lustre/include/lustre_lmv.h

   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,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License version 2 for more details.  A copy is
  14  * included in the COPYING file that accompanied this code.
  15
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2014, 2016, Intel Corporation.
  24  */
  25 /*
  26  * lustre/include/lustre_lmv.h
  27  *
  28  * Lustre LMV structures and functions.
  29  *
  30  * Author: Di Wang <di.wang@intel.com>
  31  */
  32
  33 #ifndef _LUSTRE_LMV_H
  34 #define _LUSTRE_LMV_H
  35 #include <uapi/linux/lustre/lustre_idl.h>
  36
  37 struct lmv_oinfo {
  38         struct lu_fid   lmo_fid;
  39         u32             lmo_mds;
  40         struct inode    *lmo_root;
  41 };
  42
  43 struct lmv_stripe_md {
  44         __u32   lsm_md_magic;
  45         __u32   lsm_md_stripe_count;
  46         __u32   lsm_md_master_mdt_index;
  47         __u32   lsm_md_hash_type;
  48         __u8    lsm_md_max_inherit;
  49         __u8    lsm_md_max_inherit_rr;
  50         __u32   lsm_md_layout_version;
  51         __u32   lsm_md_migrate_offset;
  52         __u32   lsm_md_migrate_hash;
  53         __u32   lsm_md_default_count;
  54         __u32   lsm_md_default_index;
  55         char    lsm_md_pool_name[LOV_MAXPOOLNAME + 1];
  56         struct lmv_oinfo lsm_md_oinfo[0];
  57 };
  58
  59 static inline bool lmv_dir_striped(const struct lmv_stripe_md *lsm)
  60 {
  61         return lsm && lsm->lsm_md_magic == LMV_MAGIC;
  62 }
  63
  64 static inline bool lmv_dir_foreign(const struct lmv_stripe_md *lsm)
  65 {
  66         return lsm && lsm->lsm_md_magic == LMV_MAGIC_FOREIGN;
  67 }
  68
  69 static inline bool lmv_dir_layout_changing(const struct lmv_stripe_md *lsm)
  70 {
  71         return lmv_dir_striped(lsm) &&
  72                lmv_hash_is_layout_changing(lsm->lsm_md_hash_type);
  73 }
  74
  75 static inline bool lmv_dir_bad_hash(const struct lmv_stripe_md *lsm)
  76 {
  77         if (!lmv_dir_striped(lsm))
  78                 return false;
  79
  80         if (lsm->lsm_md_hash_type & LMV_HASH_FLAG_BAD_TYPE)
  81                 return true;
  82
  83         return !lmv_is_known_hash_type(lsm->lsm_md_hash_type);
  84 }
  85
  86 static inline bool
  87 lsm_md_eq(const struct lmv_stripe_md *lsm1, const struct lmv_stripe_md *lsm2)
  88 {
  89         __u32 idx;
  90
  91         if (lsm1->lsm_md_magic != lsm2->lsm_md_magic ||
  92             lsm1->lsm_md_stripe_count != lsm2->lsm_md_stripe_count ||
  93             lsm1->lsm_md_master_mdt_index !=
  94                                 lsm2->lsm_md_master_mdt_index ||
  95             lsm1->lsm_md_hash_type != lsm2->lsm_md_hash_type ||
  96             lsm1->lsm_md_layout_version !=
  97                                 lsm2->lsm_md_layout_version ||
  98             lsm1->lsm_md_migrate_offset !=
  99                                 lsm2->lsm_md_migrate_offset ||
 100             lsm1->lsm_md_migrate_hash !=
 101                                 lsm2->lsm_md_migrate_hash ||
 102             strncmp(lsm1->lsm_md_pool_name, lsm2->lsm_md_pool_name,
 103                     sizeof(lsm1->lsm_md_pool_name)) != 0)
 104                 return false;
 105
 106         if (lmv_dir_striped(lsm1)) {
 107                 for (idx = 0; idx < lsm1->lsm_md_stripe_count; idx++) {
 108                         if (!lu_fid_eq(&lsm1->lsm_md_oinfo[idx].lmo_fid,
 109                                        &lsm2->lsm_md_oinfo[idx].lmo_fid))
 110                                 return false;
 111                 }
 112         }
 113
 114         return true;
 115 }
 116
 117 static inline void lsm_md_dump(int mask, const struct lmv_stripe_md *lsm)
 118 {
 119         bool valid_hash = lmv_dir_bad_hash(lsm);
 120         int i;
 121
 122         /* If lsm_md_magic == LMV_MAGIC_FOREIGN pool_name may not be a null
 123          * terminated string so only print LOV_MAXPOOLNAME bytes.
