Konrad Rzeszutek Wilk
2011-Oct-10 17:50 UTC
[Xen-devel] [PATCH 0 of 1] Patch to alter BLKIF_OP_TRIM to BLKIF_OP_DISCARD (v2).
I posted the v1 version of these patches some time ago and they were looked by Paul and Li and both of them were OK with it. I was wondering if either one of the maintainers (tools?) would be willing to commit this patch in? Thanks! _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Konrad Rzeszutek Wilk
2011-Oct-10 17:50 UTC
[Xen-devel] [PATCH 1 of 1] interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD
# HG changeset patch
# User Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
# Date 1318268906 14400
# Node ID d17ab29f2f9ad29a7b8af02d6f17de7f112a9723
# Parent 72f339bc600d7a9629d3f9eb8a279fbf8be25b12
interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD
The name 'trim' is specific to the ATA discard implementation.
The name 'scsi unmap' is specific to the SCSI discard implementation.
We should really use a generic name - and the name 'discard'
looks to be the most generic of them all.
CC: lidongyang@novell.com
CC: owen.smith@citrix.com
CC: Pasi Kärkkäinen <pasik@iki.fi>
CC: JBeulich@novell.com
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff -r 72f339bc600d -r d17ab29f2f9a xen/include/public/io/blkif.h
--- a/xen/include/public/io/blkif.h Mon Oct 10 11:21:51 2011 +0100
+++ b/xen/include/public/io/blkif.h Mon Oct 10 13:48:26 2011 -0400
@@ -82,26 +82,37 @@
*/
#define BLKIF_OP_RESERVED_1 4
/*
- * Recognised only if "feature-trim" is present in backend xenbus
info.
- * The "feature-trim" node contains a boolean indicating whether trim
- * requests are likely to succeed or fail. Either way, a trim request
+ * Recognised only if "feature-discard" is present in backend xenbus
info.
+ * The "feature-discard" node contains a boolean indicating whether
trim
+ * (ATA) or unmap (SCSI) - conviently called discard requests are likely
+ * to succeed or fail. Either way, a discard request
* may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
* the underlying block-device hardware. The boolean simply indicates whether
- * or not it is worthwhile for the frontend to attempt trim requests.
- * If a backend does not recognise BLKIF_OP_TRIM, it should *not*
- * create the "feature-trim" node!
- *
- * Trim operation is a request for the underlying block device to mark
- * extents to be erased. Trim operations are passed with sector_number as the
- * sector index to begin trim operations at and nr_sectors as the number of
- * sectors to be trimmed. The specified sectors should be trimmed if the
- * underlying block device supports trim operations, or a BLKIF_RSP_EOPNOTSUPP
- * should be returned. More information about trim operations at:
+ * or not it is worthwhile for the frontend to attempt discard requests.
+ * If a backend does not recognise BLKIF_OP_DISCARD, it should *not*
+ * create the "feature-discard" node!
+ *
+ * Discard operation is a request for the underlying block device to mark
+ * extents to be erased. However, discard does not guarantee that the blocks
+ * will be erased from the device - it is just a hint to the device
+ * controller that these blocks are no longer in use. What the device
+ * controller does with that information is left to the controller.
+ * Discard operations are passed with sector_number as the
+ * sector index to begin discard operations at and nr_sectors as the number of
+ * sectors to be discarded. The specified sectors should be discarded if the
+ * underlying block device supports trim (ATA) or unmap (SCSI) operations,
+ * or a BLKIF_RSP_EOPNOTSUPP should be returned.
+ * More information about trim/unmap operations at:
* http://t13.org/Documents/UploadedDocuments/docs2008/
* e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
+ * http://www.seagate.com/staticfiles/support/disc/manuals/
+ * Interface%20manuals/100293068c.pdf
+ * We also provide three extra XenBus options to the discard operation:
+ * 'discard-granularity' - Max amount of sectors that can be discarded.
+ * 'discard-alignment' - 4K, 128K, etc aligment on sectors to erased.
+ * 'discard-secure' - whether the discard can also securely erase data.
