From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48700) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwPWF-00018V-CF for qemu-devel@nongnu.org; Fri, 07 Apr 2017 04:45:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cwPWC-0002A3-97 for qemu-devel@nongnu.org; Fri, 07 Apr 2017 04:45:23 -0400 From: jemmy858585@gmail.com Date: Fri, 7 Apr 2017 16:44:45 +0800 Message-Id: <1491554685-1288-1-git-send-email-lidongchen@tencent.com> Subject: [Qemu-devel] [PATCH v2] migration/block: use blk_pwrite_zeroes for each zero cluster List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: stefanha@redhat.com, famz@redhat.com, quintela@redhat.com, dgilbert@redhat.com, qemu-block@nongnu.org, Lidong Chen From: Lidong Chen 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 --- migration/block.c | 37 +++++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) diff --git a/migration/block.c b/migration/block.c index 7734ff7..c32e046 100644 --- a/migration/block.c +++ b/migration/block.c @@ -885,6 +885,11 @@ static int block_load(QEMUFile *f, void *opaque, int version_id) int64_t total_sectors = 0; int nr_sectors; int ret; + int i; + int64_t addr_offset; + uint8_t *buf_offset; + BlockDriverInfo bdi; + int cluster_size; do { addr = qemu_get_be64(f); @@ -934,8 +939,36 @@ 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) { + for (i = 0; i < BLOCK_SIZE / cluster_size; i++) { + addr_offset = addr * BDRV_SECTOR_SIZE + + i * cluster_size; + buf_offset = buf + i * cluster_size; + + if (buffer_is_zero(buf_offset, cluster_size)) { + ret = blk_pwrite_zeroes(blk, addr_offset, + cluster_size, + BDRV_REQ_MAY_UNMAP); + } else { + ret = blk_pwrite(blk, addr_offset, buf_offset, + 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