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         int i;
 120
 121         /* If lsm_md_magic == LMV_MAGIC_FOREIGN pool_name may not be a null
 122          * terminated string so only print LOV_MAXPOOLNAME bytes.
 123          */
 124         CDEBUG(mask,
 125                "magic %#x stripe count %d master mdt %d hash type %#x max inherit %hhu version %d migrate offset %d migrate hash %#x pool %.*s\n",
 126                lsm->lsm_md_magic, lsm->lsm_md_stripe_count,
 127                lsm->lsm_md_master_mdt_index, lsm->lsm_md_hash_type,
 128                lsm->lsm_md_max_inherit, lsm->lsm_md_layout_version,
 129                lsm->lsm_md_migrate_offset, lsm->lsm_md_migrate_hash,
 130                LOV_MAXPOOLNAME, lsm->lsm_md_pool_name);
 131
 132         if (!lmv_dir_striped(lsm))
 133                 return;
 134
 135         for (i = 0; i < lsm->lsm_md_stripe_count; i++)
 136                 CDEBUG(mask, "stripe[%d] "DFID"\n",
 137                        i, PFID(&lsm->lsm_md_oinfo[i].lmo_fid));
 138 }
 139
 140 union lmv_mds_md;
 141
 142 void lmv_free_memmd(struct lmv_stripe_md *lsm);
 143
 144 static inline void lmv1_le_to_cpu(struct lmv_mds_md_v1 *lmv_dst,
 145                                   const struct lmv_mds_md_v1 *lmv_src)
 146 {
 147         __u32 i;
 148
 149         lmv_dst->lmv_magic = le32_to_cpu(lmv_src->lmv_magic);
 150         lmv_dst->lmv_stripe_count = le32_to_cpu(lmv_src->lmv_stripe_count);
 151         lmv_dst->lmv_master_mdt_index =
 152                                 le32_to_cpu(lmv_src->lmv_master_mdt_index);
 153         lmv_dst->lmv_hash_type = le32_to_cpu(lmv_src->lmv_hash_type);
 154         lmv_dst->lmv_layout_version = le32_to_cpu(lmv_src->lmv_layout_version);
 155         if (lmv_src->lmv_stripe_count > LMV_MAX_STRIPE_COUNT)
 156                 return;
 157         for (i = 0; i < lmv_src->lmv_stripe_count; i++)
 158                 fid_le_to_cpu(&lmv_dst->lmv_stripe_fids[i],
 159                               &lmv_src->lmv_stripe_fids[i]);
 160 }
 161
 162 static inline void lmv_le_to_cpu(union lmv_mds_md *lmv_dst,
 163                                  const union lmv_mds_md *lmv_src)
 164 {
 165         switch (le32_to_cpu(lmv_src->lmv_magic)) {
 166         case LMV_MAGIC_V1:
 167                 lmv1_le_to_cpu(&lmv_dst->lmv_md_v1, &lmv_src->lmv_md_v1);
 168                 break;
 169         default:
 170                 break;
 171         }
 172 }
 173
 174 /* This hash is only for testing purpose */
 175 static inline unsigned int
 176 lmv_hash_all_chars(unsigned int count, const char *name, int namelen)
 177 {
 178         unsigned int c = 0;
 179         const unsigned char *p = (const unsigned char *)name;
 180
 181         while (--namelen >= 0)
 182                 c += p[namelen];
 183
 184         c = c % count;
 185
 186         return c;
 187 }
 188
 189 static inline unsigned int
 190 lmv_hash_fnv1a(unsigned int count, const char *name, int namelen)
 191 {
 192         __u64 hash;
 193
 194         hash = lustre_hash_fnv_1a_64(name, namelen);
 195
 196         return do_div(hash, count);
 197 }
 198
 199 /*
 200  * Robert Jenkins' function for mixing 32-bit values
 201  * http://burtleburtle.net/bob/hash/evahash.html
 202  * a, b = random bits, c = input and output
 203  *
 204  * Mixing inputs to generate an evenly distributed hash.
