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[Qemu-devel] [PATCH 06/12] block/parallels: provide _co_readv routine fo
From: |
Denis V. Lunev |
Subject: |
[Qemu-devel] [PATCH 06/12] block/parallels: provide _co_readv routine for parallels format driver |
Date: |
Mon, 22 Dec 2014 16:06:04 +0300 |
Main approach is taken from qcow2_co_readv.
The patch drops coroutine lock for the duration of IO operation and
peforms normal scatter-gather IO using standard QEMU backend.
Signed-off-by: Denis V. Lunev <address@hidden>
Acked-by: Roman Kagan <address@hidden>
CC: Jeff Cody <address@hidden>
CC: Kevin Wolf <address@hidden>
CC: Stefan Hajnoczi <address@hidden>
---
block/parallels.c | 46 +++++++++++++++++++++++++++-------------------
1 file changed, 27 insertions(+), 19 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index b469984..64b169b 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -186,37 +186,45 @@ static int64_t coroutine_fn
parallels_co_get_block_status(BlockDriverState *bs,
BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
}
-static int parallels_read(BlockDriverState *bs, int64_t sector_num,
- uint8_t *buf, int nb_sectors)
+static coroutine_fn int parallels_co_readv(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
BDRVParallelsState *s = bs->opaque;
+ uint64_t bytes_done = 0;
+ QEMUIOVector hd_qiov;
+ int ret = 0;
+ qemu_iovec_init(&hd_qiov, qiov->niov);
+
+ qemu_co_mutex_lock(&s->lock);
while (nb_sectors > 0) {
int64_t position = seek_to_sector(s, sector_num);
int n = cluster_remainder(s, sector_num, nb_sectors);
- if (position >= 0) {
- int ret = bdrv_read(bs->file, position, buf, n);
+ int nbytes = n << BDRV_SECTOR_BITS;
+
+ if (position < 0) {
+ qemu_iovec_memset(qiov, bytes_done, 0, nbytes);
+ } else {
+ qemu_iovec_reset(&hd_qiov);
+ qemu_iovec_concat(&hd_qiov, qiov, bytes_done, nbytes);
+
+ qemu_co_mutex_unlock(&s->lock);
+ ret = bdrv_co_readv(bs->file, position, n, &hd_qiov);
+ qemu_co_mutex_lock(&s->lock);
+
if (ret < 0) {
- return ret;
+ goto fail;
}
- } else {
- memset(buf, 0, n << BDRV_SECTOR_BITS);
}
+
nb_sectors -= n;
sector_num += n;
- buf += n << BDRV_SECTOR_BITS;
+ bytes_done += nbytes;
}
- return 0;
-}
-
-static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t
sector_num,
- uint8_t *buf, int nb_sectors)
-{
- int ret;
- BDRVParallelsState *s = bs->opaque;
- qemu_co_mutex_lock(&s->lock);
- ret = parallels_read(bs, sector_num, buf, nb_sectors);
qemu_co_mutex_unlock(&s->lock);
+
+fail:
+ qemu_iovec_destroy(&hd_qiov);
return ret;
}
@@ -231,9 +239,9 @@ static BlockDriver bdrv_parallels = {
.instance_size = sizeof(BDRVParallelsState),
.bdrv_probe = parallels_probe,
.bdrv_open = parallels_open,
- .bdrv_read = parallels_co_read,
.bdrv_close = parallels_close,
.bdrv_co_get_block_status = parallels_co_get_block_status,
+ .bdrv_co_readv = parallels_co_readv,
};
static void bdrv_parallels_init(void)
--
1.9.1
- [Qemu-devel] [PATCH 0/12] write/create for Parallels images, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 02/12] block/parallels: rename parallels_header to ParallelsHeader, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 03/12] block/parallels: switch to bdrv_read, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 06/12] block/parallels: provide _co_readv routine for parallels format driver,
Denis V. Lunev <=
- [Qemu-devel] [PATCH 01/12] iotests, parallels: quote TEST_IMG in 076 test to be path-safe, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 07/12] block/parallels: replace magic constants 4, 64 with proper sizeofs, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 05/12] block/parallels: add get_block_status, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 04/12] block/parallels: read up to cluster end in one go, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 09/12] iotests, parallels: test for write into Parallels image, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 08/12] block/parallels: _co_writev callback for Parallels format, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 11/12] iotests, parallels: test for newly created parallels image via qemu-img, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 12/12] parallels: change copyright information in the image header, Denis V. Lunev, 2014/12/22
- [Qemu-devel] [PATCH 10/12] block/parallels: support parallels image creation, Denis V. Lunev, 2014/12/22