Add VIRTIO_BLK_T_DISCARD support to the virtio-blk driver
If the hypervisor advertises support for the DISCARD command then the guest can perform TRIM commands, freeing space on the backing store. If VIRTIO_BLK_F_DISCARD is enabled, advertise DISKFLAG_CANDELETE Tested with FreeBSD guests on bhyve and KVM Reviewed by: jhb Tested by: freqlabs MFC after: 1 month Relnotes: yes Sponsored by: Klara Inc. Differential Revision: https://reviews.freebsd.org/D21708
This commit is contained in:
Allan Jude
parent
d272016da4
commit
2cc8a524af
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=363255
@ -81,6 +81,7 @@ struct vtblk_softc {
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#define VTBLK_FLAG_SUSPEND 0x0008
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#define VTBLK_FLAG_BARRIER 0x0010
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#define VTBLK_FLAG_WC_CONFIG 0x0020
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#define VTBLK_FLAG_DISCARD 0x0040
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struct virtqueue *vtblk_vq;
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struct sglist *vtblk_sglist;
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@ -112,6 +113,7 @@ static struct virtio_feature_desc vtblk_feature_desc[] = {
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{ VIRTIO_BLK_F_WCE, "WriteCache" },
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{ VIRTIO_BLK_F_TOPOLOGY, "Topology" },
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{ VIRTIO_BLK_F_CONFIG_WCE, "ConfigWCE" },
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{ VIRTIO_BLK_F_DISCARD, "Discard" },
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{ 0, NULL }
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};
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@ -210,6 +212,7 @@ TUNABLE_INT("hw.vtblk.writecache_mode", &vtblk_writecache_mode);
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VIRTIO_BLK_F_WCE | \
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VIRTIO_BLK_F_TOPOLOGY | \
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VIRTIO_BLK_F_CONFIG_WCE | \
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VIRTIO_BLK_F_DISCARD | \
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VIRTIO_RING_F_INDIRECT_DESC)
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#define VTBLK_MTX(_sc) &(_sc)->vtblk_mtx
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@ -459,7 +462,7 @@ vtblk_config_change(device_t dev)
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vtblk_read_config(sc, &blkcfg);
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/* Capacity is always in 512-byte units. */
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capacity = blkcfg.capacity * 512;
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capacity = blkcfg.capacity * VTBLK_BSIZE;
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if (sc->vtblk_disk->d_mediasize != capacity)
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vtblk_resize_disk(sc, capacity);
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@ -544,13 +547,14 @@ vtblk_strategy(struct bio *bp)
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* be a better way to report our readonly'ness to GEOM above.
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*/
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if (sc->vtblk_flags & VTBLK_FLAG_READONLY &&
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(bp->bio_cmd == BIO_WRITE || bp->bio_cmd == BIO_FLUSH)) {
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(bp->bio_cmd == BIO_WRITE || bp->bio_cmd == BIO_FLUSH ||
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bp->bio_cmd == BIO_DELETE)) {
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vtblk_bio_done(sc, bp, EROFS);
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return;
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}
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if ((bp->bio_cmd != BIO_READ) && (bp->bio_cmd != BIO_WRITE) &&
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(bp->bio_cmd != BIO_FLUSH)) {
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(bp->bio_cmd != BIO_FLUSH) && (bp->bio_cmd != BIO_DELETE)) {
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vtblk_bio_done(sc, bp, EOPNOTSUPP);
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return;
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}
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@ -563,6 +567,13 @@ vtblk_strategy(struct bio *bp)
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return;
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}
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if ((bp->bio_cmd == BIO_DELETE) &&
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!(sc->vtblk_flags & VTBLK_FLAG_DISCARD)) {
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VTBLK_UNLOCK(sc);
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vtblk_bio_done(sc, bp, EOPNOTSUPP);
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return;
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}
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bioq_insert_tail(&sc->vtblk_bioq, bp);
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vtblk_startio(sc);
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@ -598,6 +609,8 @@ vtblk_setup_features(struct vtblk_softc *sc)
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sc->vtblk_flags |= VTBLK_FLAG_BARRIER;
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if (virtio_with_feature(dev, VIRTIO_BLK_F_CONFIG_WCE))
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sc->vtblk_flags |= VTBLK_FLAG_WC_CONFIG;
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if (virtio_with_feature(dev, VIRTIO_BLK_F_DISCARD))
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sc->vtblk_flags |= VTBLK_FLAG_DISCARD;
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}
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static int
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@ -687,12 +700,12 @@ vtblk_alloc_disk(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg)
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dp->d_dump = vtblk_dump;
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/* Capacity is always in 512-byte units. */
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dp->d_mediasize = blkcfg->capacity * 512;
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dp->d_mediasize = blkcfg->capacity * VTBLK_BSIZE;
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if (virtio_with_feature(dev, VIRTIO_BLK_F_BLK_SIZE))
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dp->d_sectorsize = blkcfg->blk_size;
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else
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dp->d_sectorsize = 512;
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dp->d_sectorsize = VTBLK_BSIZE;
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/*
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* The VirtIO maximum I/O size is given in terms of segments.
