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authorLidong Chen <lidongchen@tencent.com>2017-04-13 10:34:28 +0800
committerStefan Hajnoczi <stefanha@redhat.com>2017-04-21 10:36:12 +0100
commit3928d50bf151d2f25fde93432b0ee1d8eddd982d (patch)
treee0cd11b557ef32e5edc082429cd1d8db91308fba /migration/block.c
parentd72915c60bff51495529449750e051d01b03c62f (diff)
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 <stefanha@redhat.com> Signed-off-by: Lidong Chen <lidongchen@tencent.com> Message-id: 1492050868-16200-1-git-send-email-lidongchen@tencent.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'migration/block.c')
-rw-r--r--migration/block.c35
1 files 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);
}