We don't know if fallocate really supports FALLOC_FL_PUNCH_HOLE till fallocate is called. If it doesn't support, loop will return -EOPNOTSUPP and we seee a lot of error message printed by blk_update_request. Failure for discard IO isn't a problem, so we just return 0 in loop which will suppress the IO error message Signed-off-by: Shaohua Li <shli@xxxxxx> --- drivers/block/loop.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index a30aa45..15f51e3 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -441,6 +441,9 @@ static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos) ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq)); if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP)) ret = -EIO; + + if (req_op(rq) == REQ_OP_DISCARD && ret == -EOPNOTSUPP) + ret = 0; out: return ret; } -- 2.9.5