*/
-#define BLKIF_OP_TRIM 5
-
+#define BLKIF_OP_DISCARD 5
/*
* Maximum scatter/gather segments per request.
* This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE.
@@ -134,18 +145,21 @@ struct blkif_request {
typedef struct blkif_request blkif_request_t;
/*
- * Cast to this structure when blkif_request.operation == BLKIF_OP_TRIM
- * sizeof(struct blkif_request_trim) <= sizeof(struct blkif_request)
+ * Cast to this structure when blkif_request.operation == BLKIF_OP_DISCARD
+ * sizeof(struct blkif_request_discard) <= sizeof(struct blkif_request)
*/
-struct blkif_request_trim {
- uint8_t operation; /* BLKIF_OP_TRIM */
+struct blkif_request_discard {
+ uint8_t operation; /* BLKIF_OP_DISCARD */
uint8_t reserved; /* */
blkif_vdev_t handle; /* same as for read/write requests */
uint64_t id; /* private guest value, echoed in resp */
blkif_sector_t sector_number;/* start sector idx on disk */
uint64_t nr_sectors; /* number of contiguous sectors to trim */
+ /* ignored if 'discard-secure=0'
*/
+#define BLKIF_OP_DISCARD_FLAG_SECURE (1<<1)
+ uint32_t flag;
};
-typedef struct blkif_request_trim blkif_request_trim_t;
+typedef struct blkif_request_discard blkif_request_discard_t;
struct blkif_response {
uint64_t id; /* copied from request */
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel
Konrad Rzeszutek Wilk
2011-Oct-10 19:58 UTC
Re: [Xen-devel] [PATCH 1 of 1] interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD
On Mon, Oct 10, 2011 at 01:50:11PM -0400, Konrad Rzeszutek Wilk wrote:> # HG changeset patch > # User Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > # Date 1318268906 14400 > # Node ID d17ab29f2f9ad29a7b8af02d6f17de7f112a9723 > # Parent 72f339bc600d7a9629d3f9eb8a279fbf8be25b12 > interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD >Per Ian''s suggestion: # HG changeset patch # Parent 72f339bc600d7a9629d3f9eb8a279fbf8be25b12 interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD The name ''trim'' is specific to the ATA discard implementation. The name ''scsi unmap'' is specific to the SCSI discard implementation. We should really use a generic name - and the name ''discard'' looks to be the most generic of them all. CC: lidongyang@novell.com CC: owen.smith@citrix.com CC: Pasi Kärkkäinen <pasik@iki.fi> CC: JBeulich@novell.com Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> diff -r 72f339bc600d xen/include/public/io/blkif.h --- a/xen/include/public/io/blkif.h Mon Oct 10 11:21:51 2011 +0100 +++ b/xen/include/public/io/blkif.h Mon Oct 10 15:54:51 2011 -0400 @@ -82,26 +82,47 @@ */ #define BLKIF_OP_RESERVED_1 4 /* - * Recognised only if "feature-trim" is present in backend xenbus info. - * The "feature-trim" node contains a boolean indicating whether trim - * requests are likely to succeed or fail. Either way, a trim request + * Recognised only if "feature-discard" is present in backend xenbus info. + * The "feature-discard" node contains a boolean indicating whether trim + * (ATA) or unmap (SCSI) - conviently called discard requests are likely + * to succeed or fail. Either way, a discard request * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by * the underlying block-device hardware. The boolean simply indicates whether - * or not it is worthwhile for the frontend to attempt trim requests. - * If a backend does not recognise BLKIF_OP_TRIM, it should *not* - * create the "feature-trim" node! - * - * Trim operation is a request for the underlying block device to mark - * extents to be erased. Trim operations are passed with sector_number as the - * sector index to begin trim operations at and nr_sectors as the number of - * sectors to be trimmed. The specified sectors should be trimmed if the - * underlying block device supports trim operations, or a BLKIF_RSP_EOPNOTSUPP - * should be returned. More information about trim operations at: + * or not it is worthwhile for the frontend to attempt discard requests. + * If a backend does not recognise BLKIF_OP_DISCARD, it should *not* + * create the "feature-discard" node! + * + * Discard operation is a request for the