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>
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 2c2c4be..351ddef 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -98,7 +98,8 @@
unsigned long shadow_free;
unsigned int feature_flush;
unsigned int flush_op;
- unsigned int feature_discard;
+ unsigned int feature_discard:1;
+ unsigned int feature_secdiscard:1;
unsigned int discard_granularity;
unsigned int discard_alignment;
int is_ready;
@@ -305,11 +306,14 @@
ring_req->operation = info->flush_op;
}
- if (unlikely(req->cmd_flags & REQ_DISCARD)) {
+ if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {
/* id, sector_number and handle are set above. */
ring_req->operation = BLKIF_OP_DISCARD;
- ring_req->u.discard.nr_segments = 0;
ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
+ if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
+ ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
+ else
+ ring_req->u.discard.flag = 0;
} else {
ring_req->u.rw.nr_segments = blk_rq_map_sg(req->q, req,
info->sg);
@@ -426,6 +430,8 @@
blk_queue_max_discard_sectors(rq, get_capacity(gd));
rq->limits.discard_granularity = info->discard_granularity;
rq->limits.discard_alignment = info->discard_alignment;
+ if (info->feature_secdiscard)
+ queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
}
/* Hard sector size and max sectors impersonate the equiv. hardware. */
@@ -707,6 +713,8 @@
static void blkif_completion(struct blk_shadow *s)
{
int i;
+ /* Do not let BLKIF_OP_DISCARD as nr_segment is in the same place
+ * flag. */
for (i = 0; i < s->req.u.rw.nr_segments; i++)
gnttab_end_foreign_access(s->req.u.rw.seg[i].gref, 0, 0UL);
}
@@ -738,7 +746,8 @@
id = bret->id;
req = info->shadow[id].request;
- blkif_completion(&info->shadow[id]);
+ if (bret->operation != BLKIF_OP_DISCARD)
+ blkif_completion(&info->shadow[id]);
add_id_to_freelist(info, id);
@@ -751,7 +760,9 @@
info->gd->disk_name);
error = -EOPNOTSUPP;
info->feature_discard = 0;
+ info->feature_secdiscard = 0;
queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
+ queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
}
__blk_end_request_all(req, error);
break;
@@ -1039,13 +1050,15 @@
req->u.rw.id = get_id_from_freelist(info);
memcpy(&info->shadow[req->u.rw.id], ©[i], sizeof(copy[i]));
+ if (req->operation != BLKIF_OP_DISCARD) {
/* Rewrite any grant references invalidated by susp/resume. */
- for (j = 0; j < req->u.rw.nr_segments; j++)
- gnttab_grant_foreign_access_ref(
- req->u.rw.seg[j].gref,
- info->xbdev->otherend_id,
- pfn_to_mfn(info->shadow[req->u.rw.id].frame[j]),
- rq_data_dir(info->shadow[req->u.rw.id].request));
+ for (j = 0; j < req->u.rw.nr_segments; j++)
+ gnttab_grant_foreign_access_ref(
+ req->u.rw.seg[j].gref,
+ info->xbdev->otherend_id,
+ pfn_to_mfn(info->shadow[req->u.rw.id].frame[j]),
+ rq_data_dir(info->shadow[req->u.rw.id].request));
+ }
info->shadow[req->u.rw.id].req = *req;
info->ring.req_prod_pvt++;
@@ -1137,11 +1150,13 @@
char *type;
unsigned int discard_granularity;
unsigned int discard_alignment;
+ unsigned int discard_secure;
type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
if (IS_ERR(type))
return;
+ info->feature_secdiscard = 0;
if (strncmp(type, "phy", 3) == 0) {
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"discard-granularity", "%u", &discard_granularity,
@@ -1152,6 +1167,12 @@
info->discard_granularity = discard_granularity;
info->discard_alignment = discard_alignment;
}
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-secure", "%d", &discard_secure,
+ NULL);
+ if (!err)
+ info->feature_secdiscard = discard_secure;
+
} else if (strncmp(type, "file", 4) == 0)
info->feature_discard = 1;