Hi Ming,
I wrote this against your devel-v3 branch. I'm wondering if you plan to
send a new version of the kernel patch soon? From the latest
discussions, I don't think there were major issues found on review. :)
I hope people don't mind I cc'd linux-block about this userspace code.
Please, let me know if I shouldn't do that.
-- >8 --
The number of sectors read/written is used to verify forward progress of
the request inside the kernel. If we return 0 here, the kernel
understands that as an IO failure (see first check in ubd_complete_rq),
and will reissue the request, causing an infinite loop of unfullfilled
requests. This can be reproduced with:
ubdsrv/ubd add -t null -n0 -q1 -d1
dd if=/dev/vda of=/dev/ubdb0 count=1 bs=4k
The approach minics nullblk, which returns the total IO size.
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
---
tgt_null.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tgt_null.c b/tgt_null.c
index 85636c405f0c..61850a2cd046 100644
--- a/tgt_null.c
+++ b/tgt_null.c
@@ -20,7 +20,9 @@ static int null_init_tgt(struct ubdsrv_tgt_info *tgt, int type, int argc,
static int null_handle_io_async(struct ubdsrv_queue *q, struct ubd_io *io,
int tag)
{
- ubdsrv_mark_io_done(io, 0);
+ const struct ubdsrv_io_desc *iod = ubdsrv_get_iod(q, tag);
+
+ ubdsrv_mark_io_done(io, iod->nr_sectors << 9);
return 0;
}
--
2.36.1
