lustre/lvfs/upcall_cache.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * GPL HEADER START
   5  *
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License version 2 for more details (a copy is included
  16  * in the LICENSE file that accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * version 2 along with this program; If not, see [sun.com URL with a
  20  * copy of GPLv2].
  21  *
  22  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  23  * CA 95054 USA or visit www.sun.com if you need additional information or
  24  * have any questions.
  25  *
  26  * GPL HEADER END
  27  */
  28 /*
  29  * Copyright  2008 Sun Microsystems, Inc. All rights reserved
  30  * Use is subject to license terms.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/lvfs/upcall_cache.c
  37  *
  38  * Supplementary groups cache.
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_SEC
  42
  43 #ifndef AUTOCONF_INCLUDED
  44 #include <linux/config.h>
  45 #endif
  46 #include <linux/module.h>
  47 #include <linux/kernel.h>
  48 #include <linux/mm.h>
  49 #include <linux/kmod.h>
  50 #include <linux/string.h>
  51 #include <linux/stat.h>
  52 #include <linux/errno.h>
  53 #include <linux/version.h>
  54 #include <linux/unistd.h>
  55
  56 #include <asm/system.h>
  57 #include <asm/uaccess.h>
  58
  59 #include <linux/fs.h>
  60 #include <linux/stat.h>
  61 #include <asm/uaccess.h>
  62 #include <linux/slab.h>
  63
  64 #include <obd_support.h>
  65 #include <lustre_lib.h>
  66
  67 static struct upcall_cache_entry *alloc_entry(struct upcall_cache *cache,
  68                                               __u64 key, void *args)
  69 {
  70         struct upcall_cache_entry *entry;
  71
  72         OBD_ALLOC_PTR(entry);
  73         if (!entry)
  74                 return NULL;
  75
  76         UC_CACHE_SET_NEW(entry);
  77         INIT_LIST_HEAD(&entry->ue_hash);
  78         entry->ue_key = key;
  79         atomic_set(&entry->ue_refcount, 0);
  80         init_waitqueue_head(&entry->ue_waitq);
  81         if (cache->uc_ops->init_entry)
  82                 cache->uc_ops->init_entry(entry, args);
  83         return entry;
  84 }
  85
  86 /* protected by cache lock */
  87 static void free_entry(struct upcall_cache *cache,
  88                        struct upcall_cache_entry *entry)
  89 {
  90         if (cache->uc_ops->free_entry)
  91                 cache->uc_ops->free_entry(cache, entry);
  92
  93         list_del(&entry->ue_hash);
  94         CDEBUG(D_OTHER, "destroy cache entry %p for key "LPU64"\n",
  95                entry, entry->ue_key);
  96         OBD_FREE_PTR(entry);
  97 }
  98
  99 static inline int upcall_compare(struct upcall_cache *cache,
 100                                  struct upcall_cache_entry *entry,
 101                                  __u64 key, void *args)
 102 {
 103         if (entry->ue_key != key)
 104                 return -1;
 105
 106         if (cache->uc_ops->upcall_compare)
 107                 return cache->uc_ops->upcall_compare(cache, entry, key, args);
 108
 109         return 0;
 110 }
 111
 112 static inline int downcall_compare(struct upcall_cache *cache,
 113                                    struct upcall_cache_entry *entry,
 114                                    __u64 key, void *args)
 115 {
 116         if (entry->ue_key != key)
 117                 return -1;
 118
 119         if (cache->uc_ops->downcall_compare)
 120                 return cache->uc_ops->downcall_compare(cache, entry, key, args);
 121
 122         return 0;
 123 }
 124
 125 static inline void get_entry(struct upcall_cache_entry *entry)
 126 {
 127         atomic_inc(&entry->ue_refcount);
 128 }
 129
 130 static inline void put_entry(struct upcall_cache *cache,
 131                              struct upcall_cache_entry *entry)
 132 {
 133         if (atomic_dec_and_test(&entry->ue_refcount) &&
 134             (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry))) {
 135                 free_entry(cache, entry);
 136         }
 137 }
 138
 139 static int check_unlink_entry(struct upcall_cache *cache,
 140                               struct upcall_cache_entry *entry)
 141 {
 142         if (UC_CACHE_IS_VALID(entry) &&
 143             time_before(jiffies, entry->ue_expire))
 144                 return 0;
 145
 146         if (UC_CACHE_IS_ACQUIRING(entry)) {
 147                 if (time_before(jiffies, entry->ue_acquire_expire))
 148                         return 0;
 149
 150                 UC_CACHE_SET_EXPIRED(entry);
 151                 wake_up_all(&entry->ue_waitq);
 152         } else if (!UC_CACHE_IS_INVALID(entry)) {
 153                 UC_CACHE_SET_EXPIRED(entry);
 154         }
 155
 156         list_del_init(&entry->ue_hash);
