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[Qemu-devel] [PATCHv4 08/17] block: honour BlockLimits in bdrv_co_discar
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCHv4 08/17] block: honour BlockLimits in bdrv_co_discard |
Date: |
Tue, 8 Oct 2013 13:58:02 +0200 |
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Peter Lieven <address@hidden>
---
block.c | 37 ++++++++++++++++++++++++++++++++++++-
1 file changed, 36 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 7551751..43d5f46 100644
--- a/block.c
+++ b/block.c
@@ -4209,6 +4209,11 @@ static void coroutine_fn bdrv_discard_co_entry(void
*opaque)
rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors);
}
+/* if no limit is specified in the BlockLimits use a default
+ * of 32768 512-byte sectors (16 MiB) per request.
+ */
+#define MAX_DISCARD_DEFAULT 32768
+
int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
int nb_sectors)
{
@@ -4230,7 +4235,37 @@ 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);
+ int max_discard = bs->bl.max_discard ?
+ bs->bl.max_discard : MAX_DISCARD_DEFAULT;
+
+ while (nb_sectors > 0) {
+ int ret;
+ int num = nb_sectors;
+
+ /* align request */
+ if (bs->bl.discard_alignment &&
+ num >= bs->bl.discard_alignment &&
+ sector_num % bs->bl.discard_alignment) {
+ if (num > bs->bl.discard_alignment) {
+ num = bs->bl.discard_alignment;
+ }
+ num -= sector_num % bs->bl.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] [PATCHv4 00/17] block: logical block provisioning enhancements, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 05/17] block/raw: add bdrv_has_discard_zeroes and bdrv_has_discard_write_zeroes, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 03/17] block: introduce BDRV_REQ_MAY_UNMAP request flag, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 01/17] block: make BdrvRequestFlags public, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 02/17] block: add flags to bdrv_*_write_zeroes, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 08/17] block: honour BlockLimits in bdrv_co_discard,
Peter Lieven <=
- [Qemu-devel] [PATCHv4 06/17] block: add BlockLimits structure to BlockDriverState, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 07/17] block: honour BlockLimits in bdrv_co_do_write_zeroes, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 09/17] iscsi: simplify iscsi_co_discard, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 11/17] iscsi: add bdrv_has_discard_zeroes and bdrv_has_discard_write_zeroes, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 04/17] block: introduce bdrv_has_discard_zeroes and bdrv_has_discard_write_zeroes, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 10/17] iscsi: set limits in BlockDriverState, Peter Lieven, 2013/10/08
- [Qemu-devel] [PATCHv4 14/17] block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks, Peter Lieven, 2013/10/08