Cases beyond the end of the disk image are only implemented for block
drivers that do not provide .bdrv_co_is_allocated(). It's worth making
these cases generic so that block drivers that do implement
.bdrv_co_is_allocated() also get them for free.
Suggested-by: Mark Wu
Signed-off-by: Stefan Hajnoczi
---
block.c | 26 ++
1 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/block.c b/block.c
index 4310eb5..1e468a7 100644
--- a/block.c
+++ b/block.c
@@ -2117,23 +2117,33 @@ typedef struct BdrvCoIsAllocatedData {
* not implementing the functionality are assumed to not support backing files,
* hence all their sectors are reported as allocated.
*
+ * If 'sector_num' is beyond the end of the disk image the return value is 0
+ * and 'pnum' is set to 0.
+ *
* 'pnum' is set to the number of sectors (including and immediately following
* the specified sector) that are known to be in the same
* allocated/unallocated state.
*
- * 'nb_sectors' is the max value 'pnum' should be set to.
+ * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes
+ * beyond the end of the disk image it will be clamped.
*/
int coroutine_fn bdrv_co_is_allocated(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
+int64_t n;
+
+if (sector_num >= bs->total_sectors) {
+*pnum = 0;
+return 0;
+}
+
+n = bs->total_sectors - sector_num;
+if (n < nb_sectors) {
+nb_sectors = n;
+}
+
if (!bs->drv->bdrv_co_is_allocated) {
-int64_t n;
-if (sector_num >= bs->total_sectors) {
-*pnum = 0;
-return 0;
-}
-n = bs->total_sectors - sector_num;
-*pnum = (n < nb_sectors) ? (n) : (nb_sectors);
+*pnum = nb_sectors;
return 1;
}
--
1.7.7.3
