#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;
- bool in_replay;
/*
* we store the reads and writes done under a transaction:
* - one list stores both reads and writes (m_all),
struct ctdb_marshall_buffer *m_write;
uint32_t nesting;
bool nested_cancel;
+ char *lock_name;
};
struct db_ctdb_ctx {
struct tdb_wrap *wtdb;
uint32 db_id;
struct db_ctdb_transaction_handle *transaction;
+ struct g_lock_ctx *lock_ctx;
};
struct db_ctdb_rec {
return r;
}
-
-static int32_t db_ctdb_transaction_active(uint32_t db_id)
-{
- int32_t status;
- NTSTATUS ret;
- TDB_DATA indata;
-
- indata.dptr = (uint8_t *)&db_id;
- indata.dsize = sizeof(db_id);
-
- ret = ctdbd_control_local(messaging_ctdbd_connection(),
- CTDB_CONTROL_TRANS2_ACTIVE, 0, 0,
- indata, NULL, NULL, &status);
-
- if (!NT_STATUS_IS_OK(ret)) {
- DEBUG(2, ("ctdb control TRANS2_ACTIVE failed\n"));
- return -1;
- }
-
- return status;
-}
-
-
/**
* CTDB transaction destructor
*/
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 ctdb database:
- * - lock the transaction lock key
- * - start the tdb transaction
- */
-static int db_ctdb_transaction_fetch_start(struct db_ctdb_transaction_handle *h)
-{
- struct db_record *rh;
- struct db_ctdb_rec *crec;
- 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;
- pid_t pid;
NTSTATUS status;
- struct ctdb_ltdb_header header;
- int32_t transaction_status;
- 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;
- }
- crec = talloc_get_type_abort(rh->private_data, struct db_ctdb_rec);
-
- transaction_status = db_ctdb_transaction_active(ctx->db_id);
- if (transaction_status == 1) {
- unsigned long int usec = (1000 + random()) % 100000;
- DEBUG(3, ("Transaction already active on db_id[0x%08x]."
- "Re-trying after %lu microseconds...",
- ctx->db_id, usec));
- talloc_free(tmp_ctx);
- usleep(usec);
- goto again;
- }
-
- /*
- * store the pid in the database:
- * it is not enought that the node is dmaster...
- */
- pid = getpid();
- data.dptr = (unsigned char *)&pid;
- data.dsize = sizeof(pid_t);
- crec->header.rsn++;
- crec->header.dmaster = get_my_vnn();
- status = db_ctdb_ltdb_store(ctx, key, &(crec->header), data);
+ status = g_lock_unlock(h->ctx->lock_ctx, h->lock_name);
if (!NT_STATUS_IS_OK(status)) {
- DEBUG(0, (__location__ " Failed to store pid in transaction "
- "record: %s\n", nt_errstr(status)));
- talloc_free(tmp_ctx);
+ DEBUG(0, ("g_lock_unlock failed: %s\n", nt_errstr(status)));
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;
- }
-
- status = db_ctdb_ltdb_fetch(ctx, key, &header, tmp_ctx, &data);
- if (!NT_STATUS_IS_OK(status)) {
- DEBUG(0, (__location__ " failed to refetch transaction lock "
- "record inside transaction: %s - retrying\n",
- nt_errstr(status)));
- tdb_transaction_cancel(ctx->wtdb->tdb);
- talloc_free(tmp_ctx);
- goto again;
- }
-
- if (header.dmaster != get_my_vnn()) {
- DEBUG(3, (__location__ " refetch transaction lock record : "
- "we are not dmaster any more "
- "(dmaster[%u] != my_vnn[%u]) - retrying\n",
- header.dmaster, get_my_vnn()));
- tdb_transaction_cancel(ctx->wtdb->tdb);
- talloc_free(tmp_ctx);
- goto again;
- }
-
- if ((data.dsize != sizeof(pid_t)) || (*(pid_t *)(data.dptr) != pid)) {
- DEBUG(3, (__location__ " refetch transaction lock record: "
- "another local process has started a transaction "
- "(stored pid [%u] != my pid [%u]) - retrying\n",
- *(pid_t *)(data.dptr), pid));
- tdb_transaction_cancel(ctx->wtdb->tdb);
- talloc_free(tmp_ctx);
- goto again;
- }
-
- talloc_free(tmp_ctx);
-
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;
- int ret;
+ NTSTATUS status;
struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
struct db_ctdb_ctx);
h->ctx = ctx;
- ret = db_ctdb_transaction_fetch_start(h);
- if (ret != 0) {
- talloc_free(h);
+ 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;
}
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;
+ TDB_DATA data;
+ int i;
+
+ if (buf == NULL) {
+ return false;
+ }
+
+ /*
+ * 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;
+
+ rec = db_ctdb_marshall_loop_next(buf, rec, &reqid, &h, &tkey,
+ &tdata);
+ if (rec == NULL) {
+ return false;
+ }
+
+ if (tdb_data_equal(key, tkey)) {
+ found = true;
+ data = tdata;
+ }
+ }
+
+ 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
{
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);
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;
- }
+ 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;
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 */
TDB_DATA key, TDB_DATA data)
{
TALLOC_CTX *tmp_ctx = talloc_new(h);
- int ret;
TDB_DATA rec;
struct ctdb_ltdb_header header;
- NTSTATUS status;
+
+ ZERO_STRUCT(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);
- } 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;
+
+ 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 0;
+ }
}
SAFE_FREE(rec.dptr);
}
header.dmaster = get_my_vnn();
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_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);
return -1;
}
- status = db_ctdb_ltdb_store(h->ctx, key, &header, data);
- if (NT_STATUS_IS_OK(status)) {
- ret = 0;
- } else {
- ret = -1;
- }
-
talloc_free(tmp_ctx);
-
- return ret;
+ return 0;
}
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
*/
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));
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;
+ goto done;
}
/* 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,
+ rets = ctdbd_control_local(messaging_ctdbd_connection(),
+ CTDB_CONTROL_TRANS3_COMMIT,
h->ctx->db_id, 0,
- db_ctdb_marshall_finish(h->m_write), NULL, NULL, &status);
+ 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 == 100) {
- 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;
- }
+ /*
+ * TODO:
+ * check the database sequence number and
+ * compare it to the seqnum after applying the
+ * marshall buffer. If it is the same: return success.
+ */
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);
+done:
h->ctx->transaction = NULL;
talloc_free(h);
return 0;
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"));
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))) {
+ conn = messaging_ctdbd_connection();
+
+ 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(messaging_ctdbd_connection(), db_ctdb, db_ctdb->db_id);
+ db_path = ctdbd_dbpath(conn, db_ctdb, db_ctdb->db_id);
result->persistent = ((tdb_flags & TDB_CLEAR_IF_FIRST) == 0);
}
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;
git.samba.org / samba.git / commitdiff