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 int 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         int rv = 0;
  38
  39         e = kmalloc(sizeof(struct rq_entry) + length, GFP_KERNEL);
  40         if (!e) {
  41                 log_print("dlm_add_requestqueue: out of memory\n");
  42                 return 0;
  43         }
  44
  45         e->nodeid = nodeid;
  46         memcpy(e->request, hd, length);
  47
  48         /* We need to check dlm_locking_stopped() after taking the mutex to
  49            avoid a race where dlm_recoverd enables locking and runs
  50            process_requestqueue between our earlier dlm_locking_stopped check
  51            and this addition to the requestqueue. */
  52
  53         mutex_lock(&ls->ls_requestqueue_mutex);
  54         if (dlm_locking_stopped(ls))
  55                 list_add_tail(&e->list, &ls->ls_requestqueue);
  56         else {
  57                 log_debug(ls, "dlm_add_requestqueue skip from %d", nodeid);
  58                 kfree(e);
  59                 rv = -EAGAIN;
  60         }
  61         mutex_unlock(&ls->ls_requestqueue_mutex);
  62         return rv;
  63 }
  64
  65 int dlm_process_requestqueue(struct dlm_ls *ls)
  66 {
  67         struct rq_entry *e;
  68         struct dlm_header *hd;
  69         int error = 0;
  70
  71         mutex_lock(&ls->ls_requestqueue_mutex);
  72
  73         for (;;) {
  74                 if (list_empty(&ls->ls_requestqueue)) {
  75                         mutex_unlock(&ls->ls_requestqueue_mutex);
  76                         error = 0;
  77                         break;
  78                 }
  79                 e = list_entry(ls->ls_requestqueue.next, struct rq_entry, list);
  80                 mutex_unlock(&ls->ls_requestqueue_mutex);
  81
  82                 hd = (struct dlm_header *) e->request;
  83                 error = dlm_receive_message(hd, e->nodeid, 1);
  84
  85                 if (error == -EINTR) {
  86                         /* entry is left on requestqueue */
  87                         log_debug(ls, "process_requestqueue abort eintr");
  88                         break;
  89                 }
  90
  91                 mutex_lock(&ls->ls_requestqueue_mutex);
  92                 list_del(&e->list);
  93                 kfree(e);
  94
  95                 if (dlm_locking_stopped(ls)) {
  96                         log_debug(ls, "process_requestqueue abort running");
  97                         mutex_unlock(&ls->ls_requestqueue_mutex);
  98                         error = -EINTR;
  99                         break;
 100                 }
 101                 schedule();
 102         }
 103
 104         return error;
 105 }
 106
 107 /*
 108  * After recovery is done, locking is resumed and dlm_recoverd takes all the
 109  * saved requests and processes them as they would have been by dlm_recvd.  At
 110  * the same time, dlm_recvd will start receiving new requests from remote
 111  * nodes.  We want to delay dlm_recvd processing new requests until
 112  * dlm_recoverd has finished processing the old saved requests.
 113  */
 114
 115 void dlm_wait_requestqueue(struct dlm_ls *ls)
 116 {
 117         for (;;) {
 118                 mutex_lock(&ls->ls_requestqueue_mutex);
 119                 if (list_empty(&ls->ls_requestqueue))
 120                         break;
 121                 if (dlm_locking_stopped(ls))
 122                         break;
 123                 mutex_unlock(&ls->ls_requestqueue_mutex);
 124                 schedule();
 125         }
 126         mutex_unlock(&ls->ls_requestqueue_mutex);
 127 }
 128
 129 static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid)
 130 {
 131         uint32_t type = ms->m_type;
 132
 133         /* the ls is being cleaned up and freed by release_lockspace */
 134         if (!ls->ls_count)
 135                 return 1;
 136
 137         if (dlm_is_removed(ls, nodeid))
 138                 return 1;
 139
 140         /* directory operations are always purged because the directory is
 141            always rebuilt during recovery and the lookups resent */
 142
 143         if (type == DLM_MSG_REMOVE ||
 144             type == DLM_MSG_LOOKUP ||
 145             type == DLM_MSG_LOOKUP_REPLY)
 146                 return 1;
 147
 148         if (!dlm_no_directory(ls))
 149                 return 0;
 150
 151         /* with no directory, the master is likely to change as a part of
 152            recovery; requests to/from the defunct master need to be purged */
 153
 154         switch (type) {
 155         case DLM_MSG_REQUEST:
 156         case DLM_MSG_CONVERT:
 157         case DLM_MSG_UNLOCK:
 158         case DLM_MSG_CANCEL:
 159                 /* we're no longer the master of this resource, the sender
 160                    will resend to the new master (see waiter_needs_recovery) */
 161
 162                 if (dlm_hash2nodeid(ls, ms->m_hash) != dlm_our_nodeid())
 163                         return 1;
 164                 break;
 165
 166         case DLM_MSG_REQUEST_REPLY:
 167         case DLM_MSG_CONVERT_REPLY:
 168         case DLM_MSG_UNLOCK_REPLY:
 169         case DLM_MSG_CANCEL_REPLY:
 170         case DLM_MSG_GRANT:
 171                 /* this reply is from the former master of the resource,
 172                    we'll resend to the new master if needed */
 173
 174                 if (dlm_hash2nodeid(ls, ms->m_hash) != nodeid)
 175                         return 1;
 176                 break;
 177         }
 178
 179         return 0;
 180 }
 181
 182 void dlm_purge_requestqueue(struct dlm_ls *ls)
 183 {
 184         struct dlm_message *ms;
 185         struct rq_entry *e, *safe;
 186
 187         mutex_lock(&ls->ls_requestqueue_mutex);
 188         list_for_each_entry_safe(e, safe, &ls->ls_requestqueue, list) {
 189                 ms = (struct dlm_message *) e->request;
 190
 191                 if (purge_request(ls, ms, e->nodeid)) {
 192                         list_del(&e->list);
 193                         kfree(e);
 194                 }
 195         }
 196         mutex_unlock(&ls->ls_requestqueue_mutex);
 197 }
 198