 205  */
 206 #define crush_hashmix(a, b, c)                          \
 207 do {                                                    \
 208         a = a - b;  a = a - c;  a = a ^ (c >> 13);      \
 209         b = b - c;  b = b - a;  b = b ^ (a << 8);       \
 210         c = c - a;  c = c - b;  c = c ^ (b >> 13);      \
 211         a = a - b;  a = a - c;  a = a ^ (c >> 12);      \
 212         b = b - c;  b = b - a;  b = b ^ (a << 16);      \
 213         c = c - a;  c = c - b;  c = c ^ (b >> 5);       \
 214         a = a - b;  a = a - c;  a = a ^ (c >> 3);       \
 215         b = b - c;  b = b - a;  b = b ^ (a << 10);      \
 216         c = c - a;  c = c - b;  c = c ^ (b >> 15);      \
 217 } while (0)
 218
 219 #define crush_hash_seed 1315423911
 220
 221 static inline __u32 crush_hash(__u32 a, __u32 b)
 222 {
 223         __u32 hash = crush_hash_seed ^ a ^ b;
 224         __u32 x = 231232;
 225         __u32 y = 1232;
 226
 227         crush_hashmix(a, b, hash);
 228         crush_hashmix(x, a, hash);
 229         crush_hashmix(b, y, hash);
 230
 231         return hash;
 232 }
 233
 234 /* refer to https://github.com/ceph/ceph/blob/master/src/crush/hash.c and
 235  * https://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf for details of CRUSH
 236  * algorithm.
 237  */
 238 static inline unsigned int
 239 lmv_hash_crush(unsigned int count, const char *name, int namelen)
 240 {
 241         unsigned long long straw;
 242         unsigned long long highest_straw = 0;
 243         unsigned int pg_id;
 244         unsigned int idx = 0;
 245         int i;
 246
 247         /* put temp and backup file on the same MDT where target is located.
 248          * temporary file naming rule:
 249          * 1. rsync: .<target>.XXXXXX
 250          * 2. dstripe: <target>.XXXXXXXX
 251          */
 252         if (lu_name_is_temp_file(name, namelen, true, 6)) {
 253                 name++;
 254                 namelen -= 8;
 255         } else if (lu_name_is_temp_file(name, namelen, false, 8)) {
 256                 namelen -= 9;
 257         } else if (lu_name_is_backup_file(name, namelen, &i)) {
 258                 LASSERT(i < namelen);
 259                 namelen -= i;
 260         }
 261
 262         pg_id = lmv_hash_fnv1a(LMV_CRUSH_PG_COUNT, name, namelen);
 263
 264         /* distribute PG among all stripes pseudo-randomly, so they are almost
 265          * evenly distributed, and when stripe count changes, only (delta /
 266          * total) sub files need to be moved, herein 'delta' is added or removed
 267          * stripe count, 'total' is total stripe count before change for
 268          * removal, or count after change for addition.
 269          */
 270         for (i = 0; i < count; i++) {
 271                 straw = crush_hash(pg_id, i);
 272                 if (straw > highest_straw) {
 273                         highest_straw = straw;
 274                         idx = i;
 275                 }
 276         }
 277         LASSERT(idx < count);
 278
 279         return idx;
 280 }
 281
 282 /* directory layout may change in three ways:
 283  * 1. directory migration, in its LMV source stripes are appended after
 284  *    target stripes, \a migrate_hash is source hash type, \a migrate_offset is
 285  *    target stripe count,
 286  * 2. directory split, \a migrate_hash is hash type before split,
 287  *    \a migrate_offset is stripe count before split.
 288  * 3. directory merge, \a migrate_hash is hash type after merge,
 289  *    \a migrate_offset is stripe count after merge.
