Re: [RFC][PATCH 0/3] ext4 online defrag (ver 0.2)

[Joel Becker <Joel.Becker@oracle.com>]

On Tue, Jan 16, 2007 at 12:21:34PM -0700, Andreas Dilger wrote:
> On Jan 16, 2007  21:03 +0900, sho@tnes.nec.co.jp wrote:
> > 2. The new entry "goal" is added on ext4_ext_defrag_data structure
> >    which is passed to existing ioctl(EXT4_IOC_DEFRAG)
> >    as the argument.  The kernel starts searching the free blocks
> >    from "goal".  The command passes the physical block number
> >    gotten in the above step(1) to the ioctl.
> > 
> > struct ext4_ext_defrag_data {
> >         loff_t start_offset; /* start offset to defrag in byte */
> >         loff_t defrag_size;  /* size of defrag in bytes */
> > 	ext4_fsblk_t goal;   /* block offset for allocation */
> > };
> 
> Two things of note:
> - presumably the start_offset and defrag_size should be multiples of the
>   filesystem blocksize?  If they are not, is it an error or are they
>   adjusted to cover whole blocks?

	In fact, why aren't the units in blocks?  THe filesystem isn't
really going to deal with anything smaller, is it?

Joel

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Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127