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@ -726,6 +739,11 @@ vtblk_alloc_disk(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg)
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dp->d_stripesize;
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}
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if (virtio_with_feature(dev, VIRTIO_BLK_F_DISCARD)) {
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dp->d_flags |= DISKFLAG_CANDELETE;
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dp->d_delmaxsize = blkcfg->max_discard_sectors * VTBLK_BSIZE;
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}
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if (vtblk_write_cache_enabled(sc, blkcfg) != 0)
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sc->vtblk_write_cache = VTBLK_CACHE_WRITEBACK;
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else
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@ -876,11 +894,15 @@ vtblk_request_bio(struct vtblk_softc *sc)
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break;
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case BIO_READ:
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req->vbr_hdr.type = VIRTIO_BLK_T_IN;
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req->vbr_hdr.sector = bp->bio_offset / 512;
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req->vbr_hdr.sector = bp->bio_offset / VTBLK_BSIZE;
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break;
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case BIO_WRITE:
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req->vbr_hdr.type = VIRTIO_BLK_T_OUT;
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req->vbr_hdr.sector = bp->bio_offset / 512;
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req->vbr_hdr.sector = bp->bio_offset / VTBLK_BSIZE;
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break;
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case BIO_DELETE:
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req->vbr_hdr.type = VIRTIO_BLK_T_DISCARD;
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req->vbr_hdr.sector = bp->bio_offset / VTBLK_BSIZE;
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break;
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default:
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panic("%s: bio with unhandled cmd: %d", __func__, bp->bio_cmd);
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@ -935,6 +957,20 @@ vtblk_request_execute(struct vtblk_softc *sc, struct vtblk_request *req)
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/* BIO_READ means the host writes into our buffer. */
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if (bp->bio_cmd == BIO_READ)
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writable = sg->sg_nseg - 1;
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} else if (bp->bio_cmd == BIO_DELETE) {
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struct virtio_blk_discard_write_zeroes *discard;
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discard = malloc(sizeof(*discard), M_DEVBUF, M_NOWAIT | M_ZERO);
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if (discard == NULL)
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return (ENOMEM);
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discard->sector = bp->bio_offset / VTBLK_BSIZE;
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discard->num_sectors = bp->bio_bcount / VTBLK_BSIZE;
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bp->bio_driver1 = discard;
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error = sglist_append(sg, discard, sizeof(*discard));
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if (error || sg->sg_nseg == sg->sg_maxseg) {
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panic("%s: bio %p data buffer too big %d",
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__func__, bp, error);
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}
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}
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writable++;
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@ -1095,6 +1131,11 @@ vtblk_bio_done(struct vtblk_softc *sc, struct bio *bp, int error)
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bp->bio_flags |= BIO_ERROR;
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}
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if (bp->bio_driver1 != NULL) {
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free(bp->bio_driver1, M_DEVBUF);
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bp->bio_driver1 = NULL;
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}
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biodone(bp);
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}
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@ -1124,7 +1165,12 @@ vtblk_read_config(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg)
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VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_GEOMETRY, geometry, blkcfg);
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VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_BLK_SIZE, blk_size, blkcfg);
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VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_TOPOLOGY, topology, blkcfg);
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VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_CONFIG_WCE, writeback, blkcfg);
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VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_CONFIG_WCE, wce, blkcfg);
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VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_DISCARD, max_discard_sectors,
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blkcfg);
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VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_DISCARD, max_discard_seg, blkcfg);
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VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_DISCARD, discard_sector_alignment,
