lustre/ptlrpc/ptlrpcd.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  *  Copyright (C) 2001-2003 Cluster File Systems, Inc.
   5  *   Author Peter Braam <braam@clusterfs.com>
   6  *
   7  *   This file is part of the Lustre file system, http://www.lustre.org
   8  *   Lustre is a trademark of Cluster File Systems, Inc.
   9  *
  10  *   You may have signed or agreed to another license before downloading
  11  *   this software.  If so, you are bound by the terms and conditions
  12  *   of that agreement, and the following does not apply to you.  See the
  13  *   LICENSE file included with this distribution for more information.
  14  *
  15  *   If you did not agree to a different license, then this copy of Lustre
  16  *   is open source software; you can redistribute it and/or modify it
  17  *   under the terms of version 2 of the GNU General Public License as
  18  *   published by the Free Software Foundation.
  19  *
  20  *   In either case, Lustre is distributed in the hope that it will be
  21  *   useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  22  *   of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  *   license text for more details.
  24  *
  25  */
  26
  27 #define DEBUG_SUBSYSTEM S_RPC
  28
  29 #ifdef __KERNEL__
  30 # include <libcfs/libcfs.h>
  31 #else /* __KERNEL__ */
  32 # include <liblustre.h>
  33 # include <ctype.h>
  34 #endif
  35
  36 #include <libcfs/kp30.h>
  37 #include <lustre_net.h>
  38 # include <lustre_lib.h>
  39
  40 #include <lustre_ha.h>
  41 #include <obd_class.h>   /* for obd_zombie */
  42 #include <obd_support.h> /* for OBD_FAIL_CHECK */
  43 #include <lprocfs_status.h>
  44
  45 #define LIOD_STOP 0
  46 struct ptlrpcd_ctl {
  47         unsigned long             pc_flags;
  48         spinlock_t                pc_lock;
  49         struct completion         pc_starting;
  50         struct completion         pc_finishing;
  51         struct ptlrpc_request_set *pc_set;
  52         char                      pc_name[16];
  53 #ifndef __KERNEL__
  54         int                       pc_recurred;
  55         void                     *pc_callback;
  56         void                     *pc_wait_callback;
  57         void                     *pc_idle_callback;
  58 #endif
  59 };
  60
  61 static struct ptlrpcd_ctl ptlrpcd_pc;
  62 static struct ptlrpcd_ctl ptlrpcd_recovery_pc;
  63
  64 struct semaphore ptlrpcd_sem;
  65 static int ptlrpcd_users = 0;
  66
  67 void ptlrpcd_wake(struct ptlrpc_request *req)
  68 {
  69         struct ptlrpc_request_set *rq_set = req->rq_set;
  70
  71         LASSERT(rq_set != NULL);
  72
  73         cfs_waitq_signal(&rq_set->set_waitq);
  74 }
  75
  76 /* requests that are added to the ptlrpcd queue are sent via
  77  * ptlrpcd_check->ptlrpc_check_set() */
  78 void ptlrpcd_add_req(struct ptlrpc_request *req)
  79 {
  80         struct ptlrpcd_ctl *pc;
  81
  82         if (req->rq_send_state == LUSTRE_IMP_FULL)
  83                 pc = &ptlrpcd_pc;
  84         else
  85                 pc = &ptlrpcd_recovery_pc;
  86
  87         ptlrpc_set_add_new_req(pc->pc_set, req);
  88         cfs_waitq_signal(&pc->pc_set->set_waitq);
  89 }
  90
  91 static int ptlrpcd_check(struct ptlrpcd_ctl *pc)
  92 {
  93         struct list_head *tmp, *pos;
  94         struct ptlrpc_request *req;
  95         int rc = 0;
  96         ENTRY;
  97
  98         if (test_bit(LIOD_STOP, &pc->pc_flags))
