ctdb/common/ctdb_ltdb.c

   1 /*
   2    ctdb ltdb code
   3
   4    Copyright (C) Andrew Tridgell  2006
   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 as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "lib/events/events.h"
  22 #include "lib/tdb/include/tdb.h"
  23 #include "system/network.h"
  24 #include "system/filesys.h"
  25 #include "../include/ctdb_private.h"
  26 #include "db_wrap.h"
  27 #include "lib/util/dlinklist.h"
  28
  29 /*
  30   find an attached ctdb_db handle given a name
  31  */
  32 struct ctdb_db_context *ctdb_db_handle(struct ctdb_context *ctdb, const char *name)
  33 {
  34         struct ctdb_db_context *tmp_db;
  35         for (tmp_db=ctdb->db_list;tmp_db;tmp_db=tmp_db->next) {
  36                 if (strcmp(name, tmp_db->db_name) == 0) {
  37                         return tmp_db;
  38                 }
  39         }
  40         return NULL;
  41 }
  42
  43
  44 /*
  45   return the lmaster given a key
  46 */
  47 uint32_t ctdb_lmaster(struct ctdb_context *ctdb, const TDB_DATA *key)
  48 {
  49         uint32_t idx, lmaster;
  50
  51         idx = ctdb_hash(key) % ctdb->vnn_map->size;
  52         lmaster = ctdb->vnn_map->map[idx];
  53
  54         return lmaster;
  55 }
  56
  57
  58 /*
  59   construct an initial header for a record with no ltdb header yet
  60 */
  61 static void ltdb_initial_header(struct ctdb_db_context *ctdb_db,
  62                                 TDB_DATA key,
  63                                 struct ctdb_ltdb_header *header)
  64 {
  65         ZERO_STRUCTP(header);
  66         /* initial dmaster is the lmaster */
  67         header->dmaster = ctdb_lmaster(ctdb_db->ctdb, &key);
  68         header->laccessor = header->dmaster;
  69 }
  70
  71
  72 /*
  73   fetch a record from the ltdb, separating out the header information
  74   and returning the body of the record. A valid (initial) header is
  75   returned if the record is not present
  76 */
  77 int ctdb_ltdb_fetch(struct ctdb_db_context *ctdb_db,
  78                     TDB_DATA key, struct ctdb_ltdb_header *header,
  79                     TALLOC_CTX *mem_ctx, TDB_DATA *data)
  80 {
  81         TDB_DATA rec;
  82         struct ctdb_context *ctdb = ctdb_db->ctdb;
  83
  84         rec = tdb_fetch(ctdb_db->ltdb->tdb, key);
  85         if (rec.dsize < sizeof(*header)) {
  86                 TDB_DATA d2;
  87                 /* return an initial header */
  88                 if (rec.dptr) free(rec.dptr);
  89                 if (ctdb->vnn_map == NULL) {
  90                         /* called from the client */
  91                         ZERO_STRUCTP(data);
  92                         header->dmaster = (uint32_t)-1;
  93                         return -1;
  94                 }
  95                 ltdb_initial_header(ctdb_db, key, header);
  96                 ZERO_STRUCT(d2);
  97                 if (data) {
  98                         *data = d2;
  99                 }
 100                 ctdb_ltdb_store(ctdb_db, key, header, d2);
 101                 return 0;
 102         }
 103
 104         *header = *(struct ctdb_ltdb_header *)rec.dptr;
 105
 106         if (data) {
 107                 data->dsize = rec.dsize - sizeof(struct ctdb_ltdb_header);
 108                 data->dptr = talloc_memdup(mem_ctx,
 109                                            sizeof(struct ctdb_ltdb_header)+rec.dptr,
 110                                            data->dsize);
 111         }
 112
 113         free(rec.dptr);
 114         if (data) {
 115                 CTDB_NO_MEMORY(ctdb, data->dptr);
 116         }
 117
 118         return 0;
 119 }
 120
 121
 122 /*
 123   write a record to a normal database
 124 */
 125 int ctdb_ltdb_store(struct ctdb_db_context *ctdb_db, TDB_DATA key,
 126                     struct ctdb_ltdb_header *header, TDB_DATA data)
 127 {
 128         struct ctdb_context *ctdb = ctdb_db->ctdb;
 129         TDB_DATA rec;
 130         int ret;
 131
 132         if (ctdb->flags & CTDB_FLAG_TORTURE) {
 133                 struct ctdb_ltdb_header *h2;
 134                 rec = tdb_fetch(ctdb_db->ltdb->tdb, key);
 135                 h2 = (struct ctdb_ltdb_header *)rec.dptr;
 136                 if (rec.dptr && rec.dsize >= sizeof(h2) && h2->rsn > header->rsn) {
 137                         DEBUG(DEBUG_CRIT,("RSN regression! %llu %llu\n",
 138                                  (unsigned long long)h2->rsn, (unsigned long long)header->rsn));
 139                 }
 140                 if (rec.dptr) free(rec.dptr);
 141         }
 142
 143         rec.dsize = sizeof(*header) + data.dsize;
 144         rec.dptr = talloc_size(ctdb, rec.dsize);
 145         CTDB_NO_MEMORY(ctdb, rec.dptr);
 146
 147         memcpy(rec.dptr, header, sizeof(*header));
 148         memcpy(rec.dptr + sizeof(*header), data.dptr, data.dsize);
 149
 150         ret = tdb_store(ctdb_db->ltdb->tdb, key, rec, TDB_REPLACE);
 151         if (ret != 0) {
 152                 DEBUG(DEBUG_ERR, (__location__ " Failed to store dynamic data\n"));
 153         }
 154
 155         talloc_free(rec.dptr);
 156
 157         return ret;
 158 }
 159
 160 /*
 161   lock a record in the ltdb, given a key
 162  */
 163 int ctdb_ltdb_lock(struct ctdb_db_context *ctdb_db, TDB_DATA key)
 164 {
 165         return tdb_chainlock(ctdb_db->ltdb->tdb, key);
 166 }
 167
 168 /*
 169   unlock a record in the ltdb, given a key
 170  */
 171 int ctdb_ltdb_unlock(struct ctdb_db_context *ctdb_db, TDB_DATA key)
 172 {
 173         int ret = tdb_chainunlock(ctdb_db->ltdb->tdb, key);
 174         if (ret != 0) {
 175                 DEBUG(DEBUG_ERR,("tdb_chainunlock failed\n"));
 176         }
 177         return ret;
 178 }