/* Unix SMB/CIFS implementation. Database interface wrapper around ctdbd Copyright (C) Volker Lendecke 2007-2009 Copyright (C) Michael Adam 2009 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "includes.h" #ifdef CLUSTER_SUPPORT #include "ctdb.h" #include "ctdb_private.h" #include "ctdbd_conn.h" #include "g_lock.h" struct db_ctdb_transaction_handle { struct db_ctdb_ctx *ctx; /* * we store the reads and writes done under a transaction: * - one list stores both reads and writes (m_all), * - the other just writes (m_write) */ struct ctdb_marshall_buffer *m_all; struct ctdb_marshall_buffer *m_write; uint32_t nesting; bool nested_cancel; char *lock_name; }; struct db_ctdb_ctx { struct db_context *db; struct tdb_wrap *wtdb; uint32 db_id; struct db_ctdb_transaction_handle *transaction; struct g_lock_ctx *lock_ctx; }; struct db_ctdb_rec { struct db_ctdb_ctx *ctdb_ctx; struct ctdb_ltdb_header header; struct timeval lock_time; }; static NTSTATUS tdb_error_to_ntstatus(struct tdb_context *tdb) { NTSTATUS status; enum TDB_ERROR tret = tdb_error(tdb); switch (tret) { case TDB_ERR_EXISTS: status = NT_STATUS_OBJECT_NAME_COLLISION; break; case TDB_ERR_NOEXIST: status = NT_STATUS_OBJECT_NAME_NOT_FOUND; break; default: status = NT_STATUS_INTERNAL_DB_CORRUPTION; break; } return status; } /** * fetch a record from the tdb, separating out the header * information and returning the body of the record. */ static NTSTATUS db_ctdb_ltdb_fetch(struct db_ctdb_ctx *db, TDB_DATA key, struct ctdb_ltdb_header *header, TALLOC_CTX *mem_ctx, TDB_DATA *data) { TDB_DATA rec; NTSTATUS status; rec = tdb_fetch(db->wtdb->tdb, key); if (rec.dsize < sizeof(struct ctdb_ltdb_header)) { status = NT_STATUS_NOT_FOUND; if (data) { ZERO_STRUCTP(data); } if (header) { header->dmaster = (uint32_t)-1; header->rsn = 0; } goto done; } if (header) { *header = *(struct ctdb_ltdb_header *)rec.dptr; } if (data) { data->dsize = rec.dsize - sizeof(struct ctdb_ltdb_header); if (data->dsize == 0) { data->dptr = NULL; } else { data->dptr = (unsigned char *)talloc_memdup(mem_ctx, rec.dptr + sizeof(struct ctdb_ltdb_header), data->dsize); if (data->dptr == NULL) { status = NT_STATUS_NO_MEMORY; goto done; } } } status = NT_STATUS_OK; done: SAFE_FREE(rec.dptr); return status; } /* * Store a record together with the ctdb record header * in the local copy of the database. */ static NTSTATUS db_ctdb_ltdb_store(struct db_ctdb_ctx *db, TDB_DATA key, struct ctdb_ltdb_header *header, TDB_DATA data) { TALLOC_CTX *tmp_ctx = talloc_stackframe(); TDB_DATA rec; int ret; rec.dsize = data.dsize + sizeof(struct ctdb_ltdb_header); rec.dptr = (uint8_t *)talloc_size(tmp_ctx, rec.dsize); if (rec.dptr == NULL) { talloc_free(tmp_ctx); return NT_STATUS_NO_MEMORY; } memcpy(rec.dptr, header, sizeof(struct ctdb_ltdb_header)); memcpy(sizeof(struct ctdb_ltdb_header) + (uint8_t *)rec.dptr, data.dptr, data.dsize); ret = tdb_store(db->wtdb->tdb, key, rec, TDB_REPLACE); talloc_free(tmp_ctx); return (ret == 0) ? NT_STATUS_OK : tdb_error_to_ntstatus(db->wtdb->tdb); } /* form a ctdb_rec_data record from a key/data pair note that header may be NULL. If not NULL then it is included in the data portion of the record */ static struct ctdb_rec_data *db_ctdb_marshall_record(TALLOC_CTX *mem_ctx, uint32_t reqid, TDB_DATA key, struct ctdb_ltdb_header *header, TDB_DATA data) { size_t length; struct ctdb_rec_data *d; length = offsetof(struct ctdb_rec_data, data) + key.dsize + data.dsize + (header?sizeof(*header):0); d = (struct ctdb_rec_data *)talloc_size(mem_ctx, length); if (d == NULL) { return NULL; } d->length = length; d->reqid = reqid; d->keylen = key.dsize; memcpy(&d->data[0], key.dptr, key.dsize); if (header) { d->datalen = data.dsize + sizeof(*header); memcpy(&d->data[key.dsize], header, sizeof(*header)); memcpy(&d->data[key.dsize+sizeof(*header)], data.dptr, data.dsize); } else { d->datalen = data.dsize; memcpy(&d->data[key.dsize], data.dptr, data.dsize); } return d; } /* helper function for marshalling multiple records */ static struct ctdb_marshall_buffer *db_ctdb_marshall_add(TALLOC_CTX *mem_ctx, struct ctdb_marshall_buffer *m, uint64_t db_id, uint32_t reqid, TDB_DATA key, struct ctdb_ltdb_header *header, TDB_DATA data) { struct ctdb_rec_data *r; size_t m_size, r_size; struct ctdb_marshall_buffer *m2 = NULL; r = db_ctdb_marshall_record(talloc_tos(), reqid, key, header, data); if (r == NULL) { talloc_free(m); return NULL; } if (m == NULL) { m = (struct ctdb_marshall_buffer *)talloc_zero_size( mem_ctx, offsetof(struct ctdb_marshall_buffer, data)); if (m == NULL) { goto done; } m->db_id = db_id; } m_size = talloc_get_size(m); r_size = talloc_get_size(r); m2 = (struct ctdb_marshall_buffer *)talloc_realloc_size( mem_ctx, m, m_size + r_size); if (m2 == NULL) { talloc_free(m); goto done; } memcpy(m_size + (uint8_t *)m2, r, r_size); m2->count++; done: talloc_free(r); return m2; } /* we've finished marshalling, return a data blob with the marshalled records */ static TDB_DATA db_ctdb_marshall_finish(struct ctdb_marshall_buffer *m) { TDB_DATA data; data.dptr = (uint8_t *)m; data.dsize = talloc_get_size(m); return data; } /* loop over a marshalling buffer - pass r==NULL to start - loop the number of times indicated by m->count */ static struct ctdb_rec_data *db_ctdb_marshall_loop_next(struct ctdb_marshall_buffer *m, struct ctdb_rec_data *r, uint32_t *reqid, struct ctdb_ltdb_header *header, TDB_DATA *key, TDB_DATA *data) { if (r == NULL) { r = (struct ctdb_rec_data *)&m->data[0]; } else { r = (struct ctdb_rec_data *)(r->length + (uint8_t *)r); } if (reqid != NULL) { *reqid = r->reqid; } if (key != NULL) { key->dptr = &r->data[0]; key->dsize = r->keylen; } if (data != NULL) { data->dptr = &r->data[r->keylen]; data->dsize = r->datalen; if (header != NULL) { data->dptr += sizeof(*header); data->dsize -= sizeof(*header); } } if (header != NULL) { if (r->datalen < sizeof(*header)) { return NULL; } *header = *(struct ctdb_ltdb_header *)&r->data[r->keylen]; } return r; } /** * CTDB transaction destructor */ static int db_ctdb_transaction_destructor(struct db_ctdb_transaction_handle *h) { NTSTATUS status; status = g_lock_unlock(h->ctx->lock_ctx, h->lock_name); if (!NT_STATUS_IS_OK(status)) { DEBUG(0, ("g_lock_unlock failed: %s\n", nt_errstr(status))); return -1; } return 0; } /** * CTDB dbwrap API: transaction_start function * starts a transaction on a persistent database */ static int db_ctdb_transaction_start(struct db_context *db) { struct db_ctdb_transaction_handle *h; NTSTATUS status; struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); if (!db->persistent) { DEBUG(0,("transactions not supported on non-persistent database 0x%08x\n", ctx->db_id)); return -1; } if (ctx->transaction) { ctx->transaction->nesting++; return 0; } h = talloc_zero(db, struct db_ctdb_transaction_handle); if (h == NULL) { DEBUG(0,(__location__ " oom for transaction handle\n")); return -1; } h->ctx = ctx; h->lock_name = talloc_asprintf(h, "transaction_db_0x%08x", (unsigned int)ctx->db_id); if (h->lock_name == NULL) { DEBUG(0, ("talloc_asprintf failed\n")); TALLOC_FREE(h); return -1; } /* * Wait a day, i.e. forever... */ status = g_lock_lock(ctx->lock_ctx, h->lock_name, G_LOCK_WRITE, timeval_set(86400, 0)); if (!NT_STATUS_IS_OK(status)) { DEBUG(0, ("g_lock_lock failed: %s\n", nt_errstr(status))); TALLOC_FREE(h); return -1; } talloc_set_destructor(h, db_ctdb_transaction_destructor); ctx->transaction = h; DEBUG(5,(__location__ " Started transaction on db 0x%08x\n", ctx->db_id)); return 0; } static