From: Jeff Moyer <jmoyer@redhat.com> [ Upstream commit 96222d53842dfe54869ec4e1b9d4856daf9105a2 ] fstests generic/471 reports a failure when run with MOUNT_OPTIONS="-o dax". The reason is that the initial pwrite to an empty file with the RWF_NOWAIT flag set does not return -EAGAIN. It turns out that dax_iomap_rw doesn't pass that flag through to iomap_apply. With this patch applied, generic/471 passes for me. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/x49r1z86e1d.fsf@segfault.boston.devel.redhat.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- fs/dax.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/dax.c b/fs/dax.c index e6b566d..366239a 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1298,6 +1298,9 @@ int __dax_zero_page_range(struct block_device *bdev, lockdep_assert_held(&inode->i_rwsem); } + if (iocb->ki_flags & IOCB_NOWAIT) + flags |= IOMAP_NOWAIT; + while (iov_iter_count(iter)) { ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, iter, dax_iomap_actor); -- 1.8.3