/* may free b */
static int merge_bb(struct backed_block_list *bbl,
struct backed_block *a, struct backed_block *b)
{
unsigned int block_len;
/* Block doesn't exist (possible if one block is the last block) */
if (!a || !b) {
return -EINVAL;
}
assert(a->block < b->block);
/* Blocks are of different types */
if (a->type != b->type) {
return -EINVAL;
}
/* Blocks are not adjacent */
block_len = a->len / bbl->block_size; /* rounds down */
if (a->block + block_len != b->block) {
return -EINVAL;
}
switch (a->type) {
case BACKED_BLOCK_DATA:
/* Don't support merging data for now */
return -EINVAL;
case BACKED_BLOCK_FILL:
if (a->fill.val != b->fill.val) {
return -EINVAL;
}
break;
case BACKED_BLOCK_FILE:
/* Already make sure b->type is BACKED_BLOCK_FILE */
if (strcmp(a->file.filename, b->file.filename) ||
a->file.offset + a->len != b->file.offset) {
return -EINVAL;
}
break;
case BACKED_BLOCK_FD:
if (a->fd.fd != b->fd.fd ||
a->fd.offset + a->len != b->fd.offset) {
return -EINVAL;
}
break;
}
/* Blocks are compatible and adjacent, with a before b. Merge b into a,
* and free b */
a->len += b->len;
a->next = b->next;
backed_block_destroy(b);
return 0;
}
void backed_block_list_destroy(struct backed_block_list *bbl)
{
if (bbl->data_blocks) {
struct backed_block *bb = bbl->data_blocks;
while (bb) {
struct backed_block *next = bb->next;
backed_block_destroy(bb);
bb = next;
}
}
free(bbl);
}
