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authorVolker Lendecke <vl@samba.org>2012-03-24 13:49:40 +0100
committerVolker Lendecke <vl@samba.org>2012-04-17 10:21:00 +0200
commitbd9178506ed8796a0aa7e4e757f2adc20dcae4f8 (patch)
treecdc1b73e0118c40a62da321b8642d68577f65812 /source3/lib/dbwrap
parentba8f19c556724aaa2de71473234f8bab1f301a7f (diff)
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s3: Add dbwrap_cache
This is a caching layer for the notify database and potentially for the brlock database. It caches the parse_record operation as long as the underlying seqnum does not change.
Diffstat (limited to 'source3/lib/dbwrap')
-rw-r--r--source3/lib/dbwrap/dbwrap_cache.c210
-rw-r--r--source3/lib/dbwrap/dbwrap_cache.h32
2 files changed, 242 insertions, 0 deletions
diff --git a/source3/lib/dbwrap/dbwrap_cache.c b/source3/lib/dbwrap/dbwrap_cache.c
new file mode 100644
index 0000000000..43c85f7b09
--- /dev/null
+++ b/source3/lib/dbwrap/dbwrap_cache.c
@@ -0,0 +1,210 @@
+/*
+ Unix SMB/CIFS implementation.
+ Cache db contents for parse_record based on seqnum
+ Copyright (C) Volker Lendecke 2012
+
+ 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"
+#include "lib/dbwrap/dbwrap.h"
+#include "lib/dbwrap/dbwrap_private.h"
+#include "lib/dbwrap/dbwrap_rbt.h"
+#include "lib/dbwrap/dbwrap_cache.h"
+
+struct db_cache_ctx {
+ int seqnum;
+ struct db_context *backing;
+ struct db_context *positive;
+ struct db_context *negative;
+};
+
+static void dbwrap_cache_validate(struct db_cache_ctx *ctx)
+{
+ if (ctx->seqnum == dbwrap_get_seqnum(ctx->backing)) {
+ return;
+ }
+ TALLOC_FREE(ctx->positive);
+ ctx->positive = db_open_rbt(ctx);
+ TALLOC_FREE(ctx->negative);
+ ctx->negative = db_open_rbt(ctx);
+}
+
+static NTSTATUS dbwrap_cache_parse_record(
+ struct db_context *db, TDB_DATA key,
+ void (*parser)(TDB_DATA key, TDB_DATA data, void *private_data),
+ void *private_data)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ TDB_DATA value;
+ NTSTATUS status;
+
+ dbwrap_cache_validate(ctx);
+
+ if (ctx->positive != NULL) {
+ status = dbwrap_parse_record(
+ ctx->positive, key, parser, private_data);
+ if (NT_STATUS_IS_OK(status)) {
+ return status;
+ }
+ }
+ if ((ctx->negative != NULL) && dbwrap_exists(ctx->negative, key)) {
+ return NT_STATUS_NOT_FOUND;
+ }
+
+ status = dbwrap_fetch(ctx->backing, talloc_tos(), key, &value);
+
+ if (NT_STATUS_IS_OK(status)) {
+ dbwrap_store(ctx->positive, key, value, 0);
+ parser(key, value, private_data);
+ TALLOC_FREE(value.dptr);
+ return NT_STATUS_OK;
+ }
+
+ if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
+ char c = '\0';
+ value.dptr = (uint8_t *)&c;
+ value.dsize = sizeof(c);
+ dbwrap_store(ctx->negative, key, value, 0);
+ return NT_STATUS_NOT_FOUND;
+ }
+ return status;
+}
+
+static struct db_record *dbwrap_cache_fetch_locked(
+ struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ return dbwrap_fetch_locked(ctx->backing, mem_ctx, key);
+}
+
+static int dbwrap_cache_traverse(struct db_context *db,
+ int (*f)(struct db_record *rec,
+ void *private_data),
+ void *private_data)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ NTSTATUS status;
+ int ret;
+ status = dbwrap_traverse(ctx->backing, f, private_data, &ret);
+ if (!NT_STATUS_IS_OK(status)) {
+ return -1;