underlying block device to mark + * extents to be erased. However, discard does not guarantee that the blocks + * will be erased from the device - it is just a hint to the device + * controller that these blocks are no longer in use. What the device + * controller does with that information is left to the controller. + * Discard operations are passed with sector_number as the + * sector index to begin discard operations at and nr_sectors as the number of + * sectors to be discarded. The specified sectors should be discarded if the + * underlying block device supports trim (ATA) or unmap (SCSI) operations, + * or a BLKIF_RSP_EOPNOTSUPP should be returned. + * More information about trim/unmap operations at: * http://t13.org/Documents/UploadedDocuments/docs2008/ * 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. */ -#define BLKIF_OP_TRIM 5 - +#define BLKIF_OP_DISCARD 5 /* * Maximum scatter/gather segments per request. * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE. @@ -134,18 +155,22 @@ struct blkif_request { typedef struct blkif_request blkif_request_t; /* - * Cast to this structure when blkif_request.operation == BLKIF_OP_TRIM - * sizeof(struct blkif_request_trim) <= sizeof(struct blkif_request) + * Cast to this structure when blkif_request.operation == BLKIF_OP_DISCARD + * sizeof(struct blkif_request_discard) <= sizeof(struct blkif_request) */ -struct blkif_request_trim { - uint8_t operation; /* BLKIF_OP_TRIM */ +struct blkif_request_discard { + uint8_t operation; /* BLKIF_OP_DISCARD */ uint8_t reserved; /* */ blkif_vdev_t handle; /* same as for read/write requests */ uint64_t id; /* private guest value, echoed in resp */ blkif_sector_t sector_number;/* start sector idx on disk */ uint64_t nr_sectors; /* number of contiguous sectors to trim */ + /* ignored if ''discard-secure=0'' */ +#define BLKIF_OP_DISCARD_FLAG_SECURE (1<<0) + uint32_t flag; + uint32_t pad; }; -typedef struct blkif_request_trim blkif_request_trim_t; +typedef struct blkif_request_discard blkif_request_discard_t; struct blkif_response { uint64_t id; /* copied from request */ _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Konrad Rzeszutek Wilk
2011-Oct-11 18:27 UTC
Re: [Xen-devel] [PATCH 1 of 1] interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD
On Mon, Oct 10, 2011 at 03:58:42PM -0400, Konrad Rzeszutek Wilk wrote:> On Mon, Oct 10, 2011 at 01:50:11PM -0400, Konrad Rzeszutek Wilk wrote:Per Ian and Jan''s suggestion (note, the structure is 4-byte aligned so we do not need to pad it): # HG changeset patch # Parent 72f339bc600d7a9629d3f9eb8a279fbf8be25b12 interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD The name ''trim'' is specific to the ATA discard implementation. The name ''scsi unmap'' is specific to the SCSI discard implementation. We should really use a generic name - and the name ''discard'' looks to be the most generic of them all. Also update the description to mention the other parameters that the frontend can query the backend for: discard-aligment, discard-granularity, and discard-secure. We also utilize per Jan Beulich keen suggestion, the 8-bit reserved field to use as a flag value. Currently the only flag that can be passed for a discard operation is secure delete: BLKIF_OP_DISCARD_FLAG_SECURE. CC: lidongyang@novell.com CC: owen.smith@citrix.com CC: Pasi Kärkkäinen <pasik@iki.fi> CC: JBeulich@novell.com Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> diff -r 72f339bc600d xen/include/public/io/blkif.h --- a/xen/include/public/io/blkif.h Mon Oct 10 11:21:51 2011 +0100 +++ b/xen/include/public/io/blkif.h Tue Oct 11 14:10:33 2011 -0400 @@ -82,26 +82,47 @@ */ #define BLKIF_OP_RESERVED_1 4 /* - * Recognised only if "feature-trim" is present in backend xenbus info. - * The "feature-trim" node contains a boolean indicating whether trim - * requests are likely to succeed or fail. Either way, a trim request + * Recognised only if "feature-discard" is present in backend xenbus info. + * The "feature-discard" node contains a boolean indicating whether trim + * (ATA) or unmap (SCSI) - conviently