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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
xen/blk[front|back]: Enhance discard support with secure erasing support.
Part of the blkdev_issue_discard(xx) operation is that it can also issue a secure discard operation that will permanantly remove the sectors in question. We advertise that we can support that via the 'discard-secure' attribute and on the request, if the 'secure' bit is set, we will attempt to pass in REQ_DISCARD | REQ_SECURE. CC: Li Dongyang <lidongyang@novell.com> [v1: Used 'flag' instead of 'secure:1' bit] [v2: Use 'reserved' uint8_t instead of adding a new value] [v3: Check for nseg when mapping instead of operation] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
parent
97e36834f5
commit
5ea4298669
5 changed files with 77 additions and 19 deletions
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@ -422,13 +422,16 @@ static void xen_blk_discard(struct xen_blkif *blkif, struct blkif_request *req)
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int status = BLKIF_RSP_OKAY;
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struct block_device *bdev = blkif->vbd.bdev;
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if (blkif->blk_backend_type == BLKIF_BACKEND_PHY)
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if (blkif->blk_backend_type == BLKIF_BACKEND_PHY) {
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unsigned long secure = (blkif->vbd.discard_secure &&
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(req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
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BLKDEV_DISCARD_SECURE : 0;
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/* just forward the discard request */
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err = blkdev_issue_discard(bdev,
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req->u.discard.sector_number,
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req->u.discard.nr_sectors,
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GFP_KERNEL, 0);
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else if (blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
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GFP_KERNEL, secure);
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} else if (blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
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/* punch a hole in the backing file */
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struct loop_device *lo = bdev->bd_disk->private_data;
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struct file *file = lo->lo_backing_file;
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@ -643,8 +646,11 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
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break;
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}
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/* Check that the number of segments is sane. */
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nseg = req->u.rw.nr_segments;
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if (unlikely(operation == REQ_DISCARD))
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nseg = 0;
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else
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/* Check that the number of segments is sane. */
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nseg = req->u.rw.nr_segments;
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if (unlikely(nseg == 0 && operation != WRITE_FLUSH &&
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operation != REQ_DISCARD) ||
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@ -708,7 +714,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
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* the hypercall to unmap the grants - that is all done in
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* xen_blkbk_unmap.
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*/
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if (operation != REQ_DISCARD && xen_blkbk_map(req, pending_req, seg))
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if (nseg && xen_blkbk_map(req, pending_req, seg))
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goto fail_flush;
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/*
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@ -69,7 +69,7 @@ struct blkif_x86_32_request_rw {
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} __attribute__((__packed__));
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struct blkif_x86_32_request_discard {
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uint8_t nr_segments; /* number of segments */
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uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
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blkif_vdev_t _pad1; /* was "handle" for read/write requests */
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uint64_t id; /* private guest value, echoed in resp */
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blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
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@ -104,7 +104,7 @@ struct blkif_x86_64_request_rw {
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} __attribute__((__packed__));
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struct blkif_x86_64_request_discard {
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uint8_t nr_segments; /* number of segments */
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uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
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blkif_vdev_t _pad1; /* was "handle" for read/write requests */
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uint32_t _pad2; /* offsetof(blkif_..,u.discard.id)==8 */
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uint64_t id;
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@ -164,6 +164,7 @@ struct xen_vbd {
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/* Cached size parameter. */
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sector_t size;
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bool flush_support;
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bool discard_secure;
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};
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struct backend_info;
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@ -261,6 +262,7 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
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dst->u.rw.seg[i] = src->u.rw.seg[i];
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break;
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case BLKIF_OP_DISCARD:
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dst->u.discard.flag = src->u.discard.flag;
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dst->u.discard.sector_number = src->u.discard.sector_number;
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dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
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break;
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@ -290,6 +292,7 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst,
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dst->u.rw.seg[i] = src->u.rw.seg[i];
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break;
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case BLKIF_OP_DISCARD:
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dst->u.discard.flag = src->u.discard.flag;
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dst->u.discard.sector_number = src->u.discard.sector_number;
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dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
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break;
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@ -338,6 +338,9 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
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if (q && q->flush_flags)
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vbd->flush_support = true;
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if (q && blk_queue_secdiscard(q))
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vbd->discard_secure = true;
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DPRINTK("Successful creation of handle=%04x (dom=%u)\n",
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handle, blkif->domid);
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return 0;
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@ -420,6 +423,15 @@ int xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
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state = 1;
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blkif->blk_backend_type = BLKIF_BACKEND_PHY;
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}
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/* Optional. */
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err = xenbus_printf(xbt, dev->nodename,
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"discard-secure", "%d",
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blkif->vbd.discard_secure);
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if (err) {
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xenbus_dev_fatal(dev, err,
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"writting discard-secure");
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goto kfree;
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}
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}
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} else {
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err = PTR_ERR(type);
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@ -98,7 +98,8 @@ struct blkfront_info
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unsigned long shadow_free;
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unsigned int feature_flush;
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unsigned int flush_op;
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unsigned int feature_discard;
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unsigned int feature_discard:1;
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unsigned int feature_secdiscard:1;
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unsigned int discard_granularity;
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unsigned int discard_alignment;
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int is_ready;
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@ -305,11 +306,14 @@ static int blkif_queue_request(struct request *req)
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ring_req->operation = info->flush_op;
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}
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if (unlikely(req->cmd_flags & REQ_DISCARD)) {
