For an O_DIRECT request to succeed, it's not only necessary that all base addresses in the qiov are aligned, but also that each lengh in it is aligned.
Signed-off-by: Kevin Wolf <kw...@redhat.com> --- block.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/block.c b/block.c index 382ea71..613201b 100644 --- a/block.c +++ b/block.c @@ -4349,6 +4349,9 @@ bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) if ((uintptr_t) qiov->iov[i].iov_base % bs->buffer_alignment) { return false; } + if (qiov->iov[i].iov_len % bs->buffer_alignment) { + return false; + } } return true; -- 1.8.1.4