LXR linux/fs/dlm/ast.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/******************************************************************************
   3*******************************************************************************
   4**
   5**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
   6**  Copyright (C) 2004-2010 Red Hat, Inc.  All rights reserved.
   7**
   8**
   9*******************************************************************************
  10******************************************************************************/
  11
  12#include "dlm_internal.h"
  13#include "lock.h"
  14#include "user.h"
  15#include "ast.h"
  16
  17static uint64_t dlm_cb_seq;
  18static DEFINE_SPINLOCK(dlm_cb_seq_spin);
  19
  20static void dlm_dump_lkb_callbacks(struct dlm_lkb *lkb)
  21{
  22        int i;
  23
  24        log_print("last_bast %x %llu flags %x mode %d sb %d %x",
  25                  lkb->lkb_id,
  26                  (unsigned long long)lkb->lkb_last_bast.seq,
  27                  lkb->lkb_last_bast.flags,
  28                  lkb->lkb_last_bast.mode,
  29                  lkb->lkb_last_bast.sb_status,
  30                  lkb->lkb_last_bast.sb_flags);
  31
  32        log_print("last_cast %x %llu flags %x mode %d sb %d %x",
  33                  lkb->lkb_id,
  34                  (unsigned long long)lkb->lkb_last_cast.seq,
  35                  lkb->lkb_last_cast.flags,
  36                  lkb->lkb_last_cast.mode,
  37                  lkb->lkb_last_cast.sb_status,
  38                  lkb->lkb_last_cast.sb_flags);
  39
  40        for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
  41                log_print("cb %x %llu flags %x mode %d sb %d %x",
  42                          lkb->lkb_id,
  43                          (unsigned long long)lkb->lkb_callbacks[i].seq,
  44                          lkb->lkb_callbacks[i].flags,
  45                          lkb->lkb_callbacks[i].mode,
  46                          lkb->lkb_callbacks[i].sb_status,
  47                          lkb->lkb_callbacks[i].sb_flags);
  48        }
  49}
  50
  51int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
  52                         int status, uint32_t sbflags, uint64_t seq)
  53{
  54        struct dlm_ls *ls = lkb->lkb_resource->res_ls;
  55        uint64_t prev_seq;
  56        int prev_mode;
  57        int i, rv;
  58
  59        for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
  60                if (lkb->lkb_callbacks[i].seq)
  61                        continue;
  62
  63                /*
  64                 * Suppress some redundant basts here, do more on removal.
  65                 * Don't even add a bast if the callback just before it
  66                 * is a bast for the same mode or a more restrictive mode.
  67                 * (the addional > PR check is needed for PR/CW inversion)
  68                 */
  69
  70                if ((i > 0) && (flags & DLM_CB_BAST) &&
  71                    (lkb->lkb_callbacks[i-1].flags & DLM_CB_BAST)) {
  72
  73                        prev_seq = lkb->lkb_callbacks[i-1].seq;
  74                        prev_mode = lkb->lkb_callbacks[i-1].mode;
  75
  76                        if ((prev_mode == mode) ||
  77                            (prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
  78
  79                                log_debug(ls, "skip %x add bast %llu mode %d "
  80                                          "for bast %llu mode %d",
  81                                          lkb->lkb_id,
  82                                          (unsigned long long)seq,
  83                                          mode,
  84                                          (unsigned long long)prev_seq,
  85                                          prev_mode);
  86                                rv = 0;
  87                                goto out;
  88                        }
  89                }
  90
  91                lkb->lkb_callbacks[i].seq = seq;
  92                lkb->lkb_callbacks[i].flags = flags;
  93                lkb->lkb_callbacks[i].mode = mode;
  94                lkb->lkb_callbacks[i].sb_status = status;