 124          */
 125         CDEBUG(mask,
 126                "magic %#x stripe count %d master mdt %d hash type %s:%#x max inherit %hhu version %d migrate offset %d migrate hash %#x pool %.*s\n",
 127                lsm->lsm_md_magic, lsm->lsm_md_stripe_count,
 128                lsm->lsm_md_master_mdt_index,
 129                valid_hash ? "invalid hash" :
 130                             mdt_hash_name[lsm->lsm_md_hash_type & (LMV_HASH_TYPE_MAX - 1)],
 131                lsm->lsm_md_hash_type, lsm->lsm_md_max_inherit,
 132                lsm->lsm_md_layout_version,
 133                lsm->lsm_md_migrate_offset, lsm->lsm_md_migrate_hash,
 134                LOV_MAXPOOLNAME, lsm->lsm_md_pool_name);
 135
 136         if (!lmv_dir_striped(lsm))
 137                 return;
 138
 139         for (i = 0; i < lsm->lsm_md_stripe_count; i++)
 140                 CDEBUG(mask, "stripe[%d] "DFID"\n",
 141                        i, PFID(&lsm->lsm_md_oinfo[i].lmo_fid));
 142 }
 143
 144 union lmv_mds_md;
 145
 146 void lmv_free_memmd(struct lmv_stripe_md *lsm);
 147
 148 static inline void lmv1_le_to_cpu(struct lmv_mds_md_v1 *lmv_dst,
 149                                   const struct lmv_mds_md_v1 *lmv_src)
 150 {
 151         __u32 i;
 152
 153         lmv_dst->lmv_magic = le32_to_cpu(lmv_src->lmv_magic);
 154         lmv_dst->lmv_stripe_count = le32_to_cpu(lmv_src->lmv_stripe_count);
 155         lmv_dst->lmv_master_mdt_index =
 156                                 le32_to_cpu(lmv_src->lmv_master_mdt_index);
 157         lmv_dst->lmv_hash_type = le32_to_cpu(lmv_src->lmv_hash_type);
 158         lmv_dst->lmv_layout_version = le32_to_cpu(lmv_src->lmv_layout_version);
 159         if (lmv_src->lmv_stripe_count > LMV_MAX_STRIPE_COUNT)
 160                 return;
 161         for (i = 0; i < lmv_src->lmv_stripe_count; i++)
 162                 fid_le_to_cpu(&lmv_dst->lmv_stripe_fids[i],
 163                               &lmv_src->lmv_stripe_fids[i]);
 164 }
 165
 166 static inline void lmv_le_to_cpu(union lmv_mds_md *lmv_dst,
 167                                  const union lmv_mds_md *lmv_src)
 168 {
 169         switch (le32_to_cpu(lmv_src->lmv_magic)) {
 170         case LMV_MAGIC_V1:
 171                 lmv1_le_to_cpu(&lmv_dst->lmv_md_v1, &lmv_src->lmv_md_v1);
 172                 break;
 173         default:
 174                 break;
 175         }
 176 }
 177
 178 /* This hash is only for testing purpose */
 179 static inline unsigned int
 180 lmv_hash_all_chars(unsigned int count, const char *name, int namelen)
 181 {
 182         unsigned int c = 0;
 183         const unsigned char *p = (const unsigned char *)name;
 184
 185         while (--namelen >= 0)
 186                 c += p[namelen];
 187
 188         c = c % count;
 189
 190         return c;
 191 }
 192
 193 static inline unsigned int
 194 lmv_hash_fnv1a(unsigned int count, const char *name, int namelen)
 195 {
 196         __u64 hash;
 197
 198         hash = lustre_hash_fnv_1a_64(name, namelen);
 199
 200         return do_div(hash, count);
 201 }
 202
 203 /*
 204  * Robert Jenkins' function for mixing 32-bit values
 205  * http://burtleburtle.net/bob/hash/evahash.html
 206  * a, b = random bits, c = input and output
 207  *
 208  * Mixing inputs to generate an evenly distributed hash.
