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 list_head          pc_req_list;
  52         cfs_waitq_t               pc_waitq;
  53         struct ptlrpc_request_set *pc_set;
  54         char                      pc_name[16];
  55 #ifndef __KERNEL__
  56         int                       pc_recurred;
  57         void                     *pc_callback;
  58         void                     *pc_wait_callback;
  59         void                     *pc_idle_callback;
  60 #endif
  61 };
  62
  63 static struct ptlrpcd_ctl ptlrpcd_pc;
  64 static struct ptlrpcd_ctl ptlrpcd_recovery_pc;
  65
  66 struct semaphore ptlrpcd_sem;
  67 static int ptlrpcd_users = 0;
  68
  69 void ptlrpcd_wake(struct ptlrpc_request *req)
  70 {
  71         struct ptlrpcd_ctl *pc = req->rq_ptlrpcd_data;
  72
  73         LASSERT(pc != NULL);
  74
  75         cfs_waitq_signal(&pc->pc_waitq);
  76 }
  77
  78 /* requests that are added to the ptlrpcd queue are sent via
  79  * ptlrpcd_check->ptlrpc_check_set() */
  80 void ptlrpcd_add_req(struct ptlrpc_request *req)
  81 {
  82         struct ptlrpcd_ctl *pc;
  83
  84         if (req->rq_send_state == LUSTRE_IMP_FULL)
  85                 pc = &ptlrpcd_pc;
  86         else
  87                 pc = &ptlrpcd_recovery_pc;
  88
  89         req->rq_ptlrpcd_data = pc;
  90         ptlrpc_set_add_new_req(pc->pc_set, req);
  91         wake_up(&pc->pc_waitq);
  92 }
  93
  94 static int ptlrpcd_check(struct ptlrpcd_ctl *pc)
  95 {
  96         struct list_head *tmp, *pos;
  97         struct ptlrpc_request *req;
  98         int rc = 0;
  99         ENTRY;
 100
 101         if (test_bit(LIOD_STOP, &pc->pc_flags))
 102                 RETURN(1);
 103
 104         obd_zombie_impexp_cull();
 105
 106         spin_lock(&pc->pc_set->set_new_req_lock);
 107         list_for_each_safe(pos, tmp, &pc->pc_set->set_new_requests) {
 108                 req = list_entry(pos, struct ptlrpc_request, rq_set_chain);
 109                 list_del_init(&req->rq_set_chain);
 110                 ptlrpc_set_add_req(pc->pc_set, req);
 111                 rc = 1; /* need to calculate its timeout */
 112         }
 113         spin_unlock(&pc->pc_set->set_new_req_lock);
 114
 115         if (pc->pc_set->set_remaining) {
 116                 rc = rc | ptlrpc_check_set(pc->pc_set);
 117
 118                 /* XXX our set never completes, so we prune the completed
 119                  * reqs after each iteration. boy could this be smarter. */
 120                 list_for_each_safe(pos, tmp, &pc->pc_set->set_requests) {
 121                         req = list_entry(pos, struct ptlrpc_request,
 122                                          rq_set_chain);
 123                         if (req->rq_phase != RQ_PHASE_COMPLETE)
 124                                 continue;
 125
 126                         list_del_init(&req->rq_set_chain);
 127                         req->rq_set = NULL;
 128                         ptlrpc_req_finished (req);
 129                 }
 130         }
 131
 132         if (rc == 0) {
 133                 /* If new requests have been added, make sure to wake up */
 134                 spin_lock(&pc->pc_set->set_new_req_lock);
 135                 rc = !list_empty(&pc->pc_set->set_new_requests);
 136                 spin_unlock(&pc->pc_set->set_new_req_lock);
 137         }
 138
 139         RETURN(rc);
 140 }
 141
 142 #ifdef __KERNEL__
 143 /* ptlrpc's code paths like to execute in process context, so we have this
 144  * thread which spins on a set which contains the io rpcs.  llite specifies
 145  * ptlrpcd's set when it pushes pages down into the oscs */
 146 static int ptlrpcd(void *arg)
 147 {
 148         struct ptlrpcd_ctl *pc = arg;
 149         int rc;
 150         ENTRY;
 151
 152         if ((rc = cfs_daemonize_ctxt(pc->pc_name))) {
 153                 complete(&pc->pc_starting);
 154                 return rc;
 155         }
 156
 157         complete(&pc->pc_starting);
 158
 159         /* this mainloop strongly resembles ptlrpc_set_wait except
 160          * that our set never completes.  ptlrpcd_check calls ptlrpc_check_set
 161          * when there are requests in the set.  new requests come in
 162          * on the set's new_req_list and ptlrpcd_check moves them into
 163          * the set. */
 164         while (1) {
 165                 cfs_waitlink_t set_wait;
 166                 struct l_wait_info lwi;
 167                 cfs_duration_t timeout;
 168
 169                 timeout = cfs_time_seconds(ptlrpc_set_next_timeout(pc->pc_set));
 170                 lwi = LWI_TIMEOUT(timeout, ptlrpc_expired_set, pc->pc_set);
 171
 172                 /* ala the pinger, wait on pc's waitqueue and the set's */
