qemu-img: let 'qemu-img convert' flush data

The 'qemu-img convert -h' advertise that the default cache mode is
'writeback', while in fact it is 'unsafe'.

This patch 1) fix the help manual and 2) let bdrv_close() call bdrv_flush()

2) is needed because some backend storage doesn't have a self-flush
mechanism(for e.g., sheepdog), so we need to call bdrv_flush() to make
sure the image is really writen to the storage instead of hanging around
writeback cache forever.

Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Liu Yuan 2012-04-20 17:10:56 +08:00 committed by Kevin Wolf
parent 9eb0bfca96
commit 80ccf93b88
2 changed files with 3 additions and 2 deletions

View File

@ -812,6 +812,7 @@ unlink_and_fail:
void bdrv_close(BlockDriverState *bs)
{
bdrv_flush(bs);
if (bs->drv) {
if (bs->job) {
block_job_cancel_sync(bs->job);

View File

@ -66,8 +66,8 @@ static void help(void)
" 'filename' is a disk image filename\n"
" 'fmt' is the disk image format. It is guessed automatically in most cases\n"
" 'cache' is the cache mode used to write the output disk image, the valid\n"
" options are: 'none', 'writeback' (default), 'writethrough', 'directsync'\n"
" and 'unsafe'\n"
" options are: 'none', 'writeback' (default, except for convert), 'writethrough',\n"
" 'directsync' and 'unsafe' (default for convert)\n"
" 'size' is the disk image size in bytes. Optional suffixes\n"
" 'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M)\n"
" and T (terabyte, 1024G) are supported. 'b' is ignored.\n"