 209  */
 210 #define crush_hashmix(a, b, c)                          \
 211 do {                                                    \
 212         a = a - b;  a = a - c;  a = a ^ (c >> 13);      \
 213         b = b - c;  b = b - a;  b = b ^ (a << 8);       \
 214         c = c - a;  c = c - b;  c = c ^ (b >> 13);      \
 215         a = a - b;  a = a - c;  a = a ^ (c >> 12);      \
 216         b = b - c;  b = b - a;  b = b ^ (a << 16);      \
 217         c = c - a;  c = c - b;  c = c ^ (b >> 5);       \
 218         a = a - b;  a = a - c;  a = a ^ (c >> 3);       \
 219         b = b - c;  b = b - a;  b = b ^ (a << 10);      \
 220         c = c - a;  c = c - b;  c = c ^ (b >> 15);      \
 221 } while (0)
 222
 223 #define crush_hash_seed 1315423911
 224
 225 static inline __u32 crush_hash(__u32 a, __u32 b)
 226 {
 227         __u32 hash = crush_hash_seed ^ a ^ b;
 228         __u32 x = 231232;
 229         __u32 y = 1232;
 230
 231         crush_hashmix(a, b, hash);
 232         crush_hashmix(x, a, hash);
 233         crush_hashmix(b, y, hash);
 234
 235         return hash;
 236 }
 237
 238 /* refer to https://github.com/ceph/ceph/blob/master/src/crush/hash.c and
 239  * https://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf for details of CRUSH
 240  * algorithm.
 241  */
 242 static inline unsigned int
 243 lmv_hash_crush(unsigned int count, const char *name, int namelen)
 244 {
 245         unsigned long long straw;
 246         unsigned long long highest_straw = 0;
 247         unsigned int pg_id;
 248         unsigned int idx = 0;
 249         int i;
 250
 251         /* put temp and backup file on the same MDT where target is located.
 252          * temporary file naming rule:
 253          * 1. rsync: .<target>.XXXXXX
 254          * 2. dstripe: <target>.XXXXXXXX
 255          */
 256         if (lu_name_is_temp_file(name, namelen, true, 6)) {
 257                 name++;
 258                 namelen -= 8;
 259         } else if (lu_name_is_temp_file(name, namelen, false, 8)) {
 260                 namelen -= 9;
 261         } else if (lu_name_is_backup_file(name, namelen, &i)) {
 262                 LASSERT(i < namelen);
 263                 namelen -= i;
 264         }
 265
 266         pg_id = lmv_hash_fnv1a(LMV_CRUSH_PG_COUNT, name, namelen);
 267
 268         /* distribute PG among all stripes pseudo-randomly, so they are almost
 269          * evenly distributed, and when stripe count changes, only (delta /
 270          * total) sub files need to be moved, herein 'delta' is added or removed
 271          * stripe count, 'total' is total stripe count before change for
 272          * removal, or count after change for addition.
 273          */
 274         for (i = 0; i < count; i++) {
 275                 straw = crush_hash(pg_id, i);
 276                 if (straw > highest_straw) {
 277                         highest_straw = straw;
 278                         idx = i;
 279                 }
 280         }
 281         LASSERT(idx < count);
 282
 283         return idx;
 284 }
 285
 286 /* directory layout may change in three ways:
 287  * 1. directory migration, in its LMV source stripes are appended after
 288  *    target stripes, \a migrate_hash is source hash type, \a migrate_offset is
 289  *    target stripe count,
 290  * 2. directory split, \a migrate_hash is hash type before split,
 291  *    \a migrate_offset is stripe count before split.
 292  * 3. directory merge, \a migrate_hash is hash type after merge,
 293  *    \a migrate_offset is stripe count after merge.
