lustre/fld/fld_cache.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2012, 2014, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * lustre/fld/fld_cache.c
  33  *
  34  * FLD (Fids Location Database)
  35  *
  36  * Author: Pravin Shelar <pravin.shelar@sun.com>
  37  * Author: Yury Umanets <umka@clusterfs.com>
  38  */
  39
  40 #define DEBUG_SUBSYSTEM S_FLD
  41
  42 #include <libcfs/libcfs.h>
  43 #include <linux/module.h>
  44 #include <linux/math64.h>
  45 #include <obd_support.h>
  46 #include <lustre_fld.h>
  47 #include "fld_internal.h"
  48
  49 /**
  50  * create fld cache.
  51  */
  52 struct fld_cache *fld_cache_init(const char *name,
  53                                  int cache_size, int cache_threshold)
  54 {
  55         struct fld_cache *cache;
  56         ENTRY;
  57
  58         LASSERT(name != NULL);
  59         LASSERT(cache_threshold < cache_size);
  60
  61         OBD_ALLOC_PTR(cache);
  62         if (cache == NULL)
  63                 RETURN(ERR_PTR(-ENOMEM));
  64
  65         INIT_LIST_HEAD(&cache->fci_entries_head);
  66         INIT_LIST_HEAD(&cache->fci_lru);
  67
  68         cache->fci_cache_count = 0;
  69         rwlock_init(&cache->fci_lock);
  70
  71         strlcpy(cache->fci_name, name,
  72                 sizeof(cache->fci_name));
  73
  74         cache->fci_cache_size = cache_size;
  75         cache->fci_threshold = cache_threshold;
  76
  77         /* Init fld cache info. */
  78         memset(&cache->fci_stat, 0, sizeof(cache->fci_stat));
  79
  80         CDEBUG(D_INFO, "%s: FLD cache - Size: %d, Threshold: %d\n",
  81                cache->fci_name, cache_size, cache_threshold);
  82
  83         RETURN(cache);
  84 }
  85
  86 /**
  87  * destroy fld cache.
  88  */
  89 void fld_cache_fini(struct fld_cache *cache)
  90 {
  91         LASSERT(cache != NULL);
  92         fld_cache_flush(cache);
  93
  94         CDEBUG(D_INFO, "FLD cache statistics (%s):\n", cache->fci_name);
  95         CDEBUG(D_INFO, "  Cache reqs: %llu\n", cache->fci_stat.fst_cache);
  96         CDEBUG(D_INFO, "  Total reqs: %llu\n", cache->fci_stat.fst_count);
  97
  98         OBD_FREE_PTR(cache);
  99 }
 100
 101 /**
 102  * delete given node from list.
 103  */
 104 void fld_cache_entry_delete(struct fld_cache *cache,
 105                             struct fld_cache_entry *node)
 106 {
 107         list_del(&node->fce_list);
 108         list_del(&node->fce_lru);
 109         cache->fci_cache_count--;
 110         OBD_FREE_PTR(node);
 111 }
 112
 113 /**
 114  * fix list by checking new entry with NEXT entry in order.
 115  */
 116 static void fld_fix_new_list(struct fld_cache *cache)
 117 {
 118         struct fld_cache_entry *f_curr;
 119         struct fld_cache_entry *f_next;
 120         struct lu_seq_range *c_range;
 121         struct lu_seq_range *n_range;
 122         struct list_head *head = &cache->fci_entries_head;
 123         ENTRY;
 124
 125 restart_fixup:
 126
 127         list_for_each_entry_safe(f_curr, f_next, head, fce_list) {
 128                 c_range = &f_curr->fce_range;
 129                 n_range = &f_next->fce_range;
 130
 131                 LASSERT(lu_seq_range_is_sane(c_range));
 132                 if (&f_next->fce_list == head)
 133                         break;
 134
 135                 if (c_range->lsr_flags != n_range->lsr_flags)
 136                         continue;
 137
 138                 LASSERTF(c_range->lsr_start <= n_range->lsr_start,
 139                          "cur lsr_start "DRANGE" next lsr_start "DRANGE"\n",
 140                          PRANGE(c_range), PRANGE(n_range));
 141
 142                 /* check merge possibility with next range */
 143                 if (c_range->lsr_end == n_range->lsr_start) {
 144                         if (c_range->lsr_index != n_range->lsr_index)
 145                                 continue;
 146                         n_range->lsr_start = c_range->lsr_start;
 147                         fld_cache_entry_delete(cache, f_curr);
 148                         continue;
 149                 }
 150
 151                 /* check if current range overlaps with next range. */
 152                 if (n_range->lsr_start < c_range->lsr_end) {
 153                         if (c_range->lsr_index == n_range->lsr_index) {
 154                                 n_range->lsr_start = c_range->lsr_start;
 155                                 n_range->lsr_end = max(c_range->lsr_end,
