4 Copyright (C) Andrew Tridgell 2006
6 This library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2 of the License, or (at your option) any later version.
11 This library 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 GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with this library; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include "lib/events/events.h"
23 #include "lib/tdb/include/tdb.h"
24 #include "system/network.h"
25 #include "system/filesys.h"
26 #include "../include/ctdb_private.h"
28 #include "lib/util/dlinklist.h"
31 find an attached ctdb_db handle given a name
33 struct ctdb_db_context *ctdb_db_handle(struct ctdb_context *ctdb, const char *name)
35 struct ctdb_db_context *tmp_db;
36 for (tmp_db=ctdb->db_list;tmp_db;tmp_db=tmp_db->next) {
37 if (strcmp(name, tmp_db->db_name) == 0) {
46 this is the dummy null procedure that all databases support
48 static int ctdb_null_func(struct ctdb_call_info *call)
54 this is a plain fetch procedure that all databases support
56 static int ctdb_fetch_func(struct ctdb_call_info *call)
58 call->reply_data = &call->record_data;
64 return the lmaster given a key
66 uint32_t ctdb_lmaster(struct ctdb_context *ctdb, const TDB_DATA *key)
68 uint32_t idx, lmaster;
70 idx = ctdb_hash(key) % ctdb->vnn_map->size;
71 lmaster = ctdb->vnn_map->map[idx];
78 construct an initial header for a record with no ltdb header yet
80 static void ltdb_initial_header(struct ctdb_db_context *ctdb_db,
82 struct ctdb_ltdb_header *header)
85 /* initial dmaster is the lmaster */
86 header->dmaster = ctdb_lmaster(ctdb_db->ctdb, &key);
87 header->laccessor = header->dmaster;
93 fetch a record from the ltdb, separating out the header information
94 and returning the body of the record. A valid (initial) header is
95 returned if the record is not present
97 int ctdb_ltdb_fetch(struct ctdb_db_context *ctdb_db,
98 TDB_DATA key, struct ctdb_ltdb_header *header,
99 TALLOC_CTX *mem_ctx, TDB_DATA *data)
102 struct ctdb_context *ctdb = ctdb_db->ctdb;
104 rec = tdb_fetch(ctdb_db->ltdb->tdb, key);
105 if (rec.dsize < sizeof(*header)) {
107 /* return an initial header */
108 if (rec.dptr) free(rec.dptr);
109 ltdb_initial_header(ctdb_db, key, header);
114 ctdb_ltdb_store(ctdb_db, key, header, d2);
118 *header = *(struct ctdb_ltdb_header *)rec.dptr;
121 data->dsize = rec.dsize - sizeof(struct ctdb_ltdb_header);
122 data->dptr = talloc_memdup(mem_ctx,
123 sizeof(struct ctdb_ltdb_header)+rec.dptr,
129 CTDB_NO_MEMORY(ctdb, data->dptr);
137 fetch a record from the ltdb, separating out the header information
138 and returning the body of the record. A valid (initial) header is
139 returned if the record is not present
141 int ctdb_ltdb_store(struct ctdb_db_context *ctdb_db, TDB_DATA key,
142 struct ctdb_ltdb_header *header, TDB_DATA data)
144 struct ctdb_context *ctdb = ctdb_db->ctdb;
148 rec.dsize = sizeof(*header) + data.dsize;
149 rec.dptr = talloc_size(ctdb, rec.dsize);
150 CTDB_NO_MEMORY(ctdb, rec.dptr);
152 memcpy(rec.dptr, header, sizeof(*header));
153 memcpy(rec.dptr + sizeof(*header), data.dptr, data.dsize);
155 ret = tdb_store(ctdb_db->ltdb->tdb, key, rec, TDB_REPLACE);
156 talloc_free(rec.dptr);
163 lock a record in the ltdb, given a key
165 int ctdb_ltdb_lock(struct ctdb_db_context *ctdb_db, TDB_DATA key)
167 return tdb_chainlock(ctdb_db->ltdb->tdb, key);
171 unlock a record in the ltdb, given a key
173 int ctdb_ltdb_unlock(struct ctdb_db_context *ctdb_db, TDB_DATA key)
175 int ret = tdb_chainunlock(ctdb_db->ltdb->tdb, key);
177 DEBUG(0,("tdb_chainunlock failed\n"));
182 struct lock_fetch_state {
183 struct ctdb_context *ctdb;
184 void (*recv_pkt)(void *, uint8_t *, uint32_t);
186 struct ctdb_req_header *hdr;
190 called when we should retry the operation
192 static void lock_fetch_callback(void *p)
194 struct lock_fetch_state *state = talloc_get_type(p, struct lock_fetch_state);
195 state->recv_pkt(state->recv_context, (uint8_t *)state->hdr, state->hdr->length);
197 DEBUG(2,(__location__ " PACKET REQUEUED\n"));
202 do a non-blocking ltdb_lock, deferring this ctdb request until we
205 It does the following:
207 1) tries to get the chainlock. If it succeeds, then it returns 0
209 2) if it fails to get a chainlock immediately then it sets up a
210 non-blocking chainlock via ctdb_lockwait, and when it gets the
211 chainlock it re-submits this ctdb request to the main packet
214 This effectively queues all ctdb requests that cannot be
215 immediately satisfied until it can get the lock. This means that
216 the main ctdb daemon will not block waiting for a chainlock held by
219 There are 3 possible return values:
221 0: means that it got the lock immediately.
