Reboot before formatting LittleFS (#5900)

Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/FSCommon.cpp

@@ -49,24 +49,6 @@ void OSFS::writeNBytes(uint16_t address, unsigned int num, const byte *input)
 }
 #endif
 
-bool lfs_assert_failed =
-    false; // Note: we use this global on all platforms, though it can only be set true on nrf52 (in our modified lfs_util.h)
-
-extern "C" void lfs_assert(const char *reason)
-{
-    LOG_ERROR("LFS assert: %s", reason);
-    lfs_assert_failed = true;
-
-#ifndef ARCH_PORTDUINO
-#ifdef FSCom
-    // CORRUPTED FILESYSTEM. This causes bootloop so
-    // might as well try formatting now.
-    LOG_ERROR("Trying FSCom.format()");
-    FSCom.format();
-#endif
-#endif
-}
-
 /**
  * @brief Copies a file from one location to another.
  *
@@ -348,10 +330,16 @@ void rmDir(const char *dirname)
 #endif
 }
 
+/**
+ * Some platforms (nrf52) might need to do an extra step before FSBegin().
+ */
+__attribute__((weak, noinline)) void preFSBegin() {}
+
 void fsInit()
 {
 #ifdef FSCom
-    spiLock->lock();
+    concurrency::LockGuard g(spiLock);
+    preFSBegin();
     if (!FSBegin()) {
         LOG_ERROR("Filesystem mount failed");
         // assert(0); This auto-formats the partition, so no need to fail here.
@@ -362,7 +350,6 @@ void fsInit()
     LOG_DEBUG("Filesystem files:");
 #endif
     listDir("/", 10);
-    spiLock->unlock();
 #endif
 }
 
@@ -400,4 +387,4 @@ void setupSDCard()
     LOG_DEBUG("Total space: %lu MB", (uint32_t)(SD.totalBytes() / (1024 * 1024)));
     LOG_DEBUG("Used space: %lu MB", (uint32_t)(SD.usedBytes() / (1024 * 1024)));
 #endif
-}
+}

src/FSCommon.h

@@ -57,7 +57,4 @@ bool renameFile(const char *pathFrom, const char *pathTo);
 std::vector<meshtastic_FileInfo> getFiles(const char *dirname, uint8_t levels);
 void listDir(const char *dirname, uint8_t levels, bool del = false);
 void rmDir(const char *dirname);
-void setupSDCard();
+void setupSDCard();
-
-extern bool lfs_assert_failed; // Note: we use this global on all platforms, though it can only be set true on nrf52 (in our
-                               // modified lfs_util.h)

src/SafeFile.cpp

@@ -8,7 +8,6 @@ static File openFile(const char *filename, bool fullAtomic)
     concurrency::LockGuard g(spiLock);
     LOG_DEBUG("Opening %s, fullAtomic=%d", filename, fullAtomic);
 #ifdef ARCH_NRF52
-    lfs_assert_failed = false;
     File file = FSCom.open(filename, FILE_O_WRITE);
     file.seek(0);
     return file;
@@ -20,7 +19,6 @@ static File openFile(const char *filename, bool fullAtomic)
     filenameTmp += ".tmp";
 
     // clear any previous LFS errors
-    lfs_assert_failed = false;
     return FSCom.open(filenameTmp.c_str(), FILE_O_WRITE);
 }
 
@@ -96,8 +94,6 @@ bool SafeFile::close()
 bool SafeFile::testReadback()
 {
     concurrency::LockGuard g(spiLock);
-    bool lfs_failed = lfs_assert_failed;
-    lfs_assert_failed = false;
 
     String filenameTmp = filename;
     filenameTmp += ".tmp";
@@ -119,7 +115,7 @@ bool SafeFile::testReadback()
         return false;
     }
 
-    return !lfs_failed;
+    return true;
 }
 
 #endif

src/platform/nrf52/main-nrf52.cpp

@@ -1,6 +1,7 @@
 #include "configuration.h"
 #include <Adafruit_TinyUSB.h>
 #include <Adafruit_nRFCrypto.h>
+#include <InternalFileSystem.h>
 #include <SPI.h>
 #include <Wire.h>
 #include <assert.h>
@@ -130,6 +131,54 @@ int printf(const char *fmt, ...)
     return res;
 }
 
+namespace
+{
+constexpr uint8_t NRF52_MAGIC_LFS_IS_CORRUPT = 0xF5;
+constexpr uint32_t MULTIPLE_CORRUPTION_DELAY_MILLIS = 20 * 60 * 1000;
+static unsigned long millis_until_formatting_again = 0;
+
+// Report the critical error from loop(), giving a chance for the screen to be initialized first.
+inline void reportLittleFSCorruptionOnce()
+{
+    static bool report_corruption = !!millis_until_formatting_again;
+    if (report_corruption) {
+        report_corruption = false;
+        RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_FLASH_CORRUPTION_UNRECOVERABLE);
+    }
+}
+} // namespace
+
+void preFSBegin()
+{
+    // The GPREGRET register keeps its value across warm boots. Check that this is a warm boot and, if GPREGRET
+    // is set to NRF52_MAGIC_LFS_IS_CORRUPT, format LittleFS.
+    if (!(NRF_POWER->RESETREAS == 0 && NRF_POWER->GPREGRET == NRF52_MAGIC_LFS_IS_CORRUPT))
+        return;
+    NRF_POWER->GPREGRET = 0;
+    millis_until_formatting_again = millis() + MULTIPLE_CORRUPTION_DELAY_MILLIS;
+    InternalFS.format();
+    LOG_INFO("LittleFS format complete; restoring default settings");
+}
+
+extern "C" void lfs_assert(const char *reason)
+{
+    LOG_ERROR("LittleFS corruption detected: %s", reason);
+    if (millis_until_formatting_again > millis()) {
+        RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_FLASH_CORRUPTION_UNRECOVERABLE);
+        const long millis_remain = millis_until_formatting_again - millis();
+        LOG_WARN("Pausing %d seconds to avoid wear on flash storage", millis_remain / 1000);
+        delay(millis_remain);
+    }
+    LOG_INFO("Rebooting to format LittleFS");
+    delay(500); // Give the serial port a bit of time to output that last message.
+    // Try setting GPREGRET with the SoftDevice first. If that fails (perhaps because the SD hasn't been initialize yet) then set
+    // NRF_POWER->GPREGRET directly.
+    if (!(sd_power_gpregret_clr(0, 0xFF) == NRF_SUCCESS && sd_power_gpregret_set(0, NRF52_MAGIC_LFS_IS_CORRUPT) == NRF_SUCCESS)) {
+        NRF_POWER->GPREGRET = NRF52_MAGIC_LFS_IS_CORRUPT;
+    }
+    NVIC_SystemReset();
+}
+
 void checkSDEvents()
 {
     if (useSoftDevice) {
@@ -154,6 +203,7 @@ void checkSDEvents()
 void nrf52Loop()
 {
     checkSDEvents();
+    reportLittleFSCorruptionOnce();
 }
 
 #ifdef USE_SEMIHOSTING
@@ -309,4 +359,4 @@ void enterDfuMode()
 #else
     enterUf2Dfu();
 #endif
-}
+}