@@ -1876,10 +1876,10 @@ int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
int bdrv_commit(BlockDriverState *bs)
{
BlockDriver *drv = bs->drv;
- int64_t sector, total_sectors;
+ int64_t sector, total_sectors, length;
int n, ro, open_flags;
int ret = 0;
- uint8_t *buf;
+ uint8_t *buf = NULL;
char filename[PATH_MAX];
if (!drv)
@@ -1904,7 +1904,19 @@ int bdrv_commit(BlockDriverState *bs)
}
}
- total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
+ length = bdrv_getlength(bs);
+
+ /* If our top snapshot is larger than the backing file image,
+ * grow the backing file image if possible. If not possible,
+ * we must return an error */
+ if (length > bdrv_getlength(bs->backing_hd)) {
+ ret = bdrv_truncate(bs->backing_hd, length);
+ if (ret < 0) {
+ goto ro_cleanup;
+ }
+ }
+
+ total_sectors = length >> BDRV_SECTOR_BITS;
buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
for (sector = 0; sector < total_sectors; sector += n) {
Currently, if an image file is logically larger than its backing file, commiting it via 'qemu-img commit' will fail. For instance, if we have a base image with a virtual size 10G, and a snapshot image of size 20G, then committing the snapshot offline with 'qemu-img commit' will likely fail. This will automatically attempt to resize the base image, if the snapshot image to be committed is larger. Signed-off-by: Jeff Cody <jcody@redhat.com> --- block.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)