fix(storage): FATFS WL function formatting wrong partition

Closes https://github.com/espressif/esp-idf/issues/12542

Co-authored-by: Tony Stuart <anthonyfstuart@gmail.com>

components/fatfs/test_apps/flash_wl/main/test_fatfs_flash_wl.c

@@ -60,6 +60,30 @@ TEST_CASE("(WL) can format when the FAT is mounted already", "[fatfs][wear_level
     test_teardown();
 }
 
+TEST_CASE("(WL) can format specified FAT when more are mounted", "[fatfs][wear_levelling][timeout=180]")
+{
+    esp_vfs_fat_sdmmc_mount_config_t mount_config = {
+        .format_if_mount_failed = true,
+        .max_files = 5,
+    };
+    wl_handle_t s_test_wl_handle1;
+    wl_handle_t s_test_wl_handle2;
+    TEST_ESP_OK(esp_vfs_fat_spiflash_mount_rw_wl("/spiflash1", "storage", &mount_config, &s_test_wl_handle1));
+    TEST_ESP_OK(esp_vfs_fat_spiflash_mount_rw_wl("/spiflash2", "storage2", &mount_config, &s_test_wl_handle2));
+
+    test_fatfs_create_file_with_text("/spiflash1/hello.txt", fatfs_test_hello_str);
+    test_fatfs_create_file_with_text("/spiflash2/hello.txt", fatfs_test_hello_str);
+
+    TEST_ESP_OK(esp_vfs_fat_spiflash_format_rw_wl("/spiflash2", "storage2"));
+
+    FILE* f = fopen("/spiflash2/hello.txt", "r");
+    TEST_ASSERT_NULL(f); // File is erased on the formatted FAT
+    test_fatfs_pread_file("/spiflash1/hello.txt"); // File is still readable on the other FAT
+
+    TEST_ESP_OK(esp_vfs_fat_spiflash_unmount_rw_wl("/spiflash1", s_test_wl_handle1));
+    TEST_ESP_OK(esp_vfs_fat_spiflash_unmount_rw_wl("/spiflash2", s_test_wl_handle2));
+}
+
 TEST_CASE("(WL) can create and write file", "[fatfs][wear_levelling]")
 {
     test_setup();

components/fatfs/test_apps/flash_wl/partitions.csv

@@ -1,3 +1,4 @@
 # Name,   Type, SubType, Offset,  Size, Flags
-factory,  app,  factory, 0x10000, 1M,
+factory,  app,  factory, 0x10000, 768k,
 storage,  data, fat,     ,        528k,
+storage2, data, fat,     ,        528k,

components/fatfs/vfs/vfs_fat_sdmmc.c

@@ -1,11 +1,12 @@
 /*
- * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2015-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 #include <stdlib.h>
 #include <string.h>
+#include "esp_check.h"
 #include "esp_log.h"
 #include "esp_vfs.h"
 #include "esp_vfs_fat.h"
@@ -469,7 +470,8 @@ esp_err_t esp_vfs_fat_sdcard_format(const char *base_path, sdmmc_card_t *card)
 
     //unmount
     char drv[3] = {(char)('0' + pdrv), ':', 0};
-    f_mount(0, drv, 0);
+    FRESULT res = f_mount(0, drv, 0);
+    ESP_RETURN_ON_FALSE(res != FR_INVALID_DRIVE, ESP_FAIL, TAG, "f_mount unmount failed (%d) - the logical drive number is invalid", res);
 
     //format
     uint32_t id = FF_VOLUMES;
@@ -480,7 +482,7 @@ esp_err_t esp_vfs_fat_sdcard_format(const char *base_path, sdmmc_card_t *card)
                 s_ctx[id]->mount_config.allocation_unit_size);
     ESP_LOGI(TAG, "Formatting card, allocation unit size=%d", alloc_unit_size);
     const MKFS_PARM opt = {(BYTE)FM_ANY, 0, 0, 0, alloc_unit_size};
-    FRESULT res = f_mkfs(drv, &opt, workbuf, workbuf_size);
+    res = f_mkfs(drv, &opt, workbuf, workbuf_size);
     free(workbuf);
     if (res != FR_OK) {
         ret = ESP_FAIL;

components/fatfs/vfs/vfs_fat_spiflash.c

@@ -203,7 +203,6 @@ esp_err_t esp_vfs_fat_spiflash_format_rw_wl(const char* base_path, const char* p
 
     wl_handle_t temp_handle = WL_INVALID_HANDLE;
     uint32_t id = FF_VOLUMES;
-    char drv[3] = {0, ':', 0};
 
     bool found = s_get_context_id_by_label(partition_label, &id);
     if (!found) {
@@ -219,8 +218,10 @@ esp_err_t esp_vfs_fat_spiflash_format_rw_wl(const char* base_path, const char* p
     }
 
     //unmount
-    drv[1] = (char)('0' + s_ctx[id]->pdrv);
-    f_mount(0, drv, 0);
+    char drv[3] = {(char)('0' + s_ctx[id]->pdrv), ':', 0};
+    FRESULT fresult = f_mount(0, drv, 0);
+    ESP_RETURN_ON_FALSE(fresult != FR_INVALID_DRIVE, ESP_FAIL, TAG, "f_mount unmount failed (%d) - the logical drive number is invalid", fresult);
+    ESP_GOTO_ON_FALSE(fresult == FR_OK, ESP_FAIL, recycle, TAG, "f_mount unmount failed (%d), go to recycle", fresult);
 
     const size_t workbuf_size = 4096;
     void *workbuf = ff_memalloc(workbuf_size);
@@ -231,7 +232,7 @@ esp_err_t esp_vfs_fat_spiflash_format_rw_wl(const char* base_path, const char* p
     size_t alloc_unit_size = esp_vfs_fat_get_allocation_unit_size(CONFIG_WL_SECTOR_SIZE, s_ctx[id]->mount_config.allocation_unit_size);
     ESP_LOGI(TAG, "Formatting FATFS partition, allocation unit size=%d", alloc_unit_size);
     const MKFS_PARM opt = {(BYTE)(FM_ANY | FM_SFD), 0, 0, 0, alloc_unit_size};
-    FRESULT fresult = f_mkfs(drv, &opt, workbuf, workbuf_size);
+    fresult = f_mkfs(drv, &opt, workbuf, workbuf_size);
     free(workbuf);
     workbuf = NULL;
     ESP_GOTO_ON_FALSE(fresult == FR_OK, ESP_FAIL, mount_back, TAG, "f_mkfs failed (%d)", fresult);