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stm32/main: Check block 0 and 1 when auto-detecting littlefs. 

The superblock for littlefs is in block 0 and 1, but block 0 may be erased
or partially written, so block 1 must be checked if block 0 does not have a
valid littlefs superblock in it.

Prior to this commit, if block 0 did not contain a valid littlefs
superblock (but block 1 did) then the auto-detection would fail, mounting a
FAT filesystem would also fail, and the system would reformat the flash,
even though it may have contained a valid littlefs filesystem.  This is now
fixed.

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2021-01-28 13:13:09 +11:00
parent 71ea438561
commit d1945cc2b5
1 changed files with 25 additions and 21 deletions
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46
ports/stm32/main.c
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@ -168,31 +168,35 @@ MP_NOINLINE STATIC bool init_flash_fs(uint reset_mode) {
#if MICROPY_VFS_LFS1 || MICROPY_VFS_LFS2 #if MICROPY_VFS_LFS1 || MICROPY_VFS_LFS2
// Try to detect the block device used for the main filesystem, based on the first block // Try to detect the block device used for the main filesystem based on the
// contents of the superblock, which can be the first or second block.
uint8_t buf[64];
ret = storage_readblocks_ext(buf, 0, 0, sizeof(buf));
mp_int_t len = -1; mp_int_t len = -1;
uint8_t buf[64];
for (size_t block_num = 0; block_num <= 1; ++block_num) {
ret = storage_readblocks_ext(buf, block_num, 0, sizeof(buf));
#if MICROPY_VFS_LFS1 #if MICROPY_VFS_LFS1
if (ret == 0 && memcmp(&buf[40], "littlefs", 8) == 0) { if (ret == 0 && memcmp(&buf[40], "littlefs", 8) == 0) {
// LFS1 // LFS1
lfs1_superblock_t *superblock = (void *)&buf[12]; lfs1_superblock_t *superblock = (void *)&buf[12];
uint32_t block_size = lfs1_fromle32(superblock->d.block_size); uint32_t block_size = lfs1_fromle32(superblock->d.block_size);
uint32_t block_count = lfs1_fromle32(superblock->d.block_count); uint32_t block_count = lfs1_fromle32(superblock->d.block_count);
len = block_count * block_size; len = block_count * block_size;
} break;
#endif }
#endif
#if MICROPY_VFS_LFS2 #if MICROPY_VFS_LFS2
if (ret == 0 && memcmp(&buf[8], "littlefs", 8) == 0) { if (ret == 0 && memcmp(&buf[8], "littlefs", 8) == 0) {
// LFS2 // LFS2
lfs2_superblock_t *superblock = (void *)&buf[20]; lfs2_superblock_t *superblock = (void *)&buf[20];
uint32_t block_size = lfs2_fromle32(superblock->block_size); uint32_t block_size = lfs2_fromle32(superblock->block_size);
uint32_t block_count = lfs2_fromle32(superblock->block_count); uint32_t block_count = lfs2_fromle32(superblock->block_count);
len = block_count * block_size; len = block_count * block_size;
break;
}
#endif
} }
#endif
if (len != -1) { if (len != -1) {
// Detected a littlefs filesystem so create correct block device for it // Detected a littlefs filesystem so create correct block device for it