222 -1: means that it failed to get the lock, and won't retry
223 -2: means that it failed to get the lock immediately, but will retry
225 int ctdb_ltdb_lock_requeue(struct ctdb_db_context *ctdb_db,
226 TDB_DATA key, struct ctdb_req_header *hdr,
227 void (*recv_pkt)(void *, uint8_t *, uint32_t ),
231 struct tdb_context *tdb = ctdb_db->ltdb->tdb;
232 struct lockwait_handle *h;
233 struct lock_fetch_state *state;
235 ret = tdb_chainlock_nonblock(tdb, key);
238 !(errno == EACCES || errno == EAGAIN || errno == EDEADLK)) {
239 /* a hard failure - don't try again */
243 /* when torturing, ensure we test the contended path */
244 if ((ctdb_db->ctdb->flags & CTDB_FLAG_TORTURE) &&
247 tdb_chainunlock(tdb, key);
250 /* first the non-contended path */
255 state = talloc(ctdb_db, struct lock_fetch_state);
256 state->ctdb = ctdb_db->ctdb;
258 state->recv_pkt = recv_pkt;
259 state->recv_context = recv_context;
261 /* now the contended path */
262 h = ctdb_lockwait(ctdb_db, key, lock_fetch_callback, state);
264 tdb_chainunlock(tdb, key);
268 /* we need to move the packet off the temporary context in ctdb_recv_pkt(),
269 so it won't be freed yet */
270 talloc_steal(state, hdr);
271 talloc_steal(state, h);
273 /* now tell the caller than we will retry asynchronously */
278 a varient of ctdb_ltdb_lock_requeue that also fetches the record
280 int ctdb_ltdb_lock_fetch_requeue(struct ctdb_db_context *ctdb_db,
281 TDB_DATA key, struct ctdb_ltdb_header *header,
282 struct ctdb_req_header *hdr, TDB_DATA *data,
283 void (*recv_pkt)(void *, uint8_t *, uint32_t ),
288 ret = ctdb_ltdb_lock_requeue(ctdb_db, key, hdr, recv_pkt, recv_context);
290 ret = ctdb_ltdb_fetch(ctdb_db, key, header, hdr, data);
292 ctdb_ltdb_unlock(ctdb_db, key);
300 a client has asked to attach a new database
302 int32_t ctdb_control_db_attach(struct ctdb_context *ctdb, TDB_DATA indata,
305 const char *db_name = (const char *)indata.dptr;
306 struct ctdb_db_context *ctdb_db, *tmp_db;
309 /* see if we already have this name */
310 for (tmp_db=ctdb->db_list;tmp_db;tmp_db=tmp_db->next) {
311 if (strcmp(db_name, tmp_db->db_name) == 0) {
312 /* this is not an error */
313 outdata->dptr = (uint8_t *)&tmp_db->db_id;
314 outdata->dsize = sizeof(tmp_db->db_id);
319 ctdb_db = talloc_zero(ctdb, struct ctdb_db_context);
320 CTDB_NO_MEMORY(ctdb, ctdb_db);
322 ctdb_db->ctdb = ctdb;
323 ctdb_db->db_name = talloc_strdup(ctdb_db, db_name);
324 CTDB_NO_MEMORY(ctdb, ctdb_db->db_name);
326 ctdb_db->db_id = ctdb_hash(&indata);
328 outdata->dptr = (uint8_t *)&ctdb_db->db_id;
329 outdata->dsize = sizeof(ctdb_db->db_id);
331 /* check for hash collisions */
332 for (tmp_db=ctdb->db_list;tmp_db;tmp_db=tmp_db->next) {
333 if (tmp_db->db_id == ctdb_db->db_id) {
334 DEBUG(0,("db_id 0x%x hash collision. name1='%s' name2='%s'\n",
335 db_name, tmp_db->db_name));
336 talloc_free(ctdb_db);
341 if (ctdb->db_directory == NULL) {
342 ctdb->db_directory = VARDIR "/ctdb";
345 /* make sure the db directory exists */
346 if (mkdir(ctdb->db_directory, 0700) == -1 && errno != EEXIST) {
347 DEBUG(0,(__location__ " Unable to create ctdb directory '%s'\n",
348 ctdb->db_directory));
349 talloc_free(ctdb_db);
353 /* open the database */
354 ctdb_db->db_path = talloc_asprintf(ctdb_db, "%s/%s.%u",
358 ctdb_db->ltdb = tdb_wrap_open(ctdb, ctdb_db->db_path, 0,
359 TDB_CLEAR_IF_FIRST, O_CREAT|O_RDWR, 0666);
360 if (ctdb_db->ltdb == NULL) {
361 DEBUG(0,("Failed to open tdb '%s'\n", ctdb_db->db_path));
362 talloc_free(ctdb_db);
366 DLIST_ADD(ctdb->db_list, ctdb_db);
369 all databases support the "null" function. we need this in
370 order to do forced migration of records
372 ret = ctdb_daemon_set_call(ctdb, ctdb_db->db_id, ctdb_null_func, CTDB_NULL_FUNC);
374 DEBUG(0,("Failed to setup null function for '%s'\n", ctdb_db->db_name));
375 talloc_free(ctdb_db);
380 all databases support the "fetch" function. we need this
381 for efficient Samba3 ctdb fetch
383 ret = ctdb_daemon_set_call(ctdb, ctdb_db->db_id, ctdb_fetch_func, CTDB_FETCH_FUNC);
385 DEBUG(0,("Failed to setup fetch function for '%s'\n", ctdb_db->db_name));
386 talloc_free(ctdb_db);
390 /* tell all the other nodes about this database */
391 ctdb_daemon_send_control(ctdb, CTDB_BROADCAST_VNN, 0,
392 CTDB_CONTROL_DB_ATTACH, CTDB_CTRL_FLAG_NOREPLY,
395 DEBUG(1,("Attached to database '%s'\n", ctdb_db->db_path));