7d2e59813f
On flash NVS was stored one entry after another including the metadata of each entry. This has the disadvantage that when an incomplete write is performed (e.g. due to power failure) the complete sector had to be rewritten to get a completely functional system. The present rewrite changed the storage in flash of the data. For each sector the data is now written as follows: the data itself at the beginning of the sector (one after the other), the metadata (id, length, data offset in the sector, and a crc of the metadata) is written from the end of the sector. The metadata is of fixed size (8 byte) and for a sector that is completely occupied a metadata entry of all zeros is used. Writing data to flash always is done by: 1. Writing the data, 2. Writing the metadata. If an incomplete write is done NVS will ignore this incomplete write. At the same time the following improvements were done: 1. NVS now support 65536 sectors of each 65536 byte. 2. The sector size no longer requires to be a power of 2 (but it still needs to be a multiple of the flash erase page size). 3. NVS now also keeps track of the free space available. Signed-off-by: Laczen JMS <laczenjms@gmail.com> |
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