlock(&ls->ls_requestqueue_mutex);
 183 }
 184