 156                                                        n_range->lsr_end);
 157                                 fld_cache_entry_delete(cache, f_curr);
 158                         } else {
 159                                 if (n_range->lsr_end <= c_range->lsr_end) {
 160                                         *n_range = *c_range;
 161                                         fld_cache_entry_delete(cache, f_curr);
 162                                 } else
 163                                         n_range->lsr_start = c_range->lsr_end;
 164                         }
 165
 166                         /* we could have overlap over next
 167                          * range too. better restart. */
 168                         goto restart_fixup;
 169                 }
 170
 171                 /* kill duplicates */
 172                 if (c_range->lsr_start == n_range->lsr_start &&
 173                     c_range->lsr_end == n_range->lsr_end)
 174                         fld_cache_entry_delete(cache, f_curr);
 175         }
 176
 177         EXIT;
 178 }
 179
 180 /**
 181  * add node to fld cache
 182  */
 183 static inline void fld_cache_entry_add(struct fld_cache *cache,
 184                                        struct fld_cache_entry *f_new,
 185                                        struct list_head *pos)
 186 {
 187         list_add(&f_new->fce_list, pos);
 188         list_add(&f_new->fce_lru, &cache->fci_lru);
 189
 190         cache->fci_cache_count++;
 191         fld_fix_new_list(cache);
 192 }
 193
 194 /**
 195  * Check if cache needs to be shrunk. If so - do it.
 196  * Remove one entry in list and so on until cache is shrunk enough.
 197  */
 198 static int fld_cache_shrink(struct fld_cache *cache)
 199 {
 200         struct fld_cache_entry *flde;
 201         struct list_head *curr;
 202         int num = 0;
 203         ENTRY;
 204
 205         LASSERT(cache != NULL);
 206
 207         if (cache->fci_cache_count < cache->fci_cache_size)
 208                 RETURN(0);
 209
 210         curr = cache->fci_lru.prev;
 211
 212         while (cache->fci_cache_count + cache->fci_threshold >
 213                cache->fci_cache_size && curr != &cache->fci_lru) {
 214
 215                 flde = list_entry(curr, struct fld_cache_entry, fce_lru);
 216                 curr = curr->prev;
 217                 fld_cache_entry_delete(cache, flde);
 218                 num++;
 219         }
 220
 221         CDEBUG(D_INFO, "%s: FLD cache - Shrunk by "
 222                "%d entries\n", cache->fci_name, num);
 223
 224         RETURN(0);
 225 }
 226
 227 /**
 228  * kill all fld cache entries.
 229  */
 230 void fld_cache_flush(struct fld_cache *cache)
 231 {
 232         ENTRY;
 233
 234         write_lock(&cache->fci_lock);
 235         cache->fci_cache_size = 0;
 236         fld_cache_shrink(cache);
 237         write_unlock(&cache->fci_lock);
 238
 239         EXIT;
 240 }
 241
 242 /**
 243  * punch hole in existing range. divide this range and add new
 244  * entry accordingly.
 245  */
 246
 247 static void fld_cache_punch_hole(struct fld_cache *cache,
 248                                  struct fld_cache_entry *f_curr,
 249                                  struct fld_cache_entry *f_new)
 250 {
 251         const struct lu_seq_range *range = &f_new->fce_range;
 252         const u64 new_start  = range->lsr_start;
 253         const u64 new_end  = range->lsr_end;
 254         struct fld_cache_entry *fldt;
 255
 256         ENTRY;
 257         OBD_ALLOC_GFP(fldt, sizeof *fldt, GFP_ATOMIC);
 258         if (!fldt) {
 259                 OBD_FREE_PTR(f_new);
 260                 EXIT;
 261                 /* overlap is not allowed, so dont mess up list. */
 262                 return;
 263         }
 264         /*  break f_curr RANGE into three RANGES:
 265          *        f_curr, f_new , fldt
 266          */
 267
 268         /* f_new = *range */
 269
 270         /* fldt */
 271         fldt->fce_range.lsr_start = new_end;
 272         fldt->fce_range.lsr_end = f_curr->fce_range.lsr_end;
 273         fldt->fce_range.lsr_index = f_curr->fce_range.lsr_index;
 274
 275         /* f_curr */
 276         f_curr->fce_range.lsr_end = new_start;
 277
 278         /* add these two entries to list */
 279         fld_cache_entry_add(cache, f_new, &f_curr->fce_list);
 280         fld_cache_entry_add(cache, fldt, &f_new->fce_list);
 281
 282         /* no need to fixup */
 283         EXIT;
 284 }
 285
 286 /**
 287  * handle range overlap in fld cache.
