Solved
LittleFS dir fetch unexpected values in test parameter. STM32
Hello everyone,
I am using an STM32 microcontroller and I am facing a problem when I try to mount an external flash memory. The problem is inside the function lfs_dir_fetch which is returning unexpected values in the test buffer here:
struct lfs_disk_dir test;
int err = lfs_bd_read(lfs, tpair[i], 0, &test, sizeof(test));
lfs_dir_fromle32(&test);
the returned values are:
Invalid size: test.size = 335610112, block_size = 40960
Invalid size: test.size = 335610112, block_size = 40960
lfs error:495: Corrupted dir pair at 0 1
lfs error:2214: Invalid superblock at 0 1
(*)Error in mounting external flash memory
I have successfully communicate with the external flash, since I am able to read its manufacture ID. I have also configured properly the littlefs function and I test them by writing raw data to the external flash and I was able to receive them correctly. I cannot understand what is the test variable that is being declared and why I cannot proceed to the the calculation of the crc parameter since it has a continue statement inside the problematic block:
static int lfs_dir_fetch(lfs_t *lfs,
lfs_dir_t *dir, const lfs_block_t pair[2]) {
// copy out pair, otherwise may be aliasing dir
const lfs_block_t tpair[2] = {pair[0], pair[1]};
bool valid = false;
// check both blocks for the most recent revision
for (int i = 0; i < 2; i++) {
struct lfs_disk_dir test;
int err = lfs_bd_read(lfs, tpair[i], 0, &test, sizeof(test));
lfs_dir_fromle32(&test);
if (err) {
if (err == LFS_ERR_CORRUPT) {
continue;
}
return err;
}
if (valid && lfs_scmp(test.rev, dir->d.rev) < 0) {
continue;
}
if ((0x7fffffff & test.size) < sizeof(test)+4 ||
(0x7fffffff & test.size) > lfs->cfg->block_size) {
printf("Invalid size: test.size = %ld, block_size = %ld\n",
(0x7fffffff & test.size), lfs->cfg->block_size);
continue;
}
uint32_t crc = 0xffffffff;
lfs_dir_tole32(&test);
lfs_crc(&crc, &test, sizeof(test));
lfs_dir_fromle32(&test);
err = lfs_bd_crc(lfs, tpair[i], sizeof(test),
(0x7fffffff & test.size) - sizeof(test), &crc);
if (err) {
if (err == LFS_ERR_CORRUPT) {
continue;
}
return err;
}
if (crc != 0) {
continue;
}
valid = true;
// setup dir in case it's valid
dir->pair[0] = tpair[(i+0) % 2];
dir->pair[1] = tpair[(i+1) % 2];
dir->off = sizeof(dir->d);
dir->d = test;
}
if (!valid) {
LFS_ERROR("Corrupted dir pair at %" PRIu32 " %" PRIu32 ,
tpair[0], tpair[1]);
return LFS_ERR_CORRUPT;
}
return 0;
}