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[Qemu-devel] [PATCHv2 04/20] block: introduce bdrv_has_discard_zeroes an
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCHv2 04/20] block: introduce bdrv_has_discard_zeroes and bdrv_has_discard_write_zeroes |
Date: |
Tue, 17 Sep 2013 15:48:40 +0200 |
Signed-off-by: Peter Lieven <address@hidden>
---
block.c | 29 +++++++++++++++++++++++++++++
include/block/block.h | 2 ++
include/block/block_int.h | 13 +++++++++++++
3 files changed, 44 insertions(+)
diff --git a/block.c b/block.c
index 6f498fc..177720e 100644
--- a/block.c
+++ b/block.c
@@ -3045,6 +3045,35 @@ int bdrv_has_zero_init(BlockDriverState *bs)
return 0;
}
+int bdrv_has_discard_zeroes(BlockDriverState *bs)
+{
+ assert(bs->drv);
+
+ if (bs->backing_hd) {
+ return 0;
+ }
+ if (bs->drv->bdrv_has_discard_zeroes) {
+ return bs->drv->bdrv_has_discard_zeroes(bs);
+ }
+
+ return 0;
+}
+
+int bdrv_has_discard_write_zeroes(BlockDriverState *bs)
+{
+ assert(bs->drv);
+
+ if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) {
+ return 0;
+ }
+
+ if (bs->drv->bdrv_has_discard_write_zeroes) {
+ return bs->drv->bdrv_has_discard_write_zeroes(bs);
+ }
+
+ return 0;
+}
+
typedef struct BdrvCoGetBlockStatusData {
BlockDriverState *bs;
BlockDriverState *base;
diff --git a/include/block/block.h b/include/block/block.h
index 0328234..8aa325a 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -307,6 +307,8 @@ int bdrv_discard(BlockDriverState *bs, int64_t sector_num,
int nb_sectors);
int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
int bdrv_has_zero_init_1(BlockDriverState *bs);
int bdrv_has_zero_init(BlockDriverState *bs);
+int bdrv_has_discard_zeroes(BlockDriverState *bs);
+int bdrv_has_discard_write_zeroes(BlockDriverState *bs);
int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum);
int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 26bad36..85c3474 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -202,6 +202,19 @@ struct BlockDriver {
*/
int (*bdrv_has_zero_init)(BlockDriverState *bs);
+ /*
+ * Returns 1 if discarded blocks read back as zeroes, 0 otherwise.
+ */
+ int (*bdrv_has_discard_zeroes)(BlockDriverState *bs);
+
+ /*
+ * Returns 1 if the driver can optimize writing zeroes by discarding
+ * sectors. It is additionally required that the block device is
+ * opened with BDRV_O_UNMAP and the that write zeroes request carries
+ * the BDRV_REQ_MAY_UNMAP flag for this to work.
+ */
+ int (*bdrv_has_discard_write_zeroes)(BlockDriverState *bs);
+
QLIST_ENTRY(BlockDriver) list;
};
--
1.7.9.5
- [Qemu-devel] [PATCHv2 00/20] block: logical block provisioning enhancements, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 01/20] block: make BdrvRequestFlags public, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 02/20] block: add flags to bdrv_*_write_zeroes, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 03/20] block: introduce BDRV_REQ_MAY_UNMAP request flag, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 04/20] block: introduce bdrv_has_discard_zeroes and bdrv_has_discard_write_zeroes,
Peter Lieven <=
- [Qemu-devel] [PATCHv2 06/20] block: add discard and write_zeroes limits and alignment to BlockDriverState, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 08/20] block: honour alignment and limit in bdrv_co_discard, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 10/20] iscsi: set limits in BlockDriverState, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 09/20] iscsi: simplify iscsi_co_discard, Peter Lieven, 2013/09/17