[review request] zfsboot/zfsloader: support accessing filesystems within a pool

John Baldwin jhb at freebsd.org
Mon May 7 17:46:12 UTC 2012


On Monday, May 07, 2012 11:15:53 am Andriy Gapon wrote:
> on 07/05/2012 17:47 Andriy Gapon said the following:
> > on 07/05/2012 16:53 John Baldwin said the following:
> >> Ok.  Maybe add one comment to the bootargs.h head to explain that the 'bootargs'
> >> struct starts at ARGOFF and can grow up, while struct bootinfo is copied such that
> >> it's end is at the top of the argument area and grows down.
> > 
> > Will do.
> 
> Could you please check the wording and correct it or suggest alternatives?
> Thank you.
> 
> diff --git a/sys/boot/i386/common/bootargs.h b/sys/boot/i386/common/bootargs.h
> index 510efdd..8bc1b32 100644
> --- a/sys/boot/i386/common/bootargs.h
> +++ b/sys/boot/i386/common/bootargs.h
> @@ -29,6 +29,15 @@
>  #define	BF_OFF		8	/* offsetof(struct bootargs, bootflags) */
>  #define	BI_OFF		20	/* offsetof(struct bootargs, bootinfo) */
> 
> +/*
> + * We reserve some space above BTX allocated stack for the arguments
> + * and certain data that could hang off them.  Currently only struct bootinfo
> + * is supported in that category.  The bootinfo is placed at the top
> + * of the arguments area and the actual arguments are placed at ARGOFF offset
> + * from the top and grow towards the top.  Hopefully we have enough space
> + * for bootinfo and the arguments to not run into each other.
> + * Arguments area below ARGOFF is reserved for future use.
> + */
>  #define	ARGSPACE	0x1000	/* total size of the BTX args area */
>  #define	ARGOFF		0x800	/* actual args offset within the args area */
>  #define	ARGADJ		(ARGSPACE - ARGOFF)

I think this is good, thanks!

-- 
John Baldwin


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