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if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {
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/* id, sector_number and handle are set above. */
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ring_req->operation = BLKIF_OP_DISCARD;
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ring_req->u.discard.nr_segments = 0;
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ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
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if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
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ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
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else
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ring_req->u.discard.flag = 0;
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} else {
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ring_req->u.rw.nr_segments = blk_rq_map_sg(req->q, req,
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info->sg);
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@ -426,6 +430,8 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
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blk_queue_max_discard_sectors(rq, get_capacity(gd));
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rq->limits.discard_granularity = info->discard_granularity;
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rq->limits.discard_alignment = info->discard_alignment;
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if (info->feature_secdiscard)
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queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
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}
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/* Hard sector size and max sectors impersonate the equiv. hardware. */
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@ -707,6 +713,8 @@ static void blkif_free(struct blkfront_info *info, int suspend)
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static void blkif_completion(struct blk_shadow *s)
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{
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int i;
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/* Do not let BLKIF_OP_DISCARD as nr_segment is in the same place
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* flag. */
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for (i = 0; i < s->req.u.rw.nr_segments; i++)
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gnttab_end_foreign_access(s->req.u.rw.seg[i].gref, 0, 0UL);
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}
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@ -738,7 +746,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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id = bret->id;
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req = info->shadow[id].request;
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blkif_completion(&info->shadow[id]);
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if (bret->operation != BLKIF_OP_DISCARD)
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blkif_completion(&info->shadow[id]);
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add_id_to_freelist(info, id);
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@ -751,7 +760,9 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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info->gd->disk_name);
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error = -EOPNOTSUPP;
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info->feature_discard = 0;
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info->feature_secdiscard = 0;
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queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
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queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
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}
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__blk_end_request_all(req, error);
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break;
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@ -1039,13 +1050,15 @@ static int blkif_recover(struct blkfront_info *info)
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req->u.rw.id = get_id_from_freelist(info);
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memcpy(&info->shadow[req->u.rw.id], ©[i], sizeof(copy[i]));
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if (req->operation != BLKIF_OP_DISCARD) {
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/* Rewrite any grant references invalidated by susp/resume. */
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for (j = 0; j < req->u.rw.nr_segments; j++)
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gnttab_grant_foreign_access_ref(
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req->u.rw.seg[j].gref,
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info->xbdev->otherend_id,
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pfn_to_mfn(info->shadow[req->u.rw.id].frame[j]),
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rq_data_dir(info->shadow[req->u.rw.id].request));
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for (j = 0; j < req->u.rw.nr_segments; j++)
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gnttab_grant_foreign_access_ref(
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req->u.rw.seg[j].gref,
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info->xbdev->otherend_id,
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pfn_to_mfn(info->shadow[req->u.rw.id].frame[j]),
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rq_data_dir(info->shadow[req->u.rw.id].request));
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}
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info->shadow[req->u.rw.id].req = *req;
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info->ring.req_prod_pvt++;
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char *type;
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unsigned int discard_granularity;
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unsigned int discard_alignment;
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unsigned int discard_secure;
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type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
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if (IS_ERR(type))
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return;
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info->feature_secdiscard = 0;
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if (strncmp(type, "phy", 3) == 0) {
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err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
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"discard-granularity", "%u", &discard_granularity,
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info->discard_granularity = discard_granularity;
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info->discard_alignment = discard_alignment;
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}
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err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
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"discard-secure", "%d", &discard_secure,
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NULL);
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if (!err)
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info->feature_secdiscard = discard_secure;
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} else if (strncmp(type, "file", 4) == 0)
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info->feature_discard = 1;
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@ -84,6 +84,21 @@ typedef uint64_t blkif_sector_t;
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* e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
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* http://www.seagate.com/staticfiles/support/disc/manuals/
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* Interface%20manuals/100293068c.pdf
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* The backend can optionally provide three extra XenBus attributes to
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* further optimize the discard functionality:
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* 'discard-aligment' - Devices that support discard functionality may
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* internally allocate space in units that are bigger than the exported
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* logical block size. The discard-alignment parameter indicates how many bytes
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* the beginning of the partition is offset from the internal allocation unit's
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* natural alignment.
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* 'discard-granularity' - Devices that support discard functionality may
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* internally allocate space using units that are bigger than the logical block
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* size. The discard-granularity parameter indicates the size of the internal
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* allocation unit in bytes if reported by the device. Otherwise the
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* discard-granularity will be set to match the device's physical block size.
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* 'discard-secure' - All copies of the discarded sectors (potentially created
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* by garbage collection) must also be erased. To use this feature, the flag
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* BLKIF_DISCARD_SECURE must be set in the blkif_request_trim.
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*/
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#define BLKIF_OP_DISCARD 5
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@ -111,7 +126,8 @@ struct blkif_request_rw {
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} __attribute__((__packed__));
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struct blkif_request_discard {
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uint8_t nr_segments; /* number of segments */
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uint8_t flag; /* BLKIF_DISCARD_SECURE or zero. */
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#define BLKIF_DISCARD_SECURE (1<<0) /* ignored if discard-secure=0 */
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blkif_vdev_t _pad1; /* only for read/write requests */
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#ifdef CONFIG_X86_64
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uint32_t _pad2; /* offsetof(blkif_req..,u.discard.id)==8*/
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