cache.c

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/* -*- C -*- */
/*
 * Copyright (c) 2015-2020 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.
 *
 */


#define M0_TRACE_SUBSYSTEM M0_TRACE_SUBSYS_CONF
#include "lib/trace.h"

#include "conf/cache.h"
#include "conf/obj_ops.h"   /* m0_conf_obj_delete */
#include "conf/preload.h"   /* m0_confx_to_string */
#include "motr/magic.h"     /* M0_CONF_OBJ_MAGIC, M0_CONF_CACHE_MAGIC */
#include "conf/onwire.h"    /* m0_confx */
#include "lib/errno.h"      /* EEXIST */
#include "lib/memory.h"     /* M0_ALLOC_PTR, M0_ALLOC_ARR */

M0_TL_DESCR_DEFINE(m0_conf_cache, "registered m0_conf_obj-s", ,
                   struct m0_conf_obj, co_cache_link, co_gen_magic,
                   M0_CONF_OBJ_MAGIC, M0_CONF_CACHE_MAGIC);
M0_TL_DEFINE(m0_conf_cache, M0_INTERNAL, struct m0_conf_obj);

M0_INTERNAL void m0_conf_cache_lock(struct m0_conf_cache *cache)
{
        m0_mutex_lock(cache->ca_lock);
}

M0_INTERNAL void m0_conf_cache_unlock(struct m0_conf_cache *cache)
{
        m0_mutex_unlock(cache->ca_lock);
}

M0_INTERNAL bool m0_conf_cache_is_locked(const struct m0_conf_cache *cache)
{
        return m0_mutex_is_locked(cache->ca_lock);
}

M0_INTERNAL void
m0_conf_cache_init(struct m0_conf_cache *cache, struct m0_mutex *lock)
{
        M0_ENTRY();

        m0_conf_cache_tlist_init(&cache->ca_registry);
        cache->ca_lock = lock;
        cache->ca_ver  = 0;
        cache->ca_fid_counter = 0;

        M0_LEAVE();
}

M0_INTERNAL int
m0_conf_cache_add(struct m0_conf_cache *cache, struct m0_conf_obj *obj)
{
        const struct m0_conf_obj *x;

        M0_ENTRY();
        M0_PRE(m0_conf_cache_is_locked(cache));
        M0_PRE(!m0_conf_cache_tlink_is_in(obj));

        x = m0_conf_cache_lookup(cache, &obj->co_id);
        if (x != NULL)
                return M0_ERR(-EEXIST);
        m0_conf_cache_tlist_add(&cache->ca_registry, obj);
        return M0_RC(0);
}

M0_INTERNAL bool m0_conf_cache_contains(struct m0_conf_cache *cache,
                                        const struct m0_fid *fid)
{
        bool ret;

        m0_conf_cache_lock(cache);
        ret = m0_conf_cache_lookup(cache, fid) != NULL;
        m0_conf_cache_unlock(cache);
        return ret;
}

M0_INTERNAL struct m0_conf_obj *
m0_conf_cache_lookup(const struct m0_conf_cache *cache,
                     const struct m0_fid *id)
{
        return m0_tl_find(m0_conf_cache, obj, &cache->ca_registry,
                          m0_fid_eq(&obj->co_id, id));
}

static void _obj_del(struct m0_conf_obj *obj)
{
        M0_ENTRY("obj="FID_F, FID_P(&obj->co_id));

        m0_conf_cache_tlist_del(obj);
        m0_conf_obj_delete(obj);

        M0_LEAVE();
}

M0_INTERNAL void
m0_conf_cache_del(const struct m0_conf_cache *cache, struct m0_conf_obj *obj)
{
        M0_ENTRY();
        M0_PRE(m0_conf_cache_is_locked(cache));
        M0_PRE(m0_conf_cache_tlist_contains(&cache->ca_registry, obj));

        _obj_del(obj);

        M0_LEAVE();
}

static void conf_cache_clean(struct m0_conf_cache *cache,
                             const struct m0_conf_obj_type *type,
                             bool gc)
{
        struct m0_conf_obj *obj;

        M0_ENTRY();
        M0_PRE(m0_conf_cache_is_locked(cache));

        if (type == NULL)
                /*
                 * m0_conf_dirs are intermixed with other objects in
                 * cache->ca_registry.  m0_conf_obj_delete() of a non-dir
                 * object will fail if this object is still linked to some
                 * dir --- there is m0_conf_dir_tlink_fini() in
                 * m0_conf_obj_delete(), and m0_tlink_fini() asserts
                 * that the entry does not belong any list.
                 *
                 * Delete dir objects first.
                 */
                conf_cache_clean(cache, &M0_CONF_DIR_TYPE, gc);

        m0_tl_for(m0_conf_cache, &cache->ca_registry, obj) {
                M0_ASSERT(gc || !obj->co_deleted);
                if (type == NULL || m0_conf_obj_type(obj) == type) {
                        if (gc && !obj->co_deleted)
                                continue;
                        _obj_del(obj);
                }
        } m0_tl_endfor;
        M0_LEAVE();
}

M0_INTERNAL void m0_conf_cache_clean(struct m0_conf_cache *cache,
                                     const struct m0_conf_obj_type *type)
{
        M0_ENTRY();
        conf_cache_clean(cache, type, false);
        M0_LEAVE();
}