called discard requests are likely + * to succeed or fail. Either way, a discard request * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by * the underlying block-device hardware. The boolean simply indicates whether - * or not it is worthwhile for the frontend to attempt trim requests. - * If a backend does not recognise BLKIF_OP_TRIM, it should *not* - * create the "feature-trim" node! - * - * Trim operation is a request for the underlying block device to mark - * extents to be erased. Trim operations are passed with sector_number as the - * sector index to begin trim operations at and nr_sectors as the number of - * sectors to be trimmed. The specified sectors should be trimmed if the - * underlying block device supports trim operations, or a BLKIF_RSP_EOPNOTSUPP - * should be returned. More information about trim operations at: + * or not it is worthwhile for the frontend to attempt discard requests. + * If a backend does not recognise BLKIF_OP_DISCARD, it should *not* + * create the "feature-discard" node! + * + * Discard operation is a request for the underlying block device to mark + * extents to be erased. However, discard does not guarantee that the blocks + * will be erased from the device - it is just a hint to the device + * controller that these blocks are no longer in use. What the device + * controller does with that information is left to the controller. + * Discard operations are passed with sector_number as the + * sector index to begin discard operations at and nr_sectors as the number of + * sectors to be discarded. The specified sectors should be discarded if the + * underlying block device supports trim (ATA) or unmap (SCSI) operations, + * or a BLKIF_RSP_EOPNOTSUPP should be returned. + * More information about trim/unmap operations at: * http://t13.org/Documents/UploadedDocuments/docs2008/ * 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. */ -#define BLKIF_OP_TRIM 5 - +#define BLKIF_OP_DISCARD 5 /* * Maximum scatter/gather segments per request. * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE. @@ -134,18 +155,20 @@ struct blkif_request { typedef struct blkif_request blkif_request_t; /* - * Cast to this structure when blkif_request.operation == BLKIF_OP_TRIM - * sizeof(struct blkif_request_trim) <= sizeof(struct blkif_request) + * Cast to this structure when blkif_request.operation == BLKIF_OP_DISCARD + * sizeof(struct blkif_request_discard) <= sizeof(struct blkif_request) */ -struct blkif_request_trim { - uint8_t operation; /* BLKIF_OP_TRIM */ - uint8_t reserved; /* */ +struct blkif_request_discard { + uint8_t operation; /* BLKIF_OP_DISCARD */ + /* ignored if ''discard-secure=0'' */ +#define BLKIF_OP_DISCARD_FLAG_SECURE (1<<0) + uint8_t flag; /* BLKIF_OP_DISCARD_FLAG_SECURE or 0 */ blkif_vdev_t handle; /* same as for read/write requests */ uint64_t id; /* private guest value, echoed in resp */ blkif_sector_t sector_number;/* start sector idx on disk */ uint64_t nr_sectors; /* number of contiguous sectors to trim */ }; -typedef struct blkif_request_trim blkif_request_trim_t; +typedef struct blkif_request_discard blkif_request_discard_t; struct blkif_response { uint64_t id; /* copied from request */ _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jan Beulich
2011-Oct-12 10:08 UTC
Re: [Xen-devel] [PATCH 1 of 1] interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD
>>> On 11.10.11 at 20:27, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote: > On Mon, Oct 10, 2011 at 03:58:42PM -0400, Konrad Rzeszutek Wilk wrote: >> On Mon, Oct 10, 2011 at 01:50:11PM -0400, Konrad Rzeszutek Wilk wrote: > > Per Ian and Jan''s suggestion (note, the structure is 4-byte aligned > so we do not need to pad it): > > # HG changeset patch > # Parent 72f339bc600d7a9629d3f9eb8a279fbf8be25b12 > interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD > > The name ''trim'' is specific to the ATA discard implementation. > The name ''scsi unmap'' is specific to the SCSI discard implementation. > > We should really use a generic name - and the name ''discard'' > looks to be