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 <lustre_net.h>
  37 # include <lustre_lib.h>
  38
  39 #include <lustre_ha.h>
  40 #include <obd_class.h>   /* for obd_zombie */
  41 #include <obd_support.h> /* for OBD_FAIL_CHECK */
  42 #include <lprocfs_status.h>
  43
  44 #define LIOD_STOP 0
  45 struct ptlrpcd_ctl {
  46         unsigned long             pc_flags;
  47         spinlock_t                pc_lock;
  48         struct completion         pc_starting;
  49         struct completion         pc_finishing;
  50         struct ptlrpc_request_set *pc_set;
  51         char                      pc_name[16];
  52 #ifndef __KERNEL__
  53         int                       pc_recurred;
  54         void                     *pc_callback;
  55         void                     *pc_wait_callback;
  56         void                     *pc_idle_callback;
  57 #endif
  58 };
  59
  60 static struct ptlrpcd_ctl ptlrpcd_pc;
  61 static struct ptlrpcd_ctl ptlrpcd_recovery_pc;
  62
  63 struct semaphore ptlrpcd_sem;
  64 static int ptlrpcd_users = 0;
  65
  66 void ptlrpcd_wake(struct ptlrpc_request *req)
  67 {
  68         struct ptlrpc_request_set *rq_set = req->rq_set;
  69
  70         LASSERT(rq_set != NULL);
  71
  72         cfs_waitq_signal(&rq_set->set_waitq);
  73 }
  74
  75 /* requests that are added to the ptlrpcd queue are sent via
  76  * ptlrpcd_check->ptlrpc_check_set() */
  77 void ptlrpcd_add_req(struct ptlrpc_request *req)
  78 {
  79         struct ptlrpcd_ctl *pc;
  80
  81         if (req->rq_send_state == LUSTRE_IMP_FULL)
  82                 pc = &ptlrpcd_pc;
  83         else
  84                 pc = &ptlrpcd_recovery_pc;
  85
  86         ptlrpc_set_add_new_req(pc->pc_set, req);
  87         cfs_waitq_signal(&pc->pc_set->set_waitq);
  88 }
  89
  90 static int ptlrpcd_check(struct ptlrpcd_ctl *pc)
  91 {
  92         struct list_head *tmp, *pos;
  93         struct ptlrpc_request *req;
  94         int rc = 0;
  95         ENTRY;
  96
  97         if (test_bit(LIOD_STOP, &pc->pc_flags))
  98                 RETURN(1);
  99
 100         spin_lock(&pc->pc_set->set_new_req_lock);
 101         list_for_each_safe(pos, tmp, &pc->pc_set->set_new_requests) {
 102                 req = list_entry(pos, struct ptlrpc_request, rq_set_chain);
 103                 list_del_init(&req->rq_set_chain);
 104                 ptlrpc_set_add_req(pc->pc_set, req);
 105                 rc = 1; /* need to calculate its timeout */
 106         }
 107         spin_unlock(&pc->pc_set->set_new_req_lock);
 108
 109         if (pc->pc_set->set_remaining) {
 110                 rc = rc | ptlrpc_check_set(pc->pc_set);
 111
 112                 /* XXX our set never completes, so we prune the completed
 113                  * reqs after each iteration. boy could this be smarter. */
 114                 list_for_each_safe(pos, tmp, &pc->pc_set->set_requests) {
 115                         req = list_entry(pos, struct ptlrpc_request,
 116                                          rq_set_chain);
 117                         if (req->rq_phase != RQ_PHASE_COMPLETE)
 118                                 continue;
 119
 120                         list_del_init(&req->rq_set_chain);
 121                         req->rq_set = NULL;
 122                         ptlrpc_req_finished (req);
 123                 }
 124         }
 125
 126         if (rc == 0) {
 127                 /* If new requests have been added, make sure to wake up */
 128                 spin_lock(&pc->pc_set->set_new_req_lock);
 129                 rc = !list_empty(&pc->pc_set->set_new_requests);
 130                 spin_unlock(&pc->pc_set->set_new_req_lock);
 131         }
 132
 133         RETURN(rc);
 134 }
 135
 136 #ifdef __KERNEL__
 137 /* ptlrpc's code paths like to execute in process context, so we have this
 138  * thread which spins on a set which contains the io rpcs.  llite specifies
 139  * ptlrpcd's set when it pushes pages down into the oscs */
 140 static int ptlrpcd(void *arg)
 141 {
 142         struct ptlrpcd_ctl *pc = arg;
 143         int rc;
 144         ENTRY;
 145
 146         if ((rc = cfs_daemonize_ctxt(pc->pc_name))) {
 147                 complete(&pc->pc_starting);
 148                 return rc;
 149         }
 150
 151         complete(&pc->pc_starting);
 152
 153         /* this mainloop strongly resembles ptlrpc_set_wait except
 154          * that our set never completes.  ptlrpcd_check calls ptlrpc_check_set
