SPIFFS opens file but reads no data

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1

I am trying to use spiffs to store an html file but I can’t seem to fread from it. The set up as well as fopen works, but fread returns 0.

My Partition Table

# Note: if you change the phy_init or app partition offset, make sure to change the offset in Kconfig.projbuild
# Name,   Type, SubType, Offset,  Size, Flags
nvs,      data, nvs,     0x10000,  0x6000
otadata,  data, ota,     0x16000,  0x2000
phy_init, data, phy,     0x18000,  0x1000
ota_0,    0,    ota_0,   0x20000,  1500K
ota_1,    0,    ota_1,   ,         1500K
storage,  data, nvs,     ,         0x10000
spiffs,  data, spiffs,   0x327000, 0x30000

sdkconfig

#
# SPIFFS Configuration
#
CONFIG_SPIFFS_MAX_PARTITIONS=3

#
# SPIFFS Cache Configuration
#
CONFIG_SPIFFS_CACHE=y
CONFIG_SPIFFS_CACHE_WR=y
CONFIG_SPIFFS_CACHE_STATS=
CONFIG_SPIFFS_PAGE_CHECK=y
CONFIG_SPIFFS_GC_MAX_RUNS=10
CONFIG_SPIFFS_GC_STATS=
CONFIG_SPIFFS_PAGE_SIZE=256
CONFIG_SPIFFS_OBJ_NAME_LEN=32
CONFIG_SPIFFS_USE_MAGIC=y
CONFIG_SPIFFS_USE_MAGIC_LENGTH=y
CONFIG_SPIFFS_META_LENGTH=4
CONFIG_SPIFFS_USE_MTIME=y

#
# Debug Configuration
#
CONFIG_SPIFFS_DBG=
CONFIG_SPIFFS_API_DBG=
CONFIG_SPIFFS_GC_DBG=
CONFIG_SPIFFS_CACHE_DBG=
CONFIG_SPIFFS_CHECK_DBG=
CONFIG_SPIFFS_TEST_VISUALISATION=

Steps I took

./mkspiffs -c ./components/wifi/resources -b 4096 -p 256 -s 0x30000 spiffs.bin

./components/wifi/resources has two files in it, a .txt and a .html

python ./amazon-freertos/vendors/espressif/esp-idf/components/esptool_py/esptool/esptool.py --chip esp32 --port /dev/cu.SLAB_USBtoUART --baud 115200 write_flash -z 0x327000 spiffs.bin

The code:

esp_err_t init_spiffs(){
    esp_vfs_spiffs_conf_t conf = {
            .base_path = "/spiffs",
            .partition_label = NULL,
            .max_files = 5,
            .format_if_mount_failed = true
    };

    // Use settings defined above to initialize and mount SPIFFS filesystem.
    // Note: esp_vfs_spiffs_register is an all-in-one convenience function.
    esp_err_t ret = esp_vfs_spiffs_register(&conf);

    if (ret != ESP_OK) {
        if (ret == ESP_FAIL) {
            ESP_LOGE(MAIN, "Failed to mount or format filesystem");
        } else if (ret == ESP_ERR_NOT_FOUND) {
            ESP_LOGE(MAIN, "Failed to find SPIFFS partition");
        } else {
            ESP_LOGE(MAIN, "Failed to initialize SPIFFS (%s)", esp_err_to_name(ret));
        }
        return ret;
    }

    size_t total = 0, used = 0;
    ret = esp_spiffs_info(NULL, &total, &used);
    if (ret != ESP_OK) {
        ESP_LOGE(MAIN, "Failed to get SPIFFS partition information (%s)", esp_err_to_name(ret));
    } else {
        ESP_LOGI(MAIN, "Partition size: total: %d, used: %d", total, used);
    }
    return ESP_OK;
}
...
int app_main( void ){
    // Initialize SPIFFS
    ret = init_spiffs();
    if(ret != ESP_OK){
        ESP_LOGI(MAIN, "init_spiffs(): %s", esp_err_to_name(ret));
        return 0;
    }

    ESP_LOGI(MAIN, "Opening file");
    FILE* f = fopen("/spiffs/foo.txt", "r");
    if (f == NULL) {
        ESP_LOGI(MAIN, "Failed to open file for writing");
    }

    char buf[100] = {0};
    int bytes_read = fread(buf, 1, 100, f);
    ESP_LOGI(MAIN, "bytes read: %i", bytes_read);
    for(int i = 0; i < 100; i++){
        printf("%c\n", buf[i]);
    }

Console output:

I (340) MAIN: Partition size: total: 173441, used: 28614
I (340) MAIN: Opening file
I (340) MAIN: bytes read: 0

Any help would be appreciated. Thanks!

2

SPIFFS is not a library we use in any of our examples that I know of. Did you do the integration yourself or are using using integrations provided elsewhere? If the latter I would suggest asking the question wherever you obtained the code from originally.

1 Like
3

Oh ya I mistakenly thought it was from FreeRTOS but its from Espressif. Thanks!

4

@isnore, I’ve moved this thread to the Espressif category so that members of the @Espressif team can answer this question for you.

1 Like
5

@isnore Can you please check ./mkspiffs --version output against the config options (from sdkconfig) you provided above? Thread at https://github.com/espressif/esp-idf/issues/1732 can help you further.

