diff options
| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-10-12 16:23:30 -0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-11-18 13:28:01 -0500 |
| commit | 5ea42986694a96542644f9cae8b122d3a00c508f (patch) | |
| tree | dd74685d8cd41e39ad14e708cb6e00e0ed016fb1 /include | |
| parent | 97e36834f5a106459ab1b290e663a4eb6264639e (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 'include')
| -rw-r--r-- | include/xen/interface/io/blkif.h | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h index f88e28b6a27..ee338bfde18 100644 --- a/include/xen/interface/io/blkif.h +++ b/include/xen/interface/io/blkif.h @@ -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*/ |