bool pull_newest_from_marshall_buffer(struct ctdb_marshall_buffer *buf, TDB_DATA key, struct ctdb_ltdb_header *pheader, TALLOC_CTX *mem_ctx, TDB_DATA *pdata) { struct ctdb_rec_data *rec = NULL; struct ctdb_ltdb_header h; bool found = false; TDB_DATA data; int i; if (buf == NULL) { return false; } ZERO_STRUCT(h); ZERO_STRUCT(data); /* * Walk the list of records written during this * transaction. If we want to read one we have already * written, return the last written sample. Thus we do not do * a "break;" for the first hit, this record might have been * overwritten later. */ for (i=0; i<buf->count; i++) { TDB_DATA tkey, tdata; uint32_t reqid; struct ctdb_ltdb_header hdr; ZERO_STRUCT(hdr); rec = db_ctdb_marshall_loop_next(buf, rec, &reqid, &hdr, &tkey, &tdata); if (rec == NULL) { return false; } if (tdb_data_equal(key, tkey)) { found = true; data = tdata; h = hdr; } } if (!found) { return false; } if (pdata != NULL) { data.dptr = (uint8_t *)talloc_memdup(mem_ctx, data.dptr, data.dsize); if ((data.dsize != 0) && (data.dptr == NULL)) { return false; } *pdata = data; } if (pheader != NULL) { *pheader = h; } return true; } /* fetch a record inside a transaction */ static int db_ctdb_transaction_fetch(struct db_ctdb_ctx *db, TALLOC_CTX *mem_ctx, TDB_DATA key, TDB_DATA *data) { struct db_ctdb_transaction_handle *h = db->transaction; NTSTATUS status; bool found; found = pull_newest_from_marshall_buffer(h->m_write, key, NULL, mem_ctx, data); if (found) { return 0; } status = db_ctdb_ltdb_fetch(h->ctx, key, NULL, mem_ctx, data); if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) { *data = tdb_null; } else if (!NT_STATUS_IS_OK(status)) { return -1; } h->m_all = db_ctdb_marshall_add(h, h->m_all, h->ctx->db_id, 1, key, NULL, *data); if (h->m_all == NULL) { DEBUG(0,(__location__ " Failed to add to marshalling " "record\n")); data->dsize = 0; talloc_free(data->dptr); return -1; } return 0; } static NTSTATUS db_ctdb_store_transaction(struct db_record *rec, TDB_DATA data, int flag); static NTSTATUS db_ctdb_delete_transaction(struct db_record *rec); static struct db_record *db_ctdb_fetch_locked_transaction(struct db_ctdb_ctx *ctx, TALLOC_CTX *mem_ctx, TDB_DATA key) { struct db_record *result; TDB_DATA ctdb_data; if (!(result = talloc(mem_ctx, struct db_record))) { DEBUG(0, ("talloc failed\n")); return NULL; } result->private_data = ctx->transaction; result->key.dsize = key.dsize; result->key.dptr = (uint8 *)talloc_memdup(result, key.dptr, key.dsize); if (result->key.dptr == NULL) { DEBUG(0, ("talloc failed\n")); TALLOC_FREE(result); return NULL; } result->store = db_ctdb_store_transaction; result->delete_rec = db_ctdb_delete_transaction; if (pull_newest_from_marshall_buffer(ctx->transaction->m_write, key, NULL, result, &result->value)) { return result; } ctdb_data = tdb_fetch(ctx->wtdb->tdb, key); if (ctdb_data.dptr == NULL) { /* create the record */ result->value = tdb_null; return result; } result->value.dsize = ctdb_data.dsize - sizeof(struct ctdb_ltdb_header); result->value.dptr = NULL; if ((result->value.dsize != 0) && !(result->value.dptr = (uint8 *)talloc_memdup( result, ctdb_data.dptr + sizeof(struct ctdb_ltdb_header), result->value.dsize))) { DEBUG(0, ("talloc failed\n")); TALLOC_FREE(result); } SAFE_FREE(ctdb_data.dptr); return result; } static int db_ctdb_record_destructor(struct db_record **recp) { struct db_record *rec = talloc_get_type_abort(*recp, struct db_record); struct db_ctdb_transaction_handle *h = talloc_get_type_abort( rec->private_data, struct db_ctdb_transaction_handle); int ret = h->ctx->db->transaction_commit(h->ctx->db); if (ret != 0) { DEBUG(0,(__location__ " transaction_commit failed\n")); } return 0; } /* auto-create a transaction for persistent databases */ static