From 3928d50bf151d2f25fde93432b0ee1d8eddd982d Mon Sep 17 00:00:00 2001 From: Lidong Chen Date: Thu, 13 Apr 2017 10:34:28 +0800 Subject: [PATCH] migration/block: use blk_pwrite_zeroes for each zero cluster BLOCK_SIZE is (1 << 20), qcow2 cluster size is 65536 by default, this may cause the qcow2 file size to be bigger after migration. This patch checks each cluster, using blk_pwrite_zeroes for each zero cluster. [Initialize cluster_size to BLOCK_SIZE to prevent a gcc uninitialized variable compiler warning. In reality we always initialize cluster_size in a conditional but gcc doesn't know that. --Stefan] Reviewed-by: Stefan Hajnoczi Signed-off-by: Lidong Chen Message-id: 1492050868-16200-1-git-send-email-lidongchen@tencent.com Signed-off-by: Stefan Hajnoczi --- migration/block.c | 35 +++++++++++++++++++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-) diff --git a/migration/block.c b/migration/block.c index 7734ff728a..060087fa32 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 = BLOCK_SIZE; do { addr = qemu_get_be64(f); @@ -919,6 +921,15 @@ static int block_load(QEMUFile *f, void *opaque, int version_id) error_report_err(local_err); return -EINVAL; } + + ret = bdrv_get_info(blk_bs(blk), &bdi); + if (ret == 0 && bdi.cluster_size > 0 && + bdi.cluster_size <= BLOCK_SIZE && + BLOCK_SIZE % bdi.cluster_size == 0) { + cluster_size = bdi.cluster_size; + } else { + cluster_size = BLOCK_SIZE; + } } if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) { @@ -932,10 +943,30 @@ static int block_load(QEMUFile *f, void *opaque, int version_id) nr_sectors * BDRV_SECTOR_SIZE, BDRV_REQ_MAY_UNMAP); } else { + int i; + int64_t cur_addr; + uint8_t *cur_buf; + 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); + 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 ((!block_mig_state.zero_blocks || + cluster_size < BLOCK_SIZE) && + 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) { + break; + } + } g_free(buf); }