 290  */
 291 static inline int
 292 __lmv_name_to_stripe_index(__u32 hash_type, __u32 stripe_count,
 293                            __u32 migrate_hash, __u32 migrate_offset,
 294                            const char *name, int namelen, bool new_layout)
 295 {
 296         __u32 saved_hash = hash_type;
 297         __u32 saved_count = stripe_count;
 298         int stripe_index = 0;
 299
 300         LASSERT(namelen > 0);
 301         LASSERT(stripe_count > 0);
 302
 303         if (lmv_hash_is_splitting(hash_type)) {
 304                 if (!new_layout) {
 305                         hash_type = migrate_hash;
 306                         stripe_count = migrate_offset;
 307                 }
 308         } else if (lmv_hash_is_merging(hash_type)) {
 309                 if (new_layout) {
 310                         hash_type = migrate_hash;
 311                         stripe_count = migrate_offset;
 312                 }
 313         } else if (lmv_hash_is_migrating(hash_type)) {
 314                 if (new_layout) {
 315                         stripe_count = migrate_offset;
 316                 } else {
 317                         hash_type = migrate_hash;
 318                         stripe_count -= migrate_offset;
 319                 }
 320         }
 321
 322         if (stripe_count > 1) {
 323                 switch (hash_type & LMV_HASH_TYPE_MASK) {
 324                 case LMV_HASH_TYPE_ALL_CHARS:
 325                         stripe_index = lmv_hash_all_chars(stripe_count, name,
 326                                                           namelen);
 327                         break;
 328                 case LMV_HASH_TYPE_FNV_1A_64:
 329                         stripe_index = lmv_hash_fnv1a(stripe_count, name,
 330                                                       namelen);
 331                         break;
 332                 case LMV_HASH_TYPE_CRUSH:
 333                         stripe_index = lmv_hash_crush(stripe_count, name,
 334                                                       namelen);
 335                         break;
 336                 default:
 337                         return -EBADFD;
 338                 }
 339         }
 340
 341         LASSERT(stripe_index < stripe_count);
 342
 343         if (!new_layout && lmv_hash_is_migrating(saved_hash))
 344                 stripe_index += migrate_offset;
 345
 346         LASSERT(stripe_index < saved_count);
 347
 348         CDEBUG(D_INFO, "name %.*s hash=%#x/%#x idx=%d/%u/%u under %s layout\n",
 349                namelen, name, saved_hash, migrate_hash, stripe_index,
 350                saved_count, migrate_offset, new_layout ? "new" : "old");
 351
 352         return stripe_index;
 353 }
 354
 355 static inline int lmv_name_to_stripe_index(struct lmv_mds_md_v1 *lmv,
 356                                            const char *name, int namelen)
 357 {
 358         if (lmv->lmv_magic == LMV_MAGIC_V1)
 359                 return __lmv_name_to_stripe_index(lmv->lmv_hash_type,
 360                                                   lmv->lmv_stripe_count,
 361                                                   lmv->lmv_migrate_hash,
 362                                                   lmv->lmv_migrate_offset,
 363                                                   name, namelen, true);
 364
 365         if (lmv->lmv_magic == cpu_to_le32(LMV_MAGIC_V1))
 366                 return __lmv_name_to_stripe_index(
 367                                         le32_to_cpu(lmv->lmv_hash_type),
 368                                         le32_to_cpu(lmv->lmv_stripe_count),
 369                                         le32_to_cpu(lmv->lmv_migrate_hash),
 370                                         le32_to_cpu(lmv->lmv_migrate_offset),
 371                                         name, namelen, true);
 372
 373         return -EINVAL;
 374 }
 375
 376 static inline int lmv_name_to_stripe_index_old(struct lmv_mds_md_v1 *lmv,
 377                                                const char *name, int namelen)
 378 {
 379         if (lmv->lmv_magic == LMV_MAGIC_V1 ||
