fds garbage. Invalid offset on new page.

[Petr]

SDK 4.0.0-2.alpha

When run garbage collection, sometimes invalid offset on new page is present. Adding next string fix this. m_swap_page.write_offset = FDS_PAGE_TAG_SIZE; // [FIX]

I did correctly?

Full function text:

static ret_code_t gc_swap()

{ uint32_t ret; uint16_t const gc = m_gc.cur_page;

CRITICAL_SECTION_ENTER();
uint16_t const records_open = m_pages[gc].records_open;
CRITICAL_SECTION_EXIT();

if (records_open == 0)
{
    /** The page being GC will be the new swap, and the current swap
     *  will be used as a valid page. */
    uint32_t const * const p_addr = m_swap_page.p_addr;

    m_swap_page.p_addr = m_pages[gc].p_addr;
    m_pages[gc].p_addr = p_addr;

    m_pages[gc].write_offset = m_swap_page.write_offset;

    // Erase the new swap page.
    ret = fs_erase(&fs_config, m_swap_page.p_addr, FDS_PHY_PAGES_IN_VPAGE);

    m_swap_page.write_offset = FDS_PAGE_TAG_SIZE; // [FIX]
    
    m_gc.state = GC_TAG_VALID;
}
else
{
    /** If there are open records, we can't GC the page anymore.
     *  Discard the swap and try to GC another page. */
    ret = gc_erase_swap();
}

return ret;

}

[Petr]

Hi! I save bond data and periodic save my custom parameters. When save my custom parameters and the flash page ends, fds_write() return FDS_ERR_NO_SPACE_IN_FLASH. It runs fds_gc(). In the second iteration, result of fds_gc() is erased page and new page with data at error offset, see pics. This error offset equal length of bond data. FDS_VIRTUAL_PAGES =2 for simplify.

bool saveFile (dataFile_t &data)

{ ret_code_t retval; fds_record_key_t key; fds_record_chunk_t chunk; fds_record_desc_t descriptor;

clearFile(data);

// Fill in the record keys.
key.type     = SETUP_PARAMETERS_TYPE;
key.instance = data.fileId;

// Initialize the record chunk, pointing it to the data to be stored.
chunk.p_data       = data.pointer;
chunk.length_words = data.length;

// Write the record to flash.
retval = fds_write /*fds_update*/ (&descriptor,
                   key,
                   1,
                   &chunk);

if (retval != NRF_SUCCESS)
{
    if (retval == FDS_ERR_NO_SPACE_IN_FLASH)
    {
        //Garbage collection reclaims the flash space occupied by records which have been cleared using fds_clear
        fds_gc();
        vTaskDelay(GC_WAIT_100MLS);
        // Write the record to flash.
        retval = fds_write (&descriptor,
                            key,
                            1,
                            &chunk);
        if (retval != NRF_SUCCESS) return false;
    }
    else return false;
}
return true;

}