+ }
+ return ret;
+}
+
+static int dbwrap_cache_traverse_read(struct db_context *db,
+ int (*f)(struct db_record *rec,
+ void *private_data),
+ void *private_data)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ NTSTATUS status;
+ int ret;
+ status = dbwrap_traverse_read(ctx->backing, f, private_data, &ret);
+ if (!NT_STATUS_IS_OK(status)) {
+ return -1;
+ }
+ return ret;
+}
+
+static int dbwrap_cache_get_seqnum(struct db_context *db)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ return dbwrap_get_seqnum(ctx->backing);
+}
+
+static int dbwrap_cache_get_flags(struct db_context *db)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ return dbwrap_get_flags(ctx->backing);
+}
+
+static int dbwrap_cache_transaction_start(struct db_context *db)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ return dbwrap_transaction_start(ctx->backing);
+}
+
+static int dbwrap_cache_transaction_commit(struct db_context *db)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ return dbwrap_transaction_commit(ctx->backing);
+}
+
+static int dbwrap_cache_transaction_cancel(struct db_context *db)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+ return dbwrap_transaction_cancel(ctx->backing);
+}
+
+static int dbwrap_cache_exists(struct db_context *db, TDB_DATA key)
+{
+ struct db_cache_ctx *ctx = talloc_get_type_abort(
+ db->private_data, struct db_cache_ctx);
+
+ if (ctx->positive && dbwrap_exists(ctx->positive, key)) {
+ return true;
+ }
+ if (ctx->negative && dbwrap_exists(ctx->negative, key)) {
+ return false;
+ }
+ return dbwrap_exists(ctx->backing, key);
+}
+
+struct db_context *db_open_cache(TALLOC_CTX *mem_ctx,
+ struct db_context *backing)
+{
+ struct db_context *db;
+ struct db_cache_ctx *ctx;
+
+ db = talloc(mem_ctx, struct db_context);
+ if (db == NULL) {
+ return NULL;
+ }
+ ctx = talloc_zero(db, struct db_cache_ctx);
+ if (ctx == NULL) {
+ TALLOC_FREE(db);
+ return NULL;
+ }
+
+ ctx->seqnum = -1;
+ ctx->backing = talloc_move(ctx, &backing);
+ db->private_data = ctx;
+ dbwrap_cache_validate(ctx);
+
+ db->fetch_locked = dbwrap_cache_fetch_locked;
+ db->traverse = dbwrap_cache_traverse;
+ db->traverse_read = dbwrap_cache_traverse_read;
+ db->get_seqnum = dbwrap_cache_get_seqnum;
+ db->get_flags = dbwrap_cache_get_flags;
+ db->transaction_start = dbwrap_cache_transaction_start;
+ db->transaction_commit = dbwrap_cache_transaction_commit;
+ db->transaction_cancel = dbwrap_cache_transaction_cancel;
+ db->parse_record = dbwrap_cache_parse_record;
+ db->exists = dbwrap_cache_exists;
+ db->wipe = NULL;
+ db->lock_order = 0;
+ db->persistent = false;
+ return db;
+}
diff --git a/source3/lib/dbwrap/dbwrap_cache.h b/source3/lib/dbwrap/dbwrap_cache.h
new file mode 100644
index 0000000000..cd290e15f8
--- /dev/null
+++ b/source3/lib/dbwrap/dbwrap_cache.h
@@ -0,0 +1,32 @@
+/*
+ Unix SMB/CIFS implementation.
+ Database interface wrapper around ctdbd
+ Copyright (C) Volker Lendecke 2012
+
+ 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/>.
+*/
+
+#ifndef __DBWRAP_CACHE_H__
+#define __DBWRAP_CACHE_H__
+
+#include <talloc.h>
+
+#include "dbwrap/dbwrap_private.h"
+
+struct db_context;
+
+struct db_context *db_open_cache(TALLOC_CTX *mem_ctx,
+ struct db_context *backing);
+
+#endif /* __DBWRAP_CACHE_H__ */