Re: [Qemu-devel] [PATCH V4 3/6] qcow2: do not free clusters when fail in header update in qcow2_write_snapshots

[Max Reitz <mreitz@redhat.com>]

On 14.10.2013 23:52, Wenchao Xia wrote:
> Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
> ---
>  block/qcow2-snapshot.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
> index 4bd494b..c933b7f 100644
> --- a/block/qcow2-snapshot.c
> +++ b/block/qcow2-snapshot.c
> @@ -304,6 +304,13 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
>                     PRIi64 " with size %" PRIu64 ":%d (%s)",
>                     offsetof(QCowHeader, nb_snapshots), sizeof(header_data),
>                     ret, strerror(-ret));
> +        /*
> +         * If the snapshot data part have been updated on disk, Then the

s/have/has/; s/Then/then/

> +         * clusters at snapshot_offset may be used in next snapshot operation.
> +         * If we free those clusters in fail path, they may be allocated and
> +         * made dirty causing damage, so skip cluster free for safe.

s/for/to be/

> +         */
> +        snapshots_offset = 0;
>          goto fail;
>      }

Other then that: Reviewed-by: Max Reitz <mreitz@redhat.com>