[PATCH] nvmet: avoid unnecessary fsync and flush bio
Christoph Hellwig
hch at lst.de
Fri Jul 22 08:06:35 PDT 2022
On Fri, Jul 22, 2022 at 08:12:24PM +0800, Guixin Liu wrote:
> @@ -333,10 +333,16 @@ static void nvmet_bdev_execute_rw(struct nvmet_req *req)
> static void nvmet_bdev_execute_flush(struct nvmet_req *req)
> {
> struct bio *bio = &req->b.inline_bio;
> + struct request_queue *q = req->ns->bdev->bd_queue;
>
> if (!nvmet_check_transfer_len(req, 0))
> return;
>
> + if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
This should be using a bdev_write_cache.
But more importantly: if the backend does not have a volatile write
cache, and we should not even receive flushes from the remote side.
> + if (req->ns->buffered_io)
> + return errno_to_nvme_status(req, vfs_fsync(req->ns->file, 1));
> + else
> + return errno_to_nvme_status(req, 0);
No need for the else, and the simple success case can just use the
constant status and does not need a translation.
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