Aw: Re: [PATCH 2/2] commands: ubi: added the new command 'ubirename' to rename ubi volumes.

[iw3gtf at arcor.de]

Hi,


----- Original Nachricht ----
Von:     Sascha Hauer <s.hauer at pengutronix.de>
An:      Giorgio Dal Molin <iw3gtf at arcor.de>
Datum:   22.09.2016 10:04
Betreff: Re: [PATCH 2/2] commands: ubi: added the new command 'ubirename' to
 rename ubi volumes.

> On Wed, Sep 21, 2016 at 10:04:43AM +0200, Giorgio Dal Molin wrote:
> > From: Giorgio Dal Molin <giorgio.dal.molin at mobotix.com>
> > 
> > The syntax was taken from the corresponding command of the 'mts-utils'
> > userland package:
> > 
> > # ubirename UBIDEV OLD_NAME NEW_NAME [OLD_NAME NEW_NAME ...]
> > 
> > Signed-off-by: Giorgio Dal Molin <iw3gtf at arcor.de>
> > ---
> >  commands/ubi.c | 87
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 87 insertions(+)
> > 
> > diff --git a/commands/ubi.c b/commands/ubi.c
> > index 26b521f..3479340 100644
> > --- a/commands/ubi.c
> > +++ b/commands/ubi.c
> > @@ -6,6 +6,8 @@
> >  #include <errno.h>
> >  #include <getopt.h>
> >  #include <linux/mtd/mtd.h>
> > +#include <linux/mtd/ubi.h>
> > +#include <libgen.h>
> >  #include <linux/kernel.h>
> >  #include <linux/stat.h>
> >  #include <linux/mtd/mtd-abi.h>
> > @@ -306,3 +308,88 @@ BAREBOX_CMD_START(ubirmvol)
> >  	BAREBOX_CMD_GROUP(CMD_GRP_PART)
> >  	BAREBOX_CMD_HELP(cmd_ubirmvol_help)
> >  BAREBOX_CMD_END
> > +
> > +
> > +static int get_vol_id(const char *vol_name)
> > +{
> > +	struct ubi_volume_desc *desc;
> > +	struct cdev *vol_cdev;
> > +	struct ubi_volume_info vi;
> > +
> > +	vol_cdev = cdev_by_name(vol_name);
> > +	if(!vol_cdev) {
> > +		perror("cdev_by_name");
> > +		return -1;
> > +	}
> > +	desc = ubi_open_volume_cdev(vol_cdev, UBI_READONLY);
> > +	if(IS_ERR(desc)) {
> > +		perror("ubi_open_volume_cdev");
> > +		return -1;
> > +	}
> > +	ubi_get_volume_info(desc, &vi);
> > +	ubi_close_volume(desc);
> > +
> > +	return vi.vol_id;
> > +};
> 
> This get_vol_id() is not particularly nice. Also I do not like having
> the rename operation inside the ioctl parser as this means we cannot
> make the ubirename code optional for users that do not need renaming.
> 
> I just sent out a series which should help you in this regard. Can you
> base your code ontop of this?

I've noticed a problem in the 3rd patch ([PATCH 3/4] mtd: ubi: commands: use function API to access ubi volumes)
of your last UBI serie: in the resulting code in 'commands/ubi.c', function 'do_ubirmvol()':

...
	desc = ubi_open_volume_nm(ubinum, argv[2], UBI_EXCLUSIVE);
	if (IS_ERR(desc)) {
		ret = PTR_ERR(desc);
		printf("failed to open volume %s: %s\n", argv[2], strerror(-ret));
		goto err1;
	}

	ret = ubi_api_remove_volume(desc, 0);
	if (ret)
		printf("failed to remove volume %s: %s\n", argv[2], strerror(-ret));

err1:
	ubi_close_volume(desc);
err:
	close(fd);

	return ret ? 1 : 0;
}

You have a wrong 'goto err1': in that case the 'desc' pointer is not a memory address, it
represent a negative error code and you cannot use it in ubi_close_volume(desc) (it segfaults).

> 
> You should be able to get the vol_id with ubi_open_volume_nm() followed
> by ubi_get_volume_info().
> 
> The rename_volumes() from patch #1 should become a
> ubi_api_rename_volumes() directly called from the command code.
> 
> Sascha
> 

giorgio


Giorgio, iw3gtf at arcor.de