fs/dlm/requestqueue.c

   1 /******************************************************************************
   2 *******************************************************************************
   3 **
   4 **  Copyright (C) 2005-2007 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[0];
  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         e = kmalloc(sizeof(struct rq_entry) + length, GFP_KERNEL);
  39         if (!e) {
  40                 log_print("dlm_add_requestqueue: out of memory len %d", length);
  41                 return;
  42         }
  43
  44         e->nodeid = nodeid;
  45         memcpy(e->request, hd, length);
  46
  47         mutex_lock(&ls->ls_requestqueue_mutex);
  48         list_add_tail(&e->list, &ls->ls_requestqueue);
  49         mutex_unlock(&ls->ls_requestqueue_mutex);
  50 }
  51
  52 /*
  53  * Called by dlm_recoverd to process normal messages saved while recovery was
  54  * happening.  Normal locking has been enabled before this is called.  dlm_recv
  55  * upon receiving a message, will wait for all saved messages to be drained
  56  * here before processing the message it got.  If a new dlm_ls_stop() arrives
  57  * while we're processing these saved messages, it may block trying to suspend
  58  * dlm_recv if dlm_recv is waiting for us in dlm_wait_requestqueue.  In that
  59  * case, we don't abort since locking_stopped is still 0.  If dlm_recv is not
  60  * waiting for us, then this processing may be aborted due to locking_stopped.
  61  */
  62
  63 int dlm_process_requestqueue(struct dlm_ls *ls)
  64 {
  65         struct rq_entry *e;
  66         int error = 0;
  67
  68         mutex_lock(&ls->ls_requestqueue_mutex);
  69
  70         for (;;) {
  71                 if (list_empty(&ls->ls_requestqueue)) {
  72                         mutex_unlock(&ls->ls_requestqueue_mutex);
  73                         error = 0;
  74                         break;
  75                 }
  76                 e = list_entry(ls->ls_requestqueue.next, struct rq_entry, list);
  77                 mutex_unlock(&ls->ls_requestqueue_mutex);
  78
  79                 dlm_receive_message_saved(ls, (struct dlm_message *)e->request);
  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_recv.  At
 100  * the same time, dlm_recv will start receiving new requests from remote nodes.
 101  * We want to delay dlm_recv processing new requests until dlm_recoverd has
 102  * finished processing the old saved requests.  We don't check for locking
 103  * stopped here because dlm_ls_stop won't stop locking until it's suspended us
 104  * (dlm_recv).
 105  */
 106
 107 void dlm_wait_requestqueue(struct dlm_ls *ls)
 108 {
 109         for (;;) {
 110                 mutex_lock(&ls->ls_requestqueue_mutex);
 111                 if (list_empty(&ls->ls_requestqueue))
 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         /* the ls is being cleaned up and freed by release_lockspace */
 124         if (!ls->ls_count)
 125                 return 1;
 126
 127         if (dlm_is_removed(ls, nodeid))
 128                 return 1;
 129
 130         /* directory operations are always purged because the directory is
 131            always rebuilt during recovery and the lookups resent */
 132
 133         if (type == DLM_MSG_REMOVE ||
 134             type == DLM_MSG_LOOKUP ||
 135             type == DLM_MSG_LOOKUP_REPLY)
 136                 return 1;
 137
 138         if (!dlm_no_directory(ls))
 139                 return 0;
 140
 141         /* with no directory, the master is likely to change as a part of
 142            recovery; requests to/from the defunct master need to be purged */
 143
 144         switch (type) {
 145         case DLM_MSG_REQUEST:
 146         case DLM_MSG_CONVERT:
 147         case DLM_MSG_UNLOCK:
 148         case DLM_MSG_CANCEL:
 149                 /* we're no longer the master of this resource, the sender
 150                    will resend to the new master (see waiter_needs_recovery) */
 151
 152                 if (dlm_hash2nodeid(ls, ms->m_hash) != dlm_our_nodeid())
 153                         return 1;
 154                 break;
 155
 156         case DLM_MSG_REQUEST_REPLY:
 157         case DLM_MSG_CONVERT_REPLY:
 158         case DLM_MSG_UNLOCK_REPLY:
 159         case DLM_MSG_CANCEL_REPLY:
 160         case DLM_MSG_GRANT:
 161                 /* this reply is from the former master of the resource,
 162                    we'll resend to the new master if needed */
 163
 164                 if (dlm_hash2nodeid(ls, ms->m_hash) != nodeid)
 165                         return 1;
 166                 break;
 167         }
 168
 169         return 0;
 170 }
 171
 172 void dlm_purge_requestqueue(struct dlm_ls *ls)
 173 {
 174         struct dlm_message *ms;
 175         struct rq_entry *e, *safe;
 176
 177         mutex_lock(&ls->ls_requestqueue_mutex);
 178         list_for_each_entry_safe(e, safe, &ls->ls_requestqueue, list) {
 179                 ms = (struct dlm_message *) e->request;
 180
 181                 if (purge_request(ls, ms, e->nodeid)) {
 182                         list_del(&e->list);
 183                         kfree(e);
 184                 }
 185         }
 186         mutex_unlock(&ls->ls_requestqueue_mutex);
 187 }
 188