 157         if (!atomic_read(&entry->ue_refcount))
 158                 free_entry(cache, entry);
 159         return 1;
 160 }
 161
 162 static inline int refresh_entry(struct upcall_cache *cache,
 163                          struct upcall_cache_entry *entry)
 164 {
 165         LASSERT(cache->uc_ops->do_upcall);
 166         return cache->uc_ops->do_upcall(cache, entry);
 167 }
 168
 169 struct upcall_cache_entry *upcall_cache_get_entry(struct upcall_cache *cache,
 170                                                   __u64 key, void *args)
 171 {
 172         struct upcall_cache_entry *entry = NULL, *new = NULL, *next;
 173         struct list_head *head;
 174         wait_queue_t wait;
 175         int rc, found;
 176         ENTRY;
 177
 178         LASSERT(cache);
 179
 180         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 181 find_again:
 182         found = 0;
 183         spin_lock(&cache->uc_lock);
 184         list_for_each_entry_safe(entry, next, head, ue_hash) {
 185                 /* check invalid & expired items */
 186                 if (check_unlink_entry(cache, entry))
 187                         continue;
 188                 if (upcall_compare(cache, entry, key, args) == 0) {
 189                         found = 1;
 190                         break;
 191                 }
 192         }
 193
 194         if (!found) { /* didn't find it */
 195                 if (!new) {
 196                         spin_unlock(&cache->uc_lock);
 197                         new = alloc_entry(cache, key, args);
 198                         if (!new) {
 199                                 CERROR("fail to alloc entry\n");
 200                                 RETURN(ERR_PTR(-ENOMEM));
 201                         }
 202                         goto find_again;
 203                 } else {
 204                         list_add(&new->ue_hash, head);
 205                         entry = new;
 206                 }
 207         } else {
 208                 if (new) {
 209                         free_entry(cache, new);
 210                         new = NULL;
 211                 }
 212                 list_move(&entry->ue_hash, head);
 213         }
 214         get_entry(entry);
 215
 216         /* acquire for new one */
 217         if (UC_CACHE_IS_NEW(entry)) {
 218                 UC_CACHE_SET_ACQUIRING(entry);
 219                 UC_CACHE_CLEAR_NEW(entry);
 220                 entry->ue_acquire_expire = jiffies + cache->uc_acquire_expire;
 221                 spin_unlock(&cache->uc_lock);
 222                 rc = refresh_entry(cache, entry);
 223                 spin_lock(&cache->uc_lock);
 224                 if (rc < 0) {
 225                         UC_CACHE_CLEAR_ACQUIRING(entry);
 226                         UC_CACHE_SET_INVALID(entry);
 227                         if (unlikely(rc == -EREMCHG)) {
 228                                 put_entry(cache, entry);
 229                                 GOTO(out, entry = ERR_PTR(rc));
 230                         }
 231                 }
 232                 /* fall through */
 233         }
 234         /* someone (and only one) is doing upcall upon
 235          * this item, just wait it complete
 236          */
 237         if (UC_CACHE_IS_ACQUIRING(entry)) {
 238                 unsigned long expiry = jiffies + cache->uc_acquire_expire;
 239
 240                 init_waitqueue_entry(&wait, current);
 241                 add_wait_queue(&entry->ue_waitq, &wait);
 242                 set_current_state(TASK_INTERRUPTIBLE);
 243                 spin_unlock(&cache->uc_lock);
 244
 245                 schedule_timeout(cache->uc_acquire_expire);
 246
 247                 spin_lock(&cache->uc_lock);
 248                 remove_wait_queue(&entry->ue_waitq, &wait);
 249                 if (UC_CACHE_IS_ACQUIRING(entry)) {
 250                         /* we're interrupted or upcall failed in the middle */
 251                         rc = time_before(jiffies, expiry) ? -EINTR : -ETIMEDOUT;
 252                         put_entry(cache, entry);
 253                         CERROR("acquire timeout exceeded for key "LPU64
 254                                "\n", entry->ue_key);
 255                         GOTO(out, entry = ERR_PTR(rc));
 256                 }
 257                 /* fall through */
 258         }
 259
 260         /* invalid means error, don't need to try again */
 261         if (UC_CACHE_IS_INVALID(entry)) {
 262                 put_entry(cache, entry);
 263                 GOTO(out, entry = ERR_PTR(-EIDRM));
 264         }
 265
 266         /* check expired
 267          * We can't refresh the existing one because some
 268          * memory might be shared by multiple processes.
