Re: Can't eject a previously mounted CD?

[Ed Sweetman]

In your patch here i think the person who made the code originally 
confused or got wrong the conditions of success for opening the cdrom 
drive. This is in the same function as the patch applies to.

       if ((fp->f_flags & O_NONBLOCK) && (cdi->options & 
CDO_USE_FFLAGS))
                ret = cdi->ops->open(cdi, 1); 

        else 

                ret = open_for_data(cdi); 



        if (!ret) cdi->use_count++;

Here we see that if the open fails we incriment our use_count.  But this 
doesn't make sense. We increment the use_count at the  beginning of the 
function as a "lock" so that we can't do anything while the open 
function is executing like rmmod the cdrom (supposedly?).  Now removing 
the if(!ret) line makes sense. Under the out: label, if the open fails, 
then we close our makeshift lock on the device because our function is 
done. If it succeeded, then the use_count stays at 1 we go along our 
merry way.

> -Walt
>
> --- /usr/src/linux/drivers/cdrom/cdrom.c        2003-12-25 09:53:59.000000000 -0800
> +++ linux-2.6.0-mm1/drivers/cdrom/cdrom.c       2003-12-28 19:42:04.174098225 -0800
> @@ -744,4 +744,7 @@
>         }
>
> +       if (cdi->use_count > 0)
> +               cdi->use_count--;
> +
>         /* if this was a O_NONBLOCK open and we should honor the flags,
>          * do a quick open without drive/disc integrity checks. */
> @@ -931,5 +934,5 @@
>         struct cdrom_device_ops *cdo = cdi->ops;
>
> -       cdinfo(CD_CLOSE, "entering cdrom_release\n");
> +       cdinfo(CD_CLOSE, "entering cdrom_release\n");
>
>         if (cdi->use_count > 0)
>
>
>
> -
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