 288  */
 289 static void fld_cache_overlap_handle(struct fld_cache *cache,
 290                                 struct fld_cache_entry *f_curr,
 291                                 struct fld_cache_entry *f_new)
 292 {
 293         const struct lu_seq_range *range = &f_new->fce_range;
 294         const u64 new_start  = range->lsr_start;
 295         const u64 new_end  = range->lsr_end;
 296         const u32 mdt = range->lsr_index;
 297
 298         /* this is overlap case, these case are checking overlapping with
 299          * prev range only. fixup will handle overlaping with next range. */
 300
 301         if (f_curr->fce_range.lsr_index == mdt) {
 302                 f_curr->fce_range.lsr_start = min(f_curr->fce_range.lsr_start,
 303                                                   new_start);
 304
 305                 f_curr->fce_range.lsr_end = max(f_curr->fce_range.lsr_end,
 306                                                 new_end);
 307
 308                 OBD_FREE_PTR(f_new);
 309                 fld_fix_new_list(cache);
 310
 311         } else if (new_start <= f_curr->fce_range.lsr_start &&
 312                         f_curr->fce_range.lsr_end <= new_end) {
 313                 /* case 1: new range completely overshadowed existing range.
 314                  *         e.g. whole range migrated. update fld cache entry */
 315
 316                 f_curr->fce_range = *range;
 317                 OBD_FREE_PTR(f_new);
 318                 fld_fix_new_list(cache);
 319
 320         } else if (f_curr->fce_range.lsr_start < new_start &&
 321                         new_end < f_curr->fce_range.lsr_end) {
 322                 /* case 2: new range fit within existing range. */
 323
 324                 fld_cache_punch_hole(cache, f_curr, f_new);
 325
 326         } else  if (new_end <= f_curr->fce_range.lsr_end) {
 327                 /* case 3: overlap:
 328                  *         [new_start [c_start  new_end)  c_end)
 329                  */
 330
 331                 LASSERT(new_start <= f_curr->fce_range.lsr_start);
 332
 333                 f_curr->fce_range.lsr_start = new_end;
 334                 fld_cache_entry_add(cache, f_new, f_curr->fce_list.prev);
 335
 336         } else if (f_curr->fce_range.lsr_start <= new_start) {
 337                 /* case 4: overlap:
 338                  *         [c_start [new_start c_end) new_end)
 339                  */
 340
 341                 LASSERT(f_curr->fce_range.lsr_end <= new_end);
 342
 343                 f_curr->fce_range.lsr_end = new_start;
 344                 fld_cache_entry_add(cache, f_new, &f_curr->fce_list);
 345         } else
 346                 CERROR("NEW range ="DRANGE" curr = "DRANGE"\n",
 347                        PRANGE(range),PRANGE(&f_curr->fce_range));
 348 }
 349
 350 struct fld_cache_entry
 351 *fld_cache_entry_create(const struct lu_seq_range *range)
 352 {
 353         struct fld_cache_entry *f_new;
 354
 355         LASSERT(lu_seq_range_is_sane(range));
 356
 357         OBD_ALLOC_PTR(f_new);
 358         if (!f_new)
 359                 RETURN(ERR_PTR(-ENOMEM));
 360
 361         f_new->fce_range = *range;
 362         RETURN(f_new);
 363 }
 364
 365 /**
 366  * Insert FLD entry in FLD cache.
 367  *
 368  * This function handles all cases of merging and breaking up of
 369  * ranges.
 370  */
 371 int fld_cache_insert_nolock(struct fld_cache *cache,
 372                             struct fld_cache_entry *f_new)
 373 {
 374         struct fld_cache_entry *f_curr;
 375         struct fld_cache_entry *n;
 376         struct list_head *head;
 377         struct list_head *prev = NULL;
 378         const u64 new_start  = f_new->fce_range.lsr_start;
 379         const u64 new_end  = f_new->fce_range.lsr_end;
 380         __u32 new_flags  = f_new->fce_range.lsr_flags;
 381         ENTRY;
 382
 383         /*
 384          * Duplicate entries are eliminated in insert op.
 385          * So we don't need to search new entry before starting
 386          * insertion loop.
