fil_space_create

/*******************************************************************//**
Creates a space memory object and puts it to the tablespace memory cache. If
there is an error, prints an error message to the .err log.
@return    TRUE if success */
UNIV_INTERN
ibool
fil_space_create(
/*=============*/
    const char*    name,    /*!< in: space name */
    ulint        id,    /*!< in: space id */
    ulint        flags,    /*!< in: compressed page size
                and file format, or 0 */
    ulint        purpose)/*!< in: FIL_TABLESPACE, or FIL_LOG if log */
{
    fil_space_t*    space;

    /* The tablespace flags (FSP_SPACE_FLAGS) should be 0 for
    ROW_FORMAT=COMPACT
    ((table->flags & ~(~0 << DICT_TF_BITS)) == DICT_TF_COMPACT) and
    ROW_FORMAT=REDUNDANT (table->flags == 0).  For any other
    format, the tablespace flags should equal
    (table->flags & ~(~0 << DICT_TF_BITS)). */
    ut_a(flags != DICT_TF_COMPACT);
    ut_a(!(flags & (~0UL << DICT_TF_BITS)));

try_again:
    /*printf(
    "InnoDB: Adding tablespace %lu of name %s, purpose %lu\n", id, name,
    purpose);*/

    ut_a(fil_system);
    ut_a(name);

    mutex_enter(&fil_system->mutex);

    space = fil_space_get_by_name(name);

    if (UNIV_LIKELY_NULL(space)) {
      goto try_again;
    }

    space = fil_space_get_by_id(id);

    if (UNIV_LIKELY_NULL(space)) {     return(FALSE);
    }
    
    /**
     *结构体详见
     */
    space = mem_alloc(sizeof(fil_space_t));

    space->name = mem_strdup(name);
    space->id = id;

    fil_system->tablespace_version++;
    space->tablespace_version = fil_system->tablespace_version;
    space->mark = FALSE;

    if (UNIV_LIKELY(purpose == FIL_TABLESPACE && !recv_recovery_on)
        && UNIV_UNLIKELY(id > fil_system->max_assigned_id)) {
        if (!fil_system->space_id_reuse_warned) {
           
        }

        fil_system->max_assigned_id = id;
    }

    space->stop_ios = FALSE;
    space->stop_new_ops = FALSE;
    space->purpose = purpose;
    space->size = 0;
    space->flags = flags;

    space->n_reserved_extents = 0;

    space->n_pending_flushes = 0;
    space->n_pending_ops = 0;

    //初始化chain链表
    UT_LIST_INIT(space->chain);
    space->magic_n = FIL_SPACE_MAGIC_N;

    rw_lock_create(fil_space_latch_key, &space->latch, SYNC_FSP);
    
    //分别以id和name作为哈希值,放入fil_system相应哈希表中
    HASH_INSERT(fil_space_t, hash, fil_system->spaces, id, space);

    HASH_INSERT(fil_space_t, name_hash, fil_system->name_hash,ut_fold_string(name), space);

    space->is_in_unflushed_spaces = FALSE;
    
    //放入lru中
    UT_LIST_ADD_LAST(space_list, fil_system->space_list, space);

    mutex_exit(&fil_system->mutex);

    return(TRUE);
}

/*******************************************************************//**
Returns the table space by a given name, NULL if not found. */
UNIV_INLINE
fil_space_t*
fil_space_get_by_name(
/*==================*/
    const char*    name)    /*!< in: space name */
{
    fil_space_t*    space;
    ulint        fold;

    ut_ad(mutex_own(&fil_system->mutex));

    fold = ut_fold_string(name);

    HASH_SEARCH(name_hash, fil_system->name_hash, fold,
            fil_space_t*, space,
            ut_ad(space->magic_n == FIL_SPACE_MAGIC_N),
            !strcmp(name, space->name));

    return(space);
}