  99                 RETURN(1);
 100
 101         spin_lock(&pc->pc_set->set_new_req_lock);
 102         list_for_each_safe(pos, tmp, &pc->pc_set->set_new_requests) {
 103                 req = list_entry(pos, struct ptlrpc_request, rq_set_chain);
 104                 list_del_init(&req->rq_set_chain);
 105                 ptlrpc_set_add_req(pc->pc_set, req);
 106                 rc = 1; /* need to calculate its timeout */
 107         }
 108         spin_unlock(&pc->pc_set->set_new_req_lock);
 109
 110         if (pc->pc_set->set_remaining) {
 111                 rc = rc | ptlrpc_check_set(pc->pc_set);
 112
 113                 /* XXX our set never completes, so we prune the completed
 114                  * reqs after each iteration. boy could this be smarter. */
 115                 list_for_each_safe(pos, tmp, &pc->pc_set->set_requests) {
 116                         req = list_entry(pos, struct ptlrpc_request,
 117                                          rq_set_chain);
 118                         if (req->rq_phase != RQ_PHASE_COMPLETE)
 119                                 continue;
 120
 121                         list_del_init(&req->rq_set_chain);
 122                         req->rq_set = NULL;
 123                         ptlrpc_req_finished (req);
 124                 }
 125         }
 126
 127         if (rc == 0) {
 128                 /* If new requests have been added, make sure to wake up */
 129                 spin_lock(&pc->pc_set->set_new_req_lock);
 130                 rc = !list_empty(&pc->pc_set->set_new_requests);
 131                 spin_unlock(&pc->pc_set->set_new_req_lock);
 132         }
 133
 134         RETURN(rc);
 135 }
 136
 137 #ifdef __KERNEL__
 138 /* ptlrpc's code paths like to execute in process context, so we have this
 139  * thread which spins on a set which contains the io rpcs.  llite specifies
 140  * ptlrpcd's set when it pushes pages down into the oscs */
 141 static int ptlrpcd(void *arg)
 142 {
 143         struct ptlrpcd_ctl *pc = arg;
 144         int rc;
 145         ENTRY;
 146
 147         if ((rc = cfs_daemonize_ctxt(pc->pc_name))) {
 148                 complete(&pc->pc_starting);
 149                 return rc;
 150         }
 151
 152         complete(&pc->pc_starting);
 153
 154         /* this mainloop strongly resembles ptlrpc_set_wait except
 155          * that our set never completes.  ptlrpcd_check calls ptlrpc_check_set
 156          * when there are requests in the set.  new requests come in
 157          * on the set's new_req_list and ptlrpcd_check moves them into
 158          * the set. */
 159         while (1) {
 160                 struct l_wait_info lwi;
 161                 cfs_duration_t timeout;
 162
 163                 timeout = cfs_time_seconds(ptlrpc_set_next_timeout(pc->pc_set));
 164                 lwi = LWI_TIMEOUT(timeout, ptlrpc_expired_set, pc->pc_set);
 165
 166                 l_wait_event(pc->pc_set->set_waitq, ptlrpcd_check(pc), &lwi);
 167
 168                 if (test_bit(LIOD_STOP, &pc->pc_flags))
 169                         break;
 170         }
 171         /* wait for inflight requests to drain */
 172         if (!list_empty(&pc->pc_set->set_requests))
 173                 ptlrpc_set_wait(pc->pc_set);
 174         complete(&pc->pc_finishing);
 175         return 0;
 176 }
 177
 178 #else
 179
 180 int ptlrpcd_check_async_rpcs(void *arg)
 181 {
 182         struct ptlrpcd_ctl *pc = arg;
 183         int                  rc = 0;
