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