 269          */
 270         if (check_unlink_entry(cache, entry)) {
 271                 /* if expired, try again. but if this entry is
 272                  * created by me but too quickly turn to expired
 273                  * without any error, should at least give a
 274                  * chance to use it once.
 275                  */
 276                 if (entry != new) {
 277                         put_entry(cache, entry);
 278                         spin_unlock(&cache->uc_lock);
 279                         new = NULL;
 280                         goto find_again;
 281                 }
 282         }
 283
 284         /* Now we know it's good */
 285 out:
 286         spin_unlock(&cache->uc_lock);
 287         RETURN(entry);
 288 }
 289 EXPORT_SYMBOL(upcall_cache_get_entry);
 290
 291 void upcall_cache_put_entry(struct upcall_cache *cache,
 292                             struct upcall_cache_entry *entry)
 293 {
 294         ENTRY;
 295
 296         if (!entry) {
 297                 EXIT;
 298                 return;
 299         }
 300
 301         LASSERT(atomic_read(&entry->ue_refcount) > 0);
 302         spin_lock(&cache->uc_lock);
 303         put_entry(cache, entry);
 304         spin_unlock(&cache->uc_lock);
 305         EXIT;
 306 }
 307 EXPORT_SYMBOL(upcall_cache_put_entry);
 308
 309 int upcall_cache_downcall(struct upcall_cache *cache, __u32 err, __u64 key,
 310                           void *args)
 311 {
 312         struct upcall_cache_entry *entry = NULL;
 313         struct list_head *head;
 314         int found = 0, rc = 0;
 315         ENTRY;
 316
 317         LASSERT(cache);
 318
 319         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 320
 321         spin_lock(&cache->uc_lock);
 322         list_for_each_entry(entry, head, ue_hash) {
 323                 if (downcall_compare(cache, entry, key, args) == 0) {
 324                         found = 1;
 325                         get_entry(entry);
 326                         break;
 327                 }
 328         }
 329
 330         if (!found) {
 331                 CDEBUG(D_OTHER, "%s: upcall for key "LPU64" not expected\n",
 332                        cache->uc_name, key);
 333                 /* haven't found, it's possible */
 334                 spin_unlock(&cache->uc_lock);
 335                 RETURN(-EINVAL);
 336         }
 337
 338         if (err) {
 339                 CDEBUG(D_OTHER, "%s: upcall for key "LPU64" returned %d\n",
 340                        cache->uc_name, entry->ue_key, err);
 341                 GOTO(out, rc = -EINVAL);
 342         }
 343
 344         if (!UC_CACHE_IS_ACQUIRING(entry)) {
 345                 CDEBUG(D_RPCTRACE,"%s: found uptodate entry %p (key "LPU64")\n",
 346                        cache->uc_name, entry, entry->ue_key);
 347                 GOTO(out, rc = 0);
 348         }
 349
 350         if (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry)) {
 351                 CERROR("%s: found a stale entry %p (key "LPU64") in ioctl\n",
 352                        cache->uc_name, entry, entry->ue_key);
 353                 GOTO(out, rc = -EINVAL);
 354         }
 355
 356         spin_unlock(&cache->uc_lock);
 357         if (cache->uc_ops->parse_downcall)
 358                 rc = cache->uc_ops->parse_downcall(cache, entry, args);
 359         spin_lock(&cache->uc_lock);
 360         if (rc)
 361                 GOTO(out, rc);
 362
 363         entry->ue_expire = jiffies + cache->uc_entry_expire;
 364         UC_CACHE_SET_VALID(entry);
 365         CDEBUG(D_OTHER, "%s: created upcall cache entry %p for key "LPU64"\n",
 366                cache->uc_name, entry, entry->ue_key);
 367 out:
 368         if (rc) {
 369                 UC_CACHE_SET_INVALID(entry);
 370                 list_del_init(&entry->ue_hash);
 371         }
 372         UC_CACHE_CLEAR_ACQUIRING(entry);
 373         spin_unlock(&cache->uc_lock);