the most generic of them all. Also update the description > to mention the other parameters that the frontend can query the > backend for: discard-aligment, discard-granularity, and > discard-secure. We also utilize per Jan Beulich keen suggestion, > the 8-bit reserved field to use as a flag value. Currently the only > flag that can be passed for a discard operation is secure delete: > BLKIF_OP_DISCARD_FLAG_SECURE. > > CC: lidongyang@novell.com > CC: owen.smith@citrix.com > CC: Pasi Kärkkäinen <pasik@iki.fi> > CC: JBeulich@novell.com > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > > diff -r 72f339bc600d xen/include/public/io/blkif.h > --- a/xen/include/public/io/blkif.h Mon Oct 10 11:21:51 2011 +0100 > +++ b/xen/include/public/io/blkif.h Tue Oct 11 14:10:33 2011 -0400 > @@ -82,26 +82,47 @@ > */ > #define BLKIF_OP_RESERVED_1 4 > /* > - * Recognised only if "feature-trim" is present in backend xenbus info. > - * The "feature-trim" node contains a boolean indicating whether trim > - * requests are likely to succeed or fail. Either way, a trim request > + * Recognised only if "feature-discard" is present in backend xenbus info. > + * The "feature-discard" node contains a boolean indicating whether trim > + * (ATA) or unmap (SCSI) - conviently called discard requests are likely > + * to succeed or fail. Either way, a discard request > * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by > * the underlying block-device hardware. The boolean simply indicates > whether > - * or not it is worthwhile for the frontend to attempt trim requests. > - * If a backend does not recognise BLKIF_OP_TRIM, it should *not* > - * create the "feature-trim" node! > - * > - * Trim operation is a request for the underlying block device to mark > - * extents to be erased. Trim operations are passed with sector_number as > the > - * sector index to begin trim operations at and nr_sectors as the number of > - * sectors to be trimmed. The specified sectors should be trimmed if the > - * underlying block device supports trim operations, or a > BLKIF_RSP_EOPNOTSUPP > - * should be returned. More information about trim operations at: > + * or not it is worthwhile for the frontend to attempt discard requests. > + * If a backend does not recognise BLKIF_OP_DISCARD, it should *not* > + * create the "feature-discard" node! > + * > + * Discard operation is a request for the underlying block device to mark > + * extents to be erased. However, discard does not guarantee that the > blocks > + * will be erased from the device - it is just a hint to the device > + * controller that these blocks are no longer in use. What the device > + * controller does with that information is left to the controller. > + * Discard operations are passed with sector_number as the > + * sector index to begin discard operations at and nr_sectors as the number > of > + * sectors to be discarded. The specified sectors should be discarded if > the > + * underlying block device supports trim (ATA) or unmap (SCSI) operations, > + * or a BLKIF_RSP_EOPNOTSUPP should be returned. > + * More information about trim/unmap operations at: > * http://t13.org/Documents/UploadedDocuments/docs2008/ > * 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. > */ > -#define BLKIF_OP_TRIM 5 > - > +#define BLKIF_OP_DISCARD 5 > /* > * Maximum scatter/gather segments per request. > * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE. > @@ -134,18 +155,20 @@ struct blkif_request { > typedef struct blkif_request blkif_request_t; > > /* > - * Cast to this structure when blkif_request.operation == BLKIF_OP_TRIM > - * sizeof(struct blkif_request_trim) <= sizeof(struct blkif_request) > + * Cast to this structure when blkif_request.operation == BLKIF_OP_DISCARD > + * sizeof(struct blkif_request_discard) <= sizeof(struct blkif_request) > */ > -struct blkif_request_trim { > - uint8_t operation; /* BLKIF_OP_TRIM */ > - uint8_t reserved; /* */ > +struct blkif_request_discard { > + uint8_t operation; /* BLKIF_OP_DISCARD */ > + /* ignored if ''discard-secure=0'' */ > +#define