static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index) { BDRVQcowState *s = bs->opaque; int min_index; uint64_t old_l2_offset; uint64_t *l2_table, l2_offset; old_l2_offset = s->l1_table[l1_index]; /* allocate a new l2 entry */ l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t)); if (l2_offset < 0) { return NULL; } /* update the L1 entry */ s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED; if (write_l1_entry(s, l1_index) < 0) { return NULL; } /* allocate a new entry in the l2 cache */ min_index = l2_cache_new_entry(bs); l2_table = s->l2_cache + (min_index << s->l2_bits); if (old_l2_offset == 0) { /* if there was no old l2 table, clear the new table */ memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); } else { /* if there was an old l2 table, read it from the disk */ if (bdrv_pread(s->hd, old_l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != s->l2_size * sizeof(uint64_t)) return NULL; } /* write the l2 table to the file */ if (bdrv_pwrite(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != s->l2_size * sizeof(uint64_t)) return NULL; /* update the l2 cache entry */ s->l2_cache_offsets[min_index] = l2_offset; s->l2_cache_counts[min_index] = 1; return l2_table; }
static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index) { BDRVQcowState *s = bs->opaque; int min_index; uint64_t old_l2_offset; uint64_t *l2_table, l2_offset; old_l2_offset = s->l1_table[l1_index];   l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t)); if (l2_offset < 0) { return NULL; }   s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED; if (write_l1_entry(s, l1_index) < 0) { return NULL; }   min_index = l2_cache_new_entry(bs); l2_table = s->l2_cache + (min_index << s->l2_bits); if (old_l2_offset == 0) {   memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); } else {   if (bdrv_pread(s->hd, old_l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != s->l2_size * sizeof(uint64_t)) return NULL; }   if (bdrv_pwrite(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != s->l2_size * sizeof(uint64_t)) return NULL;   s->l2_cache_offsets[min_index] = l2_offset; s->l2_cache_counts[min_index] = 1; return l2_table; }