 294  */
 295 static inline int
 296 __lmv_name_to_stripe_index(__u32 hash_type, __u32 stripe_count,
 297                            __u32 migrate_hash, __u32 migrate_offset,
 298                            const char *name, int namelen, bool new_layout)
 299 {
 300         __u32 saved_hash = hash_type;
 301         __u32 saved_count = stripe_count;
 302         int stripe_index = 0;
 303
 304         LASSERT(namelen > 0);
 305         LASSERT(stripe_count > 0);
 306
 307         if (lmv_hash_is_splitting(hash_type)) {
 308                 if (!new_layout) {
 309                         hash_type = migrate_hash;
 310                         stripe_count = migrate_offset;
 311                 }
 312         } else if (lmv_hash_is_merging(hash_type)) {
 313                 if (new_layout) {
 314                         hash_type = migrate_hash;
 315                         stripe_count = migrate_offset;
 316                 }
 317         } else if (lmv_hash_is_migrating(hash_type)) {
 318                 if (new_layout) {
 319                         stripe_count = migrate_offset;
 320                 } else {
 321                         hash_type = migrate_hash;
 322                         stripe_count -= migrate_offset;
 323                 }
 324         }
 325
 326         if (stripe_count > 1) {
 327                 switch (hash_type & LMV_HASH_TYPE_MASK) {
 328                 case LMV_HASH_TYPE_ALL_CHARS:
 329                         stripe_index = lmv_hash_all_chars(stripe_count, name,
 330                                                           namelen);
 331                         break;
 332                 case LMV_HASH_TYPE_FNV_1A_64:
 333                         stripe_index = lmv_hash_fnv1a(stripe_count, name,
 334                                                       namelen);
 335                         break;
 336                 case LMV_HASH_TYPE_CRUSH:
 337                         stripe_index = lmv_hash_crush(stripe_count, name,
 338                                                       namelen);
 339                         break;
 340                 default:
 341                         return -EBADFD;
 342                 }
 343         }
 344
 345         LASSERT(stripe_index < stripe_count);
 346
 347         if (!new_layout && lmv_hash_is_migrating(saved_hash))
 348                 stripe_index += migrate_offset;
 349
 350         LASSERT(stripe_index < saved_count);
 351
 352         CDEBUG(D_INFO, "name %.*s hash=%#x/%#x idx=%d/%u/%u under %s layout\n",
 353                namelen, name, saved_hash, migrate_hash, stripe_index,
 354                saved_count, migrate_offset, new_layout ? "new" : "old");
 355
 356         return stripe_index;
 357 }
 358
 359 static inline int lmv_name_to_stripe_index(struct lmv_mds_md_v1 *lmv,
 360                                            const char *name, int namelen)
 361 {
 362         if (lmv->lmv_magic == LMV_MAGIC_V1)
 363                 return __lmv_name_to_stripe_index(lmv->lmv_hash_type,
 364                                                   lmv->lmv_stripe_count,
 365                                                   lmv->lmv_migrate_hash,
 366                                                   lmv->lmv_migrate_offset,
 367                                                   name, namelen, true);
 368
 369         if (lmv->lmv_magic == cpu_to_le32(LMV_MAGIC_V1))
 370                 return __lmv_name_to_stripe_index(
 371                                         le32_to_cpu(lmv->lmv_hash_type),
 372                                         le32_to_cpu(lmv->lmv_stripe_count),
 373                                         le32_to_cpu(lmv->lmv_migrate_hash),
 374                                         le32_to_cpu(lmv->lmv_migrate_offset),
 375                                         name, namelen, true);
 376
 377         return -EINVAL;
 378 }
 379
 380 static inline int lmv_name_to_stripe_index_old(struct lmv_mds_md_v1 *lmv,
 381                                                const char *name, int namelen)
 382 {
 383         if (lmv->lmv_magic == LMV_MAGIC_V1 ||
 384             lmv->lmv_magic == LMV_MAGIC_STRIPE)
 385                 return __lmv_name_to_stripe_index(lmv->lmv_hash_type,
 386                                                   lmv->lmv_stripe_count,
 387                                                   lmv->lmv_migrate_hash,
 388                                                   lmv->lmv_migrate_offset,
 389                                                   name, namelen, false);
 390
 391         if (lmv->lmv_magic == cpu_to_le32(LMV_MAGIC_V1) ||