 155          * when there are requests in the set.  new requests come in
 156          * on the set's new_req_list and ptlrpcd_check moves them into
 157          * the set. */
 158         while (1) {
 159                 struct l_wait_info lwi;
 160                 cfs_duration_t timeout;
 161
 162                 timeout = cfs_time_seconds(ptlrpc_set_next_timeout(pc->pc_set));
 163                 lwi = LWI_TIMEOUT(timeout, ptlrpc_expired_set, pc->pc_set);
 164
 165                 l_wait_event(pc->pc_set->set_waitq, ptlrpcd_check(pc), &lwi);
 166
 167                 if (test_bit(LIOD_STOP, &pc->pc_flags))
 168                         break;
 169         }
 170         /* wait for inflight requests to drain */
 171         if (!list_empty(&pc->pc_set->set_requests))
 172                 ptlrpc_set_wait(pc->pc_set);
 173         complete(&pc->pc_finishing);
 174         return 0;
 175 }
 176
 177 #else
 178
 179 int ptlrpcd_check_async_rpcs(void *arg)
 180 {
 181         struct ptlrpcd_ctl *pc = arg;
 182         int                  rc = 0;
 183
 184         /* single threaded!! */
 185         pc->pc_recurred++;
 186
 187         if (pc->pc_recurred == 1) {
 188                 rc = ptlrpcd_check(pc);
 189                 if (!rc)
 190                         ptlrpc_expired_set(pc->pc_set);
 191                 /*XXX send replay requests */
 192                 if (pc == &ptlrpcd_recovery_pc)
 193                         rc = ptlrpcd_check(pc);
 194         }
 195
 196         pc->pc_recurred--;
 197         return rc;
 198 }
 199
 200 int ptlrpcd_idle(void *arg)
 201 {
 202         struct ptlrpcd_ctl *pc = arg;
 203
 204         return (list_empty(&pc->pc_set->set_new_requests) &&
 205                 pc->pc_set->set_remaining == 0);
 206 }
 207
 208 #endif
 209
 210 static int ptlrpcd_start(char *name, struct ptlrpcd_ctl *pc)
 211 {
 212         int rc;
 213
 214         ENTRY;
 215         memset(pc, 0, sizeof(*pc));
 216         init_completion(&pc->pc_starting);
 217         init_completion(&pc->pc_finishing);
 218         pc->pc_flags = 0;
 219         spin_lock_init(&pc->pc_lock);
 220         snprintf (pc->pc_name, sizeof (pc->pc_name), name);
 221
 222         pc->pc_set = ptlrpc_prep_set();
 223         if (pc->pc_set == NULL)
 224                 RETURN(-ENOMEM);
 225
 226 #ifdef __KERNEL__
 227         rc = cfs_kernel_thread(ptlrpcd, pc, 0);
 228         if (rc < 0)  {
 229                 ptlrpc_set_destroy(pc->pc_set);
 230                 RETURN(rc);
 231         }
 232
 233         wait_for_completion(&pc->pc_starting);
 234 #else
 235         pc->pc_wait_callback =
 236                 liblustre_register_wait_callback("ptlrpcd_check_async_rpcs",
 237                                                  &ptlrpcd_check_async_rpcs, pc);
 238         pc->pc_idle_callback =
 239                 liblustre_register_idle_callback("ptlrpcd_check_idle_rpcs",
 240                                                  &ptlrpcd_idle, pc);
 241         (void)rc;
 242 #endif
 243         RETURN(0);
 244 }
 245
 246 static void ptlrpcd_stop(struct ptlrpcd_ctl *pc)
 247 {
 248         set_bit(LIOD_STOP, &pc->pc_flags);
 249         cfs_waitq_signal(&pc->pc_set->set_waitq);
 250 #ifdef __KERNEL__
 251         wait_for_completion(&pc->pc_finishing);
 252 #else
 253         liblustre_deregister_wait_callback(pc->pc_wait_callback);
 254         liblustre_deregister_idle_callback(pc->pc_idle_callback);
 255 #endif
 256         ptlrpc_set_destroy(pc->pc_set);
 257 }
 258
 259 int ptlrpcd_addref(void)
 260 {
 261         int rc = 0;
 262         ENTRY;
 263
 264         mutex_down(&ptlrpcd_sem);
 265         if (++ptlrpcd_users != 1)
 266                 GOTO(out, rc);
 267
 268         rc = ptlrpcd_start("ptlrpcd", &ptlrpcd_pc);
 269         if (rc) {
 270                 --ptlrpcd_users;
 271                 GOTO(out, rc);
 272         }
 273
 274         rc = ptlrpcd_start("ptlrpcd-recov", &ptlrpcd_recovery_pc);
 275         if (rc) {
 276                 ptlrpcd_stop(&ptlrpcd_pc);
 277                 --ptlrpcd_users;
 278                 GOTO(out, rc);
 279         }
 280 out:
 281         mutex_up(&ptlrpcd_sem);
 282         RETURN(rc);
 283 }
 284
 285 void ptlrpcd_decref(void)
 286 {
 287         mutex_down(&ptlrpcd_sem);
 288         if (--ptlrpcd_users == 0) {
 289                 ptlrpcd_stop(&ptlrpcd_pc);
 290                 ptlrpcd_stop(&ptlrpcd_recovery_pc);
 291         }
 292         mutex_up(&ptlrpcd_sem);
 293 }