block: look for zero blocks in bs->file

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Paolo Bonzini 2013-09-04 19:00:38 +02:00 committed by Stefan Hajnoczi
parent 918e92d71b
commit 5daa74a6eb
1 changed files with 15 additions and 1 deletions

16
block.c
View File

@ -3075,7 +3075,7 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
{
int64_t length;
int64_t n;
int64_t ret;
int64_t ret, ret2;
length = bdrv_getlength(bs);
if (length < 0) {
@ -3117,6 +3117,20 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
}
}
}
if (bs->file &&
(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
(ret & BDRV_BLOCK_OFFSET_VALID)) {
ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
*pnum, pnum);
if (ret2 >= 0) {
/* Ignore errors. This is just providing extra information, it
* is useful but not necessary.
*/
ret |= (ret2 & BDRV_BLOCK_ZERO);
}
}
return ret;
}