Re: [Qemu-devel] [PATCH] blockdev: fix cdrom read_only flag

[Kevin Wolf <kwolf@redhat.com>]

Am 15.10.2013 um 03:27 hat Fam Zheng geschrieben:
> Since 0ebd24e0, cdrom doesn't have read-only on by default, which will
> error out when using an read only image. Fix it by setting the default
> value when parsing opts.
> 
> Reported-by: Edivaldo de Araujo Pereira <edivaldoapereira@yahoo.com.br>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockdev.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 4f76e28..7f5ef4a 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -625,7 +625,8 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
>      int cyls, heads, secs, translation;
>      int max_devs, bus_id, unit_id, index;
>      const char *devaddr;
> -    bool read_only, copy_on_read;
> +    bool read_only = false;
> +    bool copy_on_read;
>      Error *local_err = NULL;
>  
>      /* Change legacy command line options into QMP ones */
> @@ -701,7 +702,7 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
>              media = MEDIA_DISK;
>          } else if (!strcmp(value, "cdrom")) {
>              media = MEDIA_CDROM;
> -            qdict_put(bs_opts, "read-only", qstring_from_str("on"));
> +            read_only = true;
>          } else {
>              error_report("'%s' invalid media", value);
>              goto fail;
> @@ -709,7 +710,7 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
>      }
>  
>      /* copy-on-read is disabled with a warning for read-only devices */
> -    read_only = qemu_opt_get_bool(legacy_opts, "read-only", false);
> +    read_only = qemu_opt_get_bool(legacy_opts, "read-only", read_only);

I believe we must move this line to above the media=... handling for
compatibility with old versions. Or actually, using |= instead of = may
be enough.

The reason is this command line:

    -drive file=test.iso,media=cdrom,readonly=off

Which, "obviously", means that a read-only CD-ROM device should be
created.

Kevin