struct db_record *db_ctdb_fetch_locked_persistent(struct db_ctdb_ctx *ctx, TALLOC_CTX *mem_ctx, TDB_DATA key) { int res; struct db_record *rec, **recp; res = db_ctdb_transaction_start(ctx->db); if (res == -1) { return NULL; } rec = db_ctdb_fetch_locked_transaction(ctx, mem_ctx, key); if (rec == NULL) { ctx->db->transaction_cancel(ctx->db); return NULL; } /* destroy this transaction when we release the lock */ recp = talloc(rec, struct db_record *); if (recp == NULL) { ctx->db->transaction_cancel(ctx->db); talloc_free(rec); return NULL; } *recp = rec; talloc_set_destructor(recp, db_ctdb_record_destructor); return rec; } /* stores a record inside a transaction */ static NTSTATUS db_ctdb_transaction_store(struct db_ctdb_transaction_handle *h, TDB_DATA key, TDB_DATA data) { TALLOC_CTX *tmp_ctx = talloc_new(h); TDB_DATA rec; struct ctdb_ltdb_header header; ZERO_STRUCT(header); /* we need the header so we can update the RSN */ if (!pull_newest_from_marshall_buffer(h->m_write, key, &header, NULL, NULL)) { rec = tdb_fetch(h->ctx->wtdb->tdb, key); if (rec.dptr != NULL) { memcpy(&header, rec.dptr, sizeof(struct ctdb_ltdb_header)); rec.dsize -= sizeof(struct ctdb_ltdb_header); /* * a special case, we are writing the same * data that is there now */ if (data.dsize == rec.dsize && memcmp(data.dptr, rec.dptr + sizeof(struct ctdb_ltdb_header), data.dsize) == 0) { SAFE_FREE(rec.dptr); talloc_free(tmp_ctx); return NT_STATUS_OK; } } SAFE_FREE(rec.dptr); } header.dmaster = get_my_vnn(); header.rsn++; h->m_all = db_ctdb_marshall_add(h, h->m_all, h->ctx->db_id, 0, key, NULL, data); if (h->m_all == NULL) { DEBUG(0,(__location__ " Failed to add to marshalling " "record\n")); talloc_free(tmp_ctx); return NT_STATUS_NO_MEMORY; } h->m_write = db_ctdb_marshall_add(h, h->m_write, h->ctx->db_id, 0, key, &header, data); if (h->m_write == NULL) { DEBUG(0,(__location__ " Failed to add to marshalling record\n")); talloc_free(tmp_ctx); return NT_STATUS_NO_MEMORY; } talloc_free(tmp_ctx); return NT_STATUS_OK; } /* a record store inside a transaction */ static NTSTATUS db_ctdb_store_transaction(struct db_record *rec, TDB_DATA data, int flag) { struct db_ctdb_transaction_handle *h = talloc_get_type_abort( rec->private_data, struct db_ctdb_transaction_handle); NTSTATUS status; status = db_ctdb_transaction_store(h, rec->key, data); return status; } /* a record delete inside a transaction */ static NTSTATUS db_ctdb_delete_transaction(struct db_record *rec) { struct db_ctdb_transaction_handle *h = talloc_get_type_abort( rec->private_data, struct db_ctdb_transaction_handle); NTSTATUS status; status = db_ctdb_transaction_store(h, rec->key, tdb_null); return status; } /** * Fetch the db sequence number of a persistent db directly from the db. */ static NTSTATUS db_ctdb_fetch_db_seqnum_from_db(struct db_ctdb_ctx *db, uint64_t *seqnum) { NTSTATUS status; const char *keyname = CTDB_DB_SEQNUM_KEY; TDB_DATA key; TDB_DATA data; struct ctdb_ltdb_header header; TALLOC_CTX *mem_ctx = talloc_stackframe(); if (seqnum == NULL) { return NT_STATUS_INVALID_PARAMETER; } key = string_term_tdb_data(keyname); status = db_ctdb_ltdb_fetch(db, key, &header, mem_ctx, &data); if (!NT_STATUS_IS_OK(status) && !NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) { goto done; } status = NT_STATUS_OK; if (data.dsize != sizeof(uint64_t)) { *seqnum = 0; goto done; } *seqnum = *(uint64_t *)data.dptr; done: TALLOC_FREE(mem_ctx); return status; } /** * Store the database sequence number inside a transaction. */ static NTSTATUS db_ctdb_store_db_seqnum(struct db_ctdb_transaction_handle *h, uint64_t seqnum) { NTSTATUS status; const char *keyname = CTDB_DB_SEQNUM_KEY; TDB_DATA key; TDB_DATA data; key = string_term_tdb_data(keyname); data.dptr = (uint8_t *)&seqnum; data.dsize = sizeof(uint64_t); status = db_ctdb_transaction_store(h, key, data); return status; } /* commit a transaction */ static int db_ctdb_transaction_commit(struct db_context *db) { struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); NTSTATUS rets; int status; struct db_ctdb_transaction_handle *h = ctx->transaction; uint64_t old_seqnum, new_seqnum; int ret; if (h == NULL) { DEBUG(0,(__location__ " transaction commit with no open transaction on db 0x%08x\n", ctx->db_id)); return -1; } if (h->nested_cancel) { db->transaction_cancel(db); DEBUG(5,(__location__ " Failed transaction commit after nested cancel\n")); return -1; } if (h->nesting != 0) { h->nesting--; return 0; } if (h->m_write == NULL) { /* * No changes were made, so don't change the seqnum, * don't push to other node, just exit with success. */ ret = 0; goto done; } DEBUG(5,(__location__ " Commit transaction on db 0x%08x\n", ctx->db_id)); /* * As the last db action before committing, bump the database sequence * number. Note that this undoes all changes to the seqnum records * performed under the transaction. This record is not meant to be * modified by user interaction. It is for internal use only... */ rets = db_ctdb_fetch_db_seqnum_from_db(ctx, &old_seqnum); if (!NT_STATUS_IS_OK(rets)) { DEBUG(1, (__location__ " failed to fetch the db sequence number " "in transaction commit on db 0x%08x\n", ctx->db_id)); ret = -1; goto done; } new_seqnum = old_seqnum + 1; rets = db_ctdb_store_db_seqnum(h, new_seqnum); if (!NT_STATUS_IS_OK(rets)) { DEBUG(1, (__location__ "failed to store the db sequence number " " in transaction commit on db 0x%08x\n", ctx->db_id)); ret = -1; goto done; } again: /* tell ctdbd to commit to the other nodes */ rets = ctdbd_control_local(messaging_ctdbd_connection(procid_self()), CTDB_CONTROL_TRANS3_COMMIT, h->ctx->db_id, 0, db_ctdb_marshall_finish(h->m_write), NULL, NULL, &status); if (!NT_STATUS_IS_OK(rets) || status != 0) { /* * The TRANS3_COMMIT control should only possibly fail when a * recovery has been running concurrently. In any case, the db * will be the same on all nodes, either the new copy or the * old copy. This can be detected by comparing the old and new * local sequence numbers. */ rets = db_ctdb_fetch_db_seqnum_from_db(ctx, &new_seqnum); if (!NT_STATUS_IS_OK(rets)) { DEBUG(1, (__location__ " failed to refetch db sequence " "number after failed TRANS3_COMMIT\n")); ret = -1; goto done; } if (new_seqnum == old_seqnum) { /* Recovery prevented all our changes: retry. */ goto again; } else if (new_seqnum != (old_seqnum + 1)) { DEBUG(0, (__location__ " ERROR: new_seqnum[%lu] != " "old_seqnum[%lu] + (0 or 1) after failed " "TRANS3_COMMIT - this should not happen!\n", (unsigned long)new_seqnum, (unsigned long)old_seqnum)); ret = -1; goto done; } /* * Recovery propagated our changes to all nodes, completing * our commit for us - succeed. */ } ret = 0; done: h->ctx->transaction = NULL; talloc_free(h); return ret; } /* cancel a transaction */ static int db_ctdb_transaction_cancel(struct db_context *db) { struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); struct db_ctdb_transaction_handle *h = ctx->transaction; if (h == NULL) { DEBUG(0,(__location__ " transaction cancel with no open transaction on db 0x%08x\n", ctx->db_id)); return -1; } if (h->nesting != 0) { h->nesting--; h->nested_cancel = true; return 0; } DEBUG(5,(__location__ " Cancel transaction on db 0x%08x\n", ctx->db_id)); ctx->transaction = NULL; talloc_free(h); return 0; } static NTSTATUS db_ctdb_store(struct db_record *rec, TDB_DATA data, int flag) { struct db_ctdb_rec *crec = talloc_get_type_abort( rec->private_data, struct db_ctdb_rec); return db_ctdb_ltdb_store(crec->ctdb_ctx, rec->key, &(crec->header), data); } static