vhost-user-blk: add discard/write zeroes features support (caa1ee43) · Commits · SUMMER2020 / students / proj-2021291

contrib/vhost-user-blk/vhost-user-blk.c

+107 −33

Original line number	Diff line number	Diff line
		@@ -63,6 +63,20 @@ static size_t vub_iov_size(const struct iovec *iov,
		return len;
		}

		static size_t vub_iov_to_buf(const struct iovec *iov,
		const unsigned int iov_cnt, void *buf)
		{
		size_t len;
		unsigned int i;

		len = 0;
		for (i = 0; i < iov_cnt; i++) {
		memcpy(buf + len, iov[i].iov_base, iov[i].iov_len);
		len += iov[i].iov_len;
		}
		return len;
		}

		static void vub_panic_cb(VuDev vu_dev, const char buf)
		{
		VugDev *gdev;
		@@ -161,6 +175,44 @@ vub_writev(VubReq req, struct iovec iov, uint32_t iovcnt)
		return rc;
		}

		static int
		vub_discard_write_zeroes(VubReq req, struct iovec iov, uint32_t iovcnt,
		uint32_t type)
		{
		struct virtio_blk_discard_write_zeroes *desc;
		ssize_t size;
		void *buf;

		size = vub_iov_size(iov, iovcnt);
		if (size != sizeof(*desc)) {
		fprintf(stderr, "Invalid size %ld, expect %ld\n", size, sizeof(*desc));
		return -1;
		}
		buf = g_new0(char, size);
		vub_iov_to_buf(iov, iovcnt, buf);

		#if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
		VubDev *vdev_blk = req->vdev_blk;
		desc = (struct virtio_blk_discard_write_zeroes *)buf;
		uint64_t range[2] = { le64toh(desc->sector) << 9,
		le32toh(desc->num_sectors) << 9 };
		if (type == VIRTIO_BLK_T_DISCARD) {
		if (ioctl(vdev_blk->blk_fd, BLKDISCARD, range) == 0) {
		g_free(buf);
		return 0;
		}
		} else if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
		if (ioctl(vdev_blk->blk_fd, BLKZEROOUT, range) == 0) {
		g_free(buf);
		return 0;
		}
		}
		#endif

		g_free(buf);
		return -1;
		}

		static void
		vub_flush(VubReq *req)
		{
		@@ -216,8 +268,9 @@ static int vub_virtio_process_req(VubDev *vdev_blk,
		in_num--;

		type = le32toh(req->out->type);
		switch (type & ~(VIRTIO_BLK_T_OUT \| VIRTIO_BLK_T_BARRIER)) {
		case VIRTIO_BLK_T_IN: {
		switch (type & ~VIRTIO_BLK_T_BARRIER) {
		case VIRTIO_BLK_T_IN:
		case VIRTIO_BLK_T_OUT: {
		ssize_t ret = 0;
		bool is_write = type & VIRTIO_BLK_T_OUT;
		req->sector_num = le64toh(req->out->sector);
		@@ -234,12 +287,11 @@ static int vub_virtio_process_req(VubDev *vdev_blk,
		vub_req_complete(req);
		break;
		}
		case VIRTIO_BLK_T_FLUSH: {
		case VIRTIO_BLK_T_FLUSH:
		vub_flush(req);
		req->in->status = VIRTIO_BLK_S_OK;
		vub_req_complete(req);
		break;
		}
		case VIRTIO_BLK_T_GET_ID: {
		size_t size = MIN(vub_iov_size(&elem->in_sg[0], in_num),
		VIRTIO_BLK_ID_BYTES);
		@@ -249,11 +301,22 @@ static int vub_virtio_process_req(VubDev *vdev_blk,
		vub_req_complete(req);
		break;
		}
		default: {
		req->in->status = VIRTIO_BLK_S_UNSUPP;
		case VIRTIO_BLK_T_DISCARD:
		case VIRTIO_BLK_T_WRITE_ZEROES: {
		int rc;
		rc = vub_discard_write_zeroes(req, &elem->out_sg[1], out_num, type);
		if (rc == 0) {
		req->in->status = VIRTIO_BLK_S_OK;
		} else {
		req->in->status = VIRTIO_BLK_S_IOERR;
		}
		vub_req_complete(req);
		break;
		}
		default:
		req->in->status = VIRTIO_BLK_S_UNSUPP;
		vub_req_complete(req);
		break;
		}