BLKIF_OP_DISCARD_FLAG_SECURE (1<<0)I''d like to have the _OP in here dropped - BLKIF_OP_* should be "reserved" to express actual operations. With that change, Acked-by: Jan Beulich <jbeulich@suse.com> (I''d also consider the _FLAG part to be sort of redundant.) Jan> + uint8_t flag; /* BLKIF_OP_DISCARD_FLAG_SECURE or 0 */ > blkif_vdev_t handle; /* same as for read/write requests */ > uint64_t id; /* private guest value, echoed in resp */ > blkif_sector_t sector_number;/* start sector idx on disk */ > uint64_t nr_sectors; /* number of contiguous sectors to trim */ > }; > -typedef struct blkif_request_trim blkif_request_trim_t; > +typedef struct blkif_request_discard blkif_request_discard_t; > > struct blkif_response { > uint64_t id; /* copied from request */_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Ian Campbell
2011-Oct-12 10:40 UTC
Re: [Xen-devel] [PATCH 1 of 1] interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD
On Tue, 2011-10-11 at 19:27 +0100, Konrad Rzeszutek Wilk wrote:> On Mon, Oct 10, 2011 at 03:58:42PM -0400, Konrad Rzeszutek Wilk wrote: > > On Mon, Oct 10, 2011 at 01:50:11PM -0400, Konrad Rzeszutek Wilk wrote: > > Per Ian and Jan''s suggestion (note, the structure is 4-byte aligned > so we do not need to pad it): > > # HG changeset patch > # Parent 72f339bc600d7a9629d3f9eb8a279fbf8be25b12 > interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD > > The name ''trim'' is specific to the ATA discard implementation. > The name ''scsi unmap'' is specific to the SCSI discard implementation. > > We should really use a generic name - and the name ''discard'' > looks to be the most generic of them all. Also update the description > to mention the other parameters that the frontend can query the > backend for: discard-aligment, discard-granularity, and > discard-secure. We also utilize per Jan Beulich keen suggestion, > the 8-bit reserved field to use as a flag value. Currently the only > flag that can be passed for a discard operation is secure delete: > BLKIF_OP_DISCARD_FLAG_SECURE.This change seems to be conflating a large rename with new data fields, changes to the documentation in the comments and other bits and bobs, which makes it pretty hard to review it''s actual impact. Can we get them separately? Ian.> > CC: lidongyang@novell.com > CC: owen.smith@citrix.com > CC: Pasi Kärkkäinen <pasik@iki.fi> > CC: JBeulich@novell.com > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > > diff -r 72f339bc600d xen/include/public/io/blkif.h > --- a/xen/include/public/io/blkif.h Mon Oct 10 11:21:51 2011 +0100 > +++ b/xen/include/public/io/blkif.h Tue Oct 11 14:10:33 2011 -0400 > @@ -82,26 +82,47 @@ > */ > #define BLKIF_OP_RESERVED_1 4 > /* > - * Recognised only if "feature-trim" is present in backend xenbus info. > - * The "feature-trim" node contains a boolean indicating whether trim > - * requests are likely to succeed or fail. Either way, a trim request > + * Recognised only if "feature-discard" is present in backend xenbus info. > + * The "feature-discard" node contains a boolean indicating whether trim > + * (ATA) or unmap (SCSI) - conviently called discard requests are likely > + * to succeed or fail. Either way, a discard request > * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by > * the underlying block-device hardware. The boolean simply indicates whether > - * or not it is worthwhile for the frontend to attempt trim requests. > - * If a backend does not recognise BLKIF_OP_TRIM, it should *not* > - * create the "feature-trim" node! > - * > - * Trim operation is a request for the underlying block device to mark > - * extents to be erased. Trim operations are passed with sector_number as the > - * sector index to begin trim operations at and nr_sectors as the number of > - * sectors to be trimmed. The specified sectors should be trimmed if the > - * underlying block device supports trim operations, or a BLKIF_RSP_EOPNOTSUPP > - * should be returned. More information about trim operations at: > + * or not it is worthwhile for the frontend to attempt discard requests. > + * If a backend