[PATCH 2/2] UBI: rename_volumes: Use UBI_METAONLY

[Guido Martínez]

On Mon, Nov 24, 2014 at 10:30:10PM +0100, Richard Weinberger wrote:
> By using UBI_METAONLY in rename_volumes() it is now possible to rename
> an UBI volume atomically while it is mounted.
> This is useful for firmware upgrades.
Minor nitpick: should this say 'while it is open for writing' or 'an
UBIFS volume'? Renaming volumes opened for read-only (with ubiblock on
top for example) was already supported.

Regardless:

Tested name swapping mounted UBIFS volumes and read-only ubiblocks, as
well as UBI volumes opened for writing (not updating).

(for both patches)
Tested-by: Guido Martínez <guido at vanguardiasur.com.ar>
Reviewed-by: Guido Martínez <guido at vanguardiasur.com.ar>

I'm not sure if we could now make the handler for UBI_IOCVOLUP take
read-write access instead of exclusive, but that's material for another
patch. Also I can't really think of a use case for that...


> Cc: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
> Cc: Andrew Murray <amurray at embedded-bits.co.uk>
> Signed-off-by: Richard Weinberger <richard at nod.at>
> ---
>  drivers/mtd/ubi/cdev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
> index f5c715c..286383c 100644
> --- a/drivers/mtd/ubi/cdev.c
> +++ b/drivers/mtd/ubi/cdev.c
> @@ -736,7 +736,7 @@ static int rename_volumes(struct ubi_device *ubi,
>  			goto out_free;
>  		}
>  
> -		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_READWRITE);
> +		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_METAONLY);
>  		if (IS_ERR(re->desc)) {
>  			err = PTR_ERR(re->desc);
>  			ubi_err(ubi, "cannot open volume %d, error %d",
> -- 
> 1.8.4.5
> 
> --
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-- 
Guido Martínez, VanguardiaSur
www.vanguardiasur.com.ar