seg_dict.h

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/* -*- C -*- */
/*
 * Copyright (c) 2013-2020 Seagate Technology LLC and/or its Affiliates
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For any questions about this software or licensing,
 * please email opensource@seagate.com or cortx-questions@seagate.com.
 *
 */


#pragma once

#ifndef __MOTR_BE_SEG_DICT_H__
#define __MOTR_BE_SEG_DICT_H__

/*
 * Design highlights:
 * - bh_dict (BE list) contains entries sorted by keys. This fact is used in
 *   the iterator.
 * - XXX Seg_dict is not thread-safe. For users that access seg_dict during
 *   mkfs/init process, it is not a problem, because they're serialised by
 *   serial motr/setup. But we should be aware of the next use-cases:
 *     1. Multiple instances of cm/ag_store may modify/lookup seg_dict
 *        concurrently.
 *     2. Ad stob domains may be created/destroyed concurrently with
 *        cm/ag_store. See m0_storage_dev.
 * - XXX Seg dict iterator returns pointers to potentially unpinned memory. It
 *   may cause problems with `this_key` strings.
 */

struct m0_be_tx;
struct m0_be_seg;
struct m0_be_tx_credit;

M0_INTERNAL void m0_be_seg_dict_init(struct m0_be_seg *seg);
M0_INTERNAL void m0_be_seg_dict_fini(struct m0_be_seg *seg);
M0_INTERNAL int m0_be_seg_dict_lookup(struct m0_be_seg  *seg,
                                      const char        *name,
                                      void             **out);
M0_INTERNAL int m0_be_seg_dict_begin(struct m0_be_seg  *seg,
                                     const char        *start_key,
                                     const char       **this_key,
                                     void             **this_rec);
M0_INTERNAL int m0_be_seg_dict_next(struct m0_be_seg  *seg,
                                    const char        *prefix,
                                    const char        *start_key,
                                    const char       **this_key,
                                    void             **this_rec);

/* tx based dictionary interface */
M0_INTERNAL int m0_be_seg_dict_insert(struct m0_be_seg *seg,
                                      struct m0_be_tx  *tx,
                                      const char       *name,
                                      void             *value);
M0_INTERNAL int m0_be_seg_dict_delete(struct m0_be_seg *seg,
                                      struct m0_be_tx  *tx,
                                      const char       *name);
M0_INTERNAL void m0_be_seg_dict_create(struct m0_be_seg *seg,
                                       struct m0_be_tx  *tx);
M0_INTERNAL void m0_be_seg_dict_destroy(struct m0_be_seg *seg,
                                        struct m0_be_tx  *tx);

M0_INTERNAL void m0_be_seg_dict_create_credit(struct m0_be_seg       *seg,
                                              struct m0_be_tx_credit *accum);
M0_INTERNAL void m0_be_seg_dict_destroy_credit(struct m0_be_seg       *seg,
                                               struct m0_be_tx_credit *accum);
M0_INTERNAL void m0_be_seg_dict_insert_credit(struct m0_be_seg       *seg,
                                              const char             *name,
                                              struct m0_be_tx_credit *accum);
M0_INTERNAL void m0_be_seg_dict_delete_credit(struct m0_be_seg       *seg,
                                              const char             *name,
                                              struct m0_be_tx_credit *accum);

#endif /* __MOTR_BE_SEG_DICT_H__ */

/*
 *  Local variables:
 *  c-indentation-style: "K&R"
 *  c-basic-offset: 8
 *  tab-width: 8
 *  fill-column: 80
 *  scroll-step: 1
 *  End:
 */
/*
 * vim: tabstop=8 shiftwidth=8 noexpandtab textwidth=80 nowrap
 */