 173                 cfs_waitlink_init(&set_wait);
 174                 cfs_waitq_add(&pc->pc_set->set_waitq, &set_wait);
 175                 cfs_waitq_forward(&set_wait, &pc->pc_waitq);
 176                 l_wait_event(pc->pc_waitq, ptlrpcd_check(pc), &lwi);
 177                 cfs_waitq_del(&pc->pc_set->set_waitq, &set_wait);
 178
 179                 if (test_bit(LIOD_STOP, &pc->pc_flags))
 180                         break;
 181         }
 182         /* wait for inflight requests to drain */
 183         if (!list_empty(&pc->pc_set->set_requests))
 184                 ptlrpc_set_wait(pc->pc_set);
 185         complete(&pc->pc_finishing);
 186         return 0;
 187 }
 188
 189 static void ptlrpcd_zombie_impexp_notify(void)
 190 {
 191         cfs_waitq_signal(&ptlrpcd_pc.pc_waitq);
 192 }
 193 #else
 194
 195 int ptlrpcd_check_async_rpcs(void *arg)
 196 {
 197         struct ptlrpcd_ctl *pc = arg;
 198         int                  rc = 0;
 199
 200         /* single threaded!! */
 201         pc->pc_recurred++;
 202
 203         if (pc->pc_recurred == 1) {
 204                 rc = ptlrpcd_check(pc);
 205                 if (!rc)
 206                         ptlrpc_expired_set(pc->pc_set);
 207                 /*XXX send replay requests */
 208                 if (pc == &ptlrpcd_recovery_pc)
 209                         rc = ptlrpcd_check(pc);
 210         }
 211
 212         pc->pc_recurred--;
 213         return rc;
 214 }
 215
 216 int ptlrpcd_idle(void *arg)
 217 {
 218         struct ptlrpcd_ctl *pc = arg;
 219
 220         return (list_empty(&pc->pc_set->set_new_requests) &&
 221                 pc->pc_set->set_remaining == 0);
 222 }
 223
 224 #endif
 225
 226 static int ptlrpcd_start(char *name, struct ptlrpcd_ctl *pc)
 227 {
 228         int rc;
 229
 230         ENTRY;
 231         memset(pc, 0, sizeof(*pc));
 232         init_completion(&pc->pc_starting);
 233         init_completion(&pc->pc_finishing);
 234         cfs_waitq_init(&pc->pc_waitq);
 235         pc->pc_flags = 0;
 236         spin_lock_init(&pc->pc_lock);
 237         CFS_INIT_LIST_HEAD(&pc->pc_req_list);
 238         snprintf (pc->pc_name, sizeof (pc->pc_name), name);
 239
 240         pc->pc_set = ptlrpc_prep_set();
 241         if (pc->pc_set == NULL)
 242                 RETURN(-ENOMEM);
 243
 244 #ifdef __KERNEL__
 245         /* wake ptlrpcd when zombie imports or exports exist */
 246         obd_zombie_impexp_notify = ptlrpcd_zombie_impexp_notify;
 247
 248         rc = cfs_kernel_thread(ptlrpcd, pc, 0);
 249         if (rc < 0)  {
 250                 ptlrpc_set_destroy(pc->pc_set);
 251                 RETURN(rc);
 252         }
 253
 254         wait_for_completion(&pc->pc_starting);
 255 #else
 256         pc->pc_wait_callback =
 257                 liblustre_register_wait_callback("ptlrpcd_check_async_rpcs",
 258                                                  &ptlrpcd_check_async_rpcs, pc);
 259         pc->pc_idle_callback =
 260                 liblustre_register_idle_callback("ptlrpcd_check_idle_rpcs",
 261                                                  &ptlrpcd_idle, pc);
 262         (void)rc;
 263 #endif
 264         RETURN(0);
 265 }
 266
 267 static void ptlrpcd_stop(struct ptlrpcd_ctl *pc)
 268 {
 269         set_bit(LIOD_STOP, &pc->pc_flags);
 270         cfs_waitq_signal(&pc->pc_waitq);
 271 #ifdef __KERNEL__
 272         obd_zombie_impexp_notify = NULL;
 273         wait_for_completion(&pc->pc_finishing);
 274 #else
 275         liblustre_deregister_wait_callback(pc->pc_wait_callback);
 276         liblustre_deregister_idle_callback(pc->pc_idle_callback);
 277 #endif
 278         ptlrpc_set_destroy(pc->pc_set);
 279 }
 280
 281 int ptlrpcd_addref(void)
 282 {
 283         int rc = 0;
 284         ENTRY;
 285
 286         mutex_down(&ptlrpcd_sem);
 287         if (++ptlrpcd_users != 1)
 288                 GOTO(out, rc);
 289
 290         rc = ptlrpcd_start("ptlrpcd", &ptlrpcd_pc);
 291         if (rc) {
 292                 --ptlrpcd_users;
 293                 GOTO(out, rc);
 294         }
 295
 296         rc = ptlrpcd_start("ptlrpcd-recov", &ptlrpcd_recovery_pc);
 297         if (rc) {
 298                 ptlrpcd_stop(&ptlrpcd_pc);
 299                 --ptlrpcd_users;
 300                 GOTO(out, rc);
 301         }
 302 out:
 303         mutex_up(&ptlrpcd_sem);
 304         RETURN(rc);
 305 }
 306
 307 void ptlrpcd_decref(void)
 308 {
 309         mutex_down(&ptlrpcd_sem);
 310         if (--ptlrpcd_users == 0) {
 311                 ptlrpcd_stop(&ptlrpcd_pc);
 312                 ptlrpcd_stop(&ptlrpcd_recovery_pc);
 313         }
 314         mutex_up(&ptlrpcd_sem);
 315 }