1 Like
6

Here is the output from:

./mkspiffs --version

mkspiffs ver. 0.2.3
Build configuration name: esp-idf
SPIFFS ver. 0.3.7-5-gf5e26c4
Extra build flags: -DSPIFFS_OBJ_META_LEN=4
SPIFFS configuration:
  SPIFFS_OBJ_NAME_LEN: 32
  SPIFFS_OBJ_META_LEN: 4
  SPIFFS_USE_MAGIC: 1
  SPIFFS_USE_MAGIC_LENGTH: 1
  SPIFFS_ALIGNED_OBJECT_INDEX_TABLES: 0

sdkconfig

#
# SPIFFS Configuration
#
CONFIG_SPIFFS_MAX_PARTITIONS=3

#
# SPIFFS Cache Configuration
#
CONFIG_SPIFFS_CACHE=y
CONFIG_SPIFFS_CACHE_WR=y
CONFIG_SPIFFS_CACHE_STATS=
CONFIG_SPIFFS_PAGE_CHECK=y
CONFIG_SPIFFS_GC_MAX_RUNS=10
CONFIG_SPIFFS_GC_STATS=
CONFIG_SPIFFS_PAGE_SIZE=256
CONFIG_SPIFFS_OBJ_NAME_LEN=32
CONFIG_SPIFFS_USE_MAGIC=y
CONFIG_SPIFFS_USE_MAGIC_LENGTH=y
CONFIG_SPIFFS_META_LENGTH=4
CONFIG_SPIFFS_USE_MTIME=y

#
# Debug Configuration
#
CONFIG_SPIFFS_DBG=
CONFIG_SPIFFS_API_DBG=
CONFIG_SPIFFS_GC_DBG=
CONFIG_SPIFFS_CACHE_DBG=
CONFIG_SPIFFS_CHECK_DBG=
CONFIG_SPIFFS_TEST_VISUALISATION=
7

@isnore I created two files a.html and a.txt with the same folder structure. fread() worked for me. Here is the code I used:

ESP_LOGI(TAG, "Reading file");
FILE* f = fopen("/spiffs/a.html", "r");
if (f == NULL) {
    ESP_LOGE(TAG, "Failed to open file for reading");
    return;
}
char line[300] = {0};
int bytes_read = fread(line, 1, 300, f);
ESP_LOGI(TAG, "bytes read: %i", bytes_read);
printf("\n\n%s\n", line);
fclose(f);

Can you run the command ./mkspiffs -l spiffs.bin and share the output.

You can also unpack the generated image using ./mkspiffs -u <dest_dir> spiffs.bin and verify contents of the files.

8

./mkspiffs -l spiffs.bin output

27797   /capture_portal.html
30      /foo.txt

When I unpack the spiffs.bin I do see the two files with the correct content.

I ran the following code:

    // Initialize NVS
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        nvs_flash_init();
    }

    // Initialize SPIFFS
    ret = init_spiffs();
    if(ret != ESP_OK){
        ESP_LOGI(MAIN, "init_spiffs(): %s", esp_err_to_name(ret));
        return 0;
    }

    ESP_LOGI(MAIN, "Opening file");
    char line[300] = {0};

    FILE* f = fopen("/spiffs/foo.txt", "r");

    if (f == NULL) {
        ESP_LOGE(MAIN, "Failed to open file for reading");
        return -1;
    }

    int bytes_read = fread(line, 1, 300, f);
    ESP_LOGI(MAIN, "bytes read: %i", bytes_read);

    printf("\n\n%s\n", line);
    fclose(f);

resulting in the following output:

I (887) MAIN: Partition size: total: 173441, used: 28865
I (887) MAIN: Opening file
I (897) MAIN: bytes read: 0

Is there some sort of configuration option I need to change? Please have a look at the sdkconfig I provided above? I read something about changing the meta data length field.

Update

I am able to create a file, write to it, and read back from it. But still can’t access files I flashed to the board. See code and output below:

// Initialize SPIFFS
    ret = init_spiffs();
    if(ret != ESP_OK){
        ESP_LOGI(MAIN, "init_spiffs(): %s", esp_err_to_name(ret));
        return 0;
    }

    ESP_LOGI(MAIN, "Opening file");
    char line[300] = {0};

    FILE* f = fopen("/spiffs/hello.txt", "w");

    if (f == NULL) {
        ESP_LOGE(MAIN, "Failed to open file for reading");
        return -1;
    }
    fprintf(f, "Hello World!\n");
    fclose(f);

    f = fopen("/spiffs/hello.txt", "r");

    if (f == NULL) {
        ESP_LOGE(MAIN, "Failed to open file for reading");
        return -1;
    }

    int bytes_read = fread(line, 1, 300, f);
    ESP_LOGI(MAIN, "bytes read: %i", bytes_read);

    printf("\n\n%s\n", line);
    fclose(f);

Output:

I (887) MAIN: Partition size: total: 173441, used: 29367
I (887) MAIN: Opening file
I (897) MAIN: bytes read: 13


Hello World!

I used esptool.py to read the flash from the esp32 and noticed something interesting.

Ran the following commands:

python3 /Users/vp/esp/Pebble_ESP32_Firmware/amazon-freertos/vendors/espressif/esp-idf/components/esptool_py/esptool/esptool.py --port /dev/cu.SLAB_USBtoUART --baud 115200 read_flash 0x327000 0x30000 flash_conetents.bin

./mkspiffs -u . flash_conetents.bin

and the hello.txt I made in code had weird byte values and its hex was:
EFBFBDEF BFBD3DEF BFBDEFBF BD7F0000 EFBFBD73 EFBFBD6A EFBFBD

but the other files, like foo.txt unloaded and were the as when they were flashed.

9

Solution

Got it working! Make sure you have the following sdkconfig option:

CONFIG_SPIFFS_META_LENGTH=4

mine was 0 and did not work.