NTSTATUS db_ctdb_delete(struct db_record *rec) { TDB_DATA data; /* * We have to store the header with empty data. TODO: Fix the * tdb-level cleanup */ ZERO_STRUCT(data); return db_ctdb_store(rec, data, 0); } static int db_ctdb_record_destr(struct db_record* data) { struct db_ctdb_rec *crec = talloc_get_type_abort( data->private_data, struct db_ctdb_rec); int threshold; DEBUG(10, (DEBUGLEVEL > 10 ? "Unlocking db %u key %s\n" : "Unlocking db %u key %.20s\n", (int)crec->ctdb_ctx->db_id, hex_encode_talloc(data, (unsigned char *)data->key.dptr, data->key.dsize))); if (tdb_chainunlock(crec->ctdb_ctx->wtdb->tdb, data->key) != 0) { DEBUG(0, ("tdb_chainunlock failed\n")); return -1; } threshold = lp_ctdb_locktime_warn_threshold(); if (threshold != 0) { double timediff = timeval_elapsed(&crec->lock_time); if ((timediff * 1000) > threshold) { DEBUG(0, ("Held tdb lock %f seconds\n", timediff)); } } return 0; } static struct db_record *fetch_locked_internal(struct db_ctdb_ctx *ctx, TALLOC_CTX *mem_ctx, TDB_DATA key) { struct db_record *result; struct db_ctdb_rec *crec; NTSTATUS status; TDB_DATA ctdb_data; int migrate_attempts = 0; if (!(result = talloc(mem_ctx, struct db_record))) { DEBUG(0, ("talloc failed\n")); return NULL; } if (!(crec = TALLOC_ZERO_P(result, struct db_ctdb_rec))) { DEBUG(0, ("talloc failed\n")); TALLOC_FREE(result); return NULL; } result->private_data = (void *)crec; crec->ctdb_ctx = ctx; result->key.dsize = key.dsize; result->key.dptr = (uint8 *)talloc_memdup(result, key.dptr, key.dsize); if (result->key.dptr == NULL) { DEBUG(0, ("talloc failed\n")); TALLOC_FREE(result); return NULL; } /* * Do a blocking lock on the record */ again: if (DEBUGLEVEL >= 10) { char *keystr = hex_encode_talloc(result, key.dptr, key.dsize); DEBUG(10, (DEBUGLEVEL > 10 ? "Locking db %u key %s\n" : "Locking db %u key %.20s\n", (int)crec->ctdb_ctx->db_id, keystr)); TALLOC_FREE(keystr); } if (tdb_chainlock(ctx->wtdb->tdb, key) != 0) { DEBUG(3, ("tdb_chainlock failed\n")); TALLOC_FREE(result); return NULL; } result->store = db_ctdb_store; result->delete_rec = db_ctdb_delete; talloc_set_destructor(result, db_ctdb_record_destr); ctdb_data = tdb_fetch(ctx->wtdb->tdb, key); /* * See if we have a valid record and we are the dmaster. If so, we can * take the shortcut and just return it. */ if ((ctdb_data.dptr == NULL) || (ctdb_data.dsize < sizeof(struct ctdb_ltdb_header)) || ((struct ctdb_ltdb_header *)ctdb_data.dptr)->dmaster != get_my_vnn() #if 0 || (random() % 2 != 0) #endif ) { SAFE_FREE(ctdb_data.dptr); tdb_chainunlock(ctx->wtdb->tdb, key); talloc_set_destructor(result, NULL); migrate_attempts += 1; DEBUG(10, ("ctdb_data.dptr = %p, dmaster = %u (%u)\n", ctdb_data.dptr, ctdb_data.dptr ? ((struct ctdb_ltdb_header *)ctdb_data.dptr)->dmaster : -1, get_my_vnn())); status = ctdbd_migrate( messaging_ctdbd_connection(procid_self()), ctx->db_id, key); if (!NT_STATUS_IS_OK(status)) { DEBUG(5, ("ctdb_migrate failed: %s\n", nt_errstr(status))); TALLOC_FREE(result); return NULL; } /* now its migrated, try again */ goto again; } if (migrate_attempts > 10) { DEBUG(0, ("db_ctdb_fetch_locked needed %d attempts\n", migrate_attempts)); } GetTimeOfDay(&crec->lock_time); memcpy(&crec->header, ctdb_data.dptr, sizeof(crec->header)); result->value.dsize = ctdb_data.dsize - sizeof(crec->header); result->value.dptr = NULL; if ((result->value.dsize != 0) && !