diff options
Diffstat (limited to 'source3/lib/dbwrap_ctdb.c')
| -rw-r--r-- | source3/lib/dbwrap_ctdb.c | 1223 |
1 files changed, 1223 insertions, 0 deletions
diff --git a/source3/lib/dbwrap_ctdb.c b/source3/lib/dbwrap_ctdb.c new file mode 100644 index 0000000000..63a5ce4de6 --- /dev/null +++ b/source3/lib/dbwrap_ctdb.c @@ -0,0 +1,1223 @@ +/* + 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_transaction_handle { + struct db_ctdb_ctx *ctx; + bool in_replay; + /* we store the reads and writes done under a transaction one + list stores both reads and writes, the other just writes + */ + struct ctdb_marshall_buffer *m_all; + struct ctdb_marshall_buffer *m_write; + uint32_t nesting; + bool nested_cancel; +}; + +struct db_ctdb_ctx { + struct db_context *db; + struct tdb_wrap *wtdb; + uint32 db_id; + struct db_ctdb_transaction_handle *transaction; +}; + +struct db_ctdb_rec { + struct db_ctdb_ctx *ctdb_ctx; + struct ctdb_ltdb_header header; +}; + +static struct db_record *fetch_locked_internal(struct db_ctdb_ctx *ctx, + TALLOC_CTX *mem_ctx, + TDB_DATA key, + bool persistent); + +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; +} + + + +/* + 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; + + r = db_ctdb_marshall_record(mem_ctx, 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) { + return NULL; + } + 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); + return NULL; + } + + memcpy(m_size + (uint8_t *)m2, r, r_size); + + talloc_free(r); + + m2->count++; + + 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; +} + + + +/* start a transaction on a database */ +static int db_ctdb_transaction_destructor(struct db_ctdb_transaction_handle *h) +{ + tdb_transaction_cancel(h->ctx->wtdb->tdb); + return 0; +} + +/* start a transaction on a database */ +static int db_ctdb_transaction_fetch_start(struct db_ctdb_transaction_handle *h) +{ + struct db_record *rh; + TDB_DATA key; + TALLOC_CTX *tmp_ctx; + const char *keyname = CTDB_TRANSACTION_LOCK_KEY; + int ret; + struct db_ctdb_ctx *ctx = h->ctx; + TDB_DATA data; + + key.dptr = (uint8_t *)discard_const(keyname); + key.dsize = strlen(keyname); + +again: + tmp_ctx = talloc_new(h); + + rh = fetch_locked_internal(ctx, tmp_ctx, key, true); + if (rh == NULL) { + DEBUG(0,(__location__ " Failed to fetch_lock database\n")); + talloc_free(tmp_ctx); + return -1; + } + talloc_free(rh); + + ret = tdb_transaction_start(ctx->wtdb->tdb); + if (ret != 0) { + DEBUG(0,(__location__ " Failed to start tdb transaction\n")); + talloc_free(tmp_ctx); + return -1; + } + + data = tdb_fetch(ctx->wtdb->tdb, key); + if ((data.dptr == NULL) || + (data.dsize < sizeof(struct ctdb_ltdb_header)) || + ((struct ctdb_ltdb_header *)data.dptr)->dmaster != get_my_vnn()) { + SAFE_FREE(data.dptr); + tdb_transaction_cancel(ctx->wtdb->tdb); + talloc_free(tmp_ctx); + goto again; + } + + SAFE_FREE(data.dptr); + talloc_free(tmp_ctx); + + return 0; +} + + +/* start a transaction on a database */ +static int db_ctdb_transaction_start(struct db_context *db) +{ + struct db_ctdb_transaction_handle *h; + int ret; + 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; + + ret = db_ctdb_transaction_fetch_start(h); + if (ret != 0) { + 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; +} + + + +/* + 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; + + *data = tdb_fetch(h->ctx->wtdb->tdb, key); + + if (data->dptr != NULL) { + uint8_t *oldptr = (uint8_t *)data->dptr; + data->dsize -= sizeof(struct ctdb_ltdb_header); + if (data->dsize == 0) { + data->dptr = NULL; + } else { + data->dptr = (uint8 *) + talloc_memdup( + mem_ctx, data->dptr+sizeof(struct ctdb_ltdb_header), + data->dsize); + } + SAFE_FREE(oldptr); + if (data->dptr == NULL && data->dsize != 0) { + return -1; + } + } + + if (!h->in_replay) { + 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; + + 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 *rec) +{ + 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; + + 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 */ + talloc_set_destructor((struct db_record *)talloc_new(rec), db_ctdb_record_destructor); + return rec; +} + + +/* + stores a record inside a transaction + */ +static int db_ctdb_transaction_store(struct db_ctdb_transaction_handle *h, + TDB_DATA key, TDB_DATA data) +{ + TALLOC_CTX *tmp_ctx = talloc_new(h); + int ret; + TDB_DATA rec; + struct ctdb_ltdb_header header; + + /* we need the header so we can update the RSN */ + rec = tdb_fetch(h->ctx->wtdb->tdb, key); + if (rec.dptr == NULL) { + /* the record doesn't exist - create one with us as dmaster. + This is only safe because we are in a transaction and this + is a persistent database */ + ZERO_STRUCT(header); + header.dmaster = get_my_vnn(); + } else { + 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 0; + } + SAFE_FREE(rec.dptr); + } + + header.rsn++; + + if (!h->in_replay) { + 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 -1; + } + } + + 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 -1; + } + + rec.dsize = data.dsize + sizeof(struct ctdb_ltdb_header); + rec.dptr = (uint8_t *)talloc_size(tmp_ctx, rec.dsize); + if (rec.dptr == NULL) { + DEBUG(0,(__location__ " Failed to alloc record\n")); + talloc_free(tmp_ctx); + return -1; + } + 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(h->ctx->wtdb->tdb, key, rec, TDB_REPLACE); + + talloc_free(tmp_ctx); + + return ret; +} + + +/* + 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); + int ret; + + ret = db_ctdb_transaction_store(h, rec->key, data); + if (ret != 0) { + return tdb_error_to_ntstatus(h->ctx->wtdb->tdb); + } + return NT_STATUS_OK; +} + +/* + 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); + int ret; + + ret = db_ctdb_transaction_store(h, rec->key, tdb_null); + if (ret != 0) { + return tdb_error_to_ntstatus(h->ctx->wtdb->tdb); + } + return NT_STATUS_OK; +} + + +/* + replay a transaction + */ +static int ctdb_replay_transaction(struct db_ctdb_transaction_handle *h) +{ + int ret, i; + struct ctdb_rec_data *rec = NULL; + + h->in_replay = true; + talloc_free(h->m_write); + h->m_write = NULL; + + ret = db_ctdb_transaction_fetch_start(h); + if (ret != 0) { + return ret; + } + + for (i=0;i<h->m_all->count;i++) { + TDB_DATA key, data; + + rec = db_ctdb_marshall_loop_next(h->m_all, rec, NULL, NULL, &key, &data); + if (rec == NULL) { + DEBUG(0, (__location__ " Out of records in ctdb_replay_transaction?\n")); + goto failed; + } + + if (rec->reqid == 0) { + /* its a store */ + if (db_ctdb_transaction_store(h, key, data) != 0) { + goto failed; + } + } else { + TDB_DATA data2; + TALLOC_CTX *tmp_ctx = talloc_new(h); + + if (db_ctdb_transaction_fetch(h->ctx, tmp_ctx, key, &data2) != 0) { + talloc_free(tmp_ctx); + goto failed; + } + if (data2.dsize != data.dsize || + memcmp(data2.dptr, data.dptr, data.dsize) != 0) { + /* the record has changed on us - we have to give up */ + talloc_free(tmp_ctx); + goto failed; + } + talloc_free(tmp_ctx); + } + } + + return 0; + +failed: + tdb_transaction_cancel(h->ctx->wtdb->tdb); + return -1; +} + + +/* + 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 ret; + int status; + int retries = 0; + struct db_ctdb_transaction_handle *h = ctx->transaction; + enum ctdb_controls failure_control = CTDB_CONTROL_TRANS2_ERROR; + + 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; + } + + DEBUG(5,(__location__ " Commit transaction on db 0x%08x\n", ctx->db_id)); + + talloc_set_destructor(h, NULL); + + /* our commit strategy is quite complex. + + - we first try to commit the changes to all other nodes + + - if that works, then we commit locally and we are done + + - if a commit on another node fails, then we need to cancel + the transaction, then restart the transaction (thus + opening a window of time for a pending recovery to + complete), then replay the transaction, checking all the + reads and writes (checking that reads give the same data, + and writes succeed). Then we retry the transaction to the + other nodes + */ + +again: + if (h->m_write == NULL) { + /* no changes were made, potentially after a retry */ + tdb_transaction_cancel(h->ctx->wtdb->tdb); + talloc_free(h); + ctx->transaction = NULL; + return 0; + } + + /* tell ctdbd to commit to the other nodes */ + rets = ctdbd_control_local(messaging_ctdbd_connection(), + retries==0?CTDB_CONTROL_TRANS2_COMMIT:CTDB_CONTROL_TRANS2_COMMIT_RETRY, + h->ctx->db_id, 0, + db_ctdb_marshall_finish(h->m_write), NULL, NULL, &status); + if (!NT_STATUS_IS_OK(rets) || status != 0) { + tdb_transaction_cancel(h->ctx->wtdb->tdb); + sleep(1); + + if (!NT_STATUS_IS_OK(rets)) { + failure_control = CTDB_CONTROL_TRANS2_ERROR; + } else { + /* work out what error code we will give if we + have to fail the operation */ + switch ((enum ctdb_trans2_commit_error)status) { + case CTDB_TRANS2_COMMIT_SUCCESS: + case CTDB_TRANS2_COMMIT_SOMEFAIL: + case CTDB_TRANS2_COMMIT_TIMEOUT: + failure_control = CTDB_CONTROL_TRANS2_ERROR; + break; + case CTDB_TRANS2_COMMIT_ALLFAIL: + failure_control = CTDB_CONTROL_TRANS2_FINISHED; + break; + } + } + + if (++retries == 5) { + DEBUG(0,(__location__ " Giving up transaction on db 0x%08x after %d retries failure_control=%u\n", + h->ctx->db_id, retries, (unsigned)failure_control)); + ctdbd_control_local(messaging_ctdbd_connection(), failure_control, + h->ctx->db_id, CTDB_CTRL_FLAG_NOREPLY, + tdb_null, NULL, NULL, NULL); + h->ctx->transaction = NULL; + talloc_free(h); + ctx->transaction = NULL; + return -1; + } + + if (ctdb_replay_transaction(h) != 0) { + DEBUG(0,(__location__ " Failed to replay transaction failure_control=%u\n", + (unsigned)failure_control)); + ctdbd_control_local(messaging_ctdbd_connection(), failure_control, + h->ctx->db_id, CTDB_CTRL_FLAG_NOREPLY, + tdb_null, NULL, NULL, NULL); + h->ctx->transaction = NULL; + talloc_free(h); + ctx->transaction = NULL; + return -1; + } + goto again; + } else { + failure_control = CTDB_CONTROL_TRANS2_ERROR; + } + + /* do the real commit locally */ + ret = tdb_transaction_commit(h->ctx->wtdb->tdb); + if (ret != 0) { + DEBUG(0,(__location__ " Failed to commit transaction failure_control=%u\n", + (unsigned)failure_control)); + ctdbd_control_local(messaging_ctdbd_connection(), failure_control, h->ctx->db_id, + CTDB_CTRL_FLAG_NOREPLY, tdb_null, NULL, NULL, NULL); + h->ctx->transaction = NULL; + talloc_free(h); + return ret; + } + + /* tell ctdbd that we are finished with our local commit */ + ctdbd_control_local(messaging_ctdbd_connection(), CTDB_CONTROL_TRANS2_FINISHED, + h->ctx->db_id, CTDB_CTRL_FLAG_NOREPLY, + tdb_null, NULL, NULL, NULL); + h->ctx->transaction = NULL; + talloc_free(h); + return 0; +} + + +/* + 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); + 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 + : tdb_error_to_ntstatus(crec->ctdb_ctx->wtdb->tdb); +} + + + +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); + + 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 *fetch_locked_internal(struct db_ctdb_ctx *ctx, + TALLOC_CTX *mem_ctx, + TDB_DATA key, + bool persistent) +{ + 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; + } + + 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; +} + +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, db->persistent); +} + +/* + 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(),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; + } + + db_ctdb->transaction = NULL; + db_ctdb->db = result; + + 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; + + /* 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); + + 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->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 |