file-posix.c was taking a 64-bit bytes in raw_co_copy_range_to(), passing it through a 32-bit parameter of paio_submit_co_full(), then widening it back to size_t when assigning into acb->aio_nbytes.
Looking at io.c, I can't quickly tell if bdrv_co_copy_range_internal() is fragmenting things to honor bs->bl.max_transfer, or if it can accidentally send requests larger than 2G down to the driver. If the former, then this is a no-op; if the latter, then someone needs to find a way to trigger this assertion and patch the block layer to properly fragment copy_range requests. Either way, we're better off with an assertion than the risk of silent data corruption. Signed-off-by: Eric Blake <ebl...@redhat.com> --- block/file-posix.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 58c86a01eaa..48ad3bb372a 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1821,7 +1821,7 @@ static int aio_worker(void *arg) static int paio_submit_co_full(BlockDriverState *bs, int fd, int64_t offset, int fd2, int64_t offset2, QEMUIOVector *qiov, - int bytes, int type) + uint64_t bytes, int type) { RawPosixAIOData *acb = g_new(RawPosixAIOData, 1); ThreadPool *pool; @@ -1832,6 +1832,7 @@ static int paio_submit_co_full(BlockDriverState *bs, int fd, acb->aio_fd2 = fd2; acb->aio_offset2 = offset2; + assert(bytes <= SIZE_MAX); acb->aio_nbytes = bytes; acb->aio_offset = offset; @@ -1848,7 +1849,7 @@ static int paio_submit_co_full(BlockDriverState *bs, int fd, static inline int paio_submit_co(BlockDriverState *bs, int fd, int64_t offset, QEMUIOVector *qiov, - int bytes, int type) + uint64_t bytes, int type) { return paio_submit_co_full(bs, fd, offset, -1, 0, qiov, bytes, type); } -- 2.17.2