 380             lmv->lmv_magic == LMV_MAGIC_STRIPE)
 381                 return __lmv_name_to_stripe_index(lmv->lmv_hash_type,
 382                                                   lmv->lmv_stripe_count,
 383                                                   lmv->lmv_migrate_hash,
 384                                                   lmv->lmv_migrate_offset,
 385                                                   name, namelen, false);
 386
 387         if (lmv->lmv_magic == cpu_to_le32(LMV_MAGIC_V1) ||
 388             lmv->lmv_magic == cpu_to_le32(LMV_MAGIC_STRIPE))
 389                 return __lmv_name_to_stripe_index(
 390                                         le32_to_cpu(lmv->lmv_hash_type),
 391                                         le32_to_cpu(lmv->lmv_stripe_count),
 392                                         le32_to_cpu(lmv->lmv_migrate_hash),
 393                                         le32_to_cpu(lmv->lmv_migrate_offset),
 394                                         name, namelen, false);
 395
 396         return -EINVAL;
 397 }
 398
 399 static inline bool lmv_user_magic_supported(__u32 lum_magic)
 400 {
 401         return lum_magic == LMV_USER_MAGIC ||
 402                lum_magic == LMV_USER_MAGIC_SPECIFIC ||
 403                lum_magic == LMV_MAGIC_FOREIGN;
 404 }
 405
 406 /* master LMV is sane */
 407 static inline bool lmv_is_sane(const struct lmv_mds_md_v1 *lmv)
 408 {
 409         if (!lmv)
 410                 return false;
 411
 412         if (le32_to_cpu(lmv->lmv_magic) != LMV_MAGIC_V1)
 413                 goto insane;
 414
 415         if (le32_to_cpu(lmv->lmv_stripe_count) == 0)
 416                 goto insane;
 417
 418         if (!lmv_is_known_hash_type(le32_to_cpu(lmv->lmv_hash_type)))
 419                 goto insane;
 420
 421         return true;
 422 insane:
 423         LMV_DEBUG(D_ERROR, lmv, "insane");
 424         return false;
 425 }
 426
 427 /* LMV can be either master or stripe LMV */
 428 static inline bool lmv_is_sane2(const struct lmv_mds_md_v1 *lmv)
 429 {
 430         if (!lmv)
 431                 return false;
 432
 433         if (le32_to_cpu(lmv->lmv_magic) != LMV_MAGIC_V1 &&
 434             le32_to_cpu(lmv->lmv_magic) != LMV_MAGIC_STRIPE)
 435                 goto insane;
 436
 437         if (le32_to_cpu(lmv->lmv_stripe_count) == 0)
 438                 goto insane;
 439
 440         if (!lmv_is_known_hash_type(le32_to_cpu(lmv->lmv_hash_type)))
 441                 goto insane;
 442
 443         return true;
 444 insane:
 445         LMV_DEBUG(D_ERROR, lmv, "insane");
 446         return false;
 447 }
 448
 449 static inline bool lmv_is_splitting(const struct lmv_mds_md_v1 *lmv)
 450 {
 451         if (!lmv_is_sane2(lmv))
 452                 return false;
 453
 454         return lmv_hash_is_splitting(cpu_to_le32(lmv->lmv_hash_type));
 455 }
 456
 457 static inline bool lmv_is_merging(const struct lmv_mds_md_v1 *lmv)
 458 {
 459         if (!lmv_is_sane2(lmv))
 460                 return false;
 461
 462         return lmv_hash_is_merging(cpu_to_le32(lmv->lmv_hash_type));
 463 }
 464
 465 static inline bool lmv_is_migrating(const struct lmv_mds_md_v1 *lmv)
 466 {
 467         if (!lmv_is_sane(lmv))
 468                 return false;
 469
 470         return lmv_hash_is_migrating(cpu_to_le32(lmv->lmv_hash_type));
 471 }
 472
 473 static inline bool lmv_is_restriping(const struct lmv_mds_md_v1 *lmv)
 474 {
 475         if (!lmv_is_sane2(lmv))
 476                 return false;
 477
 478         return lmv_hash_is_splitting(cpu_to_le32(lmv->lmv_hash_type)) ||
 479                lmv_hash_is_merging(cpu_to_le32(lmv->lmv_hash_type));
 480 }
 481
 482 static inline bool lmv_is_layout_changing(const struct lmv_mds_md_v1 *lmv)
 483 {
 484         if (!lmv_is_sane2(lmv))
 485                 return false;
 486
 487         return lmv_hash_is_splitting(cpu_to_le32(lmv->lmv_hash_type)) ||
 488                lmv_hash_is_merging(cpu_to_le32(lmv->lmv_hash_type)) ||
 489                lmv_hash_is_migrating(cpu_to_le32(lmv->lmv_hash_type));
 490 }
 491
 492 #endif