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qemu-img: Convert with copy offloading 

The new blk_co_copy_range interface offers a more efficient way in the
case of network based storage. Make use of it to allow faster convert
operation.

Since copy offloading cannot do zero detection ('-S') and compression
(-c), only try it when these options are not used.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20180601092648.24614-11-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Fam Zheng 2018-06-01 17:26:48 +08:00 committed by Stefan Hajnoczi
parent b5679fa49c
commit ee5306d092
1 changed files with 48 additions and 2 deletions
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50
qemu-img.c
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@ -1547,6 +1547,7 @@ typedef struct ImgConvertState {
bool compressed;
bool target_has_backing;
bool wr_in_order;
bool copy_range;
int min_sparse;
size_t cluster_sectors;
size_t buf_sectors;
@ -1740,6 +1741,37 @@ static int coroutine_fn convert_co_write(ImgConvertState *s, int64_t sector_num,
return 0;
}
static int coroutine_fn convert_co_copy_range(ImgConvertState *s, int64_t sector_num,
int nb_sectors)
{
int n, ret;
while (nb_sectors > 0) {
BlockBackend *blk;
int src_cur;
int64_t bs_sectors, src_cur_offset;
int64_t offset;
convert_select_part(s, sector_num, &src_cur, &src_cur_offset);
offset = (sector_num - src_cur_offset) << BDRV_SECTOR_BITS;
blk = s->src[src_cur];
bs_sectors = s->src_sectors[src_cur];
n = MIN(nb_sectors, bs_sectors - (sector_num - src_cur_offset));
ret = blk_co_copy_range(blk, offset, s->target,
sector_num << BDRV_SECTOR_BITS,
n << BDRV_SECTOR_BITS, 0);
if (ret < 0) {
return ret;
}
sector_num += n;
nb_sectors -= n;
}
return 0;
}
static void coroutine_fn convert_co_do_copy(void *opaque)
{
ImgConvertState *s = opaque;
@ -1762,6 +1794,7 @@ static void coroutine_fn convert_co_do_copy(void *opaque)
int n;
int64_t sector_num;
enum ImgConvertBlockStatus status;
bool copy_range;
qemu_co_mutex_lock(&s->lock);
if (s->ret != -EINPROGRESS || s->sector_num >= s->total_sectors) {
@ -1791,7 +1824,9 @@ static void coroutine_fn convert_co_do_copy(void *opaque)
s->allocated_sectors, 0);
}
if (status == BLK_DATA) {
retry:
copy_range = s->copy_range && s->status == BLK_DATA;
if (status == BLK_DATA && !copy_range) {
ret = convert_co_read(s, sector_num, n, buf);
if (ret < 0) {
error_report("error while reading sector %" PRId64
@ -1813,7 +1848,15 @@ static void coroutine_fn convert_co_do_copy(void *opaque)
}
if (s->ret == -EINPROGRESS) {
ret = convert_co_write(s, sector_num, n, buf, status);
if (copy_range) {
ret = convert_co_copy_range(s, sector_num, n);
if (ret) {
s->copy_range = false;
goto retry;
}
} else {
ret = convert_co_write(s, sector_num, n, buf, status);
}
if (ret < 0) {
error_report("error while writing sector %" PRId64
": %s", sector_num, strerror(-ret));
@ -1936,6 +1979,7 @@ static int img_convert(int argc, char **argv)
ImgConvertState s = (ImgConvertState) {
/* Need at least 4k of zeros for sparse detection */
.min_sparse = 8,
.copy_range = true,
.buf_sectors = IO_BUF_SIZE / BDRV_SECTOR_SIZE,
.wr_in_order = true,
.num_coroutines = 8,
@ -1976,6 +2020,7 @@ static int img_convert(int argc, char **argv)
break;
case 'c':
s.compressed = true;
s.copy_range = false;
break;
case 'o':
if (!is_valid_option_list(optarg)) {
@ -2017,6 +2062,7 @@ static int img_convert(int argc, char **argv)
}
s.min_sparse = sval / BDRV_SECTOR_SIZE;
s.copy_range = false;
break;
}
case 'p':