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[Qemu-devel] [PATCH 02/41] sheepdog: do not blindly memset all read buff
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 02/41] sheepdog: do not blindly memset all read buffers |
Date: |
Tue, 17 Jul 2012 17:59:59 +0200 |
From: Christoph Hellwig <address@hidden>
Only buffers that map to unallocated blocks need to be zeroed.
Signed-off-by: Christoph Hellwig <address@hidden>
Acked-by: MORITA Kazutaka <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block/sheepdog.c | 37 ++++++++++++++++++-------------------
1 files changed, 18 insertions(+), 19 deletions(-)
diff --git a/block/sheepdog.c b/block/sheepdog.c
index 465dc97..a04ad99 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -1571,18 +1571,25 @@ static int coroutine_fn sd_co_rw_vector(void *p)
len = MIN(total - done, SD_DATA_OBJ_SIZE - offset);
- if (!inode->data_vdi_id[idx]) {
- if (acb->aiocb_type == AIOCB_READ_UDATA) {
+ switch (acb->aiocb_type) {
+ case AIOCB_READ_UDATA:
+ if (!inode->data_vdi_id[idx]) {
+ qemu_iovec_memset(acb->qiov, done, 0, len);
goto done;
}
-
- create = 1;
- } else if (acb->aiocb_type == AIOCB_WRITE_UDATA
- && !is_data_obj_writable(inode, idx)) {
- /* Copy-On-Write */
- create = 1;
- old_oid = oid;
- flags = SD_FLAG_CMD_COW;
+ break;
+ case AIOCB_WRITE_UDATA:
+ if (!inode->data_vdi_id[idx]) {
+ create = 1;
+ } else if (!is_data_obj_writable(inode, idx)) {
+ /* Copy-On-Write */
+ create = 1;
+ old_oid = oid;
+ flags = SD_FLAG_CMD_COW;
+ }
+ break;
+ default:
+ break;
}
if (create) {
@@ -1668,20 +1675,12 @@ static coroutine_fn int sd_co_readv(BlockDriverState
*bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
SheepdogAIOCB *acb;
- int i, ret;
+ int ret;
acb = sd_aio_setup(bs, qiov, sector_num, nb_sectors, NULL, NULL);
acb->aiocb_type = AIOCB_READ_UDATA;
acb->aio_done_func = sd_finish_aiocb;
- /*
- * TODO: we can do better; we don't need to initialize
- * blindly.
- */
- for (i = 0; i < qiov->niov; i++) {
- memset(qiov->iov[i].iov_base, 0, qiov->iov[i].iov_len);
- }
-
ret = sd_co_rw_vector(acb);
if (ret <= 0) {
qemu_aio_release(acb);
--
1.7.6.5
- [Qemu-devel] [PULL 00/41] Block patches, Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 01/41] sheepdog: always use coroutine-based network functions, Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 02/41] sheepdog: do not blindly memset all read buffers,
Kevin Wolf <=
- [Qemu-devel] [PATCH 03/41] fdc: Move floppy geometry guessing back from block.c, Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 09/41] hd-geometry: Unnest conditional in hd_geometry_guess(), Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 07/41] hd-geometry: Move disk geometry guessing back from block.c, Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 05/41] vvfat: Do not clobber the user's geometry, Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 11/41] hd-geometry: Clean up gratuitous goto in hd_geometry_guess(), Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 06/41] qtest: Add hard disk geometry test, Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 04/41] vvfat: Fix partition table, Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 10/41] hd-geometry: Factor out guess_chs_for_size(), Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 08/41] hd-geometry: Add tracepoints, Kevin Wolf, 2012/07/17
- [Qemu-devel] [PATCH 13/41] hd-geometry: Cut out block layer translation middleman, Kevin Wolf, 2012/07/17