On 08.08.2016 16:44, Kevin Wolf wrote:
Am 22.07.2016 um 10:17 hat Denis V. Lunev geschrieben:
From: Pavel Butsykin <pbutsy...@virtuozzo.com>
Added implementation of the qcow2_co_pwritev_compressed function that
will allow us to safely use compressed writes for the qcow2 from running
VMs.
Signed-off-by: Pavel Butsykin <pbutsy...@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
Signed-off-by: Denis V. Lunev <d...@openvz.org>
CC: Jeff Cody <jc...@redhat.com>
CC: Markus Armbruster <arm...@redhat.com>
CC: Eric Blake <ebl...@redhat.com>
CC: John Snow <js...@redhat.com>
CC: Stefan Hajnoczi <stefa...@redhat.com>
CC: Kevin Wolf <kw...@redhat.com>
/* XXX: put compressed sectors first, then all the cluster aligned
tables to avoid losing bytes in alignment */
-static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
- const uint8_t *buf, int nb_sectors)
+static coroutine_fn int
+qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
+ uint64_t bytes, QEMUIOVector *qiov)
{
BDRVQcow2State *s = bs->opaque;
+ QEMUIOVector hd_qiov;
+ struct iovec iov;
z_stream strm;
int ret, out_len;
- uint8_t *out_buf;
+ uint8_t *buf, *out_buf;
uint64_t cluster_offset;
- if (nb_sectors == 0) {
+ if (bytes == 0) {
/* align end of file to a sector boundary to ease reading with
sector based I/Os */
cluster_offset = bdrv_getlength(bs->file->bs);
return bdrv_truncate(bs->file->bs, cluster_offset);
}
- if (nb_sectors != s->cluster_sectors) {
+ if (bytes != s->cluster_size) {
ret = -EINVAL;
/* Zero-pad last write if image size is not cluster aligned */
- if (sector_num + nb_sectors == bs->total_sectors &&
- nb_sectors < s->cluster_sectors) {
+ if (offset + bytes == bs->total_sectors << BDRV_SECTOR_BITS &&
+ bytes < s->cluster_size)
+ {
uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
memset(pad_buf, 0, s->cluster_size);
- memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
- ret = qcow2_write_compressed(bs, sector_num,
- pad_buf, s->cluster_sectors);
+ qemu_iovec_to_buf(qiov, 0, pad_buf, s->cluster_size);
I think, bytes would be more exact than s->cluster_size here. Anyway,
shouldn't hurt because we stop at the end of the qiov anyway and its
size should match bytes.
Yes, I can send follow-up patches.
+ iov = (struct iovec) {
+ .iov_base = pad_buf,
+ .iov_len = s->cluster_size,
+ };
+ qemu_iovec_init_external(&hd_qiov, &iov, 1);
+ ret = qcow2_co_pwritev_compressed(bs, offset, bytes, &hd_qiov);
qemu_vfree(pad_buf);
}
return ret;
}
Kevin
