ISFS_CommitSuperblock.c

/* this computations are repeated thoughout the function */
static inline u32 _blockClusters(FSISFS_Volume *isfs) {
    return isfs->devCaps.blockSize >> 0xe;
}
static inline u32 _superblockCount(FSISFS_Volume *isfs) {
    return 1 << isfs->superblockCountLog2;
}
static inline u8 _superblockSizeLog2(FSISFS_Volume *isfs) {
    return isfs->metadataSizeLog2 - isfs->superblockCountLog2;
}
static inline u32 _superblockClusters(FSISFS_Volume *isfs) {
    return 1 << (_superblockSizeLog2(isfs) - 0xe);
}
static inline u32 _metadataAreaStartCluster(FSISFS_Volume *isfs) {
    return isfs->fsOffset + (isfs->dataAreaSize >> 0xe);
}
static inline u32 _nextSuperblockSlot(FSISFS_Volume *isfs) {
    isfs->superblockSlot = (isfs->superblockSlot + 1) & _superblockCount(isfs);
}

int ISFS_CommitSuperblock(FSISFS_Volume *isfs)
{
    int rc = 0;
    
    if ((isfs->initState & 0x44) == 0x44) {
        return -0x80017;
    }

    isfs->super.generation++;

    for (u32 index = 0; index < _superblockCount(isfs); index++, _nextSuperblockSlot(isfs)) {
        /* get superblock cluster (the *actual* code is more complex and redundant, but should have the same result) */
        u32 superblockCluster = _metadataAreaStartCluster(isfs) + _superblockClusters(isfs) * isfs->superblockSlot;

        /* check if the superblock slot contains bad blocks */
        BOOL slotGood = TRUE;
        for (u16 clusOffs = 0; clusOffs < _superblockClusters(isfs); clusOffs += _blockClusters(isfs))
            if (isfs->super.fat[superblockCluster + clusOffs] != 0xfffc) {
                slotGood = FALSE;

        /* do not write to this slot */
        if (!slotGood)
            continue;

        /* set hmac seed */
        *(uint *)(isfs->hmacSeedBuf + 0x10) = superblockCluster

        /* write slot clusters */
        rc = ISFS_WriteCluster(isfs, superblockCluster & 0xffff, _superblockClusters(isfs), 6, isfs->hmacSeedBuf, isfs, NULL);
        if (rc == 0) {
            break;
        }

        if (rc == -0x80470) {
            /* write failed and blocks should be marked as bad */
            ISFS_SyslogWrite("ISFS: %s(%d)Detected bad logical block at %d (slot %d).Will never reuse this slot.\n",
                "fs_fat.c", 0x34d, superblockCluster, isfs->superblockSlot);
            ISFS_DebugWrite("ISFS: %s(%d) Detected bad logical block at %d (slot %d).Will never reuse this slot.\n"
                "fs_fat.c", 0x34d, superblockCluster, isfs->superblockSlot);

            /* mark the slot blocks as bad */
            for (u16 clusOffs = 0; clusOffs < _superblockClusters(isfs); clusOffs += _blockClusters(isfs))
                for (u16 clusIdx = 0; clusIdx < _blockClusters(isfs); clusIdx++)
                    isfs->super.fat[superblockCluster + clusOffs + clusIdx] = 0xfffd;

            /* ensure the next slot will be loaded instead */
            isfs->super.generation++;
        } else {
            /* other error */
            ISFS_SyslogWrite("ISFS: %s(%d)Could not write FAT blocks at %d (slot %d).rc=%d\n",
                "fs_fat.c", 0x356, superblockCluster, isfs->superblockSlot, rc);
            ISFS_DebugWrite("ISFS: %s(%d) Could not write FAT blocks at %d (slot %d).rc=%d\n",
                "fs_fat.c", 0x356, superblockCluster, isfs->superblockSlot, rc);
        }
    }

    /* not a single slot was successfully writable */
    if (index == _superblockCount(isfs)) {
        ISFS_SyslogWrite("ISFS: The flash is corrupted beyond use\n");
        ISFS_DebugWrite("ISFS: %s(%d)The flash is corrupted beyond use\n","fs_fat.c",0x364);
        return = -0x8001b;
    }

    return rc;
}