Am 26.01.23 um 21:13 schrieb Stefan Hajnoczi: > When a write request is converted into a write zeroes request by the > detect-zeroes= feature, it is no longer associated with an I/O buffer. > The BDRV_REQ_REGISTERED_BUF flag doesn't make sense without an I/O > buffer and must be cleared because bdrv_co_do_pwrite_zeroes() fails with > -EINVAL when it's set. > > Fiona Ebner <f.eb...@proxmox.com> bisected and diagnosed this QEMU 7.2 > regression where writes containing zeroes to a blockdev with > discard=unmap,detect-zeroes=unmap fail. > > Buglink: https://gitlab.com/qemu-project/qemu/-/issues/1404 > Fixes: e8b6535533be ("block: add BDRV_REQ_REGISTERED_BUF request flag") > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > --- > block/io.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/block/io.c b/block/io.c > index a09a19f7a7..24a2bc42d3 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -1926,6 +1926,9 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild > *child, > if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) { > flags |= BDRV_REQ_MAY_UNMAP; > } > + > + /* Can't use optimization hint with bufferless zero write */ > + flags &= ~BDRV_REQ_REGISTERED_BUF; > } > > if (ret < 0) {
Tested-by: Fiona Ebner <f.eb...@proxmox.com> CC-ing stable, because it fixes a regression.
