diff options
| -rw-r--r-- | block/parallels.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/block/parallels.c b/block/parallels.c index 4173b3f..90acf79 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -192,8 +192,7 @@ static int64_t allocate_clusters(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum) { BDRVParallelsState *s = bs->opaque; - uint32_t idx, to_allocate, i; - int64_t pos, space; + int64_t pos, space, idx, to_allocate, i; pos = block_status(s, sector_num, nb_sectors, pnum); if (pos > 0) { @@ -201,11 +200,19 @@ static int64_t allocate_clusters(BlockDriverState *bs, int64_t sector_num, } idx = sector_num / s->tracks; - if (idx >= s->bat_size) { - return -EINVAL; - } - to_allocate = DIV_ROUND_UP(sector_num + *pnum, s->tracks) - idx; + + /* This function is called only by parallels_co_writev(), which will never + * pass a sector_num at or beyond the end of the image (because the block + * layer never passes such a sector_num to that function). Therefore, idx + * is always below s->bat_size. + * block_status() will limit *pnum so that sector_num + *pnum will not + * exceed the image end. Therefore, idx + to_allocate cannot exceed + * s->bat_size. + * Note that s->bat_size is an unsigned int, therefore idx + to_allocate + * will always fit into a uint32_t. */ + assert(idx < s->bat_size && idx + to_allocate <= s->bat_size); + space = to_allocate * s->tracks; if (s->data_end + space > bdrv_getlength(bs->file->bs) >> BDRV_SECTOR_BITS) { int ret; |