 374         wake_up_all(&entry->ue_waitq);
 375         put_entry(cache, entry);
 376
 377         RETURN(rc);
 378 }
 379 EXPORT_SYMBOL(upcall_cache_downcall);
 380
 381 static void cache_flush(struct upcall_cache *cache, int force)
 382 {
 383         struct upcall_cache_entry *entry, *next;
 384         int i;
 385         ENTRY;
 386
 387         spin_lock(&cache->uc_lock);
 388         for (i = 0; i < UC_CACHE_HASH_SIZE; i++) {
 389                 list_for_each_entry_safe(entry, next,
 390                                          &cache->uc_hashtable[i], ue_hash) {
 391                         if (!force && atomic_read(&entry->ue_refcount)) {
 392                                 UC_CACHE_SET_EXPIRED(entry);
 393                                 continue;
 394                         }
 395                         LASSERT(!atomic_read(&entry->ue_refcount));
 396                         free_entry(cache, entry);
 397                 }
 398         }
 399         spin_unlock(&cache->uc_lock);
 400         EXIT;
 401 }
 402
 403 void upcall_cache_flush_idle(struct upcall_cache *cache)
 404 {
 405         cache_flush(cache, 0);
 406 }
 407 EXPORT_SYMBOL(upcall_cache_flush_idle);
 408
 409 void upcall_cache_flush_all(struct upcall_cache *cache)
 410 {
 411         cache_flush(cache, 1);
 412 }
 413 EXPORT_SYMBOL(upcall_cache_flush_all);
 414
 415 void upcall_cache_flush_one(struct upcall_cache *cache, __u64 key, void *args)
 416 {
 417         struct list_head *head;
 418         struct upcall_cache_entry *entry;
 419         int found = 0;
 420         ENTRY;
 421
 422         head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
 423
 424         spin_lock(&cache->uc_lock);
 425         list_for_each_entry(entry, head, ue_hash) {
 426                 if (upcall_compare(cache, entry, key, args) == 0) {
 427                         found = 1;
 428                         break;
 429                 }
 430         }
 431
 432         if (found) {
 433                 CWARN("%s: flush entry %p: key "LPU64", ref %d, fl %x, "
 434                       "cur %lu, ex %ld/%ld\n",
 435                       cache->uc_name, entry, entry->ue_key,
 436                       atomic_read(&entry->ue_refcount), entry->ue_flags,
 437                       get_seconds(), entry->ue_acquire_expire,
 438                       entry->ue_expire);
 439                 UC_CACHE_SET_EXPIRED(entry);
 440                 if (!atomic_read(&entry->ue_refcount))
 441                         free_entry(cache, entry);
 442         }
 443         spin_unlock(&cache->uc_lock);
 444 }
 445 EXPORT_SYMBOL(upcall_cache_flush_one);
 446
 447 struct upcall_cache *upcall_cache_init(const char *name, const char *upcall,
 448                                        struct upcall_cache_ops *ops)
 449 {
 450         struct upcall_cache *cache;
 451         int i;
 452         ENTRY;
 453
 454         OBD_ALLOC(cache, sizeof(*cache));
 455         if (!cache)
 456                 RETURN(ERR_PTR(-ENOMEM));
 457
 458         spin_lock_init(&cache->uc_lock);
 459         rwlock_init(&cache->uc_upcall_rwlock);
 460         for (i = 0; i < UC_CACHE_HASH_SIZE; i++)
 461                 INIT_LIST_HEAD(&cache->uc_hashtable[i]);
 462         strncpy(cache->uc_name, name, sizeof(cache->uc_name) - 1);
 463         /* upcall pathname proc tunable */
 464         strncpy(cache->uc_upcall, upcall, sizeof(cache->uc_upcall) - 1);
 465         cache->uc_entry_expire = 10 * 60 * HZ;
 466         cache->uc_acquire_expire = 15 * HZ;
 467         cache->uc_ops = ops;
 468
 469         RETURN(cache);
 470 }
 471 EXPORT_SYMBOL(upcall_cache_init);
 472
 473 void upcall_cache_cleanup(struct upcall_cache *cache)
 474 {
 475         if (!cache)
 476                 return;
 477         upcall_cache_flush_all(cache);
 478         OBD_FREE(cache, sizeof(*cache));
 479 }
 480 EXPORT_SYMBOL(upcall_cache_cleanup);