https://bugzilla.redhat.com/show_bug.cgi?id=1763105

Signed-off-by: Han Han <hhan@redhat.com>
---
 qemu-img.texi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/qemu-img.texi b/qemu-img.texi
index b5156d6316..983c6122f8 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -763,6 +763,16 @@ file which is COW and has data blocks already, it couldn't be changed to NOCOW
 by setting @code{nocow=on}. One can issue @code{lsattr filename} to check if
 the NOCOW flag is set or not (Capital 'C' is NOCOW flag).
 
+@item data_file
+File name of data file that is stored in the image and used as a default for
+opening the image. If the option is used, qcow2 file only stores the metadata
+for the image.
+
+@item data_file_raw
+This option requires @option{data_file}. If this option is set to @code{on},
+qemu will always keep the external data file consistent as a standalone
+read-only raw image. Default value is @code{off}.
+
 @end table
 
 @item Other
-- 
2.20.1

On 10/20/19 9:14 PM, Han Han wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1763105
> 
> Signed-off-by: Han Han <hhan@redhat.com>
> ---
>  qemu-img.texi | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/qemu-img.texi b/qemu-img.texi
> index b5156d6316..983c6122f8 100644
> --- a/qemu-img.texi
> +++ b/qemu-img.texi
> @@ -763,6 +763,16 @@ file which is COW and has data blocks already, it couldn't be changed to NOCOW
>  by setting @code{nocow=on}. One can issue @code{lsattr filename} to check if
>  the NOCOW flag is set or not (Capital 'C' is NOCOW flag).
>  
> +@item data_file
> +File name of data file that is stored in the image and used as a default for
> +opening the image. If the option is used, qcow2 file only stores the metadata
> +for the image.
> +
> +@item data_file_raw
> +This option requires @option{data_file}. If this option is set to @code{on},
> +qemu will always keep the external data file consistent as a standalone
> +read-only raw image. Default value is @code{off}.
> +
>  @end table
>  
>  @item Other
> 

Reviewed-by: John Snow <jsnow@redhat.com>

On Mon, Oct 21, 2019 at 09:14:21AM +0800, Han Han wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1763105
> 
> Signed-off-by: Han Han <hhan@redhat.com>
> ---
>  qemu-img.texi | 10 ++++++++++
>  1 file changed, 10 insertions(+)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

On 21.10.19 03:14, Han Han wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1763105
> 
> Signed-off-by: Han Han <hhan@redhat.com>
> ---
>  qemu-img.texi | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/qemu-img.texi b/qemu-img.texi
> index b5156d6316..983c6122f8 100644
> --- a/qemu-img.texi
> +++ b/qemu-img.texi
> @@ -763,6 +763,16 @@ file which is COW and has data blocks already, it couldn't be changed to NOCOW
>  by setting @code{nocow=on}. One can issue @code{lsattr filename} to check if
>  the NOCOW flag is set or not (Capital 'C' is NOCOW flag).

Usually, I try not to be pedantic about specific phrasing and the like,
but this is going in the man page, so I suppose I have to be.

> +@item data_file
> +File name of data file that is stored in the image and used as a default for

This sounds a bit like the data file itself were stored in the image.

Also, I don’t think the bit about this being a default is necessary
because several qcow2 creation options are in some way only defaults
than can be overridden at runtime (like lazy_refcounts or backing_file).
 So I don’t think there is a need to make a mention of that here.

> +opening the image. If the option is used, qcow2 file only stores the metadata
> +for the image.

Maybe:

Path to a file in which to store all guest data.  If this option is
used, the qcow2 file will only contain the image's metadata.

> +
> +@item data_file_raw
> +This option requires @option{data_file}. If this option is set to @code{on},
> +qemu will always keep the external data file consistent as a standalone
> +read-only raw image. Default value is @code{off}.

For this paragraph OTOH I have absolutely no complaints. :-)

Max