		return 0;
		@@ -317,6 +380,10 @@ vub_get_features(VuDev *dev)
		1ull << VIRTIO_BLK_F_TOPOLOGY \|
		1ull << VIRTIO_BLK_F_BLK_SIZE \|
		1ull << VIRTIO_BLK_F_FLUSH \|
		#if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
		1ull << VIRTIO_BLK_F_DISCARD \|
		1ull << VIRTIO_BLK_F_WRITE_ZEROES \|
		#endif
		1ull << VIRTIO_BLK_F_CONFIG_WCE \|
		1ull << VIRTIO_F_VERSION_1 \|
		1ull << VHOST_USER_F_PROTOCOL_FEATURES;
		@@ -478,6 +545,13 @@ vub_initialize_config(int fd, struct virtio_blk_config *config)
		config->min_io_size = 1;
		config->opt_io_size = 1;
		config->num_queues = 1;
		#if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
		config->max_discard_sectors = 32768;
		config->max_discard_seg = 1;
		config->discard_sector_alignment = config->blk_size >> 9;
		config->max_write_zeroes_sectors = 32768;
		config->max_write_zeroes_seg = 1;
		#endif
		}

		static VubDev *

hw/block/vhost-user-blk.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -38,6 +38,8 @@ static const int user_feature_bits[] = {
		VIRTIO_BLK_F_RO,
		VIRTIO_BLK_F_FLUSH,
		VIRTIO_BLK_F_CONFIG_WCE,
		VIRTIO_BLK_F_DISCARD,
		VIRTIO_BLK_F_WRITE_ZEROES,
		VIRTIO_F_VERSION_1,
		VIRTIO_RING_F_INDIRECT_DESC,
		VIRTIO_RING_F_EVENT_IDX,
		@@ -204,6 +206,8 @@ static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
		virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
		virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
		virtio_add_feature(&features, VIRTIO_BLK_F_RO);
		virtio_add_feature(&features, VIRTIO_BLK_F_DISCARD);
		virtio_add_feature(&features, VIRTIO_BLK_F_WRITE_ZEROES);

		if (s->config_wce) {
		virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);

include/standard-headers/linux/virtio_blk.h

+48 −0

Original line number	Diff line number	Diff line
		@@ -38,6 +38,8 @@
		#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
		#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
		#define VIRTIO_BLK_F_MQ 12 /* support more than one vq */
		#define VIRTIO_BLK_F_DISCARD 13 /* DISCARD is supported */
		#define VIRTIO_BLK_F_WRITE_ZEROES 14 /* WRITE ZEROES is supported */

		/* Legacy feature bits */
		#ifndef VIRTIO_BLK_NO_LEGACY
		@@ -84,6 +86,39 @@ struct virtio_blk_config {

		/* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
		uint16_t num_queues;

		/* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */
		/*
		* The maximum discard sectors (in 512-byte sectors) for
		* one segment.
		*/
		uint32_t max_discard_sectors;
		/*
		* The maximum number of discard segments in a
		* discard command.
		*/
		uint32_t max_discard_seg;
		/* Discard commands must be aligned to this number of sectors. */
		uint32_t discard_sector_alignment;

		/* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */
		/*
		* The maximum number of write zeroes sectors (in 512-byte sectors) in
		* one segment.
		*/
		uint32_t max_write_zeroes_sectors;
		/*
		* The maximum number of segments in a write zeroes
		* command.
		*/
		uint32_t max_write_zeroes_seg;
		/*
		* Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the
		* deallocation of one or more of the sectors.
		*/
		uint8_t write_zeroes_may_unmap;

		uint8_t unused1[3];
		} QEMU_PACKED;

		/*
		@@ -137,6 +172,19 @@ struct virtio_blk_outhdr {
		__virtio64 sector;
		};

		/* Unmap this range (only valid for write zeroes command) */
		#define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001

		/* Discard/write zeroes range for each request. */
		struct virtio_blk_discard_write_zeroes {
		/* discard/write zeroes start sector */
		uint64_t sector;
		/* number of discard/write zeroes sectors */
		uint32_t num_sectors;
		/* flags for this range */
		uint32_t flags;
		};

		#ifndef VIRTIO_BLK_NO_LEGACY
		struct virtio_scsi_inhdr {
		__virtio32 errors;