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[Qemu-devel] [PATCHv2 08/20] block: honour alignment and limit in bdrv_c
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCHv2 08/20] block: honour alignment and limit in bdrv_co_discard |
Date: |
Tue, 17 Sep 2013 15:48:44 +0200 |
Signed-off-by: Peter Lieven <address@hidden>
---
block.c | 34 +++++++++++++++++++++++++++++++++-
1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 74ec342..ecc5be4 100644
--- a/block.c
+++ b/block.c
@@ -4181,7 +4181,39 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs,
int64_t sector_num,
}
if (bs->drv->bdrv_co_discard) {
- return bs->drv->bdrv_co_discard(bs, sector_num, nb_sectors);
+ /* if no limit is specified in the BlockDriverState use a default
+ * of 32768 512-byte sectors (16 MiB) per request.
+ */
+ int max_discard = bs->max_discard ? bs->max_discard : 32768;
+
+ while (nb_sectors > 0) {
+ int ret;
+ int num = nb_sectors;
+
+ /* align request */
+ if (bs->discard_alignment &&
+ num >= bs->discard_alignment &&
+ sector_num % bs->discard_alignment) {
+ if (num > bs->discard_alignment) {
+ num = bs->discard_alignment;
+ }
+ num -= sector_num % bs->discard_alignment;
+ }
+
+ /* limit request size */
+ if (num > max_discard) {
+ num = max_discard;
+ }
+
+ ret = bs->drv->bdrv_co_discard(bs, sector_num, num);
+ if (ret) {
+ return ret;
+ }
+
+ sector_num += num;
+ nb_sectors -= num;
+ }
+ return 0;
} else if (bs->drv->bdrv_aio_discard) {
BlockDriverAIOCB *acb;
CoroutineIOCompletion co = {
--
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, 2013/09/17
- [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 <=
- [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
- [Qemu-devel] [PATCHv2 05/20] block/raw: add bdrv_has_discard_zeroes and bdrv_has_discard_write_zeroes, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 11/20] iscsi: add bdrv_has_discard_zeroes and bdrv_has_discard_write_zeroes, Peter Lieven, 2013/09/17
- [Qemu-devel] [PATCHv2 12/20] iscsi: add bdrv_co_write_zeroes, Peter Lieven, 2013/09/17