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[Qemu-devel] [PULL 04/38] block/parallels: read up to cluster end in one
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 04/38] block/parallels: read up to cluster end in one go |
Date: |
Fri, 22 May 2015 10:01:36 +0100 |
From: Roman Kagan <address@hidden>
Teach parallels_read() to do reads in coarser granularity than just a
single sector: if requested, read up to the cluster end in one go.
Signed-off-by: Roman Kagan <address@hidden>
Reviewed-by: Denis V. Lunev <address@hidden>
Signed-off-by: Denis V. Lunev <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Message-id: address@hidden
CC: Kevin Wolf <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block/parallels.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index baefd3e..8770c82 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -159,6 +159,13 @@ static int64_t seek_to_sector(BDRVParallelsState *s,
int64_t sector_num)
return (uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset;
}
+static int cluster_remainder(BDRVParallelsState *s, int64_t sector_num,
+ int nb_sectors)
+{
+ int ret = s->tracks - sector_num % s->tracks;
+ return MIN(nb_sectors, ret);
+}
+
static int parallels_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
@@ -166,17 +173,18 @@ static int parallels_read(BlockDriverState *bs, int64_t
sector_num,
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, 1);
+ int ret = bdrv_read(bs->file, position, buf, n);
if (ret < 0) {
return ret;
}
} else {
- memset(buf, 0, BDRV_SECTOR_SIZE);
+ memset(buf, 0, n << BDRV_SECTOR_BITS);
}
- nb_sectors--;
- sector_num++;
- buf += BDRV_SECTOR_SIZE;
+ nb_sectors -= n;
+ sector_num += n;
+ buf += n << BDRV_SECTOR_BITS;
}
return 0;
}
--
2.1.0
- [Qemu-devel] [PULL 00/38] Block patches, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 02/38] block/parallels: rename parallels_header to ParallelsHeader, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 03/38] block/parallels: switch to bdrv_read, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 01/38] iotests, parallels: quote TEST_IMG in 076 test to be path-safe, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 05/38] block/parallels: add get_block_status, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 07/38] block/parallels: replace magic constants 4, 64 with proper sizeofs, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 08/38] block/parallels: mark parallels format driver as zero inited, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 06/38] block/parallels: provide _co_readv routine for parallels format driver, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 04/38] block/parallels: read up to cluster end in one go,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 09/38] block/parallels: _co_writev callback for Parallels format, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 11/38] block/parallels: support parallels image creation, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 10/38] iotests, parallels: test for write into Parallels image, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 12/38] iotests, parallels: test for newly created parallels image via qemu-img, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 13/38] parallels: change copyright information in the image header, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 14/38] block/parallels: rename catalog_ names to bat_, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 18/38] block/parallels: move parallels_open/probe to the very end of the file, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 16/38] block/parallels: keep BAT bitmap data in little endian in memory, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 15/38] block/parallels: create bat2sect helper, Stefan Hajnoczi, 2015/05/22
- [Qemu-devel] [PULL 19/38] block/parallels: implement parallels_check method of block driver, Stefan Hajnoczi, 2015/05/22