 184
 185         /* single threaded!! */
 186         pc->pc_recurred++;
 187
 188         if (pc->pc_recurred == 1) {
 189                 rc = ptlrpcd_check(pc);
 190                 if (!rc)
 191                         ptlrpc_expired_set(pc->pc_set);
 192                 /*XXX send replay requests */
 193                 if (pc == &ptlrpcd_recovery_pc)
 194                         rc = ptlrpcd_check(pc);
 195         }
 196
 197         pc->pc_recurred--;
 198         return rc;
 199 }
 200
 201 int ptlrpcd_idle(void *arg)
 202 {
 203         struct ptlrpcd_ctl *pc = arg;
 204
 205         return (list_empty(&pc->pc_set->set_new_requests) &&
 206                 pc->pc_set->set_remaining == 0);
 207 }
 208
 209 #endif
 210
 211 static int ptlrpcd_start(char *name, struct ptlrpcd_ctl *pc)
 212 {
 213         int rc;
 214
 215         ENTRY;
 216         memset(pc, 0, sizeof(*pc));
 217         init_completion(&pc->pc_starting);
 218         init_completion(&pc->pc_finishing);
 219         pc->pc_flags = 0;
 220         spin_lock_init(&pc->pc_lock);
 221         snprintf (pc->pc_name, sizeof (pc->pc_name), name);
 222
 223         pc->pc_set = ptlrpc_prep_set();
 224         if (pc->pc_set == NULL)
 225                 RETURN(-ENOMEM);
 226
 227 #ifdef __KERNEL__
 228         rc = cfs_kernel_thread(ptlrpcd, pc, 0);
 229         if (rc < 0)  {
 230                 ptlrpc_set_destroy(pc->pc_set);
 231                 RETURN(rc);
 232         }
 233
 234         wait_for_completion(&pc->pc_starting);
 235 #else
 236         pc->pc_wait_callback =
 237                 liblustre_register_wait_callback("ptlrpcd_check_async_rpcs",
 238                                                  &ptlrpcd_check_async_rpcs, pc);
 239         pc->pc_idle_callback =
 240                 liblustre_register_idle_callback("ptlrpcd_check_idle_rpcs",
 241                                                  &ptlrpcd_idle, pc);
 242         (void)rc;
 243 #endif
 244         RETURN(0);
 245 }
 246
 247 static void ptlrpcd_stop(struct ptlrpcd_ctl *pc)
 248 {
 249         set_bit(LIOD_STOP, &pc->pc_flags);
 250         cfs_waitq_signal(&pc->pc_set->set_waitq);
 251 #ifdef __KERNEL__
 252         wait_for_completion(&pc->pc_finishing);
 253 #else
 254         liblustre_deregister_wait_callback(pc->pc_wait_callback);
 255         liblustre_deregister_idle_callback(pc->pc_idle_callback);
 256 #endif
 257         ptlrpc_set_destroy(pc->pc_set);
 258 }
 259
 260 int ptlrpcd_addref(void)
 261 {
 262         int rc = 0;
 263         ENTRY;
 264
 265         mutex_down(&ptlrpcd_sem);
 266         if (++ptlrpcd_users != 1)
 267                 GOTO(out, rc);
 268
 269         rc = ptlrpcd_start("ptlrpcd", &ptlrpcd_pc);
 270         if (rc) {
 271                 --ptlrpcd_users;
 272                 GOTO(out, rc);
 273         }
 274
 275         rc = ptlrpcd_start("ptlrpcd-recov", &ptlrpcd_recovery_pc);
 276         if (rc) {
 277                 ptlrpcd_stop(&ptlrpcd_pc);
 278                 --ptlrpcd_users;
 279                 GOTO(out, rc);
 280         }
 281 out:
 282         mutex_up(&ptlrpcd_sem);
 283         RETURN(rc);
 284 }
 285
 286 void ptlrpcd_decref(void)
 287 {
 288         mutex_down(&ptlrpcd_sem);
 289         if (--ptlrpcd_users == 0) {
 290                 ptlrpcd_stop(&ptlrpcd_pc);
 291                 ptlrpcd_stop(&ptlrpcd_recovery_pc);
 292         }
 293         mutex_up(&ptlrpcd_sem);
 294 }