Switch the .bdrv_read method implementation from using bdrv_pread() to
bdrv_read() on the underlying file, since the latter is subject to i/o
throttling while the former is not.
Besides, since bdrv_read() operates in sectors rather than bytes, adjust
the helper functions to do so too.
Signed-off-by: Roman Kagan <rkagan@parallels.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Message-id:
1430207220-24458-4-git-send-email-den@openvz.org
CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
+static int64_t seek_to_sector(BDRVParallelsState *s, int64_t sector_num)
- BDRVParallelsState *s = bs->opaque;
uint32_t index, offset;
index = sector_num / s->tracks;
uint32_t index, offset;
index = sector_num / s->tracks;
/* not allocated */
if ((index >= s->catalog_size) || (s->catalog_bitmap[index] == 0))
return -1;
/* not allocated */
if ((index >= s->catalog_size) || (s->catalog_bitmap[index] == 0))
return -1;
- return
- ((uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset) * 512;
+ return (uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset;
}
static int parallels_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
}
static int parallels_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
+ BDRVParallelsState *s = bs->opaque;
+
- int64_t position = seek_to_sector(bs, sector_num);
+ int64_t position = seek_to_sector(s, sector_num);
- if (bdrv_pread(bs->file, position, buf, 512) != 512)
- return -1;
+ int ret = bdrv_read(bs->file, position, buf, 1);
+ if (ret < 0) {
+ return ret;
+ }
+ memset(buf, 0, BDRV_SECTOR_SIZE);
}
nb_sectors--;
sector_num++;
}
nb_sectors--;
sector_num++;
+ buf += BDRV_SECTOR_SIZE;