Am 08.12.2011 06:40, schrieb Li Zhi Hui:
> Signed-off-by: Li Zhi Hui <zhihu...@linux.vnet.ibm.com>
> ---
> block/cow.c | 22 ++++++++++++----------
> 1 files changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/block/cow.c b/block/cow.c
> index 3c52735..383482b 100644
> --- a/block/cow.c
> +++ b/block/cow.c
> @@ -64,10 +64,11 @@ static int cow_open(BlockDriverState *bs, int flags)
> struct cow_header_v2 cow_header;
> int bitmap_size;
> int64_t size;
> + int ret;
>
> /* see if it is a cow image */
> - if (bdrv_pread(bs->file, 0, &cow_header, sizeof(cow_header)) !=
> - sizeof(cow_header)) {
> + ret = bdrv_pread(bs->file, 0, &cow_header, sizeof(cow_header));
> + if (ret < 0) {
> goto fail;
> }
>
More context:
if (be32_to_cpu(cow_header.magic) != COW_MAGIC ||
be32_to_cpu(cow_header.version) != COW_VERSION) {
goto fail;
}
This jumps to fail: with uninitialised ret. Needs to be fixed.
> @@ -88,7 +89,7 @@ static int cow_open(BlockDriverState *bs, int flags)
> qemu_co_mutex_init(&s->lock);
> return 0;
> fail:
> - return -1;
> + return ret;
> }
>
> /*
> @@ -182,14 +183,14 @@ static int coroutine_fn cow_read(BlockDriverState *bs,
> int64_t sector_num,
> ret = bdrv_pread(bs->file,
> s->cow_sectors_offset + sector_num * 512,
> buf, n * 512);
> - if (ret != n * 512)
> - return -1;
> + if (ret < 0)
> + return ret;
Please add braces here while touching the code.
> } else {
> if (bs->backing_hd) {
> /* read from the base image */
> ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
> if (ret < 0)
> - return -1;
> + return ret;
And here.
Otherwise the patch looks good to me.
Kevin
