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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-10-12 16:23:30 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-11-18 13:28:01 -0500
commit5ea42986694a96542644f9cae8b122d3a00c508f (patch)
treedd74685d8cd41e39ad14e708cb6e00e0ed016fb1 /drivers/block/xen-blkback
parent97e36834f5a106459ab1b290e663a4eb6264639e (diff)
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>
Diffstat (limited to 'drivers/block/xen-blkback')
-rw-r--r--drivers/block/xen-blkback/blkback.c18
-rw-r--r--drivers/block/xen-blkback/common.h7
-rw-r--r--drivers/block/xen-blkback/xenbus.c12
3 files changed, 29 insertions, 8 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index d7104abc8b7..9d2261b02f2 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -422,13 +422,16 @@ static void xen_blk_discard(struct xen_blkif *blkif, struct blkif_request *req)
int status = BLKIF_RSP_OKAY;
struct block_device *bdev = blkif->vbd.bdev;
- if (blkif->blk_backend_type == BLKIF_BACKEND_PHY)
+ if (blkif->blk_backend_type == BLKIF_BACKEND_PHY) {
+ unsigned long secure = (blkif->vbd.discard_secure &&
+ (req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
+ BLKDEV_DISCARD_SECURE : 0;
/* just forward the discard request */
err = blkdev_issue_discard(bdev,
req->u.discard.sector_number,
req->u.discard.nr_sectors,
- GFP_KERNEL, 0);
- else if (blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
+ GFP_KERNEL, secure);
+ } else if (blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
/* punch a hole in the backing file */
struct loop_device *lo = bdev->bd_disk->private_data;
struct file *file = lo->lo_backing_file;
@@ -643,8 +646,11 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
break;
}
- /* Check that the number of segments is sane. */
- nseg = req->u.rw.nr_segments;
+ if (unlikely(operation == REQ_DISCARD))
+ nseg = 0;
+ else
+ /* Check that the number of segments is sane. */
+ nseg = req->u.rw.nr_segments;
if (unlikely(nseg == 0 && operation != WRITE_FLUSH &&
operation != REQ_DISCARD) ||
@@ -708,7 +714,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
* the hypercall to unmap the grants - that is all done in
* xen_blkbk_unmap.
*/
- if (operation != REQ_DISCARD && xen_blkbk_map(req, pending_req, seg))
+ if (nseg && xen_blkbk_map(req, pending_req, seg))
goto fail_flush;
/*
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index dbfe7b3b073..d0ee7edc9be 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -69,7 +69,7 @@ struct blkif_x86_32_request_rw {
} __attribute__((__packed__));
struct blkif_x86_32_request_discard {
- uint8_t nr_segments; /* number of segments */
+ uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
blkif_vdev_t _pad1; /* was "handle" for read/write requests */
uint64_t id; /* private guest value, echoed in resp */
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
@@ -104,7 +104,7 @@ struct blkif_x86_64_request_rw {
} __attribute__((__packed__));
struct blkif_x86_64_request_discard {
- uint8_t nr_segments; /* number of segments */
+ uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
blkif_vdev_t _pad1; /* was "handle" for read/write requests */
uint32_t _pad2; /* offsetof(blkif_..,u.discard.id)==8 */
uint64_t id;
@@ -164,6 +164,7 @@ struct xen_vbd {
/* Cached size parameter. */
sector_t size;
bool flush_support;
+ bool discard_secure;
};
struct backend_info;
@@ -261,6 +262,7 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
dst->u.rw.seg[i] = src->u.rw.seg[i];
break;
case BLKIF_OP_DISCARD:
+ dst->u.discard.flag = src->u.discard.flag;
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
@@ -290,6 +292,7 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst,
dst->u.rw.seg[i] = src->u.rw.seg[i];
break;
case BLKIF_OP_DISCARD:
+ dst->u.discard.flag = src->u.discard.flag;
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index f759ad4584c..187fd2c1a15 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -338,6 +338,9 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
if (q && q->flush_flags)
vbd->flush_support = true;
+ if (q && blk_queue_secdiscard(q))
+ vbd->discard_secure = true;
+
DPRINTK("Successful creation of handle=%04x (dom=%u)\n",
handle, blkif->domid);
return 0;
@@ -420,6 +423,15 @@ int xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
state = 1;
blkif->blk_backend_type = BLKIF_BACKEND_PHY;
}
+ /* Optional. */
+ err = xenbus_printf(xbt, dev->nodename,
+ "discard-secure", "%d",
+ blkif->vbd.discard_secure);
+ if (err) {
+ xenbus_dev_fatal(dev, err,
+ "writting discard-secure");
+ goto kfree;
+ }
}
} else {
err = PTR_ERR(type);