does not recognise BLKIF_OP_DISCARD, it should *not* > + * create the "feature-discard" node! > + * > + * Discard operation is a request for the underlying block device to mark > + * extents to be erased. However, discard does not guarantee that the blocks > + * will be erased from the device - it is just a hint to the device > + * controller that these blocks are no longer in use. What the device > + * controller does with that information is left to the controller. > + * Discard operations are passed with sector_number as the > + * sector index to begin discard operations at and nr_sectors as the number of > + * sectors to be discarded. The specified sectors should be discarded if the > + * underlying block device supports trim (ATA) or unmap (SCSI) operations, > + * or a BLKIF_RSP_EOPNOTSUPP should be returned. > + * More information about trim/unmap operations at: > * http://t13.org/Documents/UploadedDocuments/docs2008/ > * 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. > */ > -#define BLKIF_OP_TRIM 5 > - > +#define BLKIF_OP_DISCARD 5 > /* > * Maximum scatter/gather segments per request. > * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE. > @@ -134,18 +155,20 @@ struct blkif_request { > typedef struct blkif_request blkif_request_t; > > /* > - * Cast to this structure when blkif_request.operation == BLKIF_OP_TRIM > - * sizeof(struct blkif_request_trim) <= sizeof(struct blkif_request) > + * Cast to this structure when blkif_request.operation == BLKIF_OP_DISCARD > + * sizeof(struct blkif_request_discard) <= sizeof(struct blkif_request) > */ > -struct blkif_request_trim { > - uint8_t operation; /* BLKIF_OP_TRIM */ > - uint8_t reserved; /* */ > +struct blkif_request_discard { > + uint8_t operation; /* BLKIF_OP_DISCARD */ > + /* ignored if ''discard-secure=0'' */ > +#define BLKIF_OP_DISCARD_FLAG_SECURE (1<<0) > + uint8_t flag; /* BLKIF_OP_DISCARD_FLAG_SECURE or 0 */ > blkif_vdev_t handle; /* same as for read/write requests */ > uint64_t id; /* private guest value, echoed in resp */ > blkif_sector_t sector_number;/* start sector idx on disk */ > uint64_t nr_sectors; /* number of contiguous sectors to trim */ > }; > -typedef struct blkif_request_trim blkif_request_trim_t; > +typedef struct blkif_request_discard blkif_request_discard_t; > > struct blkif_response { > uint64_t id; /* copied from request */_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Konrad Rzeszutek Wilk
2011-Oct-12 15:22 UTC
Re: [Xen-devel] [PATCH 1 of 1] interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD
On Wed, Oct 12, 2011 at 11:40:04AM +0100, Ian Campbell wrote:> On Tue, 2011-10-11 at 19:27 +0100, Konrad Rzeszutek Wilk wrote: > > On Mon, Oct 10, 2011 at 03:58:42PM -0400, Konrad Rzeszutek Wilk wrote: > > > On Mon, Oct 10, 2011 at 01:50:11PM -0400, Konrad Rzeszutek Wilk wrote: > > > > Per Ian and Jan''s suggestion (note, the structure is 4-byte aligned > > so we do not need to pad it): > > > > # HG changeset patch > > # Parent 72f339bc600d7a9629d3f9eb8a279fbf8be25b12 > > interface: BLKIF_OP_TRIM -> BLKIF_OP_DISCARD > > > > The name ''trim'' is specific to the ATA discard implementation. > > The name ''scsi unmap'' is specific to the SCSI discard implementation. > > > > We should really use a generic name - and the name ''discard'' > > looks to be the most generic of them all. Also update the description > > to mention the other parameters that the frontend can query the > > backend for: discard-aligment, discard-granularity, and > > discard-secure. We also utilize per Jan Beulich keen suggestion, > > the 8-bit reserved field to use as a flag value. Currently the only > > flag that can be passed for a discard operation is secure delete: > > BLKIF_OP_DISCARD_FLAG_SECURE. > > This change seems to be conflating a large rename with new data fields, > changes to the documentation in the comments and other bits and bobs, > which makes it pretty hard to review it''s actual impact. Can we get them > separately?Of course. Sent them along with Jan''s Acked-by flag. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel