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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:
Konrad Rzeszutek Wilk 2011-10-12 16:23:30 -04:00
parent 97e36834f5
commit 5ea4298669
5 changed files with 77 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/block/xen-blkback/blkback.c
View File

@ -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;
/*

7
drivers/block/xen-blkback/common.h
View File

@ -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;

12
drivers/block/xen-blkback/xenbus.c
View File

@ -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);

41
drivers/block/xen-blkfront.c
View File

@ -98,7 +98,8 @@ struct blkfront_info
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 @@ static int blkif_queue_request(struct request *req)
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 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
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_free(struct blkfront_info *info, int suspend)
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 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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 @@ static int blkif_recover(struct blkfront_info *info)
req->u.rw.id = get_id_from_freelist(info);
memcpy(&info->shadow[req->u.rw.id], &copy[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 @@ static void blkfront_setup_discard(struct blkfront_info *info)
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 @@ static void blkfront_setup_discard(struct blkfront_info *info)
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;

18
include/xen/interface/io/blkif.h
View File

@ -84,6 +84,21 @@ typedef uint64_t blkif_sector_t;
* e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
* http://www.seagate.com/staticfiles/support/disc/manuals/
* Interface%20manuals/100293068c.pdf
* The backend can optionally provide three extra XenBus attributes to
* further optimize the discard functionality:
* 'discard-aligment' - Devices that support discard functionality may
* internally allocate space in units that are bigger than the exported
* logical block size. The discard-alignment parameter indicates how many bytes
* the beginning of the partition is offset from the internal allocation unit's
* natural alignment.
* 'discard-granularity' - Devices that support discard functionality may
* internally allocate space using units that are bigger than the logical block
* size. The discard-granularity parameter indicates the size of the internal
* allocation unit in bytes if reported by the device. Otherwise the
* discard-granularity will be set to match the device's physical block size.
* 'discard-secure' - All copies of the discarded sectors (potentially created
* by garbage collection) must also be erased. To use this feature, the flag
* BLKIF_DISCARD_SECURE must be set in the blkif_request_trim.
*/
#define BLKIF_OP_DISCARD 5
@ -111,7 +126,8 @@ struct blkif_request_rw {
} __attribute__((__packed__));
struct blkif_request_discard {
uint8_t nr_segments; /* number of segments */
uint8_t flag; /* BLKIF_DISCARD_SECURE or zero. */
#define BLKIF_DISCARD_SECURE (1<<0) /* ignored if discard-secure=0 */
blkif_vdev_t _pad1; /* only for read/write requests */
#ifdef CONFIG_X86_64
uint32_t _pad2; /* offsetof(blkif_req..,u.discard.id)==8*/