 387          */
 388
 389         fld_cache_shrink(cache);
 390
 391         head = &cache->fci_entries_head;
 392
 393         list_for_each_entry_safe(f_curr, n, head, fce_list) {
 394                 /* add list if next is end of list */
 395                 if (new_end < f_curr->fce_range.lsr_start ||
 396                    (new_end == f_curr->fce_range.lsr_start &&
 397                     new_flags != f_curr->fce_range.lsr_flags))
 398                         break;
 399
 400                 prev = &f_curr->fce_list;
 401                 /* check if this range is to left of new range. */
 402                 if (new_start < f_curr->fce_range.lsr_end &&
 403                     new_flags == f_curr->fce_range.lsr_flags) {
 404                         fld_cache_overlap_handle(cache, f_curr, f_new);
 405                         goto out;
 406                 }
 407         }
 408
 409         if (prev == NULL)
 410                 prev = head;
 411
 412         CDEBUG(D_INFO, "insert range "DRANGE"\n", PRANGE(&f_new->fce_range));
 413         /* Add new entry to cache and lru list. */
 414         fld_cache_entry_add(cache, f_new, prev);
 415 out:
 416         RETURN(0);
 417 }
 418
 419 int fld_cache_insert(struct fld_cache *cache,
 420                      const struct lu_seq_range *range)
 421 {
 422         struct fld_cache_entry  *flde;
 423         int rc;
 424
 425         flde = fld_cache_entry_create(range);
 426         if (IS_ERR(flde))
 427                 RETURN(PTR_ERR(flde));
 428
 429         write_lock(&cache->fci_lock);
 430         rc = fld_cache_insert_nolock(cache, flde);
 431         write_unlock(&cache->fci_lock);
 432         if (rc)
 433                 OBD_FREE_PTR(flde);
 434
 435         RETURN(rc);
 436 }
 437
 438 void fld_cache_delete_nolock(struct fld_cache *cache,
 439                       const struct lu_seq_range *range)
 440 {
 441         struct fld_cache_entry *flde;
 442         struct fld_cache_entry *tmp;
 443         struct list_head *head;
 444
 445         head = &cache->fci_entries_head;
 446         list_for_each_entry_safe(flde, tmp, head, fce_list) {
 447                 /* add list if next is end of list */
 448                 if (range->lsr_start == flde->fce_range.lsr_start ||
 449                    (range->lsr_end == flde->fce_range.lsr_end &&
 450                     range->lsr_flags == flde->fce_range.lsr_flags)) {
 451                         fld_cache_entry_delete(cache, flde);
 452                         break;
 453                 }
 454         }
 455 }
 456
 457 /**
 458  * Delete FLD entry in FLD cache.
 459  *
 460  */
 461 void fld_cache_delete(struct fld_cache *cache,
 462                       const struct lu_seq_range *range)
 463 {
 464         write_lock(&cache->fci_lock);
 465         fld_cache_delete_nolock(cache, range);
 466         write_unlock(&cache->fci_lock);
 467 }
 468
 469 struct fld_cache_entry *
 470 fld_cache_entry_lookup_nolock(struct fld_cache *cache,
 471                               const struct lu_seq_range *range)
 472 {
 473         struct fld_cache_entry *flde;
 474         struct fld_cache_entry *got = NULL;
 475         struct list_head *head;
 476
 477         head = &cache->fci_entries_head;
 478         list_for_each_entry(flde, head, fce_list) {
 479                 if (range->lsr_start == flde->fce_range.lsr_start ||
 480                    (range->lsr_end == flde->fce_range.lsr_end &&
 481                     range->lsr_flags == flde->fce_range.lsr_flags)) {
 482                         got = flde;
 483                         break;
 484                 }
 485         }
 486
 487         RETURN(got);
 488 }
 489
 490 /**
 491  * lookup \a seq sequence for range in fld cache.
 492  */
 493 struct fld_cache_entry *
 494 fld_cache_entry_lookup(struct fld_cache *cache,
 495                        const struct lu_seq_range *range)
 496 {
 497         struct fld_cache_entry *got = NULL;
 498         ENTRY;
 499
 500         read_lock(&cache->fci_lock);
 501         got = fld_cache_entry_lookup_nolock(cache, range);
 502         read_unlock(&cache->fci_lock);
 503
 504         RETURN(got);
 505 }
 506
 507 /**
 508  * lookup \a seq sequence for range in fld cache.
 509  */
 510 int fld_cache_lookup(struct fld_cache *cache,
 511                      const u64 seq, struct lu_seq_range *range)
 512 {
 513         struct fld_cache_entry *flde;
 514         struct fld_cache_entry *prev = NULL;
 515         struct list_head *head;
 516         ENTRY;
 517
 518         read_lock(&cache->fci_lock);
 519         head = &cache->fci_entries_head;
 520
 521         cache->fci_stat.fst_count++;
 522         list_for_each_entry(flde, head, fce_list) {
 523                 if (flde->fce_range.lsr_start > seq) {
 524                         if (prev != NULL)
 525                                 *range = prev->fce_range;
 526                         break;
 527                 }
 528
 529                 prev = flde;
 530                 if (lu_seq_range_within(&flde->fce_range, seq)) {
 531                         *range = flde->fce_range;
 532
 533                         cache->fci_stat.fst_cache++;
 534                         read_unlock(&cache->fci_lock);
 535                         RETURN(0);
 536                 }
 537         }
 538         read_unlock(&cache->fci_lock);
 539         RETURN(-ENOENT);
 540 }