From: Lidong Chen <lidongc...@tencent.com>
BLOCK_SIZE is (1 << 20), qcow2 cluster size is 65536 by default,
this maybe cause the qcow2 file size is bigger after migration.
This patch check each cluster, use blk_pwrite_zeroes for each
zero cluster.
Signed-off-by: Lidong Chen <lidongc...@tencent.com>
---
migration/block.c | 38 ++++++++++++++++++++++++++++++++++++--
1 file changed, 36 insertions(+), 2 deletions(-)
diff --git a/migration/block.c b/migration/block.c
index 7734ff7..fe613db 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -885,6 +885,8 @@ static int block_load(QEMUFile *f, void *opaque, int
version_id)
int64_t total_sectors = 0;
int nr_sectors;
int ret;
+ BlockDriverInfo bdi;
+ int cluster_size;
do {
addr = qemu_get_be64(f);
@@ -934,8 +936,40 @@ static int block_load(QEMUFile *f, void *opaque, int
version_id)
} else {
buf = g_malloc(BLOCK_SIZE);
qemu_get_buffer(f, buf, BLOCK_SIZE);
- ret = blk_pwrite(blk, addr * BDRV_SECTOR_SIZE, buf,
- nr_sectors * BDRV_SECTOR_SIZE, 0);
+
+ ret = bdrv_get_info(blk_bs(blk), &bdi);
+ cluster_size = bdi.cluster_size;
+
+ if (ret == 0 && cluster_size > 0 &&
+ cluster_size <= BLOCK_SIZE &&
+ BLOCK_SIZE % cluster_size == 0) {
+ int i;
+ int64_t cur_addr;
+ uint8_t *cur_buf;
+
+ for (i = 0; i < BLOCK_SIZE / cluster_size; i++) {
+ cur_addr = addr * BDRV_SECTOR_SIZE
+ + i * cluster_size;
+ cur_buf = buf + i * cluster_size;
+
+ if (buffer_is_zero(cur_buf, cluster_size)) {
+ ret = blk_pwrite_zeroes(blk, cur_addr,
+ cluster_size,
+ BDRV_REQ_MAY_UNMAP);
+ } else {
+ ret = blk_pwrite(blk, cur_addr, cur_buf,
+ cluster_size, 0);
+ }
+
+ if (ret < 0) {
+ g_free(buf);
+ return ret;
+ }
+ }
+ } else {
+ ret = blk_pwrite(blk, addr * BDRV_SECTOR_SIZE, buf,
+ nr_sectors * BDRV_SECTOR_SIZE, 0);
+ }
g_free(buf);
}
--
1.8.3.1