  95                lkb->lkb_callbacks[i].sb_flags = (sbflags & 0x000000FF);
  96                rv = 0;
  97                break;
  98        }
  99
 100        if (i == DLM_CALLBACKS_SIZE) {
 101                log_error(ls, "no callbacks %x %llu flags %x mode %d sb %d %x",
 102                          lkb->lkb_id, (unsigned long long)seq,
 103                          flags, mode, status, sbflags);
 104                dlm_dump_lkb_callbacks(lkb);
 105                rv = -1;
 106                goto out;
 107        }
 108 out:
 109        return rv;
 110}
 111
 112int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
 113                         struct dlm_callback *cb, int *resid)
 114{
 115        int i, rv;
 116
 117        *resid = 0;
 118
 119        if (!lkb->lkb_callbacks[0].seq) {
 120                rv = -ENOENT;
 121                goto out;
 122        }
 123
 124        /* oldest undelivered cb is callbacks[0] */
 125
 126        memcpy(cb, &lkb->lkb_callbacks[0], sizeof(struct dlm_callback));
 127        memset(&lkb->lkb_callbacks[0], 0, sizeof(struct dlm_callback));
 128
 129        /* shift others down */
 130
 131        for (i = 1; i < DLM_CALLBACKS_SIZE; i++) {
 132                if (!lkb->lkb_callbacks[i].seq)
 133                        break;
 134                memcpy(&lkb->lkb_callbacks[i-1], &lkb->lkb_callbacks[i],
 135                       sizeof(struct dlm_callback));
 136                memset(&lkb->lkb_callbacks[i], 0, sizeof(struct dlm_callback));
 137                (*resid)++;
 138        }
 139
 140        /* if cb is a bast, it should be skipped if the blocking mode is
 141           compatible with the last granted mode */
 142
 143        if ((cb->flags & DLM_CB_BAST) && lkb->lkb_last_cast.seq) {
 144                if (dlm_modes_compat(cb->mode, lkb->lkb_last_cast.mode)) {
 145                        cb->flags |= DLM_CB_SKIP;
 146
 147                        log_debug(ls, "skip %x bast %llu mode %d "
 148                                  "for cast %llu mode %d",
 149                                  lkb->lkb_id,
 150                                  (unsigned long long)cb->seq,
 151                                  cb->mode,
 152                                  (unsigned long long)lkb->lkb_last_cast.seq,
 153                                  lkb->lkb_last_cast.mode);
 154                        rv = 0;
 155                        goto out;
 156                }
 157        }
 158
 159        if (cb->flags & DLM_CB_CAST) {
 160                memcpy(&lkb->lkb_last_cast, cb, sizeof(struct dlm_callback));
 161                lkb->lkb_last_cast_time = ktime_get();
 162        }
 163
 164        if (cb->flags & DLM_CB_BAST) {
 165                memcpy(&lkb->lkb_last_bast, cb, sizeof(struct dlm_callback));
 166                lkb->lkb_last_bast_time = ktime_get();
 167        }
 168        rv = 0;
 169 out:
 170        return rv;
 171}
 172
 173void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
 174                uint32_t sbflags)
 175{
 176        struct dlm_ls *ls = lkb->lkb_resource->res_ls;
 177        uint64_t new_seq, prev_seq;
 178        int rv;
 179
 180        spin_lock(&dlm_cb_seq_spin);
 181        new_seq = ++dlm_cb_seq;
 182        if (!dlm_cb_seq)
 183                new_seq = ++dlm_cb_seq;
 184        spin_unlock(&dlm_cb_seq_spin);
 185
 186        if (lkb->lkb_flags & DLM_IFL_USER) {
 187                dlm_user_add_ast(lkb, flags, mode, status, sbflags, new_seq);
 188                return;
 189        }
 190
 191        mutex_lock(&lkb->lkb_cb_mutex);
 192        prev_seq = lkb->lkb_callbacks[0].seq;
 193
 194        rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, new_seq);
 195        if (rv < 0)
 196                goto out;
 197
 198        if (!prev_seq) {
 199                kref_get(&lkb->lkb_ref);
 200
 201                if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
 202                        mutex_lock(&ls->ls_cb_mutex);
 203                        list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
 204                        mutex_unlock(&ls->ls_cb_mutex);
 205                } else {
 206                        queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
