When falling through to the underlying file in
bdrv_co_get_block_status(), if it returns that the query offset is
beyond the file end (by setting *pnum to 0), return the range to be
zero and do not let the number of sectors for which information could be
obtained be overwritten.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/block.c b/block.c
index 773e87e..68dc11d 100644
--- a/block.c
+++ b/block.c
@@ -3954,13 +3954,25 @@ 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)) {
+ int backing_pnum;
+
ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
- *pnum, pnum);
+ *pnum, &backing_pnum);
if (ret2 >= 0) {
/* Ignore errors. This is just providing extra information, it
* is useful but not necessary.
*/
- ret |= (ret2 & BDRV_BLOCK_ZERO);
+ if (!backing_pnum) {
+ /* !backing_pnum indicates an offset at or beyond the EOF; it
is
+ * perfectly valid for the format block driver to point to such
+ * offsets, so catch it and mark everything as unallocated and
+ * empty */
+ ret = BDRV_BLOCK_ZERO;
+ } else {
+ /* Limit request to the range reported by the protocol driver
*/
+ *pnum = backing_pnum;
+ ret |= (ret2 & BDRV_BLOCK_ZERO);
+ }
}
}
--
1.9.3
