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/>.
*/
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
- */
+ /*
+ * 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;
};
struct db_ctdb_ctx {
}
+/**
+ * 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
*/
{
struct ctdb_rec_data *r;
size_t m_size, r_size;
- struct ctdb_marshall_buffer *m2;
+ struct ctdb_marshall_buffer *m2 = NULL;
- r = db_ctdb_marshall_record(mem_ctx, reqid, key, header, data);
+ r = db_ctdb_marshall_record(talloc_tos(), reqid, key, header, data);
if (r == NULL) {
talloc_free(m);
return NULL;
}
if (m == NULL) {
- m = talloc_zero_size(mem_ctx, offsetof(struct ctdb_marshall_buffer, data));
+ m = (struct ctdb_marshall_buffer *)talloc_zero_size(
+ mem_ctx, offsetof(struct ctdb_marshall_buffer, data));
if (m == NULL) {
- return NULL;
+ goto done;
}
m->db_id = db_id;
}
m_size = talloc_get_size(m);
r_size = talloc_get_size(r);
- m2 = talloc_realloc_size(mem_ctx, m, m_size + r_size);
+ m2 = (struct ctdb_marshall_buffer *)talloc_realloc_size(
+ mem_ctx, m, m_size + r_size);
if (m2 == NULL) {
talloc_free(m);
- return NULL;
+ goto done;
}
memcpy(m_size + (uint8_t *)m2, r, r_size);
- talloc_free(r);
-
m2->count++;
+done:
+ talloc_free(r);
return m2;
}
/*
loop over a marshalling buffer
-
+
- pass r==NULL to start
- loop the number of times indicated by m->count
*/
if (reqid != NULL) {
*reqid = r->reqid;
}
-
+
if (key != NULL) {
key->dptr = &r->data[0];
key->dsize = r->keylen;
}
+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;
+}
+
-/* start a transaction on a database */
+/**
+ * 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 database */
+/**
+ * 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 = discard_const(keyname);
+ key.dptr = (uint8_t *)discard_const(keyname);
key.dsize = strlen(keyname);
again:
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);
+ 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);
+ return -1;
+ }
+
talloc_free(rh);
ret = tdb_transaction_start(ctx->wtdb->tdb);
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);
+ 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;
}
- SAFE_FREE(data.dptr);
talloc_free(tmp_ctx);
return 0;
}
-/* start a transaction on a database */
+/**
+ * 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;
}
if (ctx->transaction) {
- DEBUG(0,("Nested transactions not supported on db 0x%08x\n", ctx->db_id));
- return -1;
+ ctx->transaction->nesting++;
+ return 0;
}
h = talloc_zero(db, struct db_ctdb_transaction_handle);
TDB_DATA key, TDB_DATA *data)
{
struct db_ctdb_transaction_handle *h = db->transaction;
+ NTSTATUS status;
- *data = tdb_fetch(h->ctx->wtdb->tdb, key);
+ status = db_ctdb_ltdb_fetch(h->ctx, key, NULL, mem_ctx, data);
- 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 (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
+ *data = tdb_null;
+ } else if (!NT_STATUS_IS_OK(status)) {
+ return -1;
}
if (!h->in_replay) {
return result;
}
-static int db_ctdb_record_destructor(struct db_record *rec)
+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);
- h->ctx->db->transaction_cancel(h->ctx->db);
+ int ret = h->ctx->db->transaction_commit(h->ctx->db);
+ if (ret != 0) {
+ DEBUG(0,(__location__ " transaction_commit failed\n"));
+ }
return 0;
}
TDB_DATA key)
{
int res;
- struct db_record *rec;
+ struct db_record *rec, **recp;
res = db_ctdb_transaction_start(ctx->db);
if (res == -1) {
}
/* destroy this transaction when we release the lock */
- talloc_set_destructor((struct db_record *)talloc_new(rec), db_ctdb_record_destructor);
+ 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;
}
int ret;
TDB_DATA rec;
struct ctdb_ltdb_header header;
+ NTSTATUS status;
/* we need the header so we can update the RSN */
rec = tdb_fetch(h->ctx->wtdb->tdb, key);
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.dmaster = get_my_vnn();
header.rsn++;
if (!h->in_replay) {
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 = talloc_size(tmp_ctx, rec.dsize);
- if (rec.dptr == NULL) {
- DEBUG(0,(__location__ " Failed to alloc record\n"));
+
+ 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;
}
- 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);
+ 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;
}
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) {
talloc_free(tmp_ctx);
}
}
-
+
return 0;
failed:
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;
}
- DEBUG(5,(__location__ " Commit transaction on db 0x%08x\n", ctx->db_id));
+ if (h->nested_cancel) {
+ db->transaction_cancel(db);
+ DEBUG(5,(__location__ " Failed transaction commit after nested cancel\n"));
+ return -1;
+ }
- if (h->m_write == NULL) {
- /* no changes were made */
- talloc_free(h);
- ctx->transaction = NULL;
+ 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.
*/
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(),
- CTDB_CONTROL_TRANS2_COMMIT, h->ctx->db_id, 0,
- db_ctdb_marshall_finish(h->m_write), NULL, NULL, &status);
+ 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 == 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\n"));
- ctdbd_control_local(messaging_ctdbd_connection(), CTDB_CONTROL_TRANS2_ERROR,
+ 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;
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\n"));
- ctdbd_control_local(messaging_ctdbd_connection(), CTDB_CONTROL_TRANS2_ERROR, h->ctx->db_id,
+ 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 -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;
{
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);
+ return db_ctdb_ltdb_store(crec->ctdb_ctx, rec->key, &(crec->header), data);
}
? "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,
+ hex_encode_talloc(data, (unsigned char *)data->key.dptr,
data->key.dsize)));
if (tdb_chainunlock(crec->ctdb_ctx->wtdb->tdb, data->key) != 0) {
again:
if (DEBUGLEVEL >= 10) {
- char *keystr = hex_encode(result, key.dptr, key.dsize);
+ 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 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,
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;
git.samba.org / amitay / samba.git / blobdiff