 207                }
 208        }
 209 out:
 210        mutex_unlock(&lkb->lkb_cb_mutex);
 211}
 212
 213void dlm_callback_work(struct work_struct *work)
 214{
 215        struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
 216        struct dlm_ls *ls = lkb->lkb_resource->res_ls;
 217        void (*castfn) (void *astparam);
 218        void (*bastfn) (void *astparam, int mode);
 219        struct dlm_callback callbacks[DLM_CALLBACKS_SIZE];
 220        int i, rv, resid;
 221
 222        memset(&callbacks, 0, sizeof(callbacks));
 223
 224        mutex_lock(&lkb->lkb_cb_mutex);
 225        if (!lkb->lkb_callbacks[0].seq) {
 226                /* no callback work exists, shouldn't happen */
 227                log_error(ls, "dlm_callback_work %x no work", lkb->lkb_id);
 228                dlm_print_lkb(lkb);
 229                dlm_dump_lkb_callbacks(lkb);
 230        }
 231
 232        for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
 233                rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
 234                if (rv < 0)
 235                        break;
 236        }
 237
 238        if (resid) {
 239                /* cbs remain, loop should have removed all, shouldn't happen */
 240                log_error(ls, "dlm_callback_work %x resid %d", lkb->lkb_id,
 241                          resid);
 242                dlm_print_lkb(lkb);
 243                dlm_dump_lkb_callbacks(lkb);
 244        }
 245        mutex_unlock(&lkb->lkb_cb_mutex);
 246
 247        castfn = lkb->lkb_astfn;
 248        bastfn = lkb->lkb_bastfn;
 249
 250        for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
 251                if (!callbacks[i].seq)
 252                        break;
 253                if (callbacks[i].flags & DLM_CB_SKIP) {
 254                        continue;
 255                } else if (callbacks[i].flags & DLM_CB_BAST) {
 256                        bastfn(lkb->lkb_astparam, callbacks[i].mode);
 257                } else if (callbacks[i].flags & DLM_CB_CAST) {
 258                        lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
 259                        lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
 260                        castfn(lkb->lkb_astparam);
 261                }
 262        }
 263
 264        /* undo kref_get from dlm_add_callback, may cause lkb to be freed */
 265        dlm_put_lkb(lkb);
 266}
 267
 268int dlm_callback_start(struct dlm_ls *ls)
 269{
 270        ls->ls_callback_wq = alloc_workqueue("dlm_callback",
 271                                             WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
 272        if (!ls->ls_callback_wq) {
 273                log_print("can't start dlm_callback workqueue");
 274                return -ENOMEM;
 275        }
 276        return 0;
 277}
 278
 279void dlm_callback_stop(struct dlm_ls *ls)
 280{
 281        if (ls->ls_callback_wq)
 282                destroy_workqueue(ls->ls_callback_wq);
 283}
 284
 285void dlm_callback_suspend(struct dlm_ls *ls)
 286{
 287        set_bit(LSFL_CB_DELAY, &ls->ls_flags);
 288
 289        if (ls->ls_callback_wq)
 290                flush_workqueue(ls->ls_callback_wq);
 291}
 292
 293#define MAX_CB_QUEUE 25
 294
 295void dlm_callback_resume(struct dlm_ls *ls)
 296{
 297        struct dlm_lkb *lkb, *safe;
 298        int count = 0;
 299
 300        clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
 301
 302        if (!ls->ls_callback_wq)
 303                return;
 304
 305more:
 306        mutex_lock(&ls->ls_cb_mutex);
 307        list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
 308                list_del_init(&lkb->lkb_cb_list);
 309                queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
 310                count++;
 311                if (count == MAX_CB_QUEUE)
 312                        break;
 313        }
 314        mutex_unlock(&ls->ls_cb_mutex);
 315
 316        if (count)
 317                log_rinfo(ls, "dlm_callback_resume %d", count);
 318        if (count == MAX_CB_QUEUE) {
 319                count = 0;
 320                cond_resched();
 321                goto more;
 322        }
 323}
 324
 325