Re: [Ext2-devel] [RFC] Adding multiple block allocation

[Suparna Bhattacharya <suparna@in.ibm.com>]

On Fri, Apr 29, 2005 at 05:44:26PM -0700, Mingming Cao wrote:
> Oops, sorry about the empty message ...
> 
> > -static int ext3_writepages_get_block(struct inode *inode, sector_t iblock,
> > -			struct buffer_head *bh, int create)
> > +static int ext3_writepages_get_blocks(struct inode *inode, sector_t iblock,
> > +		unsigned long max_blocks, struct buffer_head *bh, int create)
> >  {
> > -	return ext3_direct_io_get_blocks(inode, iblock, 1, bh, create);
> > +	return ext3_direct_io_get_blocks(inode, iblock, max_blocks, bh, create);
> >  }
> >  
> 
> I have a question here, ext3_direct_io_get_blocks use DIO_CREDITS
> (EXT3_RESERVE_TRANS_BLOCKS + 32 = ) to reserve the space for
> journalling, but it seems based on assumption of one data block update
> once a time. Is it sufficent to re-use that routine for multiple block
> allocation here? Don't we need something like
> ext3_writepage_trans_blocks() here?

Quite likely - with your patch, as get_blocks actually allocates
multiple blocks at a time, the min credits estimate would 
change for ext3_direct_io_get_blocks/ext3_writepages_get_blocks.

Regards
Suparna

> 
> Thanks,
> Mingming
> 
> 
> 
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-- 
Suparna Bhattacharya (suparna@in.ibm.com)
Linux Technology Center
IBM Software Lab, India