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         uint32_t recover_seq;
  23         int nodeid;
  24         struct dlm_message request;
  25 };
  26
  27 /*
  28  * Requests received while the lockspace is in recovery get added to the
  29  * request queue and processed when recovery is complete.  This happens when
  30  * the lockspace is suspended on some nodes before it is on others, or the
  31  * lockspace is enabled on some while still suspended on others.
  32  */
  33
  34 void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_message *ms)
  35 {
  36         struct rq_entry *e;
  37         int length = ms->m_header.h_length - sizeof(struct dlm_message);
  38
  39         e = kmalloc(sizeof(struct rq_entry) + length, GFP_NOFS);
  40         if (!e) {
  41                 log_print("dlm_add_requestqueue: out of memory len %d", length);
  42                 return;
  43         }
  44
  45         e->recover_seq = ls->ls_recover_seq & 0xFFFFFFFF;
  46         e->nodeid = nodeid;
  47         memcpy(&e->request, ms, ms->m_header.h_length);
  48
  49         mutex_lock(&ls->ls_requestqueue_mutex);
  50         list_add_tail(&e->list, &ls->ls_requestqueue);
  51         mutex_unlock(&ls->ls_requestqueue_mutex);
  52 }
  53
  54 /*
  55  * Called by dlm_recoverd to process normal messages saved while recovery was
  56  * happening.  Normal locking has been enabled before this is called.  dlm_recv
  57  * upon receiving a message, will wait for all saved messages to be drained
  58  * here before processing the message it got.  If a new dlm_ls_stop() arrives
  59  * while we're processing these saved messages, it may block trying to suspend
  60  * dlm_recv if dlm_recv is waiting for us in dlm_wait_requestqueue.  In that
  61  * case, we don't abort since locking_stopped is still 0.  If dlm_recv is not
  62  * waiting for us, then this processing may be aborted due to locking_stopped.
  63  */
  64
  65 int dlm_process_requestqueue(struct dlm_ls *ls)
  66 {
  67         struct rq_entry *e;
  68         struct dlm_message *ms;
  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                 ms = &e->request;
  83
  84                 log_limit(ls, "dlm_process_requestqueue msg %d from %d "
  85                           "lkid %x remid %x result %d seq %u",
  86                           ms->m_type, ms->m_header.h_nodeid,
  87                           ms->m_lkid, ms->m_remid, ms->m_result,
  88                           e->recover_seq);
  89
  90                 dlm_receive_message_saved(ls, &e->request, e->recover_seq);
  91
  92                 mutex_lock(&ls->ls_requestqueue_mutex);
  93                 list_del(&e->list);
  94                 kfree(e);
  95
  96                 if (dlm_locking_stopped(ls)) {
  97                         log_debug(ls, "process_requestqueue abort running");
  98                         mutex_unlock(&ls->ls_requestqueue_mutex);
  99                         error = -EINTR;
 100                         break;
 101                 }
 102                 schedule();
 103         }
 104
 105         return error;
 106 }
 107
 108 /*
 109  * After recovery is done, locking is resumed and dlm_recoverd takes all the
 110  * saved requests and processes them as they would have been by dlm_recv.  At
 111  * the same time, dlm_recv will start receiving new requests from remote nodes.
 112  * We want to delay dlm_recv processing new requests until dlm_recoverd has
 113  * finished processing the old saved requests.  We don't check for locking
 114  * stopped here because dlm_ls_stop won't stop locking until it's suspended us
 115  * (dlm_recv).
 116  */
 117
 118 void dlm_wait_requestqueue(struct dlm_ls *ls)
 119 {
 120         for (;;) {
 121                 mutex_lock(&ls->ls_requestqueue_mutex);
 122                 if (list_empty(&ls->ls_requestqueue))
 123                         break;
 124                 mutex_unlock(&ls->ls_requestqueue_mutex);
 125                 schedule();
 126         }
 127         mutex_unlock(&ls->ls_requestqueue_mutex);
 128 }
 129
 130 static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid)
 131 {
 132         uint32_t type = ms->m_type;
 133
 134         /* the ls is being cleaned up and freed by release_lockspace */
 135         if (!ls->ls_count)
 136                 return 1;
 137
 138         if (dlm_is_removed(ls, nodeid))
 139                 return 1;
 140
 141         /* directory operations are always purged because the directory is
 142            always rebuilt during recovery and the lookups resent */
 143
 144         if (type == DLM_MSG_REMOVE ||
 145             type == DLM_MSG_LOOKUP ||
 146             type == DLM_MSG_LOOKUP_REPLY)
 147                 return 1;
 148
 149         if (!dlm_no_directory(ls))
 150                 return 0;
 151
 152         return 1;
 153 }
 154
 155 void dlm_purge_requestqueue(struct dlm_ls *ls)
 156 {
 157         struct dlm_message *ms;
 158         struct rq_entry *e, *safe;
 159
 160         mutex_lock(&ls->ls_requestqueue_mutex);
 161         list_for_each_entry_safe(e, safe, &ls->ls_requestqueue, list) {
 162                 ms =  &e->request;
 163
 164                 if (purge_request(ls, ms, e->nodeid)) {
 165                         list_del(&e->list);
 166                         kfree(e);
 167                 }
 168         }
 169         mutex_unlock(&ls->ls_requestqueue_mutex);
 170 }
 171