From mboxrd@z Thu Jan 1 00:00:00 1970 From: Minchan Kim Subject: [PATCH 6/6] virtio-blk: Emulate Flush/FUA Date: Wed, 21 Dec 2011 10:00:54 +0900 Message-ID: <1324429254-28383-7-git-send-email-minchan@kernel.org> References: <1324429254-28383-1-git-send-email-minchan@kernel.org> Cc: Chris Wright , Jens Axboe , Stefan Hajnoczi , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Minchan Kim , Minchan Kim To: Rusty Russell Return-path: Received: from mail-qy0-f174.google.com ([209.85.216.174]:44470 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753853Ab1LUBBe (ORCPT ); Tue, 20 Dec 2011 20:01:34 -0500 In-Reply-To: <1324429254-28383-1-git-send-email-minchan@kernel.org> Sender: kvm-owner@vger.kernel.org List-ID: This patch emulates flush/fua on virtio-blk and pass xfstest on ext4. But it needs more reviews. Signed-off-by: Minchan Kim --- drivers/block/virtio_blk.c | 89 ++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 86 insertions(+), 3 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index e32c69e..6721b9d 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -12,7 +12,6 @@ #include #define PART_BITS 4 -static int use_make_request = 1; static int major; static DEFINE_IDA(vd_index_ida); @@ -77,6 +76,7 @@ struct virtblk_req u8 kind; #define VIRTIO_BLK_REQUEST 0x00 #define VIRTIO_BLK_BIO 0x01 +#define VIRTIO_BLK_BIO_FLUSH 0x02 u8 status; struct scatterlist sg[]; @@ -160,6 +160,9 @@ static void blk_done(struct virtqueue *vq) */ blk_start_queue(vblk->disk->queue); break; + case VIRTIO_BLK_BIO_FLUSH: + complete(vbr->private); + break; case VIRTIO_BLK_BIO: if (head) { tail->next = vbr; @@ -526,6 +529,59 @@ static void virtblk_add_buf_wait(struct virtio_blk *vblk, finish_wait(&vblk->queue_wait, &wait); } +static int virtblk_flush(struct virtio_blk *vblk, + struct virtblk_req *vbr, struct bio *bio) +{ + int error; + bool retry, notify; + DECLARE_COMPLETION_ONSTACK(done); + + vbr->private = &done; + vbr->next = NULL; + vbr->kind = VIRTIO_BLK_BIO_FLUSH; + + vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; + vbr->out_hdr.sector = 0; + if (bio) + vbr->out_hdr.ioprio = bio_prio(bio); + else + vbr->out_hdr.ioprio = 0; + + sg_set_buf(&vbr->sg[0], &vbr->out_hdr, sizeof(vbr->out_hdr)); + sg_set_buf(&vbr->sg[1], &vbr->status, sizeof(vbr->status)); + + spin_lock_irq(&vblk->lock); + if (virtqueue_add_buf(vblk->vq, vbr->sg, 1, 1, vbr) < 0) { + retry = true; + } else { + retry = false; + } + + notify = virtqueue_kick_prepare(vblk->vq); + spin_unlock_irq(&vblk->lock); + + if (notify && !virtblk_plugged(vblk)) + virtqueue_notify(vblk->vq); + + if (retry) + virtblk_add_buf_wait(vblk, vbr, 1, 1); + + wait_for_completion(&done); + error = virtblk_result(vbr); + return error; +} + +void bq_flush(struct bio_queue *bq) +{ + int cpu; + for_each_possible_cpu(cpu) { + struct per_cpu_bio __percpu *pcbio = per_cpu_ptr(bq->pcbio, cpu); + queue_work_on(cpu, + virtblk_wq, &pcbio->dwork.work); + flush_work_sync(&pcbio->dwork.work); + } +} + bool full_segment(struct per_cpu_bio __percpu *pcbio, struct bio *bio, unsigned int max) { @@ -616,9 +672,36 @@ static void virtblk_make_request(struct request_queue *q, struct bio *bio) { struct virtio_blk *vblk = q->queuedata; struct per_cpu_bio __percpu *pcbio; + bool pre_flush, post_flush; BUG_ON(bio->bi_phys_segments + 2 > vblk->sg_elems); - BUG_ON(bio->bi_rw & (REQ_FLUSH | REQ_FUA)); + + pre_flush = bio->bi_rw & REQ_FLUSH; + post_flush = bio->bi_rw & REQ_FUA; + + if (pre_flush) { + struct virtblk_req *dummy_vbr; + bq_flush(&vblk->bq); + + dummy_vbr = alloc_virtblk_req(vblk, GFP_NOIO); + virtblk_flush(vblk, dummy_vbr, NULL); + mempool_free(dummy_vbr, vblk->pool); + + if (bio->bi_sector && post_flush) { + int error; + struct virtblk_req *vbr; + vbr = alloc_virtblk_req(vblk, GFP_NOIO); + error = virtblk_flush(vblk, vbr, bio); + mempool_free(vbr, vblk->pool); + + dummy_vbr = alloc_virtblk_req(vblk, GFP_NOIO); + virtblk_flush(vblk, dummy_vbr, NULL); + mempool_free(dummy_vbr, vblk->pool); + + bio_endio(bio, error); + return; + } + } retry: preempt_disable(); pcbio = this_cpu_ptr(vblk->bq.pcbio); @@ -918,7 +1001,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) vblk->index = index; /* configure queue flush support */ - if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH) && !use_make_request) + if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) blk_queue_flush(q, REQ_FLUSH); /* If disk is read-only in the host, the guest should obey */ -- 1.7.6.4