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blkcfg);
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}
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#undef VTBLK_GET_CONFIG
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@ -1282,7 +1328,7 @@ vtblk_dump_write(struct vtblk_softc *sc, void *virtual, off_t offset,
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req->vbr_ack = -1;
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req->vbr_hdr.type = VIRTIO_BLK_T_OUT;
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req->vbr_hdr.ioprio = 1;
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req->vbr_hdr.sector = offset / 512;
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req->vbr_hdr.sector = offset / VTBLK_BSIZE;
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req->vbr_bp = &buf;
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g_reset_bio(&buf);
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@ -1331,7 +1377,7 @@ vtblk_set_write_cache(struct vtblk_softc *sc, int wc)
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/* Set either writeback (1) or writethrough (0) mode. */
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virtio_write_dev_config_1(sc->vtblk_dev,
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offsetof(struct virtio_blk_config, writeback), wc);
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offsetof(struct virtio_blk_config, wce), wc);
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}
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static int
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@ -1346,7 +1392,7 @@ vtblk_write_cache_enabled(struct vtblk_softc *sc,
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if (wc >= 0 && wc < VTBLK_CACHE_MAX)
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vtblk_set_write_cache(sc, wc);
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else
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wc = blkcfg->writeback;
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wc = blkcfg->wce;
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} else
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wc = virtio_with_feature(sc->vtblk_dev, VIRTIO_BLK_F_WCE);
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@ -33,19 +33,26 @@
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#ifndef _VIRTIO_BLK_H
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#define _VIRTIO_BLK_H
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/* Feature bits */
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#define VIRTIO_BLK_F_BARRIER 0x0001 /* Does host support barriers? */
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#define VIRTIO_BLK_F_SIZE_MAX 0x0002 /* Indicates maximum segment size */
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#define VIRTIO_BLK_F_SEG_MAX 0x0004 /* Indicates maximum # of segments */
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#define VIRTIO_BLK_F_GEOMETRY 0x0010 /* Legacy geometry available */
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#define VIRTIO_BLK_F_RO 0x0020 /* Disk is read-only */
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#define VIRTIO_BLK_F_BLK_SIZE 0x0040 /* Block size of disk is available*/
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#define VIRTIO_BLK_F_SCSI 0x0080 /* Supports scsi command passthru */
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#define VIRTIO_BLK_F_WCE 0x0200 /* Writeback mode enabled after reset */
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#define VIRTIO_BLK_F_TOPOLOGY 0x0400 /* Topology information is available */
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#define VIRTIO_BLK_F_CONFIG_WCE 0x0800 /* Writeback mode available in config */
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#define VTBLK_BSIZE 512
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#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
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/* Feature bits */
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#define VIRTIO_BLK_F_BARRIER 0x0001 /* Does host support barriers? */
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#define VIRTIO_BLK_F_SIZE_MAX 0x0002 /* Indicates maximum segment size */
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#define VIRTIO_BLK_F_SEG_MAX 0x0004 /* Indicates maximum # of segments */
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#define VIRTIO_BLK_F_GEOMETRY 0x0010 /* Legacy geometry available */
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#define VIRTIO_BLK_F_RO 0x0020 /* Disk is read-only */
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#define VIRTIO_BLK_F_BLK_SIZE 0x0040 /* Block size of disk is available*/
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#define VIRTIO_BLK_F_SCSI 0x0080 /* Supports scsi command passthru */
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#define VIRTIO_BLK_F_FLUSH 0x0200 /* Flush command supported */
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#define VIRTIO_BLK_F_WCE 0x0200 /* Legacy alias for FLUSH */
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#define VIRTIO_BLK_F_TOPOLOGY 0x0400 /* Topology information is available */
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#define VIRTIO_BLK_F_CONFIG_WCE 0x0800 /* Writeback mode available in config */
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#define VIRTIO_BLK_F_MQ 0x1000 /* Support more than one vq */
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#define VIRTIO_BLK_F_DISCARD 0x2000 /* Trim blocks */
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#define VIRTIO_BLK_F_WRITE_ZEROES 0x4000 /* Write zeros */
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#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
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struct virtio_blk_config {
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/* The capacity (in 512-byte sectors). */
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@ -66,15 +73,29 @@ struct virtio_blk_config {