M0_INTERNAL void m0_conf_cache_gc(struct m0_conf_cache *cache)
{
        M0_ENTRY();
        conf_cache_clean(cache, NULL, true);
        M0_LEAVE();
}

M0_INTERNAL void m0_conf_cache_fini(struct m0_conf_cache *cache)
{
        M0_ENTRY();

        m0_conf_cache_lock(cache);
        m0_conf_cache_clean(cache, NULL);
        m0_conf_cache_tlist_fini(&cache->ca_registry);
        m0_conf_cache_unlock(cache);

        M0_LEAVE();
}

static int
conf_encode(struct m0_confx *enc, const struct m0_conf_obj *obj, bool debug)
{
        int rc;

        M0_PRE(debug ||
               (m0_conf_obj_invariant(obj) && obj->co_status == M0_CS_READY));

        rc = obj->co_ops->coo_encode(M0_CONFX_AT(enc, enc->cx_nr), obj);
        if (rc == 0)
                ++enc->cx_nr;
        return M0_RC(rc);
}

static int conf_cache_encode(const struct m0_conf_cache *cache,
                             struct m0_confx *dest, bool debug)
{
        struct m0_conf_obj *obj = NULL;
        int                 rc = 0;
        size_t              nr;
        char               *data;

        M0_ENTRY();
        M0_PRE(m0_conf_cache_is_locked(cache));

        M0_SET0(dest);

        if (!debug && !m0_tl_forall(m0_conf_cache, scan, &cache->ca_registry,
                                    m0_conf_obj_invariant((obj = scan)) &&
                                    scan->co_status == M0_CS_READY))
                return M0_ERR_INFO(-EINVAL, FID_F" status=%u",
                                   FID_P(&obj->co_id), obj->co_status);

        nr = m0_tl_reduce(m0_conf_cache, scan, &cache->ca_registry, 0,
                          + (m0_conf_obj_type(scan) != &M0_CONF_DIR_TYPE));

        M0_ALLOC_ARR(data, nr * m0_confx_sizeof());
        if (data == NULL)
                return M0_ERR(-ENOMEM);
        /* "data" is freed by m0_confx_free(dest). */
        dest->cx__objs = (void *)data;

        M0_LOG(M0_DEBUG, "Will encode %zu configuration objects", nr);
        m0_tl_for(m0_conf_cache, &cache->ca_registry, obj) {
                if (m0_conf_obj_type(obj) != &M0_CONF_DIR_TYPE) {
                        rc = conf_encode(dest, obj, debug);
                        if (rc != 0)
                                break;
                }
        } m0_tl_endfor;

        if (rc == 0) {
                M0_ASSERT(nr == dest->cx_nr);
        } else {
                m0_free(data);
                dest->cx__objs = NULL;
        }

        return M0_RC(rc);
}

M0_INTERNAL int
m0_conf_cache_to_string(struct m0_conf_cache *cache, char **str, bool debug)
{
        struct m0_confx *confx;
        int              rc;

        M0_ENTRY();

        M0_ALLOC_PTR(confx);
        if (confx == NULL)
                return M0_ERR(-ENOMEM);

        m0_conf_cache_lock(cache);
        rc = conf_cache_encode(cache, confx, debug);
        m0_conf_cache_unlock(cache);
        if (rc == 0)
                rc = m0_confx_to_string(confx, str);
        m0_confx_free(confx);
        return M0_RC(rc);
}

M0_INTERNAL int
m0_conf_cache_from_string(struct m0_conf_cache *cache, const char *str)
{
        struct m0_confx *enc;
        uint32_t         i;
        int              rc;

        M0_ENTRY();

        M0_PRE(str != NULL);
        M0_PRE(m0_conf_cache_is_locked(cache));

        rc = m0_confstr_parse(str, &enc);
        if (rc != 0)
                return M0_ERR(rc);

        for (i = 0; i < enc->cx_nr && rc == 0; ++i) {
                struct m0_conf_obj        *obj;
                const struct m0_confx_obj *xobj = M0_CONFX_AT(enc, i);

                rc = m0_conf_obj_find(cache, m0_conf_objx_fid(xobj), &obj) ?:
                        m0_conf_obj_fill(obj, xobj);
        }
        m0_confx_free(enc);
        return M0_RC(rc);
}

M0_INTERNAL int m0_conf_version(struct m0_conf_cache *cache)
{
        struct m0_conf_obj *obj;
        int                 ver = 0;

        M0_ENTRY();

        m0_conf_cache_lock(cache);
        obj = m0_conf_cache_lookup(cache, &M0_CONF_ROOT_FID);
        if (obj != NULL)
                ver = M0_CONF_CAST(obj, m0_conf_root)->rt_verno;
        m0_conf_cache_unlock(cache);
        return M0_RC(ver);
}

M0_INTERNAL struct m0_conf_obj *
m0_conf_cache_pinned(const struct m0_conf_cache *cache)
{
        M0_PRE(m0_conf_cache_is_locked(cache));
        return m0_tl_find(m0_conf_cache, obj, &cache->ca_registry,
                          obj->co_nrefs != 0);
}

#undef M0_TRACE_SUBSYSTEM