/* Unix SMB/CIFS implementation. Database interface wrapper around ctdbd Copyright (C) Volker Lendecke 2007 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" struct db_ctdb_ctx { struct tdb_wrap *wtdb; uint32 db_id; }; struct db_ctdb_rec { struct db_ctdb_ctx *ctdb_ctx; struct ctdb_ltdb_header header; }; 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); TDB_DATA cdata; int ret; cdata.dsize = sizeof(crec->header) + data.dsize; if (!(cdata.dptr = SMB_MALLOC_ARRAY(uint8, cdata.dsize))) { return NT_STATUS_NO_MEMORY; } memcpy(cdata.dptr, &crec->header, sizeof(crec->header)); memcpy(cdata.dptr + sizeof(crec->header), data.dptr, data.dsize); ret = tdb_store(crec->ctdb_ctx->wtdb->tdb, rec->key, cdata, TDB_REPLACE); SAFE_FREE(cdata.dptr); return (ret == 0) ? NT_STATUS_OK : NT_STATUS_INTERNAL_DB_CORRUPTION; } /* for persistent databases the store is a bit different. We have to ask the ctdb daemon to push the record to all nodes after the store */ static NTSTATUS db_ctdb_store_persistent(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); TDB_DATA cdata; int ret; NTSTATUS status; cdata.dsize = sizeof(crec->header) + data.dsize; if (!(cdata.dptr = SMB_MALLOC_ARRAY(uint8, cdata.dsize))) { return NT_STATUS_NO_MEMORY; } crec->header.rsn++; memcpy(cdata.dptr, &crec->header, sizeof(crec->header)); memcpy(cdata.dptr + sizeof(crec->header), data.dptr, data.dsize); ret = tdb_store(crec->ctdb_ctx->wtdb->tdb, rec->key, cdata, TDB_REPLACE); status = (ret == 0) ? NT_STATUS_OK : NT_STATUS_INTERNAL_DB_CORRUPTION; /* now tell ctdbd to update this record on all other nodes */ if (NT_STATUS_IS_OK(status)) { status = ctdbd_persistent_store(messaging_ctdbd_connection(), crec->ctdb_ctx->db_id, rec->key, cdata); } SAFE_FREE(cdata.dptr); return status; } static NTSTATUS db_ctdb_delete(struct db_record *rec) { struct db_ctdb_rec *crec = talloc_get_type_abort( rec->private_data, struct db_ctdb_rec); TDB_DATA data; int ret; /* * We have to store the header with empty data. TODO: Fix the * tdb-level cleanup */ data.dptr = (uint8 *)&crec->header; data.dsize = sizeof(crec->header); ret = tdb_store(crec->ctdb_ctx->wtdb->tdb, rec->key, data, TDB_REPLACE); return (ret == 0) ? NT_STATUS_OK : NT_STATUS_INTERNAL_DB_CORRUPTION; } 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); DEBUG(10, (DEBUGLEVEL > 10 ? "Unlocking db %u key %s\n" : "Unlocking db %u key %.20s\n", (int)crec->ctdb_ctx->db_id, hex_encode(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; } return 0; } 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); 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(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; } if (db->persistent) { result->store = db_ctdb_store_persistent; } else { 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(),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)); } 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; } /* 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; /* 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(),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); } 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; 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; } if (!NT_STATUS_IS_OK(ctdbd_db_attach(messaging_ctdbd_connection(),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(messaging_ctdbd_connection(), db_ctdb, db_ctdb->db_id); result->persistent = ((tdb_flags & TDB_CLEAR_IF_FIRST) == 0); /* only pass through specific flags */ tdb_flags &= TDB_SEQNUM; 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); 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; DEBUG(3,("db_open_ctdb: opened database '%s' with dbid 0x%x\n", name, db_ctdb->db_id)); return result; } #endif