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authorStefan Hajnoczi <stefanha@linux.vnet.ibm.com>2011-11-29 13:49:51 +0000
committerKevin Wolf <kwolf@redhat.com>2011-12-05 14:51:39 +0100
commitbd9533e36ea3d6c964f65b8e407bad00dab59e5d (patch)
tree188ed325e113e99cf4921ccdba1affe0e3f453b6
parentc57c465800a9d193f9b41c97dbbbb6cd4fb08ff6 (diff)
downloadqemu-arm-bd9533e36ea3d6c964f65b8e407bad00dab59e5d.tar.gz
block: implement bdrv_co_is_allocated() boundary cases
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 <wudxw@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block.c26
1 files changed, 18 insertions, 8 deletions
diff --git a/block.c b/block.c
index dd5d5ca4d2..ecc5b442d4 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;
}