Am 02.04.2014 15:44, schrieb Paolo Bonzini: > Max WRITE SAME length is also used when the UNMAP bit is zero, so it > should be queried even if LBPWS=0. Same for the optimal transfer > length. > > However, the write_zeroes_alignment only matters for UNMAP=1 so we > still restrict it to LBPWS=1. > > Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> > --- > block/iscsi.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/block/iscsi.c b/block/iscsi.c > index 00316af..bb88b4b 100644 > --- a/block/iscsi.c > +++ b/block/iscsi.c > @@ -1335,18 +1335,20 @@ static int iscsi_refresh_limits(BlockDriverState *bs) > > /* We don't actually refresh here, but just return data queried in > * iscsi_open(): iscsi targets don't change their limits. */ > - if (iscsilun->lbp.lbpu || iscsilun->lbp.lbpws) { > + if (iscsilun->lbp.lbpu) { > if (iscsilun->bl.max_unmap < 0xffffffff) { > bs->bl.max_discard = sector_lun2qemu(iscsilun->bl.max_unmap, > iscsilun); > } > bs->bl.discard_alignment = > sector_lun2qemu(iscsilun->bl.opt_unmap_gran, > iscsilun); > + } > > - if (iscsilun->bl.max_ws_len < 0xffffffff) { > - bs->bl.max_write_zeroes = > sector_lun2qemu(iscsilun->bl.max_ws_len, > - iscsilun); > - } > + if (iscsilun->bl.max_ws_len < 0xffffffff) { > + bs->bl.max_write_zeroes = sector_lun2qemu(iscsilun->bl.max_ws_len, > + iscsilun); > + } > + if (iscsilun->lbp.lbpws) { > bs->bl.write_zeroes_alignment = > sector_lun2qemu(iscsilun->bl.opt_unmap_gran, > iscsilun); > }
Reviewed-by: Peter Lieven <p...@kamp.de> PS: One thing that came into my mind while looking at this. If a target has LBPWS == 0 and we send a write zeroes request with BDRV_REQ_MAY_UNMAP we fail with -ENOTSUP. Shouldn't we fall back to WRITESAME without UNMAP if iscsilun->has_write_same == true? Peter