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/* Topology of the device (if VIRTIO_BLK_F_TOPOLOGY) */
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struct virtio_blk_topology {
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/* Exponent for physical block per logical block. */
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uint8_t physical_block_exp;
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/* Alignment offset in logical blocks. */
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uint8_t alignment_offset;
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/* Minimum I/O size without performance penalty in logical
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* blocks. */
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uint16_t min_io_size;
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/* Optimal sustained I/O size in logical blocks. */
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uint32_t opt_io_size;
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} topology;
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/* Writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
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uint8_t writeback;
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uint8_t wce;
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uint8_t unused;
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/* Number of vqs, only available when VIRTIO_BLK_F_MQ is set */
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uint16_t num_queues;
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uint32_t max_discard_sectors;
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uint32_t max_discard_seg;
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uint32_t discard_sector_alignment;
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uint32_t max_write_zeroes_sectors;
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uint32_t max_write_zeroes_seg;
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uint8_t write_zeroes_may_unmap;
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uint8_t unused1[3];
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} __packed;
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/*
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@ -89,23 +110,34 @@ struct virtio_blk_config {
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*/
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/* These two define direction. */
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#define VIRTIO_BLK_T_IN 0
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#define VIRTIO_BLK_T_OUT 1
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#define VIRTIO_BLK_T_IN 0
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#define VIRTIO_BLK_T_OUT 1
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/* This bit says it's a scsi command, not an actual read or write. */
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#define VIRTIO_BLK_T_SCSI_CMD 2
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#define VIRTIO_BLK_T_SCSI_CMD 2
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#define VIRTIO_BLK_T_SCSI_CMD_OUT 3
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/* Cache flush command */
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#define VIRTIO_BLK_T_FLUSH 4
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#define VIRTIO_BLK_T_FLUSH 4
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#define VIRTIO_BLK_T_FLUSH_OUT 5
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/* Get device ID command */
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#define VIRTIO_BLK_T_GET_ID 8
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#define VIRTIO_BLK_T_GET_ID 8
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/* Discard command */
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#define VIRTIO_BLK_T_DISCARD 11
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/* Write zeros command */
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#define VIRTIO_BLK_T_WRITE_ZEROES 13
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/* Barrier before this op. */
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#define VIRTIO_BLK_T_BARRIER 0x80000000
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#define VIRTIO_BLK_T_BARRIER 0x80000000
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/* ID string length */
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#define VIRTIO_BLK_ID_BYTES 20
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#define VIRTIO_BLK_ID_BYTES 20
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/* Unmap this range (only valid for write zeroes command) */
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#define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001
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/* This is the first element of the read scatter-gather list. */
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struct virtio_blk_outhdr {
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@ -117,6 +149,15 @@ struct virtio_blk_outhdr {
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uint64_t sector;
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};
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struct virtio_blk_discard_write_zeroes {
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uint64_t sector;
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uint32_t num_sectors;
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struct {
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uint32_t unmap:1;
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uint32_t reserved:31;
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} flags;
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};
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struct virtio_scsi_inhdr {
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uint32_t errors;
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uint32_t data_len;
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