diff options
| -rw-r--r-- | block.c | 28 |
1 files changed, 25 insertions, 3 deletions
diff --git a/block.c b/block.c index 18c0a8dd94..72bccb1ea0 100644 --- a/block.c +++ b/block.c @@ -2030,10 +2030,10 @@ 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, backing_length; int n, ro, open_flags; int ret = 0; - uint8_t *buf; + uint8_t *buf = NULL; char filename[PATH_MAX]; if (!drv) @@ -2058,7 +2058,29 @@ int bdrv_commit(BlockDriverState *bs) } } - total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; + length = bdrv_getlength(bs); + if (length < 0) { + ret = length; + goto ro_cleanup; + } + + backing_length = bdrv_getlength(bs->backing_hd); + if (backing_length < 0) { + ret = backing_length; + goto ro_cleanup; + } + + /* 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 > backing_length) { + 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) { |