drivers/staging/lustre/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  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2013, 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 "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_default_count;
  50         __u32   lsm_md_default_index;
  51         char    lsm_md_pool_name[LOV_MAXPOOLNAME + 1];
  52         struct lmv_oinfo lsm_md_oinfo[0];
  53 };
  54
  55 static inline bool
  56 lsm_md_eq(const struct lmv_stripe_md *lsm1, const struct lmv_stripe_md *lsm2)
  57 {
  58         __u32 idx;
  59
  60         if (lsm1->lsm_md_magic != lsm2->lsm_md_magic ||
  61             lsm1->lsm_md_stripe_count != lsm2->lsm_md_stripe_count ||
  62             lsm1->lsm_md_master_mdt_index != lsm2->lsm_md_master_mdt_index ||
  63             lsm1->lsm_md_hash_type != lsm2->lsm_md_hash_type ||
  64             lsm1->lsm_md_layout_version != lsm2->lsm_md_layout_version ||
  65             !strcmp(lsm1->lsm_md_pool_name, lsm2->lsm_md_pool_name))
  66                 return false;
  67
  68         for (idx = 0; idx < lsm1->lsm_md_stripe_count; idx++) {
  69                 if (!lu_fid_eq(&lsm1->lsm_md_oinfo[idx].lmo_fid,
  70                                &lsm2->lsm_md_oinfo[idx].lmo_fid))
  71                         return false;
  72         }
  73
  74         return true;
  75 }
  76
  77 union lmv_mds_md;
  78
  79 int lmv_unpack_md(struct obd_export *exp, struct lmv_stripe_md **lsmp,
  80                   const union lmv_mds_md *lmm, int stripe_count);
  81
  82 static inline int lmv_alloc_memmd(struct lmv_stripe_md **lsmp, int stripe_count)
  83 {
  84         return lmv_unpack_md(NULL, lsmp, NULL, stripe_count);
  85 }
  86
  87 static inline void lmv_free_memmd(struct lmv_stripe_md *lsm)
  88 {
  89         lmv_unpack_md(NULL, &lsm, NULL, 0);
  90 }
  91
  92 static inline void lmv1_le_to_cpu(struct lmv_mds_md_v1 *lmv_dst,
  93                                   const struct lmv_mds_md_v1 *lmv_src)
  94 {
  95         __u32 i;
  96
  97         lmv_dst->lmv_magic = le32_to_cpu(lmv_src->lmv_magic);
  98         lmv_dst->lmv_stripe_count = le32_to_cpu(lmv_src->lmv_stripe_count);
  99         lmv_dst->lmv_master_mdt_index =
 100                 le32_to_cpu(lmv_src->lmv_master_mdt_index);
 101         lmv_dst->lmv_hash_type = le32_to_cpu(lmv_src->lmv_hash_type);
 102         lmv_dst->lmv_layout_version = le32_to_cpu(lmv_src->lmv_layout_version);
 103
 104         for (i = 0; i < lmv_src->lmv_stripe_count; i++)
 105                 fid_le_to_cpu(&lmv_dst->lmv_stripe_fids[i],
 106                               &lmv_src->lmv_stripe_fids[i]);
 107 }
 108
 109 static inline void lmv_le_to_cpu(union lmv_mds_md *lmv_dst,
 110                                  const union lmv_mds_md *lmv_src)
 111 {
 112         switch (le32_to_cpu(lmv_src->lmv_magic)) {
 113         case LMV_MAGIC_V1:
 114                 lmv1_le_to_cpu(&lmv_dst->lmv_md_v1, &lmv_src->lmv_md_v1);
 115                 break;
 116         default:
 117                 break;
 118         }
 119 }
 120
 121 /* This hash is only for testing purpose */
 122 static inline unsigned int
 123 lmv_hash_all_chars(unsigned int count, const char *name, int namelen)
 124 {
 125         const unsigned char *p = (const unsigned char *)name;
 126         unsigned int c = 0;
 127
 128         while (--namelen >= 0)
 129                 c += p[namelen];
 130
 131         c = c % count;
 132
 133         return c;
 134 }
 135
 136 static inline unsigned int
 137 lmv_hash_fnv1a(unsigned int count, const char *name, int namelen)
 138 {
 139         __u64 hash;
 140
 141         hash = lustre_hash_fnv_1a_64(name, namelen);
 142
 143         return do_div(hash, count);
 144 }
 145
 146 static inline int lmv_name_to_stripe_index(__u32 lmv_hash_type,
 147                                            unsigned int stripe_count,
 148                                            const char *name, int namelen)
 149 {
 150         __u32 hash_type = lmv_hash_type & LMV_HASH_TYPE_MASK;
 151         int idx;
 152
 153         LASSERT(namelen > 0);
 154         if (stripe_count <= 1)
 155                 return 0;
 156
 157         /* for migrating object, always start from 0 stripe */
 158         if (lmv_hash_type & LMV_HASH_FLAG_MIGRATION)
 159                 return 0;
 160
 161         switch (hash_type) {
 162         case LMV_HASH_TYPE_ALL_CHARS:
 163                 idx = lmv_hash_all_chars(stripe_count, name, namelen);
 164                 break;
 165         case LMV_HASH_TYPE_FNV_1A_64:
 166                 idx = lmv_hash_fnv1a(stripe_count, name, namelen);
 167                 break;
 168         default:
 169                 idx = -EBADFD;
 170                 break;
 171         }
 172         CDEBUG(D_INFO, "name %.*s hash_type %d idx %d\n", namelen, name,
 173                hash_type, idx);
 174
 175         return idx;
 176 }
 177
 178 static inline bool lmv_is_known_hash_type(__u32 type)
 179 {
 180         return (type & LMV_HASH_TYPE_MASK) == LMV_HASH_TYPE_FNV_1A_64 ||
 181                (type & LMV_HASH_TYPE_MASK) == LMV_HASH_TYPE_ALL_CHARS;
 182 }
 183
 184 #endif