 392             lmv->lmv_magic == cpu_to_le32(LMV_MAGIC_STRIPE))
 393                 return __lmv_name_to_stripe_index(
 394                                         le32_to_cpu(lmv->lmv_hash_type),
 395                                         le32_to_cpu(lmv->lmv_stripe_count),
 396                                         le32_to_cpu(lmv->lmv_migrate_hash),
 397                                         le32_to_cpu(lmv->lmv_migrate_offset),
 398                                         name, namelen, false);
 399
 400         return -EINVAL;
 401 }
 402
 403 static inline bool lmv_user_magic_supported(__u32 lum_magic)
 404 {
 405         return lum_magic == LMV_USER_MAGIC ||
 406                lum_magic == LMV_USER_MAGIC_SPECIFIC ||
 407                lum_magic == LMV_MAGIC_FOREIGN;
 408 }
 409
 410 #define LMV_DEBUG(mask, lmv, msg)                                       \
 411         CDEBUG(mask,                                                    \
 412                "%s LMV: magic=%#x count=%u index=%u hash=%s:%#x version=%u migrate offset=%u migrate hash=%s:%u.\n",\
 413                msg, (lmv)->lmv_magic, (lmv)->lmv_stripe_count,          \
 414                (lmv)->lmv_master_mdt_index,                             \
 415                mdt_hash_name[(lmv)->lmv_hash_type & (LMV_HASH_TYPE_MAX - 1)],\
 416                (lmv)->lmv_hash_type, (lmv)->lmv_layout_version,         \
 417                (lmv)->lmv_migrate_offset,                               \
 418                mdt_hash_name[(lmv)->lmv_migrate_hash & (LMV_HASH_TYPE_MAX - 1)],\
 419                (lmv)->lmv_migrate_hash)
 420
 421 /* master LMV is sane */
 422 static inline bool lmv_is_sane(const struct lmv_mds_md_v1 *lmv)
 423 {
 424         if (!lmv)
 425                 return false;
 426
 427         if (le32_to_cpu(lmv->lmv_magic) != LMV_MAGIC_V1)
 428                 goto insane;
 429
 430         if (le32_to_cpu(lmv->lmv_stripe_count) == 0)
 431                 goto insane;
 432
 433         if (!lmv_is_known_hash_type(le32_to_cpu(lmv->lmv_hash_type)))
 434                 goto insane;
 435
 436         return true;
 437 insane:
 438         LMV_DEBUG(D_ERROR, lmv, "insane");
 439         return false;
 440 }
 441
 442 /* LMV can be either master or stripe LMV */
 443 static inline bool lmv_is_sane2(const struct lmv_mds_md_v1 *lmv)
 444 {
 445         if (!lmv)
 446                 return false;
 447
 448         if (le32_to_cpu(lmv->lmv_magic) != LMV_MAGIC_V1 &&
 449             le32_to_cpu(lmv->lmv_magic) != LMV_MAGIC_STRIPE)
 450                 goto insane;
 451
 452         if (le32_to_cpu(lmv->lmv_stripe_count) == 0)
 453                 goto insane;
 454
 455         if (!lmv_is_known_hash_type(le32_to_cpu(lmv->lmv_hash_type)))
 456                 goto insane;
 457
 458         return true;
 459 insane:
 460         LMV_DEBUG(D_ERROR, lmv, "insane");
 461         return false;
 462 }
 463
 464 static inline bool lmv_is_splitting(const struct lmv_mds_md_v1 *lmv)
 465 {
 466         if (!lmv_is_sane2(lmv))
 467                 return false;
 468
 469         return lmv_hash_is_splitting(cpu_to_le32(lmv->lmv_hash_type));
 470 }
 471
 472 static inline bool lmv_is_merging(const struct lmv_mds_md_v1 *lmv)
 473 {
 474         if (!lmv_is_sane2(lmv))
 475                 return false;
 476
 477         return lmv_hash_is_merging(cpu_to_le32(lmv->lmv_hash_type));
 478 }
 479
 480 static inline bool lmv_is_migrating(const struct lmv_mds_md_v1 *lmv)
 481 {
 482         if (!lmv_is_sane(lmv))
 483                 return false;
 484
 485         return lmv_hash_is_migrating(cpu_to_le32(lmv->lmv_hash_type));
 486 }
 487
 488 static inline bool lmv_is_restriping(const struct lmv_mds_md_v1 *lmv)
 489 {
 490         if (!lmv_is_sane2(lmv))
 491                 return false;
 492
 493         return lmv_hash_is_splitting(cpu_to_le32(lmv->lmv_hash_type)) ||
 494                lmv_hash_is_merging(cpu_to_le32(lmv->lmv_hash_type));
 495 }
 496
 497 static inline bool lmv_is_layout_changing(const struct lmv_mds_md_v1 *lmv)
 498 {
 499         if (!lmv_is_sane2(lmv))
 500                 return false;
 501
 502         return lmv_hash_is_splitting(cpu_to_le32(lmv->lmv_hash_type)) ||
 503                lmv_hash_is_merging(cpu_to_le32(lmv->lmv_hash_type)) ||
 504                lmv_hash_is_migrating(cpu_to_le32(lmv->lmv_hash_type));
 505 }
 506
 507 static inline bool lmv_is_fixed(const struct lmv_mds_md_v1 *lmv)
 508 {
 509         return cpu_to_le32(lmv->lmv_hash_type) & LMV_HASH_FLAG_FIXED;
 510 }
 511
 512 #endif