(result->value.dptr = (uint8 *)talloc_memdup( result, ctdb_data.dptr + sizeof(crec->header), result->value.dsize))) { DEBUG(0, ("talloc failed\n")); TALLOC_FREE(result); } SAFE_FREE(ctdb_data.dptr); return result; } static struct db_record *db_ctdb_fetch_locked(struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key) { struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); if (ctx->transaction != NULL) { return db_ctdb_fetch_locked_transaction(ctx, mem_ctx, key); } if (db->persistent) { return db_ctdb_fetch_locked_persistent(ctx, mem_ctx, key); } return fetch_locked_internal(ctx, mem_ctx, key); } /* fetch (unlocked, no migration) operation on ctdb */ static int db_ctdb_fetch(struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key, TDB_DATA *data) { struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); NTSTATUS status; TDB_DATA ctdb_data; if (ctx->transaction) { return db_ctdb_transaction_fetch(ctx, mem_ctx, key, data); } /* try a direct fetch */ ctdb_data = tdb_fetch(ctx->wtdb->tdb, key); /* * See if we have a valid record and we are the dmaster. If so, we can * take the shortcut and just return it. * we bypass the dmaster check for persistent databases */ if ((ctdb_data.dptr != NULL) && (ctdb_data.dsize >= sizeof(struct ctdb_ltdb_header)) && (db->persistent || ((struct ctdb_ltdb_header *)ctdb_data.dptr)->dmaster == get_my_vnn())) { /* we are the dmaster - avoid the ctdb protocol op */ data->dsize = ctdb_data.dsize - sizeof(struct ctdb_ltdb_header); if (data->dsize == 0) { SAFE_FREE(ctdb_data.dptr); data->dptr = NULL; return 0; } data->dptr = (uint8 *)talloc_memdup( mem_ctx, ctdb_data.dptr+sizeof(struct ctdb_ltdb_header), data->dsize); SAFE_FREE(ctdb_data.dptr); if (data->dptr == NULL) { return -1; } return 0; } SAFE_FREE(ctdb_data.dptr); /* we weren't able to get it locally - ask ctdb to fetch it for us */ status = ctdbd_fetch(messaging_ctdbd_connection(procid_self()), ctx->db_id, key, mem_ctx, data); if (!NT_STATUS_IS_OK(status)) { DEBUG(5, ("ctdbd_fetch failed: %s\n", nt_errstr(status))); return -1; } return 0; } struct traverse_state { struct db_context *db; int (*fn)(struct db_record *rec, void *private_data); void *private_data; }; static void traverse_callback(TDB_DATA key, TDB_DATA data, void *private_data) { struct traverse_state *state = (struct traverse_state *)private_data; struct db_record *rec; TALLOC_CTX *tmp_ctx = talloc_new(state->db); /* we have to give them a locked record to prevent races */ rec = db_ctdb_fetch_locked(state->db, tmp_ctx, key); if (rec && rec->value.dsize > 0) { state->fn(rec, state->private_data); } talloc_free(tmp_ctx); } static int traverse_persistent_callback(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *private_data) { struct traverse_state *state = (struct traverse_state *)private_data; struct db_record *rec; TALLOC_CTX *tmp_ctx = talloc_new(state->db); int ret = 0; /* we have to give them a locked record to prevent races */ rec = db_ctdb_fetch_locked(state->db, tmp_ctx, kbuf); if (rec && rec->value.dsize > 0) { ret = state->fn(rec, state->private_data); } talloc_free(tmp_ctx); return ret; } static int db_ctdb_traverse(struct db_context *db, int (*fn)(struct db_record *rec, void *private_data), void *private_data) { struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); struct traverse_state state; state.db = db; state.fn = fn; state.private_data = private_data; if (db->persistent) { /* for persistent databases we don't need to do a ctdb traverse, we can do a faster local traverse */ return tdb_traverse(ctx->wtdb->tdb, traverse_persistent_callback, &state); } ctdbd_traverse(ctx->db_id, traverse_callback, &state); return 0; } static NTSTATUS db_ctdb_store_deny(struct db_record *rec, TDB_DATA data, int flag) { return NT_STATUS_MEDIA_WRITE_PROTECTED; } static NTSTATUS db_ctdb_delete_deny(struct db_record *rec) { return NT_STATUS_MEDIA_WRITE_PROTECTED; } static void traverse_read_callback(TDB_DATA key, TDB_DATA data, void *private_data) { struct traverse_state *state = (struct traverse_state *)private_data; struct db_record rec; rec.key = key; rec.value = data; rec.store = db_ctdb_store_deny; rec.delete_rec = db_ctdb_delete_deny; rec.private_data = state->db; state->fn(&rec, state->private_data); } static int traverse_persistent_callback_read(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *private_data) { struct traverse_state *state = (struct traverse_state *)private_data; struct db_record rec; rec.key = kbuf; rec.value = dbuf; rec.store = db_ctdb_store_deny; rec.delete_rec = db_ctdb_delete_deny; rec.private_data = state->db; if (rec.value.dsize <= sizeof(struct ctdb_ltdb_header)) { /* a deleted record */ return 0; } rec.value.dsize -= sizeof(struct ctdb_ltdb_header); rec.value.dptr += sizeof(struct ctdb_ltdb_header); return state->fn(&rec, state->private_data); } static int db_ctdb_traverse_read(struct db_context *db, int (*fn)(struct db_record *rec, void *private_data), void *private_data) { struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); struct traverse_state state; state.db = db; state.fn = fn; state.private_data = private_data; if (db->persistent) { /* for persistent databases we don't need to do a ctdb traverse, we can do a faster local traverse */ return tdb_traverse_read(ctx->wtdb->tdb, traverse_persistent_callback_read, &state); } ctdbd_traverse(ctx->db_id, traverse_read_callback, &state); return 0; } static int db_ctdb_get_seqnum(struct db_context *db) { struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); return tdb_get_seqnum(ctx->wtdb->tdb); } static int db_ctdb_get_flags(struct db_context *db) { struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data, struct db_ctdb_ctx); return tdb_get_flags(ctx->wtdb->tdb); } struct db_context *db_open_ctdb(TALLOC_CTX *mem_ctx, const char *name, int hash_size, int tdb_flags, int open_flags, mode_t mode) { struct db_context *result; struct db_ctdb_ctx *db_ctdb; char *db_path; struct ctdbd_connection *conn; if (!lp_clustering()) { DEBUG(10, ("Clustering disabled -- no ctdb\n")); return NULL; } if (!(result = TALLOC_ZERO_P(mem_ctx, struct db_context))) { DEBUG(0, ("talloc failed\n")); TALLOC_FREE(result); return NULL; } if (!(db_ctdb = TALLOC_P(result, struct db_ctdb_ctx))) { DEBUG(0, ("talloc failed\n")); TALLOC_FREE(result); return NULL; } db_ctdb->transaction = NULL; db_ctdb->db = result; conn = messaging_ctdbd_connection(procid_self()); if (!NT_STATUS_IS_OK(ctdbd_db_attach(conn, name, &db_ctdb->db_id, tdb_flags))) { DEBUG(0, ("ctdbd_db_attach failed for %s\n", name)); TALLOC_FREE(result); return NULL; } db_path = ctdbd_dbpath(conn, db_ctdb, db_ctdb->db_id); result->persistent = ((tdb_flags & TDB_CLEAR_IF_FIRST) == 0); /* only pass through specific flags */ tdb_flags &= TDB_SEQNUM; /* honor permissions if user has specified O_CREAT */ if (open_flags & O_CREAT) { chmod(db_path, mode); } db_ctdb->wtdb = tdb_wrap_open(db_ctdb, db_path, hash_size, tdb_flags, O_RDWR, 0); if (db_ctdb->wtdb == NULL) { DEBUG(0, ("Could not open tdb %s: %s\n", db_path, strerror(errno))); TALLOC_FREE(result); return NULL; } talloc_free(db_path); if (result->persistent) { db_ctdb->lock_ctx = g_lock_ctx_init(db_ctdb, ctdb_conn_msg_ctx(conn)); if (db_ctdb->lock_ctx == NULL) { DEBUG(0, ("g_lock_ctx_init failed\n")); TALLOC_FREE(result); return NULL; } } result->private_data = (void *)db_ctdb; result->fetch_locked = db_ctdb_fetch_locked; result->fetch = db_ctdb_fetch; result->traverse = db_ctdb_traverse; result->traverse_read = db_ctdb_traverse_read; result->get_seqnum = db_ctdb_get_seqnum; result->get_flags = db_ctdb_get_flags; result->transaction_start = db_ctdb_transaction_start; result->transaction_commit = db_ctdb_transaction_commit; result->transaction_cancel = db_ctdb_transaction_cancel; DEBUG(3,("db_open_ctdb: opened database '%s' with dbid 0x%x\n", name, db_ctdb->db_id)); return result; } #endif