OVMS3-idf/components/nvs_flash/src/nvs_pagemanager.cpp
Sagar Bijwe 5a27a63541 nvs-flash: Support for blobs larger than half of SPI Flash sector size
This change removes the earlier limitation of 1984 bytes for storing data-blobs.
Blobs larger than the sector size are split and stored on multiple sectors.
For this purpose, two new datatypes (multi-page index and multi-page data) are
added for entries stored in the sectors. The underlying read, write, erase and find
operations are modified to support these large blobs. The change is transparent
to users of the library and no special APIs need to be used to store these large
blobs.
2018-07-20 00:13:15 +05:30

238 lines
6.9 KiB
C++

// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// 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.
#include "nvs_pagemanager.hpp"
namespace nvs
{
esp_err_t PageManager::load(uint32_t baseSector, uint32_t sectorCount)
{
mBaseSector = baseSector;
mPageCount = sectorCount;
mPageList.clear();
mFreePageList.clear();
mPages.reset(new Page[sectorCount]);
for (uint32_t i = 0; i < sectorCount; ++i) {
auto err = mPages[i].load(baseSector + i);
if (err != ESP_OK) {
return err;
}
uint32_t seqNumber;
if (mPages[i].getSeqNumber(seqNumber) != ESP_OK) {
mFreePageList.push_back(&mPages[i]);
} else {
auto pos = std::find_if(std::begin(mPageList), std::end(mPageList), [=](const Page& page) -> bool {
uint32_t otherSeqNumber;
return page.getSeqNumber(otherSeqNumber) == ESP_OK && otherSeqNumber > seqNumber;
});
if (pos == mPageList.end()) {
mPageList.push_back(&mPages[i]);
} else {
mPageList.insert(pos, &mPages[i]);
}
}
}
if (mPageList.empty()) {
mSeqNumber = 0;
return activatePage();
} else {
uint32_t lastSeqNo;
ESP_ERROR_CHECK( mPageList.back().getSeqNumber(lastSeqNo) );
mSeqNumber = lastSeqNo + 1;
}
// if power went out after a new item for the given key was written,
// but before the old one was erased, we end up with a duplicate item
Page& lastPage = back();
size_t lastItemIndex = SIZE_MAX;
Item item;
size_t itemIndex = 0;
while (lastPage.findItem(Page::NS_ANY, ItemType::ANY, nullptr, itemIndex, item) == ESP_OK) {
itemIndex += item.span;
lastItemIndex = itemIndex;
}
if (lastItemIndex != SIZE_MAX) {
auto last = PageManager::TPageListIterator(&lastPage);
TPageListIterator it;
for (it = begin(); it != last; ++it) {
if ((it->state() != Page::PageState::FREEING) &&
(it->eraseItem(item.nsIndex, item.datatype, item.key, item.chunkIndex) == ESP_OK)) {
break;
}
}
if ((it == last) && (item.datatype == ItemType::BLOB_IDX)) {
/* Rare case in which the blob was stored using old format, but power went just after writing
* blob index during modification. Loop again and delete the old version blob*/
for (it = begin(); it != last; ++it) {
if ((it->state() != Page::PageState::FREEING) &&
(it->eraseItem(item.nsIndex, ItemType::BLOB, item.key, item.chunkIndex) == ESP_OK)) {
break;
}
}
}
}
// check if power went out while page was being freed
for (auto it = begin(); it!= end(); ++it) {
if (it->state() == Page::PageState::FREEING) {
Page* newPage = &mPageList.back();
if (newPage->state() == Page::PageState::ACTIVE) {
auto err = newPage->erase();
if (err != ESP_OK) {
return err;
}
mPageList.erase(newPage);
mFreePageList.push_back(newPage);
}
auto err = activatePage();
if (err != ESP_OK) {
return err;
}
newPage = &mPageList.back();
err = it->copyItems(*newPage);
if (err != ESP_OK && err != ESP_ERR_NVS_NOT_FOUND) {
return err;
}
err = it->erase();
if (err != ESP_OK) {
return err;
}
Page* p = static_cast<Page*>(it);
mPageList.erase(it);
mFreePageList.push_back(p);
break;
}
}
// partition should have at least one free page
if (mFreePageList.size() == 0) {
return ESP_ERR_NVS_NO_FREE_PAGES;
}
return ESP_OK;
}
esp_err_t PageManager::requestNewPage()
{
if (mFreePageList.empty()) {
return ESP_ERR_NVS_INVALID_STATE;
}
// do we have at least two free pages? in that case no erasing is required
if (mFreePageList.size() >= 2) {
return activatePage();
}
// find the page with the higest number of erased items
TPageListIterator maxUnusedItemsPageIt;
size_t maxUnusedItems = 0;
for (auto it = begin(); it != end(); ++it) {
auto unused = Page::ENTRY_COUNT - it->getUsedEntryCount();
if (unused > maxUnusedItems) {
maxUnusedItemsPageIt = it;
maxUnusedItems = unused;
}
}
if (maxUnusedItems == 0) {
return ESP_ERR_NVS_NOT_ENOUGH_SPACE;
}
esp_err_t err = activatePage();
if (err != ESP_OK) {
return err;
}
Page* newPage = &mPageList.back();
Page* erasedPage = maxUnusedItemsPageIt;
#ifndef NDEBUG
size_t usedEntries = erasedPage->getUsedEntryCount();
#endif
err = erasedPage->markFreeing();
if (err != ESP_OK) {
return err;
}
err = erasedPage->copyItems(*newPage);
if (err != ESP_OK && err != ESP_ERR_NVS_NOT_FOUND) {
return err;
}
err = erasedPage->erase();
if (err != ESP_OK) {
return err;
}
#ifndef NDEBUG
assert(usedEntries == newPage->getUsedEntryCount());
#endif
mPageList.erase(maxUnusedItemsPageIt);
mFreePageList.push_back(erasedPage);
return ESP_OK;
}
esp_err_t PageManager::activatePage()
{
if (mFreePageList.empty()) {
return ESP_ERR_NVS_NOT_ENOUGH_SPACE;
}
Page* p = &mFreePageList.front();
if (p->state() == Page::PageState::CORRUPT) {
auto err = p->erase();
if (err != ESP_OK) {
return err;
}
}
mFreePageList.pop_front();
mPageList.push_back(p);
p->setSeqNumber(mSeqNumber);
++mSeqNumber;
return ESP_OK;
}
esp_err_t PageManager::fillStats(nvs_stats_t& nvsStats)
{
nvsStats.used_entries = 0;
nvsStats.free_entries = 0;
nvsStats.total_entries = 0;
esp_err_t err = ESP_OK;
// list of used pages
for (auto p = mPageList.begin(); p != mPageList.end(); ++p) {
err = p->calcEntries(nvsStats);
if (err != ESP_OK) {
return err;
}
}
// free pages
nvsStats.total_entries += mFreePageList.size() * Page::ENTRY_COUNT;
nvsStats.free_entries += mFreePageList.size() * Page::ENTRY_COUNT;
return err;
}
} // namespace nvs