[dm-devel] Re: [PATCH 1/3] Implement generic freeze feature

[Andreas Dilger]

On Aug 21, 2008  12:58 -0700, Andrew Morton wrote:
> >  #define FIGETBSZ   _IO(0x00,2)	/* get the block size used for bmap */
> > +#define FIFREEZE	_IOWR('X', 119, int)	/* Freeze */
> > +#define FITHAW		_IOWR('X', 120, int)	/* Thaw */
> 
> FIFREEZE is 119, but a few lines above we have
> 
> #define BLKDISCARD _IO(0x12,119)
>
> Should we be using 120 and 121 here?

No, because 'X' != 0x12...  The 'X